Mechanisms by which the intestinal microbiota affects gastrointestinal tumours and therapeutic effects.

The intestinal microbiota is considered to be a forgotten organ in human health and disease. It maintains intestinal homeostasis through various complex mechanisms. A significant body of research has demonstrated notable differences in the gut microbiota of patients with gastrointestinal tumours compared to healthy individuals. Furthermore, the dysregulation of gut microbiota, metabolites produced by gut bacteria, and related signal pathways can partially explain the mechanisms underlying the occurrence and development of gastrointestinal tumours. Therefore, this article summarizes the latest research progress on the gut microbiota and gastrointestinal tumours. Firstly, we provide an overview of the composition and function of the intestinal microbiota and discuss the mechanisms by which the intestinal flora directly or indirectly affects the occurrence and development of gastrointestinal tumours by regulating the immune system, producing bacterial toxins, secreting metabolites. Secondly, we present a detailed analysis of the differences of intestinal microbiota and its pathogenic mechanisms in colorectal cancer, gastric cancer, hepatocellular carcinoma, etc. Lastly, in terms of treatment strategies, we discuss the effects of the intestinal microbiota on the efficacy and toxic side effects of chemotherapy and immunotherapy and address the role of probiotics, prebiotics, FMT and antibiotic in the treatment of gastrointestinal tumours. In summary, this article provides a comprehensive review of the pathogenic mechanisms of and treatment strategies pertaining to the intestinal microbiota in patients with gastrointestinal tumours. And provide a more comprehensive and precise scientific basis for the development of microbiota-based treatments for gastrointestinal tumours and the prevention of such tumours.

Black Phosphorus Nanosheets Assist Nanoerythrosomes for Efficient mRNA Vaccine Delivery and Immune Activation.

Messenger RNA (mRNA)-based vaccines have enormous potential in infectious disease prevention and tumor neoantigen application. However, developing an advanced delivery system for efficient mRNA delivery and intracellular release for protein translation remains a challenge. Herein, a biocompatible biomimetic system is designed using red blood cell-derived nanoerythrosomes (NER) and black phosphorus nanosheets (BP) for mRNA delivery. BP is covalently modified with polyethyleneimine (PEI), serving as a core to efficiently condense mRNA via electrostatic interactions. To facilitate the spleen targeting of the mRNA-loaded BP (BPmRNA ), NER is co-extruded with BPmRNA to construct a stable "core-shell" nanovaccine (NER@BPmRNA ). The mRNA nanovaccine exhibits efficient protein expression and immune activation via BP-mediated adjuvant effect and enhanced lysosomal escape. In vivo evaluation demonstrates that the system delivery of mRNA encoding coronavirus receptor-binding domain (RBD) significantly increases the antibody titer and pseudovirus neutralization effect compared with that of NER without BP assistance. Furthermore, the mRNA extracted from mouse melanoma tissues is utilized to simulate tumor neoantigen delivered by NER@BPmRNA . In the vaccinated mice, BP-assisted NER for the delivery of melanoma mRNA can induce more antibodies that specifically recognize tumor antigens. Thus, BP-assisted NER can serve as a safe and effective delivery vehicle in mRNA-based therapy.

Directional conjugation of Trop2 antibody to black phosphorus nanosheets for phototherapy in orthotopic gastric carcinoma.

Tumor-associated calcium signal transducer 2 (Trop2) is highly specific expressed in gastric carcinoma (GC). The combination of Trop2 antibody and phototherapy agents could exhibit synergetic antitumor activity. Black phosphorus nanosheets (BP) are covalently modified with Trop2 IgG antibodies via heterobifunctional linker of polyethylene glycol (PEG). Then the Trop2 antibody was directionally conjugated to BP via Schiff base reaction between aldehyde group from oxidized Trop2 antibody and amino group of PEG. The Trop2-functionalzied BP can significantly increase the endocytosis of BP in Trop2-positive GC cells exhibiting a reinforced antitumor activity under near infrared (NIR) irradiation. More importantly, a murine orthotopic GC model demonstrates that Trop2 antibody modification can significantly promote the accumulation of BP at tumor tissues and strengthen antitumoral activity of phototherapy. Directional conjugation of Trop2 antibody to BP facilitates the BP with superior stability, tumor targeting ability and excellent anti-tumor activity under NIR irradiation without systemic toxicity.

