A crucial target in drug research is magnifying efficacy and decreasing toxicity. Therefore, using natural active constituents as precursors will enhance both safety and biological activities. Despite having many pharmacological activities, caffeic and ferulic acids showed limited clinical usage due to their poor bioavailability and fast elimination. Therefore, semisynthetic compounds from these two acids were prepared and screened as anticancer agents. In this study, CA and FA showed very potent anticancer activity against Caco-2 cells. Consequently, eighteen derivatives were tested against the same cell line. Four potent candidates were selected for determination of the selectivity index, where compound 10 revealed a high safety margin. Compound 10 represented a new scaffold and showed significant cytotoxic activity against Caco-2. Cell-cycle analysis and evaluation of apoptosis showed that derivatives 10, 7, 11, 15 and 14 showed the highest proportion of cells in a late apoptotic stage.

Despite advances in oncology, the development of targeted agents with reduced resistance profiles remains a critical unmet need. In this study, a novel series of thieno[2,3-d]pyrimidinones was synthesized and evaluated for antiproliferative activity using the National Cancer Institute (NCI) 60-cell line panel. Prescreening at a single dose (10-5 M) identified compound 9d as a potent lead, warranting further evaluation across five concentration levels. Compound 9d exhibited a distinct selectivity towards melanoma, leukemia, and CNS cancer cell lines with pronounced activity against the melanoma panel, MDA-MB-435, SK-MEL-5, and UACC-62. In vivo assessment in a murine B16.F10 melanoma model confirmed significant tumor volume reduction and improved histopathological outcomes. Mechanistic studies revealed that 9d suppresses the BRAF/MEK/ERK signaling pathway by downregulating the oncogenic long non-coding RNA (lncRNA), Actin filament-associated protein 1 antisense RNA 1 (AFAP1-AS1) and modulating the miR-653-5p/RAI14 axis. Additionally, 9d promotes apoptosis via B-cell lymphoma 2 (Bcl-2) downregulation and Caspase-3 activation, collectively these findings establish thieno[2,3d]pyrimidinones, particularly 9d, as promising scaffolds for targeted melanoma therapy and highlights their potential as potent antitumor agents.