Gene Summary

Gene:PIK3R1; phosphoinositide-3-kinase regulatory subunit 1
Aliases: p85, AGM7, GRB1, IMD36, p85-ALPHA
Summary:Phosphatidylinositol 3-kinase phosphorylates the inositol ring of phosphatidylinositol at the 3-prime position. The enzyme comprises a 110 kD catalytic subunit and a regulatory subunit of either 85, 55, or 50 kD. This gene encodes the 85 kD regulatory subunit. Phosphatidylinositol 3-kinase plays an important role in the metabolic actions of insulin, and a mutation in this gene has been associated with insulin resistance. Alternative splicing of this gene results in four transcript variants encoding different isoforms. [provided by RefSeq, Jun 2011]
Databases:OMIM, HGNC, Ensembl, GeneCard, Gene
Protein:phosphatidylinositol 3-kinase regulatory subunit alpha
Source:NCBIAccessed: 01 September, 2019


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 (1994-2019)
Graph generated 01 September 2019 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.

  • RT-PCR
  • Chromosome 5
  • raf Kinases
  • MicroRNAs
  • Phosphatidylinositol 3-Kinases
  • Cell Proliferation
  • Tissue Array Analysis
  • Brain Tumours
  • Mutation
  • Single Nucleotide Polymorphism
  • Brain Tumours
  • Endometrial Cancer
  • DNA Mutational Analysis
  • Risk Factors
  • Cancer Gene Expression Regulation
  • Cell Movement
  • Whole Exome Sequencing
  • Class I Phosphatidylinositol 3-Kinases
  • Genetic Predisposition
  • Promoter Regions
  • ras Proteins
  • Breast Cancer
  • Staging
  • Immunohistochemistry
  • Myeloid-Derived Suppressor Cells
  • Single-Stranded Conformational Polymorphism
  • Up-Regulation
  • Apoptosis
  • Squamous Cell Carcinoma of Head and Neck
  • PTEN
  • Down-Regulation
  • Gene Expression Profiling
  • Stomach Cancer
  • Messenger RNA
  • Glioblastoma
  • Neoplasm Proteins
  • Biomarkers, Tumor
  • Proto-Oncogene Proteins p21(ras)
  • Oligonucleotide Array Sequence Analysis
  • Bladder Cancer
  • Gene Regulatory Networks
  • High-Throughput Nucleotide Sequencing
Tag cloud generated 01 September, 2019 using data from PubMed, MeSH and CancerIndex

Specific Cancers (6)

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: PIK3R1 (cancer-related)

Jin H, Jang Y, Cheng N, et al.
Restoration of mutant K-Ras repressed miR-199b inhibits K-Ras mutant non-small cell lung cancer progression.
J Exp Clin Cancer Res. 2019; 38(1):165 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: miRNAs play crucial role in the progression of K-Ras-mutated nonsmall cell lung cancer (NSCLC). However, most studies have focused on miRNAs that target K-Ras. Here, we investigated miRNAs regulated by mutant K-Ras and their functions.
METHODS: miRNAs regulated by mutant K-Ras were screened using miRNA arrays. miR-199b expression levels were measured by qRT-PCR. The protein expression levels were measured using Western blot and immunohistochemistry. The effects of miR-199b on NSCLC were examined both in vitro and in vivo by overexpressing or inhibiting miR-199b. DNA methylation was measured by bisulfite sequencing.
RESULTS: An inverse correlation was observed between K-Ras mutation status and miR-199b levels in NSCLC specimens and cell lines. The inhibition of miR-199b stimulated NSCLC growth and metastasis, while restoration of miR-199b suppressed K-Ras mutation-driven lung tumorigenesis as well as K-Ras-mutated NSCLC growth and metastasis. miR-199b inactivated ERK and Akt pathways by targeting K-Ras, KSR2, PIK3R1, Akt1, and Rheb1. Furthermore, we determined that mutant K-Ras inhibits miR-199b expression by increasing miR-199b promoter methylation.
CONCLUSION: Our findings suggest that mutant K-Ras plays an oncogenic role through downregulating miR-199b in NSCLC and that overexpression of miR-199b is a novel strategy for the treatment of K-Ras-mutated NSCLC.

Ma Q, Lu Y, Gu Y
ENKUR Is Involved in the Regulation of Cellular Biology in Colorectal Cancer Cells via PI3K/Akt Signaling Pathway.
Technol Cancer Res Treat. 2019; 18:1533033819841433 [PubMed] Free Access to Full Article Related Publications
Colorectal cancer is one of the most prevalent malignancies worldwide. ENKUR is a transient receptor potential canonical-binding protein that acts as a potential regulator or effector of transient receptor potential canonical channels. It also directly interacts with the p85 regulatory subunit of phosphoinositide 3-kinase. However, the role of ENKUR in colorectal cancer remains unclear. In the present study, the expression profiles of ENKUR in the The Cancer Genome Atlas and ONCOMINE databases were analyzed. Significant downregulation of ENKUR was observed in clinical tumor samples of various cancer types, including colorectal cancer. Decreased ENKUR messenger RNA expression and ENKUR protein level were detected in 6 human colorectal cancer cell lines. Silencing of ENKUR in colorectal cancer cells led to enhanced cell proliferation, migration, and invasion, while the opposite effects were achieved in ENKUR-overexpressing cells. Furthermore, ENKUR-underexpressing cells exhibited increased activity of phosphoinositide 3-kinase /Akt signaling pathway. Downregulation of the epithelial marker, E-cadherin, and upregulation of the mesenchymal markers, vimentin and N-cadherin, were detected in ENKUR-underexpressing cells, suggesting the induction of epithelial-mesenchymal transition. In conclusion, the present study demonstrates that ENKUR may be responsible for alterations in the proliferative, migratory, and invasive potential of colorectal cancer cells through possible involvement in the phosphoinositide 3-kinase /Akt signaling pathway.

