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Wenhsiung Chan - One of the best experts on this subject based on the ideXlab platform.
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anti apoptotic effects of curcumin on photosensitized human epidermal carcinoma A431 Cells
Journal of Cellular Biochemistry, 2004Co-Authors: Wenhsiung ChanAbstract:Photodynamic treatment (PDT) can elicit a diverse range of cellular responses, including apoptotic cell death. Previously, we showed that PDT stimulates caspase-3 activation and subsequent cleavage and activation of p21-activated kinase 2 (PAK2) in human epidermal carcinoma A431 Cells. Curcumin, the yellow pigment of Curcuma longa, is known to have anti-oxidant and anti-inflammatory properties. In the present study, using Rose Bengal (RB) as the photosensitizer, we investigated the effect of curcumin on PDT-induced apoptotic events in human epidermal carcinoma A431 Cells. We report that curcumin prevented PDT-induced JNK activation, mitochondrial release of cytochrome c, caspase-3 activation, and cleavage of PAK2. Using the cell permeable dye DCF-DA as an indicator of reactive oxygen species (ROS) generation, we found that both curcumin and ROS scavengers (i.e., l-histidine, a-tocopherol, mannitol) abolished PDT-stimulated intracellular oxidative stress. Moreover, all these PDT-induced apoptotic changes in Cells could be blocked by singlet oxygen scavengers (i.e., l-histidine, a-tocopherol), but were not affected by the hydroxyl radical scavenger mannitol. In addition, we found that SP600125, a JNK-specific inhibitor, reduced PDT-induced JNK activation as well as caspase-3 activation, indicating that JNK activity is required for PDT-induced caspase activation. Collectively, these results demonstrate that singlet oxygen triggers JNK activation, cytochrome c release, caspase activation and subsequent apoptotic biochemical changes during PDT and show that curcumin is a potent inhibitor for this process.
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curcumin inhibits uv irradiation induced oxidative stress and apoptotic biochemical changes in human epidermoid carcinoma A431 Cells
Journal of Cellular Biochemistry, 2003Co-Authors: Wenhsiung ChanAbstract:Ultraviolet (UV) light is a strong apoptotic trigger that induces caspase-dependent biochemical changes in Cells. Previously we showed that UV irradiation can activate caspase-3, and the subsequent cleavage and activation of p21(Cdc42/Rac)-activated kinase 2 (PAK2) in human epidermoid carcinoma A431 Cells. In this study we demonstrate that curcumin (Cur), the yellow pigment of Curcuma longa with known anti-oxidant and anti-inflammatory properties, can prevent UV irradiation-induced apoptotic changes, including c-Jun N-terminal kinase (JNK) activation, loss of mitochondrial membrane potential (MMP), mitochondrial release of cytochrome C, caspase-3 activation, and cleavage/activation of PAK2 in A431 Cells. Flow cytometric analysis using the cell permeable dye 2',7'-dichlorofluorescin diacetate (DCF-DA) as an indicator of reactive oxygen species (ROS) generation revealed that the increase in intracellular oxidative stress caused by UV irradiation could be abolished by Cur. In addition, we found that SP600125, a JNK-specific inhibitor, reduced UV irradiation-induced JNK activation as well as caspase-3 activation, indicating that JNK activity is required for UV irradiation-induced caspase activation. Collectively, our results demonstrate that Cur significantly attenuates UV irradiation-induced ROS formation, and suggest that ROS triggers JNK activation, which in turn causes MMP change, cytochrome C release, caspase activation, and subsequent apoptotic biochemical changes.
