The future of immunotherapy for sarcoma

Digging Through the Complexities of Immunological Approaches in Emerging Osteosarcoma Therapeutics: A Comprehensive Narrative Review with Updated Clinical Trials

Osteosarcoma (OS) is the predominant mesenchymal primary malignant bone tumor in oncology and pathology, impacting a wide age range from adolescents to older adults. It frequently advances to lung metastasis, ultimately resulting in the mortality of OS patients. The precise pathological pathways responsible for OS progression and dissemination are not fully understood due to its heterogeneity. The integration of surgery with neoadjuvant and postoperative chemotherapy has significantly increased the 5-year survival rate to more than 70% for patients with localized OS tumors. However, about 30% of patients experience local recurrence and/or metastasis. Hence, there is a requirement for innovative therapeutic approaches to address the limitations of traditional treatments. Immunotherapy has garnered increasing attention as a promising avenue for tumors resistant to standard therapies, including OS, despite the underlying mechanisms of disease progression and dissemination remaining not well elucidated. Immunotherapy may not have been suitable for use in patients with OS because of the tumor's immunosuppressive microenvironment and limited immunogenicity. Nevertheless, there are immune-based treatments now being developed for clinical use, such as bispecific antibodies, chimeric antigen receptor T cells, and immune checkpoint inhibitors. Also, additional immunotherapy techniques including cytokines, vaccines, and modified-Natural Killer (NK) cells/macrophages are in the early phases of research but will certainly be popular subjects in the nearest future. Our goal in writing this review was to spark new lines of inquiry into OS immunotherapy by summarizing the findings from both preclinical and current clinical studies examining different approaches.

Managing the immune microenvironment of osteosarcoma: the outlook for osteosarcoma treatment

Osteosarcoma, with poor survival after metastasis, is considered the most common primary bone cancer in adolescents. Notwithstanding the efforts of researchers, its five-year survival rate has only shown limited improvement, suggesting that existing therapeutic strategies are insufficient to meet clinical needs. Notably, immunotherapy has shown certain advantages over traditional tumor treatments in inhibiting metastasis. Therefore, managing the immune microenvironment in osteosarcoma can provide novel and valuable insight into the multifaceted mechanisms underlying the heterogeneity and progression of the disease. Additionally, given the advances in nanomedicine, there exist many advanced nanoplatforms for enhanced osteosarcoma immunotherapy with satisfactory physiochemical characteristics. Here, we review the classification, characteristics, and functions of the key components of the immune microenvironment in osteosarcoma. This review also emphasizes the application, progress, and prospects of osteosarcoma immunotherapy and discusses several nanomedicine-based options to enhance the efficiency of osteosarcoma treatment. Furthermore, we examine the disadvantages of standard treatments and present future perspectives for osteosarcoma immunotherapy.

Heparin and Heparin-Based Drug Delivery Systems: Pleiotropic Molecular Effects at Multiple Drug Resistance of Osteosarcoma and Immune Cells

One of the main problems of modern health care is the growing number of oncological diseases both in the elderly and young population. Inadequately effective chemotherapy, which remains the main method of cancer control, is largely associated with the emergence of multidrug resistance in tumor cells. The search for new solutions to overcome the resistance of malignant cells to pharmacological agents is being actively pursued. Another serious problem is immunosuppression caused both by the tumor cells themselves and by antitumor drugs. Of great interest in this context is heparin, a biomolecule belonging to the class of glycosaminoglycans and possessing a broad spectrum of biological activity, including immunomodulatory and antitumor properties. In the context of the rapid development of the new field of “osteoimmunology,” which focuses on the collaboration of bone and immune cells, heparin and delivery systems based on it may be of intriguing importance for the oncotherapy of malignant bone tumors. Osteosarcoma is a rare but highly aggressive, chemoresistant malignant tumor that affects young adults and is characterized by constant recurrence and metastasis. This review describes the direct and immune-mediated regulatory effects of heparin and drug delivery systems based on it on the molecular mechanisms of (multiple) drug resistance in (onco) pathological conditions of bone tissue, especially osteosarcoma.

