Tumor-associated macrophages promoting PD-L1 expression in infiltrating B cells through the CXCL12/CXCR4 axis in human hepatocellular carcinoma.

The inflammation-related tumor microenvironment (TME) is one of the major driving forces of hepatocarcinogenesis. We aimed to investigate cell-to-cell communication among Hepatocellular Carcinoma (HCC) through re-analyzing HCC single-cell RNA-seq data, and to confirm such cellular interaction through in vitro and in vivo study. We found a subset of Regulatory B cells with PD-L1 expression (PD-L1+ Bregs), mainly located in adjacent HCC tissues. In co-localization with PD-L1+ Bregs, a subset of Tumor Associated Macrophages with high expression of CXCL12 (CXCL12+ TAMs) was also mainly located in adjacent HCC tissues. Moreover, CXCL12+ TAMs can be stimulated in vitro using an HCC conditional medium. Using CellChat analysis and Multiplex Immunohistochemistry staining (mIHC), CXCL12+ TAMs were found to be first recruited by Cancer-Associated Fibroblasts (CAFs) through a CD74/macrophage migration inhibitory factor (MIF) pattern, and further differentiated into TGF-ß-enriched tissues. Furthermore, CXCL12+ TAMs recruited PD-L1+ Bregs via the CXCL12/CXCR4 axis, and CXCR4 expression was significantly positively correlated to PD-L1 expression in PD-L1+ Bregs. At last, we confirmed the communications among CAFs, Macrophages and B cells and their tumor-promoting effects by using an orthotopic mouse model of HCC. Immunosuppressive HCC TME involving cell-to-cell communications comprised MIF-secreting CAFs, CXCL12-secreting TAMs, and PD-L1-producing Bregs, and their regulation could be promising therapeutic targets in future immunotherapy for human HCC.

Macrophage-secreted Exosomes Delivering miRNA-21 Inhibitor can Regulate BGC-823 Cell Proliferation.

Exosomes, membranous nanovesicles, naturally carry bio-macromolecules or miRNA and play impoetant roles in tumor pathogenesis. Here, we showed that macrophages cell-derived exosomes can function as vehicles to deliver exogenous miR-21 inhibitor into BGC-823 gastric cancer cells. Exosomes loaded with miR-21 inhibitor significantly increased miR-21 levels in BGC-823, but miR-21 inhibitor loaded in exosomes exerted an opposite effect. miRNA transfected with exosomes had less cellular toxicity to host cells compared to conventional transfection methods. The miR-21 inhibitor loaded exosomes promoted the migration ability and reduced apoptosis of BGC-823 gastric cancer cells. These observations indicate that miR-21 acts as a tumor promoter by targeting the PDCD4 gene and preventing apoptosis of gastric cancer cells through inhibition of PDCD4 expression. Furthermore, exosome -mediated miR-21 inhibitor delivery resulted in functionally more efficient inhibition and less cellular toxicity compared to conventional transfection methods. Similar approaches could be useful in modification of target biomolecules in vitro and in vivo. These findings contribute to our understanding of the functions of miR-21 and exosomes as a carrier for therapy of gastric cancer.

Anti-miR-362-3p Inhibits Migration and Invasion of Human Gastric Cancer Cells by Its Target CD82.

AIM: This study was to investigate the effects and mechanisms of miR-362-3p on regulation of gastric cancer (GC) cell metastasis potential. METHODS: We detected miR-362-3p level in GC and adjacent normal tissues and investigated the relationship with clinicopathological factors. Next, we analyzed the level of miR-362-3p expression and CD82 in different differentiated GC cells compared with a normal gastric mucosa cell by RT-PCR and Western blot. Dual-luciferase reporter assay and Western blot confirmed a direct interaction between miR-362-3p and CD82 3'UTR. After miR-362-3p and CD82 were silenced in GC cells, we compared the transfected GC cells migration and invasion capacity by transwell assay. In addition, we detected the effects on cells angiogenesis by tube formation assay. Western blot was used to detect the impact of CD82 and miR-362-3p on epithelial-to-mesenchymal transition markers in treated GC cells. RESULTS: Level of miR-362-3p expression was much higher in GC cells than in normal gastric mucosa cell, and miR-362-3p expression negatively correlated with CD82 mRNA expression in these cell lines. Furthermore, miR-362-3p expression induced [corrected] GC cell metastasis capacity by suppression of CD82 expression. Level of miR-362-3p may mediate E-cadherin, N-cadherin, and vimentin expression in GC cells. CONCLUSION: This study illuminated that downregulation of miR-362-3p along with the upregulation of CD82 in GC cells resulted in the inhibition of GC migration and invasion. Thus, our results suggested that miR-362-3p or CD82 can be exploited as a new potential target for control of GC in the future.

MiR-421 regulates apoptosis of BGC-823 gastric cancer cells by targeting caspase-3.

MicroRNAs might act as oncogenes or tumor suppressors in cancer. Recent studies have shown that miR-421 is up-regulated in human gastric cancer. Here, we found that miR-421 was over-expressed in gastric cancer tissues and cell lines. Bioinformatics analysis predicted that the caspase-3 gene was a target of miR-421. Caspase-3 was negatively regulated by miR-421 at the post-transcriptional level. Bax and Bcl-2 were also regulated by miR-421. Moreover, tumor necrosis factor receptor-I and -II, death receptors in the apoptosis pathway, were up-regulated by miR-421. The over-expression of miR-421 promoted gastric cancer cell growth and inhibited apoptosis of the BGC-823 gastric cancer cell line. These observations indicate that miR-421 acts as a tumor promoter by targeting the caspase-3 gene and preventing apoptosis of gastric cancer cells through inhibition of caspase-3 expression. These findings contribute to our understanding of the functions of miR-421 in gastric cancer.

