Afatinib Is a New Therapeutic Approach in Chordoma with a Unique Ability to Target EGFR and Brachyury

Non-kinase off-target inhibitory activities of clinically-relevant kinase inhibitors

Protein kinases are responsible for a myriad of cellular functions, such as cell cycle, apoptosis, and proliferation. Because of this, kinases make excellent targets for therapeutics. During the process to identify clinical kinase inhibitor candidates, kinase selectivity profiles of lead inhibitors are typically obtained. Such kinome selectivity screening could identify crucial kinase anti-targets that might contribute to drug toxicity and/or reveal additional kinase targets that potentially contribute to the efficacy of the compound via kinase polypharmacology. In addition to kinome panel screening, practitioners also obtain the inhibition profiles of a few non-kinase targets, such as ion-channels and select GPCR targets to identify compounds that might possess potential liabilities. Often ignored is the possibility that identified kinase inhibitors might also inhibit or bind to the other proteins (greater than 20,000) in the cell that are not kinases, which may be relevant to toxicity or even additional mode of drug action. This review highlights various inhibitors, which have been approved by the FDA or are currently undergoing clinical trials, that also inhibit other non-kinase targets. The binding poses of the drugs in the binding sites of the target kinases and off-targets are analyzed to understand if the same features of the compounds are critical for the polypharmacology.

Development of a Small Molecule Downmodulator for the Transcription Factor Brachyury

Brachyury is an oncogenic transcription factor whose overexpression drives chordoma growth. The downmodulation of brachyury in chordoma cells has demonstrated therapeutic potential, however, as a transcription factor it is classically deemed "undruggable". Given that direct pharmacological intervention against brachyury has proven difficult, attempts at intervention have instead targeted upstream kinases. Recently, afatinib, an FDA-approved kinase inhibitor, has been shown to modulate brachyury levels in multiple chordoma cell lines. Herein, we use afatinib as a lead to undertake a structure-based drug design approach, aided by mass-spectrometry and X-ray crystallography, to develop DHC-156, a small molecule that more selectively binds brachyury and downmodulates it as potently as afatinib. We eliminated kinase-inhibition from this novel scaffold while demonstrating that DHC-156 induces the post-translational downmodulation of brachyury that results in an irreversible impairment of chordoma tumor cell growth. In doing so, we demonstrate the feasibility of direct brachyury modulation, which may further be developed into more potent tool compounds and therapies.

Integrated Molecular and Histological Insights for Targeted Therapies in Mesenchymal Sinonasal Tract Tumors

PURPOSE OF REVIEW

This review aims to provide a comprehensive overview of mesenchymal sinonasal tract tumors (STTs), a distinct subset of STTs. Despite their rarity, mesenchymal STTs represent a unique clinical challenge, characterized by their rarity, often slow progression, and frequently subtle or overlooked symptoms. The complex anatomy of the sinonasal area, which includes critical structures such as the orbit, brain, and cranial nerves, further complicates surgical treatment options. This underscores an urgent need for more advanced and specialized therapeutic approaches.

RECENT FINDINGS

Advancements in molecular diagnostics, particularly in next-generation sequencing, have significantly enhanced our understanding of STTs. Consequently, the World Health Organization has updated its tumor classification to better reflect the distinct histological and molecular profiles of these tumors, as well as to categorize mesenchymal STTs with greater accuracy. The growing understanding of the molecular characteristics of mesenchymal STTs opens new possibilities for targeted therapeutic interventions, marking a significant shift in treatment paradigms. This review article concentrates on mesenchymal STTs, specifically addressing sinonasal tract angiofibroma, sinonasal glomangiopericytoma, biphenotypic sinonasal sarcoma, and skull base chordoma. These entities are marked by unique histopathological and molecular features, which challenge conventional treatment approaches and simultaneously open avenues for novel targeted therapies. Our discussion is geared towards delineating the molecular underpinnings of mesenchymal STTs, with the objective of enhancing therapeutic strategies and addressing the existing shortcomings in the management of these intricate tumors.

Activation of Wnt Pathway Suppresses Growth of MUG-Chor1 Chordoma Cell Line

Chordoma as a malignant bone tumor, occurs along the axial skeleton and does not have an effective therapy. Brachyury, which is a crucial player for the formation of early embryonic notochord, is abundantly found in both sporadic and familial chordoma. During embryonic development, Brachyury expression was reported to be regulated by the Wnt pathway. The objective of the study is to investigate the role of Wnt signaling in a human chordoma cell line in terms of proliferation, survival, and invasiveness. We tried to elucidate the signaling events that regulate Chordoma cancer. In this regard, Wnt pathway was activated or inhibited using various strategies including small molecules, siRNA-based knockdown and overexpression applications. The results indicated the negative regulatory effect of Wnt signaling activity on proliferation and migration capacity of the chordoma cells. It was revealed that when GSK3β was inhibited, the Wnt pathway was activated and negatively regulated T/Bra expression. Activity of the Wnt pathway caused cell cycle arrest, reduced migration potential of the cells, and led to cell death. Therefore, the present study suggests that the Wnt pathway plays a key role in suppressing the proliferation and invasive characteristics of human chordoma cells and has a great potential as a therapeutic target in further clinical studies.

