The rat ErbB2 tyrosine kinase receptor produced in plants is immunogenic in mice and confers protective immunity against ErbB2(+) mammary cancer

Proteomics analysis of carcinogenesis in a rat model of mammary cancer induced by DMBA (7,12-dimethylbenz[a]anthracene)

Background: Mammary cancer, called breast cancer in humans, results from the abnormal growth of cells in the mammary glands that attack the surrounding tissue. The process of carcinogenesis at the molecular level can be monitored through the production of proteins as biomarkers for carcinogenesis. 7,12-Dimethylbenz[a]anthracene (DMBA) is a known carcinogenic compound. This study aimed to analyze the proteomic profile as critical data regarding DMBA-induced carcinogenesis in Sprague‒Dawley rats. Methods: Experimental animals were divided into two groups: a treatment group given DMBA at a dose of 10 mg/kg (intramammary) at intervals of 48 hours for a total of 10 doses, and a negative control group that was not given any treatment. Measurement of the total protein concentration was carried out using a spectrophotometer, and the data were analyzed using a t-test, while the characterization of protein profiles was carried out based on molecular weight data using SDS‒PAGE. Mammary gland histopathology was evaluated by hematoxylin and eosin (H&E) staining. Results: The results showed a significant (p<0.05) increase of 27% in the total protein concentration in the rat mammary cancer model. The results of proteomic characterization showed a protein profile containing proteins of 187, 169, 68, 64, 53, 41, 24, 18, and 14 kDa, which were suspected to be HER-2, Nischarin, COX-2, Albumine, Vimentin, ACTB, TNF, p16, and fatty acid binding protein 3 (FABP3), respectively. Histopathology of the mammary glands showed an irregular and indistinct arrangement of the alveoli and extensive epithelial cell proliferation from the surface to the lumen of the mammary ducts, and the mammary stroma showed the formation of new epithelial cells, which were cancer cells that spread to surrounding tissue. Conclusions: The proteomic profile was strongly associated with morphological alterations in mammary carcinogenesis in a rat model of DMBA-induced mammary cancer.

Exploring the Potential of Plant-Based Nanotechnology in Cancer Immunotherapy: Benefits, Limitations, and Future Perspectives

Reconceptualizing cancer immunotherapy can be improved if combined with plant production systems and nanotechnology. This review aims to contribute to the knowledge of plant use in nanomedicine and cancer immunotherapy. In the foreground, we outlined each of these approaches; nanomedicine, green synthesis, and immunotherapy. The benefits of plant-based nanoparticles in mending the immune systems were subsequently analyzed, with reference to the literature. The combining effects of biological and therapeutic properties of some phytochemicals and their derivatives, with targeted nanoparticles and selective immunotherapy, can enhance the delivery of drugs and antibodies, and induce antitumor immune responses, via activation of functions of neutrophils, lymphocyte cells, and natural killer cells, and macrophages, resulting in induced apoptosis and phagocytosis of tumor cells, which can improve designing immunotherapeutic strategies targeting cancer, with a larger spectrum compared to the current cytotoxic anticancer drugs commonly used in clinics. This study uncovers the mechanistic drivers of cancer immunoengineering in cancer therapy using plant-based nanomaterials, enhancing therapeutic benefits while minimizing toxic and side effects.

Plant-based vaccines and cancer therapy: Where are we now and where are we going?

Therapeutic vaccines are an effective approach in cancer therapy for treating the disease at later stages. The Food and Drug Administration (FDA) recently approved the first therapeutic cancer vaccine, and further studies are ongoing in clinical trials. These are expected to result in the future development of vaccines with relatively improved efficacy. Several vaccination approaches are being studied in pre-clinical and clinical trials, including the generation of anti-cancer vaccines by plant expression systems.This approach has advantages, such as high safety and low costs, especially for the synthesis of recombinant proteins. Nevertheless, the development of anti-cancer vaccines in plants is faced with some technical obstacles.Herein, we summarize some vaccines that have been used in cancer therapy, with an emphasis on plant-based vaccines.

