BACKGROUND: The prognostic significance of stress-induced protein 1 (STIP1) expression in human cancer has been explored in several studies, however, consensus has not been reached. This meta-analysis aimed to summarize the prognostic value of STIP1 expression in cancer.
METHODS: Four common databases were searched to seek relevant studies. The meta-analysis was performed to explore the prognostic value of STIP1 expression in overall survival (OS) and clinicopathological parameters in cancer.
RESULTS: Nine studies containing 1417 cancer patients were finally included into the meta-analysis. The results showed the prevalence of high STIP1 expression was 0.50 in patients with cancer. Compared to patients with low expression of STIP1, patients with high STIP1 expression tended to have shorter OS [hazard ratio (HR) = 2.15, 95% confidence interval (CI) = 1.68-2.76, P < 0.01]. The subgroup analysis also observed the association between high STIP1 expression and shorter OS in gastrointestinal cancer (HR = 2.02, 95%CI = 1.52-2.69, P < 0.01). The online database cross-validation containing 9502 patients also indicated high STIP1 expression predicted shorter OS (HR = 1.40, P < 0.01) and disease-free survival (DFS) (HR = 1.30, P < 0.01) compared with low STIP1 expression in cancer. Besides, high STIP1 expression was obviously related to earlier lymph node metastasis (P < 0.01) and more advanced clinical stage (P < 0.01) compared with low STIP1 expression in cancer.
CONCLUSION: High STIP1 expression was significantly associated with shorter OS, earlier lymph node metastasis and more advanced clinical stage compared with low STIP1 expression in cancer. Therefore, STIP1 expression might be used as a prognostic biomarker for cancer treatment.

Stress-induced phosphoprotein 1 (STIP1) is an adaptor protein that bridges HSP70 and HSP90 folding and a secretory protein that regulates malignant tumor progression. The aim of the present study was to demonstrate the clinicopathological significance and prognostic role of STIP1 in colorectal cancer (CRC). We used data from The Cancer Genome Atlas (TCGA) to analyze STIP1 expression in CRC and utilized 8 pairs of fresh-frozen tissue samples to investigate STIP1 expression in CRC tissues and adjacent normal tissues using quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot assays. We also used immunohistochemical staining to detect STIP1 expression in 144 formalin-fixed, paraffin-embedded (FFPE) CRC tissue samples and determine the clinical significance of STIP1 expression in CRC. The results of bioinformatics analysis, qRT-PCR, and Western blot showed that STIP1 expression was higher in CRC tissues than in adjacent normal tissues. High STIP1 expression was significantly correlated with advanced T stage (P = .01), N stage (P = .001), M stage (P < .001), and TNM stage (P < .001). Moreover, Kaplan-Meier analyses indicated that higher STIP1 expression predicted a worse prognosis in patients with CRC, and Cox regression analysis revealed that STIP1 was an independent prognostic factor for overall survival and disease-free survival in patients with CRC. In conclusion, our results suggest that STIP1 acts as an oncogene in CRC and can therefore serve as a biomarker for the prognosis of patients with CRC.

Wnt/beta-catenin signaling is frequently activated in hepatocellular carcinoma (HCC). Better understanding the mechanism for its over-activation would help the therapy. In this study, we have shown that the stress-induced phosphoprotein 1 (STIP1) is up-regulated in the HCC tissues. Functional studies showed that STIP1 promoted the growth, colony formation and migration of cancer cells. However, knocking down the expression of STIP1 inhibited the growth, colony formation and migration of cancer cells. Molecular mechanism study showed that STIP1 interacted with Axin, enhanced the interaction between Axin and DVL2, thus activated beta-catenin/TCF signaling. Taken together, our study demonstrated the oncogenic roles of STIP1 in the progression of HCC, and suggested that STIP1 might be a therapeutic target.

Recent studies indicated that insufficient radiofrequency ablation (RFA) could endow hepatocellular carcinoma (HCC) with higher aggressive potential. Stress-induced phosphoprotein 1 (STIP1), which was found highly expressed in HCC, is a chaperone molecule mediating cell homeostasis under thermal stress. We aimed to explore the role of STIP1 on the metastasis of residual HCC after RFA. Mice model with orthotopic HCC implants or caudal vein injection were employed to assess potential of lung metastasis and/or intrahepatic metastasis (IHM) of HCC cells. Cell culture model was used to determine cell invasion, mesenchymal marker genes expression, and underlying molecular mechanisms. Clinical specimens were collected to analyze the relationship between STIP1 and clinical outcome. We found that insufficient RFA elicited more IHM of HCCLM3 tumors, which could be reduced by silencing STIP1. Knockdown of STIP1 also significantly decreased lung metastatic potential of HCCLM3 cells. In vitro, HCCLM3 and HepG2 displayed a spindle-shaped morphology with upregulation of STIP1 and mesenchymal markers after sublethal heat exposure. Mechanistically, heat exposure induced the formation of STIP1-heat shock protein 90 (HSP90) complex, which could shuttle epithelial transcription repressor Snail1 into nucleus and regulate mesenchymal gene transcription. Blocking the HSP90-STIP1 complex reduced the invasive potential of HCC cells after heat exposure. Using clinical specimen, we found that STIP1 was expressed significantly higher in metastatic tumor tissues and in sera from metastatic HCC patients (p < 0.05). The high expression of STIP1 was significantly linked to shorter recurrence-free survival (p < 0.05). To sum up, our study found that STIP1 is positively associated with the sublethal heat-induced cancer cell metastasis through mediating the mesenchymal gene transcription. Blocking STIP1 activity may suppress HCC cell metastatic potential after RFA.