Huang X, Li Z, Zhang Q, et al.
Circular RNA AKT3 upregulates PIK3R1 to enhance cisplatin resistance in gastric cancer via miR-198 suppression.
Mol Cancer. 2019; 18(1):71 [PubMed] Free Access to Full Article Related Publications
BACKGROUND: Cisplatin (CDDP) treatment is one of the most predominant chemotherapeutic strategies for patients with gastric cancer (GC). A better understanding of the mechanisms of CDDP resistance can greatly improve therapeutic efficacy in patients with GC. Circular RNAs (circRNAs) are a class of noncoding RNAs whose functions are related to the pathogenesis of cancer, but, in CDDP resistance of GC remains unknown.
METHODS: circAKT3 (hsa_circ_0000199, a circRNA originating from exons 8, 9, 10, and 11 of the AKT3 gene) was identified by RNA sequencing and verified by quantitative reverse transcription PCR. The role of circAKT3 in CDDP resistance in GC was assessed both in vitro and in vivo. Luciferase reporter assay, biotin-coupled RNA pull-down and fluorescence in situ hybridization (FISH) were conducted to evaluate the interaction between circAKT3 and miR-198. Functional experiments were measured by western blotting, a cytotoxicity assay, clonogenic assay and flow cytometry.
RESULTS: The expression of circAKT3 was higher in CDDP-resistant GC tissues and cells than in CDDP-sensitive samples. The upregulation of circAKT3 in GC patients receiving CDDP therapy was significantly associated with aggressive characteristics and was an independent risk factor for disease-free survival (DFS). Our data indicated that circAKT3 promotes DNA damage repair and inhibits the apoptosis of GC cells in vivo and in vitro. Mechanistically, we verified that circAKT3 could promote PIK3R1 expression by sponging miR-198.
CONCLUSIONS: circAKT3 plays an important role in the resistance of GC to CDDP. Thus, our results highlight the potential of circAKT3 as a therapeutic target for GC patients receiving CDDP therapy.

Cuevas D, Valls J, Gatius S, et al.
Targeted sequencing with a customized panel to assess histological typing in endometrial carcinoma.
Virchows Arch. 2019; 474(5):585-598 [PubMed] Related Publications
The two most frequent types of endometrial cancer (EC) are endometrioid (EEC) and serous carcinomas (SC). Differential diagnosis between them is not always easy. A subset of endometrial cancers shows misleading microscopical features, which cause problems in differential diagnosis, and may be a good scenario for next-generation sequencing. Previous studies have assessed the usefulness of targeted sequencing with panels of generic cancer-associated genes in EC histological typing. Based on the analysis of TCGA (The Cancer Genome Atlas), EEC and SC have different mutational profiles. In this proof of principle study, we have performed targeted sequencing analysis with a customized panel, based on the TCGA mutational profile of EEC and SC, in a series of 24 tumors (16 EEC and 8 SC). Our panel comprised coding and non-coding sequences of the following genes: ABCC9, ARID1A, ARID5B, ATR, BCOR, CCND1, CDH19, CHD4, COL11A1, CSDE1, CSMD3, CTCF, CTNNB1, EP300, ERBB2, FBXW7, FGFR2, FOXA2, KLLN, KMT2B, KRAS, MAP3K4, MKI67, NRAS, PGAP3, PIK3CA, PIK3R1, PPP2R1A, PRPF18, PTEN, RPL22, SCARNA11, SIN3A, SMARCA4, SPOP, TAF1, TP53, TSPYL2, USP36, and WRAP53. Targeted sequencing validation by Sanger sequencing and immunohistochemistry was performed in a group of genes. POLE mutation status was assessed by Sanger sequencing. The most mutated genes were PTEN (93.7%), ARID1A (68.7%), PIK3CA (50%), and KMT2B (43.7%) for EEC, and TP53 (87.5%), PIK3CA (50%), and PPP2R1A (25%) for SC. Our panel allowed correct classification of all tumors in the two categories (EEC, SC). Coexistence of mutations in PTEN, ARID1A, and KMT2B was diagnostic of EEC. On the other hand, absence of PTEN, ARID1A, and KMT2B mutations in the presence of TP53 mutation was diagnostic of SC. This proof of concept study demonstrates the suitability of targeted sequencing with a customized endometrial cancer gene panel as an additional tool for confirming histological typing.

Tan A, Luo R, Ruan P
miR-495 promotes apoptosis and inhibits proliferation in endometrial cells via targeting PIK3R1.
Pathol Res Pract. 2019; 215(3):594-599 [PubMed] Related Publications
Endometrial cancer (EC) is a huge threat to women's health. The aims of this study were to investigate the role of microRNA (miR)-495 in the proliferation and apoptosis of EC cells in vitro. Reverse transcription-quantitative polymerase chain reaction (RT-qPCR) was performed to detect the mRNA levels. In addition, dual-luciferase reporter assay was used to verified that PIK3R1 was a target of miR-495. After transfection with miR-495 mimics, Cell Counting Kit 8 (CCK-8) assay was performed to evaluate the cell viability of EC cells. The protein expression of PIK3R1, vascular endothelial growth factor (VEGF), Bcl-2, Bax, caspase 3 after transfection was analyzed using western blotting. Furthermore, cell apoptosis rate of EC cells was evaluated by flow cytometry. These results showed that miR-495 was significantly down-regulated in tumor tissues compared with the adjacent normal tissues, while PIK3R1 was up-regulated. The proliferation of the EC cells that were transfected with miR-495 mimics was markedly inhibited, and apoptosis was significantly promoted. In addition, downregulated expression of PIK3R1, Bcl-2, VEGF expression and upregulated expression of Bax and caspase 3 expression were observed after transfected with miR-495 mimic. Together these findings indicated that miR-495 acts as a tumor suppressor gene by directly targeting PIK3R1 at the post-transcriptional level in EC cells in vitro.

Bonazzoli E, Cocco E, Lopez S, et al.
PI3K oncogenic mutations mediate resistance to afatinib in HER2/neu overexpressing gynecological cancers.
Gynecol Oncol. 2019; 153(1):158-164 [PubMed] Article available free on PMC after 01/04/2020 Related Publications
OBJECTIVE: Aberrant expression of HER2/neu and PIK3CA gene products secondary to amplification/mutations are common in high-grade-serous-endometrial (USC) and ovarian-cancers (HGSOC). Because scant information is currently available in the literature on the potential negative effect of PIK3CA mutations on the activity of afatinib, in this study we evaluate for the first time the role of oncogenic PIK3CA mutations as a potential mechanism of resistance to afatinib in HGSOC and USC overexpressing HER2/neu.
METHODS: We used six whole-exome-sequenced primary HGSOC/USC cell-lines and three xenografts overexpressing HER2/neu and harboring mutated or wild-type PIK3CA/PIK3R1 genes to evaluate the role of PI3K-mutations as potential mechanism of resistance to afatinib, an FDA-approved pan-c-erb-inhibitor in clinical trials in USC. Primary-USC harboring wild-type-PIK3CA gene was transfected with plasmids encoding oncogenic PIK3CA-mutations (H1047R/E545K). The effect of afatinib on HER2/PI3K/AKT/mTOR pathway was evaluated by immunoblotting.
RESULTS: We found PI3K wild-type cell-lines to be significantly more sensitive (lower IC
CONCLUSIONS: Oncogenic PI3K mutations may represent a major mechanism of resistance to afatinib. Combinations of c-erb with PIK3CA, AKT or mTOR inhibitors may be necessary to more efficiently block the PIK3CA/AKT/mTOR pathway.

