Design and Synthesis of Novel 2-Acetamido, 6-Carboxamide Substituted Benzothiazoles as Potential BRAFV600E Inhibitors - In vitro Evaluation of their Antiproliferative Activity.

The oncogenic BRAFV600E kinase leads to abnormal activation of the MAPK signaling pathway and thus, uncontrolled cellular proliferation and cancer development. Based on our previous virtual screening studies which issued 2-acetamido-1,3 benzothiazole-6-carboxamide scaffold as active pharmacophore displaying selectivity against the mutated BRAF, eleven new substituted benzothiazole derivatives were designed and synthesized by coupling of 2-acetamidobenzo[d]thiazole-6-carboxylic acid with the appropriate amines in an effort to provide even more efficient inhibitors and tackle drug resistance often developed during cancer treatment. All derived compounds bore the benzothiazole scaffold substituted at position-2 by an acetamido moiety and at position-6 by a carboxamide functionality, the NH moiety of which was further linked through an alkylene linker to a sulfonamido (or amino) aryl (or alkyl) functionality or a phenylene linker to a sulfonamido aromatic (or non-aromatic) terminal pharmacophore in the order -C6 H4 -NHSO2 -R or reversely -C6 H4 -SO2 N(H)-R. These analogs were subsequently biologically evaluated as potential BRAFV600E inhibitors and antiproliferative agents in several colorectal cancer and melanoma cell lines. In all assays applied, one analog, namely 2-acetamido-N-[3-(pyridin-2-ylamino)propyl]benzo[d]thiazole-6-carboxamide (22), provided promising results in view of its use in drug development.

Noxa upregulation and 5-gene apoptotic biomarker panel in colorectal cancer.

BACKGROUND: NOXA and MCL1 are involved in the intrinsic pathway of apoptosis, where Noxa selectively binds to MCL1 and prevents it from inhibiting apoptosis. Both factors are considered as potential tumour biomarkers, while MCL1 has attracted interest as target in cancer. The purpose of this study was to investigate the expression of NOXA and MCL1 in 160 CRC tumour samples, to investigate their significance, also in combination with IAPs, DR5 expression and KRAS gene mutations in CRC. MATERIALS AND METHODS: Fresh frozen colorectal tissue was obtained from patients undergoing surgery for CRC. Real-time quantitative PCR was performed for the determination of mRNA expression levels. Protein expression was determined immunohistochemically. Differences in the mRNA expression profile were evaluated with the nonparametric Wilcoxon signed ranks test. Statistical analysis was performed with the use of Mann-Whitney U test and receiver-operating characteristic (ROC) curve. RESULTS: NOXA was found to be overexpressed in CRC tumours (P < .0001), even from early stage. Moreover, NOXA/MCL1 mRNA expression was significantly elevated in tumour samples compared to normal pairs (P < .0001). ROC curve analysis showed that both NOXA expression and its combination with Mcl1 expression have fair discriminatory value between CRC and normal colorectal tissue. Combinatorial ROC analysis revealed the most significant discriminatory value of NOXA, MCL1 with cIAP1 and cIAP2 (AUC = 0.834, P < .0001) as a 5-gene panel of markers. CONCLUSION: Noxa, Mcl1, DR5, cIAP1 and cIAP2 mRNA expressions are significantly deregulated in CRC and could provide a panel of markers with significant discriminatory value between CRC and normal colorectal tissue.