Gastric Carcinoma Cells Research Articles

Activation of DNA methyltransferase 3a by Epstein-Barr nuclear antigen 1 in gastric carcinoma.

Epstein-Barr nuclear antigen 1 (EBNA1) is expressed in all Epstein-Barr virus (EBV)-infected cells. It interacts with a variety of cellular proteins and activates the transcription of other EBV latency genes, which plays an important role in the persistence of the EBV genome during latent infection. Several studies have shown that EBV infection induces the expression of DNA methyltransferases (DNMTs) and causes extensive methylation of the whole genome in EBV-associated gastric carcinoma (EBVaGC). However, the specific mechanism by which EBV regulates DNMTs expression is still unclear. EBNA1 plasmid and siRNA were transfected to evaluate the effect of EBNA1 on DNMT3a expression. Molecular biology experiments were used to detect the biological function of DNMT3a and its effect on EBV latency in gastric carcinoma cells. We showed that EBNA1 upregulated DNMT3a expression through the E2F1 transcription factor (E2F1) in EBVaGC. DNMT3a knockdown restrained cell proliferation, induced cell cycle arrest, promoted cell apoptosis and suppressed cell migration in vitro. Our results showed a new mechanism for EBV to regulate the expression of DNMT3a. Targeting the EBNA1/E2F1/DNMT3a axis may provide an alternative therapeutic strategy in the treatment of EBVaGC with high DNMT3a expression.

Synthesis, in vitro evaluation and molecular docking studies of novel naphthoisoxazolequinone carboxamide hybrids as potential antitumor agents

Based on previous results with benzoindazolequinone (BIZQ) derivatives, a new series of bioisosteric 3-methylnaphtho[2,3-d]isoxazole-4,9-quinones (NIQs), conjugated with C-protected amino acids as glycine (Gly), L-alanine (Ala), L-phenylalanine (Phe) and L-glutamic acid, were synthesized from NIQ 2, and the chemical structures of intermediates and hybrids were elucidated by spectroscopic techniques. The antiproliferative activity of NIQs was evaluated by in vitro assay on cultured MCF-7 breast adenocarcinoma and KATO III gastric carcinoma cells. All the compounds showed to be cytotoxic against both cell lines, with IC50 values between 22.9 and 215.3 µM. NIQ hybrids 6, 8, and 9, conjugated with Gly, Phe and Glu, respectively, showed to be more cytotoxic, and hybrid 8 also proved to have higher activity than the precursor 2 against MCF-7 cells. Docking studies showed that NIQs exhibited very good binding energies (ΔG bin ) in the active site of proteins that participate in key carcinogenic pathways.

Abstract 1766: SGN-ALPV a novel, investigational vedotin ADC demonstrates highly effective targeting of oncofetal phosphatases ALPP and ALPPL2 in preclinical models

Abstract Antibody-drug conjugates (ADC) leverage the specificity of antibodies to direct the delivery of potent cytotoxic agents to cancer cells. To fully leverage this specificity, targets with significant differential tumor versus normal tissue expression are ideal for ADC development. Placental alkaline phosphatases, ALPP and ALPPL2, are proteins present during fetal development but are found in several tumor types, making them an attractive ADC target. These cell membrane-attached phosphatases form homo- and heterodimers and play key roles in nucleotide recycling. SGN-ALPV is a novel investigational vedotin ADC comprised of a humanized IgG1 monoclonal antibody conjugated to the microtubule disrupting agent monomethyl auristatin E (MMAE) via a protease-cleavable peptide linker that has been clinically validated in multiple ADC programs. Here we characterize the target antigens, ALPP and ALPPL2, and evaluate SGN-ALPV antitumor activity in preclinical models. Immunohistochemistry and genomic data mining showed that ALPP and ALPPL2 have a highly restricted normal tissue expression yet high expression in several solid tumor types including ovarian, endometrial, germ cell, non-small cell lung and gastric carcinomas. Importantly, normal tissue expression is restricted to placenta and reproductive tissue, with low levels in lung tissue. SGN-ALPV utilizes a humanized antibody, h12F3, that is highly specific for both human and cynomolgus monkey ALPP and ALPPL2 proteins, but not other related phosphatases. In vitro, upon binding to SGN APLV, the antigens, ALPP and ALPPL2, are internalized to lysosomal vesicles releasing the MMAE payload, whose cytotoxic features drive mitotic arrest, apoptosis, and the induction of immunogenic cell death. Additionally, SGN-ALPV mediates antibody dependent cellular cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP) in vitro but lacks complement-dependent cytotoxicity. In preclinical studies, SGN-ALPV exhibits robust antitumor activity in cell line- and patient-derived xenograft models of ovarian, lung, pancreatic, and gastric carcinoma including models with both homogenous and heterogeneous expression of ALPP and ALPPL2, consistent with robust bystander activity of vedotin ADCs. Although, the contribution of ADCC and ADCP in vivo is currently unknown, it is expected that the antitumor activity of SGN-ALPV is mediated by MMAE cytotoxicity. SGN-ALPV was well tolerated in non-human primates (NHP) and exhibited linear pharmacokinetic characteristics, with a toxicity profile consistent with other vedotin-based ADCs. In summary, differential expression of ALPP and ALPPL2 in the tumor versus normal tissue, antibody specificity, antitumor activity, and tolerability of SGN-ALPV provide a strong rationale for the initiation of a planned first-in-human Phase 1 clinical study. Citation Format: Sarah Anderson, Nanna Hansen, Robert Lawrence, Aroon T. Chande, David Ortiz, Christopher Carosino, Esther Trueblood, Nicole Stevens, Kerry Klussman, Angela Epp, Bill Arthur, Shyra Gardai, Hector Rincon. SGN-ALPV a novel, investigational vedotin ADC demonstrates highly effective targeting of oncofetal phosphatases ALPP and ALPPL2 in preclinical models [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 1766.

