Metformin and Angiogenesis in Cancer - Revisited.

Several clinical studies demonstrated that diabetic patients treated with metformin were less likely to develop vascular complications, independent of glycemic control. It was also demonstrated that the large variety of metformin's vascular actions can be seen in nondiabetic conditions. Metformin has an interesting potential to treat vascular dysfunction and tumor angiogenesis in conditions beyond diabetes. Since metformin's use in cancer as a single antiangiogenic agent appears to be a therapeutic disappointment, the use of the drug as part of combination anticancer modality represents a therapeutic challenge. The normalization of vascular dysfunction as a new therapeutic strategy may provide better delivery of conventional anticancer agents to the tumor and disrupted tumor environment. In this review, we will outline the available information from the literature regarding metformin and tumor angiogenesis and suggest eventual experimental and clinical approaches.

Endothelin-1 enriched tumor phenotype predicts breast cancer recurrence.

Introduction. Breast cancer recurrence can develop years after primary treatment. Crosstalk between breast cancer cells and their stromal microenvironment may influence tumor progression. Our primary study aim was to determine whether endothelin-1 (ET-1) expression in tumor and stroma predicts breast cancer relapse. The secondary aim was to determine ET-1/endothelin receptor A (ETAR) role on signaling pathways and apoptosis in breast cancer. Experimental Design. Patients with histologically documented stages I-III invasive breast cancer were included in the study. ET-1 expression by immunohistochemistry (IHC) in tumor cells and stroma was analyzed. Association between ET-1 expression and clinical outcome was assessed using multivariate Cox proportional hazard model. Kaplan-Meier curves were used to estimate disease-free survival (DFS). In addition, the effect of ET-1/ETAR on signaling pathways and apoptosis was evaluated in MCF-7 and MDA-MB-231 breast cancer cells. Results. With a median followup of 7 years, ET-1 non-enriched tumor phenotype had a significant association with favorable disease-free survival (HR = 0.16; 95% CI 0.03-0.77; P value <0.02). ER negativity, advanced stage of disease and ET-1-enriched tumor phenotype were all associated with a higher risk for recurrence. Experimental study demonstrated that ET-1 stimulation promoted Akt activation in MCF-7 and MDA-MB-231 cells. Furthermore, silencing of ETAR induced apoptosis in both hormone receptor negative and hormone receptor positive breast cancer cells. Conclusions. We found ET-1 expression in tumor and stroma to be an independent prognostic marker for breast cancer recurrence. Prospective studies are warranted to examine whether ET-1 expression in tumor/stroma could assist in stratifying patients with hormone receptor positive breast cancer for adjuvant therapy.

HER2 status in elderly women with breast cancer.

OBJECTIVES: HER2 (human epidermal growth factor receptor 2) is an important biomarker in breast cancer, but its prevalence in elderly women is not well established. Previous studies reported HER2 status based on either immunohistochemistry (IHC) or fluorescent in situ hybridization (FISH) interchangeably. However, the tests may give discordant results. We report the prevalence of HER2 amplification in elderly women using only FISH. MATERIALS AND METHODS: We retrospectively identified women 65 years and older undergoing core biopsy, lumpectomy or mastectomy for primary breast malignancy at a single institution between 2009 and 2011. Data collected included age, histopathological type, hormone receptor status, and HER2 status. Descriptive statistics were performed using SAS Software, Version 9.2. RESULTS: One hundred fifty-eight women were included in the study. Most had invasive ductal carcinoma (74.7%), and were positive for either estrogen (ER) or progesterone (PgR) receptors (82.3% and 70.0%, respectively). Only 17% were negative for both ER and PgR; 11.4% were triple negative. Nineteen samples (12.0%) were positive for HER2. In univariate analyses, hormone receptor and HER2 status did not vary with age. When stratified by age, 60% of women with hormone receptor/HER2 positive tumors were younger than 70 years, compared with 22.2-33.3% of women in other subgroups. The difference was not statistically significant (p=0.20). CONCLUSION: This study adds to the knowledge of the biology of breast cancer in elderly women. Triple negative tumor incidence was similar to that previously reported for women under 70 years old, but HER2 positive tumors were less common. Additional prospective studies are needed to confirm our findings.

Phase I study and preliminary pharmacology of the novel innate immune modulator rBBX-01 in gynecologic cancers.

