Gene Summary

Gene:CASP7; caspase 7, apoptosis-related cysteine peptidase
Aliases: MCH3, CMH-1, LICE2, CASP-7, ICE-LAP3
Summary:This gene encodes a member of the cysteine-aspartic acid protease (caspase) family. Sequential activation of caspases plays a central role in the execution-phase of cell apoptosis. Caspases exist as inactive proenzymes which undergo proteolytic processing at conserved aspartic residues to produce two subunits, large and small, that dimerize to form the active enzyme. The precursor of the encoded protein is cleaved by caspase 3 and 10, is activated upon cell death stimuli and induces apoptosis. Alternatively spliced transcript variants encoding multiple isoforms have been observed for this gene. [provided by RefSeq, May 2012]
Databases:OMIM, VEGA, HGNC, Ensembl, GeneCard, Gene
Source:NCBIAccessed: 06 August, 2015


What does this gene/protein do?
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Pathways:What pathways are this gene/protein implicaed in?
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Cancer Overview

Research Indicators

Publications Per Year (1990-2015)
Graph generated 06 August 2015 using data from PubMed using criteria.

Literature Analysis

Mouse over the terms for more detail; many indicate links which you can click for dedicated pages about the topic.

Tag cloud generated 06 August, 2015 using data from PubMed, MeSH and CancerIndex

Specific Cancers (4)

Data table showing topics related to specific cancers and associated disorders. Scope includes mutations and abnormal protein expression.

Note: list is not exhaustive. Number of papers are based on searches of PubMed (click on topic title for arbitrary criteria used).

Latest Publications: CASP7 (cancer-related)

Majerciak V, Pripuzova N, Chan C, et al.
Stability of structured Kaposi's sarcoma-associated herpesvirus ORF57 protein is regulated by protein phosphorylation and homodimerization.
J Virol. 2015; 89(6):3256-74 [PubMed] Article available free on PMC after 15/09/2015 Related Publications
UNLABELLED: Kaposi's sarcoma-associated herpesvirus (KSHV) ORF57 plays an essential role in KSHV lytic infection by promoting viral gene expression at the posttranscriptional level. Using bioinformatic and biochemical approaches, we determined that ORF57 contains two structurally and functionally distinct domains: a disordered nonstructural N-terminal domain (amino acids [aa] 1 to 152) and a structured α-helix-rich C-terminal domain (aa 153 to 455). The N-terminal domain mediates ORF57 interaction with several RNA-protein complexes essential for ORF57 to function. The N-terminal phosphorylation by cellular casein kinase II (CKII) at S21, T32, and S43, and other cellular kinases at S95 and S97 residues in proximity of the caspase-7 cleavage site, 30-DETD-33, inhibits caspase-7 digestion of ORF57. The structured C-terminal domain mediates homodimerization of ORF57, and the critical region for this function was mapped carefully to α-helices 7 to 9. Introduction of point mutations into α-helix 7 at ORF57 aa 280 to 299, a region highly conserved among ORF57 homologues from other herpesviruses, inhibited ORF57 homodimerization and led to proteasome-mediated degradation of ORF57 protein. Thus, homodimerization of ORF57 via its C terminus prevents ORF57 from degrading and allows two structure-free N termini of the dimerized ORF57 to work coordinately for host factor interactions, leading to productive KSHV lytic infection and pathogenesis.
IMPORTANCE: KSHV is a human oncogenic virus linked to the development of several malignancies. KSHV-mediated oncogenesis requires both latent and lytic infection. The KSHV ORF57 protein is essential for KSHV lytic replication, as it regulates the expression of viral lytic genes at the posttranscriptional level. This report provides evidence that the structural conformation of the ORF57 protein plays a critical role in regulation of ORF57 stability. Phosphorylation by CKII on the identified serine/threonine residues at the N-terminal unstructured domain of ORF57 prevents its digestion by caspase-7. The C-terminal domain of ORF57, which is rich in α-helices, contributes to homodimerization of ORF57 to prevent proteasome-mediated protein degradation. Elucidation of the ORF57 structure not only enables us to better understand ORF57 stability and functions but also provides an important tool for us to modulate ORF57's activity with the aim to inhibit KSHV lytic replication.

Ebert R, Meissner-Weigl J, Zeck S, et al.
Probenecid as a sensitizer of bisphosphonate-mediated effects in breast cancer cells.
Mol Cancer. 2014; 13:265 [PubMed] Article available free on PMC after 15/09/2015 Related Publications
BACKGROUND: Anti-resorptive bisphosphonates (BP) are used for the treatment of osteoporosis and bone metastases. Clinical studies indicated a benefit in survival and tumor relapse in subpopulations of breast cancer patients receiving zoledronic acid, thus stimulating the debate about its anti-tumor activity. Amino-bisphosphonates in nM concentrations inhibit farnesyl pyrophosphate synthase leading to accumulation of isopentenyl pyrophosphate (IPP) and the ATP/pyrophosphate adduct ApppI, which induces apoptosis in osteoclasts. For anti-tumor effects μM concentrations are needed and a sensitizer for bisphosphonate effects would be beneficial in clinical anti-tumor applications. We hypothesized that enhancing intracellular pyrophosphate accumulation via inhibition of probenecid-sensitive channels and transporters would sensitize tumor cells for bisphosphonates anti-tumor efficacy.
METHOD: MDA-MB-231, T47D and MCF-7 breast cancer cells were treated with BP (zoledronic acid, risedronate, ibandronate, alendronate) and the pyrophosphate channel inhibitors probenecid and novobiocin. We determined cell viability and caspase 3/7 activity (apoptosis), accumulation of IPP and ApppI, expression of ANKH, PANX1, ABCC1, SLC22A11, and the zoledronic acid target gene and tumor-suppressor KLF2.
RESULTS: Treatment of MDA-MB-231 with BP induced caspase 3/7 activity, with zoledronic acid being the most effective. In MCF-7 and T47D either BP markedly suppressed cell viability with only minor effects on apoptosis. Co-treatment with probenecid enhanced BP effects on cell viability, IPP/ApppI accumulation as measurable in MCF-7 and T47D cells, caspase 3/7 activity and target gene expression. Novobiocin co-treatment of MDA-MB-231 yielded identical results on viability and apoptosis compared to probenecid, rendering SLC22A family members as candidate modulators of BP effects, whereas no such evidence was found for ANKH, ABCC1 and PANX1.
CONCLUSIONS: In summary, we demonstrate effects of various bisphosphonates on caspase 3/7 activity, cell viability and expression of tumor suppressor genes in breast cancer cells. Blocking probenecid and novobiocin-sensitive channels and transporters enhances BP anti-tumor effects and renders SLC22A family members as good candidates as BP modulators. Further studies will have to unravel if treatment with such BP-sensitizers translates into preclinical and clinical efficacy.