POM121 promotes the proliferation and metastasis of gastric cancer via PI3K/AKT/MYC pathway.

Nuclear pore membrane protein 121 (POM121) is a part of the nuclear pore complex, which regulates intracellular signaling and maintains normal cellular functions. However, the role of POM121 in gastric cancer (GC) remains unclear. Quantitative real-time polymerase chain reaction was performed to detect POM121 mRNA in 36 pairs of GC and adjacent non-tumor tissues. POM121 protein expression was determined by immunohistochemistry in 648 GC tissues and 121 normal gastric tissues. Connections between POM121 levels, clinicopathological parameters, and the prognosis of GC patients were explored. The influence of POM121 on proliferation, migration, and invasion was detected in vitro and vivo. The mechanism underlying the involvement of POM121 in GC progression was demonstrated via bioinformatics analysis and Western blot. Both the mRNA and protein levels of POM121 in GC tissues were higher than those in normal gastric tissues. High POM121 expression in GC was associated with deep invasion, advanced distant metastases and TNM stage, and positive HER2 expression. A negative connection was found between POM121 expression and the overall survival (OS) of GC patients. Downregulation of POM121 inhibited the proliferation, clone formation, migration, and invasion of GC cells, and overexpression of POM121 showed the opposite trend. POM121 promoted the phosphorylation of PI3K/AKT pathway and increased the expression of MYC. In conclusion, this study suggested that POM121 has the potential to act as an independent prognostic factor for GC patients.

JAG1 is associated with the prognosis and metastasis in breast cancer.

Jagged canonical Notch ligand 1 (JAG1) regulates the progression of many cancers by the Notch signaling pathway, but its role in breast cancer (BC) remains unclear. In this research, JAG1 protein expression in BC tissues was detected by immunohistochemistry. The association between JAG1 and clinical significance was analyzed. The effect of JAG1 on malignant behaviors of BC cells was demonstrated by in vitro experiments. JAG1 expression in BC tissues was higher than that in para-carcinoma tissues. High JAG1 expression was significantly linked to advanced lymph node metastasis, distant metastasis, and the TNM stage. JAG1 was an independent prognostic factor for BC patients. JAG1 knockdown inhibited the proliferation, motility, migration, and invasion of BC cells, and weakened adhesion and penetration abilities to the blood-brain barrier, whereas JAG1 overexpression had the opposite effects. JAG1 has the potential to be a prognostic marker and therapeutic target for BC patients.

TROP2 Down-regulated DSG2 to Promote Gastric Cancer Cell Invasion and Migration by EGFR/AKT and DSG2/PG/ß-Catenin Pathways.

BACKGROUND: Gastric cancer (GC) is the fourth most commonly found cancer and the second- highest cause of cancer-related death worldwide. TROP2 overexpression is closely related to many cancers, including gastrointestinal tumors. DSG2 is an important protein in cell adhesion, and its loss affects cell migration. AIMS AND OBJECTIVE: This study aimed to explore the specific mechanism of TROP2 in promoting gastric cancer and provide a basis for the prevention and treatment of gastric cancer. METHOD: DSG2 was identified as an interacting protein of TROP2 in GC cells by coimmunoprecipitation and mass spectrometry. The regulated behavior of TROP2 on DSG2 expression was investigated with TROP2 over-expressure or knockdown. Cell-cell adhesion capacity mediated by DSG2 was evaluated by adhesion-related assays. Electron microscope observation was made for accessing GC tumor desmosome assembly. Proteins in EGFR/AKT and DSG2/PG/ß-catenin pathways were evaluated by western blotting. RESULT: This study suggests that abundant expression of TROP2 in GC cells lessened DSG2 levels as well as desmosome adhesion, increased cell invasion and migration, and promoted malignant progression through EGFR/AKT and DSG2/PG/ß-catenin pathways. CONCLUSION: TROP2 promotes cell invasion and migration in gastric cancer by decreasing DSG2 expression through EGFR/AKT and DSG2/PG/ß-catenin pathways.

