Novel anthranilamide-pyrazolo[1,5-a]pyrimidine conjugates modulate the expression of p53-MYCN associated micro RNAs in neuroblastoma cells and cause cell cycle arrest and apoptosis.

It has previously been shown that anthranilamide-pyrazolo[1,5-a]pyrimidine conjugates activate p53 and cause apoptosis in cervical cancer cells such as HeLa and SiHa. Here we establish the role of these conjugates in activating p53 pathway by phosphorylation at Ser15, 20 and 46 residues and downregulate key oncogenic proteins such as MYCN and Mdm2 in IMR-32 neuroblastoma cells. Compounds decreased the proliferation rate of neuroblastoma cells such as IMR-32, Neuro-2a, SK-N-SH. Compound treatment resulted in G2/M cell cycle arrest. The expression of p53 dependent genes such as p21, Bax, caspases was increased with concomitant decrease of the survival proteins as well as anti-apoptotic proteins such as Akt1, E2F1 and Bcl2. In addition the expression of important microRNAs such as miR-34a, c, miR-200b, miR-107, miR-542-5p and miR-605 were significantly increased that eventually lead to the activation of apoptotic pathway. Our data revealed that conjugates of this nature cause cell cycle arrest and apoptosis in IMR-32 cells [MYCN (+) with intact wild-type p53] by activating p53 signalling and provides a lead for the development of anti-cancer therapeutics.

Ramaiah MJ ，Pushpavalli SN ，Lavanya A ，Bhadra K ，Haritha V ，Patel N ，Tamboli JR ，Kamal A ，Bhadra U ，Pal-Bhadra M ... -  《-》

Anthranilamide-pyrazolo[1,5-a]pyrimidine conjugates as p53 activators in cervical cancer cells.

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 G(2) /M arrest in HeLa cells and G(1) 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.

Kamal A ，Tamboli JR ，Ramaiah MJ ，Adil SF ，Koteswara Rao G ，Viswanath A ，Mallareddy A ，Pushpavalli SN ，Pal-Bhadra M ... -  《-》

Inhibition of cyclin-dependent kinase 1-induced cell death in neuroblastoma cells through the microRNA-34a-MYCN-survivin pathway.

Neuroblastoma is the most common pediatric solid extracranial malignancy. Increased expression of MYCN, a member of Myc family, is associated with a poor prognosis in patients with neuroblastoma. Cyclin-dependent kinase 1 (CDK1) is known to be critical to the survival of Myc-overexpressing neoplasms. In this study, we investigated the effects of CDK1 inhibition on the viability of neuroblastoma cells and the underlying molecular mechanisms. We assessed the effects of CDK1 inhibitors on the viability of neuroblastoma cells and explored MYCN-associated mechanisms by using real-time reverse-transcription polymerase chain reaction, chromatin immunoprecipitation, and micro-RNA quantification. CDK1 inhibitors induced cytotoxicity and apoptosis and decreased expression of MYCN and survivin in neuroblastoma cells. Knockdown of MYCN mRNA expression caused significant cell death and transcomplementation of MYCN increased cell viability in neuroblastoma cells treated with CDK1 inhibitors. Furthermore, MYCN mRNA was inhibited by CDK1 inhibitor at the posttranscriptional level. The expression of survivin was also responsive to the change of MYCN levels, and according to the chromatin immunoprecipitation assay, MYCN bound the promoter region of the survivin gene. CDK1 inhibition caused elevation of microRNA-34a (miR-34a), and anti-miR-34a not only restored the expression of MYCN but also increased cell survival of neuroblastoma cells treated with CDK1 inhibitor. CDK1 inhibition-induced cell death was dependent, although not completely, on the decreased level of MYCN- and miR-34a-mediated, CDK1 inhibition-induced down-regulation of MYCN, which thereby decreased the transcriptional activation of MYCN on the survivin promoter. We propose that CDK1 inhibition-induced cell death of neuroblastoma cells occurs through the miR-34a-MYCN-survivin pathway.

Chen Y ，Tsai YH ，Tseng SH 《-》

MYCN-directed centrosome amplification requires MDM2-mediated suppression of p53 activity in neuroblastoma cells.

Slack AD ，Chen Z ，Ludwig AD ，Hicks J ，Shohet JM ... -  《CANCER RESEARCH》

Curcumin and resveratrol induce apoptosis and nuclear translocation and activation of p53 in human neuroblastoma.

Liontas A ，Yeger H 《ANTICANCER RESEARCH》