Katase N, Nishimatsu SI, Yamauchi A, et al.
DKK3 knockdown confers negative effects on the malignant potency of head and neck squamous cell carcinoma cells via the PI3K/Akt and MAPK signaling pathways.
Int J Oncol. 2019; 54(3):1021-1032 [PubMed] Related Publications
Dickkopf‑related protein 3 (DKK3), which is a member of the Dickkopf WNT signaling pathway inhibitor family, is considered to be a tumor suppressor, due to its reduced expression in cancer cells and its ability to induce apoptosis when overexpressed by adenovirus. However, our previous study demonstrated alternative functions for DKK3 in head and neck squamous cell carcinoma (HNSCC). Our study reported that DKK3 expression was predominantly upregulated in HNSCC cell lines and tissue samples, and its expression was significantly correlated with poor prognosis. Furthermore, DKK3 overexpression in HNSCC cells significantly increased cancer cell proliferation, migration, invasion and in vivo tumor growth. These data have led to the hypothesis that DKK3 may exert oncogenic functions and may increase the malignant properties of HNSCC. The present study established a stable DKK3 knockdown cell line (HSC‑3 shDKK3) using lentivirus‑mediated short hairpin RNA, and assessed its effects on cancer cell behavior using MTT, migration and invasion assays. In addition, its effects on in vivo tumor growth were assessed using a xenograft model. Furthermore, the molecular mechanisms underlying the effects of DKK3 knockdown were investigated by microarray analysis, pathway analysis and western blotting. Compared with control cells, HSC‑3 shDKK3 cells exhibited significantly reduced proliferation, migration and invasion, and formed significantly smaller tumor masses when subcutaneously transplanted into nude mice. In addition, in HSC‑3 shDKK3 cells, the expression levels of phosphorylated (p)‑protein kinase B (Akt) (Ser473), p‑phosphoinositide 3‑kinase (PI3K) p85 (Tyr467), p‑PI3K p55 (Try199), p‑3‑phosphoinositide‑dependent protein kinase‑1 (PDK1) (Ser241) and total p38 mitogen‑activated protein kinase (MAPK) were reduced. Furthermore, phosphorylation of mechanistic target of rapamycin (mTOR) (Ser2448) was slightly decreased in HSC‑3 shDKK3 cells, which may be due to the increased expression of DEP domain‑containing mTOR‑interacting protein. Conversely, DKK3 overexpression in HSC‑3 shDKK3 cells rescued cellular proliferation, migration and invasion. With regards to expression levels, p‑PI3K and p‑PDK1 expression was not altered, whereas mTOR and p‑p38 MAPK expression was elevated. These data supported the hypothesis and indicated that DKK3 may contribute to the malignant phenotype of HNSCC cells via the PI3K/Akt/mTOR and MAPK signaling pathways.

Ai X, Xiang L, Huang Z, et al.
Overexpression of PIK3R1 promotes hepatocellular carcinoma progression.
Biol Res. 2018; 51(1):52 [PubMed] Article available free on PMC after 01/04/2020 Related Publications
BACKGROUND: Phosphoinositide-3-kinase, regulatory subunit 1 (PIK3R1) could regulate cancer cell proliferation important for cancer cell proliferation; however, its role in Hepatocellular carcinoma (HCC) remains largely unknown. Here, we investigated the role of PIK3R1 in HCC and examined the underlying molecular mechanisms.
METHODS: The expression of PIK3R1 was evaluated by immunohistochemistry and qRT-PCR in a series of HCC tissues. The mRNA and protein expression of PIK3R1 was used by qRT-PCR and western blot assays in a series of human HCC cell lines, and then we choose MHCC97H and HCCLM3 cells as a model to investigate the effect of PIK3R1 on HCC progression. The effects of PIK3R1 knowdown on cell proliferation, migration, apoptosis of HCC were assessed by the MTT assay, clonogenic assays, wound healing assay and flow cytometry in vitro. Western blot assay was performed to assess the expression changes of PI3K/AKT/mTOR signaling pathway.
RESULTS: Our results found that PIK3R1 was highly expressed in HCC tissues compared with adjacent normal tissues. Knockdown of PIK3R1 inhibited the proliferation, migration and promoted apoptosis of HCC cell lines. In addition, we proved that knockdown of PIK3R1 downregulated p-PI3K, p-AKT, and p-mTOR expressions in MHCC97H and HCCLM3 cells.
CONCLUSIONS: In conclusion, PIK3R1 providing potential novel targets for the treatment of HCC.

Williams EA, Miller JJ, Tummala SS, et al.
TERT promoter wild-type glioblastomas show distinct clinical features and frequent PI3K pathway mutations.
Acta Neuropathol Commun. 2018; 6(1):106 [PubMed] Article available free on PMC after 01/04/2020 Related Publications
TERT promoter (TERTp) mutations are found in the majority of World Health Organization (WHO) grade IV adult IDH wild-type glioblastoma (IDH-wt GBM). Here, we characterized the subset of IDH-wt GBMs that do not have TERTp mutations. In a cohort of 121 adult grade IV gliomas, we identified 109 IDH-wt GBMs, after excluding 11 IDH-mutant cases and one H3F3A -mutant case. Within the IDH-wt cases, 16 cases (14.7%) were TERTp wild-type (TERTp-wt). None of the 16 had BRAF V600E or H3F3A G34 hotspot mutations. When compared to TERTp mutants, patients with TERTp-wt GBMs, were significantly younger at first diagnosis (53.2 years vs. 60.7 years, p = 0.0096), and were more frequently found to have cerebellar location (p = 0.0027). Notably, 9 of 16 (56%) of TERTp-wt GBMs contained a PIK3CA or PIK3R1 mutation, while only 16/93 (17%) of TERTp-mutant GBMs harbored these alterations (p = 0.0018). As expected, 8/16 (50%) of TERTp-wt GBMs harbored mutations in the BAF complex gene family (ATRX, SMARCA4, SMARCB1, and ARID1A), compared with only 8/93 (9%) of TERTp-mutant GBMs (p = 0.0003). Mutations in BAF complex and PI3K pathway genes co-occurred more frequently in TERTp-wt GBMs (p = 0.0002), an association that has been observed in other cancers, suggesting a functional interaction indicative of a distinct pathway of gliomagenesis. Overall, our finding highlights heterogeneity within WHO-defined IDH wild-type GBMs and enrichment of the TERTp-wt subset for BAF/PI3K-altered tumors, potentially comprising a distinct clinical subtype of gliomas.

