New Strategies in Sarcoma: Linking Genomic and Immunotherapy Approaches to Molecular Subtype

Genomic Insights into the Role of TOP Gene Family in Soft-Tissue Sarcomas: Implications for Prognosis and Therapy

This study focuses on the role of topoisomerases (TOPs) in sarcomas (SARCs), highlighting TOPs' influence on sarcoma prognosis through mRNA expression, genetic mutations, immune infiltration, and DNA methylation analysis using transcriptase sequencing and other techniques. The findings indicate that TOP gene mutations correlate with increased inflammation, immune cell infiltration, DNA repair abnormalities, and mitochondrial fusion genes alterations, all of which negatively affect sarcoma prognosis. Abnormal TOP expression may independently affect sarcoma patients' survival. Cutting-edge genomic tools such as Oncomine, gene expression profiling interactive analysis (GEPIA), and cBio Cancer Genomics Portal (cBioPortal) are utilized to explore the TOP gene family (TOP1/1MT/2A/2B/3A/3B) in soft-tissue sarcomas (STSs). This in-depth analysis reveals a notable upregulation of TOP mRNA in STS patients arcoss various SARC subtypes, French Federation Nationale des Centres de Lutte Contre le Cancer classification (FNCLCC) grades, and specific molecular profiles correlating with poorer clinical outcomes. Furthermore, this investigation identifies distinct patterns of immune cell infiltration, genetic mutations, and somatic copy number variations linked to TOP genes that inversely affect patient survival rates. These findings underscore the diagnostic and therapeutic relevance of the TOP gene suite in STSs.

Sarcoma_CellminerCDB: A tool to interrogate the genomic and functional characteristics of a comprehensive collection of sarcoma cell lines

Sarcomas are a diverse group of rare malignancies composed of multiple different clinical and molecular subtypes. Due to their rarity and heterogeneity, basic, translational, and clinical research in sarcoma has trailed behind that of other cancers. Outcomes for patients remain generally poor due to an incomplete understanding of disease biology and a lack of novel therapies. To address some of the limitations impeding preclinical sarcoma research, we have developed Sarcoma_CellMinerCDB, a publicly available interactive tool that merges publicly available sarcoma cell line data and newly generated omics data to create a comprehensive database of genomic, transcriptomic, methylomic, proteomic, metabolic, and pharmacologic data on 133 annotated sarcoma cell lines. The reproducibility, functionality, biological relevance, and therapeutic applications of Sarcoma_CellMinerCDB described herein are powerful tools to address and generate biological questions and test hypotheses for translational research. Sarcoma_CellMinerCDB (https://discover.nci.nih.gov/SarcomaCellMinerCDB) aims to contribute to advancing the preclinical study of sarcoma.

Single-agent temozolomide as salvage therapy in heavily pretreated metastatic sarcoma patients

BACKGROUND

Treatment options for patients with metastatic sarcoma are limited. The goal of this study was to investigate the effectiveness of temozolomide in pretreated patients with soft tissue sarcoma.

METHODS

We recorded the pathological, clinical, and treatment data of the patients with metastatic soft tissue sarcoma retrospectively. We evaluated the efficacy and side effects of temozolomide in this patient group.

RESULTS

This study involved 16 patients. The average age was detected as 48 (21-73) years. Six (37.5%) patients had de-novo metastatic disease at diagnosis. Primary of tumors had originated from intra-abdominal (43.7%), extremity (31.3%), head-and-neck (12.5%), and intrathoracic (12.5%) regions. The patients previously had received at least two different chemotherapy regimens (75%), pazopanib (50%) and palliative radiotherapy (31.3%). Temozolomide-related median progression-free survival time was found as 3.5 (95% CI, 2.6-4.3) months. One patient (6.3%) had a partial response, while four patients (25%) had stable disease. Nine individuals (56.3%) had grade 1-2 adverse events, while one patient (6.3%) had grade 3-4 adverse events.

CONCLUSIONS

We observed that temozolomide was well tolerated but had limited efficacy in the treatment of metastatic sarcoma patients. In patients with extensively pretreated soft tissue sarcoma, temozolomide may be considered a therapeutic option as a single-agent.

circCsnk1g3- and circAnkib1-regulated interferon responses in sarcoma promote tumorigenesis by shaping the immune microenvironment

Exonic circular RNAs (circRNAs) produce predominantly non-coding RNA species that have been recently profiled in many tumors. However, their functional contribution to cancer progression is still poorly understood. Here, we identify the circRNAs expressed in soft tissue sarcoma cells and explore how the circRNAs regulate sarcoma growth in vivo. We show that circCsnk1g3 and circAnkib1 promote tumor growth by shaping a pro-tumorigenic microenvironment, possibly due to their capabilities to regulate tumor-promoting elements extrinsic to the tumor cells. Accordingly, circCsnk1g3 and circAnkib1 can control the expression of interferon-related genes and pro-inflammatory factors in the sarcoma cells, thus directing immune cell recruitment into the tumor mass, and hence their activation. Mechanistically, circRNAs may repress pro-inflammatory elements by buffering activation of the pathways mediated by RIG-I, the cytosolic viral RNA sensor. The current findings suggest that the targeting of specific circRNAs could augment the efficacy of tumor and immune response to mainstay therapies.