Osteosarcoma is an aggressive bone tumor with high metastasis rate in the lungs and affects both humans and dogs in a similar way. Three-dimensional tumor cell cultures mimic the in vivo situation of micro-tumors and metastases and are therefore better experimental in vitro models than the often applied two-dimensional monolayer cultures. The aim of the present study was to perform comparative proteomics of standard monolayer cultures of canine osteosarcoma cells (D17) and three-dimensional spheroid cultures, to better characterize the 3D model before starting with experiments like migration assays. Using DIGE in combination with MALDI-TOF/TOF we found 27 unique canine proteins differently represented between these two culture systems, most of them being part of a functional network including mainly chaperones, structural proteins, stress-related proteins, proteins of the glycolysis/gluconeogenesis pathway and oxidoreductases. In monolayer cells, a noticeable shift to more acidic pI values was noticed for several proteins of medium to high abundance; two proteins (protein disulfide isomerase A3, stress-induced-phosphoprotein 1) showed an increase of phosphorylated protein species. Protein distribution within the cells, as detected by immunohistochemistry, displayed a switch of stress-induced-phosphoprotein 1 from the cytoplasm (in monolayer cultures) to the nucleus (in spheroid cultures). Additionally, Western blot testing revealed upregulated concentrations of metastasin (S100A4), triosephosphate isomerase 1 and septin 2 in spheroid cultures, in contrast to decreased concentrations of CCT2, a subunit of the T-complex. Results indicate regulation of stress proteins in the process of three-dimensional organization characterized by a hypoxic and nutrient-deficient environment comparable to tumor micro-metastases.
SIGNIFICANCE: Osteosarcoma is an aggressive bone tumor that early spreads to the lungs. Three-dimensional tumor cell cultures represent the avascular stage of micro-tumors and metastases, and should therefore represent a better experimental in vitro model compared to two-dimensional monolayer cultures. Significant differences have been reported in response to drug and radiation treatment between these two culture systems. A gel-based proteomic investigation was performed to compare protein patterns of a canine osteosarcoma cell line cultivated under those two conditions, to learn more about altered cell composition and its impact on cell behaviour. Due to the fact that the canine osteosarcoma is an accepted model for the human disease, results will be relevant for the human species as well.

BACKGROUND: Stress-Inducible Protein-1 (STIP1) is a co-chaperone that associates directly with heat shock proteins, and regulates motility of various types of cancer. In the present study, we investigated the role of STIP1 on metastasis of gastric cancer (GC).
METHODS: In vivo metastatic experimental model was employed to investigate the effect of STIP1 on metastasis of GC cells. Loss-of-function and gain-of-function experiments were performed to examine the role of STIP1 on metastasis of GC cells. Western blot, immunofluorescence staining, migration and invasion assays, microarray and KEGG pathway analysis were applied to explore the underlying mechanism.
RESULTS: In current study, we demonstrated that STIP1 promoted lung metastasis of GC cells in vivo. Furthermore, STIP1 significantly enhanced migration and invasion abilities of GC cells. In contrast, knock-down of STIP1 yielded the opposite effects on these phenotypes in vitro. STIP1 promoted tumor metastasis through inducing epithelial-to-mesenchymal transition in GC cells. Mechanistically, STIP1 promoted GC metastasis via up-regulation of targeted genes in Wnt/β-catenin signaling pathway, including c-Myc and Cyclin D1, and accompanied with nuclear translocation of β-catenin.
CONCLUSIONS: Our findings indicate that elevated expression of STIP1 exhibited a metastasis-promoting effect in GC cells through activation of Wnt/β-catenin signaling pathway. STIP1 may be served as a potential therapeutic target for preventing GC metastasis.

Stress-induced phosphoprotein 1 (STIP1) is an adaptor protein that bridges between HSP70 and HSP90 folding and a secretory protein which regulates malignant cell growth. However, the role of STIP1 in hepatocellular carcinoma (HCC) remains unknown. Here, we found high expression of STIP1 in tumors was associated with worse overall survival (41.3 vs 62.7 months, P < 0.001) in 231 HCC patients. STIP1 was overexpressed in HCC tissues compared to adjacent non-tumor liver tissue (64.9% vs 4.0% P < 0.001), and serum STIP1 levels of HCC patients were elevated compared to healthy controls (P < 0.001). Mechanistically, STIP1 promoted HCC growth through PI3K-AKT-dependent anti-apoptotic pathway. STIP1 mediated cell growth in an autocrine fashion, which could be suppressed either by neutralizing extracellular STIP1 or by knocking down intracellular STIP1. In xenograft mouse model, knockdown of STIP1 significantly reduced tumor growth (P < 0.001). In conclusion, STIP1 is upregulated in HCC and associated with poor clinical prognosis. Blocking STIP1 activity suppresses HCC cell growth, providing the rationale for STIP1 as a potential therapeutic target in HCC.