Li X, Han F, Liu W, Shi X
PTBP1 promotes tumorigenesis by regulating apoptosis and cell cycle in colon cancer.
Bull Cancer. 2018; 105(12):1193-1201 [PubMed] Related Publications
Increased expression of polypyrimidine tract-binding protein 1 (PTBP1) has been observed in human ovarian tumors, glioblastomas, and breast cancer, but its biological roles in tumorigenesis is not fully clear. In the present research, we investigated the biological role of PTBP1 in colon cancer. We found that PTBP1 was overexpressed both in colon cancer cell lines and tissues. Tissue microarray analysis (TMA) indicated that low PTBP1 expression predicted a favorable overall survival for colon cancer patients. Using small interfering RNA technology, we found that down-regulation of PTBP1 significantly inhibited colon cancer cell growth/proliferation, and induced cell cycle arrest as well as apoptosis in vitro. Western blot analysis showed that siRNA PTBP1 could up-regulate the expression of cytoC, p53 and Bax as well as down-regulated p85, p-AKT, cyclinD1, CDK4 and Bcl2 compared to the control. Furthermore, Caspase-3 and PARP1 were activated when PTBP1 is knockdown. This study implies that PTBP1 plays an important role in tumorigenesis of colon cancer.

Li D, Pan Y, Huang Y, et al.
PAK5 Induces EMT and Promotes Cell Migration and Invasion by Activating the PI3K/AKT Pathway in Ovarian Cancer.
Anal Cell Pathol (Amst). 2018; 2018:8073124 [PubMed] Article available free on PMC after 01/04/2020 Related Publications
Ovarian cancer is the most lethal gynecologic cancer and currently ranks fifth in causing cancer-related deaths among women. P21

Oda K, Hamanishi J, Matsuo K, Hasegawa K
Genomics to immunotherapy of ovarian clear cell carcinoma: Unique opportunities for management.
Gynecol Oncol. 2018; 151(2):381-389 [PubMed] Related Publications
Ovarian clear cell carcinoma (OCCC) is distinctive from other histological types of epithelial ovarian cancer, with genetic/epigenetic alterations, a specific immune-related molecular profile, and epidemiologic associations with ethnicity and endometriosis. These findings allow for the exploration of unique and specific treatments for OCCC. Two major mutated genes in OCCC are PIK3CA and ARID1A, which are frequently coexistent with each other. Other genes' alterations also contribute to activation of the PI3K (e.g. PIK3R1 and PTEN) and dysregulation of the chromatin remodeling complex (e.g. ARID1B, and SMARKA4). Although the number of focal copy number variations is small in OCCC, amplification is recurrently detected at chromosome 20q13.2 (including ZNF217), 8q, and 17q. Both expression and methylation profiling highlight the significance of adjustments to oxidative stress and inflammation. In particular, up-regulation of HNF-1β resulting from hypomethylation contributes to the switch from anaerobic to aerobic glucose metabolism. Additionally, up-regulation of HNF-1β activates STAT3 and NF-κB signaling, and leads to immune suppression via production of IL-6 and IL-8. Immune suppression may also be induced by the increased expression of PD-1, Tim-3 and LAG3. Mismatch repair deficient (microsatellite instable) tumors as found in Lynch syndrome also induce immune suppression in some OCCC. In a recent phase II clinical trial in heavily-treated platinum-resistant ovarian cancer, two out of twenty cases with a complete response to the anti-PD-1 antibody, nivolumab, were OCCC subtypes. Thus, the immune-suppressive state resulting from both genetic alterations and the unique tumor microenvironment may be associated with sensitivity to immune checkpoint inhibitors in OCCC. In this review, we highlight recent update and progress in OCCC from both the genomic and immunologic points of view, addressing the future candidate therapeutic options.

Griffith OL, Spies NC, Anurag M, et al.
The prognostic effects of somatic mutations in ER-positive breast cancer.
Nat Commun. 2018; 9(1):3476 [PubMed] Article available free on PMC after 01/04/2020 Related Publications
Here we report targeted sequencing of 83 genes using DNA from primary breast cancer samples from 625 postmenopausal (UBC-TAM series) and 328 premenopausal (MA12 trial) hormone receptor-positive (HR+) patients to determine interactions between somatic mutation and prognosis. Independent validation of prognostic interactions was achieved using data from the METABRIC study. Previously established associations between MAP3K1 and PIK3CA mutations with luminal A status/favorable prognosis and TP53 mutations with Luminal B/non-luminal tumors/poor prognosis were observed, validating the methodological approach. In UBC-TAM, NF1 frame-shift nonsense (FS/NS) mutations were also a poor outcome driver that was validated in METABRIC. For MA12, poor outcome associated with PIK3R1 mutation was also reproducible. DDR1 mutations were strongly associated with poor prognosis in UBC-TAM despite stringent false discovery correction (q = 0.0003). In conclusion, uncommon recurrent somatic mutations should be further explored to create a more complete explanation of the highly variable outcomes that typifies ER+ breast cancer.

Ye Y, Li SL, Wang SY
Construction and analysis of mRNA, miRNA, lncRNA, and TF regulatory networks reveal the key genes associated with prostate cancer.
PLoS One. 2018; 13(8):e0198055 [PubMed] Article available free on PMC after 01/04/2020 Related Publications
PURPOSE: Prostate cancer (PCa) causes a common male urinary system malignant tumour, and the molecular mechanisms of PCa are related to the abnormal regulation of various signalling pathways. An increasing number of studies have suggested that mRNAs, miRNAs, lncRNAs, and TFs could play important roles in various biological processes that are associated with cancer pathogenesis. This study aims to reveal functional genes and investigate the underlying molecular mechanisms of PCa with bioinformatics.
METHODS: Original gene expression profiles were obtained from the GSE64318 and GSE46602 datasets in the Gene Expression Omnibus (GEO). We conducted differential screens of the expression of genes (DEGs) between two groups using the online tool GEO2R based on the R software limma package. Interactions between differentially expressed miRNAs, mRNAs and lncRNAs were predicted and merged with the target genes. Co-expression of miRNAs, lncRNAs and mRNAs was selected to construct mRNA-miRNA-lncRNA interaction networks. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analyses were performed for the DEGs. Protein-protein interaction (PPI) networks were constructed, and transcription factors were annotated. Expression of hub genes in the TCGA datasets was verified to improve the reliability of our analysis.
RESULTS: The results demonstrate that 60 miRNAs, 1578 mRNAs and 61 lncRNAs were differentially expressed in PCa. The mRNA-miRNA-lncRNA networks were composed of 5 miRNA nodes, 13 lncRNA nodes, and 45 mRNA nodes. The DEGs were mainly enriched in the nuclei and cytoplasm and were involved in the regulation of transcription, related to sequence-specific DNA binding, and participated in the regulation of the PI3K-Akt signalling pathway. These pathways are related to cancer and focal adhesion signalling pathways. Furthermore, we found that 5 miRNAs, 6 lncRNAs, 6 mRNAs and 2 TFs play important regulatory roles in the interaction network. The expression levels of EGFR, VEGFA, PIK3R1, DLG4, TGFBR1 and KIT were significantly different between PCa and normal prostate tissue.
CONCLUSION: Based on the current study, large-scale effects of interrelated mRNAs, miRNAs, lncRNAs, and TFs established a new prostate cancer network. In addition, we conducted functional module analysis within the network. In conclusion, this study provides new insight for exploration of the molecular mechanisms of PCa and valuable clues for further research into the process of tumourigenesis and its development in PCa.