Improving Immunotherapy Efficacy in Soft-Tissue Sarcomas: A Biomarker Driven and Histotype Tailored Review

Anti-PD-(L)1 therapies yield a disappointing response rate of 15% across soft-tissue sarcomas, even if some subtypes benefit more than others. The proportions of TAMs and TILs in their tumor microenvironment are variable, and this heterogeneity correlates to histotype. Tumors with a richer CD8+ T cell, M1 macrophage, and CD20+ cells infiltrate have a better prognosis than those infiltrated by M0/M2 macrophages and a high immune checkpoint protein expression. PD-L1 and CD8+ infiltrate seem correlated to response to immune checkpoint inhibitors (ICI), but tertiary lymphoid structures have the best predictive value and have been validated prospectively. Trials for combination therapies are ongoing and focus on the association of ICI with chemotherapy, achieving encouraging results especially with pembrolizumab and doxorubicin at an early stage, or ICI with antiangiogenics. A synergy with oncolytic viruses is seen and intratumoral talimogene laherpavec yields an impressive 35% ORR when associated to pembrolizumab. Adoptive cellular therapies are also of great interest in tumors with a high expression of cancer-testis antigens (CTA), such as synovial sarcomas or myxoid round cell liposarcomas with an ORR ranging from 20 to 50%. It seems crucial to adapt the design of clinical trials to histology. Leiomyosarcomas are characterized by complex genomics but are poorly infiltrated by immune cells and do not benefit from ICI. They should be tested with PIK3CA/AKT inhibition, IDO blockade, or treatments aiming at increasing antigenicity (radiotherapy, PARP inhibitors). DDLPS are more infiltrated and have higher PD-L1 expression, but responses to ICI remain variable across clinical studies. Combinations with MDM2 antagonists or CDK4/6 inhibitors may improve responses for DDLPS. UPS harbor the highest copy number alterations (CNA) and mutation rates, with a rich immune infiltrate containing TLS. They have a promising 15-40% ORR to ICI. Trials for ICB should focus on immune-high UPS. Association of ICI with FGFR inhibitors warrants further exploration in the immune-low group of UPS. Finally translocation-related sarcomas are heterogeneous, and although synovial sarcomas a poorly infiltrated and have a poor response rate to ICI, ASPS largely benefit from ICB monotherapy or its association with antiangiogenics agents. Targeting specific neoantigens through vaccine or adoptive cellular therapies is probably the most promising approach in synovial sarcomas.

Molecular Determinants of Soft Tissue Sarcoma Immunity: Targets for Immune Intervention

Soft tissue sarcomas (STSs) are a family of rare malignant tumors encompassing more than 80 histologies. Current therapies for metastatic STS, a condition that affects roughly half of patients, have limited efficacy, making innovative therapeutic strategies urgently needed. From a molecular point of view, STSs can be classified as translocation-related and those with a heavily rearranged genotype. Although only the latter display an increased mutational burden, molecular profiles suggestive of an “immune hot” tumor microenvironment are observed across STS histologies, and response to immunotherapy has been reported in both translocation-related and genetic complex STSs. These data reinforce the notion that immunity in STSs is multifaceted and influenced by both genetic and epigenetic determinants. Cumulative evidence indicates that a fine characterization of STSs at different levels is required to identify biomarkers predictive of immunotherapy response and to discover targetable pathways to switch on the immune sensitivity of “immune cold” tumors. In this review, we will summarize recent findings on the interplay between genetic landscape, molecular profiling and immunity in STSs. Immunological and molecular features will be discussed for their prognostic value in selected STS histologies. Finally, the local and systemic immunomodulatory effects of the targeted drugs imatinib and sunitinib will be discussed.

Sarcoma Metabolomics: Current Horizons and Future Perspectives

The vast array of metabolic adaptations that cancer cells are capable of assuming, not only support their biosynthetic activity, but also fulfill their bioenergetic demands and keep their intracellular reduction-oxidation (redox) balance. Spotlight has recently been placed on the energy metabolism reprogramming strategies employed by cancer cells to proliferate. Knowledge regarding soft tissue and bone sarcomas metabolome is relatively sparse. Further characterization of sarcoma metabolic landscape may pave the way for diagnostic refinement and new therapeutic target identification, with benefit to sarcoma patients. This review covers the state-of-the-art knowledge on cancer metabolomics and explores in detail the most recent evidence on soft tissue and bone sarcoma metabolomics.

Defining muscle-invasive bladder cancer immunotypes by introducing tumor mutation burden, CD8+ T cells, and molecular subtypes

Immunotherapy, especially anti-PD-1, is becoming a pillar of modern muscle-invasive bladder cancer (MIBC) treatment. However, the objective response rates (ORR) are relatively low due to the lack of precise biomarkers to select patients. Herein, the molecular subtype, tumor mutation burden (TMB), and CD8+ T cells were calculated by the gene expression and mutation profiles of MIBC patients. MIBC immunotypes were constructed using clustering analysis based on tumor mutation burden, CD8+ T cells, and molecular subtypes. Mutated genes, enriched functional KEGG pathways and GO terms, and co-expressed network-specific hub genes have been identified. We demonstrated that ORR of immunotype A patients identified by molecular subtype, CD8+ T cells, and TMB is about 36% predictable. PIK3CA, RB1, FGFR3, KMT2C, MACF1, RYR2, and EP300 are differentially mutated among three immunotypes. Pathways such as ECM-receptor interaction, PI3K-Akt signaling pathway, and TGF-beta signaling pathway are top-ranked in enrichment analysis. Low expression of ACTA2 was associated with the MIBC survival benefit. The current study constructs a model that could identify suitable MIBC patients for immunotherapy, and it is an important step forward to the personalized treatment of bladder cancers.