Esophageal squamous cell carcinoma (ESCC) remains one of the leading causes of cancer-related mortality around the world. The identification of novel serum biomarkers is required for early detection of ESCC. This study was designed to elucidate whether autoantibodies against STIP1 could be a diagnostic biomarker in ESCC. An enzyme-linked immunosorbent assay was performed to detect serum levels of STIP1 autoantibodies in a training cohort (148 ESCC patients and 111 controls) and a validation cohort (60 ESCC patients and 40 controls). Mann-Whitney's

BACKGROUND: Glioblastoma (GBM), a highly aggressive brain tumor, contains a subpopulation of glioblastoma stem-like cells (GSCs) that play roles in tumor maintenance, invasion, and therapeutic resistance. GSCs are therefore a promising target for GBM treatment. Our group identified the cellular prion protein (PrP
METHODS: GSCs expressing different levels of PrP
RESULTS: We observed that, when GBM cells are cultured as neurospheres, they express specific stemness markers such as CD133, CD15, Oct4, and SOX2; PrP
CONCLUSIONS: In conclusion, our results show that the modulation of HOP-PrP

Bone metastases are responsible for some of the most devastating complications of renal cell carcinoma (RCC). However, pro-metastatic factors leading to the highly osteolytic characteristics of RCC bone metastasis have barely been explored. We previously developed novel bone-seeking RCC cell lines by the in vivo selection strategy and performed a comparative proteome analysis on their total cell lysate. Here, we focused on STIP1 (stress-induced phosphoprotein 1), the high up-regulated protein in the bone-seeking cells, and explored its clinical relevance and functions in RCC bone metastasis. We observed high levels of both intracellular and extracellular STIP1 protein in bone metastatic tissue samples. Elevated STIP1 mRNA in the primary RCC tumors remarkably correlated with worse clinical outcomes. Furthermore, both human recombinant STIP1 protein and anti-STIP1 neutralizing antibody were used in the functional studies. We found that 1) STIP1 protein on the extracellular surface of tumor cells promoted the proliferation and migration/invasion of RCC tumor cells through the autocrine STIP1-ALK2-SMAD1/5 pathway; and 2) STIP1 protein secreted into the extracellular tumor stromal area, promoted the differentiation of osteoclasts through the paracrine STIP1-PrPc-ERK1/2 pathway. Increased cathepsin K (CTSK), the key enzyme secreted by osteoclasts to degrade collagen and other matrix proteins during bone resorption was further detected in the differentiated osteoclasts. These results provide evidence of the great potential of STIP1 as a novel biomarker and therapeutic target in RCC bone metastasis.

Juxtaposition of two different genes or gene parts due to chromosomal rearrangement is a well-known neoplasia-associated pathogenetic mechanism. The detection and characterization of such tumorigenic fusions is of great importance both research-wise, diagnostically because they may be specific for distinct tumor entities, and because they may serve as therapeutic targets for antioncogenic drugs that interact directly with the molecular changes responsible for neoplastic transformation.At present, more than 10,000 fusion transcripts have been reported in different types of neoplasia, with one tenth of them being identified in squamous cell carcinomas (SCC) of different locations. No recurrent fusion gene has to date been identified in SCC of the vulva.We performed high-throughput paired-end RNA-sequencing of 12 vulvar SCC and found two recurrent fusions with the STIP1-CREB3L1 and ZDHHC5-GPR137 being present in two tumors each. The transcripts were detected only in the tumor samples, not in normal vulvar tissue from healthy donors used as control. The CREB3L1 and ZDHHC5 genes encode proteins involved in transcription suggesting that the chimeras may alter downstream events in their respective pathways. Expression analysis of the CREB3L1 gene showed the presence of two distinct groups of tumors, one having fusion and downregulation of the gene and the other showing upregulation of CREB3L1.

Better and sensitive biomarkers are needed to help understand the mechanism of disease onset, progression, prognosis and monitoring of the therapeutic response. Aim of this study was to identify the candidate circulating markers of chronic-phase chronic myeloid leukemia (CP-CML) manifestations, having potential to develop into predictive- or monitoring-biomarkers. A proteomic approach, two-dimensional gel electrophoresis in conjunction with mass spectrometry (2DE-MS), was employed for this purpose. Based on the spot intensity measurements, six proteins were found to be consistently dysregulated in CP-CML subjects compared to the healthy controls [false discovery rate (FDR) threshold ≤0.05]. These were identified as α-1-antichymotrypsin, α-1-antitrypsin, CD5 molecule-like, stress-induced phosphoprotein 1, vitamin D binding protein isoform 1 and transthyretin by MS analysis [PMF score ≥79; data accessible via ProteomeXchange with identifier PXD002757]. Quantitative ELISA, used for validation of candidate proteins both in the pre-treated and nilotinib-treated CP-CML cases, demonstrate that CD5 molecule-like, transthyretin and alpha-1-antitrypsin may serve as useful predictive markers and aid in monitoring the response of TKI-based therapy (ANOVA p < 0.0001). Two of the circulating marker proteins, identified in this study, had not previously been associated with chronic- or acute-phase myeloid leukemia. Exploration of their probable association with CP-CML, in a larger study cohort, may add to our understanding of the disease mechanism besides developing clinically useful biomarkers in future.

