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Novel anti-tumor mechanism of galanin receptor type 2 in head and neck squamous cell carcinoma cells.

Uehara T, Kanazawa T, Mizukami H, Uchibori R, Tsukahara T, Urabe M, Kume A, Misawa K, Carey TE, Suzuki M, Ichimura K, Ozawa K - Cancer Sci. (2013)

Bottom Line: In this study, we first transduced HEp-2 and KB cell lines using a recombinant adeno-associated virus (rAAV)-green fluorescent protein (GFP) vector and confirmed a high GFP expression rate (>90%) in both cell lines at the standard vector dose.Additionally, the annexin V-positive rate and sub-G0/G1 phase population were significantly elevated in HEp-2 cells (mock vs GALR2: 12.3 vs 25.0% (P < 0.01) and 9.1 vs 32.0% (P < 0.05), respectively) after 48 h.Furthermore, in HEp-2 cells, GALR2-mediated apoptosis was caspase-independent, involving downregulation of ERK1/2, followed by induction of the pro-apoptotic Bcl-2 protein, Bim.

View Article: PubMed Central - PubMed

Affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, Graduate School of Medicine, University of the Ryukyus, Nishihara, Japan; Division of Genetic Therapeutics, Center for Molecular Medicine, Jichi Medical University, Shimotsuke, Japan; Department of Otolaryngology, Head and Neck Surgery, Jichi Medical University School of Medicine, Shimotsuke, Japan.

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Effect of the MEK inhibitor PD98059 on head and neck squamous cell carcinoma (HNSCC) cells. (a) Phosphorylation states of ERK1/2 after treatment with PD98059. (b) Effect of PD98059 on proliferation of HNSCC cells. (c) Apoptosis analysis by an Annexin V in HNSCC cells. *P < 0.05, **P < 0.01.
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fig06: Effect of the MEK inhibitor PD98059 on head and neck squamous cell carcinoma (HNSCC) cells. (a) Phosphorylation states of ERK1/2 after treatment with PD98059. (b) Effect of PD98059 on proliferation of HNSCC cells. (c) Apoptosis analysis by an Annexin V in HNSCC cells. *P < 0.05, **P < 0.01.

Mentions: To determine whether dephosphorylation of ERK1/2 results in cell growth inhibition and apoptosis induction in HNSCC cells, we examined the reproducibility of GALR2-mediated cytotoxicity using a specific ERK (MEK1) inhibitor, PD98059. As expected, dephosphorylation of ERK1/2 was induced by treatment of both HNSCC cell lines with PD98059 at 20–100 μM for 48 h (Fig.6a). When cells were cultured in SFM in the presence of PD98059 for 48 h, dose-dependent cell growth suppression (Fig.6b) and significant apoptosis induction (Fig.6c) were observed; these effects were more marked in HEp-2 cells. In addition, dose-dependent upregulation of Bim was observed in HEp-2, but not in KB cells, after incubation with PD98059 for 48 h (Fig.6a). Thus, the GALR2-mediated cytotoxic effects involved at least downregulation of ERK1/2, while Bim may play a role in modulation of GALR2-mediated apoptotic sensitivity. However, despite apoptosis induction in KB cells, Bim activation was not observed, suggesting the existence of multiple signaling pathways for apoptosis induction.


Novel anti-tumor mechanism of galanin receptor type 2 in head and neck squamous cell carcinoma cells.

Uehara T, Kanazawa T, Mizukami H, Uchibori R, Tsukahara T, Urabe M, Kume A, Misawa K, Carey TE, Suzuki M, Ichimura K, Ozawa K - Cancer Sci. (2013)

Effect of the MEK inhibitor PD98059 on head and neck squamous cell carcinoma (HNSCC) cells. (a) Phosphorylation states of ERK1/2 after treatment with PD98059. (b) Effect of PD98059 on proliferation of HNSCC cells. (c) Apoptosis analysis by an Annexin V in HNSCC cells. *P < 0.05, **P < 0.01.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4317884&req=5

fig06: Effect of the MEK inhibitor PD98059 on head and neck squamous cell carcinoma (HNSCC) cells. (a) Phosphorylation states of ERK1/2 after treatment with PD98059. (b) Effect of PD98059 on proliferation of HNSCC cells. (c) Apoptosis analysis by an Annexin V in HNSCC cells. *P < 0.05, **P < 0.01.
Mentions: To determine whether dephosphorylation of ERK1/2 results in cell growth inhibition and apoptosis induction in HNSCC cells, we examined the reproducibility of GALR2-mediated cytotoxicity using a specific ERK (MEK1) inhibitor, PD98059. As expected, dephosphorylation of ERK1/2 was induced by treatment of both HNSCC cell lines with PD98059 at 20–100 μM for 48 h (Fig.6a). When cells were cultured in SFM in the presence of PD98059 for 48 h, dose-dependent cell growth suppression (Fig.6b) and significant apoptosis induction (Fig.6c) were observed; these effects were more marked in HEp-2 cells. In addition, dose-dependent upregulation of Bim was observed in HEp-2, but not in KB cells, after incubation with PD98059 for 48 h (Fig.6a). Thus, the GALR2-mediated cytotoxic effects involved at least downregulation of ERK1/2, while Bim may play a role in modulation of GALR2-mediated apoptotic sensitivity. However, despite apoptosis induction in KB cells, Bim activation was not observed, suggesting the existence of multiple signaling pathways for apoptosis induction.

Bottom Line: In this study, we first transduced HEp-2 and KB cell lines using a recombinant adeno-associated virus (rAAV)-green fluorescent protein (GFP) vector and confirmed a high GFP expression rate (>90%) in both cell lines at the standard vector dose.Additionally, the annexin V-positive rate and sub-G0/G1 phase population were significantly elevated in HEp-2 cells (mock vs GALR2: 12.3 vs 25.0% (P < 0.01) and 9.1 vs 32.0% (P < 0.05), respectively) after 48 h.Furthermore, in HEp-2 cells, GALR2-mediated apoptosis was caspase-independent, involving downregulation of ERK1/2, followed by induction of the pro-apoptotic Bcl-2 protein, Bim.

View Article: PubMed Central - PubMed

Affiliation: Department of Otorhinolaryngology, Head and Neck Surgery, Graduate School of Medicine, University of the Ryukyus, Nishihara, Japan; Division of Genetic Therapeutics, Center for Molecular Medicine, Jichi Medical University, Shimotsuke, Japan; Department of Otolaryngology, Head and Neck Surgery, Jichi Medical University School of Medicine, Shimotsuke, Japan.

Show MeSH
Related in: MedlinePlus