siRNA targeting of Trop2 suppresses the proliferation and invasion of lung adenocarcinoma H460 cells

The Role of Small Interfering RNAs in Hepatocellular Carcinoma

BACKGROUND

Hepatocellular carcinoma (HCC), a primary liver cancer with high mortality, is the most common malignant tumor in the world. Currently, the effect of routine treatment is poor, especially for this kind of cancer with strong heterogeneity and late detection. In the past decades, the researches of gene therapy for HCC based on small interfering RNA have blossomed everywhere. This is a promising therapeutic strategy, but the application of siRNA is limited by the discovery of effective molecular targets and the delivery system targeting HCC. As the deepening of research, scientists have developed many effective delivery systems and found more new therapeutic targets.

CONCLUSIONS

This paper mainly reviews the research on HCC treatment based on siRNA in recent years, and summarizes and classifies the HCC treatment targets and siRNA delivery systems.

Overview of Trop-2 in Cancer: From Pre-Clinical Studies to Future Directions in Clinical Settings

Trophoblast cell surface antigen-2 (Trop-2) is a glycoprotein that was first described as a membrane marker of trophoblast cells and was associated with regenerative abilities. Trop-2 overexpression was also described in several tumour types. Nevertheless, the therapeutic potential of Trop-2 was widely recognized and clinical studies with drug-antibody conjugates have been initiated in various cancer types. Recently, these efforts have been rewarded with the approval of sacituzumab govitecan from both the Food and Drug Administration (FDA) and European Medicines Agency (EMA), for metastatic triple-negative breast cancer patients. In our work, we briefly summarize the various characteristics of cancer cells overexpressing Trop-2, the pre-clinical activities of specific inhibitors, and the role of anti-Trop-2 therapy in current clinical practice. We also review the ongoing clinical trials to provide a snapshot of the future developments of these therapies.

Toxicarioside O Inhibits Cell Proliferation and Epithelial-Mesenchymal Transition by Downregulation of Trop2 in Lung Cancer Cells

Toxicarioside O (TCO), a natural product derived from Antiaris toxicaria, has been identified to be a promising anticancer agent. In this study, we aimed to investigate the effect of TCO on the proliferation and epithelial-mesenchymal transition (EMT) of lung cancer cells and its molecular mechanisms. Here, we indicated that TCO inhibits the proliferation of lung cancer cells both in vitro and in vivo. Our results demonstrated that TCO induces apoptosis in lung cancer cells. Moreover, we found that TCO suppresses EMT program and inhibits cell migration in vitro. Mechanistically, TCO decreases the expression of trophoblast cell surface antigen 2 (Trop2), resulting in inhibition of the PI3K/Akt pathway and EMT program. Overexpression of Trop2 rescues TCO-induced inhibition of cell proliferation and EMT. Our findings demonstrate that TCO markedly inhibits cell proliferation and EMT in lung cancer cells and provides guidance for its drug development.

Knockdown of Trop2 inhibits proliferation and migration and induces apoptosis of endometrial cancer cells via AKT/β-catenin pathway

Endometrial cancer (EC) is the most common gynaecologic malignancy in western countries and has been reported to account for about 7% of female malignant tumours and 20% to 30% of female genital system malignant tumours. Accumulating evidence showed the expression of human trophoblast cell surface antigen 2 (Trop2) was abnormal in many cancers; however, the expression and role of Trop2 in EC are not clear. The Trop-2 protein expression was detected by western blot in EC cells. Cell proliferation, apoptosis, and migration were measured by CCK-8, flow cytometry, and Transwell assay, respectively. The epithelial mesenchymal transition (EMT) and AKT/β-catenin signalling pathway-related proteins in EC cell lines were detected by western blot assay following Trop2 gene silencing. The present study revealed that the Trop2 protein was highly expressed in EC cell lines compared with human endometrial epithelial cells. The Trop2 mRNA and protein were obviously decreased following transfection with Trop2-siRNA sequence in KLE and Ishikawa cells. Meanwhile, Trop2 gene silencing in KLE and Ishikawa cells strongly inhibited cell proliferation and migration and increased cell apoptosis. Investigation into the molecular mechanism indicated that the Trop2 gene silencing suppressed EMT and AKT/β-catenin signalling pathway activation. SIGNIFICANCE OF THE STUDY: These findings suggested that Trop2 silencing inhibited EC cell proliferation and migration and promoted cell apoptosis. The mechanism might be related to the inhibition of the AKT/β-catenin signalling pathway in EC cells. Therefore, Trop2 may be a potential therapeutic target for the treatment of EC.

