In BMC Cancer this week, researchers in Japan report on methylation in the KEAP1 gene promoter region, and its effects in colorectal cancer. The team examined colorectal cancer cell lines and tissue samples — eight of 10 cell lines had hypermethylated CpG islands in the KEAP1 promoter region, as did 53 percent of 40 tumor tissues tested. "HT29 cells with a hypermethylated KEAP1 promoter resulted in decreased mRNA and protein expression but unmethylated Colo320DM cells showed higher expression levelsm" the authors write. "In addition, treatment with the DNA methyltransferase inhibitor 5-Aza-dC combined with the histone deacetylase inhibitor trichostatin A (TSA) increased KEAP1 mRNA expression." This suggests that methylation of the KEAP1 promoter regulates its mRNA level, they add.
Also in BMC Cancer this week, Bacopulos et al. examine the effects of partner proteins on the activity of the BCA2 RING ligase, which is connected to hormone-responsive breast cancers. The team identified 10 unique BCA2 interacting proteins, two of which — hHR23a and 14-3-3sigma — are co-expressed with BCA2 in breast cancer cell lines and patient tumor samples. They also found that "hHR23a and BCA2 expression was significantly correlated in both nucleus and cytoplasm" and that "BCA2 expression showed a statistically significant correlation with tumor grade. High cytoplasmic hHR23a trended towards negative nodal status."
Finally in BMC Cancer, researchers in Brazil report on the anti-apoptotic gene transcription signature of salivary gland neoplasms. The team analyzed 20 fresh samples of benign salivary neoplasms and seven malignant neoplasms, and found that the BCL-2 mRNA is over-expressed, leading to "an overall anti-apoptotic profile." The researchers also found an association between the anti-apoptotic index and p53 immuno-expression. "A higher proliferative activity was found in the malignant tumours," the authors write. "In addition, tumour size was associated with cell proliferation but not with the transcription of apoptotic genes."