A new isoxazolyl-urea derivative induces apoptosis, paraptosis, and ferroptosis by modulating MAPKs in pancreatic cancer cells.

MAPK pathway regulates the major events including cell division, cell death, migration, invasion, and angiogenesis. Small molecules that modulate the MAPK pathway have been demonstrated to impart cytotoxicity in cancer cells. Herein, the synthesis of a new isoxazolyl-urea derivative (QR-4) has been described and its effect on the growth of pancreatic cancer cells has been investigated. QR-4 reduced the cell viability in a panel of pancreatic cancer cells with minimal effect on normal hepatocytes. QR-4 induced the cleavage of PARP and procaspase-3, reduced the expression of antiapoptotic proteins, increased SubG1 cells, and annexin V/PI-stained cells indicating the induction of apoptosis. QR-4 also triggered paraptosis as witnessed by the reduction of mitochondrial membrane potential, decrease in the expression of Alix, increase in the levels of ATF4 and CHOP, and enhanced ER stress. QR-4 also modulated ferroptosis-related events such as elevation in iron levels, alteration in GSH/GSSG ratio, and increase in the expression of TFRC with a parallel decrease in the expression of GPX4 and SLC7A11. The mechanistic approach revealed that QR-4 increases the phosphorylation of all three forms of MAPKs (JNK, p38, and ERK). Independent application of specific inhibitors of these MAPKs resulted in a partial reversal of QR-4-induced effects. Overall, these reports suggest that a new isoxazolyl-urea imparts cell death via apoptosis, paraptosis, and ferroptosis by regulating the MAPK pathway in pancreatic cancer cells.

A new 1,2,3-triazole-indirubin hybrid suppresses tumor growth and pulmonary metastasis by mitigating the HGF/c-MET axis in hepatocellular carcinoma.

INTRODUCTION: Hepatocellular carcinoma (HCC) is a fatal cancer that is often diagnosed at the advanced stages which limits the available therapeutic options. The interaction of HGF with c-MET (a receptor tyrosine kinase) results in the activation of c-MET which subsequently triggers the PI3K/Akt/mTOR axis. Overexpression of c-MET in HCC tissues has been demonstrated to contribute to tumor progression and metastasis. OBJECTIVES: We aimed to synthesize triazole-indirubin conjugates, examine their growth suppressor efficacy in cell-based assays, and investigate the antitumor as well as antimetastatic activity of lead cytotoxic agent in the orthotopic mice model. METHODS: A series of triazole-indirubin hybrids were synthesized and cytotoxicity, apoptogenic, and antimigratory effect of the lead compound (CRI9) was evaluated using MTT assay, cell cycle analysis, annexin-V/PI assay, TUNEL assay, and wound healing assay. The effect of CRI9 on the operation of the HGF/c-MET/PI3K/Akt/mTOR axis was examined using western blotting and transfection experiments. Acute toxicity, antitumor, and antimetastatic activity of CRI9 were examined in NCr nude mice. The expression of c-MET/PI3K/Akt/mTOR, CD31, and Ki-67 was examined using immunohistochemistry and western blotting. RESULTS: Among the new compounds, CRI9 consistently displayed potent cytotoxicity against HGF-induced HCC cells. CRI9 induced apoptosis as evidenced by increased sub G1 cells, annexin-V+/PI+ cells, TUNEL+ cells, and cleavage of procaspase-3 and PARP. CRI9 inhibited HGF-induced phosphorylation of c-METY1234/1235 and subsequently suppressed the PI3K/Akt/mTOR axis. Also, depletion of c-MET or inhibition of c-MET by CRI9 resulted in suppression of the PI3K/Akt/mTOR axis. CRI9 showed no toxic effects in NCr nude mice and displayed a potent antitumor and antimetastatic effect in the orthotopic HCC mice model. CRI9 also reduced the levels of phospho-c-MET, CD31, and Ki-67 and suppressed the activation of the PI3K/Akt/mTOR axis in tumor tissues. CONCLUSION: CRI9 has been identified as a new inhibitor of the c-MET/PI3K/Akt/mTOR axis in HCC preclinical models.

Isoxazolyl-urea derivative evokes apoptosis and paraptosis by abrogating the Wnt/ß-catenin axis in colon cancer cells.

