Abstract 49: Differences in glutamine dependence among breast cancer cell lines

Metabolism plays a key role in cell survival and “adaptation” in cancer cells, thus influencing therapeutic resistance and metastasis. As an indication of robust connections between metabolism and cancer, the oncogenic activity of the Myc protein depends on its effects on glucose and glutamine metabolism. We tested the hypothesis that glutamine-dependence for growth in cell culture medium would correlate with metastatic ability of breast cancer cell lines. We chose a variety of cell lines spanning a spectrum from normal to most aggressive: 1) MCF10A immortalized normal breast epithelial cell line, 2) MCF10A/COX-2, a COX-2 transfected premalignant breast cancer cell line, 3) MCF7, a luminal origin estrogen receptor-positive weakly-tumorigenic cell line, 4) MCF7/COX-2, a COX-2 transfected cell line, 5) MDA-MB-231-Luc, a basal origin highly tumorigenic cell line, 6) MDA-MB-231-BSC60, a cell line we established from a bone metastasis after two rounds of selection in female nude mice, 7) SUM149 inflammatory breast cancer (IBC) cell line, and 8) SUM149-FP76, a cell line we established from a fat pad tumor after one round of subcutaneous tumor growth and subsequent culture and inoculation into inguinal fat pad. We determined the long-term growth and survival of cell lines in culture medium without glutamine. Growth of MCF10A, MCF10A/COX-2, MCF7, and MCF7/COX-2 cell lines was not significantly inhibited upon glutamine deprivation; there was an initial modest inhibition (∼50% at day 4), but these cell lines later grew to confluency in culture dishes. In contrast, the metastatic cell lines MDA-MB-231-Luc, MDA-MB-231-BSC60, and SUM149 were severely growth inhibited (∼99% at day 30). Interestingly, although the SUM149-FP76 cell line was severely inhibited (95% at day 5) upon glutamine deprivation, some cells survived and grew to produce small cell colonies within two-weeks. On the other hand, the parental cell line SUM149 largely remained single-celled during the first two-weeks, and only yielded colonies after a much longer time period (2 months). A highly aggressive IBC cell line SUM190 behaved similar to the FP76 variant. We are currently investigating alterations in metabolic networks by whole-genome mRNA and microRNA analysis. In conclusion, 1) there are significant differences in glutamine-dependence between normal, premalignant, poorly metastatic, and metastatic breast cancer cell lines as only the metastatic cell lines exhibit severe dependence on glutamine, and 2) SUM149-FP76, selected to grow as a tumor in nude mice, was able to survive and produce slow-growing small colonies in glutamine-free medium much earlier than the parental SUM149 cell line. This result indicates that growing IBC tumors may involve selection of elastic variant cancer cells containing altered metabolic networks such that they can adjust to glutamine availability. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 49.