Korean J Physiol Pharmacol.  2017 Mar;21(2):267-273. 10.4196/kjpp.2017.21.2.267.

The oncogenic effects of p53-inducible gene 3 (PIG3) in colon cancer cells

• Park SJ
• Kim HB
• Kim J
• Park S
• Kim SW
• Lee JH

• KMID: 2371046
• DOI: http://doi.org/10.4196/kjpp.2017.21.2.267

Abstract

The p53-inducible gene 3 (PIG3), initially identified as a gene downstream of p53, plays an important role in the apoptotic process triggered by p53-mediated reactive oxygen species (ROS) production. Recently, several studies have suggested that PIG3 may play a role in various types of cancer. However, the functional significance of PIG3 in cancer remains unclear. Here, we found that PIG3 was highly expressed in human colon cancer cell lines compared to normal colonderived fibroblasts. Therefore, we attempted to elucidate the functional role of PIG3 in colon cancer. PIG3 overexpression increases the colony formation, migration and invasion ability of HCT116 colon cancer cells. Conversely, these tumorigenic abilities were significantly decreased in in vitro studies with PIG3 knockdown HCT116 cells. PIG3 knockdown also attenuated the growth of mouse xenograft tumors. These results demonstrate that PIG3 is associated with the tumorigenic potential of cancer cells, both in vitro and in vivo, and could play a key oncogenic role in colon cancer.

Keyword

Cancer progression; Colon cancer; Oncogenesis; PIG3

MeSH Terms

Animals
Carcinogenesis
Cell Line
Colon*
Colonic Neoplasms*
Fibroblasts
Genes, vif
HCT116 Cells
Heterografts
Humans
In Vitro Techniques
Mice
Reactive Oxygen Species
Reactive Oxygen Species

Figure

• 

  Fig. 1 The expression levels of PIG3 in 6 colon cancer cell lines and normal colon-derived fibroblasts.PIG3 protein level was measured by Western bot analysis and quantified using Image J software. Data represent the mean±S.D. from triplicate experiments.

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  Fig. 2 PIG3 overexpression enhances the tumorigenicity of HCT116 cells in vitro.(A) Western blot analysis showed the increase of PIG3 expression in PIG3 overexpressing HCT 116 cells, compared to control vector expressing cells. a-tubulin was used as a loading control. (B) Control vector and PIG3 overexpressing cells were assessed for colony formation in soft agar for 14 days. (C) Cell migration and invasion assays were performed using the Transwell system. Data represent the mean cell numbers from 5 fields, ***p<0.001, compared to control.

• 

  Fig. 3 PIG3 knockdown by shRNA attenuates the tumorigenicity of HCT116 cells in vitro.(A) Cells stably expressing control shRNA and PIG3-specific shRNA were analyzed by Western blot using an anti-PIG3 antibody. a-tubulin was used as a loading control. (B) Colony formation assay performed on soft agar. (C) Cell migration and invasion assays were performed using the Transwell system. Data represent the average cell numbers from 5 fields. ***p<0.001, compared to control.

• 

  Fig. 4 Effects of PIG3 knockdown on tumor growth cells in a nude mice HCT116 xenograft model.Control-(white arrows) and PIG3 shRNA (yellow arrows) HCT116 cells were injected subcutaneously into the left and right flank of nude mice, respectively (n= 3). (A) Tumor volumes were measured every 4 days over a period of 40 days. (B) The morphology of nude mice (upper panel) and xenograft tumors (lower panel) were photographed 40 days after injection. (C) The graph represents the average of the tumor weights. Values are means of tumor weights±S.D. from triplicate experiments. ***p<0.001, compared to control shRNA-transfected group. (D) Tumor tissues were subjected to H&E staining and immunostaining for determination of expression of PIG3 in the tumor xenografts.

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