Abstract 5643: YK-2168, a potent and selective small molecule CDK9 inhibitor

Abstract Objective: Cyclin-dependent kinase 9 (CDK9), which regulates transcriptional elongation, is an attractive therapeutic target for many cancers, especially for cancers driven by transcriptional dysregulation. Specifically, CDK9 mediated transcriptional regulation of short-lived antiapoptotic proteins is critical for the survival of transformed cells. Emerging evidence indicates that selective CDK9 inhibition may provide a therapeutic benefit against certain cancers. We disclose here for the first time a novel CDK9 inhibitor YK-2168 a clinical candidate and its preclinical results. Method: The biochemical activities of YK-2168 for CDK9, CDK1 and CDK2 were measured by literature methods (Tinggui, 2014). The in vitro anti-proliferative activity was evaluated on selected leukemia cell line MV4-11, lymphoma cell line Karpas422 and gastric carcinoma cell line SNU16. The in vivo antitumor activity of YK-2168 was evaluated in cell-derived xenograft (CDX) models of Leukemia (MV4-11) and gastric carcinoma (SNU16), YK-2168 was administered by intravenous (IV) injection. PK/PD was assessed by western blot analysis of pS2-RNA Pol ll CTD expression and cleaved caspase 3 level in the treated tumor tissues. Result: YK-2168 displayed potent selective inhibitory biochemical activity for CDK9 (IC50 : 7.5 nM), but that of CDK1 and CDK2 were modest (IC50 : 466.4 and 361.1 nM), indicative of good selectivity for CDK9. It also showed good anti-proliferative activities in tumor cell lines of different types, MV4-11 potency IC50 of 53.4 nM, Karpas422 potency IC50 of 91.1 nM, and SNU16 potency IC50 of 88.3 nM. YK-2168 showed in vivo antitumor activity in a MV4-11 CDX model with TGI =80 % @10 mpk QW (IV with 4 doses), compared with the same dose of BAY1251152 (TGI =65 % @10 mpk, QW). YK-2168 also showed good regressive antitumor activity in vivo in a SNU16 CDX model with TGI =115 % @10 mpk QW (while BAY1251152 totally inhibited growth with TGI =100%). Western blot analysis of the tumor samples showed that YK-2168 can also inhibit the expression of CDK9 downstream signal proteins and induced apoptosis in a dose-dependent manner. Conclusion: We have discovered a potent and selective small molecule CDK9 inhibitor YK-2168, which showed potent CDK9 inhibition and strong antitumor activity in both in vitro and in vivo preclinical tumor models. These results together with GLP safety results are considered highly promising and warrant moving the compound forward to clinical investigation. In fact, YK-2168 was granted phase I clinical trials in both US and China. Citation Format: Charles Z. Ding, Yingchun Liu, Wang Zhou. YK-2168, a potent and selective small molecule CDK9 inhibitor [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5643.

Abstract 3292: Double targeting oncolytic herpes simplex virus type 1 (oHSV-1) exhibits effective antitumor activity against EpCAM-expressing cancer cells

