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HER3 as biomarker and therapeutic target in pancreatic cancer: new insights in pertuzumab therapy in preclinical models.

Thomas G, Chardès T, Gaborit N, Mollevi C, Leconet W, Robert B, Radosevic-Robin N, Penault-Llorca F, Gongora C, Colombo PE, Lazrek Y, Bras-Goncalves R, Savina A, Azria D, Bazin H, Pèlegrin A, Larbouret C - Oncotarget (2014)

Bottom Line: We correlated in vitro and in vivo HER3 expression and neuregulin dependency with the inhibitory effect of pertuzumab on cell viability and tumor progression.Finally, HER2 and HER3 were co-expressed in 11% and HER3 alone in 27% of the 45 pancreatic ductal adenocarcinomas analyzed by immunohistochemistry.Further studies in clinical samples are required to confirm these findings and the interest of combining anti-HER2 and anti-HER3 therapeutic antibodies.

View Article: PubMed Central - PubMed

Affiliation: IRCM, Institut de Recherche en Cancérologie de Montpellier, Montpellier, F-34298, France; INSERM, Unit 896, Montpellier, F-34298, France; Université Montpellier1, Montpellier, F-34298, France; ICM, Montpellier, France. Institut Roche de Recherche et Médecine Translationnelle, Boulogne Bilancourt, France.

ABSTRACT
The anti-HER2 antibody pertuzumab inhibits HER2 dimerization and affects HER2/HER3 dimer formation and signaling. As HER3 and its ligand neuregulin are implicated in pancreatic tumorigenesis, we investigated whether HER3 expression could be a predictive biomarker of pertuzumab efficacy in HER2low-expressing pancreatic cancer. We correlated in vitro and in vivo HER3 expression and neuregulin dependency with the inhibitory effect of pertuzumab on cell viability and tumor progression. HER3 knockdown in BxPC-3 cells led to resistance to pertuzumab therapy. Pertuzumab treatment of HER3-expressing pancreatic cancer cells increased HER3 at the cell membrane, whereas the anti-HER3 monoclonal antibody 9F7-F11 down-regulated it. Both antibodies blocked HER3 and AKT phosphorylation and inhibited HER2/HER3 heterodimerization but affected differently HER2 and HER3 homodimers. The pertuzumab/9F7-F11 combination enhanced tumor inhibition and the median survival time in mice xenografted with HER3-expressing pancreatic cancer cells. Finally, HER2 and HER3 were co-expressed in 11% and HER3 alone in 27% of the 45 pancreatic ductal adenocarcinomas analyzed by immunohistochemistry. HER3 is essential for pertuzumab efficacy in HER2low-expressing pancreatic cancer and HER3 expression might be a predictive biomarker of pertuzumab efficacy in such cancers. Further studies in clinical samples are required to confirm these findings and the interest of combining anti-HER2 and anti-HER3 therapeutic antibodies.

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HER3 knockdown abrogates pertuzumab efficacy in BxPC-3 cellsHER3 expression was assessed by western blotting or cytometry [A] in BxPC-3 shHER3 and shCTRL cells. B, shHER3 and shCTRL BxPC-3 cells were serum-starved for 24h and then incubated with NRG1β1 for 5 days (left panel). C, ShHER3 and shCTRL BxPC-3 cells were serum-starved for 24h and then incubated with NRG1β1 and pertuzumab for 5 days (right panel). Cell proliferation was analyzed by MTS. Data are the mean ± SD. Results are expressed as percentage of growth relative to control (untreated cells). *** p < 0.001; n.s., not significant. ShCTRL (D) and shHER3 (E) BxPC-3 cells were xenografted in nude mice that were then treated with 10 mg/kg pertuzumab or sterile PBS twice per week. Results are presented as the mean tumor volume of each group during the treatment and Kaplan-Meier survival curves. Bars = SEM.
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Figure 3: HER3 knockdown abrogates pertuzumab efficacy in BxPC-3 cellsHER3 expression was assessed by western blotting or cytometry [A] in BxPC-3 shHER3 and shCTRL cells. B, shHER3 and shCTRL BxPC-3 cells were serum-starved for 24h and then incubated with NRG1β1 for 5 days (left panel). C, ShHER3 and shCTRL BxPC-3 cells were serum-starved for 24h and then incubated with NRG1β1 and pertuzumab for 5 days (right panel). Cell proliferation was analyzed by MTS. Data are the mean ± SD. Results are expressed as percentage of growth relative to control (untreated cells). *** p < 0.001; n.s., not significant. ShCTRL (D) and shHER3 (E) BxPC-3 cells were xenografted in nude mice that were then treated with 10 mg/kg pertuzumab or sterile PBS twice per week. Results are presented as the mean tumor volume of each group during the treatment and Kaplan-Meier survival curves. Bars = SEM.

