AT-rich Interactive Domain 1A Research Articles

Prognostic role of ARID1A negative expression in gastric cancer

AT-rich interactive domain 1A (ARID1A) functions as a tumor suppressor and several therapeutic targets in ARID1A-mutated cancers are under development. Here, we investigated the prognostic value of ARID1A for gastric cancer and its association with expression of PD-L1 and p53. ARID1A expression was examined by immunohistochemistry and negative expression of ARID1A was detected in 39 (19.5%) of 200 cases in a test cohort and in 40 (18.2%) of 220 cases in a validation cohort. Negative expression of ARID1A was associated with worse overall survival in undifferentiated cases, particularly early-stage cases. Negative expression of ARID1A was detected in 11 (50%) of 22 PD-L1-positive cases and in 68 (17.1%) of 398 PD-L1-negative cases in a combined cohort. Negative expression of ARID1A was detected in 45 (22%) of 205 p53-positive cases and in 34 (15.8%) of 215 p53-negative cases in a combined cohort. In addition, expression of EZH2, a potential synthetic lethal target in ARID1A-mutated tumors, was detected in 79 ARID1A-negative cases. An ARID1A-knockdown gastric cancer cell line was subjected to microarray analysis, but no actionable targets or pathways were identified. The present results indicate that ARID1A may serve as an early-stage prognostic biomarker for undifferentiated gastric cancer.

Molecular association of functioning stroma with carcinoma cells in the ovary: A preliminary study.

The cancer stroma serves an important role in tumour behaviours, including invasion, metastasis, and response to chemotherapy. The stroma of ovarian carcinoma is sometimes specialized, with luteinisation and/or hyperthecosis, and is designated as the 'functioning stroma' because it exerts endocrine function and produces sex steroid hormones. In the present study, 14 ovarian cancers with functioning stroma, comprising 7 endometrioid carcinomas and 7 clear cell carcinomas, were analysed to evaluate the molecular association of the functioning stroma with carcinoma cells. The median age of the patients was 67 years (range, 52-85 years); 13 patients were postmenopausal, and one was in perimenopause. Serum oestrogen values ranged from 10 to 129 ng/ml, with a median of 51 ng/ml. Sequence abnormalities in AT-rich interaction domain 1A (ARID1A), phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit α (PIK3CA), Kirsten rat sarcoma viral proto-oncogene (KRAS) and phosphatase and tensin homolog (PTEN) were examined in whole tumours. For cancers positive for sequence abnormalities, their localization in carcinoma cells and/or stromal cells was examined. A total of 8 mutations - ARID1A (L2155L), PIK3CA (H1047R), KRAS (Q12V, E31K, Q61L), and PTEN (C105fs*8) - were identified in the whole tumours of 5 patients. Seven of these eight mutations were detected only in carcinoma cells. However, one case of endometrioid carcinoma had a KRAS (E31K) mutation in both carcinoma and stromal cells. In conclusion, although functioning stromal cells of ovarian cancer are usually thought to be non-neoplastic, some may share an origin with carcinoma cells.

Expression and significance of EBV, ARID1A and PIK3CA in gastric carcinoma.

AT-rich interaction domain 1A (ARID1A) and phosphatidylinositol-4,5-bisphosphate 3-kinase catalytic subunit α (PIK3CA) serve important roles in the formation and development of numerous malignancies including gastric cancer. Accumulating evidence has demonstrated that Epstein-Barr virus (EBV) is a pathogenic virus associated with gastric cancer. The present study aimed to investigate the association between EBV infection, and the expression levels of ARID1A and PIK3CA in gastric cancer. EBER in situ hybridization was performed to detect EBV infection. Immunohistochemistry was used to assess the expression levels of ARID1A and PIK3CA in gastric cancer and adjacent normal tissues. A total of 58 gastric cancer and 10 adjacent normal tissues were tested for genetic mutations via single nucleotide polymorphism genotyping assays. Fluorescent polymerase chain reaction was used to detect EBV infection; 9.3% (28/300) of gastric cancer samples were positive for EBV, whereas, all adjacent normal tissues were negative. ARID1A and PIK3CA were negatively correlated in gastric cancer (r=−0.167). The expression levels of ARID1A and PIK3CA in gastric cancer were significantly associated with the depth of invasion of gastric cancer. A total of 62.1% (36/58) of tumor samples exhibited mutations in ARID1A, whereas, 13.8% (8/58) presented mutations in PIK3CA. Notably, EBV-associated gastric cancer (EBVaGC) samples with PIK3CA mutations additionally exhibited ARID1A mutations. Although in the present study it was identified that ARID1A and PIK3CA were negatively correlated in EBVaGC, further studies are required to investigate the association among ARID1A, PIK3CA and EBV in gastric cancer.