Bibliometric Insights in Advances of Chordoma: Global Trends and Research Development in the Last Decade

Chordoma is a rare tumor, but has a serious effect on the quality of life of patients. This study aims to assess the overall knowledge structure and trends in the development of chordoma research using a bibliometric analysis and visualization tool. Research datasets were acquired from the Web of Science. VOS viewer and CiteSpace visualization software were used to demonstrate collaborations and correlations. Annual trends in publications, distribution, H-index status, co-authorship status, and research hotspots were analyzed. A total of 1844 publications from 2012 to 2022 were included. The number of chordoma-related publications increased year by year. The United States contributed the most publications (717) and had the highest total citations (10130) and H-index (50), followed by China. The United States was also the country most frequently involved in international cooperation. The most productive organization involved in chordoma research was Massachusetts General Hospital. World Neurosurgery (114) published the most papers on chordoma. Hornicek FJ was the most productive author over the last decade (41). Initially, diagnosis and the location of onset captured the attention of the research society. Quality of life, risk factors, disability, minimally invasive surgical techniques, molecular targeted therapy, and radiotherapy technology are the research hotspots in recent years. Indeed, this study provides important insights into the overall landscape of chordoma research and also contributes to the further investigation of the international frontier of chordoma.

The KRAS signaling pathway's impact on the characteristics of pancreatic cancer cells

Pancreatic ductal adenocarcinoma (PDAC) is classified as a cancer with high metastasis so that its mortality rate is high and most of the patients could not survive longer than 5 years. RAS signaling participate in cellular processes, so it has a key role in PDAC.RAS activation is associated via three different signaling pathway including somatic oncogenic point mutations in KRAS, upstream signaling like EGFR, oncogenic activation of the downstream B-RAF molecule. Several targeted therapies have been developed against kinase effectors particularly those in the MAPK and PI3K (phosphoinositide 3-kinase)/mTOR signaling pathways and several inhibitors are undergoing clinical studies at the moment. However, because it is highly metastatic and frequently diagnosed at advanced disease stages, pancreatic cancer continues to be a challenging cancer to treat. This article will explore therapeutic approaches that focus on oncogenic KRAS signaling in pancreatic cancer and provide an updated synopsis of our knowledge of how mutant KRAS function in the illness.

Shedding light on emerging therapeutic targets for chordoma

INTRODUCTION

Despite encouraging advances in radiation and surgical treatment, chordomas remain resistant to chemotherapy and local recurrence is common. Although the primary mechanism of recurrence is local, metastatic disease occurs in a small subset of patients. Recurrence may also occur along the surgical trajectory if care is not taken to fully excise the open biopsy pathway. There is increasing morbidity with reoperation upon disease recurrence, and radiation is an option for cytoreduction in primary disease or for recurrent disease, although toxicity may be observed with high-dose therapies. Given these challenges, targeted chemotherapeutic agents for postoperative adjuvant treatment are needed.

AREAS COVERED

In this review, we summarize the genetic drivers of chordoma and the state of the current research in chordoma immunotherapy and epigenetics.

EXPERT OPINION

Chordoma is a heterogenous tumor that should be targeted from different angles and the study of its characteristics, from molecular to immunological to epigenetic, is necessary. Combining different approaches, such as studying noninvasive patient methylation patterns with tissue-based molecular and drug screening, can transform patient care by guiding treatment decisions based on prognostic mechanisms from different sources, while helping individualize surgical planning and treatment.

High-Throughput/High Content Imaging Screen Identifies Novel Small Molecule Inhibitors and Immunoproteasomes as Therapeutic Targets for Chordoma

Chordomas account for approximately 1-4% of all malignant bone tumors and 20% of primary tumors of the spinal column. It is a rare disease, with an incidence estimated to be approximately 1 per 1,000,000 people. The underlying causative mechanism of chordoma is unknown, which makes it challenging to treat. Chordomas have been linked to the T-box transcription factor T (TBXT) gene located on chromosome 6. The TBXT gene encodes a protein transcription factor TBXT, or brachyury homolog. Currently, there is no approved targeted therapy for chordoma. Here, we performed a small molecule screening to identify small chemical molecules and therapeutic targets for treating chordoma. We screened 3730 unique compounds and selected 50 potential hits. The top three hits were Ribociclib, Ingenol-3-angelate, and Duvelisib. Among the top 10 hits, we found a novel class of small molecules, including proteasomal inhibitors, as promising molecules that reduce the proliferation of human chordoma cells. Furthermore, we discovered that proteasomal subunits PSMB5 and PSMB8 are increased in human chordoma cell lines U-CH1 and U-CH2, confirming that the proteasome may serve as a molecular target whose specific inhibition may lead to better therapeutic strategies for chordoma.

Bibliometric analysis of the global research trends and hotspots in chordoma from 2000 to 2020

INTRODUCTION

Chordoma is formed from embryonic residues or ectopic chordae and locally aggressive or malignant tumors. We visually analyzed the research tendency and hotspot of chordoma.

METHODS

The bibliometric analysis was conducted from the Web of Science Core Collection database over the past two decades. The term and strategies were as follows: "TS = (chordoma) OR TS = (chordoblastoma) OR TS = (chordocarcinoma) OR TS = (chordoepithelioma) OR TS = (chordosarcoma) OR TS = (notochordoma). AND Language: English. AND Reference Type: Article OR Review". A total of 2,118 references were retrieved and used to make a visual analysis by VOSviewer 1.6.15.

RESULTS

The chordoma was on a steady rise and chordoma but remained the focus of scholars and organizations over the last two decades. The Chinese institutions and scholars lacked cooperation with their counterparts in other countries. The citations of documents and co-citation analysis of cited references suggested that M.L. McMaster, B.P. Walcott, P. Bergh, and S. Stacchiotti were leading researchers in this field of chordoma and their papers had been widely accepted and inspired recent researches. Keywords associated with recent chemotherapy, PD-1-related immunotherapy, and SMARCB1/integrase interactor 1 (INI1) in chordoma were a shortage of research and there may be more research ideas in the future by scholars. The research of chordoma will continue to be the hotspot.

CONCLUSIONS

Thus, explaining the molecular mechanism and potential role of transcriptional inhibition and immunologic responses to SMARCB1/INI1-negative poorly differentiated chordoma will be available for preclinical experiments and clinical trials and lead to new therapeutic opportunities for chordoma patients.

