Sarcoma Metastasis Research Articles

Brain metastases revealing primary pulmonary soft part sarcoma

Abstract Alveolar soft part sarcoma (ASPS) is a rare mesenchymal soft-tissue tumour. It commonly arises in the lower extremities in adults and the head and neck in children. Primary pulmonary involvement, without evidence of soft tissue tumour elsewhere, is very rare. We present the seventh case ever reported in the literature of primary ASPS of the lung, which was revealed by brain metastases in a 28-year-old male patient. The parietal brain tumour was resected. The radiological and histological study led to the diagnosis: metastasis of an alveolar sarcoma. The patient then had brain radiotherapy and chemotherapy. Using this case as a starting point, we reviewed the characteristics and the main therapeutic options in these uncommon neoplasms.

Determination of Optical Properties and Photodynamic Threshold of Lung Tissue for Treatment Planning of In Vivo Lung Perfusion Assisted Photodynamic Therapy

BackgroundIsolated lung metastases in sarcoma and colorectal cancer patients are inadequately treated with current standard therapies. In Vivo Lung Perfusion, a novel platform, could overcome limitations to photodynamic therapy treatment volumes by using low cellular perfusate, removing blood, theoretically allowing greater light penetration. To develop personalized photodynamic therapy protocols requires in silico light propagation simulations based on optical properties and maximal permissible photodynamic threshold dose of lung tissue. This study presents quantification of optical properties for two perfusates and the photodynamic threshold for 5-ALA and Chlorin e6. MethodsPorcine and human lungs were placed on Ex Vivo Lung Perfusion, and perfused with acellular solution or blood. Isotropic diffusers were placed within bronchi and on lung surface for light transmission measurements, from which absorption and light scattering properties were calculated at multiple wavelengths. Separately, pigs were injected with 5-ALA or Chlorin e6, and lung tissue was irradiated at increasing doses. Resultant lesion sizes were measured by CT and histology to quantify the photodynamic threshold. ResultsLow cellular perfusate reduced the tissue absorption coefficient significantly, increasing penetration depth of light by 3.3 mm and treatment volumes 3-fold. The photodynamic threshold for lung exposed to 5-ALA was consistent with other malignancies. Chlorin e6 levels were undetectable in lung tissue and did not demonstrate photodynamic-induced necrosis. ConclusionsLight penetration with low cellular perfusate is significantly greater and could enable treatments for diffuse disease. This data aids photodynamic treatment planning and will guide clinical translation of photodynamic therapy protocols in the lung, especially during lung perfusion.

Proteomic Screens for Suppressors of Anoikis Identify IL1RAP as a Promising Surface Target in Ewing Sarcoma.

Cancer cells must overcome anoikis (detachment-induced death) to successfully metastasize. Using proteomic screens, we found that distinct oncoproteins upregulate IL1 receptor accessory protein (IL1RAP) to suppress anoikis. IL1RAP is directly induced by oncogenic fusions of Ewing sarcoma, a highly metastatic childhood sarcoma. IL1RAP inactivation triggers anoikis and impedes metastatic dissemination of Ewing sarcoma cells. Mechanistically, IL1RAP binds the cell-surface system Xc - transporter to enhance exogenous cystine uptake, thereby replenishing cysteine and the glutathione antioxidant. Under cystine depletion, IL1RAP induces cystathionine gamma lyase (CTH) to activate the transsulfuration pathway for de novo cysteine synthesis. Therefore, IL1RAP maintains cyst(e)ine and glutathione pools, which are vital for redox homeostasis and anoikis resistance. IL1RAP is minimally expressed in pediatric and adult normal tissues, and human anti-IL1RAP antibodies induce potent antibody-dependent cellular cytotoxicity of Ewing sarcoma cells. Therefore, we define IL1RAP as a new cell-surface target in Ewing sarcoma, which is potentially exploitable for immunotherapy. SIGNIFICANCE: Here, we identify cell-surface protein IL1RAP as a key driver of metastasis in Ewing sarcoma, a highly aggressive childhood sarcoma. Minimal expression in pediatric and adult normal tissues nominates IL1RAP as a promising target for immunotherapy.See related commentary by Yoon and DeNicola, p. 2679.This article is highlighted in the In This Issue feature, p. 2659.