The Role of ARID1A in Endometrial Cancer and the Molecular Pathways Associated With Pathogenesis and Cancer Progression.

AT-rich interaction domain 1A gene (ARID1A) encodes for a subunit of the switch/sucrose non-fermentable (SWI/SNF) complex, a chromatin remodeling complex, and it has been implicated in the pathogenesis of various cancer types. In this review, we discuss how ARID1A is linked to endometrial cancer and what molecular pathways are affected by mutation or inhibition of ARID1A. We also discuss the potential use of ARID1A not only as a prognostic biomarker, but also as a target for therapeutic interventions.

Upregulation of lncRNA DGCR5 correlates with better prognosis and inhibits bladder cancer progression via transcriptionally facilitating P21 expression.

Mounting studies show that long noncoding RNAs (lncRNAs) could affect human cancer progression, including bladder cancer (BCa). LncRNA DiGeorge syndrome critical region gene 5 (DGCR5) has been proven to be involved in lung cancer, pancreatic ductal adenocarcinoma, and hepatocellular carcinoma. However, the function of DGCR5 in BCa remains largely unknown. Here, we found that DGCR5 expression was significantly downregulated in BCa tissues compared with adjacent normal tissues. Higher expression of DGCR5 predicted higher survival rate in BCa patients. Functional experiments indicated that DGCR5 overexpression markedly inhibited that proliferation, colony formation, and cell-cycle progression in BCa cells. Furthermore, ectopic expression of DGCR5 led to decreased BCa cell migration, invasion, and epithelial-mesenchymal transition while promoting apoptosis. In vivo xenograft assay also illustrated that DGCR5 overexpression inhibited BCa growth. In the mechanism, we found that DGCR5 interacted with AT-rich interaction domain 1A (ARID1A), a chromatin remodeling protein, to promote P21 transcription. Knockdown of P21 could significantly rescue the suppressed proliferation, migration, and invasion of BCa cells by DGCR5 overexpression. In summary, our study demonstrated that DGCR5 transcriptionally promotes P21 expression to suppress BCa progression.

Conceptual frameworks of synthetic lethality in clear cell carcinoma of the ovary.

Targeting non-oncogenes may result in the selective death of cancer cells. Clear cell carcinoma of the ovary (CCC) may exhibit resistance against conventional chemotherapy and is associated with poor prognosis. The aim of the present report was to review synthetic lethality-based therapies for CCC. Previous English-language studies were reviewed to accumulate preclinical and clinical data on targeting synthetic lethal partners. Synthetic lethal interactions have a variety of types, involving components of a backup or parallel pathway with overlapping functions, components encoded by paralogous pairs, subunit components that form heteromeric complexes and components that are arranged in a single linear pathway. A set of candidate gene targets potentially resulting in synthetic lethality have been previously identified. HNF class homeobox, AT-rich interaction domain 1A, ATR serine/threonine kinase, ATM serine/threonine kinase, checkpoint kinase 1 and phosphatase and tensin homolog may be the key partner genes. A variety of loss of function genes in CCC are driver or passenger events and may function as synthetic lethal pairs under replication stress conditions. Further clinical studies will be required to investigate the safety and therapeutic effect of synthetic lethality pairs in CCC tumor types with replication stress.

ARID1B as a Potential Therapeutic Target for ARID1A-Mutant Ovarian Clear Cell Carcinoma.

