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Expression of HER-2 affects patient survival and paclitaxel sensitivity in endometrial cancer.

Mori N, Kyo S, Nakamura M, Hashimoto M, Maida Y, Mizumoto Y, Takakura M, Ohno S, Kiyono T, Inoue M - Br. J. Cancer (2010)

Bottom Line: Kaplan-Meier analysis revealed that high HER-2 expression was a factor that negatively influenced the progression-free and overall survival rate (P<0.05), and multivariate analysis showed high HER-2 expression to be an independent prognostic factor.Subsequently, we performed in vitro knockdown analysis to investigate the linkage between HER-2 expression and PI3K-AKT pathways.As the PI3K-AKT pathway is known to have crucial roles in anticancer drug sensitivity, we examined the involvement of HER-2 in sensitivity to paclitaxel.

View Article: PubMed Central - PubMed

Affiliation: Department of Obstetrics and Gynecology, Kanazawa University Graduate School of Medical Science, 13-1 Takaramachi, Kanazawa, Ishikawa 920-8641, Japan.

ABSTRACT

Background: Disabled phosphatidylinositol 3-kinase (PI3K)/AKT and mitogen-activated protein kinase/extracellular signal-regulated kinase signalling is involved in endometrial carcinogenesis, and there is evidence that expression of epidermal growth factor receptor (EGFR) family members has a role in such intracellular signalling pathways. This study analysed the prognostic impact of EGFR family expression in endometrial cancer in relation to PI3K-AKT and MAPK-ERK signalling, as well as drug sensitivity.

Methods and results: Immunohistochemical analysis using 63 surgical specimens of endometrioid-type endometrial cancers revealed that EGFR, human epidermal growth factor receptor (HER)-2 and HER-4 were expressed in 25 (39.7%) of 63, 26 (41.3%) of 63 and 31 (49.2%) of 63 tumours, respectively. Gene amplification of HER-2 was observed in 2 of 26 patients with high HER-2 expression. Kaplan-Meier analysis revealed that high HER-2 expression was a factor that negatively influenced the progression-free and overall survival rate (P<0.05), and multivariate analysis showed high HER-2 expression to be an independent prognostic factor. Subsequently, we performed in vitro knockdown analysis to investigate the linkage between HER-2 expression and PI3K-AKT pathways. Short interfering RNA (siRNA)-based knockdown of HER-2 in endometrial cancer cells led to a significant reduction in phosphorylated AKT (p-AKT) expression, indicating the existence of a HER-2/PI3K-AKT axis. As the PI3K-AKT pathway is known to have crucial roles in anticancer drug sensitivity, we examined the involvement of HER-2 in sensitivity to paclitaxel. Short interfering RNA-based knockdown of HER-2 conferred increased sensitivity to paclitaxel in endometrial cancer cells, attenuating the induction of p-AKT on paclitaxel stimulation, which was cancelled by inactivating AKT by the introduction of a dominant-negative form.

Conclusion: HER-2 is a significant prognostic factor of endometrioid-type endometrial cancer, as well as a key molecule that affects paclitaxel sensitivity by HER-2 interaction with the PI3K-AKT pathway.

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Linkage between HER-2 and p-AKT expressions in endometrial cancer or immortalised cells. Endometrial cancer Ishikawa and HEC1A cells or endometrial immortalised EM-E6/E7/TERT cells were treated with or without siRNA against HER-2. After 48 h, cell lysates were prepared and western blot analyses were performed with antibodies against HER-2, p-AKT and total AKT. NC: negative control sample treated with scrambled siRNA.
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fig3: Linkage between HER-2 and p-AKT expressions in endometrial cancer or immortalised cells. Endometrial cancer Ishikawa and HEC1A cells or endometrial immortalised EM-E6/E7/TERT cells were treated with or without siRNA against HER-2. After 48 h, cell lysates were prepared and western blot analyses were performed with antibodies against HER-2, p-AKT and total AKT. NC: negative control sample treated with scrambled siRNA.

Mentions: The above findings indicate that HER-2 expression is a critical prognostic factor in endometrial cancer. We next sought to identify the downstream target of HER-2 expression using various endometrial cancer cell lines or immortalised endometrial epithelial cells (EM-E6/E7/TERT). One possible candidate for a downstream target of HER-2 was the PI3K–AKT pathway, based on previous analyses in other tumour types (Knuefermann et al, 2003; Qi et al, 2009); hence, we focused on this pathway. To examine the linkage between HER-2 and the PI3K–AKT pathway, a knockdown of HER-2 was performed in the endometrial cancer cell line Ishikawa, using siRNA techniques, and the expression of p-AKT was evaluated by western blot analysis. As shown in Figure 3, knockdown of HER-2 was confirmed to be efficient, with a more than 50% reduction in expression. Notably, p-AKT expression concomitantly decreased with HER-2 knockdown. This finding was not limited to Ishikawa cells, as both endometrial cancer HEC1A cells and EM-E6/E7/TERT cells exhibited a similar decrease in p-AKT expression on HER-2 knockdown (Figure 3). Thus, the HER-2 pathway clearly links to the PI3K–AKT pathway in endometrial cancer cells.


