We demonstrate that SV infection of baby hamster kidney (BHK-2), mouse neuroblastoma (N18), and rat prostatic adenocarcinoma (AT-3) cells results in programmed cell death, whereas SV infection of bcl-2-transfected AT-3 cells results in long-term persistent productive infection.
In 10 matched-pair cell lines [established at diagnosis (DX) and progressive disease (PD) from the same patients], BCL-2 expression in the DX and PD lines was comparable, suggesting that BCL-2 expression at diagnosis may provide a biomarker for neuroblastomas likely to respond to 4-HPR + ABT-199.
Using data from our large drug screen we predicted, and subsequently demonstrated, that MYCN-amplified neuroblastomas are sensitive to the BCL-2 inhibitor ABT-199.
Collectively, these results suggest that IGF-IR or Bcl-2 overexpression in neuroblastoma cells promotes cell survival by preventing mitochondrial membrane depolarization and caspase-3 activation, ultimately leading to increased tumor growth.
Identical results were obtained by treatment of the neuroblastoma cell lines with the small molecule BCL2 inhibitor ABT263, which is currently being clinically evaluated.
This accumulated evidence suggests that massive apoptosis of tumor cells occurs in some neuroblastomas and may be related to tumor regression, whereas inhibition of apoptosis by bcl-2 oncoprotein expression might be associated with the tumorigenesis of neuroblastomas, as reported in our previous study.
There was a significant reduction in p53, p21(WAF1) and Ki67 LI after chemotherapy (p < 0.01), an increase in BAX (p <0.05), but no change in Bcl2. p53 localization and function were examined in two p53 wild-type undifferentiated and 9-cis retinoic acid differentiated neuroblastoma cell lines.
LSD1 protein expression levels were assessed semi-quantitatively in specimens of NB and ganglioneuroblastoma (GNB), along with the apoptosis markers, Bcl-2 and Bax.
Ectopic expression of LGP2 in NB cells significantly enhanced poly (I:C)-induced NB cell death associated with downregulation of MDA5, RIG-I, MAVS and Bcl-2, as well as upregulation of Noxa and tBid.
For example, miR-15 and miR-16 induce apoptosis by targeting Bcl2. miRNAs from the miR-17-92 cluster modulate tumor formation and function as oncogenes by influencing the translation of E2F1 mRNA. miR-21 modulates gemcitabine-induced apoptosis by phosphatase and tensin homolog deleted on chromosome 10-dependent activation of PI 3-kinase signaling. miR-34a acts as a suppressor of neuroblastoma tumorigenesis by targeting the mRNA encoding E2F3 and reducing E2F3 protein levels.
MMP-2 expression and secretion are increased in SHEP neuroblastoma cells expressing Bcl-2 alone (SHEP/Bcl-2 cells) or both N-Myc and Bcl-2 (SHEP/N-Myc/Bcl-2 cells).
Overall, our results demonstrate the therapeutic potential of CXCR4 inhibition in neuroblastoma treatment and provide a rationale to test combination therapies employing CXCR4 and BCL-2 inhibitors to increase the efficacy of these agents.<b>Significance:</b> These results provide a mechanistic rationale for combination therapy of CXCR4 and BCL-2 inhibitors to treat a common and commonly aggressive pediatric cancer.<i></i>.
In <i>MYCN</i>-amplified neuroblastoma, PUMA induction by GSK-J4 sensitized tumors to the B cell lymphoma 2 (BCL-2) inhibitor venetoclax, demonstrating that epigenetic-targeted therapies and BCL-2 homology domain 3 mimetics can be rationally combined to treat this high-risk subset of neuroblastoma.
Our data indicate that NB differentiation induces drug resistance after a loss of the apoptotic response to antineoplastic drugs and suggest that bcl-2 overexpression is an important mechanism of resistance in differentiated tumor cells.
In addition, experiments based on siRNA transfections were performed in the human SH-SY5Y neuroblastoma cell line to verify that the stability of Bcl-2 is causal to neuronal survival.
Role of c-abl oncogene in chronic myeloid leukemia (CML), bcl-2, in lymphomas, N-myc in neuroblastomas and retinoblastoma (Rb) gene in retinoblastomas is well understood and used in designing proper therapeutic approaches.
Furthermore, the effects of Aβ and TD/GH on LDH release, apoptosis and its relevant gene expression, involving bcl-2 and bax/caspase-3, were observed in a human neuroblastoma cell line (SH-SY5Y).