Expression and immunogenicity assessment of a plant-made immunogen targeting the cytotoxic T-lymphocyte associated antigen-4: a possible approach for cancer immunotherapy

Cancer immunotherapy is a promising intervention to fight against this global health problem. In particular targeting immune checkpoints, such as cytotoxic T-lymphocyte associated antigen-4 (CTLA-4) and programmed-death protein 1 (PD-1), by specific monoclonal antibodies is a current treatment for many malignances. A possible innovation in this field is based on the induction of humoral responses in the host by suppressing the effects of such immune checkpoints and as consequence favoring the activation of cellular immunity against the tumor cells. In this study, chimeric protein comprising the B subunit of Escherichia coli heat-labile enterotoxin as carrier and the extracellular domain of CTLA-4 (LTB-CTLA4) was produced in Nicotiana benthamiana by transient expression. The recombinant protein was accumulated up to 1.29 μg/g of leaves fresh weight on 4 day-post-infiltration. The integrity of the plant-made LTB-CTLA4 antigen was confirmed by western blot analysis and ELISA. Immunogenicity of the plant-made LTB-CTLA4 was assessed in BALB/c mice and the results showed that humoral responses were induced against both the LTB and CTLA-4 moieties. The plant-made LTB-CTLA4 stands as a promising candidate for the design of advanced protection studies against cancer in murine models.

Metabolism and immunity in breast cancer

Breast cancer is one of the most common malignancies that seriously threaten women's health. In the process of the malignant transformation of breast cancer, metabolic reprogramming and immune evasion represent the two main fascinating characteristics of cancer and facilitate cancer cell proliferation. Breast cancer cells generate energy through increased glucose metabolism. Lipid metabolism contributes to biological signal pathways and forms cell membranes except energy generation. Amino acids act as basic protein units and metabolic regulators in supporting cell growth. For tumor-associated immunity, poor immunogenicity and heightened immunosuppression cause breast cancer cells to evade the host's immune system. For the past few years, the complex mechanisms of metabolic reprogramming and immune evasion are deeply investigated, and the genes involved in these processes are used as clinical therapeutic targets for breast cancer. Here, we review the recent findings related to abnormal metabolism and immune characteristics, regulatory mechanisms, their links, and relevant therapeutic strategies.

Plant Virus Expression Vectors: A Powerhouse for Global Health

Plant-made biopharmaceuticals have long been considered a promising technology for providing inexpensive and efficacious medicines for developing countries, as well as for combating pandemic infectious diseases and for use in personalized medicine. Plant virus expression vectors produce high levels of pharmaceutical proteins within a very short time period. Recently, plant viruses have been employed as nanoparticles for novel forms of cancer treatment. This review provides a glimpse into the development of plant virus expression systems both for pharmaceutical production as well as for immunotherapy.

Reconceptualizing cancer immunotherapy based on plant production systems

Plants can be used as inexpensive and facile production platforms for vaccines and other biopharmaceuticals. More recently, plant-based biologics have expanded to include cancer immunotherapy agents. The following review describes the current state of the art for plant-derived strategies to prevent or reduce cancers. The review discusses avenues taken to prevent infection by oncogenic viruses, solid tumors and lymphomas. Strategies including cancer vaccines, monoclonal antibodies and virus nanoparticles are described, and examples are provided. The review ends with a discussion of the implications of plant-based cancer immunotherapy for developing countries.

Cancer immunotherapy has made great strides over recent years. This review describes the use of plants as production systems to produce biopharmaceuticals such as vaccines and antibodies to treat a wide variety of cancers. The use of nanoparticle technology based on plant viruses as a novel strategy to target and combat cancers is also included. The review concludes with a discussion of plant production platforms and their relevance for the generation of cheap and effective cancer immunotherapies for developing countries.