Sarcomas: Immune biomarker expression and checkpoint inhibitor trials

Sarcomas are a heterogenous group of mesenchymal cancers comprising over 100 subtypes. Current chemotherapy for all but a very few subtypes has limited efficacy, resulting in 5-year relative survival rates of 16% for metastatic patients. While sarcomas have often been regarded as an "immune cold" tumor category, recent biomarker studies have confirmed a great deal of immune heterogeneity across sarcoma subtypes. Reports from the first generation of clinical trials treating sarcomas with immunotherapy demonstrate a few positive responses, supporting efforts to stratify patients to optimize response rates. This review summarizes recent advances in knowledge around immune biomarker expression in sarcomas, the potential use of new technologies to complement these study results, and clinical trials particularly of immune checkpoint inhibitor therapy in sarcomas. Each of the immune biomarkers assessed was reviewed for subtype-specific expression patterns and correlation with prognosis. Overall, there is extensive heterogeneity of immune biomarker presence across sarcoma subtypes, and no consensus on the prognostic effect of these biomarkers. New technologies such as multiplex immunohistochemistry and high plex in situ profiling may offer more insights into the sarcoma microenvironment. To date, clinical trials using immune checkpoint inhibitor monotherapy have not shown compelling clinical benefits. Combination therapy with dual checkpoint inhibitors or in combinations with other agents has yielded more promising results in dedifferentiated liposarcoma, undifferentiated pleomorphic sarcoma, angiosarcoma and alveolar soft-part sarcoma. Better understanding of the sarcoma immune status through biomarkers may help decipher the reasons behind differential responses to immunotherapy.

3D Culture Modelling: An Emerging Approach for Translational Cancer Research in Sarcomas

Sarcomas are tumours of mesenchymal origin, which can arise in bone or soft tissues. They are rare but frequently quite aggressive and with a poor outcome. New approaches are needed to characterise these tumours and their resistance mechanisms to current therapies, responsible for tumour recurrence and treatment failure. This review is focused on the potential of three-dimensional (3D) in vitro models, including multicellular tumour spheroids (MCTS) and organoids, and the latest data about their utility for the study on important properties for tumour development. The use of spheroids as a particularly valuable alternative for compound high throughput screening (HTS) in different areas of cancer biology is also discussed, which enables the identification of new therapeutic opportunities in commonly resistant tumours.

Predicting the Efficacy and Safety of TACTICs (Tumor Angiogenesis-Specific CAR-T Cells Impacting Cancers) Therapy for Soft Tissue Sarcoma Patients

Simple Summary

Sarcomas have few effective treatment options due to the rarity and diversity and have a high risk of recurrence and metastasis. Therefore, the development of new therapeutics that can meet their medical needs is required. Our adoptive immunotherapy strategy using T cells to express the chimeric antigen receptor (CAR) against vascular endothelial growth factor receptor 2 (VEGFR2), which is highly expressed on tumor vascular endothelial cells, has the potential to be a novel treatment against diverse sarcomas with abundant vascular invasion. Here, we optimized the manufacturing and transportation of anti-VEGFR2 CAR-mRNA-transfected T cells and collected information that allowed the extrapolation of their efficacy and safety potential for sarcoma patients. Our results support the development of a “first in humans” study to evaluate the potential of our anti-VEGFR2 CAR-T cell therapy as a new treatment option for sarcoma patients.

Abstract

Soft tissue sarcomas (STSs) are heterogeneous and aggressive malignancies with few effective therapies available. We have developed T cells expressing a vascular endothelial growth factor receptor 2 (VEGFR2)-specific chimeric antigen receptor (CAR) to establish a tumor angiogenesis-specific CAR-T cells impacting cancers (TACTICs) therapy. In this study, we optimized the manufacturing and transportation of mRNA-transfected anti-VEGFR2 CAR-T cells and collected information that allowed the extrapolation of the efficacy and safety potential of TACTICs therapy for STS patients. Although 5-methoxyuridines versus uridines did not improve CAR-mRNA stability in T cells, the utilization of CleanCap as a 5′ cap-structure extended the CAR expression level, increasing VEGFR2-specific cytotoxicity. Furthermore, 4 °C preservation conditions did not affect the viability/cytotoxicity of CAR-T cells, contrarily to a freeze-thaw approach. Importantly, immunohistochemistry showed that most of the STS patients’ specimens expressed VEGFR2, suggesting a great potential of our TACTICs approach. However, VEGFR2 expression was also detected in normal tissues, stressing the importance of the application of a strict monitoring schedule to detect (and respond to) the occurrence of adverse effects in clinics. Overall, our results support the development of a “first in humans” study to evaluate the potential of our TACTICs therapy as a new treatment option for STSs.

Glycogen Synthase Kinase 3β in Cancer Biology and Treatment

Glycogen synthase kinase (GSK)3β is a multifunctional serine/threonine protein kinase with more than 100 substrates and interacting molecules. GSK3β is normally active in cells and negative regulation of GSK3β activity via phosphorylation of its serine 9 residue is required for most normal cells to maintain homeostasis. Aberrant expression and activity of GSK3β contributes to the pathogenesis and progression of common recalcitrant diseases such as glucose intolerance, neurodegenerative disorders and cancer. Despite recognized roles against several proto-oncoproteins and mediators of the epithelial–mesenchymal transition, deregulated GSK3β also participates in tumor cell survival, evasion of apoptosis, proliferation and invasion, as well as sustaining cancer stemness and inducing therapy resistance. A therapeutic effect from GSK3β inhibition has been demonstrated in 25 different cancer types. Moreover, there is increasing evidence that GSK3β inhibition protects normal cells and tissues from the harmful effects associated with conventional cancer therapies. Here, we review the evidence supporting aberrant GSK3β as a hallmark property of cancer and highlight the beneficial effects of GSK3β inhibition on normal cells and tissues during cancer therapy. The biological rationale for targeting GSK3β in the treatment of cancer is also discussed at length.

Sarcomas-A barren immunological wasteland or field of opportunity for immunotherapy?