Novel Immunotherapies for Osteosarcoma

Osteosarcoma (OS) is the most common primary malignant bone sarcoma mainly affecting adolescents and young adults, which often progresses to pulmonary metastasis and leads to the death of OS patients. OS is characterized as a highly heterogeneous cancer type and the underlying pathologic mechanisms triggering tumor progress and metastasis are incompletely recognized. Surgery combined with neoadjuvant and postoperative chemotherapy has elevated 5-year survival to over 70% for patients with localized OS tumors, as opposed to only 20% of patients with recurrence and/or metastasis. Therefore, novel therapeutic strategies are needed to overcome the drawbacks of conventional treatments. Immunotherapy is gaining momentum for the treatment of OS with an increasing number of FDA-approved therapies for malignancies resistant to conventional therapies. Here, we review the OS tumor microenvironment and appraise the promising immunotherapies available in the management of OS.

Identification of Ferroptosis-Related Genes as Biomarkers for Sarcoma

Sarcomas are seen as mixed-up nature with genetic and transcriptional heterogeneity and poor prognosis. Although the genes involved in ferroptosis are still unclear, iron loss is considered to be the core of glioblastoma, tumor progression, and tumor microenvironment. Here, we developed and tested the prognosis of SARC, which is a genetic marker associated with iron residues. The ferroptosis-related gene expression, one-way Cox analysis, and least-selection absolute regression algorithm (LASSO) are used to track prognostic-related genes and create risk assessment models. Finally, immune system infiltration and immune control point analysis are used to study the characteristics of the tumor microenvironment related to risk assessment. Moreover, LncRNA–miRNA–mRNA network was contributed in our studies. We determined the biomarker characteristics associated with iron degradation in gene 32 and developed a risk assessment model. ROC analysis showed that its model was accurately predicted, with 1, 2, 3, 4, and 5 years of overall survival in TCGA cohort of SARC patients. A comparative analysis of settings found that overall survival (OS) was lower in the high-risk than that in the low-risk group. The nomogram survival prediction model also helped to predict the OS of SARC patients. The nomogram survival prediction model has strong predictive power for the overall survival of SARC patients in TCGA dataset. GSEA analysis shows that high-risk groups are rich in inflammation, cancer-related symptoms, and pathological processes. High risk is related to immune cell infiltration and immune checkpoint. Our prediction model is based on SARC ferritin-related genes, which may support SARC prediction and provide potential attack points.

Olaratumab's failure in soft tissue sarcoma

Soft tissue sarcomas remain one of the rarest malignancies with numerous subtypes that go undiagnosed. The PDGFRα antagonist Olaratumab (Lartruvo) was withdrawn from the market due to disappointing findings in the phase III studies. We share our experience with this medication in a tertiary care center in the Middle East and North Africa region. Monitor the effect of Olaratumab on sarcomas when it was used prior to its withdrawal, and compare our findings with the literature. We performed a retrospective analysis of adult patients with advanced-/metastatic soft tissue sarcomas treated with at least two cycles of Olaratumab at a tertiary care center in Lebanon during the period from January 1, 2017 to December 31, 2018. Fifteen patients were included in the study. The mean age was 49 with a range of 26–75 years. The median duration of the use of Olaratumab was 21.3 months with a range of 7.3–37 months. The average number of number of cycles received per patient was four. Five patients were deceased. Median PFS was 7.87 months (95% CI 5.28–10.45), and mean OS was 12.26 months (95% CI 8.47–16.05) Median OS was 9.8 months (95% CI 6.07–13.53). Olaratumab has been withdrawn from the market, and it is currently being investigated as part of the phase II ANNOUNCE 2 trial. Our experience from a tertiary care center shows results similar to those reported in the literature. The immunogenicity and heterogeneity of soft tissue sarcomas pose a challenge to the treatment of soft tissue sarcomas, but they also allow a wide array of possible management solutions.