Emerging target discovery and drug repurposing opportunities in chordoma

The development of effective and personalized treatment options for patients with rare cancers like chordoma is hampered by numerous challenges. Biomarker-guided repurposing of therapies approved in other indications remains the fastest path to redefining the treatment paradigm, but chordoma's low mutation burden limits the impact of genomics in target discovery and precision oncology efforts. As our knowledge of oncogenic mechanisms across various malignancies has matured, it's become increasingly clear that numerous properties of tumors transcend their genomes - leading to new and uncharted frontiers of therapeutic opportunity. In this review, we discuss how the implementation of cutting-edge tools and approaches is opening new windows into chordoma's vulnerabilities. We also note how a convergence of emerging observations in chordoma and other cancers is leading to the identification and evaluation of new therapeutic hypotheses for this rare cancer.

Proteomics and phosphoproteomics of chordoma biopsies reveal alterations in multiple pathways and aberrant kinases activities

Background

Chordoma is a slow-growing but malignant subtype of bone sarcoma with relatively high recurrence rates and high resistance to chemotherapy. It is urgent to understand the underlying regulatory networks to determine more effective potential targets. Phosphorylative regulation is currently regarded as playing a significant role in tumorigenesis, and the use of tyrosine kinase inhibitors in clinical practice has yielded new promise for the treatment of a variety of sarcoma types.

Materials and methods

We performed comprehensive proteomic and phosphoproteomic analyses of chordoma using four-dimensional label-free liquid chromatography–tandem mass spectrometry (LC-MS/MS) and bioinformatics analysis. The potential aberrantly expressed kinases and their functions were validated using western blotting and CCK-8 assays.

Results

Compared with paired normal muscle tissues, 1,139 differentially expressed proteins (DEPs) and 776 differentially phosphorylated proteins (DPPs) were identified in chordoma tumor tissues. The developmentally significant Wnt-signaling pathway and oxidative phosphorylation were aberrant in chordoma. Moreover, we predicted three kinases (AURA, CDK9, and MOK) with elevated activity by kinase-pathway network analysis (KiPNA) and verified their increased expression levels. The knockdown of these kinases markedly suppressed chordoma cell growth, and this was also the case for cells treated with the CDK9 inhibitor AZD4573. We additionally examined 208 proteins whose expression and phosphorylation levels were synergetically altered.

Conclusions

We herein depicted the collective protein profiles of chordomas, providing insight into chordomagenesis and the potential development of new therapeutic targets.

Research hotspots and trends of chordoma: A bibliometric analysis

Background

Chordoma is a type of mesenchymal malignancy with a high recurrence rate and poor prognosis. Due to its rarity, the tumorigenic mechanism and optimal therapeutic strategy are not well known.

Methods

All relevant articles of chordoma research from 1 January 2000 to 26 April 2022 were obtained from Web of Science Core Collection database. Blibliometrix was used to acquire basic publication data. Visualization and data table of collaboration network, dynamic analysis, trend topics, thematic map, and factorial analysis were acquired using Blibliometrix package. VOSviewer was used to generate a visualization map of co-citation analysis and co-occurrence.

Results

A total of 2,285 articles related to chordoma were identified. The most influential and productive country/region was the United States, and Capital Medical University has published the most articles. Among all high-impact authors, Adrienne M. Flanagan had the highest average citation rate. Neurosurgery was the important periodical for chordoma research with the highest total/average citation rate. We focused on four hotspots in recent chordoma research. The research on surgical treatment and radiotherapy was relatively mature. The molecular signaling pathway, targeted therapy and immunotherapy for chordoma are not yet mature, which will be the future trends of chordoma research.

Conclusion

This study indicates that chordoma studies are increasing. Surgery and radiotherapy are well reported and always play fundamental roles in chordoma treatment. The molecular signaling pathway, targeted therapy, and immunotherapy of chordoma are the latest research hotspots.

Selinexor inhibits growth of patient derived chordomas in vivo as a single agent and in combination with abemaciclib through diverse mechanisms

Chordoma is a rare cancer that grows in the base of the skull and along the mobile spine from remnants of embryonic notochord tissue. The cornerstone of current treatments is surgical excision with adjuvant radiation therapy, although complete surgical removal is not always possible. Chordomas have high rates of metastasis and recurrence, with no approved targeted agents. Selinexor and eltanexor are selective inhibitors of nuclear export (SINE) that prevent the karyopherin protein exportin-1 (XPO1) from shuttling its cargo proteins through nuclear pore complexes out of the nucleus and into the cytoplasm. As cancer cells overexpress XPO1, and many of its cargos include tumor suppressor proteins and complexes bound to oncogene mRNAs, XPO1 inhibition can suppress oncogene translation and restore tumor suppressor protein activity in different cancer types. SINE compounds have exhibited anti-cancer activity in a wide range of hematological and solid tumor malignancies. Here we demonstrate the preclinical effectiveness of SINE compounds used as single agents or in combination with either the proteasome inhibitor, bortezomib, or the CDK4/6 inhibitor, abemaciclib, against various patient- derived xenograft (PDX) mouse models of chordoma, which included clival and sacral chordomas from adult or pediatric patients with either primary or metastatic disease, with either differentiated or poorly differentiated subtypes. SINE treatment significantly impaired tumor growth in all five tested chordoma models, with the selinexor and abemaciclib combination showing the strongest activity (tumor growth inhibition of 78-92%). Immunohistochemistry analysis of excised tumors revealed that selinexor treatment resulted in marked induction of apoptosis and reduced cell proliferation, as well as nuclear accumulation of SMAD4, and reduction of Brachyury and YAP1. RNA sequencing showed selinexor treatment resulted in differences in activated and repressed signaling pathways between the PDX models, including changes in WNT signaling, E2F pathways and glucocorticoid receptor signaling. This is consistent with SINE-compound mediated XPO1 inhibition exhibiting anti-cancer activity through a broad range of different mechanisms in different molecular chordoma subsets. Our findings validate the need for further investigation into selinexor as a targeted therapeutic for chordoma, especially in combination with abemaciclib.

