Background
AT-rich interactive domain 1A (
ARID1A
) is a tumor suppressor gene that is frequently mutated in gastric cancer (GC). Although
ARID1A
mutations are not a druggable target for conventional ...treatments, novel therapeutic strategies based on a synthetic lethal approach are effective for ARID1A-deficient cancers. The histone methyltransferase EZH2 acts in a synthetic lethal manner in
ARID1A
-mutated ovarian cancer, although its role in GC remains unknown.
Methods
The selective sensitivity of the EZH2 inhibitors for ARID1A-deficient GC cells was evaluated using cell viability and colony formation assays. The expression of PI3K/AKT signaling genes were investigated using TCGA’s cBioPortal database to determine whether the homeostasis between ARID1A and EZH2 is related to cell proliferation and survival via the PI3K/AKT signaling pathway. We also evaluated the phosphorylation of PI3K/AKT signaling proteins in
ARID1A
knock downed
ARID1A
-WT GC cells.
Results
EZH2 inhibitors decreased the viability of ARID1A-deficient cells in a dose-dependent manner and demonstrated the selective sensitivity to ARID1A-deficient cells in vitro experiment system. Bioinformatics approach revealed that the PI3K/AKT signaling was tended to be activated in ARID1A-deficient GC enhancing cell viability and, furthermore, down-regulation of EZH2 in ARID1A-deficient GC was related to normalization of PI3K/AKT signaling pathway. The cell experiment revealed that phosphorylated AKT was upregulated in ARID1A-deficent GC cells.
Conclusions
The present findings provide a rationale for the selective sensitivity of EZH2 inhibitors against ARID1A-deficient GC and suggest the potential efficacy of targeted therapy using EZH2 inhibitors in this patient population.
Immunotherapy against the interaction between programmed cell death 1/programmed cell death ligand 1 (PD-L1) has emerged as a promising strategy for colorectal cancer with mismatch repair deficiency ...(dMMR) or microsatellite instability-high (MSI-H). The study aimed to identify miRNAs that posttranscriptionally control PD-L1 expression on tumor cells and also regulate immune evasion. A comprehensive miRNA screening using The Cancer Genome Atlas (TCGA) dataset (
= 260) combined with eight different miRNA target prediction programs resulted in the identification of a tumor suppressive miRNA, miR-148a-3p, as a potential negative regulator of PD-L1 expression, particularly in dMMR/MSI-H colorectal cancer. Using multiple cohorts of colorectal cancer, including TCGA data, a microarray dataset (
= 148), and formalin-fixed, paraffin-embedded samples (
= 395), we found that the expression of miR-148a-3p was decreased in dMMR/MSI-H tumors, correlating inversely with PD-L1 levels. We demonstrate that miR-148a-3p directly binds to the 3'-untranslated region of PD-L1, thereby reducing whole-cell and cell surface PD-L1 levels in HCT116 and SW837 cell lines. Overexpression of miR-148a-3p repressed IFNγ-induced PD-L1 expression on tumor cells and consequently diminished T-cell apoptosis in a coculture model of IL2-activated T cells and IFNγ-treated tumor cells. In conclusion, our data support a regulatory mechanism of PD-L1 expression on tumor cells and immune suppression via miR-148a-3p downregulation in colorectal cancer. IMPLICATIONS: This study provides novel evidence that miR-148a-3p negatively regulates tumor cell PD-L1 expression and decreased levels of miR-148a-3p contributes to the immunosuppressive tumor microenvironment.
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.
Background
Several articles have recently reported that certain colon microbiota can improve the efficacy of cancer immunotherapy. To develop new treatment strategies, including immunotherapy for ...colorectal cancer (CRC), we evaluated the correlations between subpopulations of tumor-infiltrating immune cells (TIICs) and intestinal microbiota in CRC.
Methods
Fresh surgically resected specimens, formalin-fixed paraffin-embedded whole tissue samples, and stool samples were collected. TIICs including Tregs, Th17 cells and tumor-associated macrophages (TAMs) in the surgically resected specimens were analyzed using flow cytometry. FOXp3, CD8, CD163, and phosphorylated-STAT1-positive TIICs in the whole tissue samples were analyzed using IHC, and intestinal microbiota in the stool samples was analyzed using 16S metagenome sequencing. TIICs subpopulations in the normal mucosa and tumor samples were evaluated, and the correlations between the TIIC subpopulations and intestinal microbiota were analyzed.
Results
FOXp3
low
CD45RA
+
Tregs were significantly reduced (
p
= 0.02), FOXp3
low
CD45RA
−
Tregs were significantly increased (
p
= 0.006), and M1 TAMs were significantly reduced in the tumor samples (
p
= 0.03).
Bacteroides
(phylum
Bacteroidetes
) and
Faecalibacterium
(phylum
Firmicutes
) were increased in the patients with high numbers of Tregs and clearly high distribution of FOXp3
high
CD45RA
−
Tregs, which are the effector Tregs.