Identification of prognostic biomarkers associated with metastasis and immune infiltration in osteosarcoma

Osteosarcoma is the most common primary malignancy of the bones, and is associated with a high rate of metastasis and a poor prognosis. A tight association between the tumor microenvironment (TME) and osteosarcoma metastasis has been established. In the present study, the Estimation of STromal and Immune cells in MAlignant Tumor tissues using Expression data (ESTIMATE) algorithm was applied to calculate the immune and stromal scores of patients with osteosarcoma based on data from The Cancer Genome Atlas database. A metagene approach and deconvolution method were used to reveal distinct TME landscapes in patients with osteosarcoma. Bioinformatics analysis was used to identify differentially expressed genes (DEGs) associated with metastasis and immune infiltration in osteosarcoma, and a risk model was constructed using the DEGs with potential prognostic significance. Subsequently, gene set enrichment and Spearman's correlation analyses were used to delineate the biological processes associated with these prognostic biomarkers. Finally, immunohistochemical (IHC) analysis was performed to evaluate the expression levels of immune infiltrates and prognostic biomarkers in clinical osteosarcoma tissues. The results of the ESTIMATE demonstrated that patients with non-metastatic osteosarcoma presented with higher immune/stromal scores and a more favorable prognosis compared with those with metastatic osteosarcoma. The TME landscapes in patients with osteosarcoma suggested that high levels of tumor-infiltrating immune cells (TIICs) may suppress metastasis. Increased numbers of CD56bright natural killer cells, immature B cells, M1 macrophages and neutrophils, and lower levels of M2 macrophages were observed in the non-metastatic tissues compared with those in the metastatic tissues. A total of 69 DEGs were identified to be associated with metastasis and immune infiltration in osteosarcoma. Of these, GATA3, LPAR5, EVI2B, RIAM and CFH exhibited prognostic potential and were highly expressed in non-metastatic osteosarcoma tissues based on the IHC analysis results. These biomarkers were involved in various immune-related biological processes and were positively associated with multiple TIICs and immune signatures. The risk model constructed using these prognostic biomarkers demonstrated high predictive accuracy for the prognosis of osteosarcoma. In conclusion, the present study proposed a five-biomarker prognostic signature for the prediction of metastasis and immune infiltration in patients with osteosarcoma.

Key Immune Checkpoint PD-1/PD-L1 Signaling Pathway Components in the Blood Serum from Patients with Bone Tumors

The levels of sPD-1 and sPD-L1 were analyzed in blood serum of 132 patients (age 14-70 years) with primary bone tumors: osteosarcoma (N=39), chondrosarcoma (N=42), Ewing sarcoma (N=9), chordoma (N=12), giant-cell bone tumor (GCBT) (N=16), benign neoplasms (N=14) and in and practically healthy subjects (age 19-58 years; N=27). sPD-L1 levels in all studied bone neoplasms were significantly higher than in the control. Serum sPD-1 level in GCBT patients was significantly higher than in the control, benign neoplasms, chondrosarcoma, and chordoma patients, but did not differ from osteosarcoma group. sPD-1 concentration in Ewing sarcoma was significantly higher than in chordoma and chondrosarcoma, but did not differ from the control. sPD-1 level in chondrosarcoma patients was also lower than in osteosarcoma, Ewing sarcoma, and in the control. Both sPD-1 and sPD-L1 concentrations were not significantly associated with the type of affected bone, process localization, disease stage, tumor histological grade, patients' age and sex. These results suggest the possibility of using these biological markers for preliminary assessment of the character of the process in the bone.

Water extract of sporoderm-broken spores of Ganoderma lucidum enhanced pd-l1 antibody efficiency through downregulation and relieved complications of pd-l1 monoclonal antibody

PURPOSE

Osteosarcoma is a malignant musculoskeletal tumor with early metastasis and a poor prognosis, especially in adolescents. Ganoderma lucidum (Leyss. Ex Fr.) Karst (G. lucidum), a traditional East Asian medicine, has been reported to play a critical role in antitumor and immunomodulatory activity. The aim of this study was to investigate the effects and molecular mechanisms of water extract of sporoderm-broken spores of G. lucidum (BSGWE) on osteosarcoma PD-L1 (programmed cell death-ligand 1) transcriptional regulation, efficacy enhancement, and side effect remission.