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apoptotic signalling cascade in photosensitized human epidermal carcinoma A431 Cells involvement of singlet oxygen c jun n terminal kinase caspase 3 and p21 activated kinase 2
Biochemical Journal, 2000Co-Authors: Wenhsiung Chan, Jausong Yu, Shiawder YangAbstract:Photodynamic treatment (PDT) elicits diverse cellular responses and can also cause apoptosis. In the present study the cascade of signalling events involved in PDT-induced apoptosis was investigated using Rose Bengal (RB) as the photosensitizer, and human epidermal carcinoma A431 Cells as the cell model. We show that a 36-kDa kinase detected by an in-gel kinase assay is markedly activated during PDT-triggered apoptosis. Immunoblot analysis revealed that this 36-kDa kinase represents the C-terminal catalytic fragment of p21-activated kinase (PAK)2. Generation of this active fragment of PAK2 is mediated by the caspase family of proteases, which are activated by PDT. The specific caspase inhibitors (acetyl-Asp-Glu-Val-Asp-aldehyde and acetyl-Tyr-Val-Ala-Asp-chloromethylketone) block the PDT-induced caspase-3 activation and subsequent PAK2 cleavage/activation, indicating a major role for the caspase family proteases in PDT-induced apoptosis. Both PDT-induced caspase-3 activation and PAK2 cleavage/activation can be inhibited by the singlet oxygen scavengers, L-histidine and α-tocopherol, but not the hydroxyl radical scavenger, mannitol, demonstrating that singlet oxygen is an immediate early-apoptotic signal generated by PDT. In addition, PDT can induce a two-stage activation of the c-Jun N-terminal kinase/stress-activated protein kinase (JNK/SAPK) in A431 Cells; the early-stage JNK activation is singlet oxygen-dependent, whereas the late-stage JNK activation is mediated by the singlet oxygen-triggered caspase activation. Experiments using anti-sense oligonucleotides against JNK1 and PAK2 further show that during PDT-induced apoptosis the early-stage JNK activation is required for caspase activation, and that the late-stage JNK activation is regulated by the caspase-mediated cleavage/activation of PAK2. Collectively, a model for the PDT-triggered apoptotic signalling cascade with RB is proposed, which involves singlet oxygen, JNK, caspase-3 and PAK2, sequentially.
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inhibition of uv irradiation induced oxidative stress and apoptotic biochemical changes in human epidermal carcinoma A431 Cells by genistein
Journal of Cellular Biochemistry, 2000Co-Authors: Wenhsiung ChanAbstract:Ultraviolet (UV) light is a strong apoptotic trigger that can induce a caspase-dependent biochemical change in Cells. We previously showed that UV irradiation can elicit caspase-3 activation and the subsequent cleavage and activation of p21-activated kinase 2 (PAK2) in human epidermal carcinoma A431 Cells. We report that genistein, an isoflavone compound with known inhibitory activities to protein tyrosine kinases (PTKs) and topoisomerase-II (topo-II), can prevent UV irradiation-induced apoptotic biochemical changes (DNA fragmentation, caspase-3 activation, and cleavage/activation of PAK2) in A431 Cells. Surprisingly, two typical PTK inhibitors (tyrphostin A47 and herbimycin A) and three known topo-II inhibitors (etoposide, daunorubicin, and novomycin) had no effect on UV irradiation-induced apoptotic biochemical changes, suggesting that the inhibitory effect of genistein is not dependent on its property as a PTK/topo-II inhibitor. In contrast, azide, a reactive oxygen species (ROS) scavenger, could effectively block the UV irradiation-induced apoptotic cell responses. Flow cytometric analysis using the cell-permeable dye 2',7'-dichlorofluorescin diacetate as an indicator of the generation of ROS showed that UV irradiation caused increase of the intracellular oxidative stress and that this increase could be abolished by azide, suggesting that oxidative stress plays an important role in mediating the apoptotic effect of UV irradiation. Importantly, the UV irradiation-induced oxidative stress in Cells could be significantly attenuated by genistein, suggesting that impairment of ROS formation during UV irradiation is responsible for the antiapoptotic effect of genistein. Collectively, our results demonstrate the involvement of oxidative stress in the UV irradiation-induced caspase activation and the subsequent apoptotic biochemical changes and show that genistein is a potent inhibitor for this process.
Hasan Mukhtar - One of the best experts on this subject based on the ideXlab platform.
