ASAP1 activates the IQGAP1/CDC42 pathway to promote tumor progression and chemotherapy resistance in gastric cancer.

Abnormal expression and remodeling of cytoskeletal regulatory proteins are important mechanisms for tumor development and chemotherapy resistance. This study systematically analyzed the relationship between differential expression of cytoskeleton genes and prognosis in gastric cancer (GC). We found the Arf GTP-activating protein ASAP1 plays a key role in cytoskeletal remodeling and prognosis in GC patients. Here we analyzed the expression level of ASAP1 in tissue microarrays carrying 564 GC tissues by immunohistochemistry. The results showed that ASAP1 expression was upregulated in GC cells and can be served as a predictor of poor prognosis. Moreover, ASAP1 promoted the proliferation, migration, and invasion of GC cells both in vitro and in vivo. We also demonstrated that ASAP1 inhibited the ubiquitin-mediated degradation of IQGAP1 and thus enhanced the activity of CDC42. The activated CDC42 upregulated the EGFR-MAPK pathway, thereby promoting the resistance to chemotherapy in GC. Taken together, our results revealed a novel mechanism by which ASAP1 acts in the progression and chemotherapy resistance in GC. This may provide an additional treatment option for patients with GC.

Emerging roles of long noncoding RNAs in chemoresistance of pancreatic cancer.

Pancreatic cancer is one of the most common causes of cancer death in the world due to the lack of early symptoms, metastasis occurrence and chemoresistance. Therefore, early diagnosis by detection of biomarkers, blockade of metastasis, and overcoming chemoresistance are the effective strategies to improve the survival of pancreatic cancer patients. Accumulating evidence has revealed that long noncoding RNA (lncRNA) and circular RNAs (circRNAs) play essential roles in modulating chemosensitivity in pancreatic cancer. In this review article, we will summarize the role of lncRNAs in drug resistance of pancreatic cancer cells, including HOTTIP, HOTAIR, PVT1, linc-ROR, GAS5, UCA1, DYNC2H1-4, MEG3, TUG1, HOST2, HCP5, SLC7A11-AS1 and CASC2. We also highlight the function of circRNAs, such as circHIPK3 and circ_0000284, in regulation of drug sensitivity of pancreatic cancer cells. Moreover, we describe a number of compounds, including curcumin, genistein, resveratrol, quercetin, and salinomycin, which may modulate the expression of lncRNAs and enhance chemosensitivity in pancreatic cancers. Therefore, targeting specific lncRNAs and cicrRNAs could contribute to reverse chemoresistance of pancreatic cancer cells. We hope this review might stimulate the studies of lncRNAs and cicrRNAs, and develop the new therapeutic strategy via modulating these noncoding RNAs to promote chemosensitivity of pancreatic cancer cells.

The Human Cytomegalovirus US31 Gene Predicts Favorable Survival and Regulates the Tumor Microenvironment in Gastric Cancer.

Human cytomegalovirus (HCMV) is an oncogenic virus associated with tumorigenesis. Our previous study revealed that the HCMV US31 gene interacted with NF-κB2 and mediated inflammation through macrophages. However, there are few reports on the role of US31 in gastric cancer (GC). The aim of this study was to investigate the expression of the US31 gene in GC tissue and assess its role in the occurrence and development of GC. US31 expression in 573 cancer tissues was analyzed using immunohistochemistry. Results showed that US31 was significantly associated with tumor size (P = 0.005) and distant metastasis (P < 0.001). Higher US31 expression indicated better overall survival in GC patients. Overexpression of US31 significantly inhibited the proliferation, migration, and invasion of GC cells in vitro (P < 0.05). Furthermore, expression levels of CD4, CD66b, and CD166 were positively correlated with US31, suggesting that it was involved in regulating the tumor immune microenvironment of GC. RNA sequencing, along with quantitative real-time polymerase chain reaction, confirmed that the expression of US31 promoted immune activation and secretion of inflammatory cytokines. Overall, US31 inhibited the malignant phenotype and regulated tumor immune cell infiltration in GC; these results suggest that US31 could be a potential prognostic factor for GC and may open the door for a new immunotherapy strategy.

Patients with Helicobacter pylori-positive gastric cancer with human cytomegalovirus infection have a low tendency of advanced lymphatic metastasis in a Chinese population.