Key advances in our understanding of immunobiology and the immunosuppressive mechanisms of the tumour microenvironment have led to significant breakthroughs in manipulating the immune system to successfully treat cancer. Remarkable therapeutic responses have occurred with tumours that carry a high mutational burden. In these cases, pre-existing tumour-specific T cells can be rejuvenated via checkpoint inhibition to eliminate tumours. Furthermore, durable remissions have been achieved in haematological malignancies following adoptive transfer of T cells that specifically target cell surface proteins where expression is restricted to the malignancy's cell of origin. Soft tissue sarcomas and bone sarcomas have a paucity of non-synonymous somatic mutations and do not commonly express known, targetable, tumour-specific antigens. Historically, soft tissue sarcomas have been considered immunologically 'cold' and as such, unlikely candidates for immune therapy. Here, we review the immune landscape of canine and feline sarcomas and the immunotherapeutic strategies that have been employed in veterinary clinical trials to improve patient outcome. We also provide insight into immunotherapeutic approaches being used to treat human sarcomas. Together, current data indicates that, rather than a barren immunological wasteland, sarcomas represent a field of opportunities for immunotherapies. Furthermore, we and others would suggest that strategic combinations of immunotherapeutic approaches may hold promise for more effective treatments for high grade soft tissue sarcomas and bone sarcomas.

TGFβ and Hippo Pathways Cooperate to Enhance Sarcomagenesis and Metastasis through the Hyaluronan-Mediated Motility Receptor (HMMR)

High-grade sarcomas are metastatic and pose a serious threat to patient survival. Undifferentiated pleomorphic sarcoma (UPS) is a particularly dangerous and relatively common sarcoma subtype diagnosed in adults. UPS contains large quantities of extracellular matrix (ECM) including hyaluronic acid (HA), which is linked to metastatic potential. Consistent with these observations, expression of the HA receptor, hyaluronan-mediated motility receptor (HMMR/RHAMM), is tightly controlled in normal tissues and upregulated in UPS. Moreover, HMMR expression correlates with poor clinical outcome in these patients. Deregulation of the tumor-suppressive Hippo pathway is also linked to poor outcome in these patients. YAP1, the transcriptional regulator and central effector of Hippo pathway, is aberrantly stabilized in UPS and was recently shown to control RHAMM expression in breast cancer cells. Interestingly, both YAP1 and RHAMM are linked to TGFβ signaling. Therefore, we investigated crosstalk between YAP1 and TGFβ resulting in enhanced RHAMM-mediated cell migration and invasion. We observed that HMMR expression is under the control of both YAP1 and TGFβ and can be effectively targeted with small-molecule approaches that inhibit these pathways. Furthermore, we found that RHAMM expression promotes tumor cell proliferation and migration/invasion. To test these observations in a robust and quantifiable in vivo system, we developed a zebrafish xenograft assay of metastasis, which is complimentary to our murine studies. Importantly, pharmacologic inhibition of the TGFβ-YAP1-RHAMM axis prevents vascular migration of tumor cells to distant sites. IMPLICATIONS: These studies reveal key metastatic signaling mechanisms and highlight potential approaches to prevent metastatic dissemination in UPS.YAP1 and TGFβ cooperatively enhance proliferation and migration/invasion of UPS and fibrosarcomas.

The changing landscape of phase II/III metastatic sarcoma clinical trials-analysis of ClinicalTrials.gov

Background

Well-designed clinical trials are of great importance in validating novel treatments and ensuring an evidence-based approach for sarcoma. This study aimed to provide a comprehensive landscape of the characteristics of metastatic or advanced sarcoma clinical trials using the substantial resource of the ClincialTrials.gov database.

Methods

We identified 260,755 trials registered with ClinicalTrials.gov in the last 20 years, and 277 of them were eligible for inclusion. The baseline characteristics were ascertained for each trial. The trials were systematically reviewed to validate their classification into 96 trials registered before 2008 and 181 trials registered between 2008 and 2017.

Results

We found that in the last decade, metastatic and advanced sarcoma trials were predominantly phase II-III studies (p = 0.048), were more likely to be ≥2 arms (17.7% vs 35.3%, respectively; p = 0.007), and were more likely to use randomized (13.5% vs 30.4%; p = 0.002) and double-blinded (2.1% vs 9.4%; p = 0.024) assignment than trials registered before 2008. Furthermore, in the last 10-year period, metastatic sarcoma trials were more likely to be conducted in Asia. Treatment involving target therapy and immunotherapy were more common (71.8% vs 37.5%; p < 0.001) than in previous years.

Conclusions

Our data showed provocative changes in the sarcoma landscape and demonstrated that the incidence of clinical trials with target therapy and immunotherapy is increasing. These findings emphasize the desperate need for novel strategies, including target therapy and immunotherapy, to improve the outcomes for patients with advanced sarcoma.

Electronic supplementary material

The online version of this article (10.1186/s12885-018-5163-2) contains supplementary material, which is available to authorized users.

Phase II study of neoadjuvant checkpoint blockade in patients with surgically resectable undifferentiated pleomorphic sarcoma and dedifferentiated liposarcoma

BACKGROUND

Soft tissue sarcomas are a heterogeneous and rare group of solid tumors of mesenchymal origin that can arise anywhere in the body. Although surgical resection is the mainstay of treatment for patients with localized disease, disease recurrence is common and 5-year overall survival is poor (~ 65%). Both radiation therapy and conventional chemotherapy are used to reduce local and distant recurrence. However, the utility of radiation therapy is often limited by disease location (in the case of retroperitoneal sarcomas, for instance) while systemic therapy with conventional lines of chemotherapy offer limited efficacy and are often poorly tolerated and associated with significant toxicity. Within the past decade, major advances have been made in the treatment of other malignancies including melanoma, renal cell carcinoma, and non-small cell lung carcinoma with the advent of immune-checkpoint inhibitors such as ipilimumab (anti-CTLA4), pembrolizumab (anti-PD1), and nivolumab (anti-PD1). The recently published SARC028 (NCT02301039), an open label, phase II, multicenter trial of pembrolizumab in patients with advanced bone and soft tissue sarcomas reported promising activity in select histologic subtypes of advanced STS, including undifferentiated pleomorphic sarcoma and dedifferentiated liposarcoma.