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resveratrol causes waf 1 p21 mediated g1 phase arrest of cell cycle and induction of apoptosis in human epidermoid carcinoma A431 Cells
Clinical Cancer Research, 2001Co-Authors: Nihal Ahmad, Farrukh Afaq, Vaqar M. Adhami, Denise K Feyes, Hasan MukhtarAbstract:Resveratrol ( trans -3,4′,5,-trihydroxystilbene), a phytoalexin found in grapes, nuts, fruits, and red wine, is a potent antioxidant with cancer-preventive properties. The mechanism by which resveratrol imparts cancer chemopreventive effects is not clearly defined. Here, we demonstrate that resveratrol, via modulations in cyclin-dependent kinase (cdk) inhibitor-cyclin-cdk machinery, results in a G 1 -phase arrest of the cell cycle followed by apoptosis of human epidermoid carcinoma (A431) Cells. Resveratrol treatment (1–50 μm for 24 h) of A431 Cells resulted in a dose-dependent ( a ) inhibition of cell growth as shown by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, ( b ) G 1 -phase arrest of the cell cycle as shown by DNA cell cycle analysis, and ( c ) induction of apoptosis as assessed by ELISA. The immunoblot analysis revealed that resveratrol treatment causes a dose- and time-dependent ( a ) induction of WAF1/p21; ( b ) decrease in the protein expressions of cyclin D1, cyclin D2, and cyclin E; and ( c ) decrease in the protein expressions of cdk2, cdk4, and cdk6. Resveratrol treatment was also found to result in a dose- and time-dependent decrease in kinase activities associated with all of the cdks examined. Taken together, our study suggests that resveratrol treatment of the Cells causes an induction of WAF1/p21 that inhibits cyclin D1/D2-cdk6, cyclin D1/D2-cdk4, and cyclin E-cdk2 complexes, thereby imposing an artificial checkpoint at the G 1 →S transition of the cell cycle. This series of events results in a G 1 -phase arrest of the cell cycle, which is an irreversible process that ultimately results in the apoptotic death of cancer Cells. To our knowledge, this is the first systematic study showing the involvement of each component of cdk inhibitor-cyclin-cdk machinery during cell cycle arrest and apoptosis of cancer Cells by resveratrol.
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Resveratrol causes WAF-1/p21-mediated G(1)-phase arrest of cell cycle and induction of apoptosis in human epidermoid carcinoma A431 Cells.
Clinical cancer research : an official journal of the American Association for Cancer Research, 2001Co-Authors: Nihal Ahmad, Farrukh Afaq, Vaqar M. Adhami, Denise K Feyes, Hasan MukhtarAbstract:Resveratrol (trans-3,4',5,-trihydroxystilbene), a phytoalexin found in grapes, nuts, fruits, and red wine, is a potent antioxidant with cancer-preventive properties. The mechanism by which resveratrol imparts cancer chemopreventive effects is not clearly defined. Here, we demonstrate that resveratrol, via modulations in cyclin-dependent kinase (cdk) inhibitor-cyclin-cdk machinery, results in a G(1)-phase arrest of the cell cycle followed by apoptosis of human epidermoid carcinoma (A431) Cells. Resveratrol treatment (1-50 microM for 24 h) of A431 Cells resulted in a dose-dependent (a) inhibition of cell growth as shown by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, (b) G(1)-phase arrest of the cell cycle as shown by DNA cell cycle analysis, and (c) induction of apoptosis as assessed by ELISA. The immunoblot analysis revealed that resveratrol treatment causes a dose- and time-dependent (a) induction of WAF1/p21; (b) decrease in the protein expressions of cyclin D1, cyclin D2, and cyclin E; and (c) decrease in the protein expressions of cdk2, cdk4, and cdk6. Resveratrol treatment was also found to result in a dose- and time-dependent decrease in kinase activities associated with all of the cdks examined. Taken together, our study suggests that resveratrol treatment of the Cells causes an induction of WAF1/p21 that inhibits cyclin D1/D2-cdk6, cyclin D1/D2-cdk4, and cyclin E-cdk2 complexes, thereby imposing an artificial checkpoint at the G(1)-->S transition of the cell cycle. This series of events results in a G(1)-phase arrest of the cell cycle, which is an irreversible process that ultimately results in the apoptotic death of cancer Cells. To our knowledge, this is the first systematic study showing the involvement of each component of cdk inhibitor-cyclin-cdk machinery during cell cycle arrest and apoptosis of cancer Cells by resveratrol.