METHODS

The antitumor effects on cell proliferation of BSGWE in osteosarcoma cells were detected by apoptosis flow cytometry, and the migration ability of HOS and K7M2 cells were evaluated by cell scratch assay. Potential signaling regulation of PD-L1 was detected by western blotting. To confirm the signaling pathway of BSGWE-related PD-L1 downregulation, a pho-STAT3 turnover experiment was carried out. Colivelin was administered as a pho-STAT3 activator to rescue the BSGWE-induced PD-L1 inhibition. To further study in vivo signaling, in a Balb/c osteosarcoma allograft model, tumor volume was measured using an in vivo bioluminescence imaging system. The body weight curve and tumor volume curve were analyzed to reveal the remission effects of BSGWE on PD-L1 antibody-related body weight loss and its immunomodulatory effects on the osteosarcoma and spleen. The PD-L1 expression level and expression of related transcription-factor pho-STAT3 in tumor cells and spleens were assessed by IHC analysis.

RESULTS

BSGWE suppressed the proliferation and migration of osteosarcoma cells in vitro via induction of apoptosis. In addition, BSGWE downregulated PD-L1 expression and related STAT3 (signal transducers and activators of transcription) phosphorylation levels in a dose-dependent manner. Western blotting and qRT-PCR assay revealed that BSGWE downregulated PD-L1 expression by inhibiting STAT3 phosphorylation. A turnover experiment showed that colivelin administration could rescue PD-L1 inhibition via pho-STAT3 activation. BSGWE not only downregulated PD-L1 expression via the STAT3 pathway in an allograft Balb/c mouse model, but also relieved complications including weight loss and spleen atrophy in a mouse monoclonal antibody therapy model on the basis of its traditional advantages in immune enhancement.

CONCLUSION

BSGWE downregulated PD-L1 expression via pho-STAT3 inhibition of protein and RNA levels. BSGWE enhanced PD-L1 antibody efficacy via phosphorylated STAT3 downregulation in vitro and in vivo. BSGWE also relieved complications of weight loss and spleen atrophy in a murine allograft osteosarcoma immune checkpoint blockade therapy model.

Development of an artificial antibody specific for HLA/peptide complex derived from cancer stem-like cell/cancer-initiating cell antigen DNAJB8

Background

Peptide-vaccination therapy targeting tumour-associated antigens can elicit immune responses, but cannot be used to eliminate large tumour burden. In this study, we developed a therapeutic single-chain variable-fragment (scFv) antibody that recognises the cancer stem-like cell/cancer-initiating cell (CSC/CIC) antigen, DNAJB8.

Methods

We screened scFv clones reacting with HLA-A24:20/DNAJB8-derived peptide (DNAJB8_143) complex using naive scFv phage-display libraries. Reactivity and affinity of scFv clones against the cognate antigen were quantified using FACS and surface plasmon resonance. Candidate scFv clones were engineered to human IgG1 (hIgG1) and T-cell-engaging bispecific antibody (CD3xJB8). Complement-dependent cytotoxicity (CDC) and bispecific antibody-dependent cellular cytotoxicity (BADCC) were assessed.

Results

scFv clones A10 and B10 were isolated after bio-panning. Both A10-hIgG1 and B10-hIgG1 reacted with DNAJB8-143 peptide-pulsed antigen-presenting cells and HLA-A24(+)/DNAJB8(+) renal cell carcinoma and osteosarcoma cell lines. A10-hIgG1 and B10-hIgG1 showed strong affinity with the cognate HLA/peptide complex (K_D = 2.96 × 10⁻⁹ M and 5.04 × 10⁻⁹ M, respectively). A10-hIgG1 and B10-hIgG1 showed CDC against HLA-A24(+)/DNAJB8(+) cell lines. B10-(CD3xJB8) showed superior BADCC to A10-(CD3xJB8).