METHODS

There is a clear need for novel and effective adjuncts in the treatment of STS. We hypothesize that immune checkpoint blockade will be effective in patients with surgically resectable primary or locally recurrent dedifferentiated liposarcoma and undifferentiated pleomorphic sarcoma when administered in the neoadjuvant setting. The primary aim of this phase II, single-center, open label, randomized non-comparative trial is to determine the pathologic response to neoadjuvant nivolumab monotherapy and combination nivolumab/ipilimumab in patients with resectable dedifferentiated liposarcoma of the retroperitoneum or undifferentiated pleomorphic sarcoma of the trunk or extremity treated with concurrent standard of care neoadjuvant radiation therapy.

DISCUSSION

This study will help define the role of single agent anti-PD1 and combination anti-CTLA4 and anti-PD1 therapy in patients with surgically resectable dedifferentiated liposarcoma and undifferentiated pleomorphic sarcoma.

TRIAL REGISTRATION

ClinicalTrials.gov NCT03307616 , registered October 12, 2017.

YAP1-Mediated Suppression of USP31 Enhances NFκB Activity to Promote Sarcomagenesis

To date, no consistent oncogenic driver mutations have been identified in most adult soft tissue sarcomas; these tumors are thus generally insensitive to existing targeted therapies. Here we investigated alternate mechanisms underlying sarcomagenesis to identify potential therapeutic interventions. Undifferentiated pleomorphic sarcoma (UPS) is an aggressive tumor frequently found in skeletal muscle where deregulation of the Hippo pathway and aberrant stabilization of its transcriptional effector yes-associated protein 1 (YAP1) increases proliferation and tumorigenesis. However, the downstream mechanisms driving this deregulation are incompletely understood. Using autochthonous mouse models and whole genome analyses, we found that YAP1 was constitutively active in some sarcomas due to epigenetic silencing of its inhibitor angiomotin (AMOT). Epigenetic modulators vorinostat and JQ1 restored AMOT expression and wild-type Hippo pathway signaling, which induced a muscle differentiation program and inhibited sarcomagenesis. YAP1 promoted sarcomagenesis by inhibiting expression of ubiquitin-specific peptidase 31 (USP31), a newly identified upstream negative regulator of NFκB signaling. Combined treatment with epigenetic modulators effectively restored USP31 expression, resulting in decreased NFκB activity. Our findings highlight a key underlying molecular mechanism in UPS and demonstrate the potential impact of an epigenetic approach to sarcoma treatment.Significance: A new link between Hippo pathway signaling, NFκB, and epigenetic reprogramming is highlighted and has the potential for therapeutic intervention in soft tissue sarcomas. Cancer Res; 78(10); 2705-20. ©2018 AACR.

Phosphorylation of EZH2 by AMPK Suppresses PRC2 Methyltransferase Activity and Oncogenic Function

Sustained energy starvation leads to activation of AMP-activated protein kinase (AMPK), which coordinates energy status with numerous cellular processes including metabolism, protein synthesis, and autophagy. Here, we report that AMPK phosphorylates the histone methyltransferase EZH2 at T311 to disrupt the interaction between EZH2 and SUZ12, another core component of the polycomb repressive complex 2 (PRC2), leading to attenuated PRC2-dependent methylation of histone H3 at Lys27. As such, PRC2 target genes, many of which are known tumor suppressors, were upregulated upon T311-EZH2 phosphorylation, which suppressed tumor cell growth both in cell culture and mouse xenografts. Pathologically, immunohistochemical analyses uncovered a positive correlation between AMPK activity and pT311-EZH2, and higher pT311-EZH2 correlates with better survival in both ovarian and breast cancer patients. Our finding suggests that AMPK agonists might be promising sensitizers for EZH2-targeting cancer therapies.

Immune checkpoint inhibitors in sarcomas: in quest of predictive biomarkers

Sarcomas are a rare group of tumors of mesenchymal origin. Metastatic sarcomas are often difficult to treat and unresponsive to standard radio- and chemotherapy, resulting in a poor survival rate for patients. Novel treatments with immune checkpoint inhibitors have been proven to prolong survival of patients with a variety of cancers, including metastatic melanoma, lung, and renal cell carcinoma. Since immune checkpoint inhibitors could provide a novel treatment option for patients with sarcomas, clinical trials investigating their efficacy in these group of tumors are ongoing. However, the discrimination of patients that are the most likely to respond to these treatments is still an obstacle in the design of clinical trials. In this review, we provide a brief overview of the mechanisms of action of immune checkpoint inhibitors and discuss the proposed biomarkers of therapy response, such as lymphocytic infiltration, intratumoral PD-L1 expression, and mutational load in sarcomas.

Analysis of the immune infiltrate in undifferentiated pleomorphic sarcoma of the extremity and trunk in response to radiotherapy: Rationale for combination neoadjuvant immune checkpoint inhibition and radiotherapy

Background: Undifferentiated pleomorphic sarcoma of the extremity and trunk (ET-UPS) presents a unique therapeutic challenge. Although immunotherapy has recently been employed in advanced soft tissue sarcoma, there is limited data characterizing the immune infiltrate in ET-UPS. Radiotherapy (RT) has been shown in other tumor types to promote tumor antigen release and enhance tumor-specific targeting by the adaptive immune system. The aim of this study was to 1) characterize the baseline immune infiltrate and 2) evaluate the effect of preoperative RT on the histologic appearance of and the immune infiltrate in ET-UPS. Methods: We identified 17 matched ET-UPS samples before and after RT. Immunohistochemistry was performed with CD8, CD4, PD-L1, PD1, CD3, CD163 and FoxP3 positive cells identified in all samples. Changes in the immune infiltrate following RT were examined. Results: There was a trend towards increased density of tumor infiltrating immune cells in ET-UPS following RT, with increases in median number of CD3 (158 vs 219 cells/mm2, p = 0.06), CD4 (3 vs 13 cells/mm2, p = 0.01), CD8 (55 vs 111 cells/mm2, p = 0.17), and FOXP3 (14 vs 25 cells/mm2, p = 0.23) positive cells. Interestingly, although PD-L1 was not expressed in any ET-UPS tumor at baseline, positive PD-L1 expression was observed in 21% (3/14) of tumors after RT (p = 0.07). Conclusion: An immune infiltrate is present in ET-UPS at the time of diagnosis, with a trend towards increased density of immune infiltrate and PD-L1 expression after RT. These data support prospectively evaluating immune checkpoint inhibitors with standard of care RT in the treatment of ET-UPS.