Proliferation of colorectal cancer is promoted by two signaling transduction expression patterns: ErbB2/ErbB3/AKT and MET/ErbB3/MAPK.

One of the recent breakthroughs in cancer research is the identification of activating mutations in various receptor tyrosine kinase(RTK) pathways in many cancers including colorectal cancer(CRC). We hypothesize that, alternative to mutations, overexpression of various oncogenic RTKs may also underpin CRC pathogenesis, and different RTK may couple with distinct downstream signaling pathways in different subtypes of human CRC. By immunohistochemistry, we show here that RTK members ErbB2, ErbB3 and c-Met were in deed differentially overexpressed in colorectal cancer patient samples leading to constitutive activation of RTK signaling pathways. Using ErbB2 specific inhibitor Lapatinib and c-Met specific inhibitor PHA-665752, we further demonstrated that this constitutive activation of RTK signaling is necessary for the survival of colorectal cancer cells. Furthermore, we show that RTK overexpression pattern dictates the use of downstream AKT and/or MAPK pathways. Our data are important additions to current oncogenic mutation models, and further explain the clinical variation in therapeutic responses of colorectal cancer. Our findings advocate for more personalized therapy tailored to individual patients based on their type of RTK expression in addition to their mutation status.

Effects of microRNA-106 on proliferation of gastric cancer cell through regulating p21 and E2F5.

OBJECTIVE: To investigate the effects of miR-106b on malignant characteristics of gastric cancer cells, and explore possible mechanisms. METHODS: Expression of miR-106b, p21 and E2F was determined by real-time PCR. Transfection with miR-106b mimics was conducted, and gastric cancer cells with miR-106b overexpression were obtained. Cells transfected with mimic mutants and those without transfection served as negative and blank controls, respectively. Flow cytometry and transwell assays were adopted to detect the effects of miR-106b overexpression on cell cycle, migration and invasion of gastric cancer cells. RESULTS: . The expression of miR- 106b in gastric cancer cells was significantly higher than that in normal gastric mucosa cells. Furthermore, the expression level of miR-106b rose according to the degree of malignacy among the three GC cell strains (MKN- 45 > SGC-7901 > MKN-28). Overexpression of miR-106b shortened the G0/G1 phase and accelerated cell cycle progression, while reducing p21 and E2F5, without any significant effects on the capacity for migration and invasion of gastric cancer cells. CONCLUSIONS: miR-106b may promote cell cycling of gastric cancer cells through regulation of p21 and E2F5 target gene expression.

Association of the PSCA rs2294008 C>T polymorphism with gastric cancer risk: evidence from a meta-analysis.

BACKGROUND: Multiple studies have reported associations between the PSCA rs2294008 C>T polymorphism and GC, but susceptibility has proven inconsistent. Therefore, we estimates the relationship between the rs2294008 C>T polymorphism and GC by meta-analysis. METHODS: PubMed, Embase and Web of Science databases were searched and nine independent case-control studies were included in this meta- analysis. Crude ORs with 95% CIs were extracted according to the Mantal-Haenszel method and pooled to assess the strength of the association. RESULTS: We observed that the PSCA rs2294008 C>T polymorphism was significantly correlated with GC risk when all studies were pooled into the meta-analysis. Further subgroup analysis showed the polymorphism to be linked with diffuse and noncardia GC in the allele contrast model, homozygote codominant model, dominant model, and recessive model. However, no connection was apparent for intestinal and cardia GC. In the stratified analysis by ethnicity, significant associations were observed in Asians for the recessive model. Interestingly, the relationship was particularly significant in the Chinese population. CONCLUSIONS: Our findings suggest that the PSCA rs2294008 C>T polymorphism is a risk factor for GC, especially in diffuse and noncardia GC and in Chinese.

[Determination of circulating HBV specific CD8+ T cells in hepatitis B patients by flow cytometry and its clinical significance].

OBJECTIVE: To explore the levels of circulating HBV specific CD8+ T cells in hepatitis B patients and analysis its clinical significance. METHODS: HBV specific CD8+ T cells in whole blood samples of twenty-five acute hepatitis B patients, thirty-five chronic hepatitis B patients and ten healthy control were stained with pentamers complex of HLA-A2 and HBV core 18-27 peptide and counted by flow cytometry. RESULTS: The medians of HBV core 18-27 specific CD8+ T cells quantities among total CD8+ cells were 2.93% (1.12% -0.63%) in 12 HLA-A2+ acute hepatitis B patients and 0.75% (< 0.01% - 1.76%) in 16 HLA-A2+ chronic hepatitis B patients respectively. There was showed a marked significant between the two groups (P < 0.01). The medians of HBV core 18-27 specific CD8+ T cells of 10 HLA-A2+ healthy control, 13 HLA-A2- acute hepatitis B patients and 19 HLA-A2- chronic hepatitis B patients were all lower than 0.02% separately. CONCLUSION: HLA-peptides pentamers staining flow cytometry is a direct ex vivo method to detect the levels of circulating HBV specific CD8+ T cells which may be play a crucial role in complete clearance of HBV and relates to clinical consequence in hepatitis B patients.