Cancer immunotherapy: Re-programming cells of the innate and adaptive immune systems

Boron Derivatives Inhibit the Proliferation of Breast Cancer Cells and Affect Tumor-Specific T Cell Activity In Vitro by Distinct Mechanisms

Breast cancer is the most frequently diagnosed cancer among women worldwide. Despite the initial clinical response obtained with the widely used conventional chemotherapy, an improved prognosis for breast cancer patients has been missing in the clinic because of the high toxicity to normal cells, induction of drug resistance, and the potential immunosuppressive effects of these agents. Therefore, we aimed to investigate the potential anti-carcinogenic effect of some boron derivatives (sodium pentaborate pentahydrate (SPP) and sodium perborate tetrahydrate (SPT)), which showed a promising effect on some types of cancers in the literature, on breast cancer cell lines, as well as immuno-oncological side effects on tumor-specific T cell activity. These findings suggest that both SPP and SPT suppressed proliferation and induced apoptosis in MCF7 and MDA-MB-231 cancer cell lines through downregulation of the monopolar spindle-one-binder (MOB1) protein. On the other hand, these molecules increased the expression of PD-L1 protein through their effect on the phosphorylation level of Yes-associated protein (Phospho-YAP (Ser127). In addition, they reduced the concentrations of pro-inflammatory cytokines such as IFN-γ and cytolytic effector cytokines such as sFasL, perforin, granzyme A, Granzyme B, and granulysin and increased the expression of PD-1 surface protein in activated T cells. In conclusion, SPP, SPT, and their combination could have growth inhibitory (antiproliferative) effects and could be a potential treatment for breast cancer. However, their stimulatory effects on the PD-1/PD-L1 signaling pathway and their effects on cytokines could ultimately account for the observed repression of the charging of specifically activated effector T cells against breast cancer cells.

Engineered extracellular vesicles and their mimetics for cancer immunotherapy

Extracellular vesicles (EVs) are heterogeneous membranous vesicles secreted by living cells that are involved in many physiological and pathological processes as intermediaries for intercellular communication and molecular transfer. Recent studies have shown that EVs can regulate the occurrence and development of tumors by transferring proteins, lipids and nucleic acids to immune cells as signaling molecules. As a new diagnostic biomarker and drug delivery system, EVs have broad application prospects in immunotherapy. In addition, the breakthrough of nanotechnology has promoted the development and exploration of engineered EVs for immune-targeted therapy. Herein, we review the uniqueness of EVs in immune regulation and the engineering strategies used for immunotherapy and highlight the logic of their design through typical examples. The present situation and challenges of clinical transformation are discussed, and the development prospects of EVs in immunotherapy are proposed. The goal of this review is to provide new insights into the design of immune-regulatory EVs and expand their application in cancer immunotherapy.

The association between CD28 gene rs3116496 polymorphism and breast cancer risk in Chinese women

T-lymphocyte activation plays an important role in suppressing the development of human cancers including breast cancer (BC). Cluster of differentiation 28 (CD28) is the primary T-cell costimulatory molecule and enhances T-cell activation and proliferation. To examine the role of CD28 gene polymorphism in BC, we conducted a case–control study involving 312 BC patients and 312 controls in a Chinese Han population. Bioinformatics analyses were conducted to analyze the expression level of CD28 and its association with overall survival (OS) of BC. Genotyping was performed using a custom-by-design 48-Plex single nucleotide polymorphism (SNP) Scan™ Kit. Our results indicated that CD28 mRNA level was down-regulated in the BC patients, whereas high expression of CD28 showed better OS for BC. In addition, an increased risk of BC was associated with the rs3116496 CC genotype of CD28 gene (CC vs. TT). The significant association was also observed in the recessive model. In conclusion, CD28 may be a tumor suppressor gene and rs3116496 polymorphism of CD28 gene showed positively correlation with the increased risk of BC. However, larger studies with more diverse ethnic populations are needed to confirm these results.

A brief review of clinical trials involving manipulation of invariant NKT cells as a promising approach in future cancer therapies

In the recent years researchers have put a lot of emphasis on the possible immunotherapeutic strategies able to target tumors. Many studies have proven that the key role in recognition and eradication of cancer cells, both for mice and humans, is being conducted by the invariant natural killer T-cells (NKT). This small subpopulation of lymphocytes can kill other cells, either directly or indirectly, through the natural killer cells’ (NK) activation. They can also swiftly release cytokines, causing the involvement of elements of the innate and acquired immune system. With the discovery of α-galactosylceramide (α-GalCer) – the first known agonist for iNKT cells – and its later subsequent analogs, it became possible to effectively stimulate iNKT cells, hence to keep control over the tumor progression. This article refers to the current knowledge concerning iNKT cells and the most important aspects of their antitumor activity. It also highlights the clinical trials that aim at increasing the amount of iNKT cells in general and in the microenvironment of the tumor. For sure, the iNKT-based immunotherapeutic approach holds a great potential and is highly probable to become a part of the cancer immunotherapy in the future.

