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Physical Intimacy of Breast Cancer Cells with Mesenchymal Stem Cells Elicits Trastuzumab Resistance through Src Activation.

Daverey A, Drain AP, Kidambi S - Sci Rep (2015)

Bottom Line: The development of resistance to trastuzumab is a major obstacle for lasting effective treatment of patients with ErbB2-overexpressing tumors.To our knowledge, this is the first report that showed PTEN loss without the use of chemical inhibitors, matrix stiffness, or silencing RNAs.Our findings show that MSCs are potent mediators of resistance to trastuzumab and might reveal targets to enhance trastuzumab efficacy in patients.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, NE, 68588.

ABSTRACT
The development of resistance to trastuzumab is a major obstacle for lasting effective treatment of patients with ErbB2-overexpressing tumors. Here, we demonstrate that the physical contact of breast cancer cells with mesenchymal stem cells (MSCs) is a potential modulator of trastuzumab response by activation of nonreceptor tyrosine kinase c-Src and down regulation of phosphatase and tensin homolog (PTEN). Using an in vitro patterned breast cancer/MSC co-culture model, we find that the presence of MSCs results in Src activation that is missing in cancer cells monoculture, transwell co-culture, and cells treated with MSCs conditioned media. Interestingly, the co-culture model also results in PTEN loss and activation of PI3K/AKT pathway that has been demonstrated as fundamental proliferative and survival pathways in clinical settings. To our knowledge, this is the first report that showed PTEN loss without the use of chemical inhibitors, matrix stiffness, or silencing RNAs. In addition, breast cancer cells in co-culture with MSCs conferred trastuzumab resistance in vitro as observed in the lack of inhibition of proliferative and migrative properties of the cancer cells. Our findings show that MSCs are potent mediators of resistance to trastuzumab and might reveal targets to enhance trastuzumab efficacy in patients.

No MeSH data available.


Related in: MedlinePlus

MSCs induces Src activation in patterned co-culture and not in conditioned media.(a) Immunostaining of Src (FITC, green) and MSCs marker- CD166 (Cy3, red) in (i) patterned monoculture of breast cancer cells; (ii) Breast cancer cells exposed to MSCs-CM; (iii) patterned co-culture of breast cancer cells with MSCs; (iv) enlarged image of (iii). (b) Upper panel, immunobots show activation of Src in breast cancer cells sorted after co-culture with MSCs using FACS, and in breast cancer cells exposed to MSCs-CM and in transwell co-culture. Lower panel, quantification of band intensity to assess the relative phosphorylation of Src at tyrosine 416 position (Y416). Mean ± SD; n = 3 independent experiments; *p < 0.05 compared with monoculture; **p < 0.01 compared with monoculture.
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f3: MSCs induces Src activation in patterned co-culture and not in conditioned media.(a) Immunostaining of Src (FITC, green) and MSCs marker- CD166 (Cy3, red) in (i) patterned monoculture of breast cancer cells; (ii) Breast cancer cells exposed to MSCs-CM; (iii) patterned co-culture of breast cancer cells with MSCs; (iv) enlarged image of (iii). (b) Upper panel, immunobots show activation of Src in breast cancer cells sorted after co-culture with MSCs using FACS, and in breast cancer cells exposed to MSCs-CM and in transwell co-culture. Lower panel, quantification of band intensity to assess the relative phosphorylation of Src at tyrosine 416 position (Y416). Mean ± SD; n = 3 independent experiments; *p < 0.05 compared with monoculture; **p < 0.01 compared with monoculture.

Mentions: Given our observation that MSCs induce Src activation in random co-culture, we tested that phenomenon in our patterned co-culture system as well. To investigate this, we probed breast cancer cells and MSCs using antibodies against Src (red) and CD166 (green) (Fig. 3A). Akin to random co-culture, breast cancer cells in co-culture with MSCs indicated higher Src expression compared to monoculture and breast cancer cells exposed to conditioned media from MSCs (MSCs-CM) (Fig. 3A, upper panel). Quantification of fluorescence intensity shows that the Src expression in co-cultures increased ∼2 fold compared to the monoculture (Fig. 3A, lower panel). In co-culture, MSCs also show Src expression, however, merge images indicated that majority of the Src fluorescence is from the breast cancer cells.