Ramos J, Das J, Felty Q, et al.
NRF1 motif sequence-enriched genes involved in ER/PR -ve HER2 +ve breast cancer signaling pathways.
Breast Cancer Res Treat. 2018; 172(2):469-485 [PubMed] Related Publications
Nuclear respiratory factor 1 (NRF1) transcription factor has recently been shown to control breast cancer progression. However, mechanistic aspects by which NRF1 may contribute to susceptibility to different breast tumor subtypes are still not fully understood. Since transcriptional control of NRF1 seems to be dependent on epidermal growth factor receptor signaling, herein, we investigated the role of NRF1 in estrogen receptor/progesterone receptor negative, but human epidermal growth factor receptor 2-positive (ER/PR -ve HER2 +ve) breast cancer. We found that both mRNA and protein levels of NRF1 and its transcriptional activity were significantly higher in ER/PR -ve HER2 +ve breast cancer samples compared to normal breast tissues. This was consistent with our observation of higher NRF1 protein expression in the experimental model of HER2+ breast cancer brain metastasis. To identify network-based pathways involved in the susceptibility to the ER/PR -ve HER2 +ve breast cancer subtype, the NRF1 transcriptional regulatory genome-wide landscape was analyzed using the approach consisting of a systematic integration of ChIP DNA-seq, RNA-Microarray, NRF1 protein-DNA motif binding, signal pathway analysis, and Bayesian machine learning. Our findings show that a high percentage of known HER2+ breast cancer susceptibility genes, including EGFR, IGFR, and E2F1, are under transcriptional control of NRF1. Promoters of several genes from the KEGG HER2+ breast cancer pathway and 11 signaling pathways linked to 6 hallmarks of cancer contain the NRF1 motif. By pathway analysis, key breast cancer hallmark genes of epithelial-mesenchymal transition, stemness, cell apoptosis, cell cycle regulation, chromosomal integrity, and DNA damage/repair were highly enriched with NRF1 motifs. In addition, we found using Bayesian network-based machine learning that 30 NRF1 motif-enriched genes including growth factor receptors-FGFR1, IGF1R; E2Fs transcription factor family-E2F1, E2F3; MAPK pathway-SHC2, GRB2, MAPK1; PI3K-AKT-mTOR signaling pathway-PIK3CD, PIK3R1, PIK3R3, RPS6KB2; WNT signaling pathway-WNT7B, DLV1, DLV2, GSK3B, NRF1, and DDB2, known for its role in DNA repair and involvement in early events associated with metastatic progression of breast cancer cells, were associated with HER2-amplified breast cancer. Machine learning search further revealed that the likelihood of HER2-positive breast cancer is almost 100% in a patient with the high NRF1 expression combined with expression patterns of high E2F3, GSK3B, and MAPK1, low or no change in E2F1 and FGFR1, and high or no change in PIK3R3. In summary, our findings suggest novel roles of NRF1 and its regulatory networks in susceptibility to the ER/PR -ve HER2 +ve aggressive breast cancer subtype. Clinical confirmation of our machine learned Bayesian networks will have significant impact on our understanding of the role of NRF1 as a valuable biomarker for breast cancer diagnosis and prognosis as well as provide strong rationale for future studies to develop NRF1 signaling-based therapeutics to target HER2+ breast cancer.

Nassan MA, Soliman MM, Ismail SA, El-Shazly S
Effect of
Biosci Rep. 2018; 38(6) [PubMed] Article available free on PMC after 01/04/2020 Related Publications
BACKGROUND: Breast cancer is one of the most prevalent types of cancer and a leading cause of death in women.
MATERIALS AND METHODS: An experimental model of breast cancer was induced in female albino rats using single intragastric dose of 7, 12 dimethylbenz (α) anthracene (DMBA) in sesame oil (50 mg/kg b.wt). Four months after DMBA administration, incidence of breast cancer was confirmed by measuring cancer antigen 15-3 (CA15-3) serum levels.
RESULTS: Level of CA15-3 was normalized in DMBA group administered TOE for 4 weeks. Administration of DMBA increased expression of

Qi W, Sun L, Liu N, et al.
Tetraspanin family identified as the central genes detected in gastric cancer using bioinformatics analysis.
Mol Med Rep. 2018; 18(4):3599-3610 [PubMed] Article available free on PMC after 01/04/2020 Related Publications
Gastric cancer has become a serious disease in the past decade. It has the second highest mortality rate among the four most common cancer types, leading to ~700,000 mortalities annually. Previous studies have attempted to elucidate the underlying biological mechanisms of gastric cancer. The present study aimed to obtain useful biomarkers and to improve the understanding of gastric cancer mechanisms at the genetic level. The present study used bioinformatics analysis to identify 1,829 differentially expressed genes (DEGs) which were obtained from the GSE54129 dataset. Using protein‑protein interaction information from the Search Tool for the Retrieval of Interacting Genes database, disease modules were constructed for gastric cancer using Cytoscape software. In the Gene Ontology analysis of biology processes, upregulated genes were significantly enriched in 'extracellular matrix organization', 'cell adhesion' and 'inflammatory response', whereas downregulated DEGs were significantly enriched in 'xenobiotic metabolic process', 'oxidation‑reduction process' and 'steroid metabolic process'. During Kyoto Encyclopedia of Genes and Genomes analysis, upregulated DEGs were significantly enriched in 'extracellular matrix‑receptor interaction', 'focal adhesion' and 'PI3K‑Akt signaling pathway', whereas the downregulated DEGs were significantly enriched in 'chemical carcinogenesis', 'metabolism of xenobiotics by cytochrome P450' and 'peroxisome'. The present study additionally identified 10 hub genes from the DEGs: Tumor protein p53 (TP53), C‑X‑C motif chemokine ligand 8 (CXCL8), tetraspanin 4 (TSPAN4), lysophosphatidic acid receptor 2 (LPAR2), adenylate cyclase 3 (ADCY3), phosphoinositide‑3‑kinase regulatory subunit 1 (PIK3R1), neuromedin U (NMU), C‑X‑C motif chemokine ligand (CXCL12), fos proto‑oncogene, AP‑1 transcription factor subunit (FOS) and sphingosine‑1‑phosphate receptor 1 (S1PR1), which have high degrees with other DEGs. The survival analysis revealed that the high expression of ADCY3, LPAR2, S1PR1, TP53 and TSPAN4 was associated with a lower survival rate, whereas high expression of CXCL8, FOS, NMU and PIK3R1 was associated with a higher survival rate. No significant association was identified between CXCL12 and survival rate. Additionally, TSPAN1 and TSPAN8 appeared in the top 100 DEGs. Finally, it was observed that 4 hub genes were highly expressed in gastric cancer tissue compared with para‑carcinoma tissue in the 12 patients; the increased TSPAN4 was significant (>5‑fold). Tetraspanin family genes may be novel biomarkers of gastric cancer. The findings of the present study may improve the understanding of the molecular mechanisms underlying the development of gastric cancer.

