Fig. 7: MGL deficiency leads to increased COX-2 levels in MEFs and mouse lung tissues as well as human lung cancer cells.
From: Monoglyceride lipase gene knockout in mice leads to increased incidence of lung adenocarcinoma
a Increased COX-2 levels in the lung tissues of MGL-deficient mice. As indicated, lung tissues of two groups of mice were analyzed. Lanes 1 and 6: tissues from MGL-proficient mice, lanes 2–5 and 7–10: tissues from MGL-deficient mice. Densitometric analyses were performed as described in the Materials and methods. The relative COX-2 levels in lung tissues of MGL+/+, MGL+/− and MGL−/− animals in each group of mice are written below the western blot image. Figure 7a and Fig. 5b share the same Ponceau S staining images because the same membranes were separately used for analyzing EGFR (Fig. 5b) and COX-2 (Fig. 7a). Ponceau S staining was done on the membranes immediately after protein transfer and images were taken; the membranes were then cut into two parts based on the molecular markers and separately probed with anti-EGFR and anti-COX-2 antibodies. b COX-2 induction in MGL-deficient MEFs. Each sample represents MEFs isolated from different mice embryos. Vinculin serves as a loading control. c Increased COX-2 mRNA levels in MGL-deficient MEFs demonstrated by qRT-PCR. mRNAs extracted from MGL-proficient and -deficient MEFs were reverse transcribed and subjected to quantitative PCR (qRT-PCR). The qRT-PCR data represent results collected from three-independent experiments performed in triplicate. *P-value <0.05. d Re-expression of MGL (pSRα-MGL expression vector) in MGL knockout (MGL−/−) MEFs suppresses COX-2 levels. e, f MGL knockdown (by three different MGL shRNAs, 1, 2 and 3) in A549 human lung cancer cells increases COX-2 protein (e) and mRNA (f) levels. The qRT-PCR data represent results collected from three-independent experiments performed in triplicate. *P-value <0.05. g Increased TNF-α levels in the lung tissues of MGL-deficient mice. NT non-tumorous lung tissues, T tumorous lung tissue. h Schematic illustration of the proposed model depicting MGL involvement in the regulation of EGFR/ERK and COX-2/TNF-α in normal and cancer cells as discussed in the text of Discussion section
