Main author: Hong Nhung VU
Institution or Company: Department of Biochemistry and Molecular Biology, BioMedical Center, Faculty of Medicine, University of Iceland
Co-Authors, Institution or Company:
Ramile Dilshat, Department of Biochemistry and Molecular Biology, BioMedical Center, Faculty of Medicine, University of Iceland. Eiríkur Steingrímsson, Department of Biochemistry and Molecular Biology, BioMedical Center, Faculty of Medicine, University of Iceland.
Introduction: Microphthalmia-associated transcription factor (MITF) is known as an essential regulator of melanocyte specification, melanoma cell proliferation, invasion, and drug resistance. The major changes in gene expression of MITF knockout melanoma cells has led to the proposal that MITF might regulate the expression of epigenetic modifiers which subsequently reshape the melanoma chromatin state. Consistent with this, the expression of the histone methyltransferase PRDM7 was observed to be significantly reduced upon MITF knockout and increased upon MITF overexpression. Interestingly, PRDM7 is a primate specific gene that is primarily expressed in melanoma among all cancers analyzed in the Cancer Genome Atlas. However, the biological roles of PRDM7 remain elusive.
Methods: PRDM7 CRISPR knockout melanoma cells were generated to study the functional roles of PRDM7 in melanoma proliferation, invasion and colony formation ability. Additionally, transcriptome of PRDM7-KO cells was determined and compared with their corresponding control.
Results: While the depletion of PRDM7 in both SKmel28 and 501Mel cell lines resulted in a significant reduction of colony formation ability, only 501Mel PRDM7-KO cells had slower proliferation and wound-scratch migration rate compared to its corresponding control. Both the 501Mel and SKmel28 cells had altered morphologies and cytoskeletal structures upon PRDM7 loss as observed in phase contrast images and vimentin immunostaining. Consistent with that, RNA-sequencing of PRDM7-KO cells showed increased expression of genes involved in extracellular matrix and structure organization in the PRDM7-KO cells. Interestingly, the same class of genes is increased in expression when MITF is knocked out.
Conclusions: The results suggested that PRDM7 plays roles in melanoma cell proliferation and migration. Furthermore, MITF might regulate the expression of extracellular matrix genes through PRDM7.