Single-cell profiling of infiltrating B cells and tertiary lymphoid structures in the TME of gastric adenocarcinomas.

The occurrence and development of gastric adenocarcinoma (gADC) is closely related to the interaction between tumor cells and immune cells in the tumor microenvironment (TME). Our objective was to characterize the repertoire of immune cells in the TME of gADC. To analyze the transcriptomic, immune, and spatial information of TME in gADC, we constructed single-cell RNA sequencing, 10 × Genomics V(D)J analysis, multiple immunofluorescence techniques, and OSCmap analysis of 49,765 single cells in seven samples from four gADC patients. Our integrative analysis of B cells demonstrated that a large number of mucosal associated lymphoid tissue (MALT)-B cells were detected in the gADC tissues, which have mature tertiary lymphatic structures (mTLSs), and almost no MALT-B cells in peripheral blood sample. Moreover, MALT-B cells are a class of IgA+ plasma cells, which are characterized with high expression of complement pathway activation-related genes. Next, natural killer T (NKT) cells mainly exist in gADC tissues accompanied by mTLSs. This study also classified monocytes/macrophages and epithelial cells into benign and malignant types. Interestingly, CSOmap (q < .05) and multiple immunofluorescence (p < .05) results indicated more types of immune cells can be enriched in tissues with mTLSs than normal TLSs, and the density of mTLSs were higher than normal TLSs. Our findings provide novel insights for the signature of immune cells and tumor cells in the TME of gADC with TLSs and highlight the potential importance of IgA-mediated humoral immunity in gADC patients with TLSs.

Corrigendum: CORO1C is Associated with Poor Prognosis and Promotes Metastasis Through PI3K/AKT Pathway in Colorectal Cancer.

[This corrects the article DOI: 10.3389/fmolb.2021.682594.].

Trop2 binding IGF2R induces gefitinib resistance in NSCLC by remodeling the tumor microenvironment.

Gefitinib has shown good efficacy in treating recurrent or advanced non-small cell lung cancer (NSCLC), but the drug resistance remains a clinical challenge in medical oncology. In addition, the complex interaction between tumor cells and heterogeneous stromal cells in the adjacent tumor microenvironment (TME) is also an important contributor to drug resistance. So, it is very necessary to detect the related target genes before and after gefitinib treatment dynamically. In this study, the relationship between Trop2 and gefitinib resistance in NSCLC was investigated, and the underlying mechanism was explored. Results showed that Trop2 was associated with EGFR gene mutation and drug resistance in clinical tissues. Trop2 was confirmed to induce gefitinib resistance in NSCLC, and Trop2 binding IGF2R promoted the IGF2-IGF1R-Akt axis to enhance gefitinib resistance and remodeling the TME in NSCLC. Notably, silencing of Trop2 in cancer cells combined with IGF1R inhibitor significantly decreased the proliferation of tumor cells and reshaped the NSCLC TME in vivo and in vitro, including the recruitment of macrophages. These findings deepened the understanding of the function of Trop2 and the involved mechanisms of gefitinib resistance, and may provide new molecular targets for NSCLC with gefitinib resistance.

TAFs contributes the function of PTPN2 in colorectal carcinogenesis through activating JAK/STAT signaling pathway.

The morbidity and mortality of colorectal cancer (CRC) ranks fourth worldwide, moreover, the tumor microenvironment (TME) of CRC is quite complex, and is one of the necessary factors affecting promotion of tumor metastasis. PTPN2 is a tumor suppressor which plays an important role in cancer-related downstream molecular pathway. FSP-1 is highly-expressed in multiple types of tumor tissues and is a biomarker of stromal fibroblasts. To examine the function of PTPN2 in the metastasis of CRC, the study evaluated the co-expression level of PTPN2 and FSP-1 in CRC tissues by double staining, and demonstrated the relationship with clinical information about each patient. The roles of PTPN2 and FSP-1 were detected in vitro by proliferation and transwell assay through knockdown of expression level of PTPN2. Lower PTPN2 with higher FSP-1 expression was correlated with poor survival outcomes in CRC. TAFs contribute to the migration function of PTPN2 in CRC in vitro through inducing changes in the level of TGF-ß1. Western blot and qRT-PCR assays were used to detect the mechanism of PTPN2 regulation of migration with TAFs in the JAK/STAT signaling pathway, moreover, TAFs contributed the function of PTPN2 in colorectal carcinogenesis in vivo. In summary, the study shed light on the effect of TAFs contributes the function of PTPN2 in colorectal carcinogenesis through activating JAK/STAT signaling pathway. In addition, double-staining assay could give us a unique perspective from which to study TME in CRC.