Conclusion

We isolated artificial scFv antibodies reactive to CSC/CIC antigen DNAJB8-derived peptide naturally present on renal cell carcinoma and sarcoma. Immunotherapy using these engineered antibodies could be promising.

Peptide vaccinations elicited strong immune responses that were reboosted by anti-PD1 therapy in a patient with myxofibrosarcoma

Peptide-based immunotherapy does not usually elicit strong immunological and clinical responses in patients with end-stage cancer, including sarcoma. Here we report a myxofibrosarcoma patient who showed a strong clinical response to peptide vaccinations and whose immune responses were reboosted by anti-PD1 therapy combined with peptide vaccinations. The 46-year-old man showed a strong response to the peptide vaccinations (papillomavirus binding factor peptide, survivin-2B peptide, incomplete Freund's adjuvant, and polyethylene glycol-conjugated interferon-alpha 2a) and subsequent wide necrosis and massive infiltration of CD8+ T cells in a recurrent tumor. The patient's immune responses weakened after surgical resection; however, they were reboosted following the administration of nivolumab combined with peptide vaccinations. Thus, anti-PD1 therapy combined with peptide vaccinations might be beneficial, as suggested by the observations in this sarcoma patient.

Novel therapeutic strategies for spinal osteosarcomas

At the dawn of the third millennium, cancer has become the bane of twenty-first century man, and remains a predominant public health burden, affecting welfare and life expectancy globally. Spinal osteogenic sarcoma, a primary spinal malignant tumor, is a rare and challenging neoplastic disease to treat. After the conventional therapeutic modalities of chemotherapy, radiation and surgery have been exhausted, there is currently no available alternative therapy in managing cases of spinal osteosarcoma. The defining signatures of tumor survival are characterised by cancer cell ability to stonewall immunogenic attrition and apoptosis by various means. Some of these biomarkers, namely immune-checkpoints, have recently been exploited as druggable targets in osteosarcoma and many other different cancers. These promising strides made by the use of reinvigorated immunotherapeutic approaches may lead to significant reduction in spinal osteosarcoma disease burden and corresponding reciprocity in increase of survival rates. In this review, we provide the background to spinal osteosarcoma, and proceed to elaborate on contribution of the complex ecology within tumor microenvironment giving arise to cancerous immune escape, which is currently receiving considerable attention. We follow this section on the tumor microenvironment by a brief history of cancer immunity. Also, we draw on the current knowledge of treatment gained from incidences of osteosarcoma at other locations of the skeleton (long bones of the extremities in close proximity to the metaphyseal growth plates) to make a case for application of immunity-based tools, such as immune-checkpoint inhibitors and vaccines, and draw attention to adverse upshots of immune-checkpoint blockers as well. Finally, we describe the novel biotechnique of CRISPR/Cas9 that will assist in treatment approaches for personalized medication.

Development of a T-cell receptor multimer with high avidity for detecting a naturally presented tumor-associated antigen on osteosarcoma cells

For efficacy of peptide vaccination immunotherapy for patients with cancer, endogenous expression of the target peptide/human leukocyte antigen (HLA) on cancer cells is required. However, it is difficult to evaluate the expression status of a peptide/HLA complex because of the lack of a soluble T‐cell receptor (TCR) that reacts with tumor‐associated antigen (TAA) with high avidity. In the present study, we developed two soluble TCR‐multimers that were each directed to TAA, survivin‐2B (SVN‐2B) and PBF in the context of HLA‐A24 (SVN‐2B TCR‐multimer and PBF TCR‐multimer, respectively), from CTL clones that were established from peptide‐vaccinated patients. Both TCR multimers could recognize cognate peptide‐pulsed antigen‐presenting cells, C1R‐A24 cells, in a CD8‐independent method. Moreover, the PBF TCR‐multimer successfully recognized a PBF peptide naturally presented on HLA‐A24⁺PBF⁺ osteosarcoma cells. Taken together, the results indicated that a TCR‐multimer might be useful for detection of a TAA‐derived peptide presented by HLA in patients receiving immunotherapy.