Physical Intimacy of Breast Cancer Cells with Mesenchymal Stem Cells Elicits Trastuzumab Resistance through Src Activation.

Daverey A, Drain AP, Kidambi S - Sci Rep (2015)

MSCs induces Src activation in patterned co-culture and not in conditioned media.(a) Immunostaining of Src (FITC, green) and MSCs marker- CD166 (Cy3, red) in (i) patterned monoculture of breast cancer cells; (ii) Breast cancer cells exposed to MSCs-CM; (iii) patterned co-culture of breast cancer cells with MSCs; (iv) enlarged image of (iii). (b) Upper panel, immunobots show activation of Src in breast cancer cells sorted after co-culture with MSCs using FACS, and in breast cancer cells exposed to MSCs-CM and in transwell co-culture. Lower panel, quantification of band intensity to assess the relative phosphorylation of Src at tyrosine 416 position (Y416). Mean ± SD; n = 3 independent experiments; *p < 0.05 compared with monoculture; **p < 0.01 compared with monoculture.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4561910&req=5

f3: MSCs induces Src activation in patterned co-culture and not in conditioned media.(a) Immunostaining of Src (FITC, green) and MSCs marker- CD166 (Cy3, red) in (i) patterned monoculture of breast cancer cells; (ii) Breast cancer cells exposed to MSCs-CM; (iii) patterned co-culture of breast cancer cells with MSCs; (iv) enlarged image of (iii). (b) Upper panel, immunobots show activation of Src in breast cancer cells sorted after co-culture with MSCs using FACS, and in breast cancer cells exposed to MSCs-CM and in transwell co-culture. Lower panel, quantification of band intensity to assess the relative phosphorylation of Src at tyrosine 416 position (Y416). Mean ± SD; n = 3 independent experiments; *p < 0.05 compared with monoculture; **p < 0.01 compared with monoculture.
Mentions: Given our observation that MSCs induce Src activation in random co-culture, we tested that phenomenon in our patterned co-culture system as well. To investigate this, we probed breast cancer cells and MSCs using antibodies against Src (red) and CD166 (green) (Fig. 3A). Akin to random co-culture, breast cancer cells in co-culture with MSCs indicated higher Src expression compared to monoculture and breast cancer cells exposed to conditioned media from MSCs (MSCs-CM) (Fig. 3A, upper panel). Quantification of fluorescence intensity shows that the Src expression in co-cultures increased ∼2 fold compared to the monoculture (Fig. 3A, lower panel). In co-culture, MSCs also show Src expression, however, merge images indicated that majority of the Src fluorescence is from the breast cancer cells.

Bottom Line: The development of resistance to trastuzumab is a major obstacle for lasting effective treatment of patients with ErbB2-overexpressing tumors.To our knowledge, this is the first report that showed PTEN loss without the use of chemical inhibitors, matrix stiffness, or silencing RNAs.Our findings show that MSCs are potent mediators of resistance to trastuzumab and might reveal targets to enhance trastuzumab efficacy in patients.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemical and Biomolecular Engineering, University of Nebraska-Lincoln, NE, 68588.

ABSTRACT
The development of resistance to trastuzumab is a major obstacle for lasting effective treatment of patients with ErbB2-overexpressing tumors. Here, we demonstrate that the physical contact of breast cancer cells with mesenchymal stem cells (MSCs) is a potential modulator of trastuzumab response by activation of nonreceptor tyrosine kinase c-Src and down regulation of phosphatase and tensin homolog (PTEN). Using an in vitro patterned breast cancer/MSC co-culture model, we find that the presence of MSCs results in Src activation that is missing in cancer cells monoculture, transwell co-culture, and cells treated with MSCs conditioned media. Interestingly, the co-culture model also results in PTEN loss and activation of PI3K/AKT pathway that has been demonstrated as fundamental proliferative and survival pathways in clinical settings. To our knowledge, this is the first report that showed PTEN loss without the use of chemical inhibitors, matrix stiffness, or silencing RNAs. In addition, breast cancer cells in co-culture with MSCs conferred trastuzumab resistance in vitro as observed in the lack of inhibition of proliferative and migrative properties of the cancer cells. Our findings show that MSCs are potent mediators of resistance to trastuzumab and might reveal targets to enhance trastuzumab efficacy in patients.

No MeSH data available.


Related in: MedlinePlus