Search

Supplementary Figure 2 from A Sensitized RNA Interference Screen Identifies a Novel Role for the PI3K p110γ Isoform in Medulloblastoma Cell Proliferation and Chemoresistance

Supplementary Figure 1 from A Sensitized RNA Interference Screen Identifies a Novel Role for the PI3K p110γ Isoform in Medulloblastoma Cell Proliferation and Chemoresistance

Supplementary Figure 3 from A Sensitized RNA Interference Screen Identifies a Novel Role for the PI3K p110γ Isoform in Medulloblastoma Cell Proliferation and Chemoresistance

Supplementary Table 1 from A Sensitized RNA Interference Screen Identifies a Novel Role for the PI3K p110γ Isoform in Medulloblastoma Cell Proliferation and Chemoresistance

Supplementary Figure 4 from A Sensitized RNA Interference Screen Identifies a Novel Role for the PI3K p110γ Isoform in Medulloblastoma Cell Proliferation and Chemoresistance

The quassinoid analogue NBT-272 has been reported to inhibit MYC, thus warranting a further effort 7to better understand its preclinical properties in models of embryonal tumors (ET), a family of childhood malignancies sharing relevant biological and genetic features such as deregulated expression of MYC oncogenes. In our study, NBT-272 displayed a strong antiproliferative activity in vitro that resulted from the combination of diverse biological effects, ranging from G1/S arrest of the cell cycle to apoptosis and autophagy. The compound prevented the full activation of both eukaryotic translation initiation factor 4E (eIF4E) and its binding protein 4EBP-1, regulating cap-dependent protein translation. Interestingly, all responses induced by NBT-272 in ET could be attributed to interference with 2 main proproliferative signaling pathways, that is, the AKT and the MEK/extracellular signal-regulated kinase pathways. These findings also suggested that the depleting effect of NBT-272 on MYC protein expression occurred via indirect mechanisms, rather than selective inhibition. Finally, the ability of NBT-272 to arrest tumor growth in a xenograft model of neuroblastoma plays a role in the strong antitumor activity of this compound, both in vitro and in vivo, with its potential to target cell-survival pathways that are relevant for the development and progression of ET. Mol Cancer Ther; 9(12); 3145–57. ©2010 AACR.

Supplementary Figures 1-4 from Disabling c-Myc in Childhood Medulloblastoma and Atypical Teratoid/Rhabdoid Tumor Cells by the Potent G-Quadruplex Interactive Agent S2T1-6OTD

We investigated here the effects of S2T1-6OTD, a novel telomestatin derivative that is synthesized to target G-quadruplex–forming DNA sequences, on a representative panel of human medulloblastoma (MB) and atypical teratoid/rhabdoid (AT/RT) childhood brain cancer cell lines. S2T1-6OTD proved to be a potent c-Myc inhibitor through its high-affinity physical interaction with the G-quadruplex structure in the c-Myc promoter. Treatment with S2T1-6OTD reduced the mRNA and protein expressions of c-Myc and hTERT, which is transcriptionally regulated by c-Myc, and decreased the activities of both genes. In remarkable contrast to control cells, short-term (72-hour) treatment with S2T1-6OTD resulted in a dose- and time-dependent antiproliferative effect in all MB and AT/RT brain tumor cell lines tested (IC50, 0.25–0.39 μmol/L). Under conditions where inhibition of both proliferation and c-Myc activity was observed, S2T1-6OTD treatment decreased the protein expression of the cell cycle activator cyclin-dependent kinase 2 and induced cell cycle arrest. Long-term treatment (5 weeks) with nontoxic concentrations of S2T1-6OTD resulted in a time-dependent (mainly c-Myc–dependent) telomere shortening. This was accompanied by cell growth arrest starting on day 28 followed by cell senescence and induction of apoptosis on day 35 in all of the five cell lines investigated. On in vivo animal testing, S2T1-6OTD may well represent a novel therapeutic strategy for childhood brain tumors. Mol Cancer Ther; 9(1); 167–79