Kennedy S, Rice M, Toomey S, et al.
An insight into the molecular genetics of a uveal melanoma patient cohort.
J Cancer Res Clin Oncol. 2018; 144(10):1861-1868 [PubMed] Related Publications
BACKGROUND/AIMS: Uveal melanoma (UM) is a highly aggressive malignancy and presents a clinically significant unmet need in cancer therapeutics. The aim of this study was to identify previously unreported mutations in UM among an Irish cohort of patients which may have potential clinical relevance.
METHODS: DNA was extracted from 36 intraocular melanoma patient samples and 4 metastatic melanoma samples among the patient cohort by microdissection from formalin-fixed paraffin embedded tissue blocks and underwent genotyping to test for known single nucleotide polymorphisms in 42 cancer associated genes. These mutations were analysed using a custom-designed sequenom panel.
RESULTS: Using high-throughput genotyping, mutually exclusive GNAQ and GNA11 mutations were detected in 31 of 34 UM patients together with a number of non-synonymous changes in established cancer driver genes, PHLPP2, MET, PIK3R1 and IDH-1, variants which have not been previously associated with UM.
CONCLUSION: Given the lack of knowledge regarding the clinical relevance of the variants identified in this UM cohort and their likely pathogenic nature in other cancers, further studies of the functional impact of these variant mutations are warranted to establish possible previously, undescribed roles in UM pathogenesis, which may provide additional targets for future therapies.

Krings G, Chen YY
Genomic profiling of metaplastic breast carcinomas reveals genetic heterogeneity and relationship to ductal carcinoma.
Mod Pathol. 2018; 31(11):1661-1674 [PubMed] Related Publications
Metaplastic breast carcinomas comprise a histologically heterogenous group of tumors. Although most are triple (estrogen/progesterone receptor, HER2) negative, these rare tumors are clinicopathologically distinct from other triple negative carcinomas and may be aggressive with worse chemotherapy responses. On the other hand, metaplastic carcinomas are histologically diverse, which is reflected in gene expression differences among subtypes. Whether metaplastic carcinomas are genetically distinct from other triple negative cancers and whether genetic differences underlie histologic subtypes remains poorly understood. We sequenced 408 cancer-related genes in 28 metaplastic carcinomas, including chondroid matrix-producing carcinomas (n = 10), spindle cell carcinomas (n = 5), and carcinomas with squamous (n = 5), mixed spindle/squamous (n = 5), and mixed metaplastic (n = 3) differentiation. Metaplastic carcinomas were highly enriched for PIK3CA/PIK3R1 (61%) and Ras-Map kinase (25%) pathway aberrations compared to other triple negative carcinomas (TCGA dataset 14%, p < 0.001 and 7%, p = 0.005, respectively) and harbored a high frequency of TP53 (64%) and TERT promoter (25%) mutations, but this varied among subtypes. Chondroid-matrix producing carcinomas lacked PI-3 kinase and Ras-Map kinase aberrations and TERT promoter mutations, compared to 100%, 39%, and 39% of non-matrix-producing tumors, respectively. TERT promoter mutations were enriched (47%) in spindle cell carcinomas and tumors with squamous or spindle/squamous differentiation. Spindle cell carcinomas lacked TP53 mutations, in contrast to other subtypes (78%, p = 0.003). Separate analysis of paired ductal carcinoma in situ and metaplastic carcinoma revealed shared clonality in all cases (n = 8). Activating PI-3 kinase and Ras pathway mutations were early events, and inactivating mutations in tumor suppressors including RB1, CDKN2A, and TP53 were associated with invasion in individual cases. Metaplastic components of two tumors showed genetic progression from separately sequenced paired invasive ductal carcinoma. The findings suggest that metaplastic carcinomas are genetically distinct from other triple negative breast cancers and highlight genetic heterogeneity that broadly correlates with histologic subtype. Heterologous elements progress from associated ductal carcinoma.

Geyer FC, Li A, Papanastasiou AD, et al.
Recurrent hotspot mutations in HRAS Q61 and PI3K-AKT pathway genes as drivers of breast adenomyoepitheliomas.
Nat Commun. 2018; 9(1):1816 [PubMed] Article available free on PMC after 01/04/2020 Related Publications
Adenomyoepithelioma of the breast is a rare tumor characterized by epithelial-myoepithelial differentiation, whose genetic underpinning is largely unknown. Here we show through whole-exome and targeted massively parallel sequencing analysis that whilst estrogen receptor (ER)-positive adenomyoepitheliomas display PIK3CA or AKT1 activating mutations, ER-negative adenomyoepitheliomas harbor highly recurrent codon Q61 HRAS hotspot mutations, which co-occur with PIK3CA or PIK3R1 mutations. In two- and three-dimensional cell culture models, forced expression of HRAS

Jiang H, Dong L, Gong F, et al.
Inflammatory genes are novel prognostic biomarkers for colorectal cancer.
Int J Mol Med. 2018; 42(1):368-380 [PubMed] Article available free on PMC after 01/04/2020 Related Publications
Inflammatory genes serve a crucial role in the pathogenesis of inflammation‑associated tumors. However, as recent studies have mainly focused on the effects of single inflammatory genes on colorectal cancer (CRC), but not on the global interactions between genes, the underlying mechanisms between inflammatory genes and CRC remain unclear. In the current study, two inflammation‑associated networks were constructed based on inflammatory genes, differentially expressed genes (DEGs) in CRC vs. normal samples, and protein‑protein interactions (PPIs). These networks included an inflammation‑related neighbor network (IRNN) and an inflammation‑related DEG network (IRDN). Notably, the results indicated that the inflammatory genes served as important CRC‑associated genes in the IRNN. Certain inflammatory genes were more likely to be network hubs and exhibited higher betweenness centralities, indicating that these inflammatory hub genes had central roles in the communication between genes in the IRNN. By contrast, in the IRDN, functional enrichment analysis revealed that genes were enriched in numerous cancer‑associated functions and pathways. Subsequently, 14 genes in a module were identified in the IRDN as the potential biomarkers associated with disease‑free survival (DFS) in CRC patients in the GSE24550 dataset, the prognosis of which was further validated using three independent datasets (GSE24549, GSE34551 and GSE103479). All 14 genes (including BCAR1, CRK, FYN, GRB2, LCP2, PIK3R1, PLCG1, PTK2, PTPN11, PTPN6, SHC1, SOS1, SRC and SYK) in this module were inflammatory genes, emphasizing the critical role of inflammation in CRC. In conclusion, these findings based on integrated inflammation‑associated networks provided a novel insight that may help elucidate the inflammation‑mediated mechanisms involved in CRC.

