Limits...
Shikonin selectively induces apoptosis in human prostate cancer cells through the endoplasmic reticulum stress and mitochondrial apoptotic pathway.

Gara RK, Srivastava VK, Duggal S, Bagga JK, Bhatt M, Sanyal S, Mishra DP - J. Biomed. Sci. (2015)

Bottom Line: Moreover, addition of antioxidants attenuated these effects.Shikonin also induced the mitochondrial apoptotic pathway mediated through the enhanced expression of the pro-apoptotic Bax and inhibition of Bcl-2, disruption of the mitochondrial membrane potential (MMP) followed by the activation of caspase-9, caspase-3, and PARP cleavage.The results suggest that shikonin could be useful in the therapeutic management of hormone refractory prostate cancers due to its modulation of the pro-apoptotic ER stress and mitochondrial apoptotic pathways.

View Article: PubMed Central - PubMed

Affiliation: Cell Death Research Laboratory, Endocrinology Division CSIR-Central Drug Research Institute, Lucknow, 226031, India. rgara@uthsc.edu.

ABSTRACT

Background: Despite the recent progress in screening and therapy, a majority of prostate cancer cases eventually attain hormone refractory and chemo-resistant attributes. Conventional chemotherapeutic strategies are effective at very high doses for only palliative management of these prostate cancers. Therefore chemo-sensitization of prostate cancer cells could be a promising strategy for increasing efficacy of the conventional chemotherapeutic agents in prostate cancer patients. Recent studies have indicated that the chemo-preventive natural agents restore the pro-apoptotic protein expression and induce endoplasmic reticulum stress (ER stress) leading to the inhibition of cellular proliferation and activation of the mitochondrial apoptosis in prostate cancer cells. Therefore reprogramming ER stress-mitochondrial dependent apoptosis could be a potential approach for management of hormone refractory chemoresistant prostate cancers. We aimed to study the effects of the natural naphthoquinone Shikonin in human prostate cancer cells.

Results: The results indicated that Shikonin induces apoptosis in prostate cancer cells through the dual induction of the endoplasmic reticulum stress and mitochondrial dysfunction. Shikonin induced ROS generation and activated ER stress and calpain activity. Moreover, addition of antioxidants attenuated these effects. Shikonin also induced the mitochondrial apoptotic pathway mediated through the enhanced expression of the pro-apoptotic Bax and inhibition of Bcl-2, disruption of the mitochondrial membrane potential (MMP) followed by the activation of caspase-9, caspase-3, and PARP cleavage.

Conclusion: The results suggest that shikonin could be useful in the therapeutic management of hormone refractory prostate cancers due to its modulation of the pro-apoptotic ER stress and mitochondrial apoptotic pathways.

No MeSH data available.


Related in: MedlinePlus

Induction of ER stress is critical in Shikonin induced effects in DU-145 and PC-3 prostate cancer cells (A) Effect of Solubrinal or BAPTA on ER stress protein expression in DU-145 and PC-3 cells. Protein expression of ER-stress was examined in pre-treated with BAPTA or Salubrinal in DU-145 and PC-3 cells, and western blot experiments were performed as described previously. (B) Inhibition of intracellular calcium or calpain reveses shikonin induced inhibition of cell viability. Cell viability was quantified using the CCK-8 assay in BAPTA or Calpeptin pretreated DU-145 and PC-3 cells. Data is expressed in means ± SEM and represents the results of three independent experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
getmorefigures.php?uid=PMC4389804&req=5

Fig5: Induction of ER stress is critical in Shikonin induced effects in DU-145 and PC-3 prostate cancer cells (A) Effect of Solubrinal or BAPTA on ER stress protein expression in DU-145 and PC-3 cells. Protein expression of ER-stress was examined in pre-treated with BAPTA or Salubrinal in DU-145 and PC-3 cells, and western blot experiments were performed as described previously. (B) Inhibition of intracellular calcium or calpain reveses shikonin induced inhibition of cell viability. Cell viability was quantified using the CCK-8 assay in BAPTA or Calpeptin pretreated DU-145 and PC-3 cells. Data is expressed in means ± SEM and represents the results of three independent experiments.

Mentions: We next assessed the expression of ER stress proteins as many studies have implicated the interplay between, ROS, mitochondria, intracellular Ca2+ and calpain activity determines ER stress and cell survival in cancer cells [32-34]. The results indicated that pretreatment with the Ca2+ chelator, BAPTA or the ER stress inhibitor Salubrinal inhibited the shikonin induced expression of p-pERK, p-pelF2α, CHOP/GADD153 and caspase 4 activity (Figure 5A). Furthermore, our cell proliferation data in presence of BAPTA (a Ca2+ chelator) or calpeptin (a calpain inhibitor) for 1h, also confirmed that Shikonin mediated cell death involves calcium signaling in prostate cancer DU-145 and PC-3 cells (Figure 5B).Figure 5


Shikonin selectively induces apoptosis in human prostate cancer cells through the endoplasmic reticulum stress and mitochondrial apoptotic pathway.

