Research Projects

Liver cancer is one of the fatal malignancies that ranked third in terms of cancer-related mortality globally (757,948 deaths) in 2022. Hepatocellular carcinoma (HCC) is an aggressive type of liver cancer that accounts for about 90% of total liver malignancies. According to the American Cancer Society, the 5-year relative survival rate of liver cancer patients is as low as 22%. Although 5-year survival rates depend on the tumor stage, about 80% of patients with HCC are diagnosed at the advanced stages in which the majority of the existing first-line chemotherapeutic agents (sorafenib or lenvatinib) display limited efficacy. Many studies are being undertaken either to discover new therapeutic agents or to develop small molecules that can enhance the efficacy of first-line therapeutic agents. STAT3 is a transcription factor that is involved in the expression of genes involved in driving cell growth, apoptotic resistance, prosurvival, and metastasis—the interaction of IL-6 family cytokines with their corresponding receptors results in the activation of cytosolic JAKs. The activated JAKs phosphorylate STAT3 which undergoes dimerization with another phosphorylated monomer and is subsequently transported into the nucleus where the STAT3 dimer interacts with a specific DNA consensus to impart growth-promoting functions. Unfortunately, STAT3 is hyperactivated in various types of malignancies including HCC which leads to the elevated expression of genes responsible for oncogenesis and tumor progression. Targeting STAT3 by small molecules has been proven effective in imparting antitumor effects. Fedratinib and Ruxolitinib are the FDA-approved drugs for the treatment of myeloproliferative diseases. They interfere with the functions of STAT3 by blocking the catalytic activity of JAKs. Many JAK/STAT3 inhibitors are undergoing clinical trials for cancer treatment. Many studies have shown the hyperactivation of STAT3 in HCC cells as well as tumor tissues of HCC patients suggesting that STAT3 inhibition is a good strategy to get a good clinical outcome. The derivatives of either pyrrolidine or isoxazole have demonstrated good antitumor activity. Therefore, the present study proposes the synthesis of a library of pyrrolidine-isoxazole hybrids and screen their cytotoxic potential using an MTT assay. Among the new compounds, one lead cytotoxic agent will be identified and further tested using flow cytometric analysis, annexin V assay, and TUNEL assay. The inhibitory efficacy of lead agent towards the STAT3 pathway will be examined by analyzing the expression of phospho-JAK/Src/STAT3 and downstream proteins. Also, immunocytochemistry for STAT3 localization, electrophoretic mobility shift assay for DNA binding, and transfection with STAT3-siRNA to assess the specificity of lead agent towards the STAT3 pathway will be performed. The in vivo acute toxicity and antitumor effect of the lead compound will be assessed in an orthotopic HCC nude mice model.