Increased infiltration of M2-macrophages, T-cells and PD-L1 expression in high grade leiomyosarcomas supports immunotherapeutic strategies

Background: Immunotherapy may be a rational strategy in leiomyosarcoma (LMS), a tumor known for its genomic complexity. As a prerequisite for therapeutic applications, we characterized the immune microenvironment in LMS, as well as its prognostic value. Methods: CD163⁺ macrophages, CD3⁺ T-cells, PD-L1/PD-L2 and HLA class I expression (HCA2, HC10 and β2m) were evaluated using immunohistochemistry in primary tumors (n = 75), local relapses (n = 6) and metastases (n = 19) of 87 LMS patients, as well as in benign leiomyomas (n = 7). Correlation with clinicopathological parameters and survival analyses were assessed. Effect of LMS cells on macrophage differentiation was investigated using coculture of CD14⁺ monocytes with LMS cell lines or their conditioned media (CM). Results: 58% and 52% of the tumors were highly infiltrated with CD163⁺ macrophages and T-cells, respectively, with HLA class I expression observed in almost all tumors and PD-L1 expression in 30%. PD-L2 expression was also detected in some PD-L1⁺ tumors. All these immune markers correlated with high tumor grade but only CD163 associated with overall survival (p = 0.003) and disease-specific survival (p = 0.041). In vitro, CD163 was upregulated in the presence of LMS cells producing M-CSF, suggesting that this tumor drives macrophages towards the M2 phenotype. Conclusion: The clinical significance of M2 macrophages, possibly induced by LMS cell-secreted factors, suggests that 2/3 of high-grade LMS patients might benefit from macrophage-targeting agents. Furthermore, PD-L1 expression together with high T-cell infiltrate and HLA class I expression in around 30% of high grade LMS reflects an active immune microenvironment potentially responsive to immune checkpoint inhibitors.

Molecular Pathogenesis and Diagnostic, Prognostic and Predictive Molecular Markers in Sarcoma

Sarcomas are infrequent mesenchymal neoplasms characterized by notable morphological and molecular heterogeneity. Molecular studies in sarcoma provide refinements to morphologic classification, and contribute diagnostic information (frequently), prognostic stratification (rarely) and predict therapeutic response (occasionally). Herein, we summarize the major molecular mechanisms underlying sarcoma pathogenesis and present clinically useful diagnostic, prognostic and predictive molecular markers for sarcoma. Five major molecular alterations are discussed, illustrated with representative sarcoma types, including 1. the presence of chimeric transcription factors, in vascular tumors; 2. abnormal kinase signaling, in gastrointestinal stromal tumor; 3. epigenetic deregulation, in chondrosarcoma, chondroblastoma, and other tumors; 4. deregulated cell survival and proliferation, due to focal copy number alterations, in dedifferentiated liposarcoma; 5. extreme genomic instability, in conventional osteosarcoma as a representative example of sarcomas with highly complex karyotype.

Targeted treatments of sarcomas and connective tumors beside gastrointestinal stromal tumor

PURPOSE OF REVIEW

Sarcoma is a heterogeneous group of malignancies historically treated with classic cytotoxic chemotherapy. This review updates the recent advances in targeted therapies in soft-tissue sarcoma, bone sarcoma and other connective diseases with local aggressiveness.

RECENT FINDINGS

Platelet-derived growth factor receptor (PDGFR) inhibitors, antiangiogenics, cell cycle inhibitors and immunomodulatory agents are the main targeted therapies in development in sarcoma. PDGFRα inhibitor olaratumab is being evaluated in a phase III trial in combination with doxorubicin against doxorubicin in monotherapy and, in case of positive results, it could change the standard in the first-line setting. Immunotherapy is still in the early phases of development, although some data in synovial sarcoma are promising. Targeted agents are also in development in other mesenchymal neoplasms, such as the inhibitor of colony stimulating factor 1 receptor for pigmented villonodular synovitis.

SUMMARY

Several targeted therapies are in development in sarcoma and could be added to the therapeutic armamentarium in the near future. However, predictive factors still need to be identified to better select the target population of these new drugs.

Anti-angiogenesis target therapy for advanced osteosarcoma (Review)

Osteosarcomas (OS), especially those with metastatic or unresectable disease, have limited treatment options. The greatest advancement in treatments occurred in the 1980s when multi-agent chemotherapy, including doxorubicin, cisplatin, high-dose methotrexate, and, in some regimens, ifosfamide, was demonstrated to improve overall survival compared with surgery alone. However, standard chemotherapeutic options have been limited by poor response rates in patients with relapsed or advanced cases. It has been reported that VEGFR expression correlates with the outcome of patients with osteosarcoma and circulating VEGF level has been associated with the development of lung metastasis. At present, it seems to us that progress has not been made since Grignani reported a phase II cohort trial of sorafenib and sorafenib combined with everolimus for advanced osteosarcoma, which, in a sense, have become a milestone as a second-line therapy for osteosarcoma. Although the recognization of muramyltripepetide phosphatidyl-ethanolamine has made some progress based on its combination with standard chemotherapy, its effect on refractory cases is controversial. Personalized comprehensive molecular profiling of high-risk osteosarcoma up to now has not changed the therapeutic prospect of advanced osteosarcoma significantly. Thus, how far have we moved forward and what therapeutic strategy should we prefer for anti-angiogenesis therapy? This review provides an overview of the most updated anti-angiogenesis therapy in OS and discusses some clinical options in order to maintain or even improve progression-free survival.