Characterization of Pattern Recognition Receptor Expression and Functionality in Liver Primary Cells and Derived Cell Lines

Different liver cell types are endowed with immunological properties, including cell-intrinsic innate immune functions that are important to initially control pathogen infections. However, a full landscape of expression and functionality of the innate immune signaling pathways in the major human liver cells is still missing. In order to comparatively characterize these pathways, we purified primary human hepatocytes, hepatic stellate cells, liver sinusoidal endothelial cells (LSEC), and Kupffer cells (KC) from human liver resections. We assessed mRNA and protein expression level of the major innate immune sensors, as well as checkpoint-inhibitor ligands in the purified cells, and found Toll-like receptors (TLR), RIG-I-like receptors, as well as several DNA cytosolic sensors to be expressed in the liver microenvironment. Amongst the cells tested, KC were shown to be most broadly active upon stimulation with PRR ligands emphasizing their predominant role in innate immune sensing the liver microenvironment. By KC immortalization, we generated a cell line that retained higher innate immune functionality as compared to THP1 cells, which are routinely used to study monocyte/macrophages functions. Our findings and the establishment of the KC line will help to understand immune mechanisms behind antiviral effects of TLR agonists or checkpoint inhibitors, which are in current preclinical or clinical development.

Irradiation enhanced the effects of PD-1 blockade in brain metastatic osteosarcoma

Brain metastasis of osteosarcoma are rare but carry a dismal prognosis. Despite the advances in both systemic immunotherapy and localized radiation, it is still difficult to treat brain metastasis, with less than 12 months of survival from the time of diagnosis for most patients. Currently, there is interest in combining strategies to take advantage of the potential synergy. In this study, the mouse model of metastatic osteosarcoma to brain was used to explore the ability of local radiation and anti-PD-1 blockade to induce beneficial anti-tumor immune responses against distant, unirradiated brain metastatic tumors. Immune markers from the peripheral blood and tumor tissue were analyzed by flow cytometry, real-time PCR and western blot. The combination treatment produced a stronger systemic anti-tumor response than either treatment alone, shown by the reduced tumor burden and larger numbers of cytotoxic CD8⁺ T cells in the unirradiated tumors, indicating an abscopal effect. These data suggested that combination treatment of irradiation with anti-PD-1 immunotherapy can induce abscopal anti-tumor responses and improve both local and distant control.

Multimodality Treatment of Desmoplastic Small Round Cell Tumor: Chemotherapy and Complete Cytoreductive Surgery Improve Patient Survival

Purpose: Desmoplastic small round cell tumor (DSRCT), which harbors EWSR1-WT1 t(11;22)(p13:q12) chromosomal translocation, is an aggressive malignancy that typically presents as intra-abdominal sarcomatosis in young males. Given its rarity, optimal treatment has not been defined.Experimental Design: We conducted a retrospective study of 187 patients with DSRCT treated at MD Anderson Cancer Center over 2 decades. Univariate and multivariate regression analyses were performed. We determined whether chemotherapy, complete cytoreductive surgery (CCS), hyperthermic intraperitoneal cisplatin (HIPEC), and/or whole abdominal radiation (WART) improve overall survival (OS) in patients with DSRCT. Critically, because our institutional practice limits HIPEC and WART to patients with less extensive, potentially resectable disease that had benefited from neoadjuvant chemotherapy, a time-variant analysis was performed to evaluate those adjunct treatment modalities.Results: The pre-2003 5-year OS rate of 5% has substantially improved to 25% with the advent of newer chemotherapies and better surgical and radiotherapy techniques (HR, 0.47; 95% CI, 0.29-0.75). Chemotherapy response (log rank P = 0.004) and CCS (log rank P < 0.0001) were associated with improved survival. Although WART and HIPEC lacked statistical significance, our study was not powered to detect their potential impact upon OS.Conclusions: Improved 3- and 5-year OS were observed following multidisciplinary treatment that includes Ewing sarcoma (ES)-based chemotherapy and complete tumor cytoreductive surgery, but few if any patients are cured. Prospective randomized studies will be required to prove whether HIPEC or WART are important. In the meantime, chemotherapy and CCS remain the cornerstone of treatment and provide a solid foundation to evaluate new biologically targeted therapies. Clin Cancer Res; 24(19); 4865-73. ©2018 AACR.