Expression of HER-2 affects patient survival and paclitaxel sensitivity in endometrial cancer.

Mori N, Kyo S, Nakamura M, Hashimoto M, Maida Y, Mizumoto Y, Takakura M, Ohno S, Kiyono T, Inoue M - Br. J. Cancer (2010)

Linkage between HER-2 and p-AKT expressions in endometrial cancer or immortalised cells. Endometrial cancer Ishikawa and HEC1A cells or endometrial immortalised EM-E6/E7/TERT cells were treated with or without siRNA against HER-2. After 48 h, cell lysates were prepared and western blot analyses were performed with antibodies against HER-2, p-AKT and total AKT. NC: negative control sample treated with scrambled siRNA.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2966616&req=5

fig3: Linkage between HER-2 and p-AKT expressions in endometrial cancer or immortalised cells. Endometrial cancer Ishikawa and HEC1A cells or endometrial immortalised EM-E6/E7/TERT cells were treated with or without siRNA against HER-2. After 48 h, cell lysates were prepared and western blot analyses were performed with antibodies against HER-2, p-AKT and total AKT. NC: negative control sample treated with scrambled siRNA.
Mentions: The above findings indicate that HER-2 expression is a critical prognostic factor in endometrial cancer. We next sought to identify the downstream target of HER-2 expression using various endometrial cancer cell lines or immortalised endometrial epithelial cells (EM-E6/E7/TERT). One possible candidate for a downstream target of HER-2 was the PI3K–AKT pathway, based on previous analyses in other tumour types (Knuefermann et al, 2003; Qi et al, 2009); hence, we focused on this pathway. To examine the linkage between HER-2 and the PI3K–AKT pathway, a knockdown of HER-2 was performed in the endometrial cancer cell line Ishikawa, using siRNA techniques, and the expression of p-AKT was evaluated by western blot analysis. As shown in Figure 3, knockdown of HER-2 was confirmed to be efficient, with a more than 50% reduction in expression. Notably, p-AKT expression concomitantly decreased with HER-2 knockdown. This finding was not limited to Ishikawa cells, as both endometrial cancer HEC1A cells and EM-E6/E7/TERT cells exhibited a similar decrease in p-AKT expression on HER-2 knockdown (Figure 3). Thus, the HER-2 pathway clearly links to the PI3K–AKT pathway in endometrial cancer cells.

Bottom Line: Kaplan-Meier analysis revealed that high HER-2 expression was a factor that negatively influenced the progression-free and overall survival rate (P<0.05), and multivariate analysis showed high HER-2 expression to be an independent prognostic factor.Subsequently, we performed in vitro knockdown analysis to investigate the linkage between HER-2 expression and PI3K-AKT pathways.As the PI3K-AKT pathway is known to have crucial roles in anticancer drug sensitivity, we examined the involvement of HER-2 in sensitivity to paclitaxel.

View Article: PubMed Central - PubMed

Affiliation: Department of Obstetrics and Gynecology, Kanazawa University Graduate School of Medical Science, 13-1 Takaramachi, Kanazawa, Ishikawa 920-8641, Japan.

ABSTRACT

Background: Disabled phosphatidylinositol 3-kinase (PI3K)/AKT and mitogen-activated protein kinase/extracellular signal-regulated kinase signalling is involved in endometrial carcinogenesis, and there is evidence that expression of epidermal growth factor receptor (EGFR) family members has a role in such intracellular signalling pathways. This study analysed the prognostic impact of EGFR family expression in endometrial cancer in relation to PI3K-AKT and MAPK-ERK signalling, as well as drug sensitivity.

Methods and results: Immunohistochemical analysis using 63 surgical specimens of endometrioid-type endometrial cancers revealed that EGFR, human epidermal growth factor receptor (HER)-2 and HER-4 were expressed in 25 (39.7%) of 63, 26 (41.3%) of 63 and 31 (49.2%) of 63 tumours, respectively. Gene amplification of HER-2 was observed in 2 of 26 patients with high HER-2 expression. Kaplan-Meier analysis revealed that high HER-2 expression was a factor that negatively influenced the progression-free and overall survival rate (P<0.05), and multivariate analysis showed high HER-2 expression to be an independent prognostic factor. Subsequently, we performed in vitro knockdown analysis to investigate the linkage between HER-2 expression and PI3K-AKT pathways. Short interfering RNA (siRNA)-based knockdown of HER-2 in endometrial cancer cells led to a significant reduction in phosphorylated AKT (p-AKT) expression, indicating the existence of a HER-2/PI3K-AKT axis. As the PI3K-AKT pathway is known to have crucial roles in anticancer drug sensitivity, we examined the involvement of HER-2 in sensitivity to paclitaxel. Short interfering RNA-based knockdown of HER-2 conferred increased sensitivity to paclitaxel in endometrial cancer cells, attenuating the induction of p-AKT on paclitaxel stimulation, which was cancelled by inactivating AKT by the introduction of a dominant-negative form.

Conclusion: HER-2 is a significant prognostic factor of endometrioid-type endometrial cancer, as well as a key molecule that affects paclitaxel sensitivity by HER-2 interaction with the PI3K-AKT pathway.

Show MeSH
Related in: MedlinePlus