AT-rich interactive domain 1A (ARID1A) and AT-rich interactive domain 1B (ARID1B) are subunits of the SWI/SNF chromatin complex. ARID1A is a tumor suppressor gene that is frequently mutated (46%) in ovarian clear cell carcinomas (OCCC). Loss of ARID1B in an ARID1A-deficient background eliminates the intact SWI/SNF complex, indicating that ARID1B is essential for the formation or stabilization of an intact SWI/SNF complex and, thus, the survival of ARID1A-mutant cancer cell lines. In this study, we investigated the clinicopathologic and prognostic relevance of ARID1B in OCCC by immunohistochemical analysis of 53 OCCC patient samples and loss-of-function experiments in OCCC cell lines. We also examined whether ARID1B could be a therapeutic target or prognostic biomarker in OCCC. siRNA-mediated knockdown of ARID1B in an ARID1A-mutant cell line significantly decreased cell growth, whereas concurrent depletion of both ARID1A and ARID1B was required to decrease wild type cell growth. In the immunohistochemical analyses, low ARID1B level was frequent in samples lacking ARID1A and was associated with shorter progression-free survival. This is the first report demonstrating that a low ARID1B level could be a marker of poor prognosis in OCCC. Moreover, the correlation between the loss of ARID1A immunoreactivity and reduced ARID1B levels indicates that ARID1B could be an attractive target for anti-cancer therapy.

The characteristics of ARID1A mutations in colorectal cancer.

3595Background: AT-rich interactive domain 1A (ARID1A) is a component of the SWI/SNF chromatin remodeling complex that regulates gene expression. Inactivating mutations of ARID1A have been reported...

Cancer panel analysis of circulating tumor cells in patients with breast cancer.

Liquid biopsy using circulating tumor cells (CTCs) is a noninvasive and repeatable procedure, and is therefore useful for molecular assays. However, the rarity of CTCs remains a challenge. To overcome this issue, our group developed a novel technology for the isolation of CTCs on the basis of cell size difference. The present study isolated CTCs from patients with breast cancer using this method, and then used these cells for cancer gene panel analysis. Blood samples from eight patients with breast cancer were collected, and CTCs were enriched using size-based filtration. Enriched CTCs were counted using immunofluorescent staining with an epithelial cell adhesion molecule (EpCAM) and CD45 antibodies. CTC genomic DNA was extracted, amplified, and screened for mutations in 400 genes using the Ion AmpliSeq Comprehensive Cancer Panel. White blood cells (WBCs) from the same patient served as a negative control, and mutations in CTCs and WBCs were compared. EpCAM+ cells were detected in seven out of eight patients, and the average number of EpCAM+ cells was 8.6. The average amount of amplified DNA was 32.7 µg, and the percentage of reads mapped to any targeted region relative to all reads mapped to the reference was 98.6%. The detection rate of CTC-specific mutations was 62.5%. The CTC-specific mutations were enhancer of zeste polycomb repressive complex 2 subunit, notch 1, AT-rich interaction domain 1A, serine/threonine kinase 11, fms related tyrosine kinase 3, MYCN proto-oncogene, bHLH transcription factor, APC, WNT signaling pathway regulator, and phosphatase and tensin homolog. The technique used by the present study was demonstrated to be effective at isolating CTCs at a sufficiently high purity for genomic analysis, and supported the use of comprehensive cancer panel analysis as a potential application for precision medicine.

Genetic analysis and phosphoinositide 3-kinase/protein kinase B signaling pathway status in ovarian endometrioid borderline tumor samples.

Ovarian endometrioid borderline tumors (EBTs) are extremely rare, and are thought to be precursors of endometrioid carcinoma, beginning as adenofibroma or endometriosis and progressing in a slow, stepwise manner. In endometrioid carcinomas, a high frequency of activating mutations in phosphatase and tensin homolog (PTEN), β-catenin or AT-rich interaction domain 1A (ARID1A) genes, and the activation of the phosphoinositide 3-kinase (PI3K)/protein kinase B (AKT) signaling pathway have been observed. However, the frequency of these alterations in EBTs and how they contribute to tumor progression remain unclear. To the best of our knowledge, this is the first study to assess the status of the PI3K/AKT signaling pathway in EBTs, in association with PTEN and ARID1A mutations. PTEN mutations were observed in EBTs and also in the area of endometriosis without atypia. However, the PI3K/AKT signaling pathway was revealed to be activated only in EBTs. The observations of the present study suggest that the PTEN mutation represents an early event in EBT tumorigenesis, while additional genetic alterations may be necessary to activate the PI3K/AKT signaling pathway and induce the development of the invasive carcinoma.