Lee YJ, Hwang IS, Lee YJ, et al.
Knockdown of Bcl-xL enhances growth-inhibiting and apoptosis-inducing effects of resveratrol and clofarabine in malignant mesothelioma H-2452 cells.
J Korean Med Sci. 2014; 29(11):1464-72 [PubMed] Article available free on PMC after 15/09/2015 Related Publications
Mcl-1 and Bcl-xL, key anti-apoptotic proteins of the Bcl-2 family, have attracted attention as important molecules in the cell survival and drug resistance. In this study, we investigated whether inhibition of Bcl-xL influences cell growth and apoptosis against simultaneous treatment of resveratrol and clofarabine in the human malignant mesothelioma H-2452 cells. Resveratrol and clofarabine decreased Mcl-1 protein levels but had little effect on Bcl-xL levels. In the presence of two compounds, any detectable change in the Mcl-1 mRNA levels was not observed in RT-PCR analysis, whereas pretreatment with the proteasome inhibitor MG132 led to its accumulation to levels far above basal levels. The knockdown of Bcl-xL inhibited cell proliferation with cell accumulation at G2/M phase and the appearance of sub-G0/G1 peak in DNA flow cytometric assay. The suppression of cell growth was accompanied by an increase in the caspase-3/7 activity with the resultant cleavages of procaspase-3 and its substrate poly (ADP-ribose) polymerase, and increased percentage of apoptotic propensities in annexin V binding assay. Collectively, our data represent that the efficacy of resveratrol and clofarabine for apoptosis induction was substantially enhanced by Bcl-xL-lowering strategy in which the simultaneous targeting of Mcl-1 and Bcl-xL could be a more effective strategy for treating malignant mesothelioma.

Ma L, Maruwge W, Strambi A, et al.
SIRT1 and SIRT2 inhibition impairs pediatric soft tissue sarcoma growth.
Cell Death Dis. 2014; 5:e1483 [PubMed] Article available free on PMC after 15/09/2015 Related Publications
Sirtuins are NAD+ dependent deacetylases and/or ADP-ribosyl transferases active on histone and non-histone substrates. The first sirtuin was discovered as a transcriptional repressor of the mating-type-loci (Silent Information Regulator sir2) in the budding yeast, where it was shown to extend yeast lifespan. Seven mammalian sirtuins (SIRT1-7) have been now identified with distinct subcellular localization, enzymatic activities and substrates. These enzymes regulate cellular processes such as metabolism, cell survival, differentiation, DNA repair and they are implicated in the pathogenesis of solid tumors and leukemias. The purpose of the present study was to investigate the role of sirtuin expression, activity and inhibition in the survival of pediatric sarcoma cell lines.We have analyzed the expression of SIRT1 and SIRT2 in a series of pediatric sarcoma tumor cell lines and normal cells, and we have evaluated the activity of the sirtuin inhibitor and p53 activator tenovin-6 (Tv6) in synovial sarcoma and rhabdomyosarcoma cell lines. We show that SIRT1 is overexpressed in synovial sarcoma biopsies and cell lines in comparison with normal mesenchymal cells. Tv6 induced apoptosis as well as impaired autophagy flux. Using siRNA to knock down SIRT1 and SIRT2, we show that the expression of both proteins is crucial for the survival of rhabdomyosarcoma cells and that the loss of SIRT1 expression results in a decreased LC3II expression. Our results show that SIRT1 and SIRT2 expressions are crucial for the survival of synovial sarcomas and rhabdomyosarcomas, and demonstrate that the pharmacological inhibition of sirtuins impairs the autophagy process and induces tumor cell death.

Zhang N, Chu ES, Zhang J, et al.
Peroxisome proliferator activated receptor alpha inhibits hepatocarcinogenesis through mediating NF-κB signaling pathway.
Oncotarget. 2014; 5(18):8330-40 [PubMed] Article available free on PMC after 15/09/2015 Related Publications
Peroxisome proliferator-activated receptor alpha (PPARα) ligands have been reported to suppress cancer growth. However, the role of PPARα in hepatocarcinogenesis remains unclear. We investigated the functional significance of PPARα in HCC. PPARα-knockout (PPARα-/-) mice were more susceptible to diethylnitrosamine (DEN)-induced HCC at 6 months compared with wild-type (WT) littermates (80% versus 43%, P < 0.05). In resected HCCs, TUNEL-positive apoptotic cells were significantly less in PPARα-/- mice than in WT mice (P < 0.01), commensurate with a reduction in cleaved caspase-3 and caspase-7 protein expression. Ki-67 staining showed increased cell proliferation in PPARα-/- mice (P < 0.01), with concomitant up-regulation of cyclin-D1 and down-regulation of p15. Moreover, ectopic expression of PPARα in HCC cells significantly suppressed cell proliferation and induced apoptosis. The anti-tumorigenic function of PPARα was mediated via NF-κB as evidenced by inhibition of NF-κB promoter activity, diminution of phosphor-p65, phosphor-p50 and BCL2 levels, and enhancing IkBα protein. Chromatin immunoprecipitation analysis confirmed PPARαdirectly binds to the IkBα promoter. In conclusion, PPARα deficiency enhances susceptibility to DEN-initiated HCC. PPARα suppresses tumor cell growth by inhibiting cell proliferation and inducing cell apoptosis via direct targeting IκBα and NF-κB signaling pathway.

Chen H, Ma HR, Gao YH, et al.
Isoflavones extracted from chickpea Cicer arietinum L. sprouts induce mitochondria-dependent apoptosis in human breast cancer cells.
Phytother Res. 2015; 29(2):210-9 [PubMed] Related Publications
Isoflavones are important chemical components of the seeds and sprouts of chickpeas. We systematically investigated the effects of isoflavones extracted from chickpea sprouts (ICS) on the human breast cancer cell lines SKBr3 and Michigan Cancer Foundation-7 (MCF-7). 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assays showed that ICS (10-60 µg/mL) significantly inhibited the proliferation of both cell lines in a time-dependent and dose-dependent fashion. Wright-Giemsa staining as well as annexin V-fluorescein isothiocyanate and propidium iodide (Annexin V/PI) staining showed that ICS significantly increased cytoclasis and apoptotic body formation. Quantitative Annexin V/PI assays further showed that the number of apoptotic cells increased in a dose-dependent manner following ICS treatment. Semiquantitative reverse transcription PCR showed that ICS increased the expression of the apoptosis-promoting gene Bcl-2-associated X protein and decreased the expression of the antiapoptotic gene Bcl-2. Western blot analysis showed that treatment of SKBr3 and MCF-7 cells with ICS increased the expression of caspase 7, caspase 9, P53, and P21 in a dose-dependent manner. Flow cytometry assays using the fluorescent probe 3,3'-dihexyloxacarbocyanine iodide showed a dose-dependent decrease in mitochondrial membrane potential following ICS treatment. Treatment using ICS also induced a dose-dependent increase in reactive oxygen species production. This is the first study to demonstrate that ICS may be a chemopreventive or therapeutic agent against breast cancer.