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involvement of fas apo 1 cd 95 during photodynamic therapy mediated apoptosis in human epidermoid carcinoma A431 Cells
Journal of Investigative Dermatology, 2000Co-Authors: Nihal Ahmad, Denise K Feyes, Sanjay Gupta, Hasan MukhtarAbstract:Photodynamic therapy is a promising treatment modality for a variety of cutaneous neoplasms and other skin disorders. Studies suggest an involvement of multiple pathways during photodynamic-therapy-mediated cell death. A complete knowledge of the mechanisms involved in photodynamic therapy may lead to an improvement in its therapeutic efficacy. In vitro as well as in vivo studies have shown the involvement of apoptosis during photodynamic- therapy-mediated cell death. The pathways by which photodynamic therapy causes this are not fully understood. In this study, employing human epidermoid carcinoma (A431) Cells and silicon phthalocyanine 4 photodynamic therapy, we show that the cell surface death receptor Fas (also known as APO-1 or CD-95) pathway is an important contributor to photodynamic-therapy-mediated apoptosis. Employ- ing flow cytometric analysis and confocal microscopy we first established that silicon phthalocyanine 4 photodynamic therapy results in a significant induc- tion of apoptosis in A431 Cells. Immunoblot analysis revealed a significant time-dependent increase in the protein expression of Fas at 5, 15, 30, and 60 min post-photodynamic therapy followed by a decrease at later time-points (2 and 3 h post-photodynamic therapy). A Fas enzyme-linked immunosorbent assay demonstrated an increase in this protein in cell culture medium starting at 1 h post-photodynamic therapy and showing a time-dependent response up to 3 h following therapy, suggesting a diffusion of soluble Fas from Cells into the medium from 1 h after photodynamic therapy. Silicon phthalocyanine 4 photodynamic therapy also resulted in a time-dependent increase in (i) the multimerization of Fas protein, (ii) the protein expression of Fas ligand, (iii) FADD, an adapter molecule for Fas, and (iv) the binding of FADD with Fas. Silicon phthalocyanine 4 photodynamic therapy also caused a significant activation of FLICE, as evident from the appearance of cleaved products of pro-caspase 8. Further, a pretreatment of Cells with rhFas:Fc fusion protein or general caspase inhibitor Z-VAD-FMK followed by silicon phthalocyanine 4 photodynamic therapy resulted in a significantly enhanced cell survival. Taken together, our data, for the first time, delineate an involvement of the Fas pathway as an important contributor to photodynamic-therapy-mediated apoptosis of cancer Cells. These observations may be important for improving the efficacy of photodynamic therapy for the treatment of skin cancer and possibly other skin disorders.
Santosh K Katiyar - One of the best experts on this subject based on the ideXlab platform.
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grape seed proanthocyanidins promote apoptosis in human epidermoid carcinoma A431 Cells through alterations in cdki cdk cyclin cascade and caspase 3 activation via loss of mitochondrial membrane potential
Experimental Dermatology, 2007Co-Authors: Syed Musthapa Meeran, Santosh K KatiyarAbstract:: Dietary grape seed proanthocyanidins (GSPs) prevent photocarcinogenesis in mice. Here, we report that in vitro treatment of human epidermoid carcinoma A431 Cells with GSPs inhibited cellular proliferation (13-89%) and induced cell death (1-48%) in a dose (5-100 mug/ml)- and time (24, 48 and 72 h)-dependent manner. GSP-induced inhibition of cell proliferation was associated with an increase in G1-phase arrest at 24 h, which was mediated through the inhibition of cyclin-dependent kinases (Cdk) Cdk2, Cdk4, Cdk6 and cyclins D1, D2 and E and simultaneous increase in protein expression of cyclin-dependent kinase inhibitors (Cdki), Cip1/p21 and Kip1/p27, and enhanced binding of Cdki-Cdk. The treatment of A431 Cells with GSPs (20-80 mug/ml) resulted in a dose-dependent increase in apoptotic cell death (26-58%), which was associated with an increased protein expression of proapoptotic Bax, decreased expression of antiapoptotic Bcl-2 and Bcl-xl, loss of mitochondrial membrane potential, and cleavage of caspase-9, caspase-3 and PARP. Pretreatment with the pan-caspase inhibitor (z-VAD-fmk) blocked the GSP-induced apoptosis in A431 Cells suggesting that GSP-induced apoptosis is associated primarily with the caspase-3-dependent pathway. Together, our study suggests that GSPs possess chemotherapeutic potential against human epidermoid carcinoma Cells in vitro, further in vivo mechanistic studies are required to verify the chemotherapeutic effect of GSPs in skin cancers.