Chen L, Yang L, Yao L, et al.
Characterization of PIK3CA and PIK3R1 somatic mutations in Chinese breast cancer patients.
Nat Commun. 2018; 9(1):1357 [PubMed] Article available free on PMC after 01/04/2020 Related Publications
Deregulation of the phosphoinositide 3-kinase (PI3K) pathway contributes to the development and progression of tumors. Here, we determine that somatic mutations in PIK3CA (44%), PIK3R1 (17%), AKT3 (15%), and PTEN (12%) are prevalent and diverse in Chinese breast cancer patients, with 60 novel mutations identified. A high proportion of tumors harbors multiple mutations, especially PIK3CA plus PIK3R1 mutations (9.0%). Next, we develop a recombination-based mutation barcoding (ReMB) library for impactful mutations conferring clonal advantage in proliferation and drug responses. The highest-ranking PIK3CA and PIK3R1 mutations include previously reported deleterious mutations, as well as mutations with unknown significance. These PIK3CA and PIK3R1 impactful mutations exhibit a mutually exclusive pattern, leading to oncogenesis and hyperactivity of PI3K pathway. The PIK3CA impactful mutations are tightly associated with hormone receptor positivity. Collectively, these findings advance our understanding of PI3K impactful mutations in breast cancer and have important implications for PI3K-targeted therapy in precision oncology.

Dornan GL, Burke JE
Molecular Mechanisms of Human Disease Mediated by Oncogenic and Primary Immunodeficiency Mutations in Class IA Phosphoinositide 3-Kinases.
Front Immunol. 2018; 9:575 [PubMed] Article available free on PMC after 01/04/2020 Related Publications
The signaling lipid phosphatidylinositol 3,4,5, trisphosphate (PIP

Gao ZJ, Yuan WD, Yuan JQ, et al.
miR-486-5p functions as an oncogene by targeting PTEN in non-small cell lung cancer.
Pathol Res Pract. 2018; 214(5):700-705 [PubMed] Related Publications
PURPOSE: Lung cancer, the leading cause of cancer-related death worldwide, shows a poor 5-year overall survival rate. In our previous study, we demonstrated that miR-486-5p can be a potential blood-based biomarker for early diagnosis and recurrence prediction of non-small cell lung cancer (NSCLC). The aim of the present study was to investigate the possible roles and related target genes of miR-486-5p in NSCLC progression.
METHODS: pcDNA3.1(+)/Pri-miR486 recombinant plasmid and miR-486-5p inhibitor were transfected into NSCLC cells and theirs effects were evaluated by qRT-PCR. Then, MTT assay and Colony formation assay were performed to determine the potential roles of miR-486-5p played on NSCLC cellular proliferation and cloning in vitro. We also initially investigated the target genes of miR-486-5p by using bioinformatic methods, qRT-PCR and western blot.
RESULTS: pcDNA3.1(+)/Pri-miR486 recombinant plasmid significantly upregulated the expression of miR-486-5p, while miR-486-5p inhibitor significantly downregulated its expression. Upregulation of miR-486-5p promoted the cellular proliferation and cloning, while miR-486-5p silencing restrained the cellular proliferation and cloning. Furthermore, four potential target genes (PIK3R1, PTEN, MAP3K7 and FOXO1) of miR-486-5p were screened out. Finally, we found that upregulation of miR-486-5p in NSCLC cells significantly reduced PTEN and increased AKT expression levels, whereas miR-486-5p silencing increased PTEN and reduced AKT expression. Therefore, we believe that miR-486-5p can regulate PTEN-PI3 K/AKT signaling.
CONCLUSIONS: miR-486-5p acts as an oncogene in the progression of NSCLC by influencing PTEN-PI3 K/AKT signaling. miR-486-5p may provide potential therapeutic targets for NSCLC.

Inoue A, Mizushima T, Wu X, et al.
A miR-29b Byproduct Sequence Exhibits Potent Tumor-Suppressive Activities via Inhibition of NF-κB Signaling in
Mol Cancer Ther. 2018; 17(5):977-987 [PubMed] Related Publications
We previously demonstrated that miR-29b-3p is a hopeful miRNA-based therapy against colorectal cancer. In this study, we aimed to clarify a value of miR-29b-1-5p as a next-generation treatment, especially for

Kim S, Lee E, Jung J, et al.
microRNA-155 positively regulates glucose metabolism via PIK3R1-FOXO3a-cMYC axis in breast cancer.
Oncogene. 2018; 37(22):2982-2991 [PubMed] Article available free on PMC after 01/04/2020 Related Publications
MicroRNA is an endogenous, small RNA controlling multiple target genes and playing roles in various biological processes including tumorigenesis. Here, we addressed the function of miR-155 using LC-MS/MS-based metabolic profiling of miR-155 deficient breast cancer cells. Our results revealed the loss of miR-155 hampers glucose uptake and glycolysis, via the down-regulation of glucose transporters and metabolic enzymes including HK2, PKM2, and LDHA. We showed this is due to the down-regulation of cMYC, controlled through phosphoinositide-3-kinase regulatory subunit alpha (PIK3R1)-PDK1/AKT-FOXO3a pathway. UTR analysis of the PIK3R1 and FOXO3a indicated miR-155 directly represses these genes. A stable expression of miR-155 in patient-derived cells (PDCs) showed activated glucose metabolism whereas a stable inhibition of miR-155 reduced in vivo tumor growth with retarded glucose metabolism. Furthermore, analysis of 50 triple-negative breast cancer (TNBC) specimens and specific uptake value (SUV) of PET images revealed a positive correlation between miR-155 level and glucose usage in human breast tumors via PIK3R1-PDK/AKT-FOXO3a-cMYC axis. Collectively, these data demonstrate the miR-155 is a key regulator of glucose metabolism in breast cancer.