CORO1C is Associated With Poor Prognosis and Promotes Metastasis Through PI3K/AKT Pathway in Colorectal Cancer.

Trophoblast cell surface protein 2 (Trop2) is one of the cancer-related proteins that plays a vital role in biological aggressiveness and poor prognosis of colorectal cancer (CRC). The study of the Trop2 related network is helpful for us to understand the mechanism of tumorigenesis. However, the effects of the related proteins interacting with Trop2 in CRC remain unclear. Here, we found that coronin-like actin-binding protein 1C (CORO1C) could interact with Trop2 and the expression of CORO1C in CRC tissues was higher than that in paracarcinoma tissues. The expression of CORO1C was associated with histological type, lymph node metastasis, distant metastasis, AJCC stage, venous invasion, and perineural invasion. The correlation between CORO1C expression and clinical characteristics was analyzed demonstrating that high CORO1C expression in CRC patients were associated with poor prognosis. Furthermore, CORO1C knockdown could decrease the cell proliferation, colony formation, migration and invasion in vitro and tumor growth in vivo. The underlying mechanisms were predicted by bioinformatics analysis and verified by Western blotting. We found that PI3K/AKT signaling pathway was significantly inhibited by CORO1C knockdown and the tuomr-promoting role of CORO1C was leastwise partly mediated by PI3K/AKT signaling pathway. Thus, CORO1C may be a valuable prognostic biomarker and drug target in CRC patients.

POM121 promotes proliferation and metastasis in non-small-cell lung cancer through TGF-ß/SMAD and PI3K/AKT pathways.

BACKGROUND: Nuclear pore membrane protein 121 (POM121) is a novel biomarker involved in tumorigenesis and metastasis. However, little is known about the role of POM121 in non-small-cell lung cancer (NSCLC). OBJECTIVE: The aim of this study was to detect the expression of POM121 in NSCLC and its relationship with clinicopathologic feature and cell biological behavior, and explore the underlying mechanisms. METHODS: The expression of POM121 in NSCLC tissues and para-carcinoma tissues was compared by quantitative real-time PCR and immunohistochemistry analysis. The relationship between POM121 protein and clinicopathological characteristics in NSCLC was investigated. Roles of POM121 in NSCLC cells were investigated by CCK-8 assay, clone formation assay, transwell migration and invasion assay, and in vivo experiments. Variations of signaling pathways were determined by qRT-PCR and Western blot. RESULTS: The POM121 expression in NSCLC tissues was significantly higher than that in para-carcinoma tissues, both at the mRNA and protein level. The POM121 expression was related to sex, advanced differentiation, tumor diameter, lymph node metastases, distant metastases, American Joint Committee on Cancer (AJCC) stage, venous invasion, and perineural invasion in NSCLC. Kaplan-Meier analysis indicated that NSCLC patients with high POM121 expression had poor overall survival. Downregulation of POM121 inhibited cell proliferation, clone formation, migration and invasion. TGF-ß/SMAD and PI3K/AKT pathways were involved in POM121-induced functional changes in NSCLC cells. CONCLUSION: POM121 plays an oncogenic role in NSCLC through TGF-ß/SMAD and PI3K/AKT pathways. POM121 expression is a potential independent prognostic factor for NSCLC.

Bispecific c-Met/PD-L1 CAR-T Cells Have Enhanced Therapeutic Effects on Hepatocellular Carcinoma.