The Hsp70/Hsp90 organising protein (HOP) is a co-chaperone essential for client protein transfer from Hsp70 to Hsp90 within the Hsp90 chaperone machine. Although HOP is upregulated in various cancers, there is limited information from in vitro studies on how HOP expression is regulated in cancer. The main objective of this study was to identify the HOP promoter and investigate its activity in cancerous cells. Bioinformatic analysis of the -2500 to +16 bp region of the HOP gene identified a large CpG island and a range of putative cis-elements. Many of the cis-elements were potentially bound by transcription factors which are activated by oncogenic pathways. Luciferase reporter assays demonstrated that the upstream region of the HOP gene contains an active promoter in vitro. Truncation of this region suggested that the core HOP promoter region was -855 to +16 bp. HOP promoter activity was highest in Hs578T, HEK293T and SV40- transformed MEF1 cell lines which expressed mutant or inactive p53. In a mutant p53 background, expression of wild-type p53 led to a reduction in promoter activity, while inhibition of wild-type p53 in HeLa cells increased HOP promoter activity. Additionally, in Hs578T and HEK293T cell lines containing inactive p53, expression of HRAS increased HOP promoter activity. However, HRAS activation of the HOP promoter was inhibited by p53 overexpression. These findings suggest for the first time that HOP expression in cancer may be regulated by both RAS activation and p53 inhibition. Taken together, these data suggest that HOP may be part of the cancer gene signature induced by a combination of mutant p53 and mutated RAS that is associated with cellular transformation.

Even though bystander effects pertaining to radiation risk assessment has been extensively studied, the molecular players of radiation induced bystander effect (RIBE) in the context of cancer radiotherapy are poorly known. In this regard, the present study is aimed to investigate the effect of irradiated tumor cells on the bystander counterparts in mouse fibrosarcoma (WEHI 164 cells) tumor model. Mice co-implanted with WEHI 164 cells γ-irradiated with a lethal dose of 15 Gy and unirradiated (bystander) WEHI 164 cells showed inhibited tumor growth, which was measured in terms of tumor volume and Luc+WEHI 164 cells based bioluminescence in vivo imaging. Histopathological analysis and other assays revealed decreased mitotic index, increased apoptosis and senescence in these tumor tissues. In addition, poor angiogenesis was observed in these tumor tissues, which was further confirmed by fluorescence imaging of tumor vascularisation and CD31 expression by immuno-histochemistry. Interestingly, the growth inhibitory bystander effect was exerted more prominently by soluble factors obtained from the irradiated tumor cells than the cellular fraction. Cytokine profiling of the supernatants obtained from the irradiated tumor cells showed increased levels of VEGF, Rantes, PDGF, GMCSF and IL-2 and decreased levels of IL-6 and SCF. Comparative proteomic analysis of the supernatants from the irradiated tumor cells showed differential expression of total 24 protein spots (21 up- and 3 down-regulated) when compared with the supernatant from the unirradiated control cells. The proteins which showed substantially higher level in the supernatant from the irradiated cells included diphosphate kinase B, heat shock cognate, annexin A1, angiopoietin-2, actin (cytoplasmic 1/2) and stress induced phosphoprotein 1. However, the levels of proteins like annexin A2, protein S100 A4 and cofilin was found to be lower in this supernatant. In conclusion, our results provided deeper insight about the damaging RIBE in an in vivo tumor model, which may have significant implication in improvement of cancer radiotherapy.

Overexpression of stress-induced phosphoprotein 1 (STIP1) - a co-chaperone of heat shock protein (HSP) 70/HSP90 - and activation of the JAK2-STAT3 pathway occur in several tumors. Combined treatment with a HSP90 inhibitor and a JAK2 inhibitor exert synergistic anti-cancer effects. Here, we show that STIP1 stabilizes JAK2 protein in ovarian and endometrial cancer cells. Knock-down of endogenous STIP1 decreased JAK2 and phospho-STAT3 protein levels. The N-terminal fragment of STIP1 interacts with the N-terminus of JAK2, whereas the C-terminal DP2 domain of STIP1 mediates the interaction with HSP90 and STAT3. A peptide fragment in the DP2 domain of STIP1 (peptide 520) disrupted the interaction between STIP1 and HSP90 and induced cell death through JAK2 suppression. In an animal model, treatment with peptide 520 inhibited tumor growth. In summary, STIP1 modulates the function of the HSP90-JAK2-STAT3 complex. Peptide 520 may have therapeutic potential in the treatment of JAK2-overexpressing tumors.

