Cancer vaccines

Active and passive immunization for cancer

Vaccination started around the 10th century AD as a means of preventing smallpox. By the end of the 19th century such therapeutic vaccines were well established with both active and passive preparations being used in clinical practice. Active immunization involved administering an immunogen that might be live/ attenuated, killed/ inactivated, toxoid or subunit in origin. Passive immunization involved giving pre-formed antibodies, usually to very recently exposed individuals. At about the same time such approaches were also tried to treat a variety of cancers - proof of principle for the protective role of the immune response against malignancy was established by the observation that tumors transplanted into syngeneic hosts were rejected by the host innate and adaptive responses. The impact of these therapeutic vaccination has taken a considerable time to become established - in part because target antigens against which an adaptive response can be directed do not appear to be uniquely expressed on malignant transformed cells; and also because tumor cells are able to manipulate their environment to downregulate the host immune response. Therapeutic cancer vaccines are also divided into active and passive types - the latter being subdivided into specific and non-specific vaccines. Active immunization utilizes an immunogen to generate a host response designed to eliminate the malignant cells, whereas in passive immunization preformed antibodies or cells are administered to directly eliminate the transformed cells - examples of each are considered in this review.

Biology and potential clinical implications of tissue inhibitor of metalloproteinases-1 in colorectal cancer treatment

Colorectal cancer (CRC) is the second leading cause of cancer-related death in the industrialized world. About half of "curatively" resected patients develop recurrent disease within the next 3-5 years despite the lack of clinical, histological and biochemical evidence of remaining overt disease after resection of the primary tumour. Availability of validated biological markers for early detection, selection for adjuvant therapy, prediction of treatment efficacy and monitoring of treatment efficacy would most probably increase survival. Tissue inhibitor of metalloproteinases-1 (TIMP-1) may be such a marker. TIMP-1 inhibits the proteolytic activity of metalloproteinases, which are centrally involved in tumour invasion and metastases. However, in clinical investigations high tumour tissue or plasma levels of TIMP-1 have shown a strong and independent association with a shorter survival time in CRC patients, suggesting that TIMP-1 could have a tumour-promoting function. Furthermore, measurement of plasma TIMP-1 has been shown to be useful for disease detection, with a high sensitivity and high specificity for early-stage colon cancer. This review describes some basic information on the current knowledge of the biology of TIMP-1 as well as the potential use of TIMP-1 as a biological marker in the management of CRC patients.

The biological effects of syngeneic and allogeneic cytokine-expressing prophylactic whole cell vaccines and the influence of irradiation in a murine melanoma model

Allogeneic whole tumour cell vaccines are inherently practical compared with autologous vaccines. Cell lines are derived from allogeneic tumour, grown in bulk and then administered as a vaccine to the patient, following irradiation, which not only prevents any replication but also enhances antigen presentation. Protection is believed to occur through the presentation of antigens shared between the syngeneic and allogeneic tumours. Although cytokine-transfected tumour whole cell vaccines have been used clinically, little data is available comparing the effects of immunomodulatory cytokine-transfection directly on the same cells when used as both an allogeneic and autologous vaccine. To address this, weakly immunogenic B16-F10 (H-2b) murine melanoma was transfected to secrete either GM-CSF, IL-4 or IL-7. Prophylactic vaccination of both syngeneic C57/BL6 (H-2b) (B6) and allogeneic C3H/Hej (H-2k) (C3H) mice showed the effects of transfected cytokine varied between models. Both GM-CSF and IL-7 significantly (P<0.05) increased the levels of protection within syngeneic B6 mice, but had a diminished effect (P>0.05) within C3H allogeneic mice. Allogeneic B16-F10 cells and syngeneic K1735 cells generated CTL against K1735 suggesting cross-reactive immunity. Using cells labeled with fluorescent dye we demonstrate that irradiated vaccines, of either syngeneic or allogeneic origin, appear to generate potent immune responses and fragments of either vaccine remain at the injection site for up to 9 days. This study shows that protection can be enhanced in vivo by using transfected cytokine, but suggests that irradiated whole cell vaccines, of either tissue-type, are rapidly processed. This leads to the conclusion that the cytokine effects are transient and thus transfection with cytokine may be of limited long-term use in situ.

Doxorubicin and paclitaxel enhance the antitumor efficacy of vaccines directed against HER 2/neu in a murine mammary carcinoma model

Introduction

The purpose of the present study was to determine whether cytotoxic chemotherapeutic agents administered prior to immunotherapy with gene vaccines could augment the efficacy of the vaccines.

Methods

Mice were injected in the mammary fat pad with an aggressive breast tumor cell line that expresses HER2/neu. The mice were treated 3 days later with a noncurative dose of either doxorubicin or paclitaxel, and the following day with a gene vaccine to HER2/neu. Two more doses of vaccine were given 14 days apart. Two types of gene vaccines were tested: a plasmid vaccine encoding a self-replicating RNA (replicon) of Sindbis virus (SINCP), in which the viral structural proteins were replaced by the gene for neu; and a viral replicon particle derived from an attenuated strain of Venezuelan equine encephalitis virus, containing a replicon RNA in which the Venezuelan equine encephalitis virus structural proteins were replaced by the gene for neu.

