The percentage of CD133+ cells in human colorectal cancer cell lines is influenced by Mycoplasma hyorhinis infection.
BACKGROUND
Mollicutes contamination is recognized to be a critical issue for the cultivation of continuous cell lines. In this work we characterized the effect of Mycoplasma hyorhinis contamination on CD133 expression in human colon cancer cell lines.


METHODS
MycoAlert and mycoplasma agar culture were used to detect mycoplasma contamination on GEO, SW480 and HT-29 cell lines. Restriction fragment length polymorphism assay was used to determine mycoplasma species. All cellular models were decontaminated by the use of a specific antibiotic panel (Enrofloxacin, Ciprofloxacin, BM Cyclin 1 and 2, Mycoplasma Removal Agent and MycoZap). The percentage of CD133 positive cells was analyzed by flow cytometry on GEO, SW480 and HT-29 cell lines, before and after Mycoplasma hyorhinis eradication.


RESULTS
Mycoplasma hyorhinis infected colon cancer cell lines showed an increased percentage of CD133+ cells as compared to the same cell lines rendered mycoplasma-free by effective exposure to antibiotic treatment. The percentage of CD133 positive cells increased again when mycoplasma negative cells were re-infected by Mycoplasma hyorhinis.


CONCLUSIONS
Mycoplasma hyorhinis infection has an important role on the quality of cultured human colon cancer cell lines giving a false positive increase of cancer stem cells fraction characterized by CD133 expression. Possible explanations are (i) the direct involvement of Mycoplasma on CD133 expression or (ii) the selective pressure on a subpopulation of cells characterized by constitutive CD133 expression.In keeping with United Kingdom Coordinating Committee on Cancer Research (UKCCCR) guidelines, the present data indicate the mandatory prerequisite, for investigators involved in human colon cancer research area, of employing mycoplasma-free cell lines in order to avoid the production of non-reproducible or even false data.
Mariotti
Elisabetta
E
CEINGE - Biotecnologie Avanzate, via Comunale Margherita 482, Napoli 80145, Italy.
Gemei
Marica
M
Mirabelli
Peppino
P
D'Alessio
Francesca
F
Di Noto
Rosa
R
Fortunato
Giuliana
G
Del Vecchio
Luigi
L
D000071916:AC133 Antigen; D015703:Antigens, CD / Q000096:biosynthesis*; D045744:Cell Line, Tumor; D015179:Colorectal Neoplasms / Q000276:immunology* / Q000382:microbiology*; D006023:Glycoproteins / Q000096:biosynthesis*; D019073:HT29 Cells; D006801:Humans; D009175:Mycoplasma Infections / Q000276:immunology*; D045790:Mycoplasma hyorhinis / Q000276:immunology*; D010455:Peptides; D008973:Tenericutes
D000071916:AC133 Antigen; D015703:Antigens, CD; D006023:Glycoproteins; C000606023:PROM1 protein, human; D010455:Peptides