ARID1A deficiency promotes mutability and potentiates therapeutic antitumor immunity unleashed by immune checkpoint blockade.

ARID1A (the AT-rich interaction domain 1A, also known as BAF250a) is one of the most commonly mutated genes in cancer1,2. The majority of ARID1A mutations are inactivating mutations and lead to loss of ARID1A expression 3 , which makes ARID1A a poor therapeutic target. Therefore, it is of clinical importance to identify molecular consequences of ARID1A deficiency that create therapeutic vulnerabilities in ARID1A-mutant tumors. In a proteomic screen, we found that ARID1A interacts with mismatch repair (MMR) protein MSH2. ARID1A recruited MSH2 to chromatin during DNA replication and promoted MMR. Conversely, ARID1A inactivation compromised MMR and increased mutagenesis. ARID1A deficiency correlated with microsatellite instability genomic signature and a predominant C>T mutation pattern and increased mutation load across multiple human cancer types. Tumors formed by an ARID1A-deficient ovarian cancer cell line in syngeneic mice displayed increased mutation load, elevated numbers of tumor-infiltrating lymphocytes, and PD-L1 expression. Notably, treatment with anti-PD-L1 antibody reduced tumor burden and prolonged survival of mice bearing ARID1A-deficient but not ARID1A-wild-type ovarian tumors. Together, these results suggest ARID1A deficiency contributes to impaired MMR and mutator phenotype in cancer, and may cooperate with immune checkpoint blockade therapy.

ARID1A ablation leads to multiple drug resistance in ovarian cancer via transcriptional activation of MRP2

Multiple Drug Resistance (MDR) of ovarian cancer is a severe trouble for clinical treatment and always contributes to a bad prognosis. AT-rich interaction domain 1 A (ARID1A) has been recognized as a bona fide tumor suppressor gene in recent years, with the highest mutation rate in ovarian cancer. Previous study illustrated that ARID1A expression is negatively correlated with chemoresistance of ovarian cancer cases. However, the specific role of ARID1A in chemoresistance of ovarian cancer remains elusive. In this study, we showed that ARID1A knockdown in ovarian cancer cells significantly reduced their apoptosis rate and led to MDR, while ectopic expression of ARID1A showed opposite effects. ARID1A depletion transcriptionally activates the expression of multidrug resistance-associated protein 2 (MRP2) following chromatin remodeling. Furthermore, IHC analysis of ovarian cancer samples confirmed that ARID1A expression was strong negatively correlated with MRP2 expression. Both ARID1A and MRP2 expression levels are correlated with sensitivity to platinum. Collectively, our results illustrated that ARID1A loss in ovarian cancer leads to MDR through upregulation of MRP2, providing an opportunity to overcome the ARID1A loss induced chemoresistance of ovarian cancer by targeting MRP2.

Mitochondrial tumor suppressor 1 is a target of AT-rich interactive domain 1A and progesterone receptor in the murine uterus.

ObjectiveProgesterone receptor (PGR) and AT-rich interactive domain 1A (ARID1A) have important roles in the establishment and maintenance of pregnancy in the uterus. In present studies, we examined the expression of mitochondrial tumor suppressor 1 (MTUS1) in the murine uterus during early pregnancy as well as in response to ovarian steroid hormone treatment.MethodsWe performed quantitative reverse transcription polymerase chain reaction and immunohistochemistry analysis to investigate the regulation of MTUS1 by ARID1A and determined expression patterns of MTUS1 in the uterus during early pregnancy.ResultsThe expression of MTUS1 was detected on day 0.5 of gestation (GD 0.5) and then gradually increased until GD 3.5 in the luminal and glandular epithelium. However, the expression of MTUS1 was significantly reduced in the uterine epithelial cells of Pgrcre/+Arid1af/f and Pgr knockout (PRKO) mice at GD 3.5. Furthermore, MTUS1 expression was remarkably induced after P4 treatment in the luminal and glandular epithelium of the wild-type mice. However, the induction of MTUS1 expression was not detected in uteri of Pgrcre/+Arid1af/f or PRKO mice treated with P4.ConclusionThese results suggest that MTUS1 is a novel target gene by ARID1A and PGR in the uterine epithelial cells.