Hu SC, Yu HS, Yen FL, et al.
CXCR7 expression correlates with tumor depth in cutaneous squamous cell carcinoma skin lesions and promotes tumor cell survival through ERK activation.
Exp Dermatol. 2014; 23(12):902-8 [PubMed] Related Publications
The chemokine receptor CXCR7 has been demonstrated to be involved in the development of certain cancers, but its role in cutaneous squamous cell carcinoma (SCC) has not been previously investigated. We seek to determine whether CXCR7 is expressed in human cutaneous SCC skin lesions and SCC cell lines. In addition, we evaluate whether CXCR7 plays a role in SCC cell proliferation, survival and migration and which signalling pathways are involved. Using quantitative RT-PCR to analyse the mRNA expression of 19 different chemokine receptors, we found that CXCR7 was much more highly expressed compared to other chemokine receptors in cutaneous SCC cell lines (HSC-1 and HSC-5). On immunohistochemical staining, CXCR7 was found to be expressed in 70% (28 of 40) of human cutaneous SCC tissue specimens, and its expression correlated with tumor depth >4 mm and cancer stage ≥II. CXCR7 but not CXCR4 protein was expressed on the surface of HSC-1 and HSC-5 cells by flow cytometry. Activation of the CXCR7 receptor by CXCL12 promoted survival of HSC-1 and HSC-5 cells through the ERK pathway, but had no significant effect on cell proliferation or migration. In summary, our findings indicate that CXCR7 is frequently expressed in cutaneous SCC skin lesions and its expression correlates with tumor depth and cancer stage. CXCR7 is the predominant chemokine receptor expressed in SCC cell lines, and activation of CXCR7 by CXCL12 promotes survival of SCC cells through the ERK pathway. These findings provide new insights into the significance of CXCR7 in the pathophysiology of SCC.

Pan J, Zhang Q, Liu Q, et al.
Honokiol inhibits lung tumorigenesis through inhibition of mitochondrial function.
Cancer Prev Res (Phila). 2014; 7(11):1149-59 [PubMed] Related Publications
Honokiol is an important bioactive compound found in the bark of Magnolia tree. It is a nonadipogenic PPARγ agonist and capable of inhibiting the growth of a variety of tumor types both in vitro and in xenograft models. However, to fully appreciate the potential chemopreventive activity of honokiol, a less artificial model system is required. To that end, this study examined the chemopreventive efficacy of honokiol in an initiation model of lung squamous cell carcinoma (SCC). This model system uses the carcinogen N-nitroso-trischloroethylurea (NTCU), which is applied topically, reliably triggering the development of SCC within 24 to 26 weeks. Administration of honokiol significantly reduced the percentage of bronchial that exhibit abnormal lung SCC histology from 24.4% bronchial in control to 11.0% bronchial in honokiol-treated group (P = 0.01) while protecting normal bronchial histology (present in 20.5% of bronchial in control group and 38.5% of bronchial in honokiol-treated group. P = 0.004). P63 staining at the SCC site confirmed the lung SCCs phenotype. In vitro studies revealed that honokiol inhibited lung SCC cells proliferation, arrested cells at the G1-S cell-cycle checkpoint, while also leading to increased apoptosis. Our study showed that interfering with mitochondrial respiration is a novel mechanism by which honokiol changed redox status in the mitochondria, triggered apoptosis, and finally leads to the inhibition of lung SCC. This novel mechanism of targeting mitochondrial suggests honokiol as a potential lung SCC chemopreventive agent.

Park JB, Agnihotri S, Golbourn B, et al.
Transcriptional profiling of GBM invasion genes identifies effective inhibitors of the LIM kinase-Cofilin pathway.
Oncotarget. 2014; 5(19):9382-95 [PubMed] Article available free on PMC after 15/09/2015 Related Publications
Malignant gliomas are highly proliferative and invasive neoplasms where total surgical resection is often impossible and effective local radiation therapy difficult. Consequently, there is a need to develop a greater understanding of the molecular events driving invasion and to identify novel treatment targets. Using microarray analysis comparing normal brain samples and mesenchymal glioblastoma multiforme (GBM), we identified over 140 significant genes involved in cell migration and invasion. The cofilin (CFL) pathway, which disassembles actin filaments, was highly up-regulated compared to normal brain. Up-regulation of LIM domain kinase 1 and 2 (LIMK1/2), that phosphorylates and inactivates cofilin, was confirmed in an additional independent data set comparing normal brain to GBM. We identified and utilized two small molecule inhibitors BMS-5 and Cucurbitacin I directed against the cofilin regulating kinases, LIMK1 and LIMK2, to target this pathway. Significant decreases in cell viability were observed in glioma cells treated with BMS-5 and Cucurbitacin I, while no cytotoxic effects were seen in normal astrocytes that lack LIMK. BMS-5 and Cucurbitacin I promoted increased adhesion in GBM cells, and decreased migration and invasion. Collectively, these data suggest that use of LIMK inhibitors may provide a novel way to target the invasive machinery in GBM.

Yoon TM, Kim SA, Lee DH, et al.
Expression of Livin and the inhibition of tumor progression by Livin silencing in laryngohypopharyngeal cancer.
In Vivo. 2014 Sep-Oct; 28(5):751-9 [PubMed] Related Publications
AIM: To evaluate the expression of Livin in human laryngohypopharyngeal squamous cell carcinoma (LHSCC) and investigate whether Livin-knockdown using small interfering-RNA (siRNA) affects tumor aggressiveness in LHSCC cells.
MATERIALS AND METHODS: Immunohistochemistry, reverse transcription-polymerase chain reaction, western blotting, cell invasion assay, cell migration assay, and cell apoptosis assays were performed to assess the impact of Livin on cancer cell behavior in human LHSCC.
RESULTS: High immunoreactivity of Livin was observed in 22 (36.7%) of the 60 LHSCC tissues relative to adjacent normal mucosa. In the positive-Livin expression group, distant metastasis tended to occur frequently, but the difference was not statistically significant (p=0.06). Livin-knockdown by siRNA induced cell apoptosis through activation of caspase 3, caspase 7, and poly ADP ribose polymerase in LHSCC cells. Livin-knockdown also resulted in significantly reduced cell invasion and migration in LHSCC cells.
CONCLUSION: siRNA-mediated silencing of Livin may be associated with the reversal of invasive capacity in LHSCC.

