Anthranilamide-Pyrazolo[1,5-a]pyrimidine Conjugates as p53 Activators in Cervical Cancer Cells

• Published in: ChemMedChem 2012-08, Vol.7 (8), p.1453-1464
• Main Authors: Kamal, Ahmed, Tamboli, Jaki R., Ramaiah, M. Janaki, Adil, S. F., Koteswara Rao, G., Viswanath, A., Mallareddy, Adla, Pushpavalli, S. N. C. V. L., Pal-Bhadra, Manika
• Format: Article
• Language: English
• Subjects: Antineoplastic Agents - chemical synthesis; Antineoplastic Agents - chemistry; Antineoplastic Agents - toxicity; antitumor agents; Apoptosis; Apoptosis - drug effects; bcl-2-Associated X Protein - metabolism; Caspase 3 - metabolism; caspase-3; cell cycle; Cell Cycle Checkpoints - drug effects; Cell Line, Tumor; Cervical cancer; Cyclin-Dependent Kinase Inhibitor p21 - metabolism; HeLa Cells; Humans; K562 Cells; MCF-7 Cells; ortho-Aminobenzoates - chemistry; Proto-Oncogene Proteins c-bcl-2 - metabolism; Pyrazoles - chemistry; Pyrimidines - chemistry; roscovitine; Tumor Suppressor Protein p53 - agonists; Tumor Suppressor Protein p53 - metabolism
• ISSN: 1860-7179; 1860-7187
• DOI: 10.1002/cmdc.201200205

A library of new anthranilamide–pyrazolo[1,5‐a]pyrimidine conjugates were designed, synthesized, and evaluated for their anticancer activity in cervical cancer cells such as HeLa and SiHa that possess low levels of p53. All 24 conjugates showed antiproliferative activity, while some of them exhibit significant cytotoxicity. In assays related to cell‐cycle distribution, these conjugates induced G2/M arrest in HeLa cells and G1 cell‐cycle arrest in SiHa cells. Immunocytochemistry assays revealed that these compounds cause nuclear translocation of p53, thereby indicating the activation of p53. In cervical cancer cells, the p53 protein is degraded by E6 oncoprotein. Immunoblot and RT‐PCR analyses proved the presence of mitochondria‐mediated apoptosis with involvement p53 target genes such as BAX, Bcl2, and p21 (CDKI). Moreover, these compounds increased the phosphorylated forms of p53 and provide signals for apoptosis induction. Interestingly, one of the conjugates, (2‐phenyl‐7‐(3,4,5‐trimethoxyphenyl)pyrazolo[1,5‐a]pyrimidin‐5‐yl)(4‐(2‐(thiophen‐2‐ylmethylamino)benzoyl)piperazin‐1‐yl)methanone, is the most promising candidate in this series and has the potential to be taken up for further detailed studies. Joining forces: A series of anthranilamide–pyrimidine conjugates were synthesized and evaluated for anticancer activity. Not only do these compounds regulate the cell cycle, they also induce p53 expression and p21 transcription levels. The conjugates also induce BAX protein and decrease Bcl2 protein levels, effecting caspase‐3‐mediated apoptosis. Compounds that can induce p53 are of great value and are likely to be useful in the treatment of cancer.