An epigenetic switch on ARID1A chromatin remodeler by alpha‐oxoglutarate activates the antiproliferative axis in interstitial cystitis

Interstitial cystitis (IC) is a chronic urinary tract disease that is characterized by unpleasant sensations, such as chronic pelvic pain and various other symptoms, in the absence of infection or other identifiable causes. We previously performed comprehensive metabolomics profiling of urine in IC patients using nuclear magnetic resonance and gas-chromatography/mass spectrometry and found that urinary α-oxoglutarate was significantly elevated. α-oxoglutarate (α-OG), the tricarboxylic acid (TCA) cycle intermediate, reportedly functions to suppress the proliferation of normal human bladder epithelial cells. Here, we identified AT-rich interactive domain 1A (ARID1A), a key chromatin remodeler, as being hypomethylated and upregulated by 2-oxoglutarate treatment. This was done through EPIC DNA methylation profiling and subsequent biochemical approaches, including quantitative RT-PCR and western blot analyses. Furthermore, we found that α-oxoglutarate almost completely suppresses ten-eleven translation (TET) activity, but does not affect DNA methyltransferase (DNMT) activity. DNMT inhibition in our IC rat models did not limit IC-associated symptoms or cytokine production. Altogether, our studies reveal the potential role of α-OG in epigenetic remodeling through its effects on AR1DA and TET in the bladder, which could provide a promising therapeutic strategy for IC treatment. Support or Funding Information The authors acknowledge support from National Institutes of Health grants (1U01DK103260, 1R01DK100974, U24 DK097154, NIH NCATS UCLA CTSI UL1TR000124), Department of Defense grants (W81XWH-15-1-0415), Centers for Disease Controls and Prevention (1U01DP006079), IMAGINE NO IC Research Grant, the Steven Spielberg Discovery Fund in Prostate Cancer Research Career Development Award, the U.S.-Egypt Science and Technology Development Fund by the National Academies of Sciences, Engineering, and Medicine (to J.K.). J.K. is former recipient of Interstitial Cystitis Association Pilot Grant, a Fishbein Family IC Research Grant, New York Academy of Medicine, and Boston Children's Hospital Faculty Development. The funders had no role in the design, data collection and analysis, decision to publish or preparation of the manuscript. This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.

Alpha-oxoglutarate inhibits the proliferation of immortalized normal bladder epithelial cells via an epigenetic switch involving ARID1A

Interstitial cystitis (IC) is a chronic urinary tract disease that is characterized by unpleasant sensations, such as persistent pelvic pain, in the absence of infection or other identifiable causes. We previously performed comprehensive metabolomics profiling of urine samples from IC patients using nuclear magnetic resonance and gas-chromatography/mass spectrometry and found that urinary α-oxoglutarate (α-OG), was significantly elevated. α-OG, a tricarboxylic acid (TCA) cycle intermediate, reportedly functions to suppress the proliferation of immortalized normal human bladder epithelial cells. Here, we identified AT-rich interactive domain 1 A (ARID1A), a key chromatin remodeler, as being hypomethylated and upregulated by α-OG treatment. This was done through EPIC DNA methylation profiling and subsequent biochemical approaches, including quantitative RT-PCR and western blot analyses. Furthermore, we found that α-OG almost completely suppresses ten-eleven translocation (TET) activity, but does not affect DNA methyltransferase (DNMT) activity. Altogether, our studies reveal the potential role of α-OG in epigenetic remodeling through its effects on ARID1A and TET expression in the bladder. This may provide a new possible therapeutic strategy in treating IC.