Abstract Oncolytic virotherapy is a new modality of immunotherapy using spontaneously occurring or genetically engineered viruses to selectively replicate in and kill cancer cells, no harming normal cells. Currently, various oncolytic herpes simplex virus (oHSVs) with enhanced tumor targeting, antitumor efficacy, and safety have been explored in many different models, and on a range of tumor targets. It has been a difficult task to completely retarget HSV to cancer-specific antigens at the plasma membrane of selected tumors, while maintaining the fully lytic potential of HSV. This approach achieved by a deep knowledge of virus natural receptor recognition, binding, and entry mechanisms. Two strategies have been employed including the incorporation of single-chain antibodies (scFv) into gD, gC or gH and the use of soluble adapter molecules that are capable of binding to both HSV and the specific receptor on the target cell. In the previous study, we first reported that HSV could retarget to gastric carcinoma cells by HVEM-CEA adapter molecule. Although we have been shown reasonable efficiency of retargeted cell transduction in vitro and in vivo, it required purification of the adapter protein and continuous addition to the virus prior to infection. To overcome the limitations of adapter molecules, we developed a self-retargeting system by incorporation of adapter expression cassette into the HSV genome that enables the sustained secretion of adapter protein while the viral replication in infected tumor cells. Furthermore, to strengthen the retargeting modality, we constructed a novel, double targeted oHSV, carries no deletion/attenuation, consisting of self-retargeting adapter and modified gH to EpCAM. Our results show that the initial infection and subsequent viral spread depend on cellular EpCAM expression. When injected intravenously (i.v.), they caused no harm to tumor-free mice up to the maximum tested dosage (2 x 108 PFU). When a single intratumoral dose of double targeting oHSV (2 x 106 infectious units) were administered in a xenograft model they rendered 80% of mice tumor-free. Our findings suggest that the double retargeting platform of HSV carrying self-retargeting adapter and modified gH may be potent in cancer-specific cell killing and thus useful for the treatment of EpCAM expressing various cancers. Citation Format: Hyunjung Baek, Hyun-Yoo Joo, Eun-Ran Park, Chun-Seob Ahn, Sujung Lee, Hyeri Kim, Mihee Han, Bora Kim, Heechung Kwon. Double targeting oncolytic herpes simplex virus type 1 (oHSV-1) exhibits effective antitumor activity against EpCAM-expressing cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3292.

Impact of Amarogentin on Gastric Carcinoma Cell Multiplication, Apoptosis and Migration via circKIF4A/miR-152-3p

Objective The active ingredients extracted from natural plants have anti-GC actions and can slow down gastric carcinoma (GC) progression. To investigate the impact of Amarogentin (AG) on GC cell multiplication, apoptosis and migration and the possible mechanisms. Methods qRT-PCR quantification of circKIF4A and miR-152-3p in GC tissues and normal counterparts as well as HGC-27 (human GC cell strain) and GES-1 (human gastric mucosal epithelial cell strain) was performed. HGC-27 cells were intervened by AG of various concentrations. si-NC, si-circKIF4A were further transfected into HGC-27 cells. Besides, pcDNA and pcDNA-circKIF4A were transfected into HGC-27 cells, after which 60 mmol/L AG was added for intervention. Cell multiplication, clone formation, as well as apoptosis and migration measurements were made by MTT, plate clone formation, flow cytometry and Transwell assays, respectively; Double luciferase reporter assay was performed for targeting relationship identification between circKIF4A and miR-152-3p; Western blots were carried out to measure Bax and Bcl-2 protein levels. Results circKIF4A increased (P <0.05) and miR-152-3p decreased (P <0.05) in GC tissues and cell strains. Concentration-dependently, AG intervention contributed to enhanced cell multiplication inhibitory rate, apoptosis rate, miR-152-3p expression and Bax protein level (P <0.05), together with declined number of cell clones formed, migrating cells, circKIF4A expression and Bcl-2 protein level (P <0.05). After transfection of si-circKIF4A, cell multiplication inhibition rate, apoptosis rate and Bax protein level enhanced (P <0.05), while cell clones formed and migrating cells as well as Bcl-2 protein level reduced (P <0.05). miR-152-3p can be controlled by circKIF4A; pcDNA-circKIF4A transfection antagonized AG's effects on HGC-27 cell multiplication, clone formation, apoptosis and migration. Conclusion AG can decrease GC multiplication, clone formation and migration and induce apoptosis via modulating circKIF4A/miR-152-3p expression.

18β-glycyrrhetinic acid regulates mitochondrial ribosomal protein L35-associated apoptosis signaling pathways to inhibit proliferation of gastric carcinoma cells.