Mentions: To further investigate HER3 implication in the response to pertuzumab, we generated a BxPC-3 cell line in which HER3 expression was abrogated by stable knockdown of HER3 by shRNA (shHER3 BxPC-3). BxPC-3 cells that stably express the pSIREN-shLuc vector alone were used as negative control (shCTRL BxPC-3). HER2 expression was not affected and was similar in both cell lines (Figure 3A). The dose-dependent positive effect of NRG1β1 on cell proliferation observed in parental BxPC-3 cells was inhibited in shHER3 BxPC-3 cells, but not in shCTRL BxPC-3 cells (Figure 3B). Treatment with 1 μg/ml pertuzumab significantly inhibited proliferation of NRG1β1-stimulated shCTRL BxPC-3 cells and their viability was reduced by 45% after 5 days (Figure 3C). Conversely, pertuzumab had no significant effect on shHER3 BxPC-3 cell growth (Figure 3C), demonstrating that HER3 knockdown in vitro induces resistance to pertuzumab therapy in pancreatic cancer cells.


HER3 as biomarker and therapeutic target in pancreatic cancer: new insights in pertuzumab therapy in preclinical models.

Thomas G, Chardès T, Gaborit N, Mollevi C, Leconet W, Robert B, Radosevic-Robin N, Penault-Llorca F, Gongora C, Colombo PE, Lazrek Y, Bras-Goncalves R, Savina A, Azria D, Bazin H, Pèlegrin A, Larbouret C - Oncotarget (2014)

HER3 knockdown abrogates pertuzumab efficacy in BxPC-3 cellsHER3 expression was assessed by western blotting or cytometry [A] in BxPC-3 shHER3 and shCTRL cells. B, shHER3 and shCTRL BxPC-3 cells were serum-starved for 24h and then incubated with NRG1β1 for 5 days (left panel). C, ShHER3 and shCTRL BxPC-3 cells were serum-starved for 24h and then incubated with NRG1β1 and pertuzumab for 5 days (right panel). Cell proliferation was analyzed by MTS. Data are the mean ± SD. Results are expressed as percentage of growth relative to control (untreated cells). *** p < 0.001; n.s., not significant. ShCTRL (D) and shHER3 (E) BxPC-3 cells were xenografted in nude mice that were then treated with 10 mg/kg pertuzumab or sterile PBS twice per week. Results are presented as the mean tumor volume of each group during the treatment and Kaplan-Meier survival curves. Bars = SEM.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4196190&req=5

