Résumé
Lysine acetyltransferase 5 (KAT5), a member of the MYST family, can participate in cellular processes such as transcription, DNA repair, differentiation and signal transduction by acetylating different substrates. The role of KAT5 cannot be replaced by other MYST family members, and the knockout of KAT5 can directly lead to apoptosis, indicating that KAT5 may be located in the upstream of physiological signaling pathways in cells and play an extremely important and unique role. Therefore, the changes in KAT5 expression are very likely to lead to the occurrence and development of tumors. Previous studies have found that KAT5 is downregulated in breast cancer, melanoma, and lung cancer, and is considered a tumor suppressor in these tumors. However, in recent years, studies have found that KAT5 can be either highly or lowly expressed in breast cancer, liver cancer, melanoma, prostate cancer, lung cancer and other tumors. On the premise of high KAT5 expression, KAT5 can play a tumor-promoting role. While on the premise of low KAT5 expression, KAT5 can also play as a tumor suppressor. With further decrease of KAT5 expression, its tumor suppressive effect is weakened, which may lead to the occurrence and development of tumors. In addition, KAT5 has also been found to be differentially expressed in osteosarcoma, thyroid cancer, glioblastoma, colorectal cancer and other tumors, and the differential expression of KAT5 is closely related to the proliferation, metastasis, apoptosis, drug and radiotherapy resistance of tumor cells. Therefore, KAT5 is one of the potential tumor therapeutic targets. Here, we summarize the expression of KAT5 in tumors and the tumor-suppressing or tumor-promoting signaling pathways involved in the corresponding expression in recent years, hoping to provide new inspiration and reference for tumor treatment and prognosis monitoring.
Résumé
@#【Objective】To study the expression of Tip60（KAT5）in Oral squamous cell carcinoma（OSCC），and to investigate the relationship of Tip60（KAT5）and OSCC.【Methods】Forty-nine samples of OSCC and 36 samples of nor⁃ mal tissue adjacent to OSCC were collected and analyzed retrospectively. The expression of Tip60（KAT5）was detected by immunehisto chemistry using Envision detection system. OSCC cell line Cal27 and UM1 cultured in vitro were treated with Nu9056，an inhibitor of Tip60（KAT5）for 24h，respectively. Then the effect of different concentrations and times on the growth of Cal27 and UM1 cells was evaluated with MTT assay.【Results】The expression of Tip60（KAT5）in OSCC was significantly higher than that in normal tissue adjacent to OSCC（P=0.000）. Its expression was significantly positively correlated with the degree of histological differentiation（r=0.461，P=0.001）. With the increase of concentration，the proliferation inhibition rate of Nu9056 on Cal27 and UM1 cells gradually increased，showing a concentration- dependent and time-dependent relationship（P<0.05）.【Conclusions】The expression of Tip60（KAT5）protein in oral squamous cell carcinoma tissues was related to the degree of histological differentiation ，Tip60（KAT5）can be used as oral squamous cell carcinoma progression and prognosis of biological indicators.
Résumé
Natural antisense transcripts (NAT) and alternative polyadenylation (APA) of messenger RNA (mRNA) are important contributors of transcriptome complexity, each playing a critical role in multiple biological processes. However, whether they have crosstalk and function collaboratively is unclear. We discovered that APA enriched in human sense-antisense (S-AS) gene pairs, and finally focused on RNASEH2C-KAT5 S-AS pair for further study. In cis but not in trans over-expression of the antisense KAT5 gene promoted the usage of distal polyA (pA) site in sense gene RNASEH2C, which generated longer 3' untranslated region (3'UTR) and produced less protein, accompanying with slowed cell growth. Mechanistically, elevated Pol II occupancy coupled with SRSF3 could explain the higher usage of distal pA site. Finally, NAT-mediated downregulation of sense gene's protein level in RNASEH2C-KAT5 pair was specific for human rather than mouse, which lacks the distal pA site of RNASEH2C. We provided the first evidence to support that certain gene affected phenotype may not by the protein of its own, but by affecting the expression of its overlapped gene through APA, implying an unexpected view for understanding the link between genotype and phenotype.