DNA repair is indispensable for survival after acute inflammation.
More than 15% of cancer deaths worldwide are associated with underlying infections or inflammatory conditions, therefore understanding how inflammation contributes to cancer etiology is important for both cancer prevention and treatment. Inflamed tissues are known to harbor elevated etheno-base (ε-base) DNA lesions induced by the lipid peroxidation that is stimulated by reactive oxygen and nitrogen species (RONS) released from activated neutrophils and macrophages. Inflammation contributes to carcinogenesis in part via RONS-induced cytotoxic and mutagenic DNA lesions, including ε-base lesions. The mouse alkyl adenine DNA glycosylase (AAG, also known as MPG) recognizes such base lesions, thus protecting against inflammation-associated colon cancer. Two other DNA repair enzymes are known to repair ε-base lesions, namely ALKBH2 and ALKBH3; thus, we sought to determine whether these DNA dioxygenase enzymes could protect against chronic inflammation-mediated colon carcinogenesis. Using established chemically induced colitis and colon cancer models in mice, we show here that ALKBH2 and ALKBH3 provide cancer protection similar to that of the DNA glycosylase AAG. Moreover, Alkbh2 and Alkbh3 each display apparent epistasis with Aag. Surprisingly, deficiency in all 3 DNA repair enzymes confers a massively synergistic phenotype, such that animals lacking all 3 DNA repair enzymes cannot survive even a single bout of chemically induced colitis.
Department of Biological Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA
Jennifer A
JA
Calvo
Lisiane B
LB
Meira
Chun-Yue I
CY
Lee
Catherine A
CA
Moroski-Erkul
Nona
N
Abolhassani
Koli
K
Taghizadeh
Lindsey W
LW
Eichinger
Sureshkumar
S
Muthupalani
Line M
LM
Nordstrand
Arne
A
Klungland
Leona D
LD
Samson
D000071499:AlkB Homolog 2, Alpha-Ketoglutarate-Dependent Dioxygenase; D000071500:AlkB Homolog 3, Alpha-Ketoglutarate-Dependent Dioxygenase; D000818:Animals; D001397:Azoxymethane / Q000494:pharmacology; D002273:Carcinogens / Q000494:pharmacology; D003092:Colitis / Q000139:chemically induced / Q000235:genetics* / Q000378:metabolism; D003106:Colon / Q000276:immunology / Q000473:pathology; D015179:Colorectal Neoplasms / Q000139:chemically induced / Q000235:genetics / Q000378:metabolism; D045647:DNA Glycosylases / Q000235:genetics* / Q000378:metabolism; D004260:DNA Repair; D045643:DNA Repair Enzymes / Q000235:genetics* / Q000378:metabolism; D016264:Dextran Sulfate / Q000494:pharmacology; D049308:Dioxygenases / Q000235:genetics* / Q000378:metabolism; D004843:Epistasis, Genetic; D005260:Female; D020022:Genetic Predisposition to Disease; D053208:Kaplan-Meier Estimate; D007928:Lethal Dose 50; D008070:Lipopolysaccharides / Q000494:pharmacology; D008297:Male; D051379:Mice; D057507:Mice, 129 Strain; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D010179:Pancreas / Q000276:immunology / Q000473:pathology; D010195:Pancreatitis / Q000139:chemically induced / Q000235:genetics* / Q000378:metabolism
D002273:Carcinogens; D008070:Lipopolysaccharides; D016264:Dextran Sulfate; D049308:Dioxygenases; D000071500:AlkB Homolog 3, Alpha-Ketoglutarate-Dependent Dioxygenase; C511887:Alkbh3 protein, mouse; D000071499:AlkB Homolog 2, Alpha-Ketoglutarate-Dependent Dioxygenase; C511886:Alkbh2 protein, mouse; C021565:3-methyladenine-DNA glycosylase; D045647:DNA Glycosylases; D045643:DNA Repair Enzymes; D001397:Azoxymethane