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berberine inhibits growth induces g1 arrest and apoptosis in human epidermoid carcinoma A431 Cells by regulating cdki cdk cyclin cascade disruption of mitochondrial membrane potential and cleavage of caspase 3 and parp
Carcinogenesis, 2006Co-Authors: Sudheer K Mantena, Som D Sharma, Santosh K KatiyarAbstract:Chemotherapeutic approach using non-toxic botanicals may be one of the strategies for the management of the skin cancers. Here we report that in vitro treatment of human epidermoid carcinoma A431 Cells with berberine, a naturally occurring isoquinoline alkaloid, decreased cell viability (3–77%, P < 0.05–0.001) and induced cell death (3–51%, P < 0.01–0.001) in a dose (5–75 mM)- and time (12–72 h)-dependent manner, which was associated with an increase in G1 arrest. G0/G1 phase of the cell cycle is known to be controlled by cyclin dependent kinases (Cdk), cyclin kinase inhibitors (Cdki) and cyclins. Our western blot analysis showed that berberine-induced G1 cell cycle arrest was mediated through the increased expression of Cdki proteins (Cip1/p21 and Kip1/p27), a simultaneous decrease in Cdk2, Cdk4, Cdk6 and cyclins D1, D2 and E and enhanced binding of Cdki–Cdk. In additional studies, treatment of A431 Cells with berberine (15–75 mM) for 72 h resulted in a significant dose-dependent increase in apoptosis (31–60%, P < 0.05–0.001) than non-berberinetreated control (11.7%), which was associated with an increased expression of pro-apoptotic protein Bax, decreased expression of anti-apoptotic proteins Bcl-2 and Bcl-xl, disruption of mitochondrial membrane potential, and activation of caspases 9, 3 and poly (ADP-ribose) polymerase. Pretreatment of A431 Cells with the pan-caspase inhibitor (z-VAD-fmk) significantly blocked the berberine-induced apoptosis in A431 Cells confirmed that berberine-induced apoptosis is mediated through activation of caspase 3dependent pathway. Together, this study for the first time identified berberine as a chemotherapeutic agent against human epidermoid carcinoma A431 Cells in vitro, further in vivo studies are required to determine whether berberine could be an effective chemotherapeutic agent for the management of non-melanoma skin cancers.
Nihal Ahmad - One of the best experts on this subject based on the ideXlab platform.
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involvement of the retinoblastoma prb e2f dp pathway during antiproliferative effects of resveratrol in human epidermoid carcinoma A431 Cells
Biochemical and Biophysical Research Communications, 2001Co-Authors: Vaqar M. Adhami, Farrukh Afaq, Nihal AhmadAbstract:Resveratrol (trans-3,4′,5-trihydroxystilbene), a polyphenolic phytoalexin found in grapes, nuts, many other fruits, and red wine, is a potent antioxidant with anti-inflammatory and cancer-preventive properties. The mechanism(s) by which resveratrol imparts cancer chemopreventive effects has not been clearly defined. Earlier, we have shown that resveratrol treatment results in an induction of the cyclin kinase inhibitor WAF1/CIP1/p21 which, by inhibiting cyclin (E, D1, and D2) and cyclin-dependent kinases (cdk2, cdk4, and cdk6), results in a G0/G1-phase arrest followed by apoptosis of A431 human epidermoid carcinoma Cells (Ahmad et al., Clin. Cancer Res. 7, 1466–1473, 2001). Retinoblastoma (pRb) and the E2F family of transcription factors are important proteins, which regulate the progression of the cell cycle at and near the G1→S phase transition. Here we provide evidence for the involvement of the pRb–E2F/DP pathway as an important contributor of resveratrol-mediated cell cycle arrest and apoptosis. Immunoblot analysis demonstrated that resveratrol treatment of A431 Cells results in a dose- as well as time-dependent decrease in the hyperphosphorylated form of pRb with a relative increase in hypophosphorylated pRb. This response was accompanied by downregulation of protein expression of all five E2F (1–5) family members of transcription factors studied and their heterodimeric partners DP1 and DP2. This suggests that resveratrol causes a downregulation of hyperphosphorylated pRb protein with a relative increase in hypophosphorylated pRb that, in turn, compromises with the availability of free E2F. We suggest that this series of events results in a stoppage of the cell cycle progression at the G1→S phase transition thereby leading to a G0/G1 arrest and subsequent apoptotic cell death. To our knowledge, this is the first study showing the involvement of the pRb–E2F/DP pathway as a mechanism of the cancer-chemopreventive effects of resveratrol.