Figure 3: HER3 knockdown abrogates pertuzumab efficacy in BxPC-3 cellsHER3 expression was assessed by western blotting or cytometry [A] in BxPC-3 shHER3 and shCTRL cells. B, shHER3 and shCTRL BxPC-3 cells were serum-starved for 24h and then incubated with NRG1β1 for 5 days (left panel). C, ShHER3 and shCTRL BxPC-3 cells were serum-starved for 24h and then incubated with NRG1β1 and pertuzumab for 5 days (right panel). Cell proliferation was analyzed by MTS. Data are the mean ± SD. Results are expressed as percentage of growth relative to control (untreated cells). *** p < 0.001; n.s., not significant. ShCTRL (D) and shHER3 (E) BxPC-3 cells were xenografted in nude mice that were then treated with 10 mg/kg pertuzumab or sterile PBS twice per week. Results are presented as the mean tumor volume of each group during the treatment and Kaplan-Meier survival curves. Bars = SEM.
Mentions: To further investigate HER3 implication in the response to pertuzumab, we generated a BxPC-3 cell line in which HER3 expression was abrogated by stable knockdown of HER3 by shRNA (shHER3 BxPC-3). BxPC-3 cells that stably express the pSIREN-shLuc vector alone were used as negative control (shCTRL BxPC-3). HER2 expression was not affected and was similar in both cell lines (Figure 3A). The dose-dependent positive effect of NRG1β1 on cell proliferation observed in parental BxPC-3 cells was inhibited in shHER3 BxPC-3 cells, but not in shCTRL BxPC-3 cells (Figure 3B). Treatment with 1 μg/ml pertuzumab significantly inhibited proliferation of NRG1β1-stimulated shCTRL BxPC-3 cells and their viability was reduced by 45% after 5 days (Figure 3C). Conversely, pertuzumab had no significant effect on shHER3 BxPC-3 cell growth (Figure 3C), demonstrating that HER3 knockdown in vitro induces resistance to pertuzumab therapy in pancreatic cancer cells.

Bottom Line: We correlated in vitro and in vivo HER3 expression and neuregulin dependency with the inhibitory effect of pertuzumab on cell viability and tumor progression.Finally, HER2 and HER3 were co-expressed in 11% and HER3 alone in 27% of the 45 pancreatic ductal adenocarcinomas analyzed by immunohistochemistry.Further studies in clinical samples are required to confirm these findings and the interest of combining anti-HER2 and anti-HER3 therapeutic antibodies.

View Article: PubMed Central - PubMed

Affiliation: IRCM, Institut de Recherche en Cancérologie de Montpellier, Montpellier, F-34298, France; INSERM, Unit 896, Montpellier, F-34298, France; Université Montpellier1, Montpellier, F-34298, France; ICM, Montpellier, France. Institut Roche de Recherche et Médecine Translationnelle, Boulogne Bilancourt, France.

ABSTRACT
The anti-HER2 antibody pertuzumab inhibits HER2 dimerization and affects HER2/HER3 dimer formation and signaling. As HER3 and its ligand neuregulin are implicated in pancreatic tumorigenesis, we investigated whether HER3 expression could be a predictive biomarker of pertuzumab efficacy in HER2low-expressing pancreatic cancer. We correlated in vitro and in vivo HER3 expression and neuregulin dependency with the inhibitory effect of pertuzumab on cell viability and tumor progression. HER3 knockdown in BxPC-3 cells led to resistance to pertuzumab therapy. Pertuzumab treatment of HER3-expressing pancreatic cancer cells increased HER3 at the cell membrane, whereas the anti-HER3 monoclonal antibody 9F7-F11 down-regulated it. Both antibodies blocked HER3 and AKT phosphorylation and inhibited HER2/HER3 heterodimerization but affected differently HER2 and HER3 homodimers. The pertuzumab/9F7-F11 combination enhanced tumor inhibition and the median survival time in mice xenografted with HER3-expressing pancreatic cancer cells. Finally, HER2 and HER3 were co-expressed in 11% and HER3 alone in 27% of the 45 pancreatic ductal adenocarcinomas analyzed by immunohistochemistry. HER3 is essential for pertuzumab efficacy in HER2low-expressing pancreatic cancer and HER3 expression might be a predictive biomarker of pertuzumab efficacy in such cancers. Further studies in clinical samples are required to confirm these findings and the interest of combining anti-HER2 and anti-HER3 therapeutic antibodies.

Show MeSH
Related in: MedlinePlus