7-Ethyl-10-hydroxycamptothecin (SN38) and vorinostat (SAHA) are quite promising combination therapy agents applied to the clinical treatment of cancer. In this study, we designed and synthesized a series of novel SN38-SAHA co-prodrugs, which were conjugated by four different amino acids including glycine, alanine, aminobutyric acid, and 6-aminocaproic acid. The hydrolytic reconversion rate to SN38 and SAHA critically depended on the carbon chain length, which were evaluated in PBS (pH 6.0/7.4) and plasma (human/mouse). With decreasing amino acid chain length, the hydrolytic reconversion rate increased gradually. The in vitro cytotoxicity test was evaluated by the sulforhodamine B (SRB) assay on the human lung adenocarcinoma cell line A549 and human colorectal cancer cell line HCT116. With the evaluation of stability and in vitro cytotoxicity, an appropriate linker was found, and the active drug can be released efficiently from compound 3a, which exhibited strong antiproliferative activity in A549 and HCT-116 cell lines correspondingly. These results indicated that the well-designed co-prodrug 3a and this kind of strategy can be a promising approach for anticancer therapy.

In this study, we developed the maleimidiation of dextran and applied it in a camptothecin drug delivery system.

Thieno[3,2-d]pyrimidine as an effective pharmacophore has been extensively studied. However, its 2,6-substituted derivatives are rarely reported. In the present study, eighteen 2,6-substituted thieno[3,2-d]pyrimidine derivatives containing electrophilic warheads were designed based on the first known Fibroblast growth factor receptor-4 (FGFR4) inhibitor Blu9931. Unexpectedly, all of the derivatives exhibited negligible activity against FGFR4. However, most of the target compounds exhibited antiproliferative activities against four human cancer cell lines, including A431, NCI-H1975, Ramos and SNU-16. Compound 12 showed the most potent antiproliferative activities on the above four cell lines with IC₅₀ values of 1.4 μM, 1.2 μM, 0.6 μM, and 2.6 μM, respectively. Additionally, the antiproliferative activity of 12 against MDA-MB-221 proved that 12 had the selectivity towards certain tumor cell lines. Furthermore, preliminary structure-activity relationship analysis was discussed based on the experimental data.