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Perhexiline promotes HER3 ablation through receptor internalization and inhibits tumor growth.

Ren XR, Wang J, Osada T, Mook RA, Morse MA, Barak LS, Lyerly HK, Chen W - Breast Cancer Res. (2015)

Bottom Line: Thus, agents that reduce HER3 expression at the plasma membrane may synergize with current therapies and offer a novel therapeutic strategy to improve treatment.In vitro and in vivo tumor models were used to characterize the signaling effects of perhexiline, an anti-anginal drug, identified by the screening platform.We found perhexiline, an anti-anginal drug, selectively internalized HER3, decreased HER3 expression, and subsequently inhibited signaling downstream of HER3.

View Article: PubMed Central - PubMed

ABSTRACT

Introduction: Human epidermal growth factor receptor HER3 has been implicated in promoting the aggressiveness and metastatic potential of breast cancer. Upregulation of HER3 has been found to be a major mechanism underlying drug resistance to EGFR and HER2 tyrosine kinase inhibitors and to endocrine therapy in the treatment of breast cancer. Thus, agents that reduce HER3 expression at the plasma membrane may synergize with current therapies and offer a novel therapeutic strategy to improve treatment.

Methods: We devised an image-based screening platform using membrane localized HER3-YFP to identify small molecules that promote HER3 internalization and degradation. In vitro and in vivo tumor models were used to characterize the signaling effects of perhexiline, an anti-anginal drug, identified by the screening platform.

Results: We found perhexiline, an anti-anginal drug, selectively internalized HER3, decreased HER3 expression, and subsequently inhibited signaling downstream of HER3. Consistent with these results, perhexiline inhibited breast cancer cell proliferation in vitro and tumor growth in vivo.

Conclusions: This is the first demonstration that HER3 can be targeted with small molecules by eliminating it from the cell membrane. The novel approach used here led to the discovery that perhexiline ablates HER3 expression, and offers an opportunity to identify HER3 ablation modulators as innovative therapeutics to improve survival in breast cancer patients.

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Related in: MedlinePlus

Perhexiline inhibits the tumorigenesis of MDA-MB-468 cells in NOD/SCID mice. (A) MDA-MB-468 cells (1 × 106/mouse) were injected to the flank of SCID mice on day 0. On day 7, oral gavage treatment with perhexiline (0, 400 mg/kg) was initiated, and repeated for 5 days a week for 4 weeks. Tumor diameter was measured every 3 to 4 days. Each group consisted of five mice. Date represent mean ± SEM (n = 5, *P <0.05 by a two-tailed Student’s t test). (B) The body weight was measured at the same time of tumor measurement. Each group consisted of five mice. Data represent mean ± SEM (n = 5, *P <0.05 by a two-tailed Student’s t test). (C) Tumor samples were collected from all five mice in the control and perhexiline-treated group and processed for Western blotting analysis. The level of phospho-HER3 was detected using the phospho-Tyr1289 antibody. β-actin was used as a loading control. (D) Quantitative representation of p-HER3 levels. Western blots shown in (C) were quantified by normalizing to β-actin. Data represent mean ± SEM (n = 5, *P <0.05 by a two-tailed Student’s t test compared to the control group). HER3, human epidermal growth factor receptor 3; SEM, standard error of the mean.
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Fig5: Perhexiline inhibits the tumorigenesis of MDA-MB-468 cells in NOD/SCID mice. (A) MDA-MB-468 cells (1 × 106/mouse) were injected to the flank of SCID mice on day 0. On day 7, oral gavage treatment with perhexiline (0, 400 mg/kg) was initiated, and repeated for 5 days a week for 4 weeks. Tumor diameter was measured every 3 to 4 days. Each group consisted of five mice. Date represent mean ± SEM (n = 5, *P <0.05 by a two-tailed Student’s t test). (B) The body weight was measured at the same time of tumor measurement. Each group consisted of five mice. Data represent mean ± SEM (n = 5, *P <0.05 by a two-tailed Student’s t test). (C) Tumor samples were collected from all five mice in the control and perhexiline-treated group and processed for Western blotting analysis. The level of phospho-HER3 was detected using the phospho-Tyr1289 antibody. β-actin was used as a loading control. (D) Quantitative representation of p-HER3 levels. Western blots shown in (C) were quantified by normalizing to β-actin. Data represent mean ± SEM (n = 5, *P <0.05 by a two-tailed Student’s t test compared to the control group). HER3, human epidermal growth factor receptor 3; SEM, standard error of the mean.

Mentions: The antitumor effect of perhexiline was then studied in vivo. Triple-negative MDA-MB-468 cells were inoculated subcutaneously into SCID mice and 7 days later, oral gavage perhexiline was initiated and dosed five times a week. As shown in Figure 5A, perhexiline significantly inhibited the growth of MDA-MB-468 tumors. During the course of the treatment with perhexiline, no obvious side effects such as body weight loss were observed in the treated mice (Figure 5B). In addition, tumor masses were excised, homogenized, and immune-blotted for the expression of phosphorylated HER3. Perhexiline-treated tumors showed significantly decreased levels of phosphorylated HER3 compared to control tumors (Figure 5C-D). Taken together, these results indicated that perhexiline inhibits tumor growth and HER3 signaling in vivo.Figure 5


Perhexiline promotes HER3 ablation through receptor internalization and inhibits tumor growth.