Role of lymphadenectomy for apparent early stage uterine sarcoma; a comprehensive analysis of the National Cancer Database

ObjectiveInvestigate the role of lymphadenectomy for patients with apparent stage I uterine sarcoma. MethodsThe National Cancer Database was accessed and patients without a history of another tumor diagnosed between 2004 and 2015 with an apparent early stage leiomyosarcoma, adenosarcoma, low-grade endometrial stromal and high-grade endometrial stromal/undifferentiated sarcoma who underwent hysterectomy with or without lymphadenectomy were identified. Overall survival was assessed after stratification by histology with the log-rank test while Cox models were constructed to control for confounders. ResultsA total of 6412 patients with apparent early stage uterine sarcoma who underwent hysterectomy were identified; 2820 (44%) underwent lymphadenectomy. Rate of lymph node metastasis was 3.4% (42/1250) for patients with leiomyosarcoma, 2.3% (19/826) for those with adenosarcoma, 4.5% (21/463) for patients with low-grade endometrial stromal sarcoma and 7.9% (22/280) for those with high-grade endometrial stromal/undifferentiated sarcoma, p < 0.001. After controlling for confounders lymphadenectomy was not associated with better survival for patients with adenosarcoma (HR: 0.92, 95% CI: 0.73, 1.17), or low-grade endometrial stromal sarcoma (HR: 1.17, 95% CI: 0.73, 1.87). Patients with leiomyosarcoma who underwent lymphadenectomy had worse survival (HR: 1.15, 95% CI: 1.03, 1.28). Patients with high-grade endometrial stromal/undifferentiated sarcoma who underwent lymphadenectomy had better survival (HR: 0.66, 95% CI: 0.48, 0.89). ConclusionsIncidence of lymph node metastasis in apparent early stage uterine sarcoma is rare while the performance of lymphadenectomy was not associated with a clear survival benefit for all histologic subtypes except high-grade endometrial stromal/undifferentiated sarcoma.

Late Local Recurrence and Metastasis in Soft Tissue Sarcoma of the Extremities and Trunk Wall: Better Outcome After Treatment of Late Events Compared with Early

BackgroundApproximately 80% of soft tissue sarcoma (STS) recurrences, local and metastatic disease, are diagnosed within the first 3 years after primary diagnosis and treatment. Recurrences, however, can present after a longer period of remission. Our goal was to identify factors that may predict the risk of late recurrence.MethodsWe identified 677 patients with STS of the extremities and trunk wall from a population-based sarcoma register. Of these, 377 patients were alive and event-free at 3 years and were included for analysis of possible risk factors for late recurrence.ResultsFifty-five of 377 (15%) patients developed late recurrence: 23 local recurrence, 21 metastasis, and 11 both manifestations. With R0 wide surgical margin as reference, R0 marginal (hazard ratio [HR] 2.6; p = 0.02) and R1 (HR 5.0; p = 0.005) margins were risk factors for late local recurrence. Malignancy grade (HR 8.3; p = 0.04) and R0 marginal surgical margin (HR 2.3; p = 0.04) were risk factors for late metastasis. We could not find a statistically significant correlation of late recurrence with many of the generally known risk factors for local recurrence and metastasis in STS. Outcome after treatment of late recurrences was better compared with outcome after treatment of early events.ConclusionsLate recurrences, albeit relatively rare, do occur. Outcome after treatment was good compared with outcome after early events. Long surveillance of all patients with high-grade STS, especially if R0 wide surgical margin is not achieved in the primary treatment, appear to be well justified.

Sensitivity and Resistance of Oncogenic RAS-Driven Tumors to Dual MEK and ERK Inhibition.

