Adipose triglyceride lipase promotes the proliferation of colorectal cancer cells via enhancing the lipolytic pathway

Figures

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  FIGURE 1. Elevated ATGL is associated with tumour progression in CRC. (A) ATGL IHC staining of 86 adjacent specimens and 94 CRC specimens in CRC Tissue Microarray (top, 100× magnification, Scale bar 200 μm; bottom, 400× magnification, Scale bar 50 μm). (B) Statistical analysis of ATGL staining of adjacent specimens versus CRC specimens. IHC was quantified by staining intensity (SI). H‐Score ≥5 was considered high ATGL expression; ***P < 0.001. (C) Representative images of ATGL IHC staining at different clinical stages (100× magnification). Scale bar 200 μm. (D) Statistical analysis of ATGL staining at different clinical stages; **P < 0.01 and ***P < 0.001 was compared with clinical stage I. (E) Overall survival of CRC patients in CRC Tissue Microarray with low and high ATGL expression

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  FIGURE 2. Detection of ATGL expression in CRC cell lines. (A, B) qRT‐PCR analysis (A) and Western blot analysis (B) of ATGL expression in CRC cell lines, and the CCD841 cells were used as normal control. (C, D) Overexpression efficiency of ATGL at mRNA level (C) and protein level (D) in SW480 and LoVo cell lines. (E, F) Knockdown efficiency of ATGL at mRNA level (E) and protein level (F) in HCT116 and SW620 cell lines. Data were represented as the mean ± SD of three independent experiments; *P < 0.05, **P < 0.01, ***P < 0.001

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  FIGURE 3. ATGL promotes CRC cell proliferation. (A) CCK‐8 detection for cell proliferation in SW480 and LoVo cells transduced with ATGL viruses and vector control. (B) CCK‐8 detection for cell proliferation in HCT116 and SW620 cells transfected with ATGL siRNA and siNC; **P < 0.01, ***P < 0.001. (C, D) Representative images of colony formation in indicated ATGL‐transduced, ATGL‐silenced or vector control cells. (E, F) EdU staining assay in indicated cells. Data were represented as the mean ± SD of three independent experiments

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  FIGURE 4. Knockdown of ATGL promotes apoptosis of CRC cells. (A) Detect apoptosis of indicated ATGL‐silenced and control cells by flow cytometry. (B) Representative images of TUNEL staining in HCT116 cells transduced with ATGL siRNA and siNC. All Bars represented the mean ± SD of three independent experiments; *P < 0.05, **P < 0.01

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  FIGURE 5. ATGL promotes the lipolytic pathway of CRC cells. (A) Detect the FFA content in indicated SW480 and HCT116 cells culture media after treatment with 400 μM OA for 6 hours; *P < 0.05. (B) Detect the TAG content in indicated SW480 and HCT116 cells after treatment with 400 μM OA for 6 hours; **P < 0.01, ***P < 0.001. (C) Representative images of lipid droplets in indicated SW480 and HCT116 cells after treatment with 400 μM OA for 6 hours and then stained with Oil Red O. (D) Quantification of lipid content are shown. All Bars represented the mean ± SD of three independent experiments; *P < 0.05, **P < 0.01. (E, F) GSEA in the TCGA CRC dataset showed that ATGL were positively correlated with sphingolipid metabolism (E) and CoA biosynthesis (F)

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  FIGURE 6. ATGL promotes the growth of CRC cells in vivo. (A‐C) The representative morphology (A), tumour growth rate (B) and tumour weight (C) were presented as a result of SW480‐Vector and SW480‐ATGL Xenograft Models; *P < 0.05, **P < 0.01. (D) Representative lipid droplets images in Xenograft Models tumours. (E) Statistical analysis of lipid droplets; *P < 0.05. (F) Representative Ki67 staining images in Xenograft Models tumours. (G) Statistical analysis of Ki67 staining. Data were expressed as mean ± SD; **P < 0.01