T cells expressing chimeric antigen receptors, especially CD19 CAR-T cells have exhibited effective antitumor activities in B cell malignancies, but due to several factors such as antigen escape effects and tumor microenvironment, their curative potential in hepatocellular carcinoma has not been encouraging. To reduce the antigen escape risk of hepatocellular carcinoma, this study was to design and construct a bispecific CAR targeting c-Met and PD-L1. c-Met/PD-L1 CAR-T cells were obtained by lentiviral transfection, and the transfection efficiency was monitored by flow cytometry analysis. LDH release assays were used to elucidate the efficacy of c-Met/PD-L1 CAR-T cells on hepatocellular carcinoma cells. In addition, xenograft models bearing human hepatocellular carcinoma were constructed to detect the antitumor effect of c-Met/PD-L1 CAR-T cells in vivo. The results shown that this bispecific CAR was manufactured successfully, T cells modified with this bispecific CAR demonstrated improved antitumor activities against c-Met and PD-L1 positive hepatocellular carcinoma cells when compared with those of monovalent c-Met CAR-T cells or PD-L1 CAR-T cells but shown no distinct cytotoxicity on hepatocytes in vitro. In vivo experiments shown that c-Met/PD-L1 CAR-T cells significantly inhibited tumor growth and improve survival persistence compared with other groups. These results suggested that the design of single-chain, bi-specific c-Met/PD-L1 CAR-T is more effective than that of monovalent c-Met CAR-T for the treatment of hepatocellular carcinoma., and this bi-specific c-Met/PD-L1 CAR is rational and implementable with current T-cell engineering technology.

DSG2 expression is low in colon cancer and correlates with poor survival.

BACKGROUND: Desmoglein2 (DSG2) is a transmembrane protein that helps regulate intercellular connections and contributes to desmosome assembly. Desmosome are associated with cell adhesion junctions, which play an important role in cancer progression specially cancer cell migration and invasion. However, DSG2 expression in colon cancer (CC) and its association with CC patients' overall survival (OS) are still unclear. METHODS: We collected 587 CC samples, 41 colitis tissues and 114 pericarcinomatous tissues, as well as corresponding clinicopathological data about the patients who contributed them. All samples were tested immunohistochemically in tissue microarrays. Kaplan-Meier method was used for calculating patient survival. Univariate and multivariate analyses was used for investigating DGS2 link with CC patient's clinicopathological factors. Bioinformatics analysis was also used in study. RESULTS: The results showed that DSG2 expression was lower in CC tissues than in pericarcinomatous tissues (P < 0.001). DSG2 expression was associated with differentiation (P = 0.033), lymph node metastasis (P = 0.045), distant metastasis (P = 0.006) and AJCC stage (P < 0.001). Univariate analysis indicated that poor OS in patients with CC was associated with low DSG2 expression (P < 0.001), tumor size (P < 0.001), lymph node metastasis (P < 0.001), distant metastasis (P < 0.001), AJCC stage (P < 0.001) and venous invasion (P < 0.001). In multivariate analysis, low DSG2 expression (P < 0.001), distant metastasis (P < 0.001), AJCC stage (P = 0.002), venous invasion (P < 0.001) were independent prognostic factors for CC patients. Bioinformatics analysis indicated that low DSG2 expression affects protein activation, regulates the P53-related pathway in CC, and activates the EGFR pathway. CONCLUSIONS: The results suggest that low DSG2 expression is associated with poor survival for CC patients. DSG2 could be a prognostic biomarker for CC.

c-Met-targeted chimeric antigen receptor T cells inhibit hepatocellular carcinoma cells in vitro and in vivo.

