Search results for: Khalsa Al Lamki

Authors: Mohammed N. Al Kindi, Mazin Al Khabouri, Khalsa Al Lamki, Tommasso Pappuci, Giovani Romeo, Nadia Al Wardy

Abstract:

Hereditary hearing loss is a heterogeneous group of complex disorders with an overall incidence of one in every five hundred newborns presented as syndromic and non-syndromic forms. Cadherin-related 23 (CDH23) is one of the listed deafness causative genes. CDH23 is found to be expressed in the stereocilia of hair cells and the retina photoreceptor cells. Defective CDH23 has been associated mostly with prelingual severe-to-profound sensorineural hearing loss (SNHL) in either syndromic (USH1D) or non-syndromic SNHL (DFNB12). An Omani family diagnosed clinically with severe-profound sensorineural hearing loss was genetically analysed by whole exome sequencing technique. A novel homozygous missense variant, c.A7451C (p.D2484A), in exon 53 of CDH23 was detected. One hundred and thirty control samples were analysed where all were negative for the detected variant. The variant was analysed in silico for pathogenicity verification using several mutation prediction software. The variant proved to be a pathogenic mutation and is reported for the first time in Oman and worldwide. It is concluded that in silico mutation prediction analysis might be used as a useful molecular diagnostics tool benefiting both genetic counseling and mutation verification. The aspartic acid 2484 alanine missense substitution might be the main disease-causing mutation that damages CDH23 function and could be used as a genetic hearing loss marker for this particular Omani family.

Keywords: Cdh23, d2484a, in silico, Oman

Procedia PDF Downloads 192

Authors: Rafia S. Al-lamki, Jun Wang, Simon Pacey, Jordan Pober, John R. Bradley

Abstract:

Tumor necrosis factor alpha (TNF), signaling through TNFR2, may act an autocrine growth factor for renal tubular epithelial cells. Clear cell renal carcinomas (ccRCC) contain cancer stem cells (CSCs) that give rise to progeny which form the bulk of the tumor. CSCs are rarely in cell cycle and, as non-proliferating cells, resist most chemotherapeutic agents. Thus, recurrence after chemotherapy may result from the survival of CSCs. Therapeutic targeting of both CSCs and the more differentiated bulk tumor populations may provide a more effective strategy for treatment of RCC. In this study, we hypothesized that TNFR2 signaling will induce CSCs in ccRCC to enter cell cycle so that treatment with ligands that engage TNFR2 will render CSCs susceptible to chemotherapy. To test this hypothesis, we have utilized wild-type TNF (wtTNF) or specific muteins selective for TNFR1 (R1TNF) or TNFR2 (R2TNF) to treat either short-term organ cultures of ccRCC and adjacent normal kidney (NK) tissue or cultures of CD133+ cells isolated from ccRCC and adjacent NK, hereafter referred to as stem cell-like cells (SCLCs). The effect of cyclophosphamide (CP), currently an effective anticancer agent, was tested on CD133+SCLCs from ccRCC and NK before and after R2TNF treatment. Responses to TNF were assessed by flow cytometry (FACS), immunofluorescence, and quantitative real-time PCR, TUNEL, and cell viability assays. Cytotoxic effect of CP was analyzed by Annexin V and propidium iodide staining with FACS. In addition, we assessed the effect of TNF on isolated SCLCs differentiation using a three-dimensional (3D) culture system. Clinical samples of ccRCC contain a greater number SCLCs compared to NK and the number of SCSC increases with higher tumor grade. Isolated SCLCs show expression of stemness markers (oct4, Nanog, Sox2, Lin28) but not differentiation markers (cytokeratin, CD31, CD45, and EpCAM). In ccRCC organ cultures, wtTNF and R2TNF increase CD133 and TNFR2 expression and promote cell cycle entry whereas wtTNF and R1TNF increase TNFR1 expression and promote cell death of SCLCs. Similar findings are observed in SCLCs isolated from NK but the effect was greater in SCLCs isolated from ccRCC. Application of CP distinctly triggered apoptotic and necrotic cell death in SLCSs pre-treatment with R2TNF as compared to CP treatment alone, with SCLCs from ccRCC more sensitive to CP compared to SLCS from NK. Furthermore, TNF promotes differentiation of SCLCs to an epithelial phenotype in 3D cultures, confirmed by cytokeratin expression and loss of stemness markers Nanog and Sox2. The differentiated cells show positive expression of TNF and TNFR2. These findings provide evidence that selective engagement of TNFR2 drive CSCs to cell proliferation/differentiation, and targeting of cycling cells with TNFR2 agonist in combination with anti-cancer agents may be a potential therapy for RCC.

Keywords: cancer stem cells, ccRCC, cell cycle, cell death, TNF, TNFR1, TNFR2, CD133

Procedia PDF Downloads 245