[Chordoma-An update]

Chordomas are rare malignant tumors of the axial skeleton with notochordal differentiation. From a morphological point of view, chordomas display a broad spectrum ranging from the classical, conventional form not otherwise specified (NOS) to forms with hepatoid or renal carcinoma-like differentiation or even poorly or dedifferentiated variants. The detection of brachyury is highly characteristic, though not exclusive. The morphological differential diagnosis from a benign notochordal tumor (BNCT) requires integration of imaging since BNCT is limited to the vertebral bodies and is not osteolytic. Targeted therapy is a current research focus and cell lines as in vitro models are a precondition for the establishment and validation of this approach.

Optimization of the 4-anilinoquin(az)oline scaffold as epidermal growth factor receptor (EGFR) inhibitors for chordoma utilizing a toxicology profiling assay platform

The 4-anilinoquin(az)oline is a well-known kinase inhibitor scaffold incorporated in clinical inhibitors including gefitinib, erlotinib, afatinib, and lapatinib, all of which have previously demonstrated activity against chordoma cell lines in vitro. We screened a focused array of compounds based on the 4-anilinoquin(az)oline scaffold against both U-CH1 and the epidermal growth factor receptor (EGFR) inhibitor resistant U-CH2. To prioritize the hit compounds for further development, we screened the compound set in a multiparameter cell health toxicity assay. The de-risked compounds were then screened against a wider panel of patient derived cell lines and demonstrated low micromolar efficacy in cells. We also investigated the properties that gave rise to the toxophore markers, including the structural and electronic features, while optimizing for EGFR in-cell target engagement. These de-risked leads present a potential new therapeutic avenue for treatment of chordomas and new chemical tools and probe compound 45 (UNC-CA359) to interrogate EGFR mediated disease phenotypes.

Cervical Paraspinal Chordoma: A Literature Review with a Novel Case Report

Chordomas are rare malignant neoplasms, accounting for 1–4% of all primary bone tumors. Most spinal chordomas occur in the sacrococcygeal region and the base of the skull; however, 6% of chordomas are observed in the cervical spine. In these cases, the lesion is mainly located in the midline. These tumors slowly grow before becoming symptomatic and encase the surrounding vascular and nerve structures. Patients with advanced chordoma have a poor prognosis due to local recurrence with infiltration and destruction of adjacent bone and tissues. Systemic chemotherapy options have not been fully effective in these tumors, especially for recurrent chordomas. Thus, new combinations of currently available targeted molecular and biological therapies with radiotherapy have been proposed as potential treatment modalities. Here, the present paper describes the case of a 41-year-old male with a C2–C4 chordoma located paravertebrally, who underwent surgical resection with a debulking procedure for a cervical chordoma. Computed tomography angiography revealed a paraspinal mass with bone remodeling and the MRI showed a paravertebral mass penetrating to the spinal canal with a widening of the intervertebral C2–C3 foramen. Initially, the tumor was diagnosed as schwannoma based on its localization and imaging features; however, the histopathology specimen confirmed the diagnosis of chordoma. This case study highlights the effectivity of radical surgical resection as a mainstay treatment for chordomas, discusses neuroimaging, diagnosis, and the use of currently available targeted therapies and forthcoming treatment strategies, as alternative treatment options for chordoma.

Recurrent Metastatic Chordoma to the Liver: A Case Report and Review of the Literature

Chordoma is a rare malignant neoplasm derived from notochordal tissue that primarily affects the axial skeleton. Almost 40% of patients have non-cranial chordoma metastases. The most common metastatic sites are the lungs, bones, lymph nodes, and subcutaneous tissue. We present a 52-year female with a history of sacral chordoma presenting with abdominal fullness, early satiety, and a palpable abdominal mass. Abdominal magnetic resonance imaging (MRI) revealed an isolated, highly vascularized, and multilobed liver mass in the left lateral segment. The mass was surgically removed using a clean surgical margin. A histological examination and immunohistochemical staining were consistent with a metastatic chordoma. Two years later, follow-up imaging studies showed a 6.5 × 4.0 × 2.0 cm right liver lesion with multiple lungs, chest wall, pleural, and diaphragmatic lesions. Microscopic- and immunohistochemical staining revealed a recurrent metastatic chordoma. Herein, we present a unique case of metastatic recurrent chordoma in the liver with the involvement of other sites. To the best of our knowledge, no other case of recurrent liver metastasis has been reported.

Targeted delivery of cancer drug paclitaxel to chordomas tumor cells via an RNA nanoparticle harboring an EGFR aptamer

Paclitaxel has been extensively used in clinics for cancer treatment. However, its limited solubility in aqueous solution and high occurrence of side effects have also been widely reported. In this study, we constructed a biocompatible RNA nanoparticle delivery system (3WJ-EGFR_apt) that includes 3WJ (3-way junction) nanoparticle with a size of 4.85 ± 0.59 nm as a backbone and an EGFR (epidermal growth factor receptor) aptamer for specific targeting to chordomas cells, which owns the encapsulation ability of drug paclitaxel (PTX) for cancer therapy. Confocal microscopy and flow cytometry results confirmed 3WJ-EGFR_apt nanoparticle exhibited excellent specific targeting to chordomas cell U-CH2 which is an EGFR(+) cell line; while the 3WJ nanoparticle lose the targeted ability. Both of the two nanoparticles own no sensitivity to lung cancer cell H520 which is an EGFR(-) cell line. Moreover, the 3WJ-EGFR_apt nanoparticle encapsulated drug PTX could enhance the inhibition efficiency of chordomas tumor cells U-CH2 as compared to free PTX alone. This work demonstrates that RNA-3WJ constructed with a targeting aptamer provides a compromising targeted drug delivery ability on chordomas cells for therapeutics.

