Daniel Arie Haber
Our laboratory is interested in the genetics of human cancer. Current projects include the use of a microfluidic device to capture circulating tumor cells (CTCs) and its application in molecular-directed therapy and in the study of human cancer metastasis.
Activating mutations in the epidermal growth factor receptor (EGFR) were identified in our laboratory in the subset of non-small cell lung cancer (NSCLC) with dramatic responses to the tyrosine kinase inhibitor gefitinib. We have studied mechanisms underlying such oncogene addiction, as well as the pathways that lead to the acquisition of resistance to targeted therapies, including the application of irreversible kinase inhibitors to circumventing mutations that alter drug binding affinity. Following on our efforts to monitor the emergence of drug resistance mutations, we are now collaborating with the Toner and Maheswaran laboratories to characterize novel microfluidic devices capable of isolating CTCs from the blood of cancer patients. Our most advanced version of these CTC-Chips relies upon blood flow through a specialized chamber, which allows the high efficiency separation of antibody-tagged leukocytes, thereby identifying intact CTCs without selection bias. In a series of CTC studies, we have shown that the number of captured CTCs correlates with clinical evidence of tumor response, and that the cells can be used to define molecular markers characteristic of the underlying malignancy, including EGFR mutations and EML4-ALK translocations in lung cancer, and measurements of androgen receptor (AR) activity in prostate cancer. We have applied next generation single-molecule RNA sequencing to identify non-canonical Wnt signaling as a suppressor of anoikis pathways in circulating pancreatic cancer cells, while in melanoma and in glioblastoma, we developed tools to isolate and molecularly characterize CTCs.
Our most recent studies have focused on breast cancer, where we demonstrated treatment-associated epithelial-to-mesenchymal transition (EMT) within CTCs. Using a combination of mouse models and patient-derived studies, we observed that tumor-derived fragments generate CTC-Clusters, which have greatly enhanced metastatic propensity compared with single CTCs. CTC-Clusters are held together by plakoglobin, whose knockdown dramatically suppresses CTC-Cluster formation and metastatic spread of breast cancer cells. Finally, we successfully established long-term in vitro cultures of CTCs from patients with estrogen-receptor positive breast cancer, identifying treatment-associated mutations in the estrogen receptor (ESR1), as well as acquired mutations in drugable therapeutic targets, such as PIK3CA and FGFR. The development of such CTC-derived cultures may enable functional predictive drug testing, combined with detailed genetic analysis of tumor cells sampled noninvasively during the course of cancer treatment.
Current efforts are directed at isolating single CTCs to uncover the heterogeneous nature of these rare metatastic precursors. Further technological improvements in CTC capture and detection are under study for potential applications in early detection of cancer, monitoring tumor genotypes over the course of treatment, and biological characterization of CTCs themselves.
MGH Cancer Center
149 13th Street
Charlestown, MA 02129