Filamin B extensively regulates transcription and alternative splicing, and is associated with apoptosis in HeLa cells

Abstract

Post-transcriptional mechanisms are an important approach in the treatment of cancer, and may also be hijacked by tumor cells to help adapt to the local microenvironment. Filamin B (FLNB), an actin-binding protein that provides crucial scaffolds for cell motility and signaling, has also been identified as an RNA-binding protein. Recent studies demonstrated that FLNB might play an important role, not only in skeletal development, but also in regulating tumorigenesis; however, the effects of dysregulated expression of FLNB at the molecular level are not clear. In the present study, RNA-sequencing was performed to analyze changes in overall transcriptional and alternative splicing between the knocked-down FLNB and the control in HeLa cells. Decreased FLNB levels resulted in significantly lower apoptosis compared with control cells. FLNB knockdown extensively regulated the expression of genes in cell apoptosis, tumorigenesis, metastases, transmembrane transport and cartilage development. Moreover, FLNB regulated alternative splicing of a large number of genes involved in 'cell death' and the 'apoptotic process'. Some genes and alternative splicing related to skeletal development were enriched and regulated by FLNB. Reverse transcription-quantitative-PCR identified FLNB-regulated transcription and alternative splicing of genes, such as NLR family apoptosis inhibitory protein, interleukin 23 subunit α, metastasis associated lung adenocarcinoma transcript 1, phosphofurin acidic cluster sorting protein 2, bone morphogenetic protein 7, matrix metallopeptidase 13, collagen type II α 1 chain, fibroblast growth factor receptor 2 and vitamin D receptor. The present study is the first study, to the best of the authors' knowledge, to provide transcriptome-wide analysis of differential gene expression and alternative splicing upon FLNB silencing. The present results suggested that FLNB may play an important regulatory role in cervical cancer cell apoptosis via regulation of transcription and alternative splicing, which provide insight for the current understanding of the mechanisms of FLNB-mediated gene regulation.

Chronic temperature stress effects on the liver proteome of two threespine stickleback (Gasterosteus aculeatus) populations using a novel DIA assay library

“…Two lysosomal proteins (legumain and acid phosphatase 2, lysosomal) were likewise lower in abundance in BL25. Filamin B is an actin-binding cytoskeletal protein, but also binds RNA and decreased transcript levels of filamin B have resulted in downregulation of apoptosis and genes that function in immunity and inflammation (76), which is consistent with some of the functions discussed above. Besides the common proteins involved in lipid metabolism that were significantly lower in abundance in both populations as mentioned above (sterol carrier protein 2a, phytanoyl-CoA 2-hydroxylase, fatty acid synthase), an additional lipid metabolism protein (lipase) was significantly reduced in the BL population.…”

Age and Blood Pressure Contribute to Aortic Cell and Tissue Stiffness Through Distinct Mechanisms

“…41 Dysregulated splicing of Fln B was also found to regulate tumor cell plasticity. 42 Our results from this study revealed that Fln B was significantly decreased with increasing age, accompanied by an increase in Fln A and active integrin β1 in older WKY VSMCs, which were not reversed by CCG. Together with the previous results, it is reasonable to postulate that disruption of Fln B to A balance may target upstream mediators of Rho/SRF signaling, regulating VSMC plasticity in an SRF-aSMA–independent manner, which may explain the ineffectiveness of CCG in counteracting aging-related aortic stiffness.…”

Transcriptomics analysis of ethanol treatment of male Aedes aegypti reveals a small set of putative radioprotective genes

“…The filamin b gene ( flnb ) encodes an actin-binding protein that can cross-link actin filaments and link actin filaments to membrane-bound proteins ( Nakamura et al, 2011 ). In addition to its actin-binding functions, FlnB has also been demonstrated to play a role in alternative splicing of apoptosis-related transcripts in HeLa cell death ( Ma et al, 2020 ), and pro-apoptotic effects as a part of the type I interferon signaling pathway as assayed in mammalian cells ( Jeon et al, 2008 ; Whitmarsh, 2009 ). Tubulin polyglutamylase TTLL5 (TTLL5) is a microtubule associated protein that glutamylates alpha tubulin subunits.…”