Curcumin induces tumor necrosis factor-alpha treated HaCaT cells to apoptosis

【摘要】：Psoriasis is a benign,chronic skin disease characterized by keratinocyte hyperproliferation and abnormal differentiation.Curcumin,a selective phosphorylase kinase inhibitor,is a natural phytochemical present in turmeric.Curcumin has been affirmed to have anti-inflammatory property and ability to curtail the proliferation and decrease the expression of proinflammatory cytokines in psoriatic keratinocytes.Unfortunately,the pro-apoptotic effect of curcumin in keratinocytes remains unclear.In the preset study,we investigated the effect of curcumin inducing TNF-α treated HaCaT cells to apoptosis.The results showed that curcumin exhibited a significant pro-apoptosis effect in HaCaT cells only in the presence of TNF-α and/or TRAIL.The pro-apoptotic effect of curcumin was through enhancing the expression of TRAIL-R1/R2 and inhibiting the expression of anti-apoptotic proteins.It was found that both curcumin and TNF-α up-regulated the expression of TRAIL-R1/R2.In addition,the expression of anti-apoptotic proteins (IAP1,IAP2,Bcl-X L) was up-regulated by TNF-α but suppressed by curcumin in HaCaT cells.Knowing that these gene products are regulated by NF-κB,we examined the role of curcumin in NF-κB activation.As expected,curcumin was able to inhibit TNF-α-induced activation of NF-κB including NF-κB-P65.Curcumin also inhibited the TNF-α induced production of IL-6/IL-8 in HaCaT cells.These results imply curcumin particularly induce apoptosis of HaCaT cells when TNF-α or TRAIL exist.We therefore believe that curcumin were able to reversed TNF-α induced anti-apoptotic feature in HaCaT cells;and expect a promising future of curcumin in the treatment of psoriasis.