Recognized as a group I carcinogen for gastric cancer (GC) and a factor involved in the development of GC, Helicobacter pylori serves a major part in GC research. However, most studies have focused on H. pylori itself, ignoring the complicated pathogenic microbiological environment of GC and neglecting the synergistic or antagonistic effects of H. pylori with other pathogenic microorganisms. Increasing evidence has revealed that the human cytomegalovirus (HCMV) is present in several types of tumors and serves an important role in the neoplastic process of certain human malignant tumors, including GC. The aim of the present study was to explore the role of HCMV and H. pylori co-infection in GC. HCMV and H. pylori infection was analyzed in paired gastric tumor and peri-tumoral tissues from 134 (98 male and 36 female) patients using PCR. The results revealed that a total of 74 (55.2%) patients had H. pylori infection, 58 patients (43.3%) had HCMV infection, and 34 (25.4%) patients had both HCMV and H. pylori infection. Univariate and multivariate analyses demonstrated that H. pylori infection was independently associated with advanced lymphatic metastasis [P=0.007; odds ratio (OR)=3.51]. Furthermore, compared with HCMV-/H. pylori -, neither HCMV+/H. pylori - nor HCMV+/H. pylori + were associated with metastasis, but HCMV-/H. pylori + co-infection status was an independent risk factor for advanced lymphatic metastasis (P=0.005; OR=6.00). In conclusion, GC co-infected with HCMV and H. pylori exhibited a low tendency of lymph node metastasis. HCMV may interact with H. pylori to inhibit the process of lymphatic metastasis, and the mechanism requires further investigation.

Opposing biological functions of the cytoplasm and nucleus DAXX modified by SUMO-2/3 in gastric cancer.

Death domain-associated protein (DAXX) is a complex biological multifunctional protein and is involved in the tumorigenesis and progression of multiple cancers. The accumulation of DAXX in the nucleus is a common phenomenon in tumor cells. However, altering the subcellular localizations of DAXX results in different biological functions, and we also found that its nuclear/cytoplasmic ratio (NCR) was associated with poor prognosis in gastric cancer (GC). In this study, we investigated the effect of cytoplasmic and nuclear DAXX (cDAXX and nDAXX) in GC and the underlying mechanisms. Immunohistochemical detection performed in 323 GC tissues reveled that cDAXX was associated with a better survival, while high nDAXX expression suggested a poorer prognosis outcome. Upregulation of DAXX in the cytoplasm inhibited cell proliferation and promoted apoptosis, whereas downregulation of DAXX in the nucleus displayed opposite effects. Moreover, Transwell assays revealed that DAXX enhanced GC cell migration and invasion. Analysis from the Gene Expression Profile Interactive Analysis (GEPIA) database showed that the expression of DAXX was significantly associated with SUMO-2/3 in GC tissues. Co-immunoprecipitation combined with immunofluorescence analysis indicated that DAXX interacted directly with SUMO-2/3. Subsequently, down-regulating the expression of SUMO-2/3 resulted in altered subcellular localization of DAXX. Bioinformatics analysis showed that RanBP2 may act as SUMO E3 ligase to promote nuclear-plasma transport via combining with RanGAP1. Taken together, our results indicated that DAXX plays opposing roles in GC and suggest a new model whereby cDAXX, nDAXX, and SUMO-2/3 form a molecular network that regulates the subcellular localization of DAXX and thereby modulates its opposing biological effects. Thus, our findings provide a foundation for future studies of DAXX as a novel therapeutic target for patients with GC.

Overexpression of the human cytomegalovirus UL111A is correlated with favorable survival of patients with gastric cancer and changes T-cell infiltration and suppresses carcinogenesis.

PURPOSE: We previously found that human cytomegalovirus (HCMV) infection is associated with gastric cancer (GC) development. UL111A plays a role during HCMV productive or latent infection. However, UL111A expression profiles in GC tissues and their relationship with this disease are unknown. METHODS: PCR and nested RT-PCR were performed to verify UL111A expression in 71 GC tissues and its transcripts in 16 UL111A-positive GC samples. UL111A expression levels in GC patients were evaluated by immunohistochemistry on a tissue microarray for 620 GC patients. The correlations among UL111A expression levels, clinicopathological characteristics, and prognosis were analyzed. Further, the effects of overexpression of latency-associated viral interleukin-10 (LAcmvIL-10) and cmvIL-10 on GC cell proliferation, colony formation, migration, and invasion were assessed. RESULTS: The UL111A detection rate in GC tissues was 32.4% (23/71) and that of its mRNA expression was 68.75% (11/16). High expression of UL111A was also related to better overall and disease-free survival in GC patients. GC patients with TNM II/III stage expressing higher UL111A levels might benefit from adjuvant chemotherapy (ACT) after surgery. Moreover, high UL111A expression was also associated with increased CD4+ , CD8+ T-lymphocyte and Foxp3+ T-cell infiltration. In vitro assays further demonstrated that LAcmvIL-10 and cmvIL-10 overexpression inhibits GC cell line proliferation, colony formation, migration, and invasion. CONCLUSIONS: High UL111A expression changes the number of infiltrating T cells and is associated with favorable survival. Therefore, UL111A could be used as an independent prognostic biomarker and might be a potential therapeutic target for GC.

