Synthesis and Cytotoxicity Assessment against Human Colorectal Cancer Cell Lines of Quaternary 8-Dichloromethyl Protoberberine Alkaloids.

Twenty-two quaternary 8-dichloromethylprotoberberine alkaloids were synthesized from unmodified quaternary protoberberine alkaloids (QPAs) to improve their physical and chemical properties and to obtain selectively anticancer derivatives. The synthesized derivatives showed more appropriate octanol/water partition coefficients by up to values 3-4 compared to unmodified QPA substrates. In addition, these compounds exhibited significant antiproliferative activity against colorectal cancer cells and lower toxicity on normal cells, resulting in more significant selectivity indices than unmodified QPA compounds in vitro. The IC50 values of antiproliferative activity of quaternary 8-dichloromethyl-pseudoberberine 4-chlorobenzenesulfonate and quaternary 8-dichloromethyl-pseudopalmatine methanesulfonate against colorectal cancer cells are 0.31 µM and 0.41 µM, respectively, significantly stronger than those of other compounds and positive control 5-fluorouracil. These findings suggest that 8-dichloromethylation can be used as one of the modification strategies to guide the structural modification and subsequent investigation of anticancer drugs for CRC based on QPAs.

Chemoproteomics Reveals That Quaternary Protoberberine Alkaloids Inhibit Telomerase Activity Oncologically by Binding to PES1.

Natural QPAs have anti-cancer property. The prodrugs of QPAs synthesized in our work with significantly improved solubility showed significantly stronger activity in animal experiments. Nevertheless, the mechanism of action of QPAs for treating cancers remains poorly understood. Here, a chemoproteomic study reveals that QPAs non-covalently and multivalently bind to PES1 in CRC cells, which impinges on the direct interaction between hTERT and hTR in the assembly of the telomerase complex, downregulates telomerase activity, and so promotes the aging process of CRC cells. This study is beneficial for us to conduct extensively the pharmaceutical chemistry research of QPAs.

Targeting ROS-AMPK pathway by multiaction Platinum(IV) prodrugs containing hypolipidemic drug bezafibrate.

Alterations in lipid metabolism, commonly disregarded in the past, have been accepted as a hallmark for cancer. Exploring cancer therapeutics that interrupt the lipid metabolic pathways by monotherapy or combination with conventional chemotherapy or immunotherapy is of great importance. Here we modified cisplatin with an FDA-approved hypolipidemic drug, bezafibrate (BEZ), via the well-established Pt(IV) strategy, affording two multi-functional Pt(IV) anticancer agents cis,cis,trans-[Pt(NH3)2Cl2(BEZ)(OH)] (CB) and cis,cis,trans-[Pt(NH3)2Cl2(BEZ)2] (CP) (BEZ = bezafibrate). The Pt(IV) prodrug CB exhibited an enhanced anticancer activity up to 187-fold greater than the clinical anticancer drug cisplatin. Both CB and CP had less toxicity to normal cells, showing higher efficacies and superior therapeutic indexes than cisplatin. Mechanism studies revealed that the bezafibrate-conjugated Pt(IV) complex CB, as a representative, could massively accumulate in A549 cells and genomic DNA, induce DNA damage, elevate intracellular ROS levels, perturb mitochondrial transmembrane potentials, activate the cellular metabolic sensor AMPK, and result in profound proliferation inhibition and apoptosis. Further cellular data also provided evidence that phosphorylation of AMPK, as a metabolic sensor, could suppress the downstream HMGB1, NF-κB, and VEGFA, which may contribute to the inhibition of angiogenesis and metastasis. Our study suggests that the antitumor action of CB and CP mechanistically distinct from the conventional platinum drugs and that functionalizing platinum-based agents with lipid-modulating agents may represent a novel practical strategy for cancer treatment.