Advancement of PI3 Kinase Inhibitor Combination Therapies for PI3K-Aberrant Chordoma

Objectives  Targeted inhibitors of the PI3 kinase (PI3K) pathway have shown promising but incomplete antitumor activity in preclinical chordoma models. The aim of this study is to advance methodology for a high-throughput drug screen using chordoma models to identify new combination therapies for chordoma. Study Design  Present work is an in vitro study. Setting  The study conducted at an academic research laboratory. Materials and Methods  An in vitro study on automated high-throughput screening of chordoma cells was performed using a library of 1,406 drugs as both mono- and combination therapies with PI3K inhibitors. Combination indices were determined for dual therapies and synergistic outliers were identified as potential therapeutic agents. T (brachyury) siRNA knockdown in combination with PI3K pathway inhibition was also assessed. Results  Fifty-nine combination therapies were identified as having potential therapeutic efficacy. Effective combinations included PI3K inhibitors with GSK1838705A (ALK/IGF-1R inhibitor), LY2874455 (VEGFR/FGFR inhibitor), El1 (selective Ezh2 inhibitor), and (-)-p-bromotetramisole oxalate (alkaline phosphatase inhibitor). The top ranking targets identified included ALK, PDGFR, VEGFR, aurora kinase, and BCL-2. T (brachyury) inhibition produced significant reduction in cell viability and growth; however PI3K inhibition in combination with T (brachyury) knockdown did not result in further reduction in growth and viability in vitro. Conclusion  High throughput with in vitro combination screening is feasible with chordoma cells and allows for rapid identification of synergistic dual-therapies. Potential combination therapies and targetable pathways were identified. T (brachyury) knockdown produced significant reduction in cell viability, but did not show additional benefit with PI3K pathway inhibition in this model. Further in vitro and in vivo validation of these therapeutic combinations is warranted.

Weekly cisplatin with or without imatinib in advanced chordoma: A retrospective case-series analysis from the Italian Rare Cancers Network

BACKGROUND

To report on a retrospective case-series analysis of weekly cisplatin (wCDDP) as a single agent or combined with imatinib (wCDDP/I) in patients with advanced chordoma treated within the Italian Rare Cancer Network.

METHODS

Adult patients with a diagnosis of advanced, brachyury-positive chordoma, treated from April 2007 to October 2020 with wCDDP or wCDDP/I were retrospectively identified. Imatinib was withheld at the same time as wCDDP. Response according to Response Evaluation Criteria in Solid Tumors, overall survival (OS), and progression-free survival (PFS) were analyzed.

RESULTS

Thirty-three consecutive patients were identified (wCDDP as front-line n = 8 [24.2%]; wCDDP as a further line n = 25 [75.8%]; prior imatinib n = 25 [75.8%]; evidence of progression before starting wCDDP n = 33). Of 32 patients evaluable for response (wCDDP, n = 22 [68.8%]; wCDDP/I, n = 10 [31.3%]), best response was stable disease (SD) in 27 patients (84.3%) and progression in 5 patients (15.6%). At a median follow-up of 54 months, the median OS (m-OS) was 30.3 months (interquartile range [IQR], 18.1-56.6), the m-PFS was 8.0 months (IQR, 5.1-17.0), the 6-month PFS rate was 65.2%, and the 12-month PFS rate was 30.3%. Of 22 patients who received wCDDP, the best response was SD in 18 patients (81.8%) and progression in 4 patients (18.2%), and the m-PFS was 8.0 months (IQR, 5.1-17.0 months). Of 10 patients who received treatment with wCDDP/I, the best response was SD in 9 patients (90%) and progression in 1 patient (10%), and the m-PFS was 9.3 months (IQR, 4.9-26.5 months).

CONCLUSIONS

This series suggests that wCDDP, both as a single agent and combined with imatinib, has antitumor activity in chordoma. Although no dimensional responses were observed, 65% and 30% of previously progressive patients were progression-free at 6 and 12 months, respectively. A prospective study is warranted.

Role of T-box genes in cancer, epithelial-mesenchymal transition, and cancer stem cells

Sharing a common DNA binding motif called T-box, transcription factor T-box gene family controls embryonic development and is also involved in cancer progression and metastasis. Cancer metastasis shows therapy resistance and involves complex processes. Among them, epithelial-mesenchymal transition (EMT) triggers cancer cell invasiveness and the acquisition of stemness of cancer cells, called cancer stem cells (CSCs). CSCs are a small fraction of tumor bulk and are capable of self-renewal and tumorsphere formation. Recent progress has highlighted the critical roles of T-box genes in cancer progression, EMT, and CSC function, and such regulatory functions of T-box genes have emerged as potential therapeutic candidates for cancer. Herein we summarize the current understanding of the regulatory mechanisms of T-box genes in cancer, EMT, and CSCs, and discuss the implications of targeting T-box genes as anticancer therapeutics.

B7-H3 as a Target for CAR-T Cell Therapy in Skull Base Chordoma

Objective

chordomas are rare bone tumors with few therapeutic options. Skull base and sacrum are the two most common origin sites. Immunotherapies are emerging as the most promising approaches to fight various cancers. This study tends to identify new cell surface targets for immunotherapeutic options of skull base chordomas.

Methods

we profiled 45 skull base chordoma clinical samples by immunohistochemistry for the expression of six CAR-Targets (PD-L1, B7-H3, B7-H4, VISTA, HER2 and HER3). In addition, we generated B7-H3 targeted CAR-T-cells and evaluated their antitumor activities in vitro.

