Insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) is a multifunctional RNA-binding protein with an oncofetal pattern of expression shown to be implicated in the development of a variety of malignancies. In this study, we explored the role and mechanisms of IGF2BP1 in melanoma development and progression. In two different in vivo models, we showed that while genetic deletion or shRNA-mediated suppression of IGF2BP1 did not affect primary tumor formation, it drastically suppressed lung metastasis. Here we demonstrated that extracellular vesicles (EVs) secreted by melanoma cells mediate the effects of IGF2BP1 on metastasis: EVs from the IGF2BP1 knockdown melanoma cells failed to promote metastasis whereas EVs isolated from IGF2BP1-overexpressed melanoma cells further accelerated EV-induced metastasis. Moreover, the EVs from IGF2BP1 knockdown melanoma cells inhibited fibronectin deposition and accumulation of CD45 + cells in the lungs compared to control EVs, thus blocking the pre-metastatic niche formation potential of EVs. IGF2BP1 knockdown did not affect size, number, or protein/RNA concentration of secreted EVs or their uptake by recipient cells in vitro or in vivo . However, RNA-sequencing and proteomics analysis of the EVs revealed differential expression in a number of mRNA, proteins and miRNAs. This suggested that IGF2BP1 is intimately involved in the regulation of the cargo of EVs, thereby affecting the pro-metastatic function of melanoma-derived EVs. To the best of our knowledge, this is the first study that demonstrates the role of RNA-binding protein IGF2BP1 in EV-mediated promotion of melanoma metastasis and may provide novel avenues for the development of metastatic inhibitors.

Zinc deficiency is linked to poor prognosis in COVID-19 patients while clinical trials with Zinc demonstrate better clinical outcome. The molecular target and mechanistic details of anti-coronaviral activity of Zinc...

The gap junction (GJ) protein connexin-43 (Cx43) is considered as a tumour suppressor protein for its role in reversing the phenotype of the cancer cells. In this study, we exploited the antitumor property of Cx43 in conjunction with the artesunate (ART), a plant-based active anti-malarial compound. The reactive oxygen species (ROS) generated by ART resulted in DNA damage, which in turn led to DNA damage response by activation of DNA damage repair proteins. GJ deficient MCF-7 cells transfected with Cx43 gene showed an increased sensitivity towards dose-dependent ART treatment and required a significantly lower dose of ART to attain its IC50, as compared to parental cells. This would ultimately result in reduced dose-dependent side effects of ART. The Co-culture experiments involving GJ intercellular communication (GJIC) deficient and GJIC enabled cells, established the transfer of ROS to the neighbouring cancer cells not exposed to ART. The ROS accumulated in the ART-treated cells induced the oxidative damage in neighbouring cells, leading to bystander cell death and inhibition of bystander cell proliferation. Thus, our study revealed that expression of Cx43 helped in reducing the dose-dependent cytotoxicity of ART as well as enhanced the bystander apoptosis of the neighbouring cells.

Secreted frizzled-related proteins (sFRPs) constitute a family of proteins, which impede the Wnt signaling pathway. Upregulation of the Wnt cascade is one of the multiple facets of carcinogenesis. Herein, we report the expression, solubilization, purification, characterization, and anti-cell proliferative activity of a novel recombinant GST-tagged sFRP1 of human origin. sFRP1 was cloned into pGEX-4T2 bacterial expression vector, and the recombinant protein was overexpressed in Escherichia coli BL21 (DE3). It was solubilized from inclusion bodies with N-lauroylsarcosine and Triton X-100, before being purified to homogeneity using glutathione agarose affinity chromatography column. The purified protein was characterized using Western blotting, MALDI TOF-TOF, and circular dichroism spectroscopy analysis. Homology modeling and docking studies revealed that tagging GST with sFRP1 does not change the binding conformation of the cysteine-rich domain and hence, possibly does not alter its function. The novel anti-proliferative activity of GST-sFRP1 was demonstrated in a dose-dependent manner on two cancer cell lines, viz., HeLa (cervical cancer) and MCF-7 (breast cancer). Also, combination therapy of the protein with chemotherapeutic drugs resulted in enhanced anti-cancer activity. This opens up a new avenue in the application of recombinant sFRP1 for cancer therapeutics.