Mechanisms of the proteinuria induced by Rho GTPases.

Podocytes are highly differentiated cells that play an important role in maintaining glomerular filtration barrier integrity; a function regulated by small GTPase proteins of the Rho family. To investigate the role of Rho A in podocyte biology, we created transgenic mice expressing doxycycline-inducible constitutively active (V14 Rho) or dominant-negative Rho A (N19 Rho) in podocytes. Specific induction of either Rho A construct in podocytes caused albuminuria and foot process effacement along with disruption of the actin cytoskeleton as evidenced by decreased expression of the actin-associated protein synaptopodin. The mechanisms of these adverse effects, however, appeared to be different. Active V14 Rho enhanced actin polymerization, caused a reduction in nephrin mRNA and protein levels, promoted podocyte apoptosis, and decreased endogenous Rho A levels. In contrast, the dominant-negative N19 Rho caused a loss of podocyte stress fibers, did not alter the expression of either nephrin or Rho A, and did not cause podocyte apoptosis. Thus, our findings suggest that Rho A plays an important role in maintaining the integrity of the glomerular filtration barrier under basal conditions, but enhancement of Rho A activity above basal levels promotes podocyte injury.

Seven-Year Follow-Up Analysis of Adjuvant Paclitaxel and Trastuzumab Trial for Node-Negative, Human Epidermal Growth Factor Receptor 2-Positive Breast Cancer.

PURPOSE: The Adjuvant Paclitaxel and Trastuzumab trial was designed to address treatment of patients with small human epidermal growth factor receptor 2 (HER2)-positive breast cancer. The primary analysis of the Adjuvant Paclitaxel and Trastuzumab trial demonstrated a 3-year disease-free survival (DFS) of 98.7%. In this planned secondary analysis, we report longer-term outcomes and exploratory results to characterize the biology of small HER2-positive tumors and genetic factors that may predispose to paclitaxel-induced peripheral neuropathy (TIPN). PATIENTS AND METHODS: In this phase II study, patients with HER2-positive breast cancer with tumors 3 cm or smaller and negative nodes received paclitaxel (80 mg/m2) with trastuzumab for 12 weeks, followed by trastuzumab for 9 months. The primary end point was DFS. Recurrence-free interval (RFI), breast cancer-specific survival, and overall survival (OS) were also analyzed. In an exploratory analysis, intrinsic subtyping by PAM50 (Prosigna) and calculation of the risk of recurrence score were performed on the nCounter analysis system on archival tissue. Genotyping was performed to investigate TIPN. RESULTS: A total of 410 patients were enrolled from October 2007 to September 2010. After a median follow-up of 6.5 years, there were 23 DFS events. The 7-year DFS was 93% (95% CI, 90.4 to 96.2) with four (1.0%) distant recurrences, 7-year OS was 95% (95% CI, 92.4 to 97.7), and 7-year RFI was 97.5% (95% CI, 95.9 to 99.1). PAM50 analyses (n = 278) showed that most tumors were HER2-enriched (66%), followed by luminal B (14%), luminal A (13%), and basal-like (8%). Genotyping (n = 230) identified one single-nucleotide polymorphism, rs3012437, associated with an increased risk of TIPN in patients with grade 2 or greater TIPN (10.4%). CONCLUSION: With longer follow-up, adjuvant paclitaxel and trastuzumab is associated with excellent long-term outcomes. Distribution of PAM50 intrinsic subtypes in small HER2-positive tumors is similar to that previously reported for larger tumors.

Beneficial effects of the Rho kinase inhibitor Y27632 in murine puromycin aminonucleoside nephrosis.

