Ramucirumab: targeting angiogenesis in the treatment of gastric cancer

Oncostatin M Receptor-targeted antibodies suppress STAT3 signaling and inhibit ovarian cancer growth

While patients with advanced ovarian cancer may respond initially to treatment, disease relapse is common and nearly 50% of patients do not survive beyond five years, indicating an urgent need for improved therapies. To identify new therapeutic targets, we performed single cell and nuclear RNA-seq dataset analyses on 17 human ovarian cancer specimens, revealing the oncostatin M receptor (OSMR) as highly expressed in ovarian cancer cells. Conversely, oncostatin M (OSM), the ligand of OSMR, was highly expressed by tumor-associated macrophages and promoted proliferation and metastasis in cancer cells. Ovarian cancer cell lines and additional patient samples also exhibited elevated levels of OSMR when compared to other cell types in the tumor microenvironment or to normal ovarian tissue samples. OSMR was found to be important for ovarian cancer cell proliferation and migration. Binding of OSM to OSMR caused OSMR-IL6ST dimerization, which is required to produce oncogenic signaling cues for prolonged STAT3 activation. Human monoclonal antibody clones B14 and B21 directed to the extracellular domain of OSMR abrogated OSM-induced OSMR-IL6ST heterodimerization, promoted the internalization and degradation of OSMR, and effectively blocked OSMR-mediated signaling in vitro. Importantly, these antibody clones inhibited the growth of ovarian cancer cells in vitro and in vivo by suppressing oncogenic signaling through OSMR and STAT3 activation. Collectively, this study provides a proof of principle that anti-OSMR antibody can mediate disruption of OSM-induced OSMR-IL6ST dimerization and oncogenic signaling, thus documenting the pre-clinical therapeutic efficacy of human OSMR antagonist antibodies for immunotherapy in ovarian cancer.

Exosomes Carrying MicroRNA-155 Target Forkhead Box O3 of Endothelial Cells and Promote Angiogenesis in Gastric Cancer

Gastric cancer (GC) has a poor prognosis due to its relentless proliferation and metastasis. One of the reasons for this plight is the formidable angiogenesis ability of GC. Considering the important role of cancer exosomes as carriers and communicators in the tumor microenvironment, we explored the role of exosome-microRNA (miRNA) in regulating angiogenesis. Western blotting and quantitative real-time PCR were used to measure the protein and mRNA levels of the miRNA target gene. To detect changes in cellular biological functions, we pretreated human umbilical vein endothelial cells (HUVECs) that were severally cocultured with GC-derived exosomes and transfected them with different miRNAs directly. Also, we used the mouse xenograft model to verify the effect of miR-155 on angiogenesis of GC tissues in vivo. Our study confirmed that miR-155, as a driver of angiogenesis, encapsulated by exosomes from GC can enhance the generation of new vessels for GC in vitro through inhibiting the expression of Forkhead box O3 (FOXO3a) protein, which led to the progression of GC. Therefore, miR-155 is probable to become a potential biomarker for the detection of migration and angiogenesis of GC, and serves as a novel target for anti-angiogenesis therapy.

TP53 Alterations Correlate with Response to VEGF/VEGFR Inhibitors: Implications for Targeted Therapeutics

TP53 tumor-suppressor gene mutations are among the most frequent abnormalities in cancer, affecting approximately 40% of patients. Yet, there is no accepted way to target these alterations in the clinic. At the same time, antagonists of VEGFR or its ligand are best-selling oncology drugs, with multiple, expensive compounds approved. Although only a subset of patients benefit from these antiangiogenesis agents, no relevant biomarker has been identified. Interestingly, TP53 mutations upregulate VEGF-A and VEGFR2. We prospectively enrolled 500 patients, to be interrogated by comprehensive genomic profiling (CGP) (next-generation sequencing, 236 genes), and to be matched, whenever possible, with targeted agents. Herein, we analyze outcomes based on VEGF/VEGFR inhibitor treatment and presence of TP53 mutations. Of the 500 patients, 188 (37.6%; with ≥1 alteration) were treated; 106 (56% of 188) had tumors that harbored TP53 mutations. VEGF/VEGFR inhibitor therapy was independently associated with improvement in all outcome parameters [rate of stable disease (SD) ≥6 months/partial and complete remission (PR/CR); (31% versus 7%; TP53-mutant patients (who received no other molecular-matched agents) treated with versus without VEGF/VEGFR inhibitors), time-to-treatment failure, and overall survival (multivariate analysis: all P ≤ 0.01)] for the patients harboring TP53-mutant cancers, but improvement was not seen in any of these parameters for patients with TP53 wild-type neoplasms. We conclude that TP53 mutations predict sensitivity to VEGF/VEGFR inhibitors in the clinic. TP53 alterations may therefore be a ready biomarker for treatment with antiangiogenesis agents, a finding of seminal importance across the cancer field. Mol Cancer Ther; 15(10); 2475-85. ©2016 AACR.

Clinical pharmacokinetics and pharmacodynamics of ramucirumab in the treatment of colorectal cancer

INTRODUCTION

Colorectal cancer is the third most common cancer worldwide. The prognosis of colorectal cancer patients still remains dismal and half of them will develop metastatic disease. Angiogenesis plays an essential role in colorectal tumorigenesis, and the VEGF pathway is one of the targets that has been validated up to now. The use of antiangiogenics along with chemotherapy has become an accepted standard for colorectal cancer.

AREAS COVERED

This review discusses the efficacy and safety profile of ramucirumab, a fully human immunoglobulin G1 monoclonal antibody against the vascular endothelial growth factor receptor-2 (VEGFR-2), for the treatment of second-line metastatic colorectal cancer upon progression to first-line chemotherapy including anti-angiogenics.

EXPERT OPINION

Ramucirumab in combination with chemotherapy represents a valid option in second-line treatment of advanced colorectal cancer patients, who progressed on previous bevacizumab-based combinations. This agent demonstrates a similar benefit in terms of overall survival to other angiogenesis inhibitors (bevacizumab and ziv-aflibercept) used in this setting.