Simple SummaryMutations in RAS-family genes frequently cause different types of human cancers. Inhibitors of the MEK (mitogen-activated protein kinase) and ERK (extracellular signal-regulated kinase) protein kinases that function downstream of RAS proteins have shown some clinical benefits when used for the treatment of these cancers, but drug resistance frequently emerges. Here we show that combined treatment with MEK and ERK inhibitors blocks the emergence of resistance to either drug alone. However, if cancer cells have already developed resistance to MEK inhibitors or to ERK inhibitors, the combined therapy is frequently ineffective. These findings imply that these inhibitors should be used together for cancer therapy. We also show that drug resistance involves complex patterns of rewiring of cellular kinase signaling networks that do not overlap between each different cancer cell line. Nonetheless, we show that MAP4K4 is required for efficient cell proliferation in several different MEK/ERK inhibitor resistant cancer cell lines, uncovering a potential new therapeutic target.Oncogenic mutations in RAS family genes arise frequently in metastatic human cancers. Here we developed new mouse and cellular models of oncogenic HrasG12V-driven undifferentiated pleomorphic sarcoma metastasis and of KrasG12D-driven pancreatic ductal adenocarcinoma metastasis. Through analyses of these cells and of human oncogenic KRAS-, NRAS- and BRAF-driven cancer cell lines we identified that resistance to single MEK inhibitor and ERK inhibitor treatments arise rapidly but combination therapy completely blocks the emergence of resistance. The prior evolution of resistance to either single agent frequently leads to resistance to dual treatment. Dual MEK inhibitor plus ERK inhibitor therapy shows anti-tumor efficacy in an HrasG12V-driven autochthonous sarcoma model but features of drug resistance in vivo were also evident. Array-based kinome activity profiling revealed an absence of common patterns of signaling rewiring in single or double MEK and ERK inhibitor resistant cells, showing that the development of resistance to downstream signaling inhibition in oncogenic RAS-driven tumors represents a heterogeneous process. Nonetheless, in some single and double MEK and ERK inhibitor resistant cell lines we identified newly acquired drug sensitivities. These may represent additional therapeutic targets in oncogenic RAS-driven tumors and provide general proof-of-principle that therapeutic vulnerabilities of drug resistant cells can be identified.

Benefit of surgical resection of distant metastasis in soft tissue sarcoma: a systematic review.

The aim of this systematic review was to evaluate the efficacy of metastasectomy for patients with advanced soft tissue sarcoma and to develop a recommendation outlining clinical guidelines for soft tissue sarcoma. We searched the pertinent literature from January 1985 to December 2017. Two reviewers evaluated and screened the literature independently for eligibility and extracted data. We evaluated the quality of body of evidence and made a recommendation according to the Grading of Recommendations Development and Evaluation methodology. Among 244 identified studies, only 10 were finally included in this review and no randomized controlled trial reports were present. The median survival period after metastasectomy ranged from 9.6 to 39.6months, and the 5-year survival rate ranged from 8 to 52%. The complication rate ranged from 7.3 to 25%, and the perioperative mortality rate was 0-1%. The guidelines committee proposed 'Metastasectomy can be offered for malignant soft tissue tumours with distant metastases'. This recommendation gained 100% consensus among the members of the guidelines group. Although the level of evidence is very low, many retrospective studies support a clinical advantage for metastasectomy, and surgical indications should be carefully considered for patients with metastasis from soft tissue sarcoma. Metastasectomy is an option for patients with metastasis and should be done only if it can be performed safely and if potential advantages outweigh disadvantages.

Recurrent spontaneous pneumothorax due to pulmonary cystic metastasis of epithelioid sarcoma

Recurrent spontaneous pneumothorax due to pulmonary cystic metastasis of epithelioid sarcoma

A Population-based Analysis of Lymph Node Metastasis in Extremity Soft Tissue Sarcoma: An Update

BackgroundSoft tissue sarcomas (STSs) are mesenchymal tumors that may rarely metastasize to lymph nodes. This investigation sought to evaluate regional lymph node metastasis (RLNM) in extremity STS using a national cohort. Materials and methodsThis study was a retrospective review of the Surveillance, Epidemiology, and End Results database from 1975 to 2016. A Cox proportional hazards model was used to identify prognostic factors associated with disease-specific survival (DSS). ResultsRLNM was present in 3.7% (n = 547) of extremity STS. The rate of RLNM was highest in rhabdomyosarcoma (26.7%), clear cell sarcoma (18.8%), epithelioid sarcoma (14.5%), angiosarcoma (8.1%), spindle cell sarcoma (5.0%), and synovial sarcoma (3.2%). The 5-year DSS probability without RLNM was 69% (standard error: 1.3%) compared to 26% (standard error: 3.6%) with RLNM (P < 0.001). For the historically high-risk extremity STS, advanced age (hazard ratio (HR), 1.036; 95% confidence interval (CI), 1.0-1.04; P < 0.001), higher grade tumors (HR, 1.979; 95% CI, 1.3-3.0; P < 0.001), tumor size greater than 10 cm (HR, 1.892; 95% CI, 1.3-2.7; P < 0.001), primary site surgery (HR, 0.529; 95% CI, 0.3-0.8; P = 0.006), distant metastasis (HR, 4.585; 95% CI, 3.0-6.8; P < 0.001), and RLNM (HR, 2.153; 95% CI, 1.3-3.5; P = 0.003) were each independent disease-specific prognostic factors. ConclusionsThe prognosis of RLNM in historically high-risk extremity STS is poor with a 5-year DSS of 26%. These data support a staging system of STS inclusive of nodal involvement and contribute to the growing body of evidence that characterizes the rates of RLNM in STS.