BACKGROUNDGastric carcinoma (GC) is a common gastrointestinal malignancy worldwide. Based on the cancer-related mortality, the current prevention and treatment strategies for GC still show poor clinical results. Therefore, it is important to find effective drug treatment targets. AIMTo explore the mechanism by which 18β-glycyrrhetinic acid (18β-GRA) regulates mitochondrial ribosomal protein L35 (MRPL35) related signal proteins to inhibit the proliferation of GC cells. METHODSCell counting kit-8 assay was used to detect the effects of 18β-GRA on the survival rate of human normal gastric mucosal cell line GES-1 and the proliferation of GC cell lines MGC80-3 and BGC-823. The apoptosis and cell cycle were assessed by flow cytometry. Cell invasion and migration were evaluated by Transwell assay, and cell scratch test was used to detect cell migration. Furthermore, a tumor model was established by hypodermic injection of 2.5 × 106 BGC-823 cells at the selected positions of BALB/c nude mice to determine the effect of 18β-GRA on GC cell proliferation, and quantitative reverse transcription-polymerase chain reaction (qRT-PCR) was used to detect MRPL35 expression in the engrafted tumors in mice. We used the term tandem mass tag (TMT) labeling combined with liquid chromatography–tandem mass spectrometry to screen for differentially expressed proteins (DEPs) extracted from GC cells and control cells after 18β-GRA intervention. A detailed bioinformatics analysis of these DEPs was performed, including Gene Ontology annotation and enrichment analysis, Kyoto Encyclopedia of Genes and Genomes pathway enrichment analysis, and so on. Moreover, STRING database (https://string-db.org/) was used to predict protein-protein interaction (PPI) relationships and Western blot was used to detect the expression of proteins of interest in GC cells. RESULTSThe results indicated that 18β-GRA could inhibit the proliferation of GC cells in a dose- and time-dependent manner. It could induce GC cell apoptosis and arrest the cell cycle at G0/G1 phase. The proportion of cells arrested at S phase decreased with the increase of 18-GRA dose, and the migration and invasiveness of GC cells were inhibited. The results of animal experiments showed that 18β-GRA could inhibit tumor formation in BALB/c nude mice, and qRT-PCR results showed that MRPL35 expression level was significantly reduced in the engrafted tumors in mice. Using TMT technology, 609 DEPs, among which 335 were up-regulated and 274 were down-regulated, were identified in 18β-GRA intervention compared with control. We found that the intervention of 18β-GRA in GC cells involved many important biological processes and signaling pathways, such as cellular processes, biological regulation, and TP53 signaling pathway. Notably, after the drug intervention, MRPL35 expression was significantly down-regulated (P = 0.000247), TP53 expression was up-regulated (P = 0.02676), and BCL2L1 was down-regulated (P = 0.01699). Combined with the Retrieval of Interacting Genes/Proteins database, we analyzed the relationship between MRPL35, TP53, and BCL2L1 signaling proteins, and we found that COPS5, BAX, and BAD proteins can form a PPI network with MRPL35, TP53, and BCL2L1. Western blot analysis confirmed the intervention effect of 18β-GRA on GC cells, MRPL35, TP53, and BCL2L1 showed dose-dependent up/down-regulation, and the expression of COPS5, BAX, and BAD also increased/decreased with the change of 18β-GRA concentration.CONCLUSION18β-GRA can inhibit the proliferation of GC cells by regulating MRPL35, COPS5, TP53, BCL2L1, BAX, and BAD.

Anticancer effects of zapotin flavone in human gastric carcinoma cells are mediated via targeting m-TOR/PI3K/AKT signalling pathway.

The current study aims to investigate the anticancer effects of zapotin flavone in human gastric carcinoma cells. MTT assay was performed to determine the cytotoxicity effects of zapotin against the gastric cancer cells (SNU-1) and normal gastric cells (GES-1). SNU-1 cell morphology was analyzed through phase-contrast microscopy. Apoptosis was identified through DAPI staining assay and quantified through annexin V/propidium iodide (PI) staining. The effects on cell migration and invasion were carried out through transwell assay. Apoptosis and m-TOR/PI3K/AKT signalling pathway related proteins were analysed through western blotting. Proliferation rate of gastric cancer SNU-1 cell line declined with enhanced zapotin concentrations in comparison to normal GES-1 cells. Substantial morphological changes after zapotin exposure, including nuclear condensation and membrane rupture was observed. Further, increasing number of apoptotic cells, suppression of both cell migration and invasion was observed with increased zapotin concentrations. Finally, western blotting indicated significant blocking of m-TOR/PI3K/AKT signalling pathway. We conclude that zapotin can act as a potential drug against the gastric cancer.

Gasdermin B over-expression modulates HER2-targeted therapy resistance through LC3B/Rab7 interaction

Tumor resistance to therapy is one of the most important challenges in current oncology. A clear example of this major issue is the HER2-positive tumors characterized by ERBB2 (HER2/neu) overexpression. HER2+ overexpression/ amplification occurs in several tumors, especially in breast and gastric carcinomas that show an aggressive phenotype traditionally associated to poor prognosis. In fact, despite the clinical outcome of these tumors has gradually improved, due to the development of different antiHER2 therapies, many patients will not respond to these treatments or develop acquired resistance. Several potential resistance mechanisms to these targeted therapies have been described. Among them, our laboratory established, for the first time, that the amplification/overexpression of Gasdermin B (GSDMB), which occurs in more than 60% HER2+ breast cancer patients, is a marker of poor prognosis. Moreover, our data in HER2+ tumors revealed that GSDMB overexpression correlated to distant metastasis, poor clinical outcome, and reduced response to anti-HER2 therapies. In this context, we have attempted to elucidate the molecular mechanism whereby GSDMB collaborates in the resistance to anti-HER2 therapies. To decipher the functional relevance of GSDMB in promoting resistance to HER2-targeted therapies we performed several molecular approaches (immunoblot, flow cytometry, immunoprecipitation, etc.) in different breast and gastric carcinoma cell models. Finally, we validated the efficacy of the identified targeted treatment using two complementary in vivo preclinical models (mice and zebrafish). Our results confirmed that similarly to HER2 breast tumors, GSDMB is also over-expressing in more than 50% in HER2 gastric tumors. Furthermore, this over-expression renders HER2 breast and gastric cancer cells more resistant to anti- HER2 agents by promoting protective autophagy. Consistent with this, we proved that the combination of lapatinib with the autophagy inhibitor chloroquine increases the therapeutic response specifically in GSDMB-positive tumors in vitro and in vivo. Mechanistically, we also confirmed that GSDMB forms a complex with LC3B and Rab7. Finally, we validated these results in clinical samples of HER2 breast and gastric cancers, where GSDMB/LC3B/Rab7 co- expression associates significantly with relapse. In conclusion, our data decipher the molecular mechanism that underlies the relation between Gasdermin B and pro-survival autophagy with the final goal of finding a therapy that would be effective in overcoming resistance to anti-HER2 standard therapies in HER2/GSDMB+ tumors.

