Omar H. M. Shair

Omar H. M. Shair

*This is an algorithmically generated author record based on publicly available information.

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Omar H. M. Shair has a total of 14 co-authors. Here are the top co-authors by number of shared publications:


Latest Publications

  • Open Access

    RESPONSE OF SOIL MICROORGANISMS TO MALATHION IN SAUDI ARABIA

    by Omar M. H. Shair, Rashead M. Alssum

    Microorganisms play an extensive role in the decomposition of many organic matters and are in symbiotic relationship with plants and animals. In this study, concentration containing 57 mg/ml malathion was diluted and used to spray soil sample collected from Riyadh area, Saudi Arabia Total chromosomal soil microorganisms were isolated from sprayed and non sprayed samples. Absence and presences of PCR band profiles were assumed to represent the absence or presence of bacteria. A maximum 7mg/ml and minimum 0.2mg/4.16 ul of malathion concentration was used in a nutrient agar medium for bacterial growth. The fingerprinting profiles of treated soil samples demonstrated the missing of some fingerprint bands which were present in the profiles of non treated soil samples. It was concluded that malathion had a misbalancing effect on the soil flora bacteria. However, smearing with maximum malathion concentration in nutrient agar supporting bacterial growth was observed. While a minimum concentration in the same nutrient agar was not supporting.

  • Open Access

    Celastrol Alleviates Gamma Irradiation-Induced Damage by Modulating Diverse Inflammatory Mediators

    by Hong Wang, Kwang Seok Ahn, Sulaiman Ali Alharbi, Omar H. M. Shair, Frank Arfuso, Gautam Sethi, Arunachalam Chinnathambi, Feng Ru Tang

    The present study aimed to explore the possible radioprotective effects of celastrol and relevant molecular mechanisms in an in vitro cell and in vivo mouse models exposed to gamma radiation. Human keratinocytes (HaCaT) and foreskin fibroblast (BJ) cells were exposed to gamma radiation of 20 Gy, followed by treatment with celastrol for 24 h. Cell viability, reactive oxygen species (ROS), nitric oxide (NO) and glutathione (GSH) production, lipid peroxidation, DNA damage, inflammatory cytokine levels, and NF-κB pathway activation were examined. The survival rate, levels of interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-α) in blood, and p65 and phospho-p65 expression were also evaluated in mice after exposure to gamma radiation and celastrol treatment. The gamma irradiation of HaCaT cells induced decreased cell viability, but treatment with celastrol significantly blocked this cytotoxicity. Gamma irradiation also increased free radical production (e.g., ROS and NO), decreased the level of GSH, and enhanced oxidative DNA damage and lipid peroxidation in cells, which were effectively reversed by celastrol treatment. Moreover, inflammatory responses induced by gamma irradiation, as demonstrated by increased levels of IL-6, TNF-α, and IL-1β, were also blocked by celastrol. The increased activity of NF-κB DNA binding following gamma radiation was significantly attenuated after celastrol treatment. In the irradiated mice, treatment with celastrol significantly improved overall survival rate, reduced the excessive inflammatory responses, and decreased NF-κB activity. As a NF-κB pathway blocker and antioxidant, celastrol may represent a promising pharmacological agent with protective effects against gamma irradiation-induced injury.


  • Open Access

    Fangchinoline, a Bisbenzylisoquinoline Alkaloid can Modulate Cytokine-Impelled Apoptosis via the Dual Regulation of NF-κB and AP-1 Pathways

    by Young Yun Jung, Muthu K. Shanmugam, Arunachalam Chinnathambi, Sulaiman Ali Alharbi, Omar H.M. Shair, Jae-Young Um, Gautam Sethi, Kwang Seok Ahn

    Fangchinoline (FCN) derived from Stephaniae tetrandrine S. Moore can be employed to treat fever, inflammation, rheumatism arthralgia, edema, dysuria, athlete’s foot, and swollen wet sores. FCN can exhibit a plethora of anti-neoplastic effects although its precise mode of action still remains to be deciphered. Nuclear factor-κB (NF-κB) and activator protein-1 (AP-1) can closely regulate carcinogenesis and thus we analyzed the possible action of FCN may have on these two signaling cascades in tumor cells. The effect of FCN on NF-κB and AP-1 signaling cascades and its downstream functions was deciphered using diverse assays in both human chronic myeloid leukemia (KBM5) and multiple myeloma (U266). FCN attenuated growth of both leukemic and multiple myeloma cells and repressed NF-κB, and AP-1 activation through diverse mechanisms, including attenuation of phosphorylation of IκB kinase (IKK) and p65. Furthermore, FCN could also cause significant enhancement in TNFα-driven apoptosis as studied by various molecular techniques. Thus, FCN may exhibit potent anti-neoplastic effects by affecting diverse oncogenic pathways and may be employed as pro-apoptotic agent against various malignancies.


  • Open Access

    Formononetin Regulates Multiple Oncogenic Signaling Cascades and Enhances Sensitivity to Bortezomib in a Multiple Myeloma Mouse Model

    by Chulwon Kim, Jong Hyun Lee, Jeong-Hyeon Ko, Arunachalam Chinnathambi, Sulaiman Ali Alharbi, Omar H.M. Shair, Gautam Sethi, Kwang Seok Ahn

    Here, we determined the anti-neoplastic actions of formononetin (FT) against multiple myeloma (MM) and elucidated its possible mode of action. It was observed that FT enhanced the apoptosis caused by bortezomib (Bor) and mitigated proliferation in MM cells, and these events are regulated by nuclear factor-κB (NF-κB), phosphatidylinositol 3-kinase (PI3K)/AKT, and activator protein-1 (AP-1) activation. We further noted that FT treatment reduced the levels of diverse tumorigenic proteins involved in myeloma progression and survival. Interestingly, we observed that FT also blocked persistent NF-κB, PI3K/AKT, and AP-1 activation in myeloma cells. FT suppressed the activation of these oncogenic cascades by affecting a number of signaling molecules involved in their cellular regulation. In addition, FT augmented tumor growth-inhibitory potential of Bor in MM preclinical mouse model. Thus, FT can be employed with proteasomal inhibitors for myeloma therapy by regulating the activation of diverse oncogenic transcription factors involved in myeloma growth.