BACKGROUND AND AIMS: Rho kinase (ROCK) inhibition reduces systemic blood pressure (BP) and decreases renal damage in animal models of kidney disease. The aim of this study was to determine if ROCK inhibition might have beneficial effects in glomerular disease processes that are independent of systemic BP. METHODS: We investigated the effects of the ROCK inhibitor Y27632 and hydralazine in murine puromycin aminonucleoside (PAN) nephrosis. RESULTS: Treatment with either Y27632 or hydralazine similarly reduced systolic BP compared to vehicle-treated controls. Seven days after treatment with PAN, albuminuria, proteinuria and effacement of podocyte foot processes were significantly reduced in Y27632- and hydralazine-treated mice compared to vehicle-treated animals. Treatment with PAN significantly reduced expression of the podocyte proteins nephrin and Neph1, and the loss of glomerular nephrin was attenuated by treatment with Y27632 but not by treatment with hydralazine. In cultured podocytes, PAN potently activated both Rho and ROCK, and PAN-induced ROCK activation was prevented by Y27632. CONCLUSIONS: The ROCK inhibitor Y27632 attenuated glomerular nephrin loss in murine PAN nephrosis independent of its effects on systemic BP.

Circulating tumor cells versus imaging--predicting overall survival in metastatic breast cancer.

PURPOSE: The presence of >or=5 circulating tumor cells (CTC) in 7.5 mL blood from patients with measurable metastatic breast cancer before and/or after initiation of therapy is associated with shorter progression-free and overall survival. In this report, we compared the use of CTCs to radiology for prediction of overall survival. EXPERIMENTAL DESIGN: One hundred thirty-eight metastatic breast cancer patients had imaging studies done before and a median of 10 weeks after the initiation of therapy. All scans were centrally reviewed by two independent radiologists using WHO criteria to determine radiologic response. CTC counts were determined approximately 4 weeks after initiation of therapy. Specimens were analyzed at one of seven laboratories and reviewed by a central laboratory. RESULTS: Interreader variability for radiologic responses and CTC counts were 15.2% and 0.7%, respectively. The median overall survival of 13 (9%) patients with radiologic nonprogression and >or=5 CTCs was significantly shorter than that of the 83 (60%) patients with radiologic nonprogression and <5 CTCs (15.3 versus 26.9 months; P=0.0389). The median overall survival of the 20 (14%) patients with radiologic progression and <5 CTCs was significantly longer than the 22 (16%) patients with >or=5 CTCs that showed progression by radiology (19.9 versus 6.4 months; P=0.0039). CONCLUSIONS: Assessment of CTCs is an earlier, more reproducible indication of disease status than current imaging methods. CTCs may be a superior surrogate end point, as they are highly reproducible and correlate better with overall survival than do changes determined by traditional radiology.

Circulating tumor cells: a novel prognostic factor for newly diagnosed metastatic breast cancer.

PURPOSE: Metastatic breast cancer (MBC) is incurable; its treatment is palliative. We investigated whether the presence of circulating tumor cells (CTCs) predicts treatment efficacy, progression-free survival (PFS), and overall survival (OS) in patients with newly diagnosed MBC who were about to start first-line therapy. PATIENTS AND METHODS: One hundred seventy-seven patients with measurable MBC were enrolled onto a prospective study. Eighty-three of the 177 patients were entering first-line treatment, and these patients are the focus of this analysis. CTCs from 7.5 mL of whole blood drawn before treatment initiation (baseline) and monthly thereafter for up to 6 months were isolated and enumerated using immunomagnetics. RESULTS: The mean (+/- standard deviation) follow-up time was 11.1 +/- 4.4 months (median, 12.2 months). Forty-three patients (52%) had > or = five CTCs at baseline. The median PFS was 7.2 months (95% CI, 4.9 to 9.4 months), and the median OS was more than 18 months. Patients with > or = five CTCs at baseline and at first follow-up (4 weeks) had a worse prognosis than patients with less than five CTCs (baseline: median PFS, 4.9 v 9.5 months, respectively; log-rank, P = .0014; median OS, 14.2 v > 18 months, respectively; log-rank, P = .0048; first follow-up: median PFS, 2.1 v 8.9 months, respectively; log-rank, P = .0070; median OS, 11.1 v > 18 months, respectively; log-rank, P = .0029). CTCs before and after the initiation of therapy were strong, independent prognostic factors. CONCLUSION: Detection of CTCs before initiation of first-line therapy in patients with MBC is highly predictive of PFS and OS. This technology can aid in appropriate patient stratification and design of tailored treatments.

Trastuzumab and vinorelbine as first-line therapy for HER2-overexpressing metastatic breast cancer: multicenter phase II trial with clinical outcomes, analysis of serum tumor markers as predictive factors, and cardiac surveillance algorithm.

