Limits...
Combined Treatment with Exendin-4 and Metformin Attenuates Prostate Cancer Growth.

Tsutsumi Y, Nomiyama T, Kawanami T, Hamaguchi Y, Terawaki Y, Tanaka T, Murase K, Motonaga R, Tanabe M, Yanase T - PLoS ONE (2015)

Bottom Line: Recently, the pleiotropic benefits of incretin-based therapy have been reported.Metformin is known for its anti-cancer effect.In vivo, Exendin-4 and metformin significantly decreased tumor size, and further significant tumor size reduction was observed after combined treatment.

View Article: PubMed Central - PubMed

Affiliation: Department of Endocrinology and Diabetes Mellitus, School of Medicine, Fukuoka University, 7-45-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan.

ABSTRACT

Introduction: Recently, the pleiotropic benefits of incretin-based therapy have been reported. We have previously reported that Exendin-4, a glucagon-like peptide-1 (GLP-1) receptor agonist, attenuates prostate cancer growth. Metformin is known for its anti-cancer effect. Here, we examined the anti-cancer effect of Exendin-4 and metformin using a prostate cancer model.

Methods: Prostate cancer cells were treated with Exendin-4 and/or metformin. Cell proliferation was quantified by growth curves and 5-bromo-2'-deoxyuridine (BrdU) assay. TUNEL assay and AMP-activated protein kinase (AMPK) phosphorylation were examined in LNCaP cells. For in vivo experiments, LNCaP cells were transplanted subcutaneously into the flank region of athymic mice, which were then treated with Exendin-4 and/or metformin. TUNEL assay and immunohistochemistry were performed on tumors.

Results: Exendin-4 and metformin additively decreased the growth curve, but not the migration, of prostate cancer cells. The BrdU assay revealed that both Exendin-4 and metformin significantly decreased prostate cancer cell proliferation. Furthermore, metformin, but not Exendin-4, activated AMPK and induced apoptosis in LNCaP cells. The anti-proliferative effect of metformin was abolished by inhibition or knock down of AMPK. In vivo, Exendin-4 and metformin significantly decreased tumor size, and further significant tumor size reduction was observed after combined treatment. Immunohistochemistry on tumors revealed that the P504S and Ki67 expression decreased by Exendin-4 and/or metformin, and that metformin increased phospho-AMPK expression and the apoptotic cell number.

Conclusion: These data suggest that Exendin-4 and metformin attenuated prostate cancer growth by inhibiting proliferation, and that metformin inhibited proliferation by inducing apoptosis. Combined treatment with Exendin-4 and metformin attenuated prostate cancer growth more than separate treatments.

No MeSH data available.


Related in: MedlinePlus

Exendin–4 and metformin decrease the number of Ki67 and P504S-positive cells, and increase GLP-1R expression.Paraffin-embedded tumor sections (5 μm) were subjected to immunohistochemistry for (A) Ki67, (C) P504S and GLP-1R, and (F) AR, and counterstained with DAPI. Magnification, ×400. (B) Ki67, (D) P504S, (E) GLP-1R, and (G) AR-positive cells were quantified by analyzing the fraction of stained cells in the tumor relative to the total number of nuclei. Values are expressed as a percentage of positive cells. Unpaired t-tests were performed to calculate statistical significance (*P < 0.05, **P < 0.01 vs. control).
© Copyright Policy
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4595004&req=5

pone.0139709.g002: Exendin–4 and metformin decrease the number of Ki67 and P504S-positive cells, and increase GLP-1R expression.Paraffin-embedded tumor sections (5 μm) were subjected to immunohistochemistry for (A) Ki67, (C) P504S and GLP-1R, and (F) AR, and counterstained with DAPI. Magnification, ×400. (B) Ki67, (D) P504S, (E) GLP-1R, and (G) AR-positive cells were quantified by analyzing the fraction of stained cells in the tumor relative to the total number of nuclei. Values are expressed as a percentage of positive cells. Unpaired t-tests were performed to calculate statistical significance (*P < 0.05, **P < 0.01 vs. control).

Mentions: Immunohistochemical analysis of paraffin-embedded sections of subcutaneous prostate cancer tumors demonstrated that Ki67 expression, which was clearly localized within the nucleus, was significantly suppressed by Ex–4, metformin and the combined treatment (Fig 2A and 2B). However, an additional decrease in Ki67-positive cells was not observed in the combined treatment group compared with the separate treatments. The expression of P504S, a prostate cancer marker, dramatically decreased by Ex–4, metformin and the combined treatment (Fig 2C). Quantification of P504S expression based on the mean number of P504S-positive cells divided by the total number of nuclei confirmed that there was a significant reduction in cancerous cells after Ex–4, metformin and the combined treatment (Fig 2D). Interestingly, the number of prostate cancer cells expressing GLP-1R increased after Ex–4 and/or metformin treatment (Fig 2C). Quantification of the proportion GLP-1R-positive cells revealed that the combined treatment significantly increased the number of GLP-1R-positive cells compared with the control (Fig 2E). Furthermore, we detected AR-positive cells in the prostate cancer tumor (Fig 2F). No change was observed in AR expression after Ex–4 and metformin treatment in the prostate cancer tumor (Fig 2G).