Immunological status of peripheral blood is associated with prognosis in patients with bone and soft-tissue sarcoma.

Immune-checkpoint inhibitors have shown promising antitumor effects against certain types of cancer. However, specific immune-checkpoint inhibitors for patients with sarcoma have yet to be identified, whereas the immunological status of peripheral blood in patients with bone sarcoma and soft-tissue sarcoma (STS) remains unknown. In addition, it is unclear whether the immunological status from the peripheral blood could be used as a prognostic indicator. Therefore, the present study aimed to clarify the immunological status of peripheral blood samples derived from patients with bone sarcoma and STS. Immune monitoring was performed using the peripheral blood samples of 61 patients with no metastasis of high-grade sarcoma. A total of 25 patients with metastatic sarcoma were used for comparison. A total of 41 immune cell subsets were analyzed using multicolor-flow cytometry. The patients that did not have metastasis demonstrated higher quantities of monocytic myeloid-derived suppressor cells (M-MDSCs) and T cell immunoglobulin and mucin domain-3 (Tim-3)+ CD8+ T cells, which were significantly associated with poor disease-free survival (DFS) time, while higher quantities of NKG2D+ CD8+ T cells were significantly associated with improved DFS time. Multivariate Cox regression analysis demonstrated that the number of Tim-3+ CD8+ T cells was associated with lower DFS time. A significant association was also found between the number of M-MDSCs and progression-free survival (PFS) time in patients with metastasis. The results suggested the occurrence of immune surveillance, which indicated that the host immune reaction against cancer existed in patients with bone sarcoma and STS. Notably, a high number of M-MDSCs was associated with both DFS and PFS time, suggesting a strong prognostic value. The data suggested that the immune status of peripheral blood was associated with the prognosis in patients with sarcoma, as previously reported in patients with other cancer types. In summary, the results may assist with the development of novel strategies for sarcoma treatment, based on the use of biomarkers or immunotherapy.

Targeting Lymphotoxin Beta and Paired Box 5: a potential therapeutic strategy for soft tissue sarcoma metastasis

BackgroundSoft tissue sarcomas (STS) has a high rate of early metastasis. In this study, we aimed to uncover the potential metastasis mechanisms and related signaling pathways in STS with differentially expressed genes and tumor-infiltrating cells.MethodsRNA-sequencing (RNA-seq) of 261 STS samples downloaded from the Cancer Genome Atlas (TCGA) database were used to identify metastasis-related differentially expressed immune genes and transcription factors (TFs), whose relationship was constructed by Pearson correlation analysis. Metastasis-related prediction model was established based on the most significant immune genes. CIBERSORT algorithm was performed to identify significant immune cells co-expressed with key immune genes. The GSVA and GSEA were performed to identify prognosis-related KEGG pathways. Ultimately, we used the Pearson correlation analysis to explore the relationship among immune genes, immune cells, and KEGG pathways. Additionally, key genes and regulatory mechanisms were validated by single-cell RNA sequencing and ChIP sequencing data.ResultsA total of 204 immune genes and 12 TFs, were identified. The prediction model achieved a satisfactory effectiveness in distant metastasis with the Area Under Curve (AUC) of 0.808. LTB was significantly correlated with PAX5 (P < 0.001, R = 0.829) and hematopoietic cell lineage pathway (P < 0.001, R = 0.375). The transcriptional regulatory pattern between PAX5 and LTB was validated by ChIP sequencing data.ConclusionsWe hypothesized that down-regulated LTB (immune gene) modulated by PAX5 (TF) in STSs may have the capability of inducing cancer cell metastasis in patients with STS.