Alpay K, Farshchian M, Tuomela J, et al.
Inhibition of c-Abl kinase activity renders cancer cells highly sensitive to mitoxantrone.
PLoS One. 2014; 9(8):e105526 [PubMed] Article available free on PMC after 15/09/2015 Related Publications
Although c-Abl has increasingly emerged as a key player in the DNA damage response, its role in this context is far from clear. We studied the effect of inhibition of c-Abl kinase activity by imatinib with chemotherapy drugs and found a striking difference in cell survival after combined mitoxantrone (MX) and imatinib treatment compared to a panel of other chemotherapy drugs. The combinatory treatment induced apoptosis in HeLa cells and other cancer cell lines but not in primary fibroblasts. The difference in MX and doxorubicin was related to significant augmentation of DNA damage. Transcriptionally active p53 accumulated in cells in which human papillomavirus E6 normally degrades p53. The combination treatment resulted in caspase activation and apoptosis, but this effect did not depend on either p53 or p73 activity. Despite increased p53 activity, the cells arrested in G2 phase became defective in this checkpoint, allowing cell cycle progression. The effect after MX treatment depended partially on c-Abl: Short interfering RNA knockdown of c-Abl rendered HeLa cells less sensitive to MX. The effect of imatinib was decreased by c-Abl siRNA suggesting a role for catalytically inactive c-Abl in the death cascade. These findings indicate that MX has a unique cytotoxic effect when the kinase activity of c-Abl is inhibited. The treatment results in increased DNA damage and c-Abl-dependent apoptosis, which may offer new possibilities for potentiation of cancer chemotherapy.

Mirzaei MR, Najafi A, Arababadi MK, et al.
Altered expression of apoptotic genes in response to OCT4B1 suppression in human tumor cell lines.
Tumour Biol. 2014; 35(10):9999-10009 [PubMed] Related Publications
OCT4B1 is a newly discovered spliced variant of OCT4 which is primarily expressed in pluripotent and tumor cells. Based on our previous studies, OCT4B1 is significantly overexpressed in tumors, where it endows an anti-apoptotic property to tumor cells. However, the mechanism by which OCT4B1 regulates the apoptotic pathway is not yet elucidated. Here, we investigated the effects of OCT4B1 suppression on the expression alteration of 84 genes involved in apoptotic pathway. The AGS (gastric adenocarcinoma), 5637 (bladder tumor), and U-87MG (brain tumor) cell lines were transfected with OCT4B1 or irrelevant siRNAs. The expression level of apoptotic genes was then quantified using a human apoptosis panel-PCR kit. Our data revealed an almost similar pattern of alteration in the expression profile of apoptotic genes in all three studied cell lines, following OCT4B1 suppression. In general, the expression of more than 54 apoptotic genes (64 % of arrayed genes) showed significant changes. Among these, some up-regulated (CIDEA, CIDEB, TNFRSF1A, TNFRSF21, TNFRSF11B, TNFRSF10B, and CASP7) and down-regulated (BCL2, BCL2L11, TP73, TP53, BAD, TRAF3, TRAF2, BRAF, BNIP3L, BFAR, and BAX) genes had on average more than tenfold gene expression alteration in all three examined cell lines. With some minor exceptions, suppression of OCT4B1 caused upregulation of pro-apoptotic and down-regulation of anti-apoptotic genes in transfected tumor cells. Uncovering OCT4B1 down-stream targets could further elucidate its part in tumorigenesis, and could lead to finding a new approach to combat cancer, based on targeting OCT4B1.

Yong FL, Wang CW, Roslani AC, Law CW
The involvement of miR-23a/APAF1 regulation axis in colorectal cancer.
Int J Mol Sci. 2014; 15(7):11713-29 [PubMed] Article available free on PMC after 15/09/2015 Related Publications
Recent advances in microRNAome have made microRNAs (miRNAs) a compelling novel class of biomarker in cancer biology. In the present study, the role of miR-23a in the carcinogenesis of colorectal cancer (CRC) was investigated. Cell viability, apoptosis, and caspase 3/7 activation analyses were conducted to determine the potentiality of apoptosis resistance function of miR-23a in CRC. Luciferase assay was performed to verify a putative target site of miR-23a in the 3'-UTR of apoptosis protease activating factor 1 (APAF1) mRNA. The expression levels of miR-23a and APAF1 in CRC cell lines (SW480 and SW620) and clinical samples were assessed using reverse transcription-quantitative real-time PCR (RT-qPCR) and Western blot. We found that the inhibition of miR-23a in SW480 and SW620 cell lines resulted in significant reduction of cell viability and promotion of cell apoptosis. Moreover, miR-23a up-regulation was coupled with APAF1 down-regulation in CRC tissue samples. Taken together, miR-23a was identified to regulate apoptosis in CRC. Our study highlights the potential application of miR-23a/APAF1 regulation axis in miRNA-based therapy and prognostication.

Vazquez-Ortiz G, Chisholm C, Xu X, et al.
Drug repurposing screen identifies lestaurtinib amplifies the ability of the poly (ADP-ribose) polymerase 1 inhibitor AG14361 to kill breast cancer associated gene-1 mutant and wild type breast cancer cells.
Breast Cancer Res. 2014; 16(3):R67 [PubMed] Article available free on PMC after 15/09/2015 Related Publications
INTRODUCTION: Breast cancer is a devastating disease that results in approximately 40,000 deaths each year in the USA. Current drug screening and chemopreventatitive methods are suboptimal, due in part to the poor specificity of compounds for cancer cells. Poly (ADP-ribose) polymerase 1 (PARP1) inhibitor (PARPi)-mediated therapy is a promising approach for familial breast cancers caused by mutations of breast cancer-associated gene-1 and -2 (BRCA1/2), yet drug resistance frequently occurs during the treatment. Moreover, PARPis exhibit very little effect on cancers that are proficient for DNA repair and clinical efficacy for PARPis as single-agent therapies has yet to be illustrated.
METHODS: Using a quantitative high-throughput screening approach, we screened a library containing 2,816 drugs, most of which are approved for human or animal use by the Food and Drug Administration (FDA) or other countries, to identify compounds that sensitize breast cancer cells to PARPi. After initial screening, we performed further cellular and molecular analysis on lestaurtinib, which is an orally bioavailable multikinase inhibitor and has been used in clinical trials for myeloproliferative disorders and acute myelogenous leukemia.
RESULTS: Our study indicated that lestaurtinib is highly potent against breast cancers as a mono-treatment agent. It also strongly enhanced the activity of the potent PARPi AG14361 on breast cancer cell growth both in vitro and in vivo conditions. The inhibition of cancer growth is measured by increased apoptosis and reduced cell proliferation. Consistent with this, the treatment results in activation of caspase 3/7, and accumulation of cells in the G2 phase of the cell cycle, irrespective of their BRCA1 status. Finally, we demonstrated that AG14361 inhibits NF-κB signaling, which is further enhanced by lestaurtinib treatment.
CONCLUSIONS: Lestaurtinib amplifies the ability of the PARP1 inhibitor AG14361 to kill BRCA1 mutant and wild-type breast cancer cells, at least in part, by inhibiting NF-κB signaling. Each of these drugs has been approved for clinical trials for several different cancers, thus, their combination treatment should be applicable for a breast cancer trial in the future.

