The nontaxane microtubule inhibitor
eribulin is an approved therapeutic for metastatic
breast cancer and
liposarcoma.
Eribulin was previously tested in unselected patients with
lung cancer and yielded a modest objective response rate of ∼5%-12%. Because
lung cancers represent diverse histologies and driving oncogenic mutations, we postulated that
eribulin may exhibit properties of a precision oncology agent with a previously undefined specificity for a molecularly distinct subset of
lung cancers. Herein, we screened a panel of 44 non-small cell and
small-cell lung cancer cell lines for in vitro growth sensitivity to
eribulin. The results revealed a greater than 15,000-fold range in
eribulin sensitivity (IC50 = 0.005-89 nM) among the cell lines that was not correlated with their sensitivity to the
taxane-based inhibitor
paclitaxel. The quartile of cell lines exhibiting the lowest
eribulin IC50 values was not enriched for specific histologies, epithelial-mesenchymal differentiation, or specific oncogene drivers but was significantly enriched for nonsense/frameshift TP53 mutations and low-TP53
mRNA but not missense TP53 mutations. By comparison, the mutation status of
cyclin-dependent kinase inhibitor 2A, STK11, and KEAP1 was not associated with
eribulin sensitivity. Finally, the highest
eribulin IC50 quartile (>1 nM) exhibited significantly elevated
mRNA expression of the drug pump,
ATP binding cassette B1, defined resistance mechanism to
eribulin, and
paclitaxel. The findings support further investigations into basic mechanisms by which complete lack of TP53 function regulates anticancer activity of
eribulin and the potential utility of TP53 null phenotypes distinct from TP53 missense mutations as a
biomarker of response in patients with
lung cancer. SIGNIFICANCE STATEMENT: Distinct from precision oncology agents that are matched to
cancers bearing oncogenically activated versions of their targets, microtubule inhibitors, such as
eribulin, are deployed in an unselected manner. The results in this study demonstrate that
lung cancer cell lines exhibiting the highest sensitivity to
eribulin bear TP53 null phenotypes, supporting a rationale to consider the status of this
tumor suppressor in the clinical setting.