Outcomes of brain metastasis in high-grade bone and soft tissue sarcoma: An analysis of clinicopathological characteristics and survival data.

Brain metastases in sarcoma are exceedingly rare, with few published series documenting ranges from 1% to 8%. This study investigated the outcomes of sarcoma patients with brain metastases using a population-based analysis. This was a retrospective review of 5933 patients with high-grade sarcoma identified from the Surveillance, Epidemiology, and End Results database between 2010 and 2015. Of the eligible 5933 patients, 0.7% (n = 44) had brain metastasis. Kaplan–Meier was used to estimate survival and follow-up (reverse Kaplan–Meier), and a multivariable Cox proportional hazards model analyzed prognostic factors of disease-free survival (DFS). Median (IQR) follow-up of all eligible patients was 28 months (12; 47). Patients who developed brain metastasis had a higher proportion of N1 stage disease (p < 0.001), as well as synchronous metastasis to bones, liver, and lungs compared to those without brain metastasis (all p < 0.001). The median (IQR) DFS with brain metastasis was 6 months (2; 12), and survival with brain metastasis was significantly worse than DFS in patients without brain metastasis (p < 0.001). Among those with brain metastasis only, there was no difference in DFS with respect to sex, race, primary tumor origin, T stage or N stage disease, synchronous metastasis to bone, liver or lung, nor with respect to chemotherapy or radiation for treatment of the primary tumor (all p > 0.05). For sarcoma patients with brain metastasis, the outcomes are poor and do not appear to differ by clinicopathologic factors. However, patients with certain histologies and synchronous metastases may warrant more frequent surveillance as there was an association of brain metastasis with these factors.

Osteogenic Sarcoma Presenting with Skip, Lymph Nodal, Pulmonary, Pleural Metastases and Malignant Effusion: An Unusual Appearance on Bone Scan.

Osteogenic sarcoma is an aggressive malignant bone tumor arising from primitive mesenchymal bone-forming cells. Ossification is the characteristic feature of the metastases in osteosarcoma which aids their detection on 99mTc-MDP bone scintigraphy. Although lung is the most common site of metastasis in osteogenic sarcoma, pleural involvement with effusion and skip metastases are rare. Herein, we report a case of osteogenic sarcoma of distal femur with diffuse calcified pleural thickening leading to malignant pleural effusion, calcified lung, lymph node, and bone metastases illustrated on bone scan.

Should metastatic lymph nodes be considered at the same clinical stage as distant metastasis in soft tissue sarcomas?

IntroductionLymph node metastasis (LNM) in soft tissue sarcomas (STS) are uncommon, occurring in only 3% – 5% of all sarcomas, and are classified as Stage IV, along with distant metastasis (DM). This paper compares the prognosis of patients with lymphatic and DM, in extremity STS (eSTS). MethodsA retrospective study was carried out in a high-volume sarcoma center; 853 patients with eSTS sarcomas were identified and classified from January 1, 1997 to December 31, 2017. Cases with pathological confirmation of LNM were included. Five-year survival rates were analyzed using the Kaplan-Meier method and the Cox proportional hazards model. ResultsLNM was present in 46 of the cases (5.4%), with an overall survival of 21 months (95% confidence interval [CI], 16.7 – 25.2), compared to 18 months (95% confidence interval [CI], 14.2 – 21.7) in those with only DM. Median recurrence-free survival was 21 months (95% confidence interval [CI], 19.7 – 22.4), vs. 20 months (95% confidence interval [CI], 16.2– 23.7), respectively. LNM only and DM only had also a similar OS of 21 months (95% CI 16.7–25.2) vs 18 months (95% CI 14.2–21.7. N1M1 cases had the worse median OS with 15 months (95% confidence interval [CI], 10.9–19.7) ConclusionsOverall survival and recurrence free survival in patients with lymph node disease and metastatic disease are similar. However prognosis is worse in N1M1. Use of systemic treatment in patients with LNM is not as common as in metastatic cases, this difference in treatment and the fact that prognosis is similar suggests that both biological behavior and effect of treatment have been underestimated. A subclassification of clinical stage IV might be the next step.