AIMS: The distinction between intrahepatic cholangiocarcinoma (ICC) and benign bile duct lesions can be challenging. Using our previously identified potential biomarkers for ICC, we examined whether these are useful for the differential diagnosis of ICC, bile duct adenoma and reactive bile duct proliferations in an immunohistochemical approach and identified a diagnostic marker panel including known biomarkers.
METHODS: Subjects included samples from 77 patients with ICC, 33 patients with bile duct adenoma and 47 patients with ductular reactions in liver cirrhosis. Our previously identified biomarkers (stress-induced phosphoprotein 1 (STIP1), SerpinH1, 14-3-3Sigma) were tested immunohistochemically following comparison with candidates from the literature (cluster of differentiation 56, heat shock protein (HSP)27, HSP70, B-cell-lymphoma2, p53, ki67).
RESULTS: The expression of SerpinH1 and 14-3-3Sigma was significantly higher in ICC than in bile duct adenomas and ductular reactions (p<0.05), whereas STIP1 expression was significantly higher (p<0.05) in ICC than in ductular reactions, but the difference to the bile duct adenoma group was not significant. A panel of the biomarker SerpinH1, 14-3-3Sigma and ki67 (≥2 marker positive) showed a high diagnostic accuracy (sensitivity 87.8%, specificity 95.9%, accuracy 91.8%) in the differential diagnosis of ICC versus non-malignant bile duct lesions.
CONCLUSIONS: This suggests that 14-3-3Sigma and SerpinH1 may be useful in the differential diagnosis of malignant, benign and reactive bile duct lesions in addition to ki67 where a cut-off of >5% might be used for the distinction of malignant and non-malignant lesions.

The Hsp70/Hsp90 organising protein (Hop), also known as stress-inducible protein 1 (STI1), has received considerable attention for diverse cellular functions in both healthy and diseased states. There is extensive evidence that intracellular Hop is a co-chaperone of the major chaperones Hsp70 and Hsp90, playing an important role in the productive folding of Hsp90 client proteins. Consequently, Hop is implicated in a number of key signalling pathways, including aberrant pathways leading to cancer. However, Hop is also secreted and it is now well established that Hop also serves as a receptor for the prion protein, PrP(C). The intracellular and extracellular forms of Hop most likely represent two different isoforms, although the molecular determinants of these divergent functions are yet to be identified. There is also a growing body of research that reports the involvement of Hop in cellular activities that appear independent of either chaperones or PrP(C). While Hop has been shown to have various cellular functions, its biological function remains elusive. However, recent knockout studies in mammals suggest that Hop has an important role in embryonic development. This review provides a critical overview of the latest molecular, cellular and biological research on Hop, critically evaluating its function in healthy systems and how this function is adapted in diseases states.

The aim of this study was the identification of novel biomarker candidates for the diagnosis of cholangiocellular carcinoma (CCC) and its immunohistochemical differentiation from benign liver and bile duct cells. CCC is a primary cancer that arises from the epithelial cells of bile ducts and is characterized by high mortality rates due to its late clinical presentation and limited treatment options. Tumorous tissue and adjacent non-tumorous liver tissue from eight CCC patients were analyzed by means of two-dimensional differential in-gel electrophoresis and mass-spectrometry-based label-free proteomics. After data analysis and statistical evaluation of the proteins found to be differentially regulated between the two experimental groups (fold change ≥ 1.5; p value ≤ 0.05), 14 candidate proteins were chosen for determination of the cell-type-specific expression profile via immunohistochemistry in a cohort of 14 patients. This confirmed the significant up-regulation of serpin H1, 14-3-3 protein sigma, and stress-induced phosphoprotein 1 in tumorous cholangiocytes relative to normal hepatocytes and non-tumorous cholangiocytes, whereas some proteins were detectable specifically in hepatocytes. Because stress-induced phosphoprotein 1 exhibited both sensitivity and specificity of 100%, an immunohistochemical verification examining tissue sections of 60 CCC patients was performed. This resulted in a specificity of 98% and a sensitivity of 64%. We therefore conclude that this protein should be considered as a potential diagnostic biomarker for CCC in an immunohistochemical application, possibly in combination with other candidates from this study in the form of a biomarker panel. This could improve the differential diagnosis of CCC and benign bile duct diseases, as well as metastatic malignancies in the liver.

In this paper, we describe the elucidation of the target of an aptamer against ovarian cancer previously obtained by cell-SELEX (SELEX = systematic evolution of ligands by exponential enrichment). The target's identity, stress-induced phosphoprotein 1 (STIP1), was determined by mass spectrometry and validated by flow cytometry, using siRNA silencing and protein blotting. Initial oncologic studies show that the aptamer inhibits cell invasion, indicating that STIP1, which is currently under investigation as a potential biomarker for ovarian cancer, plays a critical role in this process. These results serve as an excellent example of how protein target identification of aptamers obtained by cell-SELEX can serve as a means to identify promising biomarker candidates and can promote the development of aptamers as a new drug class to block important oncological processes.