Faecalibacterium, Ruminococcaceae, Eubacterium
(phylum
Firmicutes
), and
Bacteroides
were increased in patients with a high distribution of M1 TAMs.
Conclusions
The findings of the present study indicate that immune responses to tumors are suppressed in the tumor microenvironment of CRC depending on the increment of Tregs and the reduction of M1 TAMs and that intestinal microbiota might be involved in immunosuppression.
The BRAF
mutation is the most frequent genetic abnormality in adult papillary thyroid carcinomas (PTCs). On the other hand, various chromosomal rearrangements are more prevalent in childhood and ...adolescent PTCs. The aim of the present study was to identify novel rearrangements in PTCs from young patients.
Among 63 postoperative specimens of childhood and adolescent PTCs, which had been discovered by the thyroid ultrasound screening program in Fukushima, nine samples without prevalent known oncogenes, BRAF
, RAS, RET/PTC1, RET/PTC3, and ETV6/NTRK3, were analyzed in the current study by quantitative real-time reverse transcription polymerase chain reaction to screen for novel fusion genes by comparing transcript expression between extracellular and kinase domains of ALK, NTRK1, NTRK3, and RET.
Of the above nine samples, five samples were suspected to harbor a fusion, and using subsequent 5' rapid amplification of cDNA end (RACE), two already reported fusion oncogenes, STRN/ALK and TPR/NTRK1, and three novel fusions, SQSTM1/NTRK3, AFAP1L2/RET, and PPFIBP2/RET, were identified. Functional analyses of these three chimeric genes were performed, and their transforming abilities were confirmed through the activation of mitogen-activated protein kinase (MAPK).
Three novel fusion oncogenes have been identified in young PTC patients in Fukushima, suggesting that rare fusions may be present among the cases negative for known oncogenes in this age group and that such rearrangements can play a significant role in thyroid carcinogenesis.
The expression of fucosyltransferase 8, an enzyme responsible for core fucosylation encoded by FUT8, influences tumor biology and correlates with patient prognosis in several solid cancers. We ...hypothesized that p53 alteration modifies prognostic associations of FUT8 expression in colorectal cancer (CRC), since FUT8 has recently been identified as a direct transcriptional target of wild-type p53. Utilizing multiple datasets of microarray and RNA sequence of CRC, FUT8 mRNA was found to be highly expressed in wild-type p53 tumors (n = 382) compared to those of mutant p53 (n = 437). Prognostic values of FUT8 expression in conjunction with the p53 status for disease-free survival (DFS) were analyzed using two independent cohorts of stage II and III CRC after curative surgery, including the immunohistochemistry (IHC) cohort (n = 123) and the microarray cohort (n = 357). In both cohorts, neither FUT8 expression nor the p53 status was associated with DFS. Strikingly, positive expression of FUT8 protein was significantly associated with better DFS only in tumors with negative p53, while it had no prognostic impact in tumors with positive p53 in the IHC cohort. Although not statistically significant, a similar prognostic trend was observed in the microarray cohort when patients were stratified by the p53 status. Our results suggest that the prognostic values of FUT8 expression on DFS may be modified by the p53 status, and the expression of FUT8 protein can be a prognostic biomarker for patients with stage II and III CRC.
Abstract
Adjuvant chemotherapy is considered for patients with stage II colorectal cancer (CRC) characterized by poor prognostic clinicopathological features; however, current stratification ...algorithms remain inadequate for identifying high-risk patients. To develop prognostic assays, we conducted a step-wise screening and validation strategy using nine cohorts of stage II patients based on multiple platforms, including microarray, RNA-sequencing (RNA-seq) and immunohistochemistry (IHC) on formalin-fixed paraffin-embedded (FFPE) tissues. Four microarray datasets (total n = 458) were used as the discovery set to screen for single genes associated with postoperative recurrence. Prognostic values of candidate genes were evaluated in three independent microarray/RNA-seq validation cohorts (n = 89, n = 93 and n = 183, respectively), and then IHC for KRT17 was conducted in two independent FFPE series (n = 110 and n = 44, respectively). We found that high levels of KRT17 transcript expression were significantly associated with poor relapse-free survival (RFS) not only in the discovery set, but also in three validation cohorts, and its prognostic impact was independent of conventional factors by multivariate analyses. Positive staining of KRT17 protein was significantly associated with poor RFS in two independent FFPE cohorts. KRT17 protein expression had independent prognostic impact on RFS in a multivariate model adjusted for conventional variables, including high-risk clinicopathological features. In conclusion, using nine independent cohorts consisting of 997 stage II patients, we identified and validated the expression of KRT17 transcript and KRT17 protein as a robust prognostic biomarker that can discriminate postoperative stage II patients who are at high probability of disease recurrence, providing additional prognostic stratification beyond the currently available high-risk factors.