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resveratrol causes waf 1 p21 mediated g1 phase arrest of cell cycle and induction of apoptosis in human epidermoid carcinoma A431 Cells
Clinical Cancer Research, 2001Co-Authors: Nihal Ahmad, Farrukh Afaq, Vaqar M. Adhami, Denise K Feyes, Hasan MukhtarAbstract:Resveratrol ( trans -3,4′,5,-trihydroxystilbene), a phytoalexin found in grapes, nuts, fruits, and red wine, is a potent antioxidant with cancer-preventive properties. The mechanism by which resveratrol imparts cancer chemopreventive effects is not clearly defined. Here, we demonstrate that resveratrol, via modulations in cyclin-dependent kinase (cdk) inhibitor-cyclin-cdk machinery, results in a G 1 -phase arrest of the cell cycle followed by apoptosis of human epidermoid carcinoma (A431) Cells. Resveratrol treatment (1–50 μm for 24 h) of A431 Cells resulted in a dose-dependent ( a ) inhibition of cell growth as shown by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, ( b ) G 1 -phase arrest of the cell cycle as shown by DNA cell cycle analysis, and ( c ) induction of apoptosis as assessed by ELISA. The immunoblot analysis revealed that resveratrol treatment causes a dose- and time-dependent ( a ) induction of WAF1/p21; ( b ) decrease in the protein expressions of cyclin D1, cyclin D2, and cyclin E; and ( c ) decrease in the protein expressions of cdk2, cdk4, and cdk6. Resveratrol treatment was also found to result in a dose- and time-dependent decrease in kinase activities associated with all of the cdks examined. Taken together, our study suggests that resveratrol treatment of the Cells causes an induction of WAF1/p21 that inhibits cyclin D1/D2-cdk6, cyclin D1/D2-cdk4, and cyclin E-cdk2 complexes, thereby imposing an artificial checkpoint at the G 1 →S transition of the cell cycle. This series of events results in a G 1 -phase arrest of the cell cycle, which is an irreversible process that ultimately results in the apoptotic death of cancer Cells. To our knowledge, this is the first systematic study showing the involvement of each component of cdk inhibitor-cyclin-cdk machinery during cell cycle arrest and apoptosis of cancer Cells by resveratrol.
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Resveratrol causes WAF-1/p21-mediated G(1)-phase arrest of cell cycle and induction of apoptosis in human epidermoid carcinoma A431 Cells.
Clinical cancer research : an official journal of the American Association for Cancer Research, 2001Co-Authors: Nihal Ahmad, Farrukh Afaq, Vaqar M. Adhami, Denise K Feyes, Hasan MukhtarAbstract:Resveratrol (trans-3,4',5,-trihydroxystilbene), a phytoalexin found in grapes, nuts, fruits, and red wine, is a potent antioxidant with cancer-preventive properties. The mechanism by which resveratrol imparts cancer chemopreventive effects is not clearly defined. Here, we demonstrate that resveratrol, via modulations in cyclin-dependent kinase (cdk) inhibitor-cyclin-cdk machinery, results in a G(1)-phase arrest of the cell cycle followed by apoptosis of human epidermoid carcinoma (A431) Cells. Resveratrol treatment (1-50 microM for 24 h) of A431 Cells resulted in a dose-dependent (a) inhibition of cell growth as shown by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, (b) G(1)-phase arrest of the cell cycle as shown by DNA cell cycle analysis, and (c) induction of apoptosis as assessed by ELISA. The immunoblot analysis revealed that resveratrol treatment causes a dose- and time-dependent (a) induction of WAF1/p21; (b) decrease in the protein expressions of cyclin D1, cyclin D2, and cyclin E; and (c) decrease in the protein expressions of cdk2, cdk4, and cdk6. Resveratrol treatment was also found to result in a dose- and time-dependent decrease in kinase activities associated with all of the cdks examined. Taken together, our study suggests that resveratrol treatment of the Cells causes an induction of WAF1/p21 that inhibits cyclin D1/D2-cdk6, cyclin D1/D2-cdk4, and cyclin E-cdk2 complexes, thereby imposing an artificial checkpoint at the G(1)-->S transition of the cell cycle. This series of events results in a G(1)-phase arrest of the cell cycle, which is an irreversible process that ultimately results in the apoptotic death of cancer Cells. To our knowledge, this is the first systematic study showing the involvement of each component of cdk inhibitor-cyclin-cdk machinery during cell cycle arrest and apoptosis of cancer Cells by resveratrol.
