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miRs-134 and -370 function as tumor suppressors in colorectal cancer by independently suppressing EGFR and PI3K signalling.

El-Daly SM, Abba ML, Patil N, Allgayer H - Sci Rep (2016)

Bottom Line: Furthermore, overexpression of miR-134 or -370 resulted in a significant reduction of cell proliferation, colony formation, migration, invasion and in-vivo tumor growth and metastasis.Concurrent experiments with small interfering RNAs targeting the prime targets show that our selected miRNAs exert a greater functional influence and affect more downstream molecules than is seen with silencing of the individual proteins.Taken together, these data indicate that miRs-134 and -370 are potential tumour suppressor miRNAs and could play a fundamental role in suppressing colorectal cancer tumorigenesis through their ability to co-ordinately regulate EGFR signalling cascade by independently targeting EGFR and PIK3CA.

View Article: PubMed Central - PubMed

Affiliation: Department of Experimental Surgery, Medical Faculty Mannheim, University of Heidelberg, Germany.

ABSTRACT
Growth factor receptor signalling plays a central and critical role in colorectal cancer. Most importantly, the EGFR signalling cascade involving PI3K/AKT/mTOR and Raf/MEK/ERK pathways are particularly relevant, since they are commonly activated in several cancer entities, including colorectal cancer. In this study, we show that miRs-134 and -370 are both capable of regulating these pathways by targeting EGFR and PIK3CA. In three different colorectal cancer cell lines (DLD1, HCT-116 and RKO), suppression of EGFR and PIK3CA through the enhanced expression of miR-134 or -370 led to a suppression of the key molecules of the PI3K/AKT/mTOR pathway. Furthermore, overexpression of miR-134 or -370 resulted in a significant reduction of cell proliferation, colony formation, migration, invasion and in-vivo tumor growth and metastasis. Concurrent experiments with small interfering RNAs targeting the prime targets show that our selected miRNAs exert a greater functional influence and affect more downstream molecules than is seen with silencing of the individual proteins. Taken together, these data indicate that miRs-134 and -370 are potential tumour suppressor miRNAs and could play a fundamental role in suppressing colorectal cancer tumorigenesis through their ability to co-ordinately regulate EGFR signalling cascade by independently targeting EGFR and PIK3CA.

No MeSH data available.


Related in: MedlinePlus

miRs-134 and -370 suppress in vitro migration and invasion.(a–c) Boyden chamber migration and invasion assays in HCT116, RKO and DLD-1 colorectal cancer cell lines treated with miR-134 and miR-370 mimics, miR-134 and miR-370 inhibitors or siRNAs targeting EGFR and PIK3CA, respectively. 5 × 104 and 1 × 105 cells were seeded in transwell chambers for migration and invasion in serum deprived medium and the mobility of cells towards serum containing media was measured by the Cell Titer-Glo assay. Values represent the percentage of migrated cells in relation to the total number of cells.
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f4: miRs-134 and -370 suppress in vitro migration and invasion.(a–c) Boyden chamber migration and invasion assays in HCT116, RKO and DLD-1 colorectal cancer cell lines treated with miR-134 and miR-370 mimics, miR-134 and miR-370 inhibitors or siRNAs targeting EGFR and PIK3CA, respectively. 5 × 104 and 1 × 105 cells were seeded in transwell chambers for migration and invasion in serum deprived medium and the mobility of cells towards serum containing media was measured by the Cell Titer-Glo assay. Values represent the percentage of migrated cells in relation to the total number of cells.

Mentions: Although the PI3K pathway is primarily channeled to enhancing survival, proliferation and growth, a number of studies have also shown that this pathway also supports migration, invasion and metastasis via a number of downstream mediators including EIF5A216 and Integrin-linked kinase17. Along these lines, we initially investigated the impact of miR-134 and -370 on in vitro migration and invasion. Using the Boyden chamber assay, with and without the addition of a matrigel coating, for invasion and migration assays respectively, we were able to show that both miR-134 and miR-370 mimics could significantly suppress migration and invasion in RKO, HCT-116 and DLD-1 colorectal cancer cell lines. Consistently, treatment with the inhibitors of the two miRNAs yielded the opposite effect, where we observed enhanced invasion, especially in DLD-1 cells. Small interfering RNAs (siRNAs) targeting the key signaling molecules; PIK3CA and EGFR also caused a significant decrease in migration and invasion, but interestingly, not to the same extent as with the miRNA mimics (Fig. 4a–c).


miRs-134 and -370 function as tumor suppressors in colorectal cancer by independently suppressing EGFR and PI3K signalling.