Combined Treatment with Exendin-4 and Metformin Attenuates Prostate Cancer Growth.

Tsutsumi Y, Nomiyama T, Kawanami T, Hamaguchi Y, Terawaki Y, Tanaka T, Murase K, Motonaga R, Tanabe M, Yanase T - PLoS ONE (2015)

Exendin–4 and metformin decrease the number of Ki67 and P504S-positive cells, and increase GLP-1R expression.Paraffin-embedded tumor sections (5 μm) were subjected to immunohistochemistry for (A) Ki67, (C) P504S and GLP-1R, and (F) AR, and counterstained with DAPI. Magnification, ×400. (B) Ki67, (D) P504S, (E) GLP-1R, and (G) AR-positive cells were quantified by analyzing the fraction of stained cells in the tumor relative to the total number of nuclei. Values are expressed as a percentage of positive cells. Unpaired t-tests were performed to calculate statistical significance (*P < 0.05, **P < 0.01 vs. control).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4595004&req=5

pone.0139709.g002: Exendin–4 and metformin decrease the number of Ki67 and P504S-positive cells, and increase GLP-1R expression.Paraffin-embedded tumor sections (5 μm) were subjected to immunohistochemistry for (A) Ki67, (C) P504S and GLP-1R, and (F) AR, and counterstained with DAPI. Magnification, ×400. (B) Ki67, (D) P504S, (E) GLP-1R, and (G) AR-positive cells were quantified by analyzing the fraction of stained cells in the tumor relative to the total number of nuclei. Values are expressed as a percentage of positive cells. Unpaired t-tests were performed to calculate statistical significance (*P < 0.05, **P < 0.01 vs. control).
Mentions: Immunohistochemical analysis of paraffin-embedded sections of subcutaneous prostate cancer tumors demonstrated that Ki67 expression, which was clearly localized within the nucleus, was significantly suppressed by Ex–4, metformin and the combined treatment (Fig 2A and 2B). However, an additional decrease in Ki67-positive cells was not observed in the combined treatment group compared with the separate treatments. The expression of P504S, a prostate cancer marker, dramatically decreased by Ex–4, metformin and the combined treatment (Fig 2C). Quantification of P504S expression based on the mean number of P504S-positive cells divided by the total number of nuclei confirmed that there was a significant reduction in cancerous cells after Ex–4, metformin and the combined treatment (Fig 2D). Interestingly, the number of prostate cancer cells expressing GLP-1R increased after Ex–4 and/or metformin treatment (Fig 2C). Quantification of the proportion GLP-1R-positive cells revealed that the combined treatment significantly increased the number of GLP-1R-positive cells compared with the control (Fig 2E). Furthermore, we detected AR-positive cells in the prostate cancer tumor (Fig 2F). No change was observed in AR expression after Ex–4 and metformin treatment in the prostate cancer tumor (Fig 2G).

Bottom Line: Recently, the pleiotropic benefits of incretin-based therapy have been reported.Metformin is known for its anti-cancer effect.In vivo, Exendin-4 and metformin significantly decreased tumor size, and further significant tumor size reduction was observed after combined treatment.

View Article: PubMed Central - PubMed

Affiliation: Department of Endocrinology and Diabetes Mellitus, School of Medicine, Fukuoka University, 7-45-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan.

ABSTRACT

Introduction: Recently, the pleiotropic benefits of incretin-based therapy have been reported. We have previously reported that Exendin-4, a glucagon-like peptide-1 (GLP-1) receptor agonist, attenuates prostate cancer growth. Metformin is known for its anti-cancer effect. Here, we examined the anti-cancer effect of Exendin-4 and metformin using a prostate cancer model.

Methods: Prostate cancer cells were treated with Exendin-4 and/or metformin. Cell proliferation was quantified by growth curves and 5-bromo-2'-deoxyuridine (BrdU) assay. TUNEL assay and AMP-activated protein kinase (AMPK) phosphorylation were examined in LNCaP cells. For in vivo experiments, LNCaP cells were transplanted subcutaneously into the flank region of athymic mice, which were then treated with Exendin-4 and/or metformin. TUNEL assay and immunohistochemistry were performed on tumors.

Results: Exendin-4 and metformin additively decreased the growth curve, but not the migration, of prostate cancer cells. The BrdU assay revealed that both Exendin-4 and metformin significantly decreased prostate cancer cell proliferation. Furthermore, metformin, but not Exendin-4, activated AMPK and induced apoptosis in LNCaP cells. The anti-proliferative effect of metformin was abolished by inhibition or knock down of AMPK. In vivo, Exendin-4 and metformin significantly decreased tumor size, and further significant tumor size reduction was observed after combined treatment. Immunohistochemistry on tumors revealed that the P504S and Ki67 expression decreased by Exendin-4 and/or metformin, and that metformin increased phospho-AMPK expression and the apoptotic cell number.

Conclusion: These data suggest that Exendin-4 and metformin attenuated prostate cancer growth by inhibiting proliferation, and that metformin inhibited proliferation by inducing apoptosis. Combined treatment with Exendin-4 and metformin attenuated prostate cancer growth more than separate treatments.

No MeSH data available.


Related in: MedlinePlus