In this study, we demonstrated that necrosis-inducing peptide P16 kills human glioblastoma cancer cells and primary human hepatoma or renal cancer cells isolated from patients who had not responded to standard treatments.
Because mutations of FANCA and BRAF and copy number variations of CDKN2A/B are more frequent in PXA than in glioblastoma, they might be used to distinguish the 2 tumors.
Nevertheless, specific mutations of p14ARF have been described in different types of human cancers such as colorectal and gastric carcinomas, melanoma and glioblastoma.
On real cancer data, pathTiMEx recapitulates previous knowledge on tumorigenesis, such as the temporal order among pathways which include APC, KRAS, and TP53 in colorectal cancer, while also proposing new biological hypotheses, such as the existence of a single early causal event consisting of the amplification of CDK4 and the deletion of CDKN2A in glioblastoma. pathTiMEx is available as an R package.
Tumor types were characterized by specific broad and focal chromosomal events including focal loss of the INK4A/B locus in glioblastoma and loss of the RB1 gene and amplification of the PDGFRA gene in oligodendrogliomas.
The tumoricidal and TMZ-sensitizing effects of BI2536 were uniformly observed across Ink4a/Arf(-/-) EGFRvIII glioblastoma clones that acquired independent resistance mechanisms to EGFR inhibitors, suggesting these resistant clones retain oncogenic stress that required PLK1 compensation.
Intriguingly, our data also suggest that nearly half of GB cell lines have a combination of TP53 mutation and CDKN2A homozygous deletion, which are considered as mutually exclusive in glioblastoma.
Finally, the G-CIMP+ Ink4a-Arf-/- EGFRvIII glioblastoma line was more resistant to the EGFR inhibitor, Gefitinib, relative to its isogenic G-CIMP- counterpart.
Comparative genomic hybridization analysis demonstrated that no chromosomal abnormality was found in the GCA; however, a gain of chromosomes 7 and 19 and a loss of chromosomes 10 and 9p21 (CDKN2A) were found in the glioblastoma. p53 was strongly expressed in both the GCA and glioblastoma.
Immunohistochemical studies showed substantial overlap in Ki-67 labeling indices, an imperfect correlation between p53 labeling and TP53 mutation status, and complete p16 loss in only two pGBMs but in no PAs.
We treated human glioblastoma cells with BP and found a dose-dependent decrease in human telomerase reverse transcriptase (hTERT) mRNA expression and a concomitant increase in p16 and p21 expression.
Because the INK4a-ARF locus is often deleted in high-grade gliomas (anaplastic oligodendroglioma and glioblastoma), we investigated the effect of the Ink4a-Arf-null background on IGFBP2-mediated progression of PDGFB-initiated oligodendroglioma.
Additionally, the combination of p16 and p21(CIP1) (p21-S154A) peptides dramatically suppressed the growth of glioblastoma line Gli36DeltaEGFR, which carries a missense mutation in p53, by >97% after 120 h. Significantly, our murine brain tumor model for dual-peptide delivery showed a substantial average survival enhancement (P < 0.0001) for peptide-treated mice.
The U251 glioblastoma and a glioblastoma xenograft cell line transduced with a recombinant replication-defective adenovirus vector containing the cDNA of wild-type p16 and antisense RNA of uPAR significantly inhibited human mammary epithelial cell capillary formation and vascular endothelial growth factor (VEGF) expression.
On analysis of their respective recurrent tumors, five of six patients whose primary low-grade tumors carried p14(ARF) methylation exhibited homozygous co-deletions of the p14(ARF), p15(INK4b) and p16(INK4a) genes, which were restricted to glioblastoma as the most malignant end point.
The concomitant 1p partial loss and chromosome 19 alterations, with the +7 and -10-specific GBM markers associated with homozygous deletion of 9p21.3 including CDKN2A (p16), are distinct features of the glioblastoma MI-4 cell line, illustrating its origin from an olidodendroglial tumor.
In this study, we evaluated the genetic status of 32 glioblastomas by comparative genomic hybridization; the sensitivity of comparative genomic hybridization versus differential polymerase chain reaction to detect deletions at the phosphatase and tensin homologue deleted in chromosome 10, deleted in malignant brain tumors-1, and cyclin-dependent kinase inhibitor 2A loci and amplifications at the cyclin-dependent kinase 4 locus; the frequency of genetic lesions (gain or loss) at 16 different selected loci (including oncogenes, tumor-suppressor genes, and proliferation markers) mapping on 13 different chromosomes; and the possible existence of a statistical association between any pair of molecular markers studied, to subdivide the glioblastoma entity molecularly.