Implication of chemo-resistant memory T cells for immune surveillance in patients with sarcoma receiving chemotherapy

Chemotherapy has improved the prognosis of patients with sarcomas. However, it may suppress anti‐tumor immunity. Recently, we reported a novel CD8⁺ memory T cell population with a chemo‐resistance property, “young memory” T (T_YM) cells. In this study, we investigated the proportion and function of T_YM cells in peripheral blood of healthy donors and sarcoma patients who received chemotherapy and those who did not. The proportion of T_YM cells was significantly decreased in patients compared with that in healthy donors. In healthy donors, anti‐EBV CTLs were induced using mixed lymphocyte peptide culture, from not only T_YM cells but also T_CM and T_EM cells. No CTLs directed to tumor‐associated antigens were induced. In sarcoma patients who did not receive chemotherapy, in addition to anti‐EBV CTLs, CTLs directed to the tumor‐associated antigen PBF were induced from T_YM, T_CM and T_EM cells. In sarcoma patients who received chemotherapy, EBV‐specific CTLs were induced from T_YM cells but were hardly induced from T_EM cells. Interestingly, CTLs directed to the anti‐tumor‐associated antigen PBF were induced from T_YM cells but not from the T_CM and T_EM cells in sarcoma patients who received chemotherapy. The findings suggest that T_YM cells are resistant to chemotherapy and can firstly recover from the nadir. T_YM cells might be important for immunological memory, especially in sarcoma patients receiving chemotherapy.

Potential mechanisms underlying CDK5 related Osteosarcoma progression

OBJECTIVES

Identification of new prognostic biomarkers and therapeutic targets is of crucial importance for patients with osteosarcoma. Cyclin-dependent kinase 5 (CDK5) is overexpressed in several tumor types. However, the exact role CDK5 plays in osteosarcoma is still unknown.

METHODS

In this study, we explored the association between CDK5 expression and the prognosis of osteosarcoma patients using publicly available gene expression datasets. Potential molecular mechanisms underlying its pro-malignant role in cancer progression were also discussed.

RESULTS

We demonstrated that tricarboxylic acid (TCA) cycle is activated while antigen presentation is repressed in patients with CDK5 overexpression and poor survival. This results indicated that sufficient energy production and tumor immune escape are important characteristics and potential therapeutic targets for this subgroup of osteosarcoma patients. Furthermore, several critical hub genes that are associated with CDK5 related osteosarcoma progression such as MELK were identified.

CONCLUSION

This study discussed the pro-malignant role of CDK5 and potential mechanisms involved. Further preclinical and clinical studies to develop CDK5 based treatments are warranted.

T-Cell-Based Immunotherapy for Osteosarcoma: Challenges and Opportunities

Even though combining surgery with chemotherapy has significantly improved the prognosis of osteosarcoma patients, advanced, metastatic, or recurrent osteosarcomas are often non-responsive to chemotherapy, making development of novel efficient therapeutic methods an urgent need. Adoptive immunotherapy has the potential to be a useful non-surgical modality for treatment of osteosarcoma. Recently, alternative strategies, including immunotherapies using naturally occurring or genetically modified T cells, have been found to hold promise in the treatment of hematologic malignancies and solid tumors. In this review, we will discuss possible T-cell-based therapies against osteosarcoma with a special emphasis on combination strategies to improve the effectiveness of adoptive T cell transfer and, thus, to provide a rationale for the clinical development of immunotherapies.