Xie JJ, Jiang YY, Jiang Y, et al.
Super-Enhancer-Driven Long Non-Coding RNA LINC01503, Regulated by TP63, Is Over-Expressed and Oncogenic in Squamous Cell Carcinoma.
Gastroenterology. 2018; 154(8):2137-2151.e1 [PubMed] Related Publications
BACKGROUND & AIMS: Long non-coding RNAs (lncRNAs) are expressed in tissue-specific pattern, but it is not clear how these are regulated. We aimed to identify squamous cell carcinoma (SCC)-specific lncRNAs and investigate mechanisms that control their expression and function.
METHODS: We studied expression patterns and functions of 4 SCC-specific lncRNAs. We obtained 113 esophageal SCC (ESCC) and matched non-tumor esophageal tissues from a hospital in Shantou City, China, and performed quantitative reverse transcription polymerase chain reaction assays to measure expression levels of LINC01503. We collected clinical data from patients and compared expression levels with survival times. LINC01503 was knocked down using small interfering RNAs and oligonucleotides in TE7, TE5, and KYSE510 cell lines and overexpressed in KYSE30 cells. Cells were analyzed by chromatin immunoprecipitation sequencing, luciferase reporter assays, colony formation, migration and invasion, and mass spectrometry analyses. Cells were injected into nude mice and growth of xenograft tumors was measured. LINC01503 interaction with proteins was studied using fluorescence in situ hybridization, RNA pulldown, and RNA immunoprecipitation analyses.
RESULTS: We identified a lncRNA, LINC01503, which is regulated by a super enhancer and is expressed at significantly higher levels in esophageal and head and neck SCCs than in non-tumor tissues. High levels in SCCs correlated with shorter survival times of patients. The transcription factor TP63 bound to the super enhancer at the LINC01503 locus and activated its transcription. Expression of LINC01503 in ESCC cell lines increased their proliferation, colony formation, migration, and invasion. Knockdown of LINC01503 in SCC cells reduced their proliferation, colony formation, migration, and invasion, and the growth of xenograft tumors in nude mice. Expression of LINC01503 in ESCC cell lines reduced ERK2 dephosphorylation by DUSP6, leading to activation of ERK signaling via MAPK. LINC01503 disrupted the interaction between EBP1 and the p85 subunit of PI3K, increasing AKT signaling.
CONCLUSIONS: We identified an lncRNA, LINC01503, which is increased in SCC cells compared with non-tumor cells. Increased expression of LINC01503 promotes ESCC cell proliferation, migration, invasion, and growth of xenograft tumors. It might be developed as a biomarker of aggressive SCCs in patients.

Xu S, Li Y, Lu Y, et al.
LZTS2 inhibits PI3K/AKT activation and radioresistance in nasopharyngeal carcinoma by interacting with p85.
Cancer Lett. 2018; 420:38-48 [PubMed] Related Publications
Phosphoinositide 3-kinase (PI3K) activity is aberrantly activated in nasopharyngeal carcinoma. However, the underlying mechanisms remain unclear. Here, we found that Leucine zipper tumor suppressor 2 (LZTS2) was downregulated and predicted poor prognosis in nasopharyngeal carcinoma patients. Furthermore, we identified the PI3K subunit p85 as a novel LZTS2-interacting protein using an unbiased proteomics approach. Moreover, we demonstrated that LZTS2 competes with p110 for p85 binding and inhibits activation of the PI3K/AKT signaling pathway. Functionally, we showed that LZTS2 suppresses tumorigenesis and radioresistance in nasopharyngeal carcinoma in a p85-dependent manner. Taken together, our results not only provide understanding of the molecular mechanisms by which PI3K/AKT signaling is activated but also suggest that targeting the LZTS2/PI3K/AKT signaling axis is a promising therapeutic strategy for radiosensitization of nasopharyngeal carcinoma.

Qi L, Sun K, Zhuang Y, et al.
Study on the association between PI3K/AKT/mTOR signaling pathway gene polymorphism and susceptibility to gastric cancer.
J BUON. 2017 Nov-Dec; 22(6):1488-1493 [PubMed] Related Publications
PURPOSE: Excessive activation of PI3K/AKT/mTOR signaling pathway is one of the most common changes in human cancers, and single nucleotide polymorphisms (SNPs) existing in its functional region can affect the occurrence process of a variety of cancers. This study aimed to screen out the SNPs associated with susceptibility to gastric cancer in the PI3K/AKT/mT0R signaling pathway.
METHODS: In this case-control study, the tagging SNPs in the promoter region5'-UTR, exon region or 3'-UTR of PIK3CA, PIK3CB, PIK3R1, PIK3R2, PIK3R3, AKT1, AKT2, AKT3 and mTOR genes were screened out. The relationship between the genetic variation of PI3K/AKT/mT0R signaling pathway genes and the susceptibility to gastric cancer in Chinese Han population was investigated by this casecontrol study.
RESULTS: The results showed that the polymorphisms of the two loci, PIK3R3 rs7536272 (Additive model: OR=1.16, 95% CI=1.01-1.35) and mTOR rs2295080 (GG vs TT: OR=0.75, 95% CI=0.60-0.94; Additive model: OR=0.78, 95% CI=0.66- 0.93), were associated with the risk of gastric cancer in the studied population and there was a combined effect between the two loci (ptrend=0.005).
CONCLUSIONS: In conclusion, the polymorphisms of the two loci, PIK3R3 rs7536272 and mTOR rs2295080, on the PI3K/AKT/mTOR signaling pathway genes are associated with genetic susceptibility to gastric cancer in Chinese population.

Wu D, Lu P, Mi X, Miao J
Downregulation of miR-503 contributes to the development of drug resistance in ovarian cancer by targeting PI3K p85.
Arch Gynecol Obstet. 2018; 297(3):699-707 [PubMed] Related Publications
OBJECTIVE: Cisplatin is an important chemotherapeutic agent frequently used in the treatment of ovarian cancer. However, resistance to cisplatin is an obstacle to the treatment of ovarian cancer. Recently, many studies have demonstrated that microRNAs (miRNAs) are involved in the drug resistance of ovarian cancer cells. In this study, we explored the role of miR-503 in cisplatin-resistant ovarian cancer.
MATERIALS AND METHODS: To investigate the relationship between miR-503 expression and the sensitivity of ovarian cancer cells to cisplatin, the cells were transfected with miR-503 mimics/inhibitors. The relative expression of miR-503 RNA and its targeted gene PI3K mRNA were detected by real-time PCR (RT-PCR). Western blot was used to measure relevant protein levels. Flow cytometry and CCK-8 assay were used to analyze cell proliferation and apoptosis.
RESULTS: MiR-503 expression was significantly downregulated in cisplatin-resistant ovarian cancer cell line SKOV3/DDP compared with parental SKOV3. Over-expression and knock-down of miR-503 partially regulated apoptotic activity and changed the cisplatin resistance of ovarian cancer cells. In exploring the underlying mechanisms of miR-503 in ovarian cancer cells' resistance to cisplatin, we found that miR-503 can directly target PI3K p85 and participates in the regulation of the PI3K/Akt signaling pathway. In vivo, miR-503 agomirs combined with cisplatin treatment significantly reduced the growth of tumors compared with cisplatin alone.
CONCLUSIONS: Our data suggest that miR-503 might be a sensitizer to cisplatin treatment in ovarian cancer by targeting PI3K p85, thus giving a new insight into developing therapeutic strategies to overcome cisplatin resistance in ovarian cancer.

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