c-Met is a hepatocyte growth factor receptor overexpressed in many tumors such as hepatocellular carcinoma (HCC). Therefore, c-Met may serve as a promising target for HCC immunotherapy. Modifying T cells to express c-Met-specific chimeric antigen receptor (CAR) is an attractive strategy in treating c-Met-positive HCC. This study aimed to systematically evaluate the inhibitory effects of 2 nd- and 3 rd-generation c-Met CAR-T cells on hepatocellular carcinoma (HCC) cells. Here, 2 nd- and 3 rd-generation c-Met CARs containing an anti-c-Met single-chain variable fragment (scFv) as well as the CD28 signaling domain and CD3ζ (c-Met-28-3ζ), the CD137 signaling domain and CD3ζ (c-Met-137-3ζ), or the CD28 and CD137 signaling domains and CD3ζ (c-Met-28-137-3ζ) were constructed, and their abilities to target c-Met-positive HCC cells were evaluated in vitro and in vivo. All c-Met CARs were stably expressed on T cell membrane, and c-Met CAR-T cells aggregated around c-Met-positive HCC cells and specifically killed them in vitro. c-Met-28-137-3ζ CAR-T cells secreted more interferon-gamma (IFN-γ) and interleukin 2 (IL-2) than c-Met-28-3ζ CAR-T cells and c-Met-137-3ζ CAR-T cells. Compared with c-Met low-expressed cells, c-Met CAR-T cells secreted more cytokines when co-cultured with c-Met high-expressed cells. Moreover, c-Met-28-137-3ζ CAR-T cells eradicated HCC more effectively in xenograft tumor models compared with the control groups. This study suggests that 3 rd-generation c-Met CAR-T cells are more effective in inhibiting c-Met-positive HCC cells than 2 nd-generation c-Met CAR-T cells, thereby providing a promising therapeutic intervention for c-Met-positive HCC.

Trop2 inhibition of P16 expression and the cell cycle promotes intracellular calcium release in OSCC.

Trop2 is an intracellular calcium signal transducer and a prognostic biomarker in many cancers. P16 is a cell cycle gene that negatively regulates cell proliferation and division in most human cancers. Oral squamous cell carcinoma (OSCC) is a common malignant tumor subgroup of head and neck squamous cell carcinoma worldwide. Both Ca2+-dependent and cell cycle signaling pathways play vital roles in OSCC, although the molecular mechanisms remain to be elucidated. We aimed to examine the function of Trop2 and P16 in regulating intracellular calcium ions and the cell cycle in OSCC cell lines. Furtherly, the mRNA and protein expression levels of Trop2 and P16 in OSCC tissue samples were assessed, and their function was evaluated as potential clinical prognostic biomarkers. Trop2 promoted intracellular calcium ion release in OSCC and induced S phase of the cell cycle. Moreover, Trop2-mediated Ca2+ inhibited P16 expression through the AMP-activated protein kinase pathway in OSCC. Interestingly, P16 overexpression could not reverse these phenomena in vitro. We also demonstrated that human OSCC tissues showed high Trop2 mRNA and protein expression, and Trop2+/P16- expression is an independent prognostic marker for OSCC patients. Our data suggest that Trop2+/P16- may be a valuable prognostic marker for OSCC and that Trop2 inhibits P16 expression and induces S phase by promoting intracellular calcium release in OSCC.

Construction of a novel prognostic-predicting model correlated to ovarian cancer.

BACKGROUND: Ovarian cancer (OC) is one of the most lethal gynecological cancers worldwide. The pathogenesis of the disease and outcomes prediction of OC patients remain largely unclear. The present study aimed to explore the key genes and biological pathways in ovarian carcinoma development, as well as construct a prognostic model to predict patients' overall survival (OS). RESULTS: We identified 164 up-regulated and 80 down-regulated differentially expressed genes (DEGs) associated with OC. Gene Ontology (GO) term enrichment showed DEGs mainly correlated with spindle microtubes. For Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways, cell cycle was mostly enriched for the DEGs. The protein-protein interaction (PPI) network yielded 238 nodes and 1284 edges. Top three modules and ten hub genes were further filtered and analyzed. Three candidiate drugs targeting for therapy were also selected. Thirteen OS-related genes were selected and an eight-mRNA model was present to stratify patients into high- and low-risk groups with significantly different survival. CONCLUSIONS: The identified DEGs and biological pathways may provide new perspective on the pathogenesis and treatments of OC. The identified eight-mRNA signature has significant clinical implication for outcome prediction and tailored therapy guidance for OC patients.

PLOD2 increases resistance of gastric cancer cells to 5-fluorouracil by upregulating BCRP and inhibiting apoptosis.