Zhang L, Dong Y, Zhu N, et al.
microRNA-139-5p exerts tumor suppressor function by targeting NOTCH1 in colorectal cancer.
Mol Cancer. 2014; 13:124 [PubMed] Article available free on PMC after 15/09/2015 Related Publications
BACKGROUND: miR-139-5p was identified to be significantly down-regulated in colon tumor tissues by miRNA array. We aimed to clarify its biological function, molecular mechanisms and direct target gene in colorectal cancer (CRC).
METHODS: The biological function of miR-139-5p was examined by cell growth, cell cycle and apoptosis analysis in vitro and in vivo. miR-139-5p target gene and signaling pathway was identified by luciferase activity assay and western blot.
RESULTS: miR-139-5p was significantly down-regulated in primary tumor tissues (P < 0.0001). Ectopic expression of miR-139-5p in colon cancer cell lines significantly suppressed cell growth as evidenced by cell viability assay (P < 0.001) and colony formation assay (P < 0.01) and in xenograft tumor growth in nude mice (P < 0.01). miR-139-5p induced apoptosis (P < 0.01), concomitantly with up-regulation of key apoptosis genes including cleaved caspase-8, caspase-3, caspase-7 and PARP. miR-139-5p also caused cell cycle arrest in G0/G1 phase (P < 0.01), with upregulation of key G0/G1 phase regulators p21Cip1/Waf1 and p27Kip1. Moreover, miR-139-5p inhibited cellular migration (P < 0.001) and invasiveness (P < 0.001) through the inhibition of matrix metalloproteinases (MMP)7 and MMP9. Oncogene NOTCH1 was revealed to be a putative target of miR-139-5p, which was inversely correlated with miR-139-5p expression (r = -0.3862, P = 0.0002).
CONCLUSIONS: miR-139-5p plays a pivotal role in colon cancer through inhibiting cell proliferation, metastasis, and promoting apoptosis and cell cycle arrest by targeting oncogenic NOTCH1.

Dragoi AM, Swiss R, Gao B, Agaisse H
Novel strategies to enforce an epithelial phenotype in mesenchymal cells.
Cancer Res. 2014; 74(14):3659-72 [PubMed] Article available free on PMC after 15/09/2015 Related Publications
E-cadherin downregulation in cancer cells is associated with epithelial-to-mesenchymal transition (EMT) and metastatic prowess, but the underlying mechanisms are incompletely characterized. In this study, we probed E-cadherin expression at the plasma membrane as a functional assay to identify genes involved in E-cadherin downregulation. The assay was based on the E-cadherin-dependent invasion properties of the intracellular pathogen Listeria monocytogenes. On the basis of a functional readout, automated microscopy and computer-assisted image analysis were used to screen siRNAs targeting 7,000 human genes. The validity of the screen was supported by its definition of several known regulators of E-cadherin expression, including ZEB1, HDAC1, and MMP14. We identified three new regulators (FLASH, CASP7, and PCGF1), the silencing of which was sufficient to restore high levels of E-cadherin transcription. In addition, we identified two new regulators (FBXL5 and CAV2), the silencing of which was sufficient to increase E-cadherin expression at a posttranscriptional level. FLASH silencing regulated the expression of E-cadherin and other ZEB1-dependent genes, through posttranscriptional regulation of ZEB1, but it also regulated the expression of numerous ZEB1-independent genes with functions predicted to contribute to a restoration of the epithelial phenotype. Finally, we also report the identification of siRNA duplexes that potently restored the epithelial phenotype by mimicking the activity of known and putative microRNAs. Our findings suggest new ways to enforce epithelial phenotypes as a general strategy to treat cancer by blocking invasive and metastatic phenotypes associated with EMT.

Wang X, Lai P, Zhang Z, et al.
Targeted inhibition of mTORC2 prevents osteosarcoma cell migration and promotes apoptosis.
Oncol Rep. 2014; 32(1):382-8 [PubMed] Related Publications
Dysregulation of mammalian target of rapamycin (mTOR) signaling often occurs in many human malignant diseases, making it a potential target in the treatment of cancer. However, the effects of specifically targeted inhibition of mammalian target of rapamycin complex 2 (mTORC2) on osteosarcoma have not been reported. Three types of osteosarcoma cell lines (MG63/U2OS/Saos-2) were used in this study. Inhibition of mTORC2 was carried out by mTOR inhibitor PP242 and targeted siRNA. The anti-migration effect was evaluated through wound healing and Transwell assays. Osteosarcoma cells were either treated independently by inhibition of mTORC2 or in combination with cisplatin, and apoptosis was evaluated by staining with propidium iodide; PARP and caspase 7 expression levels were evaluated. Targeting of mTORC2 either by kinase inhibitor or rictor knockdown promoted cisplatin-induced apoptosis, but inhibition of mTORC1 either by rapamycin or raptor knockdown did not promote cisplatin-induced apoptosis. Furthermore, inhibition of mTORC2 but not mTORC1 effectively prevented osteosarcoma cell migration. These results suggest that agents that inhibit mTORC2 have advantages over mTORC1 inhibitors in the treatment of osteosarcoma. The present study provides a strong rationale for testing the use of mTORC1/2 inhibitors or the combination of mTORC1/2 inhibitors and cisplatin in the treatment of osteosarcoma.

Liu G, Li DZ, Jiang CS, Wang W
Transduction motif analysis of gastric cancer based on a human signaling network.
Braz J Med Biol Res. 2014; 47(5):369-75 [PubMed] Article available free on PMC after 15/09/2015 Related Publications
To investigate signal regulation models of gastric cancer, databases and literature were used to construct the signaling network in humans. Topological characteristics of the network were analyzed by CytoScape. After marking gastric cancer-related genes extracted from the CancerResource, GeneRIF, and COSMIC databases, the FANMOD software was used for the mining of gastric cancer-related motifs in a network with three vertices. The significant motif difference method was adopted to identify significantly different motifs in the normal and cancer states. Finally, we conducted a series of analyses of the significantly different motifs, including gene ontology, function annotation of genes, and model classification. A human signaling network was constructed, with 1643 nodes and 5089 regulating interactions. The network was configured to have the characteristics of other biological networks. There were 57,942 motifs marked with gastric cancer-related genes out of a total of 69,492 motifs, and 264 motifs were selected as significantly different motifs by calculating the significant motif difference (SMD) scores. Genes in significantly different motifs were mainly enriched in functions associated with cancer genesis, such as regulation of cell death, amino acid phosphorylation of proteins, and intracellular signaling cascades. The top five significantly different motifs were mainly cascade and positive feedback types. Almost all genes in the five motifs were cancer related, including EPOR, MAPK14, BCL2L1, KRT18, PTPN6, CASP3, TGFBR2, AR, and CASP7. The development of cancer might be curbed by inhibiting signal transductions upstream and downstream of the selected motifs.