Significance of Phosphorylated Epidermal Growth Factor Receptor and Its Signal Transducers in Human Soft Tissue Sarcoma

Previous studies have shown that total epidermal growth factor receptor (EGFR) protein is highly expressed in soft tissue sarcoma (STS). We aimed to investigate the significance of phosphorylated-EGFR (pEGFR) and its activated-downstream signal transducers in STS tissue samples. A tissue microarray comprising 87 STS samples was assessed for total EGFR, pEGFR and its phosphorylated signal transducers and expression was correlated with clinicopathlogical parameters including patient outcome. Although the expression of total EGFR was significantly associated with adverse STS histologic grade (p = 0.004) and clinical stage (p = 0.012) similar to pEGFR, phosphorylated protein kinase B (pAkt) and phosphorylated extracellular signal regulated kinase (pERK), it is not a prognostic factor for survival. By contrast, the expression of pEGFR is an independent factor for cancer specific survival, while pERK is an independent prognostic factor for both overall and cancer specific survival in STS (p < 0.05, Cox proportional hazard model and log-rank test) in addition to the recognised factors of tumour grade and clinical stage. pERK and pEGFR are new independent prognostic factors for overall and/or cancer specific survival in STS. The expression of EGFR/pEGFR, and their associated downstream signal transducers, was associated with STS progression, suggesting that EGFR downstream signalling pathways may jointly support STS cell survival.

Update on molecular findings in rhabdomyosarcoma

Rhabdomyosarcoma (RMS) is the most common malignant soft tissue tumour in children and adolescents. Histologically RMS resembles developing fetal striated skeletal muscle. RMS is stratified into different histological subtypes which appear to influence management plans and patient outcome. Importantly, molecular classification of RMS seems to more accurately capture the true biology and clinical course and prognosis of RMS to guide therapeutic decisions. The identification of PAX-FOXO1 fusion status in RMS is one of the most important updates in the risk stratification of RMS. There are several genes close to PAX that are frequently altered including the RAS family, FGFR4, PIK3CA, CTNNB1, FBXW7, and BCOR. As with most paediatric blue round cell tumours and sarcomas, chemotherapy is the key regimen for RMS therapy. Currently there are no direct inhibitors against PAX-FOXO1 fusion oncoproteins and targeting epigenetic cofactors is limited to clinical trials. Failure of therapy in RMS is usually related to drug resistance and metastatic disease. Through this review we have highlighted most of the molecular aspects in RMS and have attempted to correlate with RMS classification, treatment and prognosis.

Response to anti-PD1 therapy with nivolumab in metastatic sarcomas

BACKGROUND

Manipulation of immune checkpoints such as CTLA4 or PD-1 with targeted antibodies has recently emerged as an effective anticancer strategy in multiple malignancies. Sarcomas are a heterogeneous group of diseases in need of more effective treatments. Different subtypes of soft tissue and bone sarcomas have been shown to express PD-1 ligand.

METHODS

We retrospectively analyzed a cohort of patients (pts) with relapsed metastatic/unresectable sarcomas, who were treated with nivolumab provided under a patient assistance program from the manufacturer. Pts underwent CT or PET/CT imaging at baseline and after at least four doses of nivolumab; RECIST 1.1 criteria were used for response assessment.

RESULTS

Twenty-eight pts with soft tissue (STS, N = 24) or bone sarcoma (N = 4), received IV nivolumab 3 mg/kg every 2 weeks from July 2015. Median age was 57 (24-78), male:female ratio was 14:14; the median number of nivolumab cycles was eight. Eighteen pts concomitantly received pazopanib at 400-800 mg daily. The most common side effect was grade 1-2 LFT elevations; grade 3-4 toxicity occurred in five patients (colitis, LFT elevations, pneumonitis). Twenty-four pts received at least four cycles. We observed three partial responses: one dedifferentiated chondrosarcoma, one epithelioid sarcoma and one maxillary osteosarcoma (last two patients on pazopanib); nine patients had stable disease including three leiomyosarcomas; 12 patients had progression of disease including 4 leiomyosarcoma. Clinical benefit (response + stability) was observed in 50% of the evaluable patients.

CONCLUSIONS

These data provide a rationale for further exploring the efficacy of nivolumab and other checkpoint inhibitors in soft tissue and bone sarcoma.

Increased PD-L1 and T-cell infiltration in the presence of HLA class I expression in metastatic high-grade osteosarcoma: a rationale for T-cell-based immunotherapy

Introduction

Immunotherapy may be an excellent choice for treating osteosarcoma given its exceptionally high genomic instability, potentially generating neoantigens. In this study, we aim to investigate the HLA class I expression, PD-L1 and tumour-infiltrating lymphocytes in primary osteosarcomas and relapses/metastases, as well as their changes during disease progression.

Materials and methods

Tumour samples from multiple stages of the disease (pretreatment biopsies, surgical resections of primary osteosarcomas, relapses and metastases) were collected and stained for HLA-A (HCA2), HLA-B/C (HC10), β2-microglobulin and PD-L1 using immunohistochemistry on whole sections. Density and type of T-cell infiltrate were characterised by a triple immunofluorescent staining CD3-CD8-FOXP3.

Results

Overall, 85 formalin-fixed, paraffin-embedded blocks from 25 osteosarcoma patients were included. HLA class I expression was detected in 94% of osteosarcomas (strongly positive in 56%, heterogeneous in 38%) and negative or weakly positive in 6%, without differences between the stages of the disease. HLA-A expression was more frequently negative than HLA-B/C. Tumour-infiltrating lymphocytes were highly heterogeneous and mainly observed in tumour areas with expression of HLA class I. Density of T cells was significantly higher in metastases than in primary tumours and local relapses (p = 0.0003). Positive PD-L1 expression was found in 13% of primary tumours, 25% of relapses and 48% of metastases and correlated with a high T-cell infiltrate (p = 0.002).

