Differential expressions and DNA methylation patterns of lysophosphatidic acid receptor genes in human colon cancer cells

Abstract

Lysophosphatidic acid (LPA), which is a bioactive phospholipid, interacts with specific G protein-coupled transmembrane receptors. Recently, alterations of LPA receptor genes have been reported in some tumor cells. In this study, we examined the expression profiles and DNA methylation status of LPA receptor 1-5 (LPA1-5) genes in human colon cancer cells and also looked for the mutations. Reverse transcription-polymerase chain reaction (PCR) and bisulfite sequencing analyses were carried out. While LPA1, LPA2, and LPA4 genes were expressed in DLD1, SW480, HCT116, CaCo-2, SW48, and LoVo cells, the expressions of LPA3 and LPA5 genes were various. These expression levels were correlated with DNA methylation status in the 5' upstream regions of the LPA receptor genes. Mutation analysis was also performed using a PCR-single-strand conformation polymorphism method. Although no mutations in LPA1, LPA3 and LPA5 genes were found in all types of cells, LPA2 mutations in DLD1 and SW48 cells, and LPA4 mutation were found in DLD1 cells. On the basis of the present results, we demonstrate that these colon cancer cells will be available to understanding the molecular pathway through LPA receptors in the development of tumor cells, and that LPA receptors may be new molecular targets for therapeutic approaches and chemoprevention.

<i>In vitro</i> effect of lysophosphatidic acid on proliferation, invasion and migration of human ovarian cancer cells

“…LPA has been shown to play a vital role in the invasion and migration of malignant tumor cells. The findings in this study further demonstrate that LPA administration is able to enhance the proliferation of ovarian cancer cells, which is consistent with previous investigations [10].…”

Different Expressions and DNA Methylation Patterns of Lysophosphatidic Acid Receptor Genes in Mouse Tumor Cells

“…Semi-quantitative RT-PCR analysis was performed as described previously [16,17] . Primer pairs used in this study were as follows: for mouse LPA1 (NCBI accession No.…”

“…In rodents, loss of LPA1 expression due to its aberrant DNA methylation was shown in rat tumor cells [17] . On the other hand, mutations of LPA receptor genes have also been detected in human and rodents tumors [16,18,19] . Therefore, it is suggested that alterations of LPA receptor genes may play important roles in the pathogenesis of tumor cells as well as LPA per se.…”

“…Our recent reports have indicated that distinct expression patterns of LPA receptor genes occur in human colon cancer cells [16] . In rodents, loss of LPA1 expression due to its aberrant DNA methylation was shown in rat tumor cells [17] .…”

LPAR2 (lysophosphatidic acid receptor 2)

“…The extra amino acids are the result of a guanine nucleotide deletion in the fourth to last codon (Contos and Chun, 2000). Additionally, in two human colon cancer cell lines, DLD1 and SW48, LPA2 and LPA4 were found to contain five mutations of G/C to A/T transitions (Tsujino et al, 2010). These mutated LPA2 receptors may alter LPA2 signaling through its respective G proteins and downstream pathways, and play a role in cancer progression.…”