Deregulated activation of the Wnt/ß-catenin pathway is observed in many types of human malignancies including colon cancer. Abrogation of the Wnt/ß-catenin pathway has been demonstrated as an effective way of inducing cancer cell death. Herein, a new isoxazolyl-urea (QR-5) was synthesized and examined its efficacy on the viability of colon cancer cell lines. QR-5 displayed selective cytotoxicity towards colon cancer cells over normal counterparts. QR-5 induced apoptosis as evidenced by elevation in sub-G1 cells, decrease in Bcl-2, MMP-9, COX-2, VEGF and cleavage of PARP and caspase-3. QR-5 reduced the mitochondrial membrane potential, decreased the expression of Alix and elevated the expression of ATF4 and CHOP indicating the induction of paraptosis. The inhibitor of apoptosis (Z-DEVD-FMK) and paraptosis (CHX) could not restore Alix expression and PARP cleavage in QR-5 treated cells, respectively suggesting the complementation between the two cell death pathways. QR-5 suppressed the expression of Wnt/ß-catenin pathway proteins which was also evidenced by the downregulation of nuclear and cytoplasmic ß-catenin. The dependency of QR-5 on ß-catenin for inducing apoptosis and paraptosis was demonstrated by knockdown experiments using ß-catenin specific siRNA. Overall, QR-5 induces apoptosis as well as paraptosis by mitigating the Wnt/ß-catenin axis in colon cancer cells.

A new triazolyl-indolo-quinoxaline induces apoptosis in gastric cancer cells by abrogating the STAT3/5 pathway through upregulation of PTPεC.

Signal transducer and activator of transcription 3 (STAT3) and STAT5 are the transcription factors that have been studied extensively in relevance to the development of cancers in humans. Suppression of either STAT3 or STAT5-mediated signaling events has been demonstrated to be effective in inducing cytotoxicity in cancer cells. Herein, new hybrids of triazolyl-indolo-quinoxaline are synthesized and examined for their effect on the activation of STAT3 and STAT5 pathways in gastric cancer (GC) cells. Among the newly synthesized compounds, 2,3-difluoro-6-((1-(3-fluorophenyl)-1H-1,2,3-triazol-5-yl)methyl)-6H-indolo[2,3-b]quinoxaline (DTI) displayed selective cytotoxicity against GC cells over their normal counterpart. Flow cytometric analysis, annexin-V-fluorescein isothiocyanate staining, terminal deoxynucleotidyl transferase dUTP nick end labeling assay, live and dead assay, and caspase activation experiments suggested DTI as a potent inducer of apoptosis. The mechanistic approach revealed that DTI imparts cytotoxicity via downregulating the phosphorylation of STAT3Y705 and STAT5Y694/699 . DTI significantly reduced the nuclear pool of STAT3/STAT5 and reduced the DNA interaction ability of STAT3/STAT5 as evidenced by immunofluorescence and electrophoretic mobility shift assay. Further investigation revealed that inhibitory effects towards STAT proteins were mediated through the suppression of upstream kinases such as JAK1, JAK2, and Src. Treatment of GC cells with pervanadate counteracted the DTI-driven STAT3/STAT5 inhibition suggesting the involvement of tyrosine phosphatase. Upon DTI exposure, there was a significant upregulation in the mRNA and protein expression of PTPεC, which is a negative regulator of the JAK-STAT pathway. Knockdown of PTPεC suppressed the DTI-induced STATs inhibition in GC cells. Taken together, triazolyl-indolo-quinoxaline is presented as a new inhibitor of the STAT3/STAT5 pathway in GC cells.

A panoramic view on synthetic applications of α-oxothioamides: a highly regioselective synthesis of 2-acyl-4-(het)arylthiazoles and thioethers.

Highly regioselective synthesis of 2-acyl-4-(het)arylthiazoles and thioethers by the reaction between α-oxothioamides and α-bromoketones in the absence of base in DMF and in the presence of triethylamine in acetonitrile, respectively, has been reported. This thiazole synthesis is an important extended work of the Hantzsch thiazole synthesis, which overcomes the drawbacks of earlier reported methods. The probable mechanisms for the formation of thiazoles and thioethers are also presented.