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involvement of fas apo 1 cd 95 during photodynamic therapy mediated apoptosis in human epidermoid carcinoma A431 Cells
Journal of Investigative Dermatology, 2000Co-Authors: Nihal Ahmad, Denise K Feyes, Sanjay Gupta, Hasan MukhtarAbstract:Photodynamic therapy is a promising treatment modality for a variety of cutaneous neoplasms and other skin disorders. Studies suggest an involvement of multiple pathways during photodynamic-therapy-mediated cell death. A complete knowledge of the mechanisms involved in photodynamic therapy may lead to an improvement in its therapeutic efficacy. In vitro as well as in vivo studies have shown the involvement of apoptosis during photodynamic- therapy-mediated cell death. The pathways by which photodynamic therapy causes this are not fully understood. In this study, employing human epidermoid carcinoma (A431) Cells and silicon phthalocyanine 4 photodynamic therapy, we show that the cell surface death receptor Fas (also known as APO-1 or CD-95) pathway is an important contributor to photodynamic-therapy-mediated apoptosis. Employ- ing flow cytometric analysis and confocal microscopy we first established that silicon phthalocyanine 4 photodynamic therapy results in a significant induc- tion of apoptosis in A431 Cells. Immunoblot analysis revealed a significant time-dependent increase in the protein expression of Fas at 5, 15, 30, and 60 min post-photodynamic therapy followed by a decrease at later time-points (2 and 3 h post-photodynamic therapy). A Fas enzyme-linked immunosorbent assay demonstrated an increase in this protein in cell culture medium starting at 1 h post-photodynamic therapy and showing a time-dependent response up to 3 h following therapy, suggesting a diffusion of soluble Fas from Cells into the medium from 1 h after photodynamic therapy. Silicon phthalocyanine 4 photodynamic therapy also resulted in a time-dependent increase in (i) the multimerization of Fas protein, (ii) the protein expression of Fas ligand, (iii) FADD, an adapter molecule for Fas, and (iv) the binding of FADD with Fas. Silicon phthalocyanine 4 photodynamic therapy also caused a significant activation of FLICE, as evident from the appearance of cleaved products of pro-caspase 8. Further, a pretreatment of Cells with rhFas:Fc fusion protein or general caspase inhibitor Z-VAD-FMK followed by silicon phthalocyanine 4 photodynamic therapy resulted in a significantly enhanced cell survival. Taken together, our data, for the first time, delineate an involvement of the Fas pathway as an important contributor to photodynamic-therapy-mediated apoptosis of cancer Cells. These observations may be important for improving the efficacy of photodynamic therapy for the treatment of skin cancer and possibly other skin disorders.
Chandradhar Dwivedi - One of the best experts on this subject based on the ideXlab platform.
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alpha santalol a chemopreventive agent against skin cancer causes g2 m cell cycle arrest in both p53 mutated human epidermoid carcinoma A431 Cells and p53 wild type human melanoma uacc 62 Cells
BMC Research Notes, 2010Co-Authors: Xiaoying Zhang, Wei Chen, Radhey S Kaushik, Hesham Fahmy, Ruth Guillermo, Gudiseva Chandrasekher, Alan Young, Chandradhar DwivediAbstract:Background α-Santalol, an active component of sandalwood oil, has shown chemopreventive effects on skin cancer in different murine models. However, effects of α-santalol on cell cycle have not been studied. Thus, the objective of this study was to investigate effects of α-santalol on cell cycle progression in both p53 mutated human epidermoid carcinoma A431 Cells and p53 wild-type human melanoma UACC-62 Cells to elucidate the mechanism(s) of action.
