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Daily application of low magnitude mechanical stimulus inhibits the growth of MDA-MB-231 breast cancer cells in vitro.

Olcum M, Ozcivici E - Cancer Cell Int. (2014)

Bottom Line: Mechanical loads can regulate cell proliferation and differentiation at various stages of development and homeostasis.The signal was applied in oscillatory form at 90 Hz and 0.15 g, a regimen that would induce mechanical loads on MDA-MB-231 cells via inertial properties of cells rather than matrix deformations.Cell proliferation, viability, cycle, apoptosis, morphology and migration were tested via Trypan Blue dye exclusion, MTT, PI, Annexin V, Calcein-AM and phalloidin stains and scratch wound assays.

View Article: PubMed Central - PubMed

Affiliation: Program in Biotechnology and Bioengineering, Izmir Institute of Technology, Urla, Izmir Turkey.

ABSTRACT

Introduction: Mechanical loads can regulate cell proliferation and differentiation at various stages of development and homeostasis. However, the extension of this regulatory effect of mechanical loads on cancer cells is largely unknown. Increased physical compliance is one of the key features of cancer cells, which may hamper the transmission of mechanical loads to these cells within tumor microenvironment. Here we tested whether brief daily application of an external low magnitude mechanical stimulus (LMMS), would impede the growth of MDA-MB-231 aggressive type breast cancer cells in vitro for 3 wks of growth.

Methods: The signal was applied in oscillatory form at 90 Hz and 0.15 g, a regimen that would induce mechanical loads on MDA-MB-231 cells via inertial properties of cells rather than matrix deformations. Experimental cells were exposed to LMMS 15 min/day, 5 days/week in ambient conditions while control cells were sham loaded. Cell proliferation, viability, cycle, apoptosis, morphology and migration were tested via Trypan Blue dye exclusion, MTT, PI, Annexin V, Calcein-AM and phalloidin stains and scratch wound assays.

Results: Compared to sham controls, daily application of LMMS reduced the number and viability of cancerous MDA-MB-231 cells significantly after first week in the culture, while non-cancerous MCF10A cells were found to be unaffected. Flow cytomety analyses suggested that the observed decrease for the cancer cells in the LMMS group was due to a cell cycle arrest rather than apoptosis. LMMS further reduced cancer cell circularity and increased cytoskeletal actin in MDA-MB-231 cells.

Conclusion: Combined, results suggest that direct application of mechanical loads negatively regulate the proliferation of aggressive type cancer cells. If confirmed, this non-invasive approach may be integrated to the efforts for the prevention and/or treatment of cancer.

No MeSH data available.


Related in: MedlinePlus

MDA-MB-231 apoptosis/necrosis assessment with Annexin V – PI stains of control and LMMS groups for different experimental days. a) Representative gates applied for all samples determining dead, live and apoptotic cells. Fractions of b) dead cells (PI+), c) live cells (No stain) and d) apoptotic cells (Annexin V+, PI-) (*: p < 0.05 between LMMS and controls).
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Fig3: MDA-MB-231 apoptosis/necrosis assessment with Annexin V – PI stains of control and LMMS groups for different experimental days. a) Representative gates applied for all samples determining dead, live and apoptotic cells. Fractions of b) dead cells (PI+), c) live cells (No stain) and d) apoptotic cells (Annexin V+, PI-) (*: p < 0.05 between LMMS and controls).

Mentions: Control and LMMS cells were stained with Annexin V – PI documented for the apoptotic status of experimental cells (Figure 3a). No difference (all p > 0.15) in the fraction of apoptotic cells were observed between control and LMMS groups (Figure 3d). Fraction of dead cells in LMMS group was 51% (p < 0.01) and 28% (p = 0.05) larger at D12 and D19 compared to controls (Figure 3b). At D12, fraction of live cells had small but a significant reduction (1.1%, p < 0.01) compared to control cells (Figure 3c). Furthermore, fraction of live cells at D12 showed a similar reduction (3%, p = 0.02) as determined by Calcein-AM staining (Table 2).Figure 3


Daily application of low magnitude mechanical stimulus inhibits the growth of MDA-MB-231 breast cancer cells in vitro.

