crizotinib and Triple-Negative-Breast-Neoplasms

Rearrangements of the anaplastic lymphoma kinase (ALK) gene are present in 3-5% of non-small-cell lung cancer (NSCLC), while it was 0.2% in NSCLC tumors. Due to its low frequency, it is extremely challenging to conduct randomized clinical trials of ALK-targeted therapies in NSCLC tumors. In the present case, we describe the first reported case of triple-negative breast cancer (TNBC) harboring the ALK fusion mutation that responded to ALK-targeted therapy after progression with two lines of chemotherapy. Searching for ALK gene rearrangement or other fusion, especially in patients with chemotherapy-resistant TNBC, opens the door to new treatment strategies.

Topics: Carcinoma, Non-Small-Cell Lung; Crizotinib; Gene Rearrangement; Humans; Lung Neoplasms; Protein Kinase Inhibitors; Pyrazoles; Pyridines; Receptor Protein-Tyrosine Kinases; Triple Negative Breast Neoplasms

Targeting of somatic MET mutations using crizotinib has led to strong clinical responses, most frequently in patients with lung cancer, raising the possibility of adopting similar treatment strategies in patients with MET alterations in other cancer types.. We describe a patient with advanced triple-negative breast cancer with a 30-fold amplification of MET. Next-generation sequencing of pre- and postprogression biopsies was performed to identify the resistance mechanism emerging after an initial exceptional response to crizotinib. The response of the resistance mutant to type I and II MET inhibitors was assessed in cultured cells.. After progressing on crizotinib, a MET-D1228N mutation was detected, which is located in the crizotinib-binding region of the MET kinase domain. Experimental studies demonstrated that this mutation confers complete resistance to crizotinib yet retains cabozantinib sensitivity. Treatment of the patient with cabozantinib led to a subjective improvement in clinical symptoms, but the patient progressed after 7 weeks.. Although MET mutations are rare in breast cancer, these patients may experience substantial clinical benefit from crizotinib treatment. Nevertheless, drug resistance owing to on-target MET mutations will likely be frequently encountered and comprehensive mechanistic studies to assess sensitivity of these mutants to a series of potential second-line therapies may help guide subsequent treatment for these patients.

Topics: Adult; Amino Acid Substitution; Anilides; Biopsy; Breast; Crizotinib; Disease Progression; DNA Mutational Analysis; Drug Resistance, Neoplasm; Female; Gene Amplification; Humans; Male; Positron Emission Tomography Computed Tomography; Primary Cell Culture; Protein Kinase Inhibitors; Proto-Oncogene Proteins c-met; Pyridines; Treatment Outcome; Triple Negative Breast Neoplasms; Tumor Cells, Cultured

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer diagnosed in more than 200,000 women each year and is recalcitrant to targeted therapies. Although TNBCs harbor multiple hyperactive receptor tyrosine kinases (RTKs), RTK inhibitors have been largely ineffective in TNBC patients thus far. We developed a broadly effective therapeutic strategy for TNBC that is based on combined inhibition of receptors that share the negative regulator PTPN12. Previously, we and others identified the tyrosine phosphatase PTPN12 as a tumor suppressor that is frequently inactivated in TNBC. PTPN12 restrains several RTKs, suggesting that PTPN12 deficiency leads to aberrant activation of multiple RTKs and a co-dependency on these receptors. This in turn leads to the therapeutic hypothesis that PTPN12-deficient TNBCs may be responsive to combined RTK inhibition. However, the repertoire of RTKs that are restrained by PTPN12 in human cells has not been systematically explored. By methodically identifying the suite of RTK substrates (MET, PDGFRβ, EGFR, and others) inhibited by PTPN12, we rationalized a combination RTK-inhibitor therapy that induced potent tumor regression across heterogeneous models of TNBC. Orthogonal approaches revealed that PTPN12 was recruited to and inhibited these receptors after ligand stimulation, thereby serving as a feedback mechanism to limit receptor signaling. Cancer-associated mutation of PTPN12 or reduced PTPN12 protein levels diminished this feedback mechanism, leading to aberrant activity of these receptors. Restoring PTPN12 protein levels restrained signaling from RTKs, including PDGFRβ and MET, and impaired TNBC survival. In contrast with single agents, combined inhibitors targeting the PDGFRβ and MET receptors induced the apoptosis in TNBC cells in vitro and in vivo. This therapeutic strategy resulted in tumor regressions in chemo-refractory patient-derived TNBC models. Notably, response correlated with PTPN12 deficiency, suggesting that impaired receptor feedback may establish a combined addiction to these proto-oncogenic receptors. Taken together, our data provide a rationale for combining RTK inhibitors in TNBC and other malignancies that lack receptor-activating mutations.

Topics: Animals; Cell Line, Tumor; Cell Survival; Crizotinib; Female; Humans; Mice, Nude; Mutation; Phosphorylation; Protein Tyrosine Phosphatase, Non-Receptor Type 12; Receptor Protein-Tyrosine Kinases; Receptors, Cell Surface; Signal Transduction; Sunitinib; Triple Negative Breast Neoplasms; Xenograft Model Antitumor Assays