RESUMO
Histone H3 lysine 79 (H3K79) methyltransferase DOT1L plays an important role in the activation and maintenance of gene transcription; it is also essential for maintenance of embryonic development, as well as the normal function of hematopoietic system, heart and kidney. However, the over expression of DOT1L is associated with the occurring and progress of numerous malignant tumors, so more and more attention has been paid to DOT1L. Therefore, it is of great significance to study and develop inhibitors of DOT1L. The inhibitors could serve as a tool in the investigation of the biological function, and have the potential to be developed into novel anti-cancer agents in the anticancer therapy. This paper mainly describes the structure and function of DOT1L, the relationship between DOT1L and tumors as well as the latest research progress of DOT1L inhibitors; with expect to provide some useful references for the subsequent research.
RESUMO
Objective To analyze the role of hDOT1L signaling pathway on the proliferation of human acute monocytic leukemia cell line THP-1 cell inhibited by demcitabine, and to explore the other effects except DNA demethylation and the mechanism of hDOT1L signaling pathways involved in leukemia. Methods Methyl thiazolyl tetrazolium (MTT) method was used to detect the influence of decitabine on THP-1 cell proliferation, and trypan blue anti-staining was applied to detect the effect of decitabine on THP-1 cell survival rate, reverse transcriptase polymerase chain reaction (RT-PCR) was used to detect the expression levels of hDOT1L, HOXA9, HOXA10, MLL-AF10 (MLLT10) mRNA, then the methylation level of H3K79 was detected by Western blotting assay. Results Compared with the control group, decitabine inhibited the proliferation of THP-1 cell in a time and dose-dependent manner. The inhibitory effect of 72 h was the highest, and the highest inhibition rate was 56.18%. In addition to 0.5 μmol/L in decitabine treatment group, the other groups were statistically significant (all P<0.05). There were high expressions of hDOT1L, HOXA9, HOXA10, MLLT10 mRNA and H3K79 hypermethylation in the THP-1 cell, meanwhile decitabine reduced the levels of hDOT1L mRNA after 48 h as well as HOXA9, HOXA10, MLLT10 mRNA, and there was a significant difference compared with the control group (all P < 0.01). Decitabine reduced obviously the methylation of H3K79 in cell after 48 h, especially the expression levels of bis and three methyl protein, and these differences were significant compared with the control group (all P< 0.01). Conclusion Decitabine plays its inhibitory effect on the proliferation of THP-1 cells probably through reducing the expression level of hDOT1L and H3K79 methylation level and decreasing the expression levels of key molecules, HOXA9, MLL-AF10, HOXA10, MLLT10 in the hDOT1L signal pathway.
RESUMO
Objective · To investigate the histone methyltransferase capability of DOT1L-long form and its role in breast cancer metastasis.Methods · The existence of DOT1L-long form was confirmed by PCR, and the mRNA level of DOT1L was tested by real-time PCR. In HEK293T cells in which DOT1L canonical and DOT1L-long were overexpressed respectively, Western blotting was used to test the expression level of DOT1L and the histone methyltransferase capability. In the MCF10A cell line with inducible expression of DOT1L-long, real-time PCR was used to detect the mRNA level of epithelial-mesenchymal transition (EMT) marker, and transwell assay was used to detect the migration of breast cancer cells in which the expression level of DOT1L is low or high. Results · PCR demonstrated the existence of DOT1L-long form, and real-time PCR showed it widely exists in HCT116, T98G, MCF10A cells, etc. Western blotting showed the expression of DOT1L-long form and its H3K79 methyltransferase activity. In MCF10A cells in which overexpressed canonical DOT1L and DOT1L-long, mRNA levels of N-cadherin and fibronectine increased. Transwell showed canonical DOT1L and DOT1L-long both substantially increased the migration of breast cancer cells. Conclusion · The existence of DOT1L-long was confirmed and investigated, which is 202 amino acids longer than the canonical DOT1L, and is coded by a new exon, located between exon 27 and 28. Further, the DOT1L-long has H3K79 methyltransferase activity, and is able to promote breast cancer metastasis.
RESUMO
Objective · To investigate the histone methyltransferase capability of DOT1L-long form and its role in breast cancer metastasis.Methods · The existence of DOT1L-long form was confirmed by PCR, and the mRNA level of DOT1L was tested by real-time PCR. In HEK293T cells in which DOT1L canonical and DOT1L-long were overexpressed respectively, Western blotting was used to test the expression level of DOT1L and the histone methyltransferase capability. In the MCF10A cell line with inducible expression of DOT1L-long, real-time PCR was used to detect the mRNA level of epithelial-mesenchymal transition (EMT) marker, and transwell assay was used to detect the migration of breast cancer cells in which the expression level of DOT1L is low or high. Results · PCR demonstrated the existence of DOT1L-long form, and real-time PCR showed it widely exists in HCT116, T98G, MCF10A cells, etc. Western blotting showed the expression of DOT1L-long form and its H3K79 methyltransferase activity. In MCF10A cells in which overexpressed canonical DOT1L and DOT1L-long, mRNA levels of N-cadherin and fibronectine increased. Transwell showed canonical DOT1L and DOT1L-long both substantially increased the migration of breast cancer cells. Conclusion · The existence of DOT1L-long was confirmed and investigated, which is 202 amino acids longer than the canonical DOT1L, and is coded by a new exon, located between exon 27 and 28. Further, the DOT1L-long has H3K79 methyltransferase activity, and is able to promote breast cancer metastasis.