Comprehensive analysis of FGFR mutations in Chinese cancer patients.

e15117 Background: Fibroblast growth factor receptors (FGFRs) are highly conserved transmembrane tyrosine kinase receptors (RTKS) that regulating several cellular processes such as proliferation, differentiation, migration and survival. In recent years, some studies have documented that signaling through FGFRs impact progression of cancer and the survival of patients with cancer. As a potential therapeutic target, exploring the mutation frequency of FGFRs in more different cancers are necessary. Here we performed a comprehensive analysis of the frequency and types of FGFRs mutations in Chinese cancer patients and provided reference for targeted therapy development. Methods: From January 2020 to December 2021, a total of 4,102 patients with nine common cancers were included in the study. The next-generation sequencing was utilized for detecting genetic mutations. Results: A total 328 patients (7.9%) with FGFR mutation were identified. The FGFR 3 was the most frequently gene in our cohort. Among all the cancer patients, the highest frequency of FGFR mutations was observed in bladder cancer (32.5%) and the percentages in FGFR1, FGFR2 and, FGFR3 were 2.7%, 1.35%, and 6.76% respectively. Furthermore, the proportion of FGFR mutation in lung carcinoma, cholangiocarcinoma, colorectal carcinoma, melanoma, breast carcinoma and ovarian carcinoma was 8.64%, 11.58%, 13%, 16.7%, 9.62% and 10.81% respectively. Additionally, FGFR mutation have been detected in other tumor types, including renal cell carcinoma (5.63%), prostate cancer (5.45%), and gastric carcinoma (13.72%). Conclusions: The present study provided the comprehensive FGFR mutation data of Chinese cancer patients. A high frequency mutation in FGFR have been found in Chinese patients with different cancers, which mean that patients with multiple cancer types might benefit from development of efficient EGFR inhibitors.

Double Trouble – Synchronous Primary Malignant Neoplasms: A Case Report

Synchronous primary malignancy (SPM) is rare. We herein present a case of gastric carcinoma (GC) and renal cell carcinoma (RCC) to highlight the fact that the occurrence of RCC as a synchronous tumor along with GC is rare and that a high index of suspicion of SPM should be considered before declaring it as a metastasis. A 60-year-old male presented with abdominal pain and vomiting for 4 months, and a mass was incidentally found in the lumbar region. The patient was diagnosed with SPM of the GC and RCC. Chemotherapy was given, followed by total gastrectomy; radical nephrectomy was performed. The patient is currently on follow-up. Complete history taking and thorough physical examination of patients with malignancy is instrumental in ruling out metastasis and other synchronous lesions, especially in GC. Synchronous malignancies should be treated with the multidisciplinary team, as there is no consensus in the treatment protocol

Precise engineering of cholesterol-loaded chitosan micelles as a promising nanocarrier system for co-delivery drug-siRNA for the treatment of gastric cancer therapy

Anticancer therapy involving chemotherapeutic drugs and therapeutic small interfering RNA (siRNA) in cancer cell lines that improves cell-killing ability and reduces side effects compared with the existing therapeutics is encouraging. However, simultaneous delivery to tumor is challenging. In this study, the self-assembled strategic delivery of the therapeutic drug salinomycin (SAL) and siRNA to cancer cells was demonstrated. Chitosan is a popular choice in the application as a drug delivery carrier due to its biocompatibility, chemical versatility, aqueous solubility, and low cost. Cholesterol-loaded chitosan nanoparticles (C) with SAL (C-SAL and siRNA@C-SAL) were physically and chemically characterized using the particle size and zeta potential. The siRNA@C-SAL has been effectively considered in a time-dependent manner by human gastric cells SNU-668 and SGC-791. The siRNA@C-SAL displayed superior in vitro cytotoxicity against two gastric carcinoma cells (SNU-668 and SGC-791). Toxicity studies using healthy mice revealed that the use of siRNA@C-SAL did not cause any significant adverse effects, whereas bare drugs caused considerable organ damage. Furthermore, the in vivo antitumor efficacy of siRNA@C-SAL was demonstrated in SNU-668 tumor-bearing mice, and no weight loss was observed in mice. Moreover, antitumor effectiveness was evaluated using hematoxylin and eosin staining. Therefore, the proposed combination therapy using an improved drug delivery system with siRNA and hydrophobic drugs provides a potential strategy for the treatment of gastric cancer.