Antibody-drug conjugates for lung cancer in the era of personalized oncology

With 9.6 million deaths in 2018, cancer represents one of the most common causes of death, both in men and women. Despite recent advances in the understanding of molecular mechanisms involved in cancer development and progression, treatment options are still limited. Limitations of traditional chemotherapy include the lack of selectivity and the unfavorable safety profile. The efficacy of targeted therapies (e.g., tyrosine kinase inhibitors) is also limited by their cytostatic action, which inhibits tumor cell proliferation without inducing tumor cell death, and by the risk of acquired resistance. Antibody-drug conjugates (ADCs), a newly developed class of engineered anticancer drugs, consist of recombinant monoclonal antibodies against tumor-specific antigens that are covalently bound to cytotoxic agents. They have been designed to overcome the limitations of traditional chemotherapy and targeted therapies by combining the target selectivity of monoclonal antibodies with the high potency of cytotoxic drugs. Currently, ADCs that have received regulatory approval include brentuximab vedotin for CD30-positive Hodgkin lymphoma and trastuzumab emtansine for human epidermal growth factor receptor 2-positive breast cancer. However, over 80 novel ADCs are actively being investigated in preclinical studies and early-phase clinical trials. In this review, we will provide a comprehensive overview of the biological rational, efficacy and safety of ADCs as therapeutic agents against non-small cell lung cancer and small cell lung cancer.

Targeting Trop-2 in solid tumors: future prospects

Trop-2 is a transmembrane glycoprotein that is upregulated in all cancer types independent of baseline levels of Trop-2 expression. Trop-2 is an ideal candidate for targeted therapeutics due to it being a transmembrane protein with an extracellular domain overexpressed on a wide variety of tumors as well as its upregulated expression relative to normal cells. As a result, several Trop-2-targeted therapeutics have recently been developed for clinical use, such as anti-Trop-2 antibodies and Trop-2-targeted antibody-drug conjugates (ADC). Subsequently, multiple early-phase clinical trials have demonstrated safety and clinical benefit of Trop-2-based ADCs across multiple tumor types. This includes clinical benefit and tolerability in tumor types with limited treatment options, such as triple-negative breast cancer, platinum-resistant urothelial cancer, and small-cell lung cancer. In this review, we elaborate on all clinical trials involving Trop-2.

Silencing of the TROP2 gene suppresses proliferation and invasion of hepatocellular carcinoma HepG2 cells

Objectives

Overexpression of human trophoblast cell surface antigen 2 (Trop2) has been observed in many cancers; however, its roles in proliferation, apoptosis, migration, and invasion of hepatocellular carcinoma (HCC) remain unclear. Thus, this study aimed to characterize the function of Trop2 in HCC.

Methods

Trop2 protein expression was detected by immunohistochemistry in HCC tissues. Cell proliferation, apoptosis, and invasion were respectively measured by CCK-8, flow cytometry, Transwell, and wound healing assays. Expression levels of epithelial–mesenchymal transition-related proteins and Trop2 protein in HCC cell lines were detected by western blotting after silencing of the TROP2 gene.

Results

Trop2 protein was highly expressed in HCC tissues and HCC cell lines. Trop2 mRNA and protein expression levels decreased in HepG2 and HCCLM3 cells after transfection with Trop2 siRNA. Silencing of the TROP2 gene in HepG2 and HCCLM3 cells strongly inhibited cell proliferation and migration, while enhancing cell apoptosis. Investigation of the molecular mechanism revealed that silencing of the TROP2 gene suppressed epithelial–mesenchymal transition of HepG2 and HCCLM3 cells.

Conclusions

The results of the present study may improve understanding of the role of Trop2 in regulation of cell proliferation and invasion, and may aid in development of novel therapy for HCC.

The emergence of trophoblast cell-surface antigen 2 (TROP-2) as a novel cancer target

TROP-2 is a glycoprotein first described as a surface marker of trophoblast cells, but subsequently shown to be increased in many solid cancers, with lower expression in certain normal tissues. It regulates cancer growth, invasion and spread by several signaling pathways, and has a role in stem cell biology and other diseases. This review summarizes TROP-2's properties, especially in cancer, and particularly its role as a target for antibody-drug conjugates (ADC) or immunotherapy. When the irinotecan metabolite, SN-38, is conjugated to a humanized anti-TROP-2 antibody (sacituzumab govitecan), it shows potent broad anticancer activity in human cancer xenografts and in patients with advanced triple-negative breast, non-small cell and small-cell lung, as well as urothelial cancers.

Trop2 promotes proliferation, invasion and EMT of nasopharyngeal carcinoma cells through the NF-κB pathway

Human trophoblast cell surface antigen 2 (Trop2), a cell surface transmembrane glycoprotein receptor, has been demonstrated to be closely associated with increasing tumor aggressiveness, metastasis and unfavorable prognosis.