Targeting breast cancer vaccines to dendritic cells: improved immunological responses with less protein?

Intercepting Premalignant, Preinvasive Breast Lesions Through Vaccination

Breast cancer (BC) prevention remains the ultimate cost-effective method to reduce the global burden of invasive breast cancer (IBC). To date, surgery and chemoprevention remain the main risk-reducing modalities for those with hereditary cancer syndromes, as well as high-risk non-hereditary breast lesions such as ADH, ALH, or LCIS. Ductal carcinoma in situ (DCIS) is a preinvasive malignant lesion of the breast that closely mirrors IBC and, if left untreated, develops into IBC in up to 50% of lesions. Certain high-risk patients with DCIS may have a 25% risk of developing recurrent DCIS or IBC, even after surgical resection. The development of breast cancer elicits a strong immune response, which brings to prominence the numerous advantages associated with immune-based cancer prevention over drug-based chemoprevention, supported by the success of dendritic cell vaccines targeting HER2-expressing BC. Vaccination against BC to prevent or interrupt the process of BC development remains elusive but is a viable option. Vaccination to intercept preinvasive or premalignant breast conditions may be possible by interrupting the expression pattern of various oncodrivers. Growth factors may also function as potential immune targets to prevent breast cancer progression. Furthermore, neoantigens also serve as effective targets for interception by virtue of strong immunogenicity. It is noteworthy that the immune response also needs to be strong enough to result in target lesion elimination to avoid immunoediting as it may occur in IBC arising from DCIS. Overall, if the issue of vaccine targets can be solved by interrupting premalignant lesions, there is a potential to prevent the development of IBC.

Immunotherapy in breast cancer: Current status and future directions

Breast cancer, one of the leading causes of death in women in the United States, challenges therapeutic success in patients due to tumor heterogeneity, treatment resistance, metastasis and disease recurrence. Knowledge of immune system involvement in normal breast development and breast cancer has led to extensive research into the immune landscape of breast cancer and multiple immunotherapy clinical trials in breast cancer patients. However, poor immunogenicity and T-cell infiltration along with heightened immunosuppression in the tumor microenvironment have been identified as potential challenges to the success of immunotherapy in breast cancer. Oncodrivers, owing to their enhanced expression and stimulation of tumor cell proliferation and survival, present an excellent choice for targeted immunotherapy development in breast cancer. Loss of anti-tumor immune response specific to oncodrivers has been reported in breast cancer patients as well. Dendritic cell vaccines have been tested for their efficacy in generating anti-tumor T-cell response against specific tumor-associated antigens and oncodrivers and have shown improved survival outcome in patients. Here, we review the current status of immunotherapy in breast cancer, focusing on dendritic cell vaccines and their therapeutic application in breast cancer. We further discuss future directions of breast cancer immunotherapy and potential combination strategies involving dendritic cell vaccines and existing chemotherapeutics for improved efficacy and better survival outcome in breast cancer.

Pros and Cons of Antigen-Presenting Cell Targeted Tumor Vaccines

In therapeutic antitumor vaccination, dendritic cells play the leading role since they decide if, how, when, and where a potent antitumor immune response will take place. Since the disentanglement of the complexity and merit of different antigen-presenting cell subtypes, antitumor immunotherapeutic research started to investigate the potential benefit of targeting these subtypes in situ. This review will discuss which antigen-presenting cell subtypes are at play and how they have been targeted and finally question the true meaning of targeting antitumor-based vaccines.

Immune response, clinical outcome and safety of dendritic cell vaccine in combination with cytokine-induced killer cell therapy in cancer patients

The aim of the present study was to determine the clinical value of autologous immunocyte therapy as a standard treatment regimen for patients with cancer. A total of 121 patients with cancer were included in this study. Subsequent to performing leukapheresis using the Fresenius Kabi System, 1×10⁷ dendritic cells (DCs) for the vaccine and 1×10⁹ cytokine-induced killer (CIK) cells for injection were prepared. An analysis of the immune phenotypes of HLA2DR, CD80 and CD83 for the DCs and of CD3, CD8 and CD56 for the CIK cells, as well as negative detection of bacteria and endotoxin, were used as the quality standards. The delayed-type hyper-sensitivity (DTH) skin test was used to measure the immune response, while physical strength, appetite and sleeping status were analyzed for the clinical outcome. Fever, insomnia, anorexia, joint soreness and skin rashes were recorded as side-effects. Patients received the DC vaccination once a week for six weeks and a CIK cell injection six times within four days. In total, 121 cancer patients with primary tumors located in the colorectum (43.0%), lung (15.7%), breast (11.6%), kidney (5.8%), stomach (4.1%) and other regions (19.8%) were included in the study. A positive cell-mediated cytotoxicity response rate of 76.9% was detected by the DTH skin tests. Improvements in physical strength, appetite and sleeping status were observed in 94.1, 83.9 and 76.3% of cases, respectively. None of the serious adverse side-effects that commonly occur during chemotherapy and radiotherapy were observed. During therapy, 69 cases developed a fever that was resolved with antipyretics, dexamethasone or physical cooling, while 28 cases developed insomnia combined with excitement, 19 cases complained of anorexia, 11 cases complained of joint soreness, which was alleviated using analgesics, and 8 cases developed skin rashes. The combined use of CIK cells with a DC-based cancer vaccination strategy may be used to target innate and adaptive immune mechanisms and synergistically promote positive clinical outcomes. The therapy was safe and no serious adverse side-effects similar to those caused by chemotherapy and radiotherapy were observed. The regimen may have a beneficial effect in the future treatment of patients with cancer.