Abstract: The prime obstacle to achieving an effective treatment for cancer is that of eradicating tumors without harming healthy organs and cells of the patient. The concept of utilizing biological agents for delivery of therapeutic genes to patients to kill cancer cells has been under investigation for two decades, which exploits the natural ability of disease causing microbes to invade human cells. Safety-modified versions of pathogenic viruses or bacteria can deposit genes and induce production of anti-cancer agents upon administration to tumors and promising clinical trial successes have been achieved with various types of gene delivery vehicles. Bacteria present an attractive class of gene vectors, possessing a natural ability to grow specifically within tumors following intravenous (IV) injection. Several species such as Clostridium and Salmonella have been examined in clinical trials. However, as foreign, disease-causing bugs, their inherent toxicity has outweighed therapeutic responses in patients, despite efforts to reduce toxicity through genetic modification. A promising alternative exploits non-pathogenic bacterial species that have an existing natural relationship with humans. Our recent study (Cronin et al., 2010) has demonstrated that IV injection or ingestion of a species of probiotic bacterium, Bifidobacterium breve, in high numbers, results in trafficking of the bacteria throughout the body and accumulation specifically within cancerous tissue. ... Read more

Abstract: Cancer vaccines consisting of intact tumor cells genetically modified to secrete the cytokine granulocyte-macrophage colony-stimulating factor (GM-CSF) have undergone extensive preclinical development. These vaccines induce the massive accumulation of dendritic cells at the intradermal injection site, which engulf, process, and present tumor antigens to activate tumor-specific T cells. Early phase clinical testing demonstrated promising evidence of safety and bioactivity, although initial phase III clinical trials were unsuccessful. Together, the preclinical and clinical data argue for the continued clinical development of these vaccines, integrating them with standard and novel cancer therapeutics that enhance vaccine activity by overcoming immune tolerance and suppression, and/or augmenting co-stimulatory pathways of T cell activation. ... Read more

Abstract: Adoptive transfer of T cells can enhance immune-mediated elimination of tumor cells and provides a specific, non-toxic cancer therapy. This approach has been effective in treating some hematologic and solid malignancies. In addition, the ability to genetically modify T cells to enhance their activity and persistence as well as overcome tumor immune evasion mechanisms has the potential to increase the success of these therapies in a wide range of tumors. In this review we discuss methods for gene transfer and specific modifications that have been made to T cells. ... Read more

Abstract: Chemotherapy-resistant B-cell hematologic malignancies may be cured with allogeneic hematopoietic stem cell transplantation (HSCT), demonstrating the potential susceptibility of these tumors to donor T-cell mediated immune responses. However, high rates of transplant-related morbidity and mortality limit this approach. For this reason, there is an urgent need for less-toxic forms of immune-based cellular therapy to treat these malignancies. Adoptive transfer of autologous T cells genetically modified to express chimeric antigen receptors (CARs) targeted to specific tumor-associated antigens represents an attractive means of overcoming the limitations of conventional HSCT. To this end, investigators have generated CARs targeted to various antigens expressed by B-cell malignancies, optimized the design of these CARs to enhance receptor mediated T cell signaling, and demonstrated significant anti-tumor efficacy of the resulting CAR modified T cells both in vitro and in vivo mouse tumor models. These encouraging preclinical data have justified the translation of this approach to the clinical setting with currently 12 open clinical trials and one completed clinical trial treating various B-cell malignancies utilizing CAR modified T cells targeted to either the CD19 or CD20 B-cell specific antigens. ... Read more

Abstract: Standard anti-cancer therapeutic modalities like chemotherapy and radiotherapy evoke host's reactions that include involvement of the immune system. Elucidation of these mechanisms offers the double advantage of enabling a more rational choice of cytotoxic therapy and exploring the combination with immunotherapy. Radiotherapy, a well established local anti-cancer approach, is a particularly interesting partner for immunotherapy, since it can be harnessed to specifically modify the immunogenicity of the primary tumor and its microenvironment, in the attempt to generate an in situ immunization against a patient's own cancer. ... Read more

Abstract: Ovarian cancer is the leading cause of cancer death among gynecological malignances. Despite the initial successful multimodality therapy with cytoreductive surgery and subsequent combination chemotherapy, most patients with advanced disease will ultimately relapse and become incurable. For this reason novel therapeutic approaches for the treatment of this malignancy are urgently needed. Adoptive transfer of genetically modified autologous tumor-reactive T cells is a promising novel antitumor therapy for many cancers. T cells may be genetically modified ex vivo to express chimeric antigen receptors (CARs), which are artificial T cell receptors targeted to specific tumor antigens. The resulting T cells are thus programmed to recognize tumor cells. Ovarian carcinomas in particular appear to be suited to this therapeutic approach based on the fact that these tumors are relatively immunogenic, inducing an endogenous T cell response. Furthermore, the degree to which this endogenous T cell mediated immune response is evident correlates to long-term patient prognosis following surgery and chemotherapy. To this end, adoptive T cell immunotherapy strategies for the treatment of ovarian carcinomas appear to be particularly promising and are currently being investigated at several centers in both pre-clinical and clinical settings. ... Read more

Abstract: In the past 5 years the management of metastatic renal cell carcinoma has been revolutionized by the advent of anti-angiogenic treatments, particularly the multi-targeted kinase inhibitors. This revolution has put standard and experimental immunotherapy in the shade. However, it is likely that a subset of patients with advanced kidney cancer is still best served by immunotherapy. This article summarizes promising novel immunotherapeutic techniques to identify those patients who will benefit and to optimize outcomes for patients using novel immunotherapeutic approaches. ... Read more

Abstract: Natural killer cells were first described in the early 1970s on a functional basis according to their ability to lyse tumor cells in the absence of prior stimulation. Since their discovery, NK cells have been shown to have other important functions that led to the use of NK cells as a form of adoptive immunotherapy. Over the next 5-10 years, with the advances in the field of NK cells we will undoubtedly see the use of allogeneic and autologous NK cells at the forefront of cancer immunotherapy. ... Read more

Abstract: The immune system usually detects and destroys pre-malignant cells, which are cells that have initiated oncogenic transformation. To fulfill this role, the immune system must distinguish between normal and transformed cells rather than between self and non-self. A large body of novel research studies illuminates the close relation between immunosurveillance and oncogenesis, suggesting new strategies for reestablishing the immune response against established tumors. ... Read more

Abstract: DNA vaccines generate both T cell and B cell (or antibody) mediated immunities. Methods such as prime-boost regimens and the use of adjuvants in combination with the DNA vaccine have enhanced the therapeutic effectiveness of DNA vaccines in the treatment of cancer, infectious diseases, autoimmune diseases, asthma, and other conditions. ... Read more