Augmentation of IFN-γ+ CD8+ T cell responses correlates with survival of HCC patients on sorafenib therapy.

BACKGROUNDSorafenib has been shown to reduce the extent of immunosuppression in patients with hepatocellular carcinoma (HCC). The rationale of this investigation was to identify biomarkers that can predict treatment efficacy of sorafenib in HCC patients and to unravel the mechanism by which sorafenib impedes immune suppression mediated by distinct immunosuppressive cell subsets.METHODSWith informed consent, blood samples were collected from 30 patients with advanced HCC, at baseline and 2 time points after initiation of sorafenib treatment. The frequency of PD-1+ T cells, ERK2 phosphorylation on flt-3+ Tregs and MDSCs, and T effector cell function were quantified by using flow cytometry.RESULTSElevated levels of CD8+Ki67+ T cells producing IFN-γ were associated with improved progression-free survival and overall survival (OS). High frequencies of these T cells were correlated with significantly reduced risk of death over time. Patients with an increased pretreatment T effector/Treg ratio showed significant improvement in OS. ERK+flt-3+ Tregs and MDSCs were significantly decreased after sorafenib therapy. Increased numbers of baseline flt-3+p-ERK+ MDSCs were associated with survival benefit of patients.CONCLUSIONA high baseline CD4+ T effector/Treg ratio is a potential biomarker of prognostic significance in HCC. CD8+Ki67+ T cells producing IFN-γ are a key biomarker of response to sorafenib therapy resulting in survival benefit. The immune modulation resulted from sorafenib-mediated blockade of signaling through the VEGF/VEGFR/flt-3 pathway, affecting ERK phosphorylation. These insights may help identify patients who likely would benefit from VEGFR antagonism and inform efforts to improve the efficacy of sorafenib in combination with immunotherapy.TRIAL REGISTRATIONNCT02072486.FUNDINGNational Comprehensive Cancer Network Oncology Research Program from general research support provided by Bayer US LLC (NCCNSORA0002), National Cancer Institute grant P30CA016056, and pilot funds from Roswell Park Alliance Foundation.

Sorafenib: a clinical and pharmacologic review.

IMPORTANCE OF THE FIELD: Sorafenib is an oral receptor tyrosine kinase inhibitor that inhibits Raf serine/threonine kinases and receptor tyrosine kinases (vascular endothelial growth factor receptors 1, 2, 3 and platelet-derived growth factor-beta, Flt-3 and c-kit) that are implicated in tumorigenesis and tumor progression. Sorafenib is approved for the treatment of advanced inoperable hepatocellular cancer and advanced renal cell cancer. AREAS COVERED IN THIS REVIEW: The findings from the major Phase III studies that led to FDA approval of this drug for the above indications are reviewed. Key aspects of sorafenib pharmacology, dosing in the presence of organ dysfunction, toxicities and weaknesses of the research done so far are summarized. WHAT WILL THE READER GAIN: The reader will have the knowledge of the major studies that form the basis of the clinical use of sorafenib, information on the upcoming Phase III trials that could lead to changes in clinical practice and some insights on aspects of the drugs' mechanism of action and toxicity that still remain unclear. TAKE HOME MESSAGE: Sorafenib is a well-tolerated oral antiangiogenic agent approved for treatment of two angiogenesis-driven cancers. Studies to broaden the clinical indications and increase understanding of the clinical and laboratory biomarkers of response are needed.

Oral transgenic plant-based vaccine for hepatitis B.

In addition to improving vaccine formulations in order to elicit robust and long-lasting immune responses, there is also an increasing need for improving the manner in which these vaccines are delivered. As most current vaccines are administered by injection by a health care giver, there is the ever-present danger of needlestick injuries. Therefore, needle-free vaccinations are a viable option toward limiting needle-associated injuries and additionally increasing compliance with vaccination schedules, as both children and adults have an aversion to injections. Noninvasive methods of vaccination will also facilitate speed of vaccine delivery and likely also reduce cost, both important factors for health care in developing countries. One alternative to current injectable immunizations is orally delivered vaccines. A specific approach that we and others are evaluating is the use of transgenic plant tissue that expresses vaccine antigens for oral immunization. Herein, we review the development of an oral HBV vaccine expressed in transgenic potato tubers and the immune responses generated in human subjects given this novel vaccine.

Plant-derived vaccines: a look back at the highlights and a view to the challenges on the road ahead.

The sobering reality is that each year, 33 million children remain unvaccinated for vaccine-preventable diseases. Universal childhood vaccination would have profound effects on leveling the health inequities in many parts of the world. As an alternative to administration of vaccines by needle and syringe, oral vaccines offer significant logistical advantages, as the polio eradication campaign has demonstrated. Over the past decade, the expression of subunit vaccine antigens in plants has emerged as a convenient, safe and potentially economical platform technology, with the potential to provide a novel biotechnological solution to vaccine production and delivery. As this technology has come of age, many improvements have been made on several fronts, as a growing number of research groups worldwide have extensively investigated plants as factories for vaccine production. This review attempts to highlight some of the achievements over the past 15 years, identify some of the potential problems and discuss the promises that this technology could fulfill.

Virus-like particle expression and assembly in plants: hepatitis B and Norwalk viruses.

Expression of vaccine antigens in plants and delivery via ingestion of transgenic plant material has shown promise in numerous pre-clinical animal studies and in a few clinical trials. A number of different viral antigens have been tested, and among the most promising are those that can assemble virus-like particles (VLP), which mimic the form of authentic virions and display neutralizing antibody epitopes. We have extensively studied plant expression, VLP assembly, and immunogenicity of hepatitis B surface antigen (HBsAg) and Norwalk virus capsid protein (NVCP). The HBsAg small protein (S protein) was found by TEM to assemble tubular membrane complexes derived from endoplasmic reticulum in suspension cultured cells of tobacco and soybean, and in potato leaf and tuber tissues. The potato material was immunogenic in mice upon delivery by ingestion. Here we describe the plant expression and immunogenicity of HBsAg middle protein (M protein or pre-S2 + S) which contains additional 55 amino acid pre-S2 region at N-terminus of the S protein. Plant-derived recombinant M protein provoked stronger serum antibody responses against HBsAg than did S protein when injected systemically in mice. We discuss implications for use of fusion proteins for enhanced immunogenicity and mucosal targeting of HBsAg, as well as delivery of heterologous fused antigens. NVCP expressed in plants assembled 38 nm virion-size icosahedral (T = 3) VLP, similar to those produced in insect cells. The VLP stimulated serum IgG and IgA responses in mice and humans when they were delivered by ingestion of fresh potato tuber. Here we show that freeze-drying of transgenic NVCP tomato fruit yielded stable preparations that stimulated excellent IgG and IgA responses against NVCP when fed to mice. However, the predominant VLP form in tomato fruit was the small 23 nm particle also observed in insect cell-derived NVCP.