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Downregulation of miR203 induces overexpression of PIK3CA and predicts poor prognosis of gastric cancer patients.

Liang M, Shi B, Liu J, He L, Yi G, Zhou L, Yu G, Zhou X - Drug Des Devel Ther (2015)

Bottom Line: We observed that PIK3CA was significantly upregulated in gastric cancer tissues.In addition, our study indicated that miR203 inhibits cell proliferation and invasion via directly targeting and suppressing the PIK3CA expression.Our further study also reported that overexpression of miR203 inhibited phosphorylation of AKT, while cotransfection of PIK3CA reversed the effect of miR203.

View Article: PubMed Central - PubMed

Affiliation: Department of Oncology, The fifth affiliated hospital of Guangzhou Medical University, Guangzhou, Guangdong, People's Republic of China.

ABSTRACT

Background: Despite advances in clinical therapies and technologies, the prognosis for patients with gastric cancer is still poor. The aim of this study is to investigate new predictive markers for prognosis of gastric cancer.

Methods: In this study, we evaluated the expression pattern of PIK3CA in 107 gastric cancer specimens and their adjacent nontumorous tissues. PIK3CA siRNA was synthesized and transfected into gastric cancer cell lines. Colony formation and MTT assays were employed to analyze the cell proliferation. PIK3CA expression was examined by using immunohistochemical analysis and Western blot assay. Transwell invasion assay was used to detect the invasion capability of the cells. Luciferase activity was examined by using 3'-untranslated region luciferase reporter assays.

Results: We observed that PIK3CA was significantly upregulated in gastric cancer tissues. High expression level of PIK3CA was detectable in 48 (44.86%) of the gastric cancer specimens, and correlated with poor prognosis. In addition, our study indicated that miR203 inhibits cell proliferation and invasion via directly targeting and suppressing the PIK3CA expression. MiR203 expression is downregulated in gastric cancer tissues. Moreover, low expression level of miR203 predicted poor prognosis of gastric patients and induced overexpression of PIK3CA. Our further study also reported that overexpression of miR203 inhibited phosphorylation of AKT, while cotransfection of PIK3CA reversed the effect of miR203.

Conclusion: Our study suggested a miR203-PIK3CA-AKT signaling pathway in gastric cancer cells. This signaling pathway might play an important role in gastric cancer genesis and development.

No MeSH data available.


Related in: MedlinePlus

MiR203 expression level correlated with the expression of PIK3CA, and significantly decreased gastric cancer cell proliferation and invasion.Notes: (A) Luciferase reporter gene assay indicated that miR203 targeted PIK3CA. (B) The miR203 expression pattern in gastric cancer cells. (C) The PIK3CA expression pattern in gastric cancer cells. (D) Overexpression of miR203 in HGC-27 decreased PIK3CA expression and knockdown of miR203 in SGC-7901 increased PIK3CA expression, this result indicated that miR203 expression negatively correlated with PIK3CA. (E) Overexpression of PIK3CA in SGC-7901 and knockdown of PIK3CA in HGC-27. (F) MTT assay suggested that miR203 mimics inhibited proliferation of gastric cancer cells partly due to downregulating PIK3CA expression. (G) MTT assay suggested that miR203 ASO increase proliferation of gastric cancer cells via upregulating PIK3CA. (H) Clone formation assays suggested that miR203 inhibited clone formation capacity by downregulating PIK3CA. (I) Transwell assays indicated that miR203 decreased invasion of gastric cancer cells by targeting PIK3CA. *P<0.05 represents the values compared to the NC group.Abbreviations: UTR, untranslated region; NC, normal control; ASO, antisense oligonucleotides; OD, optical density.
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f2-dddt-9-3607: MiR203 expression level correlated with the expression of PIK3CA, and significantly decreased gastric cancer cell proliferation and invasion.Notes: (A) Luciferase reporter gene assay indicated that miR203 targeted PIK3CA. (B) The miR203 expression pattern in gastric cancer cells. (C) The PIK3CA expression pattern in gastric cancer cells. (D) Overexpression of miR203 in HGC-27 decreased PIK3CA expression and knockdown of miR203 in SGC-7901 increased PIK3CA expression, this result indicated that miR203 expression negatively correlated with PIK3CA. (E) Overexpression of PIK3CA in SGC-7901 and knockdown of PIK3CA in HGC-27. (F) MTT assay suggested that miR203 mimics inhibited proliferation of gastric cancer cells partly due to downregulating PIK3CA expression. (G) MTT assay suggested that miR203 ASO increase proliferation of gastric cancer cells via upregulating PIK3CA. (H) Clone formation assays suggested that miR203 inhibited clone formation capacity by downregulating PIK3CA. (I) Transwell assays indicated that miR203 decreased invasion of gastric cancer cells by targeting PIK3CA. *P<0.05 represents the values compared to the NC group.Abbreviations: UTR, untranslated region; NC, normal control; ASO, antisense oligonucleotides; OD, optical density.

