CORRESPONDENCE

RESPONSE: Multidrug-Resistant MCF-7 Cells: An Identity Crisis?

Farzaneh Pirnia, Markus M. Borner

Affiliation of authors: F. Pirnia, M. M. Borner, Institute of Medical Oncology, Inselspital, Bern, Switzerland.

Correspondence to: Markus M. Borner, M.D., University of Bern, Institute of Medical Oncology, Inselspital, CH-3010 Bern, Switzerland (e-mail: markus.borner{at}insel.ch).

We read with great interest the correspondence by Mehta et al. These authors propose the hypothesis that the various doxorubicin (ADR)-selected MCF-7 sublines may result from the selective expansion of inherently resistant subclones that contaminate the parental MCF-7 cell line and that harbor the full-length CASP-3 gene. Although this theory is quite interesting, we have some caveats (1). Because the CASP-3 gene is deleted in parental MCF-7 (1), it is difficult to understand how this genotype could have been reverted in the hypothetically inherently resistant subclones (2). In our original description, we assessed the nonidentity of MCF-7 and MCF-7 TH by DNA fingerprinting (2). This method is more reliable than phenotypic karyotyping (3). When they claim that an inherently resistant subclone contains functional caspase-3, Mehta et al. somehow contradict the finding that caspase-3 restores chemotherapy sensitivity in MCF-7 cells (3).

Most importantly, Mehta et al. explain their hypothesis with a contamination of the parental MCF-7 cell line. Thus, we strongly caution against retaining the original nomenclature—MCF-7/ADR or MCF-7 TH—for these sublines of unknown origin. Good research cannot be performed with tools of uncertain identity.

REFERENCES

1 Janicke RU, Sprengart ML, Wati MR, Porter AG. Caspase-3 is required for DNA fragmentation and morphological changes associated with apoptosis. J Biol Chem 1998;273:9357–60.[Abstract/Free Full Text]

2 Pirnia F, Breuleux M, Schneider E, Hochmeister M, Bates SE, Marti A, et al. Uncertain identity of doxorubicin-resistant MCF-7 cell lines expressing mutated p53. J Natl Cancer Inst 2000;92:1535–6.[Free Full Text]

3 Yang XH, Sladek TL, Liu X, Butler BR, Froelich CJ, Thor AD. Reconstitution of caspase-3 sensitizes MCF-7 breast cancer cells to doxorubicin- and etoposide-induced apoptosis. Cancer Res 2001;61:348–54.[Abstract/Free Full Text]



             
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