PURPOSE: Trastuzumab-based therapy improves survival for women with human epidermal growth factor receptor 2 (HER2)-positive advanced breast cancer. We conducted a multicenter phase II study to evaluate the efficacy and safety of trastuzumab combined with vinorelbine, and to assess cardiac surveillance algorithms and tumor markers as prognostic tools. PATIENTS AND METHODS: Patients with HER2-positive (immunohistochemistry [IHC] 3+-positive or fluorescence in situ hybridization [FISH]-positive) metastatic breast cancer received first-line chemotherapy with trastuzumab and vinorelbine to determine response rate. Eligibility criteria were measurable disease and baseline ejection fraction >or= 50%. Serial testing for HER2 extracellular domain (ECD) was performed. RESULTS: Fifty-four women from 17 participating centers were entered onto the study. The overall response rate was 68% (95% confidence interval, 54% to 80%). Response rates were not affected by method of HER2 status determination (FISH v IHC) or by prior adjuvant chemotherapy. Median time to treatment failure was 5.6 months; 38% of patients were progression free after 1 year. Concurrent therapy was quite feasible with maintained dose-intensity. Patients received both chemotherapy and trastuzumab on 90% of scheduled treatment dates. Two patients experienced cardiotoxicity in excess of grade 1; one patient experienced symptomatic heart failure. A surveillance algorithm of screening left ventricular ejection fraction (LVEF) at 16 weeks successfully identified women at risk for experiencing cardiotoxicity. Other acute and chronic side effects were tolerable. Lack of decline in HER2 ECD during cycle 1 predicted tumor progression. CONCLUSION: Trastuzumab and vinorelbine constitute effective and well-tolerated first-line treatment for HER2-positive metastatic breast cancer. Patients with normal LVEF can be observed with surveillance of LVEF at 16 weeks to identify those at risk for cardiotoxicity.

A prospective randomized pilot study to evaluate predictors of response in serial core biopsies to single agent neoadjuvant doxorubicin or paclitaxel for patients with locally advanced breast cancer.

INTRODUCTION: Response to neoadjuvant chemotherapy for locally advanced breast cancer can be correlated with long-term outcomes. Surrogate end-point biomarkers may be used to assess response to the treatment. Most reported studies assessed the effects of combination chemotherapy. We assessed the feasibility of obtaining serial core breast biopsies, and correlated rates of apoptosis, proliferation, and expression of related proteins at baseline, during, and after neoadjuvant single agent chemotherapy for locally advanced breast cancer with response. EXPERIMENTAL DESIGN: Women with a histologically confirmed unresected T(3) or T(4) infiltrating carcinoma of the breast were eligible. The first 20 patients received three cycles of doxorubicin 90 mg/m(2) followed by three cycles of paclitaxel 250 mg/m(2), or the reverse. Nine women received four cycles of each (doxorubicin 60 mg/m(2) and paclitaxel 175 mg/m(2)). Cycles were administered 14 days apart with filgastrim. End points included: (a). clinical and pathological response; (b). serial apoptotic [terminal deoxynucleotidyl transferase (Tdt)-mediated nick end labeling] and proliferation (immunohistochemistry, IHC) rates; and (c). expression (IHC) of estrogen receptor, HER2, bcl2, and p53. RESULTS: From April 1997 to June 2001, 29 women were randomized. Twelve patients (42%) had a clinical complete response (cCR), and 16 (55%) had a clinical partial response. Five women (17%) had a pathological complete response, 7 (24%) had microscopic residual disease, and 17 (58%) had macroscopic residual disease. Higher baseline apoptosis and proliferation were associated with an improved pathological response (P = 0.006 and 0.003, respectively). Among 14 evaluable patients, apoptosis increased in women who had a cCR to the first agent but not in women without a cCR. Estrogen receptor-positive patients had a worse pathological response (P = 0.004). CONCLUSIONS: The selected regimen is efficacious. It is feasible to obtain serial core biopsies that are informative for studies of apoptosis and IHC. This clinical design can serve as a model for combining standard chemotherapy and novel agents.