ABSTRACT
Cytotoxic effects of (R)-4'-methylklavuzon were investigated on hepatocellular carcinoma cells (HuH-7 and HepG2) and HuH-7 EpCAM+/CD133+ cancer stem cells. IC50 of (R)-4'-methylklavuzon was found as 1.25⯵M for HuH-7 parental cells while it was found as 2.50⯵M for HuH-7 EpCAM+/CD133+ cancer stem cells. (R)-4'-methylklavuzon tended to show more efficient in vitro cytotoxicity with its lower IC50 values on hepatocellular carcinoma cell lines compared to its lead molecule, goniothalamin and FDA-approved drugs, sorafenib and regorafenib. Cell-based Sirtuin/HDAC enzyme activity measurements revealed that endogenous Sirtuin/HDAC enzymes were reduced by 40% compared to control. SIRT1 protein levels were upregulated indicating triggered DNA repair mechanism. p53 was overexpressed in HepG2 cells. (R)-4'-methylklavuzon inhibited CRM1 protein providing increased retention of p53 and RIOK2 protein in the nucleus. HuH-7 parental and EpCAM+/CD133+ cancer stem cell spheroids lost intact morphology. 3D HepG2 spheroid viabilities were decreased in a correlation with upregulation in p53 protein levels.
Subject(s)
AC133 Antigen/antagonists & inhibitors , Antineoplastic Agents/pharmacology , Carcinoma, Hepatocellular/drug therapy , Epithelial Cell Adhesion Molecule/antagonists & inhibitors , Karyopherins/antagonists & inhibitors , Liver Neoplasms/drug therapy , Naphthalenes/pharmacology , Receptors, Cytoplasmic and Nuclear/antagonists & inhibitors , Sirtuin 1/antagonists & inhibitors , AC133 Antigen/metabolism , Antineoplastic Agents/chemical synthesis , Antineoplastic Agents/chemistry , Carcinoma, Hepatocellular/metabolism , Carcinoma, Hepatocellular/pathology , Cell Proliferation/drug effects , Cell Survival/drug effects , Dose-Response Relationship, Drug , Drug Screening Assays, Antitumor , Epithelial Cell Adhesion Molecule/metabolism , Hep G2 Cells , Humans , Karyopherins/metabolism , Liver Neoplasms/metabolism , Liver Neoplasms/pathology , Molecular Structure , Naphthalenes/chemical synthesis , Naphthalenes/chemistry , Receptors, Cytoplasmic and Nuclear/metabolism , Sirtuin 1/metabolism , Structure-Activity Relationship , Tumor Cells, Cultured , Exportin 1 ProteinABSTRACT
Klavuzons are 6-(naphthalen-1-yl) substituted 5,6-dihydro-2H-pyran-2-one derivatives showing promising antiproliferative activities in variety of cancer cell lines. In this work, racemic syntheses of nine novel 4'-alkyl substituted klavuzon derivatives were completed in eight steps and anticancer properties of these compounds were evaluated. It is found that size of the substituent has dramatic effect over the potency and selectivity of the cytotoxic activity in cancerous and healthy pancreatic cell lines. The size of the substituent can also effect the CRM1 inhibitory properties of klavuzon derivatives. Strong cytotoxic activity and CRM1 inhibition can be observed only when a small substituent present at 4'-position of naphthalen-1-yl group. However, these substituents makes the molecule more cytotoxic in healthy pancreatic cells rather than cancerous pancreatic cells. Among the tested compounds 1,2,3,4-tetrahydrophenanthren-9-yl substituted lactone was the most cytotoxic compound and its antiproliferative activity was also tested in 3D spheroids generated from HuH-7 cell lines.
