Upregulation of T-cadherin suppresses cell proliferation, migration and invasion of gastric cancer in vitro

CRISPR/Cas9 mediated Y-chromosome elimination affects human cells transcriptome

BACKGROUND

Sexual dimorphism represents a key concept in the comprehension of molecular processes guiding several sex-specific physiological and pathological mechanisms. It has been reported that genes involved in many disorders show a sex-dependent expression pattern. Moreover, the loss of Y chromosome (LOY), found to be a physiological age-driven phenomenon, has been linked to many neurodegenerative and autoimmune disorders, and to an increased cancer risk. These findings drove us towards the consideration that LOY may cause the de-regulation of disease specific networks, involving genes located in both autosomal and sex chromosomes.

RESULTS

Exploiting the CRISPR/Cas9 and RNA-sequencing technologies, we generated a Y-deficient human cell line that has been investigated for its gene expression profile. Our results showed that LOY can influence the transcriptome displaying relevant enriched biological processes, such as cell migration regulation, angiogenesis and immune response. Interestingly, the ovarian follicle development pathway was found enriched, supporting the female-mimicking profile of male Y-depleted cells.

CONCLUSION

This study, besides proposing a novel approach to investigate sex-biased physiological and pathological conditions, highlights new roles for the Y chromosome in the sexual dimorphism characterizing human health and diseases. Moreover, this analysis paves the way for the research of new therapeutic approaches for sex dimorphic and LOY-related diseases.

Validation of miR-20a as a Tumor Suppressor Gene in Liver Carcinoma Using Hepatocyte-Specific Hyperactive piggyBac Transposons

We established a semi-high-throughput in vivo screening platform using hyperactive piggyBac (hyPB) transposons (designated as PB-miR) to identify microRNAs (miRs) that inhibit hepatocellular carcinoma (HCC) development in vivo, following miR overexpression in hepatocytes. PB-miRs encoding six different miRs from the miR-17-92 cluster and nine miRs from outside this cluster were transfected into mouse livers that were chemically induced to develop HCC. In this slow-onset HCC model, miR-20a significantly inhibited HCC. Next, we developed a more aggressive HCC model by overexpression of oncogenic Harvey rat sarcoma viral oncogene homolog (HRASG12V) and c-MYC oncogenes that accelerated HCC development after only 6 weeks. The tumor suppressor effect of miR-20a could be demonstrated even in this rapid-onset HRASG12V/c-MYC HCC model, consistent with significantly prolonged survival and decreased HCC tumor burden. Comprehensive RNA expression profiling of 95 selected genes typically associated with HCC development revealed differentially expressed genes and functional pathways that were associated with miR-20a-mediated HCC suppression. To our knowledge, this is the first study establishing a direct causal relationship between miR-20a overexpression and liver cancer inhibition in vivo. Moreover, these results demonstrate that hepatocyte-specific hyPB transposons are an efficient platform to screen and identify miRs that affect overall survival and HCC tumor regression.

Cadherin 13 Inhibits Pancreatic Cancer Progression and Epithelial-mesenchymal Transition by Wnt/β-Catenin Signaling

Cadherin 13 (CDH13) is an atypical cadherin that exerts tumor-suppressive effects on cancers derived from epithelial cells. Although the CDH13 promoter is frequently hypermethylated in pancreatic cancer (PC), the direct impact of CDH13 on PC is unknown. Accordingly, the expression of CDH13 in PC cell lines and paired PC tissues was examined by immunohistochemistry, quantitative real-time PCR and western blotting. Our findings showed that CDH13 was downregulated in PC tissues and cell lines. Moreover, cell proliferation, migration and invasion were detected by CCK-8 assay, transwell migration assay and transwell invasion assay, respectively. Xenograft tumor experiments were used to determine the biological function of CDH13 in vivo. As revealed by our data, CDH13 overexpression significantly inhibited the proliferation, migration and invasion of human PC cells in vitro. The inhibitory effect of CDH13 on PC was further confirmed in animal models. Mice subcutaneously or orthotopically transplanted with CDH13-overexpressing CFPAC-1 cells developed significantly smaller tumors with less liver metastases and mesenteric metastases than those of the control group. Next, transcriptomics and western blot analysis were used to identify the underlying mechanisms. Further molecular mechanism studies showed that CDH13 overexpression inhibited the activation of the Wnt/β-catenin signaling pathway and regulated the expression of epithelial-mesenchymal transition (EMT)-related markers. Our results indicated that CDH13 displayed an inhibitory effect on PC and suggested that CDH13 might be a potential biomarker and a new therapeutic target for PC.

Effect of T-cadherin on the AKT/mTOR signaling pathway, gastric cancer cell cycle, migration and invasion, and its association with patient survival rate

Gastric cancer (GC) is among the most common types of human cancer and is associated with recurrence and metastasis, despite comprehensive surgical and medical treatment. Previous studies observed downregulation of T-cadherin expression in GC tissues, suggesting that this protein may act as an oncosuppressor. The current study investigated the activity of T-cadherin in GC tissues. In a follow-up study of 81 patients with GC, a Kaplan-Meier analysis of overall survival revealed a strong association of T-cadherin overexpression with increased overall survival (P<0.01). Furthermore, stable T-cadherin-overexpressing cell lines were established from HGC-27 cells via transfection of a pcDNA3.1-T-cadherin plasmid and in vitro growth and cell cycle of these cells were measured using MTT and flow cytometry assays, respectively. MTT assays revealed that proliferation of engineered T-cadherin-overexpressing cells was significantly inhibited and flow cytometry demonstrated that T-cadherin overexpression in HGC-27 cells induced cell cycle arrest in the G₀/G₁ phase. Transwell assays demonstrated that T-cadherin-overexpressing HGC-27 cells exhibited reduced invasiveness and metastatic potential. Phosphorylated (p)-protein kinase B (AKT) and p-mammalian target of rapamycin (mTOR) protein levels were reduced in T-cadherin overexpressing HGC-27 cells, suggesting that the AKT/mTOR signaling pathway was involved in the gastric tumor inhibitory effect of T-cadherin. Administration of AKT-activator, insulin-like growth factor-1, to T-cadherin-overexpressing HGC-27 cells significantly affected the proliferation phenotype. In conclusion, the current study provided clinical evidence and revealed a potential mechanism supporting that T-cadherin inhibits gastric tumorigenesis through inhibition of the AKT/mTOR signaling pathway.