Potent effector function of tumor-sensitized L-selectin(low) T cells against subcutaneous tumors requires LFA-1 co-stimulation

Novel strategies for cancer immunotherapy: counter-immunoediting therapy

The advent of immunotherapy has made an indelible mark on the field of cancer therapy, especially the application of immune checkpoint inhibitors in clinical practice. Although immunotherapy has proven its efficacy and safety in some tumors, many patients still have innate or acquired resistance to immunotherapy. The emergence of this phenomenon is closely related to the highly heterogeneous immune microenvironment formed by tumor cells after undergoing cancer immunoediting. The process of cancer immunoediting refers to the cooperative interaction between tumor cells and the immune system that involves three phases: elimination, equilibrium, and escape. During these phases, conflicting interactions between the immune system and tumor cells result in the formation of a complex immune microenvironment, which contributes to the acquisition of different levels of immunotherapy resistance in tumor cells. In this review, we summarize the characteristics of different phases of cancer immunoediting and the corresponding therapeutic tools, and we propose normalized therapeutic strategies based on immunophenotyping. The process of cancer immunoediting is retrograded through targeted interventions in different phases of cancer immunoediting, making immunotherapy in the context of precision therapy the most promising therapy to cure cancer.

Flotillin-1 is a prognostic biomarker for glioblastoma and promotes cancer development through enhancing invasion and altering tumour microenvironment

Flotillin-1(FLOT1) has long been recognized as a tumour-promoting gene in several types of cancer. However, the expression and function of FLOT1 in glioblastomas (GBM) has not been elucidated. Here, in this study, we find that the expression level of FLOT1 in GBM tissue was much higher than that in normal brain, and the expression was even higher in the more aggressive subtypes and IDH status of glioma. Kaplan-Meier survival revealed that high FLOT1 expression is closely associated with poor outcome in GBM patients. FLOT1 knockdown markedly reduced the proliferation, migration and invasiveness of GBM cells, while FLOT1 overexpression significantly increases GBM cell proliferation, migration and invasiveness. Mechanistically, FLOT1 expression may play a potential role in the microenvironment of GBM. Therefore, FLOT1 promotes GBM proliferation and invasion in vitro and in vivo and may serve as a biomarker of prognosis and therapeutic potential in the fight against GBM.

Memory CD8+ T cell responses to cancer

Long-lived memory CD8⁺ T cells play important roles in tumor immunity. Studies over the past two decades have identified four subsets of memory CD8⁺ T cells - central, effector, stem-like, and tissue resident memory - that either circulate through blood, lymphoid and peripheral organs, or reside in tissues where cancers develop. In this article, we will review studies from both pre-clinical mouse models and human patients to summarize the phenotype, distribution and unique features of each memory subset, and highlight specific roles of each subset in anti-tumor immunity. Moreover, we will discuss how stem-cell like and resident memory CD8⁺ T cell subsets relate to exhausted tumor-infiltrating lymphocytes (TIL) populations. These studies reveal how memory CD8⁺ T cell subsets together orchestrate durable immunity to cancer.

Memory T cells in cancer immunotherapy: which CD8 T-cell population provides the best protection against tumours?

Cancer immunotherapy strategies often fail because of immunosuppressive mechanisms present in the tumour-bearing host. Adoptive T-cell transfer therapy circumvents this problem by activating tumour-specific CD8(+) T cells in vitro and transferring them back into the patient. Classically, effector T cells have been used in these studies because of their potent anti-tumour activity. However, it is becoming apparent that highly activated effector cells may become terminally differentiated, display impaired proliferation and survival in vivo, and mediate short-term anti-tumour effects. In contrast to effector cells, memory cells have enhanced proliferative potential and survival, and the potential to provide more robust and enduring protection against tumours. Here, we discuss key studies in the field of adoptive T-cell transfer, along with some of our own results relating to this area. Based on the body of existing research, it is clear that CD8(+) T cells with memory potential are superior to terminally differentiated effectors in mediating successful tumour clearance. Opinions remain divided as to whether the central memory or effector memory T-cell subset is capable of providing the best protection against tumours. We propose that as these cell types have different but complementary benefits for the anti-tumour immune response, the ideal cell population to use for adoptive T-cell transfer should consist of a heterogeneous mixture of memory cells.

Adoptive immunotherapy of cancer with polyclonal, 108-fold hyperexpanded, CD4+ and CD8+ T cells

T cell-mediated cancer immunotherapy is dose dependent and optimally requires participation of antigen-specific CD4+ and CD8+ T cells. Here, we isolated tumor-sensitized T cells and activated them in vitro using conditions that led to greater than 108-fold numerical hyperexpansion of either the CD4+ or CD8+ subset while retaining their capacity for in vivo therapeutic efficacy. Murine tumor-draining lymph node (TDLN) cells were segregated to purify the CD62Llow subset, or the CD4+ subset thereof. Cells were then propagated through multiple cycles of anti-CD3 activation with IL-2 + IL-7 for the CD8+ subset, or IL-7 + IL-23 for the CD4+ subset. A broad repertoire of TCR Vbeta families was maintained throughout hyperexpansion, which was similar to the starting population. Adoptive transfer of hyper-expanded CD8+ T cells eliminated established pulmonary metastases, in an immunologically specific fashion without the requirement for adjunct IL-2. Hyper-expanded CD4+ T cells cured established tumors in intracranial or subcutaneous sites that were not susceptible to CD8+ T cells alone. Because accessibility and antigen presentation within metastases varies according to anatomic site, maintenance of a broad repertoire of both CD4+ and CD8+ T effector cells will augment the overall systemic efficacy of adoptive immunotherapy.

Adoptive immunotherapy for malignant glioma

Despite remarkable advancements in imaging modalities and treatment options available to patients diagnosed with malignant brain tumors, the prognosis for those with high-grade lesions remains poor. The imprecise mechanisms of currently available treatments to manage these tumors do not spare damage to the normal surrounding brain and often result in major cognitive and motor deficits. Immunotherapy holds the promise of offering a potent, yet targeted, treatment to patients with brain tumors, with the potential to eradicate the malignant tumor cells without damaging normal tissues. The T cells of the immune system are uniquely capable of recognizing the altered protein expression patterns within tumor cells and mediating their destruction through a variety of effector mechanisms. Adoptive T-cell therapy is an attempt to harness and amplify the tumor-eradicating capacity of a patients' own T cells and then return these effectors to the patient in such a state that they effectively eliminate residual tumor. Although this approach is not new to the field of tumor immunology, new advancements in our understanding of T-cell activation and function and breakthroughs in tumor antigen discovery hold great promise for the translation of this modality into a clinical success.

Current status of adoptive immunotherapy of malignancies

Adoptive immunotherapy involves the transfer of immune effectors with antitumour activity into the tumour bearing host. Early approaches such as lymphokine activator killer (LAK) cells and tumour infiltrating lymphocytes (TILs) have yielded occasional clinical responses. More recently, attempts to stimulate and/or select antigen-specific T-cells in vitro have demonstrated that tumour-specific adoptive immunotherapy is possible. These approaches require complicated and time consuming in vitro stimulation procedures. Therefore, genetic modification of bulk T-cell populations is an attempt to create a large population of T-cells with a single specificity. In addition to work being done to develop the most potent effector, other studies are working on improving T-cell trafficking to tumours and interfering with the tumour-induced immunosuppression that can impair in vivo T-cell activity.