HLA-DR expression on myeloid cells is a potential prognostic factor in patients with high-risk neuroblastoma

The adaptive immune system has been reported to play a dual role in many cancers, on one hand inhibiting tumor growth and, on the other hand, promoting disease progression, escape from cancer immunosurveillance and relapse. We have previously reported that the suppression of the adaptive immune response associated with high levels of myeloid-derived suppressor cells (MDSC) was evident in patients with low-risk neuroblastoma. Here, we report the results of a pilot study demonstrating that the amounts of HLA-DR-positive or negative myeloid cells in the peripheral blood might predict disease outcome among individuals affected by high-risk neuroblastoma.

Inflammation in the context of oral cancer

The link between cancer and inflammation is specific transcription factors that once activated have the capacity to enhance expression of genes that are common to both the regulation and the production of mediators of inflammation, and also to the regulation of the survival and proliferation of cancer cells. Cellular pathways activated by chronic inflammation brought about by chronic infections, by immune-mediated diseases, or by dysregulated wound healing at sites of repetitive tissue injury, constitute risk factors for initial cell transformation and for cancer progression. In established cancers, the cancer cells induce development of an exaggerated inflammatory state in the stroma, which in turn promotes cancer growth, invasion and metastasis. Inflammatory cells of myeloid origin in the tumour-associated stroma, mediate suppression of immune responses against cancer cells, which suppression favours tumour growth. Oral submucous fibrosis, and to a lesser extent oral lichen planus are precancerous conditions in which immuno-inflammatory processes are implicated in their pathogenesis, and in their cancerous transformation, if it occurs. Although there is some evidence for an association between oral squamous cell carcinoma on the one hand and dento-gingival bacterial plaques and chronic periodontitis on the other hand, the role of inflammation as the sole cause of cancerous transformation in such cases is not proven. The purpose of this article is to elaborate on some of the more important relationships between oral cancer and inflammation, and to comment on the role of inflammation in the pathogenesis of oral squamous cell carcinoma.

Can pharmacological receptor tyrosine kinase inhibitors sensitize poor outcome breast tumors to immune-based therapies?

Receptor tyrosine kinases (RTKs) drive breast cancer progression, particularly in human epidermal growth factor receptor 2 and basal tumors, the two worst prognosis subtypes. Tumor cells recruit host stromal components, including immune cells, which strongly influence disease progression. This has been studied in human breast cancer and translated to murine models of breast cancer. Stromal immune components including cytotoxic T lymphocytes (CTLs) and natural killer cells, destroy cancer cells through a process termed immune surveillance. Unfortunately, clinically detectable tumors escape these immune protective effects through their ability to limit the infiltration, activation, and/or survival of CTLs in breast tumors. The immunosuppressed state of established tumors limits the success rate of immune-based therapies, and possibly other therapeutic modalities that depend on host immunity. Published studies demonstrate that RTKs facilitate breast cancer progression, in part, by establishing immune suppression. This raises the intriguing possibility that pharmacological RTK inhibitors may be exploited to sensitize breast cancer patients to immune-based therapies.

T cell coinhibition and immunotherapy in human breast cancer

Costimulation and coinhibition generated by the B7 family and their receptor CD28 family have key roles in regulating T lymphocyte activation and tolerance. These pathways are very attractive therapeutic targets for human cancers including breast cancer. Gene polymorphisms of B7x (B7-H4/B7S1), PD-1 (CD279), and CTLA-4 (CD152) are associated with increased risk of developing breast cancer although the underlying mechanisms are unclear. In human breast cancer microenvironment, up-regulation of coinhibitory B7/CD28 members B7x, B7-H3 (CD276), and PD-L1 (B7-H1/CD274) on tumor cells as well as PD-1 and PD-L1 on tumor-infiltrating immune cells are emerging as immune evasion pathways. Chemotherapy can affect the expression of these molecules, and therefore may dampen the immune response against breast cancer. Immunotherapy targeting T cell coinhibition as monotherapy or combined with standard therapies are in early stages of clinical development, but hold great promise for treatment of human breast cancer.