Question

2. Tumor-promoting phorbol esters such as TPA mimic the lipid second messenger diacylglycerol. The tumor promoting effects are most likely due to the suppression of TGF beta signals.

true or false

Answer 1

Ans: False. TGF beta signals induce the tumor promoting effect

soln: Phorbol esters are natural products derived from plants of the family Euphorbiaceae. it show similarities with a serine/threonine protein kinase activity referred to as protein kinase C (PKC). The tumor promoting phorbol esters function as structural mimetics of the second lipid messenger diacylglycerol (DAG) by binding to the C1 domain of DAG receptors.

The TGF-β could induce immune suppression by promoting the formation of T cell-exclusion phenotype tumors which were prone too resistant to ICI treatment. TGF-β pathway broadly inhibits multiple anti-cancer producers including T cell priming and activation, immunosuppressive lymphocyte differentiation, cytotoxic function of effectors and In advanced cancer, it induces tumor progression and metastasis, thus serving as an oncogenic factor.

TGF-β inhibits NK-cell effector functions and in this way contributes to a permissive microenvironment for tumor progression.