Wang S, Wang L, Shi Z, et al.
Evodiamine synergizes with doxorubicin in the treatment of chemoresistant human breast cancer without inhibiting P-glycoprotein.
PLoS One. 2014; 9(5):e97512 [PubMed] Article available free on PMC after 15/09/2015 Related Publications
Drug resistance is one of the main hurdles for the successful treatment of breast cancer. The synchronous targeting of apoptosis resistance and survival signal transduction pathways may be a promising approach to overcome drug resistance. In this study, we determined that evodiamine (EVO), a major constituent of the Chinese herbal medicine Evodiae Fructus, could induce apoptosis of doxorubicin (DOX)-sensitive MCF-7 and DOX-resistant MCF-7/ADR cells in a caspase-dependent manner, as confirmed by significant increases of cleaved poly(ADP-ribose) polymerase (PARP), caspase-7/9, and caspase activities. Notably, the reversed phenomenon of apoptosis resistance by EVO might be attributed to its ability to inhibit the Ras/MEK/ERK pathway and the expression of inhibitors of apoptosis (IAPs). Furthermore, our results indicated that EVO enhanced the apoptotic action of DOX by inhibiting the Ras/MEK/ERK cascade and the expression of IAPs without inhibiting the expression and activity of P-glycoprotein (P-gp). Taken together, our data indicate that EVO, a natural product, may be useful applied alone or in combination with DOX for the treatment of resistant breast cancer.

Chuang TD, Khorram O
miR-200c regulates IL8 expression by targeting IKBKB: a potential mediator of inflammation in leiomyoma pathogenesis.
PLoS One. 2014; 9(4):e95370 [PubMed] Article available free on PMC after 15/09/2015 Related Publications
We have previously reported that leiomyoma expressed lower levels of miR-200c and elevated IL8 as compared to paired myometrium. Here we addressed the regulatory functions of miR-200c on the expression of inflammatory mediators and cellular viability using leiomyomas and paired myometrium and their isolated primary smooth muscle cells. Our results indicated that gain-of function or knockdown of miR-200c in leiomyoma smooth muscle cells (LSMC) regulated IL8 mRNA and protein expression through direct targeting of IKBKB and alteration of NF-kB activity. Additionally, leiomyoma expressed higher levels of phosphorylated IKBKB with no significant difference in the level of IKBKB mRNA and protein as compared to matched myometrium. Gain-of function of miR-200c in LSMC resulted in decreased IkBα phosphorylation and p65 nuclear translocation, which led to decreased p65 transcriptional activity of IL8 promoter, and increased caspase 3/7 activity which was not reversible following IL8 restoration. Collectively, our results suggest that NF-κB signaling pathway is a target of miR-200c regulatory function, and low level of miR-200c expression in leiomyoma by transcriptional regulation of inflammatory mediators such as IL8, in part account for development of leiomyomas.

Garimella SV, Gehlhaus K, Dine JL, et al.
Identification of novel molecular regulators of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL)-induced apoptosis in breast cancer cells by RNAi screening.
Breast Cancer Res. 2014; 16(2):R41 [PubMed] Article available free on PMC after 15/09/2015 Related Publications
INTRODUCTION: Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) binds to its receptors, TRAIL-receptor 1 (TRAIL-R1) and TRAIL-receptor 2 (TRAIL-R2), leading to apoptosis by activation of caspase-8 and the downstream executioner caspases, caspase-3 and caspase-7 (caspase-3/7). Triple-negative breast cancer (TNBC) cell lines with a mesenchymal phenotype are sensitive to TRAIL, whereas other breast cancer cell lines are resistant. The underlying mechanisms that control TRAIL sensitivity in breast cancer cells are not well understood. Here, we performed small interfering RNA (siRNA) screens to identify molecular regulators of the TRAIL pathway in breast cancer cells.
METHODS: We conducted siRNA screens of the human kinome (691 genes), phosphatome (320 genes), and about 300 additional genes in the mesenchymal TNBC cell line MB231. Forty-eight hours after transfection of siRNA, parallel screens measuring caspase-8 activity, caspase-3/7 activity, or cell viability were conducted in the absence or presence of TRAIL for each siRNA, relative to a negative control siRNA (siNeg). A subset of genes was screened in cell lines representing epithelial TNBC (MB468), HER2-amplified breast cancer (SKBR3), and estrogen receptor-positive breast cancer (T47D). Selected putative negative regulators of the TRAIL pathway were studied by using small-molecule inhibitors.
RESULTS: The primary screens in MB231 identified 150 genes, including 83 kinases, 4 phosphatases, and 63 nonkinases, as potential negative regulators of TRAIL. The identified genes are involved in many critical cell processes, including apoptosis, growth factor-receptor signaling, cell-cycle regulation, transcriptional regulation, and DNA repair. Gene-network analysis identified four genes (PDPK1, IKBKB, SRC, and BCL2L1) that formed key nodes within the interaction network of negative regulators. A secondary screen of a subset of the genes identified in additional cell lines representing different breast cancer subtypes and sensitivities to TRAIL validated and extended these findings. Further, we confirmed that small-molecule inhibition of SRC or BCL2L1, in combination with TRAIL, sensitizes breast cancer cells to TRAIL-induced apoptosis, including cell lines resistant to TRAIL-induced cytotoxicity.
CONCLUSIONS: These data identify novel molecular regulators of TRAIL-induced apoptosis in breast cancer cells and suggest strategies for the enhanced application of TRAIL as a therapy for breast cancer.

Ding X, Zhang B, Pei Q, et al.
Triptolide induces apoptotic cell death of human cholangiocarcinoma cells through inhibition of myeloid cell leukemia-1.
BMC Cancer. 2014; 14:271 [PubMed] Article available free on PMC after 15/09/2015 Related Publications
BACKGROUND: Cholangiocarcinoma (CCA), a devastating neoplasm, is highly resistant to current chemotherapies. CCA cells frequently overexpress the antiapoptotic protein myeloid cell leukemia-1(Mcl-1), which is responsible for its extraordinary ability to evade cell death. Triptolide, a bioactive ingredient extracted from Chinese medicinal plant, has been shown to inhibit cell proliferation and induce apoptosis in several cancers.
METHODS: CCK-8 assay was performed to detect cell survival rate in vitro. DAPI staining and Flow cytometry were used to analyze apoptosis. Western blot was performed to determine the expression levels of caspase-3, caspase-7, caspase-9, PARP, and Mcl-1. Quantitative real-time PCR and immunofluorescence were used to detect the expression levels of Mcl-1. The nude mice xenograft model was used to evaluate the antitumor effect of triptolide in vivo.
RESULTS: Triptolide reduced cell viability in cholangiocarcinoma cell lines in a dose- and time-dependent manner, with IC50 values of 12.6 ± 0.6 nM, 20.5 ± 4.2 nM, and 18.5 ± 0.7 nM at 48 h for HuCCT1, QBC939, and FRH0201 respectively. Triptolide induced apoptosis in CCA cell lines in part through mitochondrial pathway. Using quantitative real-time PCR, western blot and immunofluorescence, we have shown that triptolide downregulates Mcl-1 mRNA and protein levels. Furthermore, triptolide inhibited the CCA growth in vivo.
CONCLUSIONS: Triptolide has profound antitumor effect on CCA, probably by inducing apoptosis through inhibition of Mcl-1. Triptolide would be a promising therapeutic agent for CCA.