PURPOSE: A recombinant protein product, rBBX-01, is the first innate immunostimulator derived from a protozoan (Eimeria protozoan) and has shown potent preclinical in vivo and in vitro activities. This phase I trial was done to determine the safety and basic pharmacology of rBBX-01. EXPERIMENTAL DESIGN: Eligible patients had recurrent incurable gynecologic malignancies. The study was divided into three components: a starting low-dose phase (0.85, 2.0, and 4.0 microg/m2), an intrapatient dose acceleration phase (4.0-1,024.0 microg/m2), and a high-dose phase (1,000 and 2,000 microg/m2). All treatment doses were administered daily for 5 days. Patients were allowed a second cycle of treatment if there was evidence of response. RESULTS: Sixteen patients received a total of 20 cycles of rBBX-01. All patients tolerated the drug well, exhibiting no local or systemic, acute or delayed, adverse reactions. Plasma levels of rBBX-01 were detectable in all patients over the entire dose range, although changes in the pharmacodynamic marker (interleukin-12) exhibited patient-to-patient variability. Of 14 patients with ovarian, primary peritoneal, or endometrial cancer with elevated CA125 biomarkers at the start of treatment, 4 responded with decreased levels of CA125. One patient showed decreasing CA125 levels for 10 months and received no additional chemotherapy for 11 months. Those patients exhibiting reductions in CA125 also exhibited increased levels of plasma interleukin-12 during the week of therapy. CONCLUSION: The immunostimulator rBBX-01 was safe in multidose regimens in heavily pretreated women. Of the 14 patients with elevated CA125 levels, an approximately 30% response rate was detected. rBBX-01 should receive additional testing in the clinical setting.

Some aspects of the endocrine profile and management of hormone-dependent male breast cancer.

The management of hormone-dependent male breast cancer is insufficiently understood by practicing oncologists. This article provides a review of the endocrine profile of male breast cancer, and outlines the differences between hormone-dependent female and male breast cancers. A concise review of the past, present, and possible future management of hormone-dependent male breast cancer is presented. For a better understanding of this disease, more information on the natural history and biological behaviors of patients with male breast cancer is needed. This could be accomplished by the development of a specific multi-institutional tumor registry and execution of prospective clinical trials.

Protein from intestinal Eimeria protozoan stimulates IL-12 release from dendritic cells, exhibits antitumor properties in vivo and is correlated with low intestinal tumorigenicity.

The small intestine (SI) of vertebrates exhibits low tumorigenesis and rarely supports metastatic growth from distant tumors. Many theories have been proposed to address this phenomenon, but none has been consistently supported. One candidate mechanism is that the vast immunologic compartment of the SI provides a heightened level of tumor immunosurveillance. Consistent with this, we have identified a molecule of low abundance from bovine SI that has the hallmarks of a potent immunostimulant and may be associated with the natural suppression of cancer in the intestinal tract. The protein originates from an endemic gut protozoan, Eimeria spp., and is homologous to the antigen 3-1E previously isolated from the avian apicomplexan E. acervulina. We show here that it is a very potent stimulator of IL-12 release from dendritic cells, upregulates inflammatory modulators in vivo (IL-12, MCP-1, IL-6, TNF-alpha and INF-gamma) and has antitumor properties in mice. In addition, it is synergistic in vitro with anti-CD40 antibody, IFN-gamma, IL-4 and GM-CSF; is active across species barriers in vivo; and has no observable toxicity. Based on these activities, we speculate that it is an inducer of protozoan-targeted innate immunity, which may explain its potential benefit to the intestinal tract and potency as an agent in cancer immunotherapy.

Inhibition of mitogen-activated protein kinase activity of human lymphocytes after oral administration of Oltipraz.

Several preclinical studies indicated that Oltipraz appears to be one of the most potent cancer chemopreventive agents. Pharmacological studies in humans provided substantial amounts of information related to doses and schedules. Oltipraz has been reported to induce phase II drug-metabolizing enzymes. However, its chemopreventive activity suggests that it may also interact with cellular processes associated with cancer cell growth and proliferation. During a clinical trial designed to monitor eventual Oltipraz toxicity in high-risk population for development of lung cancer, we performed companion studies related to cell proliferation. Human lymphocytes were chosen as surrogate tissue to assess the in vivo effects of Oltipraz on cell signaling pathways involved in cell proliferation. The results of this study demonstrate that Oltipraz markedly inhibited the activation state of the extracellular signal-regulated kinases of the mitogen-activated protein kinase family of kinases in lymphocytes of subjects treated with two different doses and schedules of Oltipraz. Individual variations were observed that were not related to Oltipraz dosing or schedule of administration. The results from this study indicate that lymphocytes could be used as surrogate tissue for the development of biomarkers for studies of anticarcinogenic agents.