Delayed Initiation of Treatment Is Associated With Metastasis of Soft-tissue Sarcoma

The delayed initiation of treatment is associated with poor clinical outcomes in patients with malignancies. However, few previous studies have investigated prognostic factors, including the delayed initiation of treatment, in soft-tissue sarcoma. One hundred and fifty-three patients with soft-tissue sarcoma were enrolled. Univariate and multivariate analyses were performed to identify factors predicting metastasis, including factors that delay the initiation of treatment. The multivariate analysis revealed that high histological grade (p<0.01), tumor located in the trunk (p=0.04), >5-month delay from symptom initiation to consultation of general practitioner (p=0.02), and >29-day delay in referral to a specialized hospital by general practitioners (p=0.03) were independently associated with metastasis of soft tissue sarcoma. Early consultation of a general practitioner and early referral to a specialized hospital might be essential for preventing metastasis of soft-tissue sarcoma.

Assessing immune infiltration and the tumor microenvironment for the diagnosis and prognosis of sarcoma

BackgroundSarcomas, cancers originating from mesenchymal cells, are comprehensive tumors with poor prognoses, yet their tumorigenic mechanisms are largely unknown. In this study, we characterize infiltrating immune cells and analyze immune scores to identify the molecular mechanism of immunologic response to sarcomas.MethodThe “CIBERSORT” algorithm was used to calculate the amount of L22 immune cell infiltration in sarcomas. Then, the “ESTIMATE” algorithm was used to assess the “Estimate,” “Immune,” and “Stromal” scores. Weighted gene co-expression network analysis (WGCNA) was utilized to identify the significant module related to the immune therapeutic target. Gene ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed using the “clusterProfiler” package in R for annotation and visualization.ResultsMacrophages were the most common immune cells infiltrating sarcomas. The number of CD8 T cells was negatively associated with that of M0 and M2 macrophages, and positively associated with M macrophages in sarcomas samples. The clinical parameters (disease type, gender) significantly increased with higher Estimate, Immune, and Stromal scores, and with a better prognosis. The blue module was significantly associated with CD8 T cells. Functional enrichment analysis showed that the blue module was mainly involved in chemokine signaling and the PI3K-Akt signaling pathway. CD48, P2RY10 and RASAL3 were identified and validated at the protein level.ConclusionBased on the immune cell infiltration and immune microenvironment, three key genes were identified, thus presenting novel molecular mechanisms of sarcoma metastasis.

Hepatectomy for Breast Cancer Metastasis and Sarcoma are more likely to have Adverse Outcomes than Hepatectomy for Primary Hepatocellular Cancer or for Colorectal Metastasis

Outcomes for hepatectomy for breast cancer metastasis and sarcomatous disease processes are not well defined in literature. We sought to use a national database to identify outcomes in these patients compared to subset of patients more well studied in literature - primary Hepatocellular cancer patients and patients with colorectal metastasis. We identified patients undergoing major hepatectomy (≥ 3 segments) for primary hepatocellular cancer (HCC), sarcoma metastasis, breast cancer metastasis, and colorectal metastasis using NSQIP database. The Primary outcome measure was 30-day mortality. Secondary outcome measures were 30-day readmission and complication rates. A total of 5580 patients underwent major hepatectomy during the study period. Patients who underwent hepatectomy for breast cancer metastasis had higher incidence of in-hospital complications (37%) compared to sarcoma (29%), colon (26%), and HCC patients (24%) and 30-days readmission rate (37% vs. 29% - sarcoma vs. 26% - colon vs. 25% HCC). There was no difference in 30-days mortality among the groups. Patients undergoing major hepatectomies for breast cancer metastasis and sarcoma are more likely to have adverse outcomes than compared to their counterparts. This difference highlights the lack of experience in managing breast cancer and sarcoma with metastatic disease to the liver. This also highlights the difference in tumor biology among all the lesions we studied. An extensive discussion should take place when dealing with breast and sarcoma lesions in the liver because of these outcomes.

A novel HDGF-ALCAM axis promotes the metastasis of Ewing sarcoma via regulating the GTPases signaling pathway.