Here, we show for the first time that the familial breast/ovarian cancer susceptibility gene, BRCA1, along with interacting ΔNp63 proteins, transcriptionally upregulate the putative tumour suppressor protein, S100A2. Both BRCA1 and ΔNp63 proteins are required for S100A2 expression. BRCA1 requires ΔNp63 proteins for recruitment to the S100A2 proximal promoter region, while exogenous expression of individual ΔNp63 proteins cannot activate S100A2 transcription in the absence of a functional BRCA1. Consequently, mutation of the ΔNp63/p53 response element within the S100A2 promoter completely abrogates the ability of BRCA1 to upregulate S100A2. S100A2 shows growth control features in a range of cell models. Transient or stable exogenous S100A2 expression inhibits the growth of BRCA1 mutant and basal-like breast cancer cell lines, while short interfering RNA (siRNA) knockdown of S100A2 in non-tumorigenic cells results in enhanced proliferation. S100A2 modulates binding of mutant p53 to HSP90, which is required for efficient folding of mutant p53 proteins, by competing for binding to HSP70/HSP90 organising protein (HOP). HOP is a cochaperone that is required for the efficient transfer of proteins from HSP70 to HSP90. Loss of S100A2 leads to an HSP90-dependent stabilisation of mutant p53 with a concomitant loss of p63. Accordingly, S100A2-deficient cells are more sensitive to the HSP-90 inhibitor, 17-N-allylamino-17-demethoxygeldanamycin, potentially representing a novel therapeutic strategy for S100A2- and BRCA1-deficient cancers. Taken together, these data demonstrate the importance of S100A2 downstream of the BRCA1/ΔNp63 signalling axis in modulating transcriptional responses and enforcing growth control mechanisms through destabilisation of mutant p53.

Stress-induced phosphoprotein1 (STIP1) is a candidate biomarker in epithelial ovarian cancer (EOC). In this study, we investigated in detail the expression of STIP1, as well as its functions, in EOC. STIP1 expression was assessed by immunohistochemistry (IHC) and the results were compared with clinicopathologic factors, including survival data. The effects of STIP1 gene silencing via small interfering RNA (siRNA) were examined in EOC cells and a xenograft model. The expression of STIP1 protein in EOC was significantly higher than in the other study groups (P < 0.001), and this increase of expression was significantly associated with tumor stage (P = 0.005), tumor grade (P = 0.029), and lymph node metastasis (P = 0.020). In multivariate analysis, overall survival in EOC was significantly shorter in cases with high STIP1 expression (HR = 2.78 [1.01-7.63], P = 0.047). STIP1 silencing in EOC cells resulted in inhibition of cell proliferation and invasion. In addition, in vivo experiments using STIP1 siRNA clearly showed a strong inhibition of tumor growth and a modulation of expression of prosurvival and apoptotic genes, further suggesting that STIP1 silencing can prevent cell proliferation and invasion. In conclusion, increased STIP1 expression is associated with poor survival outcome in EOC, and STIP1 may represent a useful therapeutic target in EOC patients.

We cocultured calycosin with human hepatocellular carcinoma cell line (BEL-7402) to investigate the effect on cell proliferation. Calycosin can markedly block the cell growth in G1 phase (P < 0.01) on the IC50 concentration. There were seventeen genes involved in cell-cycle regulation showing differentially expressed in treated cells detected by gene chip. Eight genes were upregulated and nine genes were downregulated. Downregulated TFDP-1, CDKN2D, and SPK2 and upregulated CDC2 and CCNB1 might affect cell cycle of tumor cells. Furthermore, we checked the transcription pattern using 2D gel method to find different expression of proteins in human hepatocellular carcinoma cells after exposure to calycosin. Fourteen proteins were identified by matrix-assisted laser desorption/ionization-time of flight-mass spectrometry (MALDI-TOF-MS). Twelve proteins expression were increased such as transgelin 2, pyridoxine 5'-phosphate, stress-induced-phosphoprotein 1, peroxiredoxin 1, endoplasmic reticulum protein 29, and phosphoglycerate mutase 1. Only thioredoxin peroxidase and high-mobility group box1 proteins' expression decreased. Both genes and proteins changes might be relate to the mechanism of antitumor effect under treatment of calycosin. In conclusion, calycosin has a potential effect to inhibit the BEL-7402 cell growth by inhibiting some oncogene expression and increasing anticancer genes expression, what is more, by blocking cell cycle.

The aim of this study was to detect stress-induced phosphoprotein 1 (STIP1) expression in papillary thyroid carcinoma (PTC) and to analyze its association with prognosis of PTC patients. Immunohistochemistry was performed to detect the expression of STIP1 in 113 PTC tissues and paired adjacent noncancerous tissues. The χ2 test was used to analyze the relationship between STIP1 expression and clinicopathological characteristics. Survival curves were plotted by the Kaplan-Meier method and compared using the log-rank test. Survival data was evaluated using univariate and multivariate Cox regression analysis. We identified abnormally elevated expression of STIP1 protein in PTC tissues compared to paired adjacent noncancerous tissues. Clinicopathological analysis showed that STIP1 expression was significantly correlated with tumor size (P = 0.017), lymph node metastasis (P = 0.007), and TNM stage (P = 0.026). Patients with higher STIP1 expression had shorter overall survival time, whereas those with lower STIP1 expression had longer survival time. Multivariate analysis suggested that STIP1 expression might be an independent prognostic indicator (P < 0.05) for the survival of patients with PTC. In conclusion, our findings provide evidences that positive expression of STIP1 in PTC may be important in the acquisition of an aggressive phenotype, and it is an independent biomarker for poor prognosis of patients with PTC.

