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Targeting the Trp-Kyn pathway is an attractive approach for cancer immunotherapy. Thioredoxin reductase (TrxR) enzymes are reactive oxygen species (ROS) modulators that are involved in the tumor cell growth and survival processes. The 4-phenylimidazole scaffold is well-established as useful for indoleamine 2,3-dioxygenase 1 (IDO1) inhibition, while piperlongumine (PL) and its derivatives have been reported to be inhibitors of TrxR. To take advantage of both immunotherapy and TrxR inhibition, we designed a first-generation dual IDO1 and TrxR inhibitor (ZC0101) using the structural combination of 4-phenylimidazole and PL scaffolds. ZC0101 exhibited better dual inhibition against IDO1 and TrxR in vitro and in cell enzyme assays than the uncombined forms of 4-phenylimidazole and PL. It also showed antiproliferative activity in various cancer cell lines, and a selective killing effect between normal and cancer cells. Furthermore, ZC0101 effectively induced apoptosis and ROS accumulation in cancer cells. Knockdown of TrxR1 and IDO1 expression induced cellular enzyme inhibition and ROS accumulation effects during ZC0101 treatment, but only reduced TrxR1 expression was able to improve ZC0101's antiproliferation effect. This proof-of-concept study provides a novel strategy for cancer treatment. ZC0101 represents a promising lead compound for the development of novel antitumor agents that can also be used as a valuable probe to clarify the relationships and mechanisms of cancer immunotherapy and ROS modulators.

With the aim of discovering novel cyclin-dependent kinase 8 (CDK8) inhibitors, a combined similarity search and molecular docking approach was employed, which led to 32 hits. Biological tests led to the discovery of several novel submicromolar inhibitors. In particular, compound C768-0769 (ZC0201) showed good CDK8 inhibitory activity, and compound ZC0201 effectively suppressed HCT-116 colorectal cancer cell proliferation by inducing G1/S transition arrest. Furthermore, modulation of phosphorylated signal transducer and activator of transcription 1 (Ser 727) (STAT1SER727), a pharmacodynamic biomarker of CDK8 activity, demonstrated that ZC0201 may cause G1/S transition arrest through CDK8 activity inhibition. Due to its good cellular activity, ZC0201 may be an ideal lead compound for further modification as a potential cancer therapeutic agent.

Multidrug resistance (MDR) is a major concern when using chemotherapy for the treatment of patients with colorectal cancer. MDR modulators are agents that can reverse MDR and, thus, enhance the chemosensitivity of tumor cells. The development of MDR modulators can improve the therapeutic efficacies of MDR in cancer. However, few effective MDR modulators have been identified so far. Curcumin has been reported to be an effective compound in the reversal of MDR in colorectal cancer cells. However, the mechanisms associated with the reversal effect of curcumin on MDR and its regulation of target factors in MDR cells remain to be fully elucidated. 3-(4,5-dimethyl-2-thiazol)-2,5-diphenyltetrazolium bromide assays, flow cytometer apoptosis assays as well as mRNA and protein expression assays were performed in the present study, and the results confirmed the reversal effect of curcumin on HCT-8/5-Fu cells and provided evidence that activated nuclear factor erythroid 2-related factor (Nrf2) deficiency induced by the curcumin altered the B-cell lymphoma 2 (Bcl-2) associated X protein/Bcl-2 expression ratio, which led to the induction of apoptosis in HCT-8/5-Fu cells. These results indicated that Nrf2 may have a functional in the reversal effect of curcumin and contribute, at least in part, to the outcomes of chemotherapy in patients with MDR.

Adenomyosis is a specific subtype of endometriosis and recent evidences have indicated that Tanshinone IIA (TSIIA) might be a potential therapeutic option for endometriosis. Meanwhile, endometrial stromal cells (ESCs) of adenomyosis might play crucial roles in the progression of this disease, emphasizing the importance of targeting ESCs in the treatment of adenomyosis. Furthermore, previous evidences also implicated that deregulated 14-3-3ζ expression might be associated with therapeutic effects of certain drugs. The aim of this study is to evaluate the potential involvement of 14-3-3ζ in the process of TSIIA-treated adenomyosis. Ectopic endometrial stromal cells (EESCs) were isolated from a total of 3 patients with adenomyosis. Cells were treated with TSIIA and infected with 14-3-3ζ-overexpressing adenovirus, the expression level of 14-3-3ζ was determined by western blotting (WB), cell viability was detected by Cell Counting Kit-8 (CCK8), cell invasion and migration was evaluated by transwell assay, and cell apoptosis was detected by flow cytometry. TSIIA could decrease cell viability, induce cell apoptosis, and inhibit cell migration and invasion in EESCs. Mechanistically, TSIIA markedly reduced the expression of 14-3-3ζ in EESCs, and overexpression of 14-3-3ζ could restore the ability of cell viability, migration and invasion, but has no effect on cell apoptosis. TSIIA could be a promising novel therapeutic agent for adenomyosis, via inducing cell apoptosis, inhibiting cell viability, migration and invasion in EESCs. Furthermore, the effects of cell viability, migration and invasion were mediated in 14-3-3ζ-dependent manner while that of cell apoptosis was mediated in 14-3-3ζ-independent manner.