Chang YC, Hsu YC, Liu CL, et al.
Local anesthetics induce apoptosis in human thyroid cancer cells through the mitogen-activated protein kinase pathway.
PLoS One. 2014; 9(2):e89563 [PubMed] Article available free on PMC after 15/09/2015 Related Publications
Local anesthetics are frequently used in fine-needle aspiration of thyroid lesions and locoregional control of persistent or recurrent thyroid cancer. Recent evidence suggests that local anesthetics have a broad spectrum of effects including inhibition of cell proliferation and induction of apoptosis in neuronal and other types of cells. In this study, we demonstrated that treatment with lidocaine and bupivacaine resulted in decreased cell viability and colony formation of both 8505C and K1 cells in a dose-dependent manner. Lidocaine and bupivacaine induced apoptosis, and necrosis in high concentrations, as determined by flow cytometry. Lidocaine and bupivacaine caused disruption of mitochondrial membrane potential and release of cytochrome c, accompanied by activation of caspase 3 and 7, PARP cleavage, and induction of a higher ratio of Bax/Bcl-2. Based on microarray and pathway analysis, apoptosis is the prominent transcriptional change common to lidocaine and bupivacaine treatment. Furthermore, lidocaine and bupivacaine attenuated extracellular signal-regulated kinase 1/2 (ERK1/2) activity and induced activation of p38 mitogen-activated protein kinase (MAPK) and c-jun N-terminal kinase. Pharmacological inhibitors of MAPK/ERK kinase and p38 MAPK suppressed caspase 3 activation and PARP cleavage. Taken together, our results for the first time demonstrate the cytotoxic effects of local anesthetics on thyroid cancer cells and implicate the MAPK pathways as an important mechanism. Our findings have potential clinical relevance in that the use of local anesthetics may confer previously unrecognized benefits in the management of patients with thyroid cancer.

Ishaq M, Kumar S, Varinli H, et al.
Atmospheric gas plasma-induced ROS production activates TNF-ASK1 pathway for the induction of melanoma cancer cell apoptosis.
Mol Biol Cell. 2014; 25(9):1523-31 [PubMed] Article available free on PMC after 15/09/2015 Related Publications
Atmospheric gas plasmas (AGPs) are able to selectively induce apoptosis in cancer cells, offering a promising alternative to conventional therapies that have unwanted side effects such as drug resistance and toxicity. However, the mechanism of AGP-induced cancer cell death is unknown. In this study, AGP is shown to up-regulate intracellular reactive oxygen species (ROS) levels and induce apoptosis in melanoma but not normal melanocyte cells. By screening genes involved in apoptosis, we identify tumor necrosis factor (TNF)-family members as the most differentially expressed cellular genes upon AGP treatment of melanoma cells. TNF receptor 1 (TNFR1) antagonist-neutralizing antibody specifically inhibits AGP-induced apoptosis signal, regulating apoptosis signal-regulating kinase 1 (ASK1) activity and subsequent ASK1-dependent apoptosis. Treatment of cells with intracellular ROS scavenger N-acetyl-l-cysteine also inhibits AGP-induced activation of ASK1, as well as apoptosis. Moreover, depletion of intracellular ASK1 reduces the level of AGP-induced oxidative stress and apoptosis. The evidence for TNF-signaling dependence of ASK1-mediated apoptosis suggests possible mechanisms for AGP activation and regulation of apoptosis-signaling pathways in tumor cells.

Nikpour M, Emadi-Baygi M, Fischer U, et al.
MTDH/AEG-1 contributes to central features of the neoplastic phenotype in bladder cancer.
Urol Oncol. 2014; 32(5):670-7 [PubMed] Related Publications
OBJECTIVES: Carcinoma of the bladder is the fifth most common cancer whose incidence continues to rise. MTDH/AEG-1 is associated with the initiation and progression of many cancers including breast, hepatocellular, ovarian, and colorectal carcinomas. However, the expression and functional importance of MTDH/AEG-1 in bladder cancer remains unknown. The present study was aimed at exploring the functional role of MTDH/AEG-1 in selected bladder cancer cell lines.
METHODS AND MATERIALS: The relative expression of MTDH/AEG-1 was assessed by real-time quantitative reverse transcription-polymerase chain reaction in several human bladder cancer cell lines as well as cancerous and benign bladder tissues. Then, expression of MTDH/AEG-1 in RT112 and 647V bladder cancer cell lines was knocked down by an RNA interference strategy. Cell viability and apoptosis were determined after treatment with specific interfering RNA. Potential effects of MTDG/AEG-1 specific interfering RNA on the cell cycle were investigated by flow cytometry. We also performed anchorage-independent growth and wound-healing assays to study MTDH/AEG-1 function.
RESULTS: Down-regulation of MTDH/AEG-1 did not significantly affect the cell cycle distribution but rather reduced cell viability via apoptosis, as evidenced by increased annexin V staining and caspase 3/7 activities as well as mitochondrial potential disruption. Of note, serum starvation did not exacerbate the effects of MTDH/AEG-1 knockdown. Furthermore, MTDH/AEG-1 down-regulation significantly decreased anchorage-independent growth and migration of bladder carcinoma cells.
CONCLUSION: Overexpression of MTDH/AEG-1 contributes to the neoplastic phenotype of bladder cancer cells by promoting survival, clonogenicity, and migration.

Zeng L, Kang C, Di C, et al.
The adherens junction-associated protein 1 is a negative transcriptional regulator of MAGEA2, which potentiates temozolomide-induced apoptosis in GBM.
Int J Oncol. 2014; 44(4):1243-51 [PubMed] Related Publications
Previous studies identified the frequent loss of adherens junction-associated protein 1 (AJAP1) expression in glioblastoma (GBM) and its correlation with worse survival. AJAP1 may suppress glioma cell migration, which plays an important role in tumor progression in malignant gliomas such as GBM. However, the role of AJAP1 in cell cycle arrest or apoptosis and resistance to chemotherapy remains unclear. Based on microarray screening results, quantitative PCR and luciferase plasmid reporter constructs were used to evaluate the possible regulatory role of AJAP1 on MAGEA2 expression and function. Cell death assays, TUNEL and other markers of apoptosis were utilized to detect cell apoptosis. Restoration of AJAP1 expression in glioma cells was analyzed after temozolomide exposure. AJAP1 suppressed the expression of MAGEA2 and inhibited the transcriptional activity of MAGEA2 in glioma cells. As AJAP1 expression decreased MAGEA2 protein expression apoptosis increased moderately. Consistent with increased cell death, the induced loss of MAGEA2 expression correlated with increased caspase 3/7 activity, BCL2/BAX ratio and TUNEL signal. AJAP1 expression enhanced cell death in the presence of temozolomide. This study suggests AJAP1 may also function as a pro-apoptotic factor and potentiate cell death by temozolomide in glioma cells. This effect may be partially explained by AJAP1-mediated gene regulation of MAGEA2.

