Nature Cancer: Why the older you get, the more likely you are to develop cancer, mitochondrials are key, and mutations in aging-related mitochondrial genes lead to metabolic remodeling that accelerates intestinal tumors.

Metabolic changes are one of the key signs of tumor cells.
as early as 1956, Otto Warburg observed that tumor cells prioritized the use of glycolysis to produce ATP instead of mitochondrial oxidation phosphate (OXPHOS).
note that mitochondrials, as a special semi-autonomous cytogenetic device, have their own DNA and carry important functions within the cells as "energy factories".
, how does mitochondrials and tumors develop? Recently, researchers from the Wellcome Trust Mitochondrial Research Centre at the University of Newcastle in the United Kingdom published a research paper in the journal Nature Cancer entitled: Age-associated mitochondrial DNA mutations cause metabolic remodeling that contributes to accelerated intestinal tumorigenesis.
study showed that age-related mitochondrial DNA mutations caused defects in mitochondrial oxidation phosphate (OXPHOS) function, leading to changes in cell metabolism, which in turn accelerated the development of intestinal tumors.
, the scientists found that in tumor cells, the OXPHOS function of mitochondrials is reduced in many types of tumors.
, defects in the OXPHOS system are a common feature of many human aging tissues.
in many cancer types, colorectal cancer increases with age and is closely related to mitochondrial DNA (mtDNA) mutations.
the study, a team led by Laura C. Greaves looked at whether age-related mtDNA mutations played an important role in the development of colorectal cancer.
to test this, the researchers constructed a model of a mouse with colorectal cancer (Lgr5-creER; Apcfl/fl) with a defective OXPHOS system knocked out by the APC anti-cancer gene, and had mtDNA mutations.
the removal of the APC anti-cancer gene caused tumor cells to proliferate more rapidly and apoptosis to decrease, resulting in those mice with bigger tumors than the control group.
the APC knockout, OXPHOS system defects in mouse models of tumor growth faster immediately followed, the team also found that these colorectal cancer cells can be raised serine from the head synthesis pathway (SSP) metabolic remodeling to deal with OXPHOS system defects.
same time, the team conducted in-place immunologic tissue chemistry (IHC) analysis in human colorectal cancer samples and found that 18 of the 22 tumor samples with OXPHOS defects had one or more mtDNA mutations.
, they also observed similar mtDNA mutations in normally aging intestinal tissue samples.
The chemical analysis of THEXPHOS in-place immunological tissue for human colorectal cancer actually shows that there are multiple copies of the mitochondrial genome, but as we age, different copies of mitochondrial DNA (mtDNA) accumulate more and more mutations until the same soliotic cell mtDNA mutation accumulates to a high level within a single cell, which can eventually lead to defects in the OXPHOS system. Anna Smith, lead author of the
paper, says that single or a few mitochondrial DNA mutations do not have much impact, but when these mutations accumulate to a certain extent, they can lead to OXPHOS defects and metabolic changes, providing selective metabolic advantages in the oncology process, in addition, the mutation accumulation process is inextricable to age! Anna Smith also said their findings raise an important question - Is the incidence of colorectal cancer increasing in patients with mitochondrial disease caused by genetically pathogenic mtDNA mutations? In summary, the schematic of the hypothetical mechanisms of mtDNA mutations and OXPHOS defects that lead to tumor occurrence, the study confirmed in mouse models and in human clinical samples that mitochondrial DNA (mtDNA) mutates over time, leading to defects in mitochondrial oxyphosphation (OXPHOS) function, which alters the metabolism of cells and ultimately accelerates the development of colorectal cancer.
What's more, the study also found that age-related mitochondrial OXPHOS defects can promote the growth and survival of bowel cancer cells by increasing the serine synthesis pathway (SSP), which is an important target for tumor therapy interventions and could be developed in the future to effectively treat bowel tumors such as colorectal cancer.
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