Olcum M, Ozcivici E - Cancer Cell Int. (2014)

MDA-MB-231 apoptosis/necrosis assessment with Annexin V – PI stains of control and LMMS groups for different experimental days. a) Representative gates applied for all samples determining dead, live and apoptotic cells. Fractions of b) dead cells (PI+), c) live cells (No stain) and d) apoptotic cells (Annexin V+, PI-) (*: p < 0.05 between LMMS and controls).
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4209025&req=5

Fig3: MDA-MB-231 apoptosis/necrosis assessment with Annexin V – PI stains of control and LMMS groups for different experimental days. a) Representative gates applied for all samples determining dead, live and apoptotic cells. Fractions of b) dead cells (PI+), c) live cells (No stain) and d) apoptotic cells (Annexin V+, PI-) (*: p < 0.05 between LMMS and controls).
Mentions: Control and LMMS cells were stained with Annexin V – PI documented for the apoptotic status of experimental cells (Figure 3a). No difference (all p > 0.15) in the fraction of apoptotic cells were observed between control and LMMS groups (Figure 3d). Fraction of dead cells in LMMS group was 51% (p < 0.01) and 28% (p = 0.05) larger at D12 and D19 compared to controls (Figure 3b). At D12, fraction of live cells had small but a significant reduction (1.1%, p < 0.01) compared to control cells (Figure 3c). Furthermore, fraction of live cells at D12 showed a similar reduction (3%, p = 0.02) as determined by Calcein-AM staining (Table 2).Figure 3

Bottom Line: Mechanical loads can regulate cell proliferation and differentiation at various stages of development and homeostasis.The signal was applied in oscillatory form at 90 Hz and 0.15 g, a regimen that would induce mechanical loads on MDA-MB-231 cells via inertial properties of cells rather than matrix deformations.Cell proliferation, viability, cycle, apoptosis, morphology and migration were tested via Trypan Blue dye exclusion, MTT, PI, Annexin V, Calcein-AM and phalloidin stains and scratch wound assays.

View Article: PubMed Central - PubMed

Affiliation: Program in Biotechnology and Bioengineering, Izmir Institute of Technology, Urla, Izmir Turkey.

ABSTRACT

Introduction: Mechanical loads can regulate cell proliferation and differentiation at various stages of development and homeostasis. However, the extension of this regulatory effect of mechanical loads on cancer cells is largely unknown. Increased physical compliance is one of the key features of cancer cells, which may hamper the transmission of mechanical loads to these cells within tumor microenvironment. Here we tested whether brief daily application of an external low magnitude mechanical stimulus (LMMS), would impede the growth of MDA-MB-231 aggressive type breast cancer cells in vitro for 3 wks of growth.

Methods: The signal was applied in oscillatory form at 90 Hz and 0.15 g, a regimen that would induce mechanical loads on MDA-MB-231 cells via inertial properties of cells rather than matrix deformations. Experimental cells were exposed to LMMS 15 min/day, 5 days/week in ambient conditions while control cells were sham loaded. Cell proliferation, viability, cycle, apoptosis, morphology and migration were tested via Trypan Blue dye exclusion, MTT, PI, Annexin V, Calcein-AM and phalloidin stains and scratch wound assays.

Results: Compared to sham controls, daily application of LMMS reduced the number and viability of cancerous MDA-MB-231 cells significantly after first week in the culture, while non-cancerous MCF10A cells were found to be unaffected. Flow cytomety analyses suggested that the observed decrease for the cancer cells in the LMMS group was due to a cell cycle arrest rather than apoptosis. LMMS further reduced cancer cell circularity and increased cytoskeletal actin in MDA-MB-231 cells.

Conclusion: Combined, results suggest that direct application of mechanical loads negatively regulate the proliferation of aggressive type cancer cells. If confirmed, this non-invasive approach may be integrated to the efforts for the prevention and/or treatment of cancer.

No MeSH data available.


Related in: MedlinePlus