Conclusion

An increased number of tumour-infiltrating T cells and PD-L1 expression in metastases compared with primary tumours, suggesting accessibility for T cells, could imply that osteosarcoma patients with metastatic disease may benefit from T-cell-based immunotherapy.

Electronic supplementary material

The online version of this article (doi:10.1007/s00262-016-1925-3) contains supplementary material, which is available to authorized users.

High nuclear expression of proteasome activator complex subunit 1 predicts poor survival in soft tissue leiomyosarcomas

Background

Previous studies on high grade sarcomas using mass spectrometry imaging showed proteasome activator complex subunit 1 (PSME1) to be associated with poor survival in soft tissue sarcoma patients. PSME1 is involved in immunoproteasome assembly for generating tumor antigens presented by MHC class I molecules. In this study, we aimed to validate PSME1 as a prognostic biomarker in an independent and larger series of soft tissue sarcomas by immunohistochemistry.

Methods

Tissue microarrays containing leiomyosarcomas (n = 34), myxofibrosarcomas (n = 14), undifferentiated pleomorphic sarcomas (n = 15), undifferentiated spindle cell sarcomas (n = 4), pleomorphic liposarcomas (n = 4), pleomorphic rhabdomyosarcomas (n = 2), and uterine leiomyomas (n = 7) were analyzed for protein expression of PSME1 using immunohistochemistry. Survival times were compared between high and low expression groups using Kaplan–Meier analysis. Cox regression models as multivariate analysis were performed to evaluate whether the associations were independent of other important clinical covariates.

Results

PSME1 expression was variable among soft tissue sarcomas. In leiomyosarcomas, high expression was associated with overall poor survival (p = 0.034), decreased metastasis-free survival (p = 0.002) and lower event-free survival (p = 0.007). Using multivariate analysis, the association between PSME1 expression and metastasis-free survival was still significant (p = 0.025) and independent of the histological grade.

Conclusions

High expression of PSME1 is associated with poor metastasis-free survival in soft tissue leiomyosarcoma patients, and might be used as an independent prognostic biomarker.

Electronic supplementary material

The online version of this article (doi:10.1186/s13569-016-0057-z) contains supplementary material, which is available to authorized users.

Analysis of PD-L1, T-cell infiltrate and HLA expression in chondrosarcoma indicates potential for response to immunotherapy specifically in the dedifferentiated subtype

Therapies targeting the programmed cell death 1 (PD-1) or its ligand (PD-L1) promote antitumor T-cell activity, leading to unprecedented long-lasting tumor responses in some advanced cancers. Because of radiotherapy and chemotherapy resistance, no effective treatments have been defined for advanced chondrosarcomas. We here report an immunohistochemical analysis of PD-L1 expression in a large series of conventional, mesenchymal, clear cell and dedifferentiated chondrosarcomas using tissue microarrays. In the PD-L1-positive tumors, we analyzed the immune microenvironment (T-cell and macrophage infiltration as well as HLA class I expression) using whole sections. PD-L1 expression was absent in conventional (n=119), mesenchymal (n=19) and clear cell (n=20) chondrosarcomas. Forty-one percent (9 of the 22) of dedifferentiated chondrosarcomas displayed PD-L1 positivity. These results were confirmed in an independent cohort using whole tissue sections of dedifferentiated chondrosarcomas in which PD-L1 expression was detected in 52% (11 of the 21) of cases. PD-L1 expression was exclusively found in the dedifferentiated component and expression positively correlated with other immune parameters such as high number of tumor-infiltrating lymphocytes (P=0.014) and positive HLA class I expression (P=0.024) but not with patient overall survival (P=0.22). The presence of PD-L1 expression in association with immune-infiltrating cells and HLA class I expression in nearly 50% of the dedifferentiated chondrosarcomas provides rationale for including these patients in clinical trials with PD-1/PD-L1-targeted therapies.

Evolution of Dermatofibrosarcoma Protuberans to DFSP-Derived Fibrosarcoma: An Event Marked by Epithelial-Mesenchymal Transition-like Process and 22q Loss

Dermatofibrosarcoma protuberans (DFSP) is a rare and indolent cutaneous sarcoma. At times, a fibrosarcomatous transformation marked by a more aggressive clinical behavior may be present. We investigated the natural history and the molecular bases of progression from classic DFSP to the fibrosarcomatous form (FS-DFSP), looking, retrospectively, at the outcome of all patients affected by primary DFSP treated at our institution from 1993 to 2012 and analyzing the molecular profile of 5 DFSPs and 5 FS-DFSPs by an integrated genomics approach (whole transcriptome sequencing, copy number analysis, FISH, qRT-PCR, IHC). The presence of fibrosarcomatous features was identified in 20 (7.6%) patients out of 263 DFSP. All cases were treated with macroscopic complete surgery. A local relapse occurred in 4 of 23 patients who received a microscopic marginal surgery (2 classic DFSP, 2 FS-DFSP), while metastasis affected 2 patients, both FS-DFSP (10% of FS-DFSP), being the first event. DFSP evolution to FS-DFSP was paralleled by a transcriptional reprogramming. The recurrent loss of chromosome 22q appeared to contribute to this phenomenon by promoting the expression of epigenetic regulators, such as EZH2. Loss of the p16/CDKN2A/INK4A locus at 9p was also observed in two FS-DFSP metastatic cases.

IMPLICATIONS

FS-DFSP is a rare subgroup among DFSP, with a 10% metastatic risk, that was independent from local recurrence and that was not observed in DFSP, that were all cured by wide surgery. Chromosome 22q deletion might play a role in FS-DFSP, and p16 loss may convey a poor outcome. EZH2 dysregulation was also found and represents a druggable target. Mol Cancer Res; 14(9); 820-9. ©2016 AACR.