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sarcophine diol a chemopreventive agent of skin cancer inhibits cell growth and induces apoptosis through extrinsic pathway in human epidermoid carcinoma A431 Cells
Translational Oncology, 2009Co-Authors: Xiaoying Zhang, Ajay Bommareddy, Wei Chen, Sherief Khalifa, Radhey S Kaushik, Hesham Fahmy, Chandradhar DwivediAbstract:Sarcophine-diol (SD), a structural modifications of sarcophine, has shown chemopreventive effects on 7,12-dimethylbenz(a)anthracene-initiated and 12-O-tetradecanoylphorbol-13-acetate-promoted skin tumor developments in mice. Tumorigenesis is associated with uncontrolled cell growth and loss of apoptosis. In the present study, the effects of SD on cell growth and apoptosis in human epidermoid carcinoma A431 Cells were determined to assess whether SD could inhibit cell growth and/or induce apoptosis, thus elucidating possible mechanism of action. MTT assay was used for cell viability; bromodeoxyuridine incorporation assay was used for cell proliferation; fluorescence-activated cell sorting analysis of annexin V/propidium iodide staining and TUNEL assay were used for determining apoptotic Cells; Western blot analysis was used for determining the expression of caspase-3 and colorimetric caspase activity assays were used for determination of caspase-3, -8, and -9 activity. The results showed that SD treatment at concentration of 200 to 600 µM resulted in a concentration-dependent decrease in cell viability and cell proliferation in A431 Cells, which largely inhibited cell growth. Sarcophine-diol treatment induced a strong apoptosis and significantly (P < .05) increased DNA fragmentation in A431 Cells. Furthermore, SD treatment significantly (P < .05) increased the activity and expression of caspase-3 through activation of upstream caspase-8 in A431 Cells rather than the activation of caspase 9. Sarcophine-diol treatment is relatively much less cytotoxic in monkey kidney normal CV-1 Cells. These results suggest that SD decreases cell growth and induces apoptosis through caspase-dependent extrinsic pathway in A431 Cells, and this may contribute to its overall chemopreventive effects in mouse skin cancer models.
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skin cancer chemopreventive agent α santalol induces apoptotic death of human epidermoid carcinoma A431 Cells via caspase activation together with dissipation of mitochondrial membrane potential and cytochrome c release
Carcinogenesis, 2004Co-Authors: Manjinder Kaur, Chandradhar Dwivedi, Rana P Singh, Chapla Agarwal, Xiangming Guan, Rajesh AgarwalAbstract:alpha-Santalol, an active component of sandalwood oil, has been studied in detail in recent years for its skin cancer preventive efficacy in murine models of skin carcinogenesis; however, the mechanism of its efficacy is not defined. Two major biological events responsible for the clonal expansion of transformed/initiated Cells into tumors are uncontrolled growth and loss of apoptotic death. Accordingly, in the present study, employing human epidermoid carcinoma A431 Cells, we assessed whether alpha-santalol causes cell growth inhibition and/or cell death by apoptosis. Treatment of Cells with alpha-santalol at concentrations of 25-75 microM resulted in a concentration- and a time-dependent decrease in cell number, which was largely due to cell death. Fluorescence-activated cell sorting analysis of Annexin V/propidium iodide (PI) stained Cells revealed that alpha-santalol induces a strong apoptosis as early as 3 h post-treatment, which increases further in a concentration- and a time-dependent manner up to 12 h. Mechanistic studies showed an involvement of caspase-3 activation and poly(ADP-ribose) polymerase cleavage through activation of upstream caspase-8 and -9. Further, the treatment of Cells with alpha-santalol also led to disruption of the mitochondrial membrane potential and cytochrome c release into the cytosol, thereby implicating the involvement of the mitochondrial pathway. Pre-treatment of Cells with caspase-8 or -9 inhibitor, pan caspase inhibitor or cycloheximide totally blocked alpha-santalol-caused caspase-3 activity and cleavage, but only partially reversed apoptotic cell death. This suggests involvement of both caspase-dependent and -independent pathways, at least under caspase inhibiting conditions, in alpha-santalol-caused apoptosis. Together, this study for the first time identifies the apoptotic effect of alpha-santalol, and defines the mechanism of apoptotic cascade activated by this agent in A431 Cells, which might be contributing to its overall cancer preventive efficacy in mouse skin cancer models.