Background: Gastric cancer (GC) is one of the most common cancers, and it is the third most common cause of cancer-related mortality worldwide. Fluorouracil (5-FU)-based chemotherapy is frequently used for the treatment of advanced GC. However, a substantial proportion of patients eventually experience refractory disease due to drug resistance. PLOD2 was reported to increase invasion and migration in several GC cell lines, but the roles of PLOD2 in chemoresistance are still unclear. The present study aimed to determine whether PLOD2 could confer 5-FU resistance in GC. Methods: The expression of PLOD2 in GC cell lines was assessed by Western blotting. The cells were transfected by lentiviral transduction. The IC50 values were determined by the CCK-8 assay. The migration and invasion abilities of cells were analyzed by the Transwell assay. The proportion of apoptotic cells was assessed by flow cytometry. The protein levels of P-gp (MDR1), MRP1, BCRP (ABCG2), Bax and Bcl2 were analyzed by Western blotting. Furthermore, tumor xenograft models in nude mice were established to test tumor growth and weight. Result: The knockdown of PLOD2 in BGC823 cells significantly decreased the IC50 values of 5-FU. It also contributed to reducing the cell migration and invasion and promoting the apoptosis of GC cells. The opposite results appeared in PLOD2-overexpressing MGC803 GC cells. In vivo experiments showed that the knockdown of PLOD2 increased the growth inhibition of transplanted tumors in nude mice in response to 5-FU. Our mechanistic studies revealed that PLOD2-overexpressing cells appear to be resistant to the therapeutic characteristics of 5-FU in GC cells by upregulating BCRP and that PLOD2 confers resistance to 5-FU-induced apoptosis in GC cells by affecting the expression of Bax and Bcl2. Conclusion: PLOD2 contributed to increasing resistance of gastric cancer cells to 5-fluorouracil by upregulating BCRP and inhibiting apoptosis.

Trop2 Promotes Multidrug Resistance by Regulating Notch1 Signaling Pathway in Gastric Cancer Cells.

BACKGROUND Chemotherapy is widely used in gastric cancer treatment, but multidrug resistance remains a leading cause of chemotherapy failure. Trop2 is highly expressed in gastric tumor tissues and greatly influences cancer progression. However, little is known about the relationship between Trop2 and drug resistance in gastric cancer. MATERIAL AND METHODS In the present study, Trop2 was knocked down in BGC823 cells and overexpressed in HGC27. CCK-8 assay was performed to explore the relationship of Trop2 expression and cell proliferation treated with anticancer drugs. Flow cytometry was performed to assess the relationship between Trop2 and cell apoptosis after chemotherapy. Subcutaneous xenograft models were generated to explore the curative effect of DDP to GC in vivo. MRP1 and Notch1 expressions were assessed by Western blot. RESULTS Trop2 decreased cell proliferation inhibition and apoptosis after chemotherapeutic treatments. DDP showed stronger therapeutic effects on Trop2-knockdown tumor than control in vivo. MRP1 and Notch1 signaling pathway were confirmed to participate in Trop2-induced drug resistance. CONCLUSIONS Our findings suggest that Trop2 promotes the resistance of gastric cancer to chemotherapy by activating the Notch1 pathway.

POM121 overexpression is related to a poor prognosis in colorectal cancer.

Background: Nuclear pore membrane protein 121 (POM121) plays a crucial role in nucleocytoplasmic transport, but its significance in tumorigenesis and the progression of colorectal cancer (CRC) remains unknown. The aim of this study was to evaluate the relationship between POM121 and CRC.Methods: POM121 expression in colorectal tissues was analyzed at both the gene and protein levels. We investigated the connection between POM121 expression and clinicopathological features, as well as overall survival. A gene set enrichment analysis (GSEA) was performed, and a protein-protein interaction (PPI) network was constructed to determine the mechanism of POM121 in CRC.Results: CRC tissues displayed a striking increase in POM121 expression compared with colonitis and pericarcinomatous mucosa tissues (66.61% vs 24.36% vs 24.11%, respectively, p < 0.0167). POM121 overexpression was significantly associated with lymph node metastasis, distant metastasis, TNM stage, venous invasion, perineural invasion, preoperative CEA and CA19-9 levels, and Ki67 expression. CRC patients with high POM121 levels tended to have poor overall survival rates. POM121 may participate in the regulation of the cell cycle and DNA repair in CRC.Conclusions: Our results suggest that POM121 has the potential to serve as a novel prognostic biomarker in CRC patients.