Bidirectional regulation between AP-1 and SUMOylation pathway genes modulates inflammatory signaling during Salmonella infection.

Post-translational modifications (PTMs), such as SUMOylation, are known to modulate fundamental processes of a cell. Infectious agents such as Salmonella Typhimurium (STm), which causes gastroenteritis, utilize the PTM mechanism SUMOylation to hijack the host cell. STm suppresses host SUMO pathway genes UBC9 (also known as UBE2I) and PIAS1 to perturb SUMOylation for an efficient infection. In the present study, the regulation of SUMO pathway genes during STm infection was investigated. A direct binding of c-Fos (encoded by FOS), a component of activator protein-1 (AP-1), to promoters of both UBC9 and PIAS1 was observed. Experimental perturbation of c-Fos led to changes in the expression of both UBC9 and PIAS1. STm infection of fibroblasts with SUMOylation-deficient c-Fos (c-FOS-KOSUMO-def-FOS) resulted in uncontrolled activation of target genes, leading to massive immune activation. Infection of c-FOS-KOSUMO-def-FOS cells favored STm replication, indicating misdirected immune mechanisms. Finally, chromatin immunoprecipitation assays confirmed a context-dependent differential binding and release of AP-1 to and from target genes due to its phosphorylation and SUMOylation, respectively. Overall, our data point towards the existence of a bidirectional cross-talk between c-Fos and the SUMO pathway and highlight their importance in AP-1 function in STm infection and beyond. This article has an associated First Person interview with the first author of the paper.

Invitro Evaluation of Torin2 and 2, 6-Dihydroxyacetophenone in Colorectal Cancer Therapy.

Colorectal cancer (CRC) is one of the most prevalent cancers diagnosed worldwide. Despite recent advances, resistance to cytotoxic and targeted therapy remains one of the greatest challenges in long-term management of colorectal cancer therapy. Recently established role of mTOR signaling in proliferation of CRC has incited for evaluation of mTOR kinase specific inhibitors in CRC therapy. Second generation mTOR kinase inhibitors including Torin2 has demonstrated efficient anticancer properties against variety of cancers and are in various stages of drug development. The time and financial constraints concomitant from discovery to development of efficient chemical inhibitors has redirected attention towards investigation of wide spread naturally occurring largely inexpensive compounds for their therapeutic potential. One such naturally occurring compound acetophenone derivative polyphenolic compound 2, 6-Dihydroxyacetophenone (DHAP) inhibits cell growth in different conditions. We investigated anticancer properties of both Torin2 and DHAP against colorectal cancer in HCT8 cell lines. Both Torin2 and DHAP inhibited growth of CRC cells at different concentrations by restricting multiple cellular functions e.g., cell cycle progression, cell migration and induced apoptosis. Treatment of HCT8 cells with natural compound DHAP resulted in reduced expression of mTOR pathway specific genes p70S6K1 and AKT1. In silico docking studies showed affinity of DHAP to mTOR kinase like Torin2. Taken together, our result vouches for role of Torin2 in CRC therapy and recommends DHAP an mTOR inhibitor, as a potential lead in the development of new therapeutic regimes against colorectal cancer.