Results

We found that B7-H3 was positively stained in 7 out of 45 (16%) chordoma samples and established an expression hierarchy for these antigens (B7-H3 > HER3 > PD-L1 > HER2 = VISTA = B7-H4). We then generated a B7-H3 targeted CAR vector and demonstrated that B7-H3-CAR-T-cells recognized antigen positive cells and exhibited significant antitumor effects, including suppression of tumor spheroid formation, CAR-T-cell activation and cytokine secretion.

Conclusions

Our results support B7-H3 might serve as a promising target for CAR-T-cell therapies against chordomas.

Association between TBXT rs2305089 polymorphism and chordoma in Iranian patients identified by a developed T-ARMS-PCR assay

Background

Chordoma is a locally aggressive bone tumor with a high capability of recurrence. Because chordoma often occurs at critical locations next to neurovascular structures, there is an urgent need to introduce validated biomarkers. T‐box transcription factor T (TBXT; OMIM: 601397) plays an important role in the pathogenesis and survival of chordoma cells.

Methods

Herein, we aimed to show whether rs2305089 polymorphism is correlated with chordoma in the Iranian population. In order to detect rs2305089, tetra‐primer amplification refractory mutation system‐polymerase chain reaction (T‐ARMS‐PCR) was used. In total, 19 chordoma patients and 108 normal healthy individuals were recruited and screened using T‐ARMS‐PCR. The results were subsequently validated by Sanger sequencing.

Results

The genotype distributions and allele frequencies were significantly different among the patient and healthy groups (p‐value <0.05). The A allele of rs2305089 showed a significant positive association with chordoma risk (p‐value <0.05). DNA sequencing verified the T‐ARMS‐PCR results as well. This study demonstrated the association between TBXT rs2305089 and chordoma in an Iranian population using a simple, accurate, and cost‐effective T‐ARMS‐PCR assay.

Conclusions

Our results were in line with those of previous studies showing that TBXT rs2305089 is associated with chordoma development. We also developed an efficient T‐ARMS‐PCR assay to determine the genotype of rs2305089.

CMTM3 suppresses chordoma progress through EGFR/STAT3 regulated EMT and TP53 signaling pathway

BACKGROUND

Chordomas are rare, slow-growing and locally aggressive bone sarcomas. At present, chordomas are difficult to manage due to their high recurrence rate, metastasis tendency and poor prognosis. The underlying mechanisms of chordoma tumorigenesis and progression urgently need to be explored to find the effective therapeutic targets. Our previous data demonstrates that EGFR plays important roles in chordoma development and CKLF-like MARVEL transmembrane domain containing (CMTM)3 suppresses gastric cancer metastasis by inhibiting the EGFR/STAT3/EMT signaling pathway. However, the roles and mechanism of CMTM3 in chordomas remain unknown.

METHODS

Primary chordoma tissues and the paired adjacent non-tumor tissues were collected to examine the expression of CMTM3 by western blot. The expression of CMTM3 in chordoma cell lines was tested by Real-time PCR and western blot. CCK-8 and colony forming unit assay were performed to delineate the roles of CMTM3 in cell proliferation. Wound healing and Transwell assays were performed to assess cell migration and invasion abilities. A xenograft model in NSG mice was used to elucidate the function of CMTM3 in vivo. Signaling pathways were analyzed by western blot and IHC. RNA-seq was performed to further explore the mechanism regulated by CMTM3 in chordoma cells.

RESULTS

CMTM3 expression was downregulated in chordoma tissues compared with paired normal tissues. CMTM3 suppressed proliferation, migration and invasion of chordoma cells in vitro and inhibited tumor growth in vivo. CMTM3 accelerated EGFR degradation, suppressed EGFR/STAT3/EMT signaling pathway, upregulated TP53 expression and enriched the TP53 signaling pathway in chordoma cells.

CONCLUSIONS

CMTM3 inhibited tumorigenesis and development of chordomas through activating the TP53 signaling pathway and suppressing the EGFR/STAT3 signaling pathway, which suppressed EMT progression. CMTM3 might be a potential therapeutic target for chordomas.

Drug combination screening as a translational approach toward an improved drug therapy for chordoma

Purpose

Drug screening programmes have revealed epidermal growth factor receptor inhibitors (EGFR_is) as promising therapeutics for chordoma, an orphan malignant bone tumour, in the absence of a known genetic driver. Concurrently, the irreversible EGFR_i afatinib (Giotrif®) is being evaluated in a multicentric Phase II trial. As tyrosine kinase inhibitor (TKI) monotherapies are invariably followed by resistance, we aimed to evaluate potential therapeutic combinations with EGFR_is.

Methods

We screened 133 clinically approved anticancer drugs as single agents and in combination with two EGFR_is (afatinib and erlotinib) in the clival chordoma cell line UM-Chor1. Synergistic combinations were analysed in a 7 × 7 matrix format. The most promising combination was further explored in clival (UM-Chor1, MUG-CC1) and sacral (MUG-Chor1, U-CH1) chordoma cell lines. Secretomes were analysed for receptor tyrosine kinase ligands (EGF, TGF-α, FGF-2 and VEGF-A) upon drug treatment.

Results

Drugs that were active as single agents (n = 45) included TKIs, HDAC and proteasome inhibitors, and cytostatic drugs. Six combinations were analysed in a matrix format: n = 4 resulted in a significantly increased cell killing (crizotinib, dabrafenib, panobinostat and doxorubicin), and n = 2 exhibited no or negligible effects (regorafenib, venetoclax). Clival chordoma cell lines were more responsive to combined EGFR-MET inhibition. EGFR-MET cross-talk (e.g. via TGF-α secretion) likely accounts for the synergistic effects of EGFR-MET inhibition.

Conclusion

Our screen revealed promising combinations with EGFR_is, such as the ALK/MET-inhibitor crizotinib, the HDAC-inhibitor panobinostat or the topoisomerase-II-inhibitor doxorubicin, which are part of standard chemotherapy regimens for various bone and soft-tissue sarcomas.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13402-021-00632-x.