Won YS, Lee JH, Kwon SJ, et al.
α-Mangostin-induced apoptosis is mediated by estrogen receptor α in human breast cancer cells.
Food Chem Toxicol. 2014; 66:158-65 [PubMed] Related Publications
In this study, we evaluated the effects of α-mangostin on cell growth inhibition and induction of apoptosis in MCF-7 ERα-positive human breast cancer cells. Our results showed that α-mangostin inhibited MCF-7 cell proliferation whereas ERα-negative MDA-MB-231 cells were less sensitive to the agent. Additionally, α-mangostin effectively induced apoptosis as evidenced by the appearance of apoptotic nuclei observed with Hoechst 33258 staining and evaluation of sub-G1 DNA contents by flow cytometry. α-Mangostin also activated caspases-8, -9, and -7; increased the protein levels of Bax, p53, and cytosolic cytochrome c; and induced PARP cleavage while reducing Bid and Bcl-2 protein expression. In addition, apoptosis-inducing factor (AIF) was transported from mitochondria to the cytosol after α-mangostin treatment. α-mangostin also induced apoptosis in 17-β-estradiol (E2)-stimulated MCF-7 cells in parallel with the non-stimulated cells. Moreover, treatment with 10μM α-mangostin for 48h specifically decreased the expression of ERα and pS2, an estrogen-responsive gene, in MCF-7 cells. Furthermore, knockdown of ERα expression in MCF-7 cells with siRNA attenuated α-mangostin-induced cell growth inhibition and caspase-7 activation. These results suggest that ERα is required for α-mangostin-induced growth inhibition and apoptosis in human breast cancer cells. Therefore, α-mangostin may be used to prevent and treat of ER-positive breast cancer.

Connor CA, Adriaens M, Pierini R, et al.
Procyanidin induces apoptosis of esophageal adenocarcinoma cells via JNK activation of c-Jun.
Nutr Cancer. 2014; 66(2):335-41 [PubMed] Related Publications
Procyanidins are polymeric flavanols found in fruits and vegetables and have shown anticarcinogenic/chemopreventive properties. We previously showed that oligomeric procyanidin extracted from apples induced cell cycle arrest and apoptosis in esophageal adenocarcinoma (OA) cells. To understand the mechanism of action, we determined transcriptomic changes induced by procyanidin in OA cells. Pathway analysis implicated mitogen-activated protein kinase signaling pathways in eliciting these responses. Procyanidin induced the activation of JNK and p38 and the phosphorylation and expression of c-Jun. Inhibition of JNK but not p38 kinase activity prevented the procyanidin-induced phosphorylation and expression of c-Jun. Knockdown of the expression of JNK1, JNK2, or JUN diminished procyanidin-induced effects on cell proliferation and apoptosis. c-Jun is a component of the transcription factor AP-1 and AP-1 binding sites are overrepresented in the promoters of procyanidin-induced genes. This indicates that JNK activation of c-Jun by procyanidin leads to the induction of apoptosis of OA cells and suggests a role for a c-Jun-mediated transcriptional program. These data provide a mechanistic understanding of how procyanidin specifically targets a distinct pathway involved in the induction of apoptosis in OA cells and will inform future studies investigating its use as a chemopreventive/therapeutic agent.

Mas-Oliva J, Navarro-Vidal E, Tapia-Vieyra JV
ARP2, a novel pro-apoptotic protein expressed in epithelial prostate cancer LNCaP cells and epithelial ovary CHO transformed cells.
PLoS One. 2014; 9(1):e86089 [PubMed] Article available free on PMC after 15/09/2015 Related Publications
Neoplastic epithelial cells generate the most aggressive types of cancers such as those located in the lung, breast, colon, prostate and ovary. During advanced stages of prostate cancer, epithelial cells are associated to the appearance of androgen-independent tumors, an apoptotic-resistant phenotype that ultimately overgrows and promotes metastatic events. We have previously identified and electrophysiologically characterized a novel Ca(2+)-permeable channel activated during apoptosis in the androgen-independent prostate epithelial cancer cell line, LNCaP. In addition, we reported for the first time the cloning and characterization of this channel-like molecule named apoptosis regulated protein 2 (ARP2) associated to a lethal influx of Ca(2+) in Xenopus oocytes. In the present study, LNCaP cells and Chinese hamster ovary cells (CHO cell line) transfected with arp2-cDNA are induced to undergo apoptosis showing an important impact on cell viability and activation of caspases 3 and 7 when compared to serum deprived grown cells and ionomycin treated cells. The subcellular localization of ARP2 in CHO cells undergoing apoptosis was studied using confocal microscopy. While apoptosis progresses, ARP2 initially localized in the peri-nuclear region of cells migrates with time towards the plasma membrane region. Based on the present results and those of our previous studies, the fact that ARP2 constitutes a novel cation channel is supported. Therefore, ARP2 becomes a valuable target to modulate the influx and concentration of calcium in the cytoplasm of epithelial cancer cells showing an apoptotic-resistant phenotype during the onset of an apoptotic event.

Mezzanotte L, An N, Mol IM, et al.
A new multicolor bioluminescence imaging platform to investigate NF-κB activity and apoptosis in human breast cancer cells.
PLoS One. 2014; 9(1):e85550 [PubMed] Article available free on PMC after 15/09/2015 Related Publications
BACKGROUND: Evaluation of novel drugs for clinical development depends on screening technologies and informative preclinical models. Here we developed a multicolor bioluminescent imaging platform to simultaneously investigate transcription factor NF-κB signaling and apoptosis.
METHODS: The human breast cancer cell line (MDA-MB-231) was genetically modified to express green, red and blue light emitting luciferases to monitor cell number and viability, NF-κB promoter activity and to perform specific cell sorting and detection, respectively. The pro-luciferin substrate Z-DEVD-animoluciferin was employed to determine apoptotic caspase 3/7 activity. We used the cell line for the in vitro evaluation of natural compounds and in vivo optical imaging of tumor necrosis factor TNFα-induced NF-κB activation.
RESULTS: Celastrol, resveratrol, sulphoraphane and curcumin inhibited the NF-κB promoter activity significantly and in a dose dependent manner. All compounds except resveratrol induced caspase 3/7 dependent apoptosis. Multicolor bioluminescence in vivo imaging allowed the investigation of tumor growth and NF-κB induction in a mouse model of breast cancer.
CONCLUSION: Our new method provides an imaging platform for the identification, validation, screening and optimization of compounds acting on NF-κB signaling and apoptosis both in vitro and in vivo.

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