OBJECTIVE: Stress-induced phosphoprotein 1 (STIP1) was recently identified as a potential tumor marker for human ovarian cancer. This study further evaluates the usefulness of STIP1 in ovarian tumor patients with normal CA125 serum levels.
MATERIALS AND METHODS: STIP1 and CA125 were immunohistochemically analyzed in 84 primary ovarian cancer and 30 benign ovarian tumors in patients with serum CA125 levels < 35 U/mL before surgery. Histoscores (0-300) were calculated as staining intensities (0-3) multiplied by percentage of tumor tissue (0-100%).
RESULTS: The cell types of the 84 cancers included 11 serous, 10 clear-cell, 51 mucinous, and 12 endometrioid carcinomas. There were 55 patients with invasive cancer and 29 with borderline ovarian tumors. The histoscores of STIP1, but not of CA125, in invasive cancer (mean ± SD, 186.3 ± 82.5) were significantly (p < 0.0001) higher than those seen in borderline ovarian tumors (86.2 ± 85.5). When the STIP1 histoscore was set at 183.8, invasive cancers (n = 55) were identified from benign tumors (n = 30) with a sensitivity of 56.4%, a specificity of 93.3%, a positive predictive value of 93.9%, and a negative predictive value of 53.8%. Results of receiver operating characteristics analysis showed that the area under curve of the STIP1 histoscore was 0.755, which was superior to that of CA125 (0.599).
CONCLUSION: STIP1 histoscores may be useful in detecting invasive human ovarian cancer in patients with low serum CA125 levels.

Hepatocellular carcinoma (HCC) is the fifth most common cancer worldwide and the third highest cause of cancer-related mortality in humans. Epigallocatechin-3-gallate (EGCG) has been shown to inhibit the metastatic activity of certain cancer cells. The aim of this study was to determine the effects and molecular mechanism(s) of action of EGCG in human HCC cells. A migration and invasion assay for the metastatic behavior of HCCLM6 cells was performed. The anti-metastatic effects of EGCG were investigated by RT-PCR and gelatin zymography. A total cellular protein profile was obtained using 2-dimensional gel electrophoresis (2-DE), followed by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS) analyses of proteins with significant differences in expression following treatment with EGCG. The results revealed that EGCG induced apoptosis and inhibited the metastasis of HCCLM6 cells. The anti-metastatic effects of EGCG were associated with the inhibition of matrix metalloproteinase (MMP)-2 and MMP-9 activity. The expression levels of far upstream element (FUSE) binding protein 1 (FUBP1), heat shock protein beta 1 (HSPB1), heat shock 60 kDa protein 1 (chaperonin) (CH60) and nucleophosmin (NPM) proteins, which are associated with metastasis, were significantly altered in the EGCG-treated HCCLM6 cells. The data from the present study suggest that EGCG has potential as a therapeutic agent for the treatment of HCC.

The use of chemopreventive natural compounds represents a promising strategy in the search for novel therapeutic agents in cancer. Resveratrol (3,4',5-trans-trihydroxystilbilene) is a dietary polyphenol found in fruits, vegetables and medicinal plants that exhibits chemopreventive and antitumor effects. In this study, we searched for modulated proteins with preventive or therapeutic potential in MCF-7 breast cancer cells exposed to resveratrol. Using two-dimensional electrophoresis we found significant changes (FC >2.0; p≤0.05) in the expression of 16 proteins in resveratrol-treated MCF-7 cells. Six down-regulated proteins were identified by tandem mass spectrometry (ESI-MS/MS) as heat shock protein 27 (HSP27), translationally-controlled tumor protein, peroxiredoxin-6, stress-induced-phosphoprotein-1, pyridoxine-5'-phosphate oxidase-1 and hypoxanthine-guanine phosphoribosyl transferase; whereas one up-regulated protein was identified as triosephosphate isomerase. Particularly, HSP27 overexpression has been associated to apoptosis inhibition and resistance of human cancer cells to therapy. Consistently, we demonstrated that resveratrol induces apoptosis in MCF-7 cells. Apoptosis was associated with a significant increase in mitochondrial permeability transition, cytochrome c release in cytoplasm, and caspases -3 and -9 independent cell death. Then, we evaluated the chemosensitization effect of increasing concentrations of resveratrol in combination with doxorubicin anti-neoplastic agent in vitro. We found that resveratrol effectively sensitize MCF-7 cells to cytotoxic therapy. Next, we evaluated the relevance of HSP27 targeted inhibition in therapy effectiveness. Results evidenced that HSP27 inhibition using RNA interference enhances the cytotoxicity of doxorubicin. In conclusion, our data indicate that resveratrol may improve the therapeutic effects of doxorubicin in part by cell death induction. We propose that potential modulation of HSP27 levels using natural alternative agents, as resveratrol, may be an effective adjuvant in breast cancer therapy.