Purpose: The phosphoinositide 3-kinase (PI3K)/Akt pathway is frequently activated in human cancer and plays a crucial role in neuroblastoma biology. We were interested in gaining further insight into the potential of targeting PI3K/Akt signaling as a novel antiproliferative approach in neuroblastoma.Experimental Design: The expression pattern and functions of class IA PI3K isoforms were investigated in tumor samples and cell lines. Effects on cell survival and downstream signaling were analyzed following down-regulation of p110α or p110δ in SH-SY5Y and LA-N-1 cells by means of RNA interference.Results: Overexpression of the catalytic p110δ and regulatory p85α isoforms was detected in a panel of primary neuroblastoma samples and cell lines, compared with normal adrenal gland tissue. Although down-regulation of either p110α or p110δ led to impaired cell growth, reduced expression of p110δ also had a selective effect on the survival of SH-SY5Y cells. Decreased levels of p110δ were found to induce apoptosis and lead to lower expression levels of antiapoptotic Bcl-2 family proteins. SH-SY5Y cells with decreased p110δ levels also displayed reduced activation of ribosomal protein S6 kinase in response to stimulation with epidermal growth factor and insulin-like growth factor-I.Conclusions: Together, our data reveal a novel function of p110δ in neuroblastoma growth and survival.

Supplementary Data from The Quassinoid Derivative NBT-272 Targets Both the AKT and ERK Signaling Pathways in Embryonal Tumors

Supplementary Methods, Figure Legends 1-4 from Disabling c-Myc in Childhood Medulloblastoma and Atypical Teratoid/Rhabdoid Tumor Cells by the Potent G-Quadruplex Interactive Agent S2T1-6OTD

Supplementary Figures S1-S2 from Targeting the Phosphoinositide 3-Kinase Isoform p110δ Impairs Growth and Survival in Neuroblastoma Cells

Purpose: The phosphoinositide 3-kinase (PI3K)/Akt pathway is frequently activated in human cancer and plays a crucial role in medulloblastoma biology. We were interested in gaining further insight into the potential of targeting PI3K/Akt signaling as a novel antiproliferative approach in medulloblastoma. Experimental Design: The expression pattern and functions of class IA PI3K isoforms were investigated in medulloblastoma tumour samples and cell lines. Effects on cell survival and downstream signaling were analyzed following down-regulation of p110α, p110β, or p110δ by means of RNA interference or inhibition with isoform-specific PI3K inhibitors. Results: Overexpression of the catalytic p110α isoform was detected in a panel of primary medulloblastoma samples and cell lines compared with normal brain tissue. Down-regulation of p110α expression by RNA interference impaired the growth of medulloblastoma cells, induced apoptosis, and led to decreased migratory capacity of the cells. This effect was selective, because RNA interference targeting of p110β or p110δ did not result in a comparable impairment of DAOY cell survival. Isoform-specific p110αinhibitors also impaired medulloblastoma cell proliferation and sensitized the cells to chemotherapy. Medulloblastoma cells treated with p110α inhibitors further displayed reduced activation of Akt and the ribosomal protein S6 kinase in response to stimulation with hepatocyte growth factor and insulin-like growth factor-I. Conclusions: Together, our data reveal a novel function of p110α in medulloblastoma growth and survival.

Purpose: The phosphoinositide 3-kinase (PI3K)/Akt pathway is frequently activated in human cancer and plays a crucial role in neuroblastoma biology. We were interested in gaining further insight into the potential of targeting PI3K/Akt signaling as a novel antiproliferative approach in neuroblastoma.Experimental Design: The expression pattern and functions of class IA PI3K isoforms were investigated in tumor samples and cell lines. Effects on cell survival and downstream signaling were analyzed following down-regulation of p110α or p110δ in SH-SY5Y and LA-N-1 cells by means of RNA interference.Results: Overexpression of the catalytic p110δ and regulatory p85α isoforms was detected in a panel of primary neuroblastoma samples and cell lines, compared with normal adrenal gland tissue. Although down-regulation of either p110α or p110δ led to impaired cell growth, reduced expression of p110δ also had a selective effect on the survival of SH-SY5Y cells. Decreased levels of p110δ were found to induce apoptosis and lead to lower expression levels of antiapoptotic Bcl-2 family proteins. SH-SY5Y cells with decreased p110δ levels also displayed reduced activation of ribosomal protein S6 kinase in response to stimulation with epidermal growth factor and insulin-like growth factor-I.Conclusions: Together, our data reveal a novel function of p110δ in neuroblastoma growth and survival.