A comprehensive analysis of potential gastric cancer prognostic biomarker ITGBL1 associated with immune infiltration and epithelial–mesenchymal transition

BackgroundIntegrin, beta-like 1 (ITGBL1) is involved in a variety of human malignancies. However, the information on the involvement of ITGBL1 in gastric carcinoma (GC) is limited. Hence, this study aimed further to explore the functions and mechanisms of ITGBL1 in GC.MethodsFirst, multiple bioinformatics databases, including Oncomine, Tumor Immune Estimation Resource, UALCAN, and Kaplan–Meier Plotter, were used to predict the expression level and prognostic value of ITGBL1, as well as its association with immune infiltration and epithelial–mesenchymal transition (EMT) in GC. Quantitative reverse transcription–polymerase chain reaction and immunohistochemical analysis were used to detect the expression of ITGBL1 in both GC tissues and cells. Then, targeted silencing of ITGBL1 in GC cells was further used to examine the biological functions of ITGBL1.ResultsThese databases revealed that ITGBL1 was overexpressed and affected the overall survival in GC. Besides, the expression of ITGBL1 positively correlated with immune-infiltrating cells and EMT-related markers. Subsequently, molecular biology experiments verified these predictions. In GC tissues and cells, ITGBL1 was notably overexpressed. Loss-of-function studies showed that the knockdown of ITGBL1 significantly suppressed migration and invasion but promoted apoptosis in MGC803 GC cells. Furthermore, the inhibition of ITGBL1 resulted in remarkably increased protein expression levels of cadherin 1, while the expression of Vimentin, Snail, and transforming growth factor-β1 was downregulated, indicating the initiation and progression of GC caused by ITGBL1 partly via inducing EMT.ConclusionsTo sum up, the findings indicated that ITGBL1 acted as a valuable oncogenic factor in GC.

TRF-Val-CAC-016 modulates the transduction of CACNA1d-mediated MAPK signaling pathways to suppress the proliferation of gastric carcinoma

BackgroundAs a new kind of non-coding RNAs (ncRNAs), tRNA derivatives play an important role in gastric carcinoma (GC). Nevertheless, the underlying mechanism tRNA derivatives were involved in was rarely illustrated.MethodsWe screened out the tRNA derivative, tRF-Val-CAC-016, based on the tsRNA sequencing and demonstrated the effect tRF-Val-CAC-016 exerted on GC proliferation in vitro and in vivo. We applied Dual-luciferase reporter assay, RIP assay, and bioinformatic analysis to discover the downstream target of tRF-Val-CAC-016. Then CACNA1d was selected, and the oncogenic characteristics were verified. Subsequently, we detected the possible regulation of the canonical MAPK signaling pathway to further explore the downstream mechanism of tRF-Val-CAC-016.ResultsAs a result, we found that tRF-Val-CAC-016 was low-expressed in GC, and upregulation of tRF-Val-CAC-016 could significantly suppress the proliferation of GC cell lines. Meanwhile, tRF-Val-CAC-016 regulated the canonical MAPK signaling pathway by targeting CACNA1d.ConclusionstRF-Val-CAC-016 modulates the transduction of CACNA1d-mediated MAPK signaling pathways to suppress the proliferation of gastric carcinoma. This study discussed the function and mechanism of tRF-Val-CAC-016 in GC for the first time. The pioneering work has contributed to our present understanding of tRNA derivative, which might provide an alternative mean for the targeted therapy of GC.AKy7v1UFnnMKc3sU1zEgwPVideo abstract

Downregulation of LINC01857 Increases Sensitivity of Gastric Carcinoma Cells to Cisplatin.

Background The critical roles of long noncoding RNAs (lncRNAs) in the carcinogenesis and progression of cancers have been well documented. It was reported that lncRNAs were involved in chemotherapy resistance in various cancers. This study was aimed at clarifying the role of LINC01857 in cisplatin (DDP) resistance in gastric carcinoma (GC). Methods The Cancer Genome Atlas (TCGA) database was used to analyze the expression of LINC01857 in GC tissues and normal tissues. The expression of LINC01857 in GC cells and DDP-resistant GC cells was detected by qRT-PCR. Cell viability and IC50 value were evaluated using the MTT assay. Moreover, cell apoptosis, migration, and invasion were determined using flow cytometry and Transwell assays, respectively. The expression of apoptosis-related proteins was examined by western blot. Results TCGA database analysis revealed that LINC01857 expression was elevated in GC tissues compared with the normal tissues. qRT-PCR showed that the expression of LINC01857 was significantly higher in DDP-resistant cells than in GC and normal gastric cells. Knockdown of LINC01857 reduced cell viability in DDP-resistant cells. Moreover, LINC01857 downregulation promoted cell apoptosis and inhibited cell migration and invasion in DDP-resistant GC cells. Conclusions LINC01857 was highly expressed in GC. Additionally, LINC01857 knockdown could facilitate the sensitivity to DDP and apoptosis and repressed cell migration and invasion in DDP-resistant GC cells, which provided a novel therapeutic target for chemotherapy resistance of GC in clinical practice.