Loss of Chromatin-Remodeling Proteins and/or CDKN2A Associates With Metastasis of Pancreatic Neuroendocrine Tumors and Reduced Patient Survival Times

Despite prognostic grading and staging systems, it is a challenge to predict outcomes for patients with pancreatic neuroendocrine tumors (PanNETs). Sequencing studies of PanNETs have identified alterations in death domain-associated protein (DAXX) and alpha-thalassemia/mental retardation X-linked chromatin remodeler (ATRX). In tumors, mutations in DAXX or ATRX and corresponding loss of protein expression correlate with shorter times of disease-free survival and disease-specific survival of patients. However, DAXX or ATRX proteins were lost in only 50% of distant metastases analyzed. We performed whole-exome sequencing analyses of 20 distant metastases from 20 patients with a single nonsyndrome, nonfunctional PanNET. We found distant metastases contained alterations in multiple endocrine neoplasia type 1 (MEN1) (n= 8), ATRX (n= 5), DAXX (n= 5), TSC2 (n= 3), and DEP domain containing 5 (DEPDC5) (n= 3). We found copy number loss of cyclin dependent kinase inhibitor 2A (CDKN2A) in 15 metastases (75%) and alterations in genes that regulate chromatin remodeling, including set domain containing 2 (SETD2) (n= 4), AT-rich interaction domain 1A (ARID1A) (n= 2), chromodomain helicase DNA binding protein 8 (CHD8) (n= 2), and DNA methyl transferase 1 (DNMT1) (n= 2). In a separate analysis of 347 primary PanNETs, we found loss or deletion of DAXX and ATRX, disruption of SETD2 function (based on loss of H3 lysine 36 trimethylation), loss of ARID1A expression or deletions in CDKN2A in 81% of primary PanNETs with distant metastases. Among patients with loss or deletion of at least 1 of these proteins or genes, 39% survived disease-free for 5 years and 44% had disease-specific survival times of 10 years. Among patients without any of these alterations, 98% survived disease-free for 5 years and 95% had disease-specific survival times of 10 years. Therefore, primary PanNETs with loss of DAXX, ATRX, H3 lysine 36 trimethylation, ARID1A, and/or CDKN2A associate with shorter survival times of patients. Our findings indicate that alterations in chromatin-remodeling genes and CDKN2A contribute to metastasis of PanNETs.

Prevalence of common polymorphisms of AT-rich interaction domain 1A and endothelial nitric oxide synthase in patients with endometriosis compared to control group

Introduction: Endometriosis is a common gynecologic disorder defined as ectopic presence of endometrial tissue in extrauterine sites. Endometriosis is associated with infertility and risk of malignancy. Identification of genetic factors responsible for development and malignant transformation of endometriosis can improve therapeutic approaches. In this study, we investigated the association of AT-rich interaction domain 1A ( ARID1A) and endothelial nitric oxide synthase ( eNOS) polymorphisms with endometriosis and staging of the disease. Methods: A total of 100 women with laparoscopy-confirmed diagnosis of endometriosis were included and compared with 100 women without endometriosis as the control group. Genotypes of patients regarding Gln920Ter polymorphism of ARID1A gene and Glu298Asp polymorphism of eNOS gene were determined by polymerase chain reaction techniques on blood samples from the study population. The prevalence of each genotype in endometriosis patients was compared with healthy controls using the chi-square test. Results: Significantly higher prevalence of non-CC genotype for ARID1A Gln920Ter polymorphism and non-GG genotype for G894T polymorphism of the eNOS gene was detected in the endometriosis group. There was no significant relationship between these polymorphisms and staging of endometriosis. Discussion: Significant variation of prevalence of Gln920Ter polymorphism of the ARID1A gene and Glu298Asp polymorphism of the eNOS gene among the two groups can indicate a causative effect of these genetic alterations on the development of endometriosis.

High‐level expression of ARID1A predicts a favourable outcome in triple‐negative breast cancer patients receiving paclitaxel‐based chemotherapy

