Selective Inhibition of A549 Lung Cancer Stem Cell Tumorspheres by a Bacterial Antibiotic Supernatant

Shirokawa, Jill M.; Girard, Anne-Lise; Patel, Yatra; Maiorano, John N.

Non-small cell lung cancer is one of the most prevalent types of cancer that is responsible for
the majority of cancer-related deaths worldwide. Recurrence and metastasis continue as a
major barriers to the successful treatment of non-small cell lung cancer. Cancer stem cells are a
main contributor to cancer recurrence and metastasis thus, a target for lung anticancer therapy.
Evidence that some antibiotics are effective cancer stem cell inhibitors makes the identification
of new antibiotic cancer stem cell inhibitors a key area in lung anticancer drug discovery.
Previously we isolated antibiotic producing bacteria as a part of the Tiny Earth® network and
screened their media supernatants for the ability to inhibit cancer stem cells using a
tumorsphere assay. One supernatant inhibited breast, prostate, and lung cancer stem cells. In
the present study, we find that this antibiotic active supernatant selectively inhibits A549 lung
cancer stem cells over bulk A549 lung cancer cells.

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