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Tetrathiomolybdate mediates cisplatin-induced p38 signaling and EGFR degradation and enhances response to cisplatin therapy in gynecologic cancers.

Kim KK, Han A, Yano N, Ribeiro JR, Lokich E, Singh RK, Moore RG - Sci Rep (2015)

Bottom Line: However, TM treatment prior to cisplatin markedly improves cisplatin-induced cytotoxicity.These results are in contrast to what we saw when cells were co-treated with cisplatin plus an EGFR tyrosine kinase inhibitor, where receptor activation was inhibited but receptor degradation was also blocked.We furthermore provide evidence that TM may provide an additional benefit by potentiating p38 activation following cisplatin treatment, which may in turn promote receptor degradation by cisplatin.

View Article: PubMed Central - PubMed

Affiliation: Molecular Therapeutics Laboratory, Program in Women's Oncology, Departments of Obstetrics and Gynecology, Women and Infants Hospital, Alpert Medical School, Brown University, Providence, RI, USA.

ABSTRACT
Cisplatin and its analogs are among the most widely used chemotherapeutic agents against various types of cancer. It is known that cisplatin can activate epidermal growth factor receptor (EGFR), which may provide a survival benefit in cancers. Tetrathiomolybdate (TM) is a potent anti-cancer and anti-angiogenic agent and has been investigated in a number of clinical trials for cancer. In this study, we explore the therapeutic potential of TM on cisplatin-mediated EGFR regulation. Our study shows that TM is not cytotoxic, but exerts an anti-proliferative effect in ECC-1 cells. However, TM treatment prior to cisplatin markedly improves cisplatin-induced cytotoxicity. TM suppressed cisplatin-induced activation of EGFR while potentiating activation of p38; the activation of p38 signaling appeared to promote cisplatin-induced EGFR degradation. These results are in contrast to what we saw when cells were co-treated with cisplatin plus an EGFR tyrosine kinase inhibitor, where receptor activation was inhibited but receptor degradation was also blocked. Our current study is in agreement with previous findings that TM may have a therapeutic benefit by inhibiting EGFR activation. We furthermore provide evidence that TM may provide an additional benefit by potentiating p38 activation following cisplatin treatment, which may in turn promote receptor degradation by cisplatin.

No MeSH data available.


Related in: MedlinePlus

TM pretreatment potentiates cisplatin-mediated p38 activation and EGFR serine phosphorylation.(A) ECC-1 cells were treated with or without TM (30 μM) for 48 h, after which the cells were exposed to cisplatin (30 μM) for the indicated times. The levels of p-p38 or p38 were measured by Western blot analysis. (B) ECC-1 cells were treated with or without TM (30 μM) for 48 h, after which the cells were exposed to vehicle or cisplatin (30 μM) for the indicated times. EGFR phosphorylation was determined by Western blot analysis using site specific antibodies for Tyr-1068 or Ser-1046/7. (C) ECC-1 cells were treated with vehicle, EGF (20 ng/ml, 3 h) or cisplatin (120 μM, 6 h) with or without TM pretreatment (30 μM, 48 h). The levels of EGFR or GAPDH were measured by Western blot analysis.
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f5: TM pretreatment potentiates cisplatin-mediated p38 activation and EGFR serine phosphorylation.(A) ECC-1 cells were treated with or without TM (30 μM) for 48 h, after which the cells were exposed to cisplatin (30 μM) for the indicated times. The levels of p-p38 or p38 were measured by Western blot analysis. (B) ECC-1 cells were treated with or without TM (30 μM) for 48 h, after which the cells were exposed to vehicle or cisplatin (30 μM) for the indicated times. EGFR phosphorylation was determined by Western blot analysis using site specific antibodies for Tyr-1068 or Ser-1046/7. (C) ECC-1 cells were treated with vehicle, EGF (20 ng/ml, 3 h) or cisplatin (120 μM, 6 h) with or without TM pretreatment (30 μM, 48 h). The levels of EGFR or GAPDH were measured by Western blot analysis.

Mentions: Our previous studies have reported that TM treatment in combination with doxorubicin mediates p38 activation in cancer cells3031. Thus, we investigated if TM pretreatment potentiates the activation of p38 caused by cisplatin treatment. As shown (Fig. 5A), cells treated with both TM and cisplatin (7 or 24 h post-treatment) showed a substantial increase in p38 activation compared to those only exposed to cisplatin for the same duration. Interestingly, we found that siRNA-mediated SOD1 knockdown in ECC-1 cells did not potentiate cisplatin-mediated p38 activation (Supplementary Fig. S1), suggesting that TM might regulate p38 by a mechanism independent of SOD1. Next, we investigated if TM potentiates EGFR serine phosphorylation following cisplatin treatment. As expected, cisplatin treatment in ECC-1 cells for 2.5 h clearly induced EGFR tyrosine phosphorylation on Y1068 (Fig. 5B). We observed that TM pretreatment diminishes tyrosine phosphorylation by cisplatin, yet causes the appearance of receptor serine phosphorylation (S1046/7) when compared to cells only exposed to cisplatin for the same duration (2.5 h). The effect of TM on serine phosphorylation was further pronounced after 9 h cisplatin exposure.