Gara RK, Srivastava VK, Duggal S, Bagga JK, Bhatt M, Sanyal S, Mishra DP - J. Biomed. Sci. (2015)

Induction of ER stress is critical in Shikonin induced effects in DU-145 and PC-3 prostate cancer cells (A) Effect of Solubrinal or BAPTA on ER stress protein expression in DU-145 and PC-3 cells. Protein expression of ER-stress was examined in pre-treated with BAPTA or Salubrinal in DU-145 and PC-3 cells, and western blot experiments were performed as described previously. (B) Inhibition of intracellular calcium or calpain reveses shikonin induced inhibition of cell viability. Cell viability was quantified using the CCK-8 assay in BAPTA or Calpeptin pretreated DU-145 and PC-3 cells. Data is expressed in means ± SEM and represents the results of three independent experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4389804&req=5

Fig5: Induction of ER stress is critical in Shikonin induced effects in DU-145 and PC-3 prostate cancer cells (A) Effect of Solubrinal or BAPTA on ER stress protein expression in DU-145 and PC-3 cells. Protein expression of ER-stress was examined in pre-treated with BAPTA or Salubrinal in DU-145 and PC-3 cells, and western blot experiments were performed as described previously. (B) Inhibition of intracellular calcium or calpain reveses shikonin induced inhibition of cell viability. Cell viability was quantified using the CCK-8 assay in BAPTA or Calpeptin pretreated DU-145 and PC-3 cells. Data is expressed in means ± SEM and represents the results of three independent experiments.
Mentions: We next assessed the expression of ER stress proteins as many studies have implicated the interplay between, ROS, mitochondria, intracellular Ca2+ and calpain activity determines ER stress and cell survival in cancer cells [32-34]. The results indicated that pretreatment with the Ca2+ chelator, BAPTA or the ER stress inhibitor Salubrinal inhibited the shikonin induced expression of p-pERK, p-pelF2α, CHOP/GADD153 and caspase 4 activity (Figure 5A). Furthermore, our cell proliferation data in presence of BAPTA (a Ca2+ chelator) or calpeptin (a calpain inhibitor) for 1h, also confirmed that Shikonin mediated cell death involves calcium signaling in prostate cancer DU-145 and PC-3 cells (Figure 5B).Figure 5

Bottom Line: Moreover, addition of antioxidants attenuated these effects.Shikonin also induced the mitochondrial apoptotic pathway mediated through the enhanced expression of the pro-apoptotic Bax and inhibition of Bcl-2, disruption of the mitochondrial membrane potential (MMP) followed by the activation of caspase-9, caspase-3, and PARP cleavage.The results suggest that shikonin could be useful in the therapeutic management of hormone refractory prostate cancers due to its modulation of the pro-apoptotic ER stress and mitochondrial apoptotic pathways.

View Article: PubMed Central - PubMed

Affiliation: Cell Death Research Laboratory, Endocrinology Division CSIR-Central Drug Research Institute, Lucknow, 226031, India. rgara@uthsc.edu.

ABSTRACT

Background: Despite the recent progress in screening and therapy, a majority of prostate cancer cases eventually attain hormone refractory and chemo-resistant attributes. Conventional chemotherapeutic strategies are effective at very high doses for only palliative management of these prostate cancers. Therefore chemo-sensitization of prostate cancer cells could be a promising strategy for increasing efficacy of the conventional chemotherapeutic agents in prostate cancer patients. Recent studies have indicated that the chemo-preventive natural agents restore the pro-apoptotic protein expression and induce endoplasmic reticulum stress (ER stress) leading to the inhibition of cellular proliferation and activation of the mitochondrial apoptosis in prostate cancer cells. Therefore reprogramming ER stress-mitochondrial dependent apoptosis could be a potential approach for management of hormone refractory chemoresistant prostate cancers. We aimed to study the effects of the natural naphthoquinone Shikonin in human prostate cancer cells.

Results: The results indicated that Shikonin induces apoptosis in prostate cancer cells through the dual induction of the endoplasmic reticulum stress and mitochondrial dysfunction. Shikonin induced ROS generation and activated ER stress and calpain activity. Moreover, addition of antioxidants attenuated these effects. Shikonin also induced the mitochondrial apoptotic pathway mediated through the enhanced expression of the pro-apoptotic Bax and inhibition of Bcl-2, disruption of the mitochondrial membrane potential (MMP) followed by the activation of caspase-9, caspase-3, and PARP cleavage.

Conclusion: The results suggest that shikonin could be useful in the therapeutic management of hormone refractory prostate cancers due to its modulation of the pro-apoptotic ER stress and mitochondrial apoptotic pathways.

No MeSH data available.


Related in: MedlinePlus