Paclitaxel‐based chemotherapy is a common strategy to treat patients with triple‐negative breast cancer (TNBC). As paclitaxel resistance is still a clinical issue in treating TNBCs, identifying molecular markers for predicting pathologic responses to paclitaxel treatment is thus urgently needed. Here, we report that an AT‐rich interaction domain 1A (ARID1A) transcript is up‐regulated in paclitaxel‐sensitive TNBC cells but down‐regulated in paclitaxel‐resistant cells upon paclitaxel treatment. Moreover, ARID1A expression was negatively correlated with the IC 50 concentration of paclitaxel in the tested TNBC cell lines. Kaplan‐Meier analyses revealed that ARID1A down‐regulation was related to a poorer response to paclitaxel‐based chemotherapy in patients with TNBCs as measured by the recurrence‐free survival probability. The pharmaceutical inhibition with p38MAPK‐specific inhibitor SCIO‐469 revealed that p38MAPK‐related signalling axis regulates ARID1A expression and thereby modulates paclitaxel sensitivity in TNBC cells. These findings suggest that ARID1A could be used as a prognostic factor to estimate the pathological complete response for TNBC patients who decide to receive paclitaxel‐based chemotherapy.

Loss of ARID1A Expression Correlates With Tumor Differentiation and Tumor Progression Stage in Pancreatic Ductal Adenocarcinoma.

Mutations in the AT-rich interactive domain 1A gene, which encodes a subunit of the Switch/Sucrose nonfermentable chromatin remodeling complex, can result in loss of protein expression and are associated with different cancers. Here, we used immunohistochemistry to investigate the significance of AT-rich interactive domain 1A loss in 73 pancreatic ductal adenocarcinoma cases with paired paracancerous normal pancreatic tissues. The relationship between levels of the AT-rich interactive domain 1A protein product, BAF250a, and clinicopathological parameters in the 73 pancreatic cancer specimens was also analyzed. We found that the expression of AT-rich interactive domain 1A in normal pancreatic tissue was higher than that in tumor tissue. Loss of AT-rich interactive domain 1A expression in pancreatic tumors was associated with tumor differentiation (P = .002) and tumor stage (P = .048). Meanwhile, BAF250a protein levels were not related to lymph node metastasis, distant metastasis, sex, or age and were not associated with survival. Transfection of the pancreatic cancer cell lines AsPC-1 and PANC-1 with small-interfering RNA specific for AT-rich interactive domain 1A resulted in elevated messenger RNA and protein expression levels of B-cell lymphoma-2 (Bcl-2), CyclinD1, and Kirsten rat sarcoma viral oncogene (KRAS). The AT-rich interactive domain 1A expression level in the cells was increased following microRNA-31 (miR-31) inhibitor transfection. Our data provide additional evidence that AT-rich interactive domain 1A might function as a tumor suppressor gene in pancreatic carcinogenesis.

Gastritis-Infection-Cancer Sequence of Epstein-Barr Virus-Associated Gastric Cancer.

Epstein-Barr virus-associated gastric cancer (EBVaGC) is a representative EBV-infected epithelial neoplasm, which is now included as one of the four subtypes of The Cancer Genome Atlas molecular classification of gastric cancer. In this review, we portray a gastritis-infection-cancer sequence of EBVaGC. This virus-associated type of gastric cancer demonstrates clonal growth of EBV-infected epithelial cells within the mucosa of atrophic gastritis. Its core molecular abnormality is the EBV-specific hyper-epigenotype of CpG island promoter methylation, which induces silencing of tumor suppressor genes. This is due to the infection-induced disruption of the balance between DNA methylation and DNA demethylation activities. Abnormalities in the host cell genome, including phosphatidylinositol-4,5-biphosphate 3-kinase catalytic subunit α (PIK3CA), AT-rich interaction domain 1A (ARID1A), and programmed death-ligand 1 (PD-L1), are associated with the development and progression of EBVaGC. Furthermore, posttranscriptional modulation affects the transformation processes of EBV-infected cells, such as epithelial mesenchymal transition and anti-apoptosis, via cellular and viral microRNAs (miRNAs). Once established, cancer cells of EBVaGC remodel their microenvironment, at least partly, via the delivery of exosomes containing cellular and viral miRNAs. After exosomes are incorporated, these molecules change the functions of stromal cells, tuning the microenvironment for EBVaGC. During this series of events, EBV hijacks and uses cellular machineries, such as DNA methylation and the miRNA delivery system. This portrait of gastritis-infection-cancer sequences highlights the survival strategies of EBV in the stomach epithelial cells and may be useful for the integration of therapeutic modalities against EBV-driven gastric cancer.