Mentions: Overexpression of PIK3CA indicated poor prognosis of gastric cancer patients; however, the mechanism of aberrant PIK3CA expression in gastric cancer is still unclear. By performing bioinformatics analysis, we supposed that PIK3CA is a potential target of miR203 (Figure 2A, up panel). To verify this correlation, we performed luciferase assays and found that miR203 could inhibit luciferase activity of PIK3CA 3′UTR-Luc vector transfected group but not PIK3CA 3′UTR-mutated-Luc vector group (Figure 2A, down panel). Then we tested expression levels of miR203 and PIK3CA in four gastric cancer cells. The results illustrated that there was a negative trend of PIK3CA expression in cells showing high expression of miR203 (Figure 2B and C). Moreover, the transfection of miR203 mimics and miR203 ASO indicated that miR203 mimics could decrease PIK3CA expression in PIK3CA high-expression gastric cell line, HGC-27. However, miR203 ASO could increase PIK3CA expression in SGC-7901, a miR203 high-expression but PIK3CA low-expression cell line (Figure 2D).


Downregulation of miR203 induces overexpression of PIK3CA and predicts poor prognosis of gastric cancer patients.

Liang M, Shi B, Liu J, He L, Yi G, Zhou L, Yu G, Zhou X - Drug Des Devel Ther (2015)

