A Phase I/II study of suberoylanilide hydroxamic acid (SAHA) in combination with trastuzumab (Herceptin) in patients with advanced metastatic and/or local chest wall recurrent HER2-amplified breast cancer: a trial of the ECOG-ACRIN Cancer Research Group (E1104).

PURPOSE: Suberoylanilide hydroxamic acid (SAHA; vorinostat), a small molecule inhibitor of histone deacetylase, attenuates signaling pathways known to confer trastuzumab resistance. A combination of SAHA and trastuzumab may be a promising strategy to improve the efficacy of trastuzumab against breast cancer. In this Phase I/II study, we evaluated the toxicity and response rate after treatment with SAHA and trastuzumab in patients with HER2-overexpressing metastatic breast cancer with trastuzumab-resistant progressive disease. METHODS: In Phase I, the SAHA dose was modified in cohorts of 3-6 patients to find the dose level at which 0 or 1 patients experienced a dose-limiting toxicity (DLT) during the first cycle of therapy. In the Phase II study, response to the recommended dose identified in Phase I was based on the response evaluation criteria in solid tumors. Overall survival and time to progression were also evaluated. RESULTS: The recommended dose was determined to be 200 mg twice a day on days 1-14 and IV trastuzumab 6 mg/kg on day 1 of a 21-day cycle (n = 6). The Phase II study (n = 10) was terminated when the pre-planned efficacy evaluation found that none of the patients in the primary analysis set responded to combination SAHA and trastuzumab treatment. CONCLUSIONS: In patients with HER2-positive metastatic breast cancer who had relapsed or progressed during trastuzumab therapy, we observed no DLTs with SAHA 200 mg twice daily combined with trastuzumab; however, there was insufficient statistical evidence that adding SAHA reversed trastuzumab resistance in these patients.

Mutational studies on single circulating tumor cells isolated from the blood of inflammatory breast cancer patients.

PURPOSE: The molecular characterization of circulating tumor cells (CTCs) is critical to identify the key drivers of cancer metastasis and devising therapeutic approaches, particularly for inflammatory breast cancer (IBC) which is usually diagnosed at advance stages and progresses rapidly. METHODS: Genomic alterations in tumor tissue samples were studied using Foundation One™. Single CTCs were isolated using CellSearch followed by single-cell isolation by DEPArray™. Samples with 20 or more CTCs were chosen to isolate single CTCs using the DEPArray™. RESULTS: Genomic alterations were studied in primary tumor or metastatic sites from 32 IBC patients. Genes with high-frequency mutations were as follows: TP53 (69%), RB1 (16%), PIK3CA (13%), and also ErbB2 (3%). At least once during treatment, CTCs were detected in 26 patients with metastatic IBC, in two patients with locally advanced IBC, and four patients had no detectable CTCs. Per 7.5 mL of blood, fifteen patients (47%) had ≥20 CTCs and six of them were chosen at random to isolate single CTCs. These cells were tested for the presence of TP53, RB1, PIK3CA, and/or ErbB2 mutations previously found in matching tissue biopsies. The isolated CTCs showed the same mutations as primary or metastatic tumor samples. Intra-patient CTC heterogeneity was found by the presence of different CTC subclones, with some CTCs harboring different combinations of mutated and wild-type genes. CONCLUSIONS: Our results indicate that CTCs could represent a non-invasive source of cancer cells from which to determine genetic markers as the disease progresses and identify potential therapeutic targets in IBC patients.

Matrix-regulated integrin αvß5 maintains α5ß1-dependent desmoplastic traits prognostic of neoplastic recurrence.

Desmoplasia, a fibrotic mass including cancer-associated fibroblasts (CAFs) and self-sustaining extracellular matrix (D-ECM), is a puzzling feature of pancreatic ductal adenocarcinoma (PDACs). Conflicting studies have identified tumor-restricting and tumor-promoting roles of PDAC-associated desmoplasia, suggesting that individual CAF/D-ECM protein constituents have distinguishable tumorigenic and tumor-repressive functions. Using 3D culture of normal pancreatic versus PDAC-associated human fibroblasts, we identified a CAF/D-ECM phenotype that correlates with improved patient outcomes, and that includes CAFs enriched in plasma membrane-localized, active α5ß1-integrin. Mechanistically, we established that TGFß is required for D-ECM production but dispensable for D-ECM-induced naïve fibroblast-to-CAF activation, which depends on αvß5-integrin redistribution of pFAK-independent active α5ß1-integrin to assorted endosomes. Importantly, the development of a simultaneous multi-channel immunofluorescence approach and new algorithms for computational batch-analysis and their application to a human PDAC panel, indicated that stromal localization and levels of active SMAD2/3 and α5ß1-integrin distinguish patient-protective from patient-detrimental desmoplasia and foretell tumor recurrences, suggesting a useful new prognostic tool.