A plant-expressed conjugate vaccine breaks CD4(+) tolerance and induces potent immunity against metastatic Her2(+) breast cancer

Passive antibody therapy for cancer is an effective but costly treatment modality. Induction of therapeutically potent anticancer antibodies by active vaccination is an attractive alternative but has proven challenging in cancer due to tolerogenic pressure in patients. Here, we used the clinically relevant cancer target Her2, known to be susceptible to targeting by antibody therapy, to demonstrate how potent antibody can be induced by vaccination. A novel 44kD Her2 protein fragment was generated and found to be highly effective at inducing anti-Her2 antibody including trastuzumab-like reactivities. In the tolerant and spontaneous BALB-neuT mouse model of metastatic breast cancer this Her2-targeting vaccine was only effective if the fragment was conjugated to a foreign immunogenic carrier; Fragment C of tetanus toxin. Only the conjugate vaccine induced high affinity anti-Her2 antibody of multiple isotypes and suppressed tumor development. The magnitude of CD4(+) T-cell help and breadth of cytokines secreted by the CD4(+) T helper (Th) cells induced to the foreign antigen was critical. We used a highly efficient plant-based bio-manufacturing process for protein antigens, magnICON, for vaccine expression, to underpin feasibility of future clinical testing. Hence, our novel Her2-targeting conjugate vaccine combines preclinical efficacy with clinical deliverability, thus setting the scene for therapeutic testing.

Enhanced GAD65 production in plants using the MagnICON transient expression system: Optimization of upstream production and downstream processing

Plants have emerged as competitive production platforms for pharmaceutical proteins that are required in large quantities. One example is the 65-kDa isoform of human glutamic acid decarboxylase (GAD65), a major autoimmune diabetes autoantigen that has been developed as a vaccine candidate for the primary prevention of diabetes. The expression of GAD65 in plants has been optimized but large-scale purification is hampered by its tendency to associate with membranes. We investigated the potential for large-scale downstream processing by evaluating different combinations of plant-based expression systems and engineered forms of GAD65 in terms of yield, subcellular localization and solubility in detergent-free buffer. We found that a modified version of GAD65 lacking the first 87 amino acids accumulates to high levels in the cytosol and can be extracted in detergent-free buffer. The highest yields of this variant protein were achieved using the MagnICON transient expression system. This combination of truncated GAD65 and the MagnICON system dramatically boosts the production of the recombinant protein and helps to optimize downstream processing for the establishment of a sustainable plant-based production platform for an autoimmune diabetes vaccine candidate.

Bovine herpesvirus 4-based vector delivering a hybrid rat/human HER-2 oncoantigen efficiently protects mice from autochthonous Her-2+ mammary cancer

The epidermal growth factor receptor 2 (HER-2) oncogene is a major target for the immunotherapy of breast cancer. Following up to the therapeutic success achieved with Her-2-targeting monoclonal antibodies, immune-prophylactic approaches directed against Her-2 have also been investigated taking into account, and trying to overcome, Her-2 self-tolerance. Perhaps due to safety (and efficacy) concerns, the least explored anti-Her-2 active immunization strategy so far has been the one relying on viral-vectored vaccine formulations. Taking advantage of the favorable properties of bovine herpesvirus 4 (BoHV-4) in terms of safety and ease of manipulation as well as its previously documented ability to transduce and confer immunogenicity to heterologous antigens, we tested the ability of different recombinant HER-2-BoHV-4 immunogens to 8break tolerance and elicit a protective, anti-mammary tumor antibody response in HER-2 transgenic BALB-neuT mice. All the tested constructs expressed the HER-2 transgenes at high levels and elicited significant cellular immune responses in BALB/c mice upon administration via either DNA vaccination or viral infection. In BALB-neuT mice, instead, only the viral construct expressing the membrane-bound chimeric form of Her-2 protein (BoHV-4-RHuT-gD) elicited a humoral immune response that was more intense and earlier-appearing than that induced by DNA vaccination. In keeping with this observation, two administrations of BoHV-4-RHuT-gD effectively protected BALB-neuT mice from tumor formation, with 50% of vaccinated animals tumor-free after 30 weeks from immunization compared to 100% of animals exhibiting at least one palpable tumor in the case of animals vaccinated with the other BoHV-4-HER-2 constructs.