Multiple malignant tumors in a patient with familial chordoma, a case report

Background

Chordoma is a rare bone tumor that is typically resistant to chemotherapy and is associated with genetic abnormalities of the T-box transcription factor T (TBXT) gene, which encodes the transcription factor brachyury. Brachyury is felt to be a major contributor to the development of chordomas.

Case presentation

We describe a 67-year-old woman who developed an undifferentiated pleomorphic sarcoma in her thigh. Despite treatment with standard chemotherapy regimens, she had a rapidly progressive course of disease with pulmonary metastases and passed away 8 months from diagnosis with pulmonary complications. Her medical history was remarkable in that she had a spheno-occipital chordoma at age 39 and later developed multiple other tumors throughout her life including Hodgkin lymphoma and squamous cell carcinoma and basal cell carcinoma of the skin. She had a family history of chordoma and her family underwent extensive genetic study in the past and were found to have a duplication of the TBXT gene.

Conclusions

Brachyury has been found to associate with tumor progression, treatment resistance, and metastasis in various epithelial cancers, and it might play roles in tumorigenesis and aggressiveness in this patient with multiple rare tumors and germ line duplication of the TBXT gene. Targeting this molecule may be useful for some malignancies.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-021-01064-0.

Chordoma: A Review and Differential Diagnosis

CONTEXT.—

Chordomas are uncommon malignant neoplasms with notochordal differentiation encountered by neuropathologists, bone/soft tissue pathologists, and general surgical pathologists. These lesions most commonly arise in the axial skeleton. Optimal therapy typically involves complete surgical resection, which is often technically difficult owing to the anatomic location, leading to a high rate of recurrence. Lesions have been generally resistant to radiation and chemotherapy; however, experimental studies involving targeted therapy and immunotherapy are currently underway.

OBJECTIVE.—

To summarize the clinical and pathologic findings of the various types of chordoma (conventional chordoma, dedifferentiated chordoma, and poorly differentiated chordoma), the differential diagnosis, and recent advances in molecular pathogenesis and therapeutic modalities that are reliant on accurate diagnosis.

DATA SOURCES.—

Literature review based on PubMed searches containing the term "chordoma" that address novel targeted and immunomodulatory therapeutic modalities; ongoing clinical trials involved in treating chordoma with novel therapeutic modalities identified through the Chordoma Foundation and ClinicalTrials.gov; and the authors' practice experience combined with various authoritative texts concerning the subject.

CONCLUSIONS.—

Chordoma is a clinically and histologically unique malignant neoplasm, and numerous diagnostic considerations must be excluded to establish the correct diagnosis. Treatment options have largely been centered on surgical excision with marginal results; however, novel therapeutic options including targeted therapy and immunotherapy are promising means to improve prognosis.

AZD8055 enhances in vivo efficacy of afatinib in chordomas

Chordomas are primary bone tumors that arise in the cranial base, mobile spine, and sacrococcygeal region, affecting patients of all ages. Currently, there are no approved agents for chordoma patients. Here, we evaluated the anti-tumor efficacy of small molecule inhibitors that target oncogenic pathways in chordoma, as single agents and in combination, to identify novel therapeutic approaches with the greatest translational potential. A panel of small molecule compounds was screened in vivo against patient-derived xenograft (PDX) models of chordoma, and potentially synergistic combinations were further evaluated using chordoma cell lines and xenograft models. Among the tested agents, inhibitors of EGFR (BIBX 1382, erlotinib, and afatinib), c-MET (crizotinib), and mTOR (AZD8055) significantly inhibited tumor growth in vivo but did not induce tumor regression. Co-inhibition of EGFR and c-MET using erlotinib and crizotinib synergistically reduced cell viability in chordoma cell lines but did not result in enhanced in vivo activity. Co-inhibition of EGFR and mTOR pathways using afatinib and AZD8055 synergistically reduced cell viability in chordoma cell lines. Importantly, this dual inhibition completely suppressed tumor growth in vivo, showing improved tumor control. Together, these data demonstrate that individual inhibitors of EGFR, c-MET, and mTOR pathways suppress chordoma growth both in vitro and in vivo. mTOR inhibition increased the efficacy of EGFR inhibition on chordoma growth in several preclinical models. The insights gained from our study potentially provide a novel combination therapeutic strategy for patients with chordoma. © 2021 The Authors. The Journal of Pathology published by John Wiley & Sons, Ltd. on behalf of The Pathological Society of Great Britain and Ireland.

Chordoma: Current status, problems, and future directions

Chordoma is a rare tumor that occurs along the axial spine in pediatrics and adults, with an incidence of approximately 350 cases per year in the United States. While typically described as slow-growing, many patients will eventually develop loco-regional relapse or metastatic disease with few treatment options. Despite numerous efforts over the last 10+ years, effective treatments for patients are lacking. As subtypes of chordoma are identified and described in more detail, further knowledge regarding the natural history of each type, tumor location, age differences, genomic variability, and an overall better understanding of chordoma may be the key to developing meaningful clinical trials and effective therapies for patients with chordoma.

Immunotherapy for Chordoma and Chondrosarcoma: Current Evidence

Chordomas and chondrosarcomas are rare but devastating neoplasms that are characterized by chemoradiation resistance. For both tumors, surgical resection is the cornerstone of management. Immunotherapy agents are increasingly improving outcomes in multiple cancer subtypes and are being explored in chordoma and chondrosarcoma alike. In chordoma, brachyury has been identified as a prominent biomarker and potential molecular immunotherapy target as well as PD-1 inhibition. While studies on immunotherapy in chondrosarcoma are sparse, there is emerging evidence and ongoing clinical trials for PD-1 as well as IDH inhibitors. This review highlights potential biomarkers and targets for immunotherapy in chordoma and chondrosarcoma, as well as current clinical evidence and ongoing trials.

