Biomedical subjects

Karen A Glatt

Publications and source records attributed to Karen A Glatt.

4 recordsLinked to original sources

PubMed2006

Non-small-cell lung cancer and Ba/F3 transformed cells harboring the ERBB2 G776insV_G/C mutation are sensitive to the dual-specific epidermal growth factor receptor and ERBB2 inhibitor HKI-272.

Mutation-specific cancer therapy has shown promising clinical efficacy. In non-small-cell lung cancer (NSCLC), the presence of mutations in the epidermal growth factor receptor (EGFR) tyrosine kinase correlates with clinical response to small-molecule tyrosine kinase inhibitors. Here, we show that cells harboring the G776insV_G/C mutation in the related ERBB2 tyrosine kinase (also known as HER2 or Neu), present in a small percentage of NSCLCs, are sensitive to HKI-272, an irreversible dual-specific kinase inhibitor targeting both EGFR and ERBB2. In the ERBB2-mutant NCI-H1781 cell line, HKI-272 treatment inhibited proliferation by induction of G(1) arrest and apoptotic cell death. Furthermore, HKI-272 abrogated autophosphorylation of both ERBB2 and EGFR. Finally, Ba/F3 murine pro-B cells, engineered to express mutant ERBB2, became independent of interleukin-3 and sensitive to HKI-272. Thus, the subset of NSCLC patients with tumors carrying the ERBB2 G776insV_G/C mutation may benefit from treatment with HKI-272.

Carcinoma, Non-Small-Cell Lung↗

PubMed2006

Sensitive mutation detection in heterogeneous cancer specimens by massively parallel picoliter reactor sequencing.

The sensitivity of conventional DNA sequencing in tumor biopsies is limited by stromal contamination and by genetic heterogeneity within the cancer. Here, we show that microreactor-based pyrosequencing can detect rare cancer-associated sequence variations by independent and parallel sampling of multiple representatives of a given DNA fragment. This technology can thereby facilitate accurate molecular diagnosis of heterogeneous cancer specimens and enable patient selection for targeted cancer therapies.

Base Sequence↗

PubMed2006

Epidermal growth factor receptor variant III mutations in lung tumorigenesis and sensitivity to tyrosine kinase inhibitors.

The tyrosine kinase inhibitors gefitinib (Iressa) and erlotinib (Tarceva) have shown anti-tumor activity in the treatment of non-small cell lung cancer (NSCLC). Dramatic and durable responses have occurred in NSCLC tumors with mutations in the tyrosine kinase domain of the epidermal growth factor receptor (EGFR). In contrast, these inhibitors have shown limited efficacy in glioblastoma, where a distinct EGFR mutation, the variant III (vIII) in-frame deletion of exons 2-7, is commonly found. In this study, we determined that EGFRvIII mutation was present in 5% (3/56) of analyzed human lung squamous cell carcinoma (SCC) but was not present in human lung adenocarcinoma (0/123). We analyzed the role of the EGFRvIII mutation in lung tumorigenesis and its response to tyrosine kinase inhibition. Tissue-specific expression of EGFRvIII in the murine lung led to the development of NSCLC. Most importantly, these lung tumors depend on EGFRvIII expression for maintenance. Treatment with an irreversible EGFR inhibitor, HKI-272, dramatically reduced the size of these EGFRvIII-driven murine tumors in 1 week. Similarly, Ba/F3 cells transformed with the EGFRvIII mutant were relatively resistant to gefitinib and erlotinib in vitro but proved sensitive to HKI-272. These findings suggest a therapeutic strategy for cancers harboring the EGFRvIII mutation.

Animals↗

PubMed2006

Epidermal growth factor receptor activation in glioblastoma through novel missense mutations in the extracellular domain.

BACKGROUND: Protein tyrosine kinases are important regulators of cellular homeostasis with tightly controlled catalytic activity. Mutations in kinase-encoding genes can relieve the autoinhibitory constraints on kinase activity, can promote malignant transformation, and appear to be a major determinant of response to kinase inhibitor therapy. Missense mutations in the EGFR kinase domain, for example, have recently been identified in patients who showed clinical responses to EGFR kinase inhibitor therapy. METHODS AND FINDINGS: Encouraged by the promising clinical activity of epidermal growth factor receptor (EGFR) kinase inhibitors in treating glioblastoma in humans, we have sequenced the complete EGFR coding sequence in glioma tumor samples and cell lines. We identified novel missense mutations in the extracellular domain of EGFR in 13.6% (18/132) of glioblastomas and 12.5% (1/8) of glioblastoma cell lines. These EGFR mutations were associated with increased EGFR gene dosage and conferred anchorage-independent growth and tumorigenicity to NIH-3T3 cells. Cells transformed by expression of these EGFR mutants were sensitive to small-molecule EGFR kinase inhibitors. CONCLUSIONS: Our results suggest extracellular missense mutations as a novel mechanism for oncogenic EGFR activation and may help identify patients who can benefit from EGFR kinase inhibitors for treatment of glioblastoma.

Animals↗