1
|
Mladenova DN, Dahlstrom JE, Tran PN, Benthani F, Bean EG, Ng I, Pangon L, Currey N, Kohonen-Corish MRJ. HIF1α deficiency reduces inflammation in a mouse model of proximal colon cancer. Dis Model Mech 2015; 8:1093-103. [PMID: 26183215 PMCID: PMC4582097 DOI: 10.1242/dmm.019000] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2014] [Accepted: 07/07/2015] [Indexed: 01/21/2023] Open
Abstract
Hypoxia-inducible factor 1α (HIF1α) is a transcription factor that regulates the adaptation of cells to hypoxic microenvironments, for example inside solid tumours. Stabilisation of HIF1α can also occur in normoxic conditions in inflamed tissue or as a result of inactivating mutations in negative regulators of HIF1α. Aberrant overexpression of HIF1α in many different cancers has led to intensive efforts to develop HIF1α-targeted therapies. However, the role of HIF1α is still poorly understood in chronic inflammation that predisposes the colon to carcinogenesis. We have previously reported that the transcription of HIF1α is upregulated and that the protein is stabilised in inflammatory lesions that are caused by the non-steroidal anti-inflammatory drug (NSAID) sulindac in the mouse proximal colon. Here, we exploited this side effect of long-term sulindac administration to analyse the role of HIF1α in colon inflammation using mice with a Villin-Cre-induced deletion of Hif1α exon 2 in the intestinal epithelium (Hif1αΔIEC). We also analysed the effect of sulindac sulfide on the aryl hydrocarbon receptor (AHR) pathway in vitro in colon cancer cells. Most sulindac-treated mice developed visible lesions, resembling the appearance of flat adenomas in the human colon, surrounded by macroscopically normal mucosa. Hif1αΔIEC mice still developed lesions but they were smaller than in the Hif1α-floxed siblings (Hif1αF/F). Microscopically, Hif1αΔIEC mice had significantly less severe colon inflammation than Hif1αF/F mice. Molecular analysis showed reduced MIF expression and increased E-cadherin mRNA expression in the colon of sulindac-treated Hif1αΔIEC mice. However, immunohistochemistry analysis revealed a defect of E-cadherin protein expression in sulindac-treated Hif1αΔIEC mice. Sulindac sulfide treatment in vitro upregulated Hif1α, c-JUN and IL8 expression through the AHR pathway. Taken together, HIF1α expression augments inflammation in the proximal colon of sulindac-treated mice, and AHR activation by sulindac might lead to the reduction of E-cadherin protein levels through the mitogen-activated protein kinase (MAPK) pathway. Summary: HIF1α deficiency reduces inflammation in the mouse proximal colon but is associated with defective E-cadherin expression in colon epithelial cells when mice lacking intestinal epithelium expression of Hif1α are challenged with sulindac.
Collapse
Affiliation(s)
- Dessislava N Mladenova
- Kinghorn Cancer Centre, Garvan Institute of Medical Research, Sydney, New South Wales, 2010, Australia
| | - Jane E Dahlstrom
- ACT Pathology, The Canberra Hospital and Australian National University Medical School, Canberra, Australian Capital Territory, 2605, Australia
| | - Phuong N Tran
- Kinghorn Cancer Centre, Garvan Institute of Medical Research, Sydney, New South Wales, 2010, Australia
| | - Fahad Benthani
- Kinghorn Cancer Centre, Garvan Institute of Medical Research, Sydney, New South Wales, 2010, Australia
| | - Elaine G Bean
- ACT Pathology, The Canberra Hospital and Australian National University Medical School, Canberra, Australian Capital Territory, 2605, Australia
| | - Irvin Ng
- Kinghorn Cancer Centre, Garvan Institute of Medical Research, Sydney, New South Wales, 2010, Australia
| | - Laurent Pangon
- Kinghorn Cancer Centre, Garvan Institute of Medical Research, Sydney, New South Wales, 2010, Australia
| | - Nicola Currey
- Kinghorn Cancer Centre, Garvan Institute of Medical Research, Sydney, New South Wales, 2010, Australia
| | - Maija R J Kohonen-Corish
- Kinghorn Cancer Centre, Garvan Institute of Medical Research, Sydney, New South Wales, 2010, Australia St Vincent's Clinical School, UNSW Medicine, UNSW Australia, Sydney, New South Wales, 2052, Australia School of Medicine, University of Western Sydney, Sydney, New South Wales, 2560, Australia
| |
Collapse
|
2
|
Pangon L, Sigglekow ND, Larance M, Al-Sohaily S, Mladenova DN, Selinger CI, Musgrove EA, Kohonen-Corish MRJ. The "Mutated in Colorectal Cancer" Protein Is a Novel Target of the UV-Induced DNA Damage Checkpoint. Genes Cancer 2011; 1:917-26. [PMID: 21779472 DOI: 10.1177/1947601910388937] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Accepted: 10/05/2010] [Indexed: 01/04/2023] Open
Abstract
MCC is a potential tumor suppressor gene, which is silenced by promoter hypermethylation in a subset of colorectal cancers. However, its functions have remained poorly understood. In the present study, we describe a novel function of MCC in the DNA damage response. Several novel phosphorylation sites were identified by mass spectrometry, including 2 highly conserved ATM/ATR consensus sites at serine 118 and serine 120. In addition, exposure to ultraviolet radiation (UV), but not phleomycin, caused PI3K-dependent phosphorylation of MCC and its nuclear localization. Re-expression of MCC in HCT15 colorectal cancer cells led to a G2/M arrest, and MCC knockdown impaired the induction of a G2/M arrest following UV radiation. Finally, mutation of S118/120 to alanine did not affect MCC nuclear shuttling following UV but did impair MCC G2/M checkpoint activity. Thus, these results suggest that MCC is a novel target of the DNA damage checkpoint and that MCC is required for the complete cell cycle arrest in the G2/M phase in response to UV.
Collapse
Affiliation(s)
- Laurent Pangon
- Cancer Research Program, Garvan Institute of Medical Research, Sydney, Australia
| | | | | | | | | | | | | | | |
Collapse
|
3
|
Selinger CI, Cooper WA, Al-Sohaily S, Mladenova DN, Pangon L, Kennedy CW, McCaughan BC, Kohonen-Corish MR. Loss of expression of the chromatin remodelling protein SATB1 in lung cancer is an independent prognostic marker. Pathology 2011. [DOI: 10.1016/s0031-3025(16)33278-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
|