El-Daly SM, Abba ML, Patil N, Allgayer H - Sci Rep (2016)

miRs-134 and -370 suppress in vitro migration and invasion.(a–c) Boyden chamber migration and invasion assays in HCT116, RKO and DLD-1 colorectal cancer cell lines treated with miR-134 and miR-370 mimics, miR-134 and miR-370 inhibitors or siRNAs targeting EGFR and PIK3CA, respectively. 5 × 104 and 1 × 105 cells were seeded in transwell chambers for migration and invasion in serum deprived medium and the mobility of cells towards serum containing media was measured by the Cell Titer-Glo assay. Values represent the percentage of migrated cells in relation to the total number of cells.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4837379&req=5

f4: miRs-134 and -370 suppress in vitro migration and invasion.(a–c) Boyden chamber migration and invasion assays in HCT116, RKO and DLD-1 colorectal cancer cell lines treated with miR-134 and miR-370 mimics, miR-134 and miR-370 inhibitors or siRNAs targeting EGFR and PIK3CA, respectively. 5 × 104 and 1 × 105 cells were seeded in transwell chambers for migration and invasion in serum deprived medium and the mobility of cells towards serum containing media was measured by the Cell Titer-Glo assay. Values represent the percentage of migrated cells in relation to the total number of cells.
Mentions: Although the PI3K pathway is primarily channeled to enhancing survival, proliferation and growth, a number of studies have also shown that this pathway also supports migration, invasion and metastasis via a number of downstream mediators including EIF5A216 and Integrin-linked kinase17. Along these lines, we initially investigated the impact of miR-134 and -370 on in vitro migration and invasion. Using the Boyden chamber assay, with and without the addition of a matrigel coating, for invasion and migration assays respectively, we were able to show that both miR-134 and miR-370 mimics could significantly suppress migration and invasion in RKO, HCT-116 and DLD-1 colorectal cancer cell lines. Consistently, treatment with the inhibitors of the two miRNAs yielded the opposite effect, where we observed enhanced invasion, especially in DLD-1 cells. Small interfering RNAs (siRNAs) targeting the key signaling molecules; PIK3CA and EGFR also caused a significant decrease in migration and invasion, but interestingly, not to the same extent as with the miRNA mimics (Fig. 4a–c).

Bottom Line: Furthermore, overexpression of miR-134 or -370 resulted in a significant reduction of cell proliferation, colony formation, migration, invasion and in-vivo tumor growth and metastasis.Concurrent experiments with small interfering RNAs targeting the prime targets show that our selected miRNAs exert a greater functional influence and affect more downstream molecules than is seen with silencing of the individual proteins.Taken together, these data indicate that miRs-134 and -370 are potential tumour suppressor miRNAs and could play a fundamental role in suppressing colorectal cancer tumorigenesis through their ability to co-ordinately regulate EGFR signalling cascade by independently targeting EGFR and PIK3CA.

View Article: PubMed Central - PubMed

Affiliation: Department of Experimental Surgery, Medical Faculty Mannheim, University of Heidelberg, Germany.

ABSTRACT
Growth factor receptor signalling plays a central and critical role in colorectal cancer. Most importantly, the EGFR signalling cascade involving PI3K/AKT/mTOR and Raf/MEK/ERK pathways are particularly relevant, since they are commonly activated in several cancer entities, including colorectal cancer. In this study, we show that miRs-134 and -370 are both capable of regulating these pathways by targeting EGFR and PIK3CA. In three different colorectal cancer cell lines (DLD1, HCT-116 and RKO), suppression of EGFR and PIK3CA through the enhanced expression of miR-134 or -370 led to a suppression of the key molecules of the PI3K/AKT/mTOR pathway. Furthermore, overexpression of miR-134 or -370 resulted in a significant reduction of cell proliferation, colony formation, migration, invasion and in-vivo tumor growth and metastasis. Concurrent experiments with small interfering RNAs targeting the prime targets show that our selected miRNAs exert a greater functional influence and affect more downstream molecules than is seen with silencing of the individual proteins. Taken together, these data indicate that miRs-134 and -370 are potential tumour suppressor miRNAs and could play a fundamental role in suppressing colorectal cancer tumorigenesis through their ability to co-ordinately regulate EGFR signalling cascade by independently targeting EGFR and PIK3CA.

No MeSH data available.


Related in: MedlinePlus