Systematic molecular analysis of the human secretome and membrane proteome in gastrointestinal adenocarcinomas.

The human secretome and membrane proteome are a large source of cancer biomarkers. Membrane‐bound and secreted proteins are promising targets for many clinically approved drugs, including for the treatment of tumours. Here, we report a deep systematic analysis of 957 adenocarcinomas of the oesophagus, stomach, colon and rectum to examine the cancer‐associated human secretome and membrane proteome of gastrointestinal tract adenocarcinomas (GIACs). Transcriptomic data from these GIACs were applied to an innovative majority decision‐based algorithm. We quantified significantly expressed protein‐coding genes. Interestingly, we found a consistent pattern in a small group of genes found to be overexpressed in GIACs, which were associated with a cytokine–cytokine interaction pathway (CCRI) in all four cancer subtypes. These CCRI associated genes, which spanned both one secretory and one membrane isoform were further analysed, revealing a putative biomarker, interleukin‐1 receptor accessory protein (IL1RAP), which indicated a poor overall survival, a positive correlation with cancer stemness and a negative correlation with several kinds of T cells. These results were further validated in vitro through the knockdown of IL1RAP in two human gastric carcinoma cell lines, which resulted in a reduced indication of cellular proliferation, migration and markers of invasiveness. Following IL1RAP silencing, RNA seq results showed a consistent pattern of inhibition related to CCRI, proliferation pathways and low infiltration of regulatory T cells (Tregs) and CD8 naive cells. The significance of the human secretome and membrane proteome is elucidated by these findings, which indicate IL1RAP as a potential candidate biomarker for cytokine‐mediated cancer immunotherapy in gastric carcinoma.

Role of lncSLCO1C1 in gastric cancer progression and resistance to oxaliplatin therapy.

BackgroundGastric carcinoma (GC) is one of the most deadly diseases due to tumour metastasis and resistance to therapy. Understanding the molecular mechanism of tumour progression and drug resistance will improve therapeutic efficacy and develop novel intervention strategies.MethodsDifferentially expressed long non‐coding RNAs (lncRNAs) in clinical specimens were identified by LncRNA microarrays and validated in different clinical cohorts by quantitative real‐time polymerase chain reaction (qRT‐PCR), in situ hybridisation and bioinformatics analysis. Biological functions of lncRNA were investigated by using cell proliferation assays, migration assays, xenograft tumour models and bioinformatics analysis. Effects of lncSLCO1C1 on GC cell survival were assessed by comet assays and immunofluorescence assays. Underlying molecular mechanisms were further explored by using a number of technologies including RNA pull‐down, mass spectrometry analysis, RNA immunoprecipitation, co‐immunoprecipitation, miRNA sequencing, luciferase reporter assays and molecular modelling.ResultsLncSLCO1C1 was highly upregulated in GC tissue samples and associated with GC patients’ poor overall survival. Overexpression of lncSLCO1C1 promoted proliferation and migration, whereas decreased lncSLCO1C1 expression produced the opposite effects. lncSLCO1C1 also mediated tumour resistance to chemotherapy with oxaliplatin by reducing DNA damage and increasing cell proliferation. Despite sequence overlapping between lncSLCO1C1 and PDE3A, alternations of PDE3A expression had no effect on the GC cell progression, indicating that lncSLCO1C1, not PDE3A, related with the progression of GC cells. Mechanistically, lncSLCO1C1 serves as a scaffold for the structure‐specific recognition protein 1 (SSRP1)/H2A/H2B complex and regulates the function of SSRP1 in reducing DNA damage. Meanwhile, lncSLCO1C1 functions as a sponge to adsorb miR‐204‐5p and miR‐211‐5p that target SSRP1 mRNA, and thus increases SSRP1 expression. Patients with high expressions of both lncSLCO1C1 and SSRP1 have poor overall survival, highlighting the role of lncSLCO1C1 in GC progression.ConclusionsLncSLCO1C1 promotes GC progression by enhancing cell growth and preventing DNA damage via interacting and scaffolding the SSRP1/H2A/H2b complex and absorbing both miR‐211‐5p and miR‐204‐5p to increase SSRP1 expression.

Clinical significance and correlation of miR-200c and P-gp expression in gastric cancer and the effects on multidrug resistance.