Ewing sarcoma (ES) is a type of highly aggressive pediatric tumor in bones and soft tissues and its metastatic spread remains the most powerful predictor of poor outcome. We previously identified that the transcription factor hepatoma-derived growth factor (HDGF) promotes ES tumorigenesis. However, the mechanisms underlying ES metastasis remain unclear. Here, we show that HDGF drives ES metastasis in vitro and in vivo, and HDGF reduces metastasis-free survival (MFS) in two independent large cohorts of human ES patients. Integrative analyses of HDGF ChIP-seq and gene expression profiling in ES cells reveal that HDGF regulates multiple metastasis-associated genes, among which activated leukocyte cell adhesion molecule (ALCAM) emerges as a major HDGF target and a novel metastasis-suppressor in ES. HDGF down-regulates ALCAM, induces expression and activation of the downstream effectors Rho-GTPase Rac1 and Cdc42, and promotes actin cytoskeleton remodeling and cell-matrix adhesion. In addition, repression of ALCAM and activation of Rac1 and Cdc42 are required for the pro-metastatic functions of HDGF in vitro. Moreover, analyses in murine models with ES tumor orthotopic implantation and experimental metastasis, as well as in human ES samples, demonstrate the associations among HDGF, ALCAM, and GTPases expression levels. Furthermore, high HDGF/low ALCAM expression define a subgroup of patients harboring the worst MFS. These findings suggest that the HDGF/ALCAM/GTPases axis represents a promising therapeutic target for limiting ES metastasis.

KDM5A and PHF2 positively control expression of pro-metastatic genes repressed by EWS/Fli1, and promote growth and metastatic properties in Ewing sarcoma.

Ewing sarcoma is an aggressive malignant neoplasm with high propensity for metastasis and poor clinical outcomes. The EWS/Fli1 oncofusion is the disease driver in > 90% of cases, but presents a difficult therapeutic target. Moreover, EWS/Fli1 plays a complex role in disease progression, with inhibitory effects on critical steps of metastasis. Like many other pediatric cancers, Ewing sarcoma is a disease marked by epigenetic dysregulation. Epigenetic mechanisms present alternative targeting opportunities, but their contributions to Ewing sarcoma metastasis and disease progression remain poorly understood. Here, we show that the epigenetic regulators KDM5A and PHF2 promote growth and metastatic properties in Ewing sarcoma, and, strikingly, activate expression many pro-metastatic genes repressed by EWS/Fli1. These genes include L1CAM, which is associated with adverse outcomes in Ewing sarcoma, and promotes migratory and invasive properties. KDM5A and PHF2 retain their growth promoting effects in more metastatically potent EWS/Fli1low cells, and PHF2 promotes both invasion and L1CAM expression in this cell population. Furthermore, KDM5A and PHF2 each contribute to the increased metastatic potency of EWS/Fli1low cells in vivo. Together, these studies identify KDM5A and PHF2 as novel disease-promoting factors, and potential new targets, in Ewing sarcoma, including the more metastatically potent EWS/Fli1low cell population.

CIC Is a Mediator of the ERK1/2-DUSP6 Negative Feedback Loop.

SummaryDUSP6 functions as an important negative feedback component of the MAPK/ERK signaling pathway. Although DUSP6 expression is tightly regulated by ERK1/2 signaling, the molecular mechanism of this regulation remains partially understood. In this work, we show that the transcriptional repressor CIC functions downstream of the ERK1/2 signaling to negatively regulate DUSP6 expression. CIC directly represses DUSP6 transcription by binding to three cis-regulatory elements (CREs) in DUSP6 promoter. p90RSK, a downstream target of ERK1/2, phosphorylates CIC at S173 and S301 sites, which creates a 14-3-3 recognition motif, resulting in 14-3-3-mediated nuclear export of CIC and derepression of DUSP6. Finally, we demonstrate that the oncogenic CIC-DUX4 fusion protein acts as a transcriptional activator of DUSP6 and its nuclear/cytoplasmic distribution remains regulated by ERK1/2 signaling. These results complete an ERK1/2/p90RSK/CIC/DUSP6 negative feedback circuit and elucidate the molecular mechanism of how RTK/MAPK signaling harnesses the transcriptional repressor activity of CIC in mammalian cells.