Esophageal squamous cell carcinoma (ESCC) is an aggressive tumor, and it is urgently needed to develop novel therapeutic strategies including immunotherapy. In this study, we investigated the ...upregulation of the programmed death ligand 1 (PD‐L1) due to epithelial‐mesenchymal transition (EMT) in ESCC using an in vitro treatment system with the EMT inducer, glycogen synthase kinase (GSK)‐3 inhibitor, and we also analyzed the correlation of EMT and PD‐L1 expression in the clinical tumor samples of both tissue microarray (TMA) samples (n = 177) and whole tissue samples (n = 21). As a result, the inhibition of GSK‐3β induces EMT phenotype with upregulated vimentin and downregulated E‐cadherin as well as increased Snail and Zinc finger E box‐binding homeobox (ZEB)‐1 gene expression. Simultaneously, we showed that EMT‐converted ESCC indicated the upregulation of PD‐L1 at both protein (total and surface) and mRNA levels. Of importance, we showed that EMT‐converted tumor cells have a capability to induce T‐cell apoptosis to a greater extent in comparison to original epithelial type tumor cells. Furthermore, the immunohistochemical stains of ESCC showed that PD‐L1 expression on tumor cells was positively correlated with EMT status in TMA samples (P = .0004) and whole tissue samples (P = .0029). In conclusion, our in vitro and in vivo study clearly demonstrated that PD‐L1 expression was upregulated in mesenchymal type tumors of ESCC. These findings provide a strong rationale for the clinical use of anti‐PD‐1/anti‐PD‐L1 monoclonal antibodies for advanced ESCC patients.
We proved that the epithelial‐mesenchymal transition (EMT)‐converted cancer cells showed the upregulation of the surface expression of programmed death ligand 1 (PD‐L1) and induced the apoptosis of T cells through the PD‐1/PD‐L1 pathway. Furthermore, we showed that PD‐L1 expression on tumor cells was positively correlated with EMT status in surgically resected specimens of esophageal squamous cell carcinoma (ESCC) by the immunohistochemistry. These findings provide a strong rationale for the clinical use of anti‐PD‐1/anti‐PD‐L1 monoclonal antibodies for advanced ESCC patients.
Gastric and colorectal cancers are leading causes of death worldwide. Although a relationship between inflammation and the innate immunity in cancer-bearing hosts is widely accepted, the precise cell ...mechanisms mediating this relationship have not been elucidated. The aim of this study was to investigate the status of systemic inflammation, immune suppression, malnutrition, and prognosis associated with interleukin (IL)-17 and vascular endothelial growth factor (VEGF) in patients with gastric and colorectal cancers.The production of IL-17 and the serum levels of VEGF in patients with gastric and colorectal cancers were up-regulated in advanced stages of the diseases, which were positively correlated with the levels of myeloid-derived suppressor cells, the neutrophil-to-lymphocyte ratio, and C-reactive protein, while both were inversely correlated with IL-12 production, stimulation index, and nutritional markers including prealbumin and retinol binding protein. Overall survival of patients with stage III and IV gastric or colorectal cancer was significantly worse for patients with high IL-17 production or high VEGF levels than for those with low IL-17 production or low VEGF levels. The observations in the present study suggest that IL-17 and VEGF are closely associated with disease progression, and may serve as useful markers of the immune suppression, malnutrition, and prognosis in patients with gastric and colorectal cancers.
We aimed to discover glycosyltransferase gene (glycogene)-derived molecular subtypes of colorectal cancer associated with patient outcomes.
Transcriptomic and epigenomic datasets of nontumor, ...precancerous, cancerous tissues, and cell lines with somatic mutations, mismatch repair status, clinicopathologic and survival information were assembled (
= 4,223) and glycogene profiles were analyzed. IHC for a glycogene, GALNT6, was conducted in adenoma and carcinoma specimens (
= 403). The functional role and cell surface glycan profiles were further investigated by
loss-of-function assays and lectin microarray analysis.
We initially developed and validated a 15-glycogene signature that can identify a poor-prognostic subtype, which closely related to deficient mismatch repair (dMMR) and
downregulation. The association of decreased
with dMMR was confirmed in multiple datasets of tumors and cell lines, and was further recapitulated by IHC, where approximately 15% tumors exhibited loss of GALNT6 protein. GALNT6 mRNA and protein was expressed in premalignant/preinvasive lesions but was subsequently downregulated in a subset of carcinomas, possibly through epigenetic silencing. Decreased GALNT6 was independently associated with poor prognosis in the IHC cohort and an additional microarray meta-cohort, by multivariate analyses, and its discriminative power of survival was particularly remarkable in stage III patients.
silencing in SW480 cells promoted invasion, migration, chemoresistance, and increased cell surface expression of a cancer-associated truncated O-glycan, Tn-antigen.
The 15-glycogene signature and the expression levels of GALNT6 mRNA and protein each serve as a novel prognostic biomarker, highlighting the role of dysregulated glycogenes in cancer-associated glycan synthesis and poor prognosis.
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