CD2AP inhibits metastasis in gastric cancer by promoting cellular adhesion and cytoskeleton assembly.

Diffuse gastric cancer (DGC) is a lethal malignancy lacking effective systemic therapy. Among the most provocative recent results in DGC has been that the alter of the cellular cytoskeleton and intercellular adhesion. CD2-associated protein (CD2AP) is one of the critical proteins regulating cytoskeleton assembly and intercellular adhesion. However, no study has investigated the expression and biological significance of CD2AP in gastric cancer (GC) to date. Therefore, the aim of our study was to explore if the expression of CD2AP is associated with any clinical features of GC and to elucidate the underlying mechanism. Immunohistochemistry of 620 patient tissue samples indicated that the expression of CD2AP is downregulated in DGC. Moreover, a low CD2AP level was indicative of poor patient prognosis. In vitro, forced expression of CD2AP caused a significant decrease in the migration and invasion of GC cells, whereas depletion of CD2AP had the opposite effect. Immunofluorescence analysis indicated that CD2AP promoted cellular adhesion and influenced cell cytoskeleton assembly via interaction with the F-actin capping protein CAPZA1. Overall, the upregulation of CD2AP could attenuate GC metastasis, suggesting CD2AP as a novel biomarker for the prognosis and treatment of patients with GC.

Three-Dimensional Ex Vivo Culture for Drug Responses of Patient-Derived Gastric Cancer Tissue.

Gastric cancer (GC) is one of the most common malignancies with high mortality and substantial morbidity. Although the traditional treatment strategies for GC revolve around surgery, radiotherapy, and chemotherapy, none have been able to optimally treat most affected patients. To improve clinical outcomes and overcome potential GC resistance, we established a three-dimensional (3D) culturing platform that accurately predicts drug responses in a time- and cost-effective manner. We collected tumor tissues from patients following surgeries and cultured them for 3 days using our protocol. We first evaluated cell proliferation, viability, and apoptosis using the following markers: Ki67 and cleaved caspase 3 (Cas3). We demonstrated that cell viability was maintained for 72 h in culture and that the tumor microenvironments and vascular integrities of the tissues were intact throughout the culture period. We then administered chemotherapeutics to assess drug responses and found differential sensitivity across different patient-derived tissues, enabling us to determine individualized medication plans. Overall, our study validated this rapid, cost-effective, scalable, and reproducible protocol for GC tissue culture that can be employed for drug response assessments. Our 3D culture platform paves a new way for personalized medication in GC and other tumors and can greatly impact future oncological research.

Establishment and Application of a Method for High-Risk Human Papillomavirus Genotyping in Cervical Cancer Tissue.

BACKGROUND: Persistent high-risk HPV infection is a major cause of cervical cancer and E6/E7 genes and the Li gene in the HPV genome are key targets to detect high-risk HPV. This study aims to explore the relationship between cervical lesions and E6/7 by establishing a polymerase chain reaction (PCR) to detect multiplex genes based on HPV EE7 genes. It is hoped that such methods will provide a more reliable method for clinical screening and the prevention of cervical cancer. METHODS: Based on alignment, specific primers were designed for HPV E6/E7 genes, the sequences of which came from five5 high-risk papillomaviruses that are common in China. This enabled an E6/E7 gene detection method based on multiplex PCR to be established. E6/E7 and Li gene testing were then performed on 65 cervical cancer tissue samples. The gene copy number of HPV E6/E7 genes and the Li gene were detected from different classifications by real-time fluorescence quantitative PCR. RESULTS: Out of the 65 cervical cancer tissue samples, 47 (72.31%) showed positive results in E6/E7 multiplex PCR, 21 (32.31%) showed positive results in the Ll gene PCR, and out of the 219 cervical exfoliate cell samples, 56 (25.57%) showed positive results in E6/E7 multiplex PCR, 21 (13.24%) showed positive results in the L1 gene PCR. There were significant differences (p < 0.05) between these two test results. Fluorescent quantitative PCR showed that the ratio of gene copy number of L1 genes and E6/E7 genes was below 1 (p < 0.05) in cervical cancer tissue, in which both the Li and E6/E7 genes coexist. CONCLUSIONS: The established HPV multiplex PCR assay based on the design of E6/E7 gene is a specific and sensitive method for the detection and genotype of five high-risk HPVs.