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Acidic extracellular pH promotes epithelial mesenchymal transition in Lewis lung carcinoma model.

Suzuki A, Maeda T, Baba Y, Shimamura K, Kato Y - Cancer Cell Int. (2014)

Bottom Line: Both variants showed decreased levels of E-cadherin and increased levels of vimentin at pH e 6.8.Acidic pH e also induced expression of mRNAs encoding the E-cadherin repressors, Zeb2, Twist1 and Twist2, as well as enhancing cell motility and in vitro invasion through Matrigel®.Acidic pH e can induce EMT in some types of carcinoma.

View Article: PubMed Central - PubMed

Affiliation: Department of Oral Function and Molecular Biology, Ohu University School of Dentistry, Koriyama, Japan ; Department of Oral Physiology and Biochemistry, Ohu University Graduate School of Dentistry, Koriyama, Japan.

ABSTRACT

Background: Epithelial mesenchymal transition (EMT) is thought to be an essential feature of malignant tumor cells when they spread into the stroma. Despite the extracellular acidity of tumor tissues, the effect of acidic extracellular pH (pH e ) on EMT in carcinoma models, including the Lewis lung carcinoma (LLC) model, remains unclear.

Methods: High and low metastatic LLC variants were generated by repeated tail vein injection of metastatic cells. DMEM/F12 medium, which has been supplemented with 15 mM HEPES, 4 mM phosphoric acid, and 1 g/L NaHCO3 and adjusted to the desire pH with HCl or NaOH, was used for cell culture. EMT marker gene expression was determined by quantitative reverse transcription-polymerase chain reaction. Migration and invasion activities were analyzed by wound healing assay and the Boyden chamber assay through Matrigel®, respectively.

Results: Low metastatic variant LLCm1 cells showed a cobble-stone like morphology at pH e 7.4. At pH e 6.8, however, their morphology became fibroblastic, similar in shape to high metastatic variant LLCm4 cells. Steady state levels of matrix metalloproteinase-9 (Mmp9) mRNA were induced by acidic pH e , maximizing at pH 6.8, with the levels of Mmp9 mRNA higher in LLCm4 than in LLCm1 cells. Both variants showed decreased levels of E-cadherin and increased levels of vimentin at pH e 6.8. Acidic pH e also induced expression of mRNAs encoding the E-cadherin repressors, Zeb2, Twist1 and Twist2, as well as enhancing cell motility and in vitro invasion through Matrigel®.

Conclusions: Acidic pH e can induce EMT in some types of carcinoma.

No MeSH data available.


Related in: MedlinePlus

Morphology and metastatic abilities of LLC variants. A. Photographs taken under an inverted phase contrast microscope of logarithmic phase cells grown in 10% FBS-containing medium. Bar, 100 μm. B. Cells were injected into the tail veins of syngeneic mice. Three weeks later, foci that had metastasized to the lungs were counted. Representative results were shown from two independent experiments. ***P<0.001.
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Fig1: Morphology and metastatic abilities of LLC variants. A. Photographs taken under an inverted phase contrast microscope of logarithmic phase cells grown in 10% FBS-containing medium. Bar, 100 μm. B. Cells were injected into the tail veins of syngeneic mice. Three weeks later, foci that had metastasized to the lungs were counted. Representative results were shown from two independent experiments. ***P<0.001.

Mentions: To compare the effect of acidic pHe on metastatic potential, we established two LLC variants (LLCm1 and LLCm4) by repeating cycles of the experimental pulmonary metastases. LLCm1 cells had a cobble-stone like morphology and were tightly attached to each other, whereas LLCm4 cells had a spindle shaped morphology and were scattered (Figure 1A). The metastatic potential of LLCm4 cells was 9 times higher than that of LLCm1 cells (Figure 1B).Figure 1


Acidic extracellular pH promotes epithelial mesenchymal transition in Lewis lung carcinoma model.

Suzuki A, Maeda T, Baba Y, Shimamura K, Kato Y - Cancer Cell Int. (2014)

Morphology and metastatic abilities of LLC variants. A. Photographs taken under an inverted phase contrast microscope of logarithmic phase cells grown in 10% FBS-containing medium. Bar, 100 μm. B. Cells were injected into the tail veins of syngeneic mice. Three weeks later, foci that had metastasized to the lungs were counted. Representative results were shown from two independent experiments. ***P<0.001.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4260188&req=5

Fig1: Morphology and metastatic abilities of LLC variants. A. Photographs taken under an inverted phase contrast microscope of logarithmic phase cells grown in 10% FBS-containing medium. Bar, 100 μm. B. Cells were injected into the tail veins of syngeneic mice. Three weeks later, foci that had metastasized to the lungs were counted. Representative results were shown from two independent experiments. ***P<0.001.
Mentions: To compare the effect of acidic pHe on metastatic potential, we established two LLC variants (LLCm1 and LLCm4) by repeating cycles of the experimental pulmonary metastases. LLCm1 cells had a cobble-stone like morphology and were tightly attached to each other, whereas LLCm4 cells had a spindle shaped morphology and were scattered (Figure 1A). The metastatic potential of LLCm4 cells was 9 times higher than that of LLCm1 cells (Figure 1B).Figure 1

Bottom Line: Both variants showed decreased levels of E-cadherin and increased levels of vimentin at pH e 6.8.Acidic pH e also induced expression of mRNAs encoding the E-cadherin repressors, Zeb2, Twist1 and Twist2, as well as enhancing cell motility and in vitro invasion through Matrigel®.Acidic pH e can induce EMT in some types of carcinoma.

View Article: PubMed Central - PubMed

Affiliation: Department of Oral Function and Molecular Biology, Ohu University School of Dentistry, Koriyama, Japan ; Department of Oral Physiology and Biochemistry, Ohu University Graduate School of Dentistry, Koriyama, Japan.

ABSTRACT

Background: Epithelial mesenchymal transition (EMT) is thought to be an essential feature of malignant tumor cells when they spread into the stroma. Despite the extracellular acidity of tumor tissues, the effect of acidic extracellular pH (pH e ) on EMT in carcinoma models, including the Lewis lung carcinoma (LLC) model, remains unclear.

Methods: High and low metastatic LLC variants were generated by repeated tail vein injection of metastatic cells. DMEM/F12 medium, which has been supplemented with 15 mM HEPES, 4 mM phosphoric acid, and 1 g/L NaHCO3 and adjusted to the desire pH with HCl or NaOH, was used for cell culture. EMT marker gene expression was determined by quantitative reverse transcription-polymerase chain reaction. Migration and invasion activities were analyzed by wound healing assay and the Boyden chamber assay through Matrigel®, respectively.

Results: Low metastatic variant LLCm1 cells showed a cobble-stone like morphology at pH e 7.4. At pH e 6.8, however, their morphology became fibroblastic, similar in shape to high metastatic variant LLCm4 cells. Steady state levels of matrix metalloproteinase-9 (Mmp9) mRNA were induced by acidic pH e , maximizing at pH 6.8, with the levels of Mmp9 mRNA higher in LLCm4 than in LLCm1 cells. Both variants showed decreased levels of E-cadherin and increased levels of vimentin at pH e 6.8. Acidic pH e also induced expression of mRNAs encoding the E-cadherin repressors, Zeb2, Twist1 and Twist2, as well as enhancing cell motility and in vitro invasion through Matrigel®.

Conclusions: Acidic pH e can induce EMT in some types of carcinoma.

No MeSH data available.


Related in: MedlinePlus