Stress-induced phosphoprotein 1 (STIP1) has been recently identified as a released biomarker in human ovarian cancer. In addition, STIP1 secreted by human ovarian cancer cells has been shown to promote tumor cell proliferation by binding to ALK2 (activin A receptor, type II-like kinase 2) and activating the SMAD-ID3 signaling pathways. In this study, a total of 330 ovarian cancer tumor samples were evaluated for STIP1 expression by immunohistochemistry and analyzed for a possible correlation with patient characteristics and survival. The quantification of immunoreactivity was accomplished by applying an immunohistochemical scoring system (histoscore). Patients with high-level STIP1 expression (histoscore ≥169) had a significantly worse survival (high STIP1, mean survival time = 76 months; low STIP1, mean survival time = 112 months; P<0.0001). Moreover, STIP1 histoscores were significantly higher in high-grade tumors (grade 3) than in low-grade (grade 1-2) malignancies (P<0.0001), suggesting that STIP1 may be a proxy for tumor aggressiveness. The results of multivariable analysis revealed that high STIP1 histoscores, advanced stages, histologic types, and the presence of residual disease (≥2 cm) were independent predictors of poor prognosis. The addition of STIP1 histoscores improved the prediction of overall and progression-free survival rates in the multivariable Cox proportional hazard model. The treatment of ovarian cancer cells with recombinant STIP1 stimulated cell proliferation and migration, but co-treatment with anti-STIP1 antibodies abrogated this effect. Our findings suggest that STIP1 expression may be related to prognosis and that the STIP1 pathway may represent a novel therapeutic target for human ovarian cancer.

Stress-induced phosphoprotein 1 (STIP1), a cochaperone that organizes other chaperones, heat shock proteins (HSPs), was recently shown to be secreted by human ovarian cancer cells. In neuronal tissues, binding to prion protein was required for STIP1 to activate the ERK (extracellular-regulated MAP kinase) signaling pathways. However, we report that STIP1 binding to a bone morphogenetic protein (BMP) receptor, ALK2 (activin A receptor, type II-like kinase 2), was necessary and sufficient to stimulate proliferation of ovarian cancer cells. The binding of STIP1 to ALK2 activated the SMAD signaling pathway, leading to transcriptional activation of ID3 (inhibitor of DNA binding 3), promoting cell proliferation. In conclusion, ovarian-cancer-tissue-secreted STIP1 stimulates cancer cell proliferation by binding to ALK2 and activating the SMAD-ID3 signaling pathways. Although animal studies are needed to confirm these mechanisms in vivo, our results may pave the way for developing novel therapeutic strategies for ovarian cancer.

Heat shock proteins Hsp90 and Hsp70 facilitate protein folding but can also direct proteins for ubiquitin-mediated degradation. The mechanisms regulating these opposite activities involve Hsp binding to co-chaperones including CHIP and HOP at their C-termini. We demonstrated that the extreme C-termini of Hsp70 and Hsp90 contain phosphorylation sites targeted by kinases including CK1, CK2 and GSK3-β in vitro. The phosphorylation of Hsp90 and Hsp70 prevents binding to CHIP and thus enhances binding to HOP. Highly proliferative cells contain phosphorylated chaperones in complex with HOP and phospho-mimetic and non-phosphorylable Hsp mutant proteins show that phosphorylation is directly associated with increased proliferation rate. We also demonstrate that primary human cancers contain high levels of phosphorylated chaperones and show increased levels of HOP protein and mRNA. These data identify C-terminal phosphorylation of Hsp70 and Hsp90 as a switch for regulating co-chaperone binding and indicate that cancer cells possess an elevated protein folding environment by the concerted action of co-chaperone expression and chaperone modifications. In addition to identifying the pathway responsible for regulating chaperone-mediated protein folding/degradation balances in normal cells, the data provide novel mechanisms to account for the aberrant chaperone activities observed in human cancer cells and have implications for the application of anti-chaperone therapies in cancer treatment.

Although the highest incidence of esophageal squamous cell carcinoma (ESCC) has repeatedly been reported from Persia (Iran), nevertheless the so far proteomic published reports were limited to one study on tissue specimens. Here we report the proteome of a newly established cell line from Persian ESCC patients and compare it with the normal primary cell proteome. Among polypeptides, whose expression was different in cell line sixteen polypeptides were identified by MALDI/TOF/TOF spectrometry. S100-A8 protein, annexin A1, annexin A2, regulatory subunit of calpain, subunit alpha type-3 of proteasome and glutamate dehydrogenase 1 were proteins down-regulated in cell line while peroxiredoxin-5, non-muscle myosin light polypeptide 6, keratin 1, annexin A4, keratin 8, tropomyosin 3, stress-induced-phosphoprotein 1 and albumin were found to be subject of up-regulation in cell line compared to the primary normal cells. The proteomic results were further verified by western blotting and RT-PCR on annexin A1 and keratin 8. In addition, among the aforementioned proteins, glutamate dehydrogenase 1, regulatory subunit of calpain, subunit alpha of type-3 proteasome and annexin A4 are proteins whose deregulation in ESCC is reported for the first time by this study.