Giant polyploid cells are formed if DNA replication is uncoupled from mitosis . This process has been termed the endocycle and is a characteristic of p53-null cells , which is further increased by exposure to radiation . It was thought that the process of endocycles was irreversible and the resulting giant polyploid cells represent a reproductive dead end.
Polyploid tumor cells are created by cytotoxic and targeted therapies , therefore the frequency of tumor cells with elevated ploidy is likely to significantly increase during therapy. Further, many front-line therapies are genotoxic mutagens. In this scenario, the therapy itself imparts a mutator phenotype onto the tumor, with polyploidy functioning as a genetic buffer to reduce the effects of deleterious mutations, increasing the probability of beneficial mutations surviving within the polyploidy sub-population to drive disease recurrence.
Zhang S, Mercado-Uribe I, Liu J. Tumor stroma and differentiated cancer cells can be originated directly from polyploid giant cancer cells induced by paclitaxel. Int J Cancer (2013) 134:508–1810.1002/ijc.28319 [PMC free article.
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4033620/
Polyploidy represents a type of chromosomal instability (CIN), and CIN is a key for drug resistance. Please see following review for the concept:
Chromosomal instability (CIN): what it is and why it is crucial to cancer evolution.
Equally important, polyploid represents different system or "cellular species".
http://www.ncbi.nlm.nih.gov/pubmed/23605440
Hi Manu.
According to our results, increasing ROS resistance may be also accompanied
by increased average cell size and polyploidization, which seems to be key resistance
mechanism when connected with an escape from senescence.
See article:
https://www.researchgate.net/publication/286936596_Oxidative_Stress_Resistance_in_Metastatic_Prostate_Cancer_Renewal_by_Self-Eating
I hope this could help you.
Article Oxidative Stress Resistance in Metastatic Prostate Cancer: R...
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