Expression and roles of MICA in human osteosarcoma

Prospects for NK Cell Therapy of Sarcoma

Simple Summary

Sarcomas are a group of aggressive tumors originating from mesenchymal tissues. Patients with advanced disease have poor prognosis due to the ineffectiveness of current treatment protocols. A subset of lymphocytes called natural killer (NK) cells is capable of effective surveillance and clearance of sarcomas, constituting a promising tool for immunotherapeutic treatment. However, sarcomas can cause impairment in NK cell function, associated with enhanced tumor growth and dissemination. In this review, we discuss the molecular mechanisms of sarcoma-mediated suppression of NK cells and their implications for the design of novel NK cell-based immunotherapies against sarcoma.

Abstract

Natural killer (NK) cells are innate lymphoid cells with potent antitumor activity. One of the most NK cell cytotoxicity-sensitive tumor types is sarcoma, an aggressive mesenchyme-derived neoplasm. While a combination of radical surgery and radio- and chemotherapy can successfully control local disease, patients with advanced sarcomas remain refractory to current treatment regimens, calling for novel therapeutic strategies. There is accumulating evidence for NK cell-mediated immunosurveillance of sarcoma cells during all stages of the disease, highlighting the potential of using NK cells as a therapeutic tool. However, sarcomas display multiple immunoevasion mechanisms that can suppress NK cell function leading to an uncontrolled tumor outgrowth. Here, we review the current evidence for NK cells’ role in immune surveillance of sarcoma during disease initiation, promotion, progression, and metastasis, as well as the molecular mechanisms behind sarcoma-mediated NK cell suppression. Further, we apply this basic understanding of NK–sarcoma crosstalk in order to identify and summarize the most promising candidates for NK cell-based sarcoma immunotherapy.

Natural Killer Cell Immunotherapy for Osteosarcoma

Natural killer (NK) cells are lymphocytes of the innate immune system that have the ability to recognize malignant cells through balanced recognition of cell-surface indicators of stress and danger. Once activated through such recognition, NK cells release cytokines and induce target cell lysis through multiple mechanisms. NK cells are increasingly recognized for their role in controlling tumor progression and metastasis and as important mediators of immunotherapeutic modalities such as cytokines, antibodies, immunomodulating drugs, and stem cell transplantation. Recent advances in manipulating NK cell number, function, and genetic modification have caused renewed interest in their potential for adoptive immunotherapies, which are actively being tested in clinical trials. Here, we summarize the evidence for NK cell recognition of osteosarcoma, discuss immune therapies that are directly or indirectly dependent on NK cell function, and describe potential approaches for manipulating NK cell number and function to enhance therapy against osteosarcoma.

Effect of entinostat on NK cell-mediated cytotoxicity against osteosarcoma cells and osteosarcoma lung metastasis

There is a crucial need for a new therapeutic approach for osteosarcoma (OS) lung metastasis since this disease remains the main cause of mortality in OS. We previously demonstrated that natural killer (NK) cell therapy has minimal efficacy against OS metastasis. This study determined whether the histone deacetylase inhibitor entinostat could immunosensitize OS cells to NK cell lysis and increases the efficacy of NK cell therapy for OS lung metastasis. Entinostat upregulated ligands for NK cell-activating receptors (major histocompatibility complex [MHC] class I polypeptide-related chain A [MICA] and B [MICB]; UL16 binding proteins 1, 2, 5, and 6; and CD155) on OS cells both in vitro and in vivo and led to more susceptibility to NK cell-mediated cytotoxicity in vitro. Importantly, entinostat did not change NK cell viability, receptor expression, or function within the 24-h treatment. We also demonstrated two potential mechanisms by which entinostat enhanced expression of MICA and MICB on OS cells. Although entinostat upregulated ligands for the NK cell activating receptor on OS lung metastasis, it failed to augment the efficacy of NK cell therapy in our nude mouse human OS lung metastasis model. This can be partly explained by our finding that although the infused NK cells were active and functional and could penetrate into the lungs, they failed to infiltrate into the lung nodules. These challenges regarding cellular immunotherapy against solid tumors may be overcome by combination therapy, such as adding a NK cell-activating cytokine (IL-2 or IL-21).

The clinical and biological significance of MICA in clear cell renal cell carcinoma patients

Major histocompatibility complex class I-related chains A (MICA), a ligand of Natural killer group 2, member D (NKG2D) receptor, is broadly upregulated in epithelial originated tumor cells. MICA plays a critical role in the immune surveillance against tumor cells and is associated with the prognosis of several malignancies. The aim of this study is to evaluate the clinical and biological significance of MICA in clear cell renal cell carcinoma (ccRCC). The expression of MICA was analyzed by quantitative real-time PCR (qRT-PCR) and immunohistochemistry (IHC). Both MICA mRNA and protein levels were upregulated in ccRCC tissues, compared with normal tissues. IHC staining revealed a homogenous pattern of MICA staining within each tumor, which combined both membrane staining and granular cytoplasmic staining. Furthermore, high MICA expression was associated with lymph node metastasis and advanced clinical stage and predicted poor prognosis in patients with ccRCC. Gene set enrichment analysis (GSEA) was performed using RNA-sequencing data from The Cancer Genome Atlas Research Network (TCGA) to elucidate the biological role of MICA in ccRCC and revealed that MICA was significantly associated with the epithelial-to-mesenchymal transition (EMT) gene set, which was further confirmed by qRT-PCR. Our findings contribute to the studies on biomarkers of kidney cancers and the mechanism of renal cancer progression driven by EMT pathway.