Results

Neither vaccination alone nor chemotherapy alone significantly reduced the growth of the mammary carcinoma. In contrast, chemotherapy followed by vaccination reduced tumor growth by a small, but significant amount. Antigen-specific CD8⁺ T lymphocytes were induced by the combined treatment, indicating that the control of tumor growth was most probably due to an immunological mechanism. The results demonstrated that doxorubicin and paclitaxel, commonly used chemotherapeutic agents for the treatment of breast cancer, when used at immunomodulating doses augmented the antitumor efficacy of gene vaccines directed against HER2/neu.

Conclusions

The combination of chemotherapeutic agents plus vaccine immunotherapy may induce a tumor-specific immune response that could be beneficial for the adjuvant treatment of patients with minimal residual disease. The regimen warrants further evaluation in a clinical setting.

Immune-Enhancing Effect of the Korean Natural Medicine WooKiEum

WooKiEum (WKE) has been used for the purpose of the development of increased immune-system strength in Korea. In the present study, we examined the anti-immobility effect of WKE on the forced swimming test (FST), and then measured blood biochemical parameters related to fatigue: glucose (Glc), blood urea nitrogen (BUN), lactic dehydrogenase (LDH), creatinine, and total protein (TP). WKE (0.1, 1 g/kg) was administered orally to mice for 7 d. After 2 d, the immobility time was decreased in the WKE-administered group. After 7 d, the immobility time was significantly decreased in the WKE-administered group (64.6+/-9.0 s for 0.1 g/kg) in comparison with the control group (101.3+/-32.7 s). In addition, amount of Glc in the blood serum was increased, whereas the contents of BUN, LDH and TP decreased in the WKE-administered group. Next, we investigated the effect of WKE on the production of cytokines in a human T-cell line, MOLT-4 cells and mouse peritoneal macrophages. WKE (1 mg/ml) significantly increased interferon (IFN)-gamma and TNF-alpha production compared with the media control (about 2.2-fold for IFN-gamma, about 1.7-fold for TNF-alpha, p<0.05) after 24 h. WKE increased the protein expression of IFN-gamma in MOLT-4 cells. These results suggest that WKE may be useful in immune function improvement.

The Immune-Enhancing Effect of the Herbal Combination Bouum-Myunyuk-Dan

The herbal formulation Bouum-Myunyuk-Dan (BMD) has long been used for various diseases. It has been shown to have antimicrobial and anti viral activity clinically. However, it is still unclear how BMD exerts these effects in experimental models. In this study, we investigated the effect of BMD on the production of cytokines in a human T cell line, MOLT-4 cells, and in mouse peritoneal macrophages. As a result, BMD significantly increased the viability and proliferation of splenocytes (p<0.05) and also significantly increased interleukin (IL)-2 and IL-4 production compared with media control (about 2.7-fold for IL-2 and 6.7-fold for IL-4, p<0.05) after 24 h. BMD increased the interferon (IFN)-gamma production by 3.7-fold but there were no significant differences compared with controls. Maximal effective concentrations of BMD were 1 mg/ml for IL-2 and IL-4 and 0.1 mg/ml for IFN-gamma. In addition, BMD (0.01 mg/ml) increased the production of tumor necrosis factor (TNF)-alpha and IL-12 in mouse peritoneal macrophages (by 2.7-fold for TNF-alpha and 42.5-fold for IL-12, p<0.05). In conclusion, these data indicate that BMD may have an immune-enhancing effect through the production of various cytokines.

Protective antitumor immunity induced by a costimulatory thalidomide analog in conjunction with whole tumor cell vaccination is mediated by increased Th1-type immunity

Thalidomide and its novel T cell costimulatory analogs (immunomodulatory drugs) are currently being assessed in the treatment of patients with advanced cancer. However, neither tumor-specific T cell costimulation nor effective antitumor activity has been demonstrated in vivo. In this study, we assessed the ability of an immunomodulatory drug (CC-4047/ACTIMID) to prime a tumor-specific immune response following tumor cell vaccination. We found that the presence of CC-4047 during the priming phase strongly enhanced antitumor immunity in the vaccinated group, and this correlated with protection from subsequent live tumor challenge. Protection was associated with tumor-specific production of IFN-gamma and was still observed following a second challenge with live tumor cells 60 days later. Furthermore, CD8(+) and CD4(+) splenocyte fractions from treated groups secreted increased IFN-gamma and IL-2 in response to tumor cells in vitro. Coculture of naive splenocytes with anti-CD3 mAb in the presence of CC-4047 directly costimulated T cells and increased Th1-type cytokines. Our results are the first to demonstrate that a costimulatory thalidomide analog can prime protective, long-lasting, tumor-specific, Th1-type responses in vivo and further support their ongoing clinical development as novel anti-cancer agents.