MiR203 expression level correlated with the expression of PIK3CA, and significantly decreased gastric cancer cell proliferation and invasion.Notes: (A) Luciferase reporter gene assay indicated that miR203 targeted PIK3CA. (B) The miR203 expression pattern in gastric cancer cells. (C) The PIK3CA expression pattern in gastric cancer cells. (D) Overexpression of miR203 in HGC-27 decreased PIK3CA expression and knockdown of miR203 in SGC-7901 increased PIK3CA expression, this result indicated that miR203 expression negatively correlated with PIK3CA. (E) Overexpression of PIK3CA in SGC-7901 and knockdown of PIK3CA in HGC-27. (F) MTT assay suggested that miR203 mimics inhibited proliferation of gastric cancer cells partly due to downregulating PIK3CA expression. (G) MTT assay suggested that miR203 ASO increase proliferation of gastric cancer cells via upregulating PIK3CA. (H) Clone formation assays suggested that miR203 inhibited clone formation capacity by downregulating PIK3CA. (I) Transwell assays indicated that miR203 decreased invasion of gastric cancer cells by targeting PIK3CA. *P<0.05 represents the values compared to the NC group.Abbreviations: UTR, untranslated region; NC, normal control; ASO, antisense oligonucleotides; OD, optical density.
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f2-dddt-9-3607: MiR203 expression level correlated with the expression of PIK3CA, and significantly decreased gastric cancer cell proliferation and invasion.Notes: (A) Luciferase reporter gene assay indicated that miR203 targeted PIK3CA. (B) The miR203 expression pattern in gastric cancer cells. (C) The PIK3CA expression pattern in gastric cancer cells. (D) Overexpression of miR203 in HGC-27 decreased PIK3CA expression and knockdown of miR203 in SGC-7901 increased PIK3CA expression, this result indicated that miR203 expression negatively correlated with PIK3CA. (E) Overexpression of PIK3CA in SGC-7901 and knockdown of PIK3CA in HGC-27. (F) MTT assay suggested that miR203 mimics inhibited proliferation of gastric cancer cells partly due to downregulating PIK3CA expression. (G) MTT assay suggested that miR203 ASO increase proliferation of gastric cancer cells via upregulating PIK3CA. (H) Clone formation assays suggested that miR203 inhibited clone formation capacity by downregulating PIK3CA. (I) Transwell assays indicated that miR203 decreased invasion of gastric cancer cells by targeting PIK3CA. *P<0.05 represents the values compared to the NC group.Abbreviations: UTR, untranslated region; NC, normal control; ASO, antisense oligonucleotides; OD, optical density.
Mentions: Overexpression of PIK3CA indicated poor prognosis of gastric cancer patients; however, the mechanism of aberrant PIK3CA expression in gastric cancer is still unclear. By performing bioinformatics analysis, we supposed that PIK3CA is a potential target of miR203 (Figure 2A, up panel). To verify this correlation, we performed luciferase assays and found that miR203 could inhibit luciferase activity of PIK3CA 3′UTR-Luc vector transfected group but not PIK3CA 3′UTR-mutated-Luc vector group (Figure 2A, down panel). Then we tested expression levels of miR203 and PIK3CA in four gastric cancer cells. The results illustrated that there was a negative trend of PIK3CA expression in cells showing high expression of miR203 (Figure 2B and C). Moreover, the transfection of miR203 mimics and miR203 ASO indicated that miR203 mimics could decrease PIK3CA expression in PIK3CA high-expression gastric cell line, HGC-27. However, miR203 ASO could increase PIK3CA expression in SGC-7901, a miR203 high-expression but PIK3CA low-expression cell line (Figure 2D).

Bottom Line: We observed that PIK3CA was significantly upregulated in gastric cancer tissues.In addition, our study indicated that miR203 inhibits cell proliferation and invasion via directly targeting and suppressing the PIK3CA expression.Our further study also reported that overexpression of miR203 inhibited phosphorylation of AKT, while cotransfection of PIK3CA reversed the effect of miR203.

View Article: PubMed Central - PubMed

Affiliation: Department of Oncology, The fifth affiliated hospital of Guangzhou Medical University, Guangzhou, Guangdong, People's Republic of China.

ABSTRACT

Background: Despite advances in clinical therapies and technologies, the prognosis for patients with gastric cancer is still poor. The aim of this study is to investigate new predictive markers for prognosis of gastric cancer.

Methods: In this study, we evaluated the expression pattern of PIK3CA in 107 gastric cancer specimens and their adjacent nontumorous tissues. PIK3CA siRNA was synthesized and transfected into gastric cancer cell lines. Colony formation and MTT assays were employed to analyze the cell proliferation. PIK3CA expression was examined by using immunohistochemical analysis and Western blot assay. Transwell invasion assay was used to detect the invasion capability of the cells. Luciferase activity was examined by using 3'-untranslated region luciferase reporter assays.

Results: We observed that PIK3CA was significantly upregulated in gastric cancer tissues. High expression level of PIK3CA was detectable in 48 (44.86%) of the gastric cancer specimens, and correlated with poor prognosis. In addition, our study indicated that miR203 inhibits cell proliferation and invasion via directly targeting and suppressing the PIK3CA expression. MiR203 expression is downregulated in gastric cancer tissues. Moreover, low expression level of miR203 predicted poor prognosis of gastric patients and induced overexpression of PIK3CA. Our further study also reported that overexpression of miR203 inhibited phosphorylation of AKT, while cotransfection of PIK3CA reversed the effect of miR203.

Conclusion: Our study suggested a miR203-PIK3CA-AKT signaling pathway in gastric cancer cells. This signaling pathway might play an important role in gastric cancer genesis and development.

No MeSH data available.


Related in: MedlinePlus