Ren XR, Wang J, Osada T, Mook RA, Morse MA, Barak LS, Lyerly HK, Chen W - Breast Cancer Res. (2015)

Perhexiline inhibits the tumorigenesis of MDA-MB-468 cells in NOD/SCID mice. (A) MDA-MB-468 cells (1 × 106/mouse) were injected to the flank of SCID mice on day 0. On day 7, oral gavage treatment with perhexiline (0, 400 mg/kg) was initiated, and repeated for 5 days a week for 4 weeks. Tumor diameter was measured every 3 to 4 days. Each group consisted of five mice. Date represent mean ± SEM (n = 5, *P <0.05 by a two-tailed Student’s t test). (B) The body weight was measured at the same time of tumor measurement. Each group consisted of five mice. Data represent mean ± SEM (n = 5, *P <0.05 by a two-tailed Student’s t test). (C) Tumor samples were collected from all five mice in the control and perhexiline-treated group and processed for Western blotting analysis. The level of phospho-HER3 was detected using the phospho-Tyr1289 antibody. β-actin was used as a loading control. (D) Quantitative representation of p-HER3 levels. Western blots shown in (C) were quantified by normalizing to β-actin. Data represent mean ± SEM (n = 5, *P <0.05 by a two-tailed Student’s t test compared to the control group). HER3, human epidermal growth factor receptor 3; SEM, standard error of the mean.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
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getmorefigures.php?uid=PMC4358700&req=5

Fig5: Perhexiline inhibits the tumorigenesis of MDA-MB-468 cells in NOD/SCID mice. (A) MDA-MB-468 cells (1 × 106/mouse) were injected to the flank of SCID mice on day 0. On day 7, oral gavage treatment with perhexiline (0, 400 mg/kg) was initiated, and repeated for 5 days a week for 4 weeks. Tumor diameter was measured every 3 to 4 days. Each group consisted of five mice. Date represent mean ± SEM (n = 5, *P <0.05 by a two-tailed Student’s t test). (B) The body weight was measured at the same time of tumor measurement. Each group consisted of five mice. Data represent mean ± SEM (n = 5, *P <0.05 by a two-tailed Student’s t test). (C) Tumor samples were collected from all five mice in the control and perhexiline-treated group and processed for Western blotting analysis. The level of phospho-HER3 was detected using the phospho-Tyr1289 antibody. β-actin was used as a loading control. (D) Quantitative representation of p-HER3 levels. Western blots shown in (C) were quantified by normalizing to β-actin. Data represent mean ± SEM (n = 5, *P <0.05 by a two-tailed Student’s t test compared to the control group). HER3, human epidermal growth factor receptor 3; SEM, standard error of the mean.
Mentions: The antitumor effect of perhexiline was then studied in vivo. Triple-negative MDA-MB-468 cells were inoculated subcutaneously into SCID mice and 7 days later, oral gavage perhexiline was initiated and dosed five times a week. As shown in Figure 5A, perhexiline significantly inhibited the growth of MDA-MB-468 tumors. During the course of the treatment with perhexiline, no obvious side effects such as body weight loss were observed in the treated mice (Figure 5B). In addition, tumor masses were excised, homogenized, and immune-blotted for the expression of phosphorylated HER3. Perhexiline-treated tumors showed significantly decreased levels of phosphorylated HER3 compared to control tumors (Figure 5C-D). Taken together, these results indicated that perhexiline inhibits tumor growth and HER3 signaling in vivo.Figure 5

Bottom Line: Thus, agents that reduce HER3 expression at the plasma membrane may synergize with current therapies and offer a novel therapeutic strategy to improve treatment.In vitro and in vivo tumor models were used to characterize the signaling effects of perhexiline, an anti-anginal drug, identified by the screening platform.We found perhexiline, an anti-anginal drug, selectively internalized HER3, decreased HER3 expression, and subsequently inhibited signaling downstream of HER3.

View Article: PubMed Central - PubMed

ABSTRACT

Introduction: Human epidermal growth factor receptor HER3 has been implicated in promoting the aggressiveness and metastatic potential of breast cancer. Upregulation of HER3 has been found to be a major mechanism underlying drug resistance to EGFR and HER2 tyrosine kinase inhibitors and to endocrine therapy in the treatment of breast cancer. Thus, agents that reduce HER3 expression at the plasma membrane may synergize with current therapies and offer a novel therapeutic strategy to improve treatment.

Methods: We devised an image-based screening platform using membrane localized HER3-YFP to identify small molecules that promote HER3 internalization and degradation. In vitro and in vivo tumor models were used to characterize the signaling effects of perhexiline, an anti-anginal drug, identified by the screening platform.

Results: We found perhexiline, an anti-anginal drug, selectively internalized HER3, decreased HER3 expression, and subsequently inhibited signaling downstream of HER3. Consistent with these results, perhexiline inhibited breast cancer cell proliferation in vitro and tumor growth in vivo.

Conclusions: This is the first demonstration that HER3 can be targeted with small molecules by eliminating it from the cell membrane. The novel approach used here led to the discovery that perhexiline ablates HER3 expression, and offers an opportunity to identify HER3 ablation modulators as innovative therapeutics to improve survival in breast cancer patients.

Show MeSH
Related in: MedlinePlus