Activated and expanded natural killer cells target osteosarcoma tumor initiating cells in an NKG2D-NKG2DL dependent manner

Current therapies fail to cure most metastatic or recurrent bone cancer. We explored the efficacy and the pathways involved in natural killer (NK) cells' elimination of osteosarcoma (OS) cells, including tumor initiating cells (TICs), which are responsible for chemotherapy resistance, recurrence, and metastasis. The expression of ligands for NK cell receptors was studied in primary OS cell lines by flow cytometry. In vitro cytotoxicity of activated and expanded NK (NKAE) cells against OS was tested, and the pathways involved explored by using specific antibody blockade. NKAE cells' ability to target OS TICs was analyzed by flow cytometry and sphere formation assays. Spironolactone (SPIR) was tested for its ability to increase OS cells' susceptibility to NK cell lysis in vitro and in vivo. We found OS cells were susceptible to NKAE cells' lysis both in vivo and in vitro, and this cytolytic activity relied on interaction between NKG2D receptor and NKG2D ligands (NKG2DL). SPIR increased OS cells' susceptibility to lysis by NKAE cells, and could shrink the OS TICs. Our results show NKAE cells target OS cells including the TICs compartment, supporting the use of NK-cell based immunotherapies for OS.

Effects of MICA expression on the prognosis of advanced non-small cell lung cancer and the efficacy of CIK therapy

Objective

To investigate the clinical significance of the expression of MHC class I chain-related gene A (MICA) in patients with advanced non-small cell lung cancer and explore the relationship between MICA expression and the efficacy of cytokine-induced killer cell (CIK) therapy for treating advanced non-small cell lung cancer.

Methods

We obtained data on 222 patients with advanced non-small cell lung cancer, including data on MICA expression, age, gender, ECOG score, pathological type, stage, treatment history (including 38 patients who were given autologous CIK cell infusion), and overall survival (OS). MICA expression in lung cancer tissue was evaluated by immunohistochemical staining. Analyses of MICA expression, and CIK therapy association with survival outcomes were performed using Cox proportional models, Kaplan-Meier methods, and the log-rank test.

Result

s MICA was expressed in both membrane and cytoplasm. MICA expression correlated with the stage of lung cancer, ECOG score, gender and age. Multivariate COX regression analysis showed that the expression of MICA was an independent prognostic factor of advanced non-small cell lung cancer (p = 0.002). In subgroup analysis, we divided the 222 patients into CIK and control groups. In the CIK group, the medium OS (mOS) of patients with a high expression of MICA was longer than in those with low expression of MICA (27 months vs. 13 months). In the control group, the mOS in patients with a high expression of MICA was shorter than in patients with low MICA expression (9 months vs. 18 months). COX regression analysis showed that the MICA expression affects the effect of CIK therapy (p<0.0001).

Conclusion

1) The high expression of MICA is one of the indicators of a poor prognosis for advanced non-small cell lung cancer patients. 2) The high expression of MICA might be one of the predictive factors for successful CIK therapy.

Retrospective study of spontaneous osteosarcomas in the nonobese diabetic strain and nonobese diabetic-derived substrains of mice

In this retrospective study, spontaneous osteosarcomas were found in 85 of 1,202 (7.1%) nonobese diabetic (NOD) and NOD-derived mice. Gross tumors were evident at an average age of 155.8 days in male mice and 151.4 days in female mice. Compared with male mice, female mice had a statistically insignificant higher incidence: 56 cases (8.3% of 672) versus 28 cases (6.1% of 458). NOD/ShiLtJ mice had the highest incidence, with 39 cases among all the strains and substrains represented (3.2% of 1,202 necropsies), whereas NOD.SCID substrains had the highest incidence, with 16 cases among the various NOD-derived substrains (1.3% of 1,202 necropsies). There was a statistically significant difference in tumor incidence between NOD/ShiLtJ and NOD.SCID mice. Tumors were more frequent in the appendicular skeleton (55.7%) than in the axial skeleton (44.3%) and most often arose from the femurs. Histologically, osteoblastic osteosarcoma was the most common tumor type, with 79 cases (94%), followed by mixed osteosarcoma, with 5 cases (6%). Metastases were rare, with only 2 cases (2.3%).