Poor prognosis is common in gastric cancer patients due to multidrug resistance (MDR)-induced recurrence and metastasis. In the present study, we investigated the expression of microRNA (miR)-200c in gastric cancer tissues and cell lines and its relationship with the expression of the drug resistant gene ABCB1, which encodes P-glycoprotein (P-gp). The basic characteristics of 102 patients with gastric cancer were reviewed. Real time-polymerase chain reaction (PCR), immunohistochemistry, and Western blot were employed to detect the expression levels of miR-200c and P-gp in gastric carcinoma tissues and cell lines. The correlation of miR-200c messenger RNA (mRNA) level with clinicopathological characteristics and P-gp protein expression were analyzed. SGC7901/vincristine (VCR) cells were transfected with miR-200c mimics or a specific small interfering RNA (siRNA) targeting the ABCB1 gene. The methyl thiazolyl tetrazolium (MTT) assay and flow cytometry were used to determine the role of miR-200c and ABCB1 on the viability and apoptosis of gastric carcinoma cell lines. The level of miR-200c in carcinoma tissues was significantly lower than that in adjacent tissues, and the expression level of P-gp in carcinoma tissues was obviously higher than that in adjacent tissues (P<0.01, P=0.029). The expression levels of miR-200c and P-gp were associated with the malignant characteristics of gastric cancer, and patients with high expression of miR-200c or negative expression of P-gp had a better prognosis (P=0.006, P=0.022). MiR-200c negatively regulated the ABCB1 gene in gastric cancer cell lines. MiR-200c overexpression and ABCB1 down-regulation increased the sensitivity of SGC7901/VCR cells to VCR and reversed MDR by promoting cell apoptosis. The expression level of miR-200c decreases in gastric carcinoma tissues and drug-resistant gastric cancer SGC7901/VCR cells. Overexpression of miR-200c may enhance the sensitivity of SGC7901/VCR cells to VCR by regulating the expression of P-gp.

Dynamic detection of HER2 of circulating tumor cells in patients with gastric carcinoma and its clinical application.

The aim of the present study was to construct and characterize human epidermal growth factor receptor2 (HER2) lipid magnetic ball (H‑LMB) for separating circulating tumor cells (CTCs) in patients with gastric carcinoma (GC) and to compare the result of separated CTC counts with that of next‑generation sequencing (NGS) for single‑gene analysis to verify the consistency for evaluating the association between the detection results and the progress of clinical treatment, so as to facilitate early diagnosis and dynamic monitoring of GC. A lipid magnetic ball (LMB), coated with Fe3O4 nanoparticles, was synthesized by microemulsion technique and an anti‑HER2 antibody was conjugated to the surface of LMB to form H‑LMB, followed by the characterization of the prepared H‑LMB. The detection of capture efficiency of LMBs in GC cells was tested by MTT and expression of HER2 mRNA was determined by reverse transcription‑quantitative PCR. The positive detection rate of HER2 was verified by HER2‑fluorescence insitu hybridization (FISH) test on the separated CTCs from GC. Further verification was performed based on the consistency between the result of separated CTCs and that of single‑gene NGS assay of HER2, associated with the determination of clinical consistency. The constructed H‑LMB exhibited good stability and specificity. The mutation rate of HER2 by the FISH test was 14% in the blood samples of 50patients with GC and was 14% by NGS assay. The mutation rate of HER2 was 12% in H‑LMB and the positive detection rate was 85.7% compared with the results of the FISH test, indicating consistency with the clinical diagnosis and pathological examination results. In conclusion, the anti‑HER2 antibody‑modified LMB can separate CTCs with HER2 abnormal expression, which exhibits an application potential in GC diagnosis and treatment and is of great clinical significance for the diagnosis and evaluation of its therapeutic effect on GC.

Male-specific long non-coding RNA testis-specific transcript, Y-linked 15 promotes gastric cancer cell growth by regulating Wnt family member 1/β-catenin signaling by sponging microRNA let-7a-5p

ABSTRACT The present study is aimed to investigate the regulatory effects and related mechanism of long non-coding RNA testis-specific transcript, Y-linked 15 (TTTY15) in gastric carcinoma (GC) cell proliferation, migration, invasion, apoptosis and epithelial–mesenchymal transition (EMT). TTTY15 expression in GC tissue samples and cells was detected by quantitative real-time PCR (qRT-PCR), and the correlation between TTTY15 expression and GC clinicopathological indicators was analyzed. Cell counting kit-8 (CCK-8), BrdU, flow cytometry and Transwell assays were performed for detecting GC cell proliferation, migration, invasion and apoptosis. Western blot was performed for detecting the expressions of EMT-associated proteins (N-cadherin and E-cadherin), Wnt family member 1 (Wnt1) protein and β-catenin protein. Bioinformatics analysis was conducted to predict, and RNA immunoprecipitation (RIP) assay and dual-luciferase reporter gene assay were performed to verify the targeted relationships of microRNA let-7a-5p (let-7a-5p) with TTTY15 and Wnt1 mRNA 3'UTR. It was found that TTTY15 expression was significantly up-regulated in GC tissues and cells, and was associated with advanced TNM stage and poor tumor differentiation. TTTY15 overexpression promoted GC cell proliferation, migration and invasion, the expressions of N-cadherin, Wnt1 and β-catenin protein, and inhibited the apoptosis and E-cadherin expression, while knocking down TTTY15 had the opposite effects. TTTY15 directly targeted let-7a-5p and negatively regulated its expression. Wnt1 was the target gene of let-7a-5p, and TTTY15 could indirectly and positively regulate Wnt1 expression. In conclusion, TTTY15 promotes GC progression, by regulating the let-7a-5p/Wnt1 axis to activate the Wnt/β-catenin pathway.