Tetrathiomolybdate mediates cisplatin-induced p38 signaling and EGFR degradation and enhances response to cisplatin therapy in gynecologic cancers.

Kim KK, Han A, Yano N, Ribeiro JR, Lokich E, Singh RK, Moore RG - Sci Rep (2015)

TM pretreatment potentiates cisplatin-mediated p38 activation and EGFR serine phosphorylation.(A) ECC-1 cells were treated with or without TM (30 μM) for 48 h, after which the cells were exposed to cisplatin (30 μM) for the indicated times. The levels of p-p38 or p38 were measured by Western blot analysis. (B) ECC-1 cells were treated with or without TM (30 μM) for 48 h, after which the cells were exposed to vehicle or cisplatin (30 μM) for the indicated times. EGFR phosphorylation was determined by Western blot analysis using site specific antibodies for Tyr-1068 or Ser-1046/7. (C) ECC-1 cells were treated with vehicle, EGF (20 ng/ml, 3 h) or cisplatin (120 μM, 6 h) with or without TM pretreatment (30 μM, 48 h). The levels of EGFR or GAPDH were measured by Western blot analysis.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4644948&req=5

f5: TM pretreatment potentiates cisplatin-mediated p38 activation and EGFR serine phosphorylation.(A) ECC-1 cells were treated with or without TM (30 μM) for 48 h, after which the cells were exposed to cisplatin (30 μM) for the indicated times. The levels of p-p38 or p38 were measured by Western blot analysis. (B) ECC-1 cells were treated with or without TM (30 μM) for 48 h, after which the cells were exposed to vehicle or cisplatin (30 μM) for the indicated times. EGFR phosphorylation was determined by Western blot analysis using site specific antibodies for Tyr-1068 or Ser-1046/7. (C) ECC-1 cells were treated with vehicle, EGF (20 ng/ml, 3 h) or cisplatin (120 μM, 6 h) with or without TM pretreatment (30 μM, 48 h). The levels of EGFR or GAPDH were measured by Western blot analysis.
Mentions: Our previous studies have reported that TM treatment in combination with doxorubicin mediates p38 activation in cancer cells3031. Thus, we investigated if TM pretreatment potentiates the activation of p38 caused by cisplatin treatment. As shown (Fig. 5A), cells treated with both TM and cisplatin (7 or 24 h post-treatment) showed a substantial increase in p38 activation compared to those only exposed to cisplatin for the same duration. Interestingly, we found that siRNA-mediated SOD1 knockdown in ECC-1 cells did not potentiate cisplatin-mediated p38 activation (Supplementary Fig. S1), suggesting that TM might regulate p38 by a mechanism independent of SOD1. Next, we investigated if TM potentiates EGFR serine phosphorylation following cisplatin treatment. As expected, cisplatin treatment in ECC-1 cells for 2.5 h clearly induced EGFR tyrosine phosphorylation on Y1068 (Fig. 5B). We observed that TM pretreatment diminishes tyrosine phosphorylation by cisplatin, yet causes the appearance of receptor serine phosphorylation (S1046/7) when compared to cells only exposed to cisplatin for the same duration (2.5 h). The effect of TM on serine phosphorylation was further pronounced after 9 h cisplatin exposure.

Bottom Line: However, TM treatment prior to cisplatin markedly improves cisplatin-induced cytotoxicity.These results are in contrast to what we saw when cells were co-treated with cisplatin plus an EGFR tyrosine kinase inhibitor, where receptor activation was inhibited but receptor degradation was also blocked.We furthermore provide evidence that TM may provide an additional benefit by potentiating p38 activation following cisplatin treatment, which may in turn promote receptor degradation by cisplatin.

View Article: PubMed Central - PubMed

Affiliation: Molecular Therapeutics Laboratory, Program in Women's Oncology, Departments of Obstetrics and Gynecology, Women and Infants Hospital, Alpert Medical School, Brown University, Providence, RI, USA.

ABSTRACT
Cisplatin and its analogs are among the most widely used chemotherapeutic agents against various types of cancer. It is known that cisplatin can activate epidermal growth factor receptor (EGFR), which may provide a survival benefit in cancers. Tetrathiomolybdate (TM) is a potent anti-cancer and anti-angiogenic agent and has been investigated in a number of clinical trials for cancer. In this study, we explore the therapeutic potential of TM on cisplatin-mediated EGFR regulation. Our study shows that TM is not cytotoxic, but exerts an anti-proliferative effect in ECC-1 cells. However, TM treatment prior to cisplatin markedly improves cisplatin-induced cytotoxicity. TM suppressed cisplatin-induced activation of EGFR while potentiating activation of p38; the activation of p38 signaling appeared to promote cisplatin-induced EGFR degradation. These results are in contrast to what we saw when cells were co-treated with cisplatin plus an EGFR tyrosine kinase inhibitor, where receptor activation was inhibited but receptor degradation was also blocked. Our current study is in agreement with previous findings that TM may have a therapeutic benefit by inhibiting EGFR activation. We furthermore provide evidence that TM may provide an additional benefit by potentiating p38 activation following cisplatin treatment, which may in turn promote receptor degradation by cisplatin.

No MeSH data available.


Related in: MedlinePlus