Targeted Therapy for Chordoma: Key Molecular Signaling Pathways and the Role of Multimodal Therapy

BACKGROUND

Chordoma is a rare but devastating tumor that arises in the cranial skull base or spine. There are currently no US Food and Drug Administration-approved targeted therapies for chordoma, and little understanding of whether using more than one therapy has benefit over monotherapy.

OBJECTIVE

The objective of this study was to systematically review the current status of clinical trials completed for patients with chordoma to determine if multimodal therapy offers a benefit in progression-free survival over monomodal therapy.

METHODS

We performed a systematic review of the literature according to Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA) guidelines to review the available clinical trials of targeted therapy for chordoma. We compiled the clinical data to determine if there is a benefit of multimodal therapy over monotherapy.

RESULTS

Our search resulted in 11 clinical trials including 270 patients with advanced chordoma who were treated with targeted therapies. The most commonly employed targeted therapies acted within the following pathways: platelet-derived growth factor receptor (187 patients), vascular endothelial growth factor (66 patients), and mammalian target of rapamycin (43 patients). Reported progression-free survival for included studies ranged from 2.5 to 58 months, with the longest progression-free survival in a trial that included a platelet-derived growth factor receptor inhibitor, nilotinib, and concurrent radiotherapy (58.2 months). There was a higher range of progression-free survival for trials treating patients with multimodal therapy (10.2-14 months vs 2.5-9.2 months, except for a monotherapy trial published in 2020 with a progression-free survival of 18 months), and those published in 2018 or later (14-58.2 months vs 2.5-10.2 months). Only 23% of patients with chordoma in published clinical trials have been treated with multimodal therapy.

CONCLUSIONS

Progression-free survival may be enhanced by the use of targeted therapy with concurrent radiotherapy, use of multimodal therapy, and use of newer targeted therapy. Future clinical trials should consider use of concurrent radiotherapy and multimodal therapy for patients with advanced chordoma.

Knockdown of TMED3 inhibits cell viability and migration and increases apoptosis in human chordoma cells

Chordoma is a rare low‑grade tumor of the axial skeleton. Over previous decades, a range of targeted drugs have been used for treating chordoma, with more specific and effective therapies under investigation. Transmembrane Emp24 protein transport domain containing 3 (TMED3) is a novel gene reported to be a regulator of oncogenesis, cancer development and metastasis; however, its role in chordoma remains unclear. In the present study, the expression of TMED3 was investigated in chordoma cells, and the effect of TMED3 knockdown on chordoma development was examined in vitro and in vivo, followed by exploration of differentially expressed proteins in TMED3‑silenced chordoma cells via an apoptosis antibody array. Reverse transcription‑quantitative PCR and western blot assays were performed to determine the expression levels. It was revealed that TMED3 was highly expressed in chordoma, and that knockdown of TMED3 inhibited cell viability and migration, and enhanced the apoptosis of chordoma cells. Additionally, knockdown of TMED3 inhibited the expression of Bcl‑2, heat shock protein 27, insulin‑like growth factor (IGF)‑I, IGF‑II, IGF binding protein‑2, Livin, Akt, CDK6 and cyclin D1 proteins, whereas MAPK9 was upregulated. Furthermore, a xenograft nude mice model demonstrated that TMED3 expression promoted tumor growth. Collectively, the present findings suggested that knockdown of TMED3 inhibited cell viability and migration, and enhanced apoptosis in chordoma cells, and that TMED3 may be a novel target for chordoma therapy.

Chordoma-Current Understanding and Modern Treatment Paradigms

Chordoma is a low-grade notochordal tumor of the skull base, mobile spine and sacrum which behaves malignantly and confers a poor prognosis despite indolent growth patterns. These tumors often present late in the disease course, tend to encapsulate adjacent neurovascular anatomy, seed resection cavities, recur locally and respond poorly to radiotherapy and conventional chemotherapy, all of which make chordomas challenging to treat. Extent of surgical resection and adequacy of surgical margins are the most important prognostic factors and thus patients with chordoma should be cared for by a highly experienced, multi-disciplinary surgical team in a quaternary center. Ongoing research into the molecular pathophysiology of chordoma has led to the discovery of several pathways that may serve as potential targets for molecular therapy, including a multitude of receptor tyrosine kinases (e.g., platelet-derived growth factor receptor [PDGFR], epidermal growth factor receptor [EGFR]), downstream cascades (e.g., phosphoinositide 3-kinase [PI3K]/protein kinase B [Akt]/mechanistic target of rapamycin [mTOR]), brachyury—a transcription factor expressed ubiquitously in chordoma but not in other tissues—and the fibroblast growth factor [FGF]/mitogen-activated protein kinase kinase [MEK]/extracellular signal-regulated kinase [ERK] pathway. In this review article, the pathophysiology, diagnosis and modern treatment paradigms of chordoma will be discussed with an emphasis on the ongoing research and advances in the field that may lead to improved outcomes for patients with this challenging disease.

Clinical Implication of Systemic Immune-Inflammation Index and Prognostic Nutritional Index in Skull Base Chordoma Patients

Inflammation associated markers and nutritional indexes are associated with survival, and act as novel prognostic grading systems in patients with cancer, though the role of these markers in chordoma remains unclear. The current study aimed to characterize systemic immune-inflammation index (SII) and prognostic nutritional index (PNI), and their relationship with clinicopathological data and survival in skull base chordoma. Our retrospective study enrolled 183 patients with primary skull base chordoma who received surgical treatment. Clinicopathological data and preoperative blood tests including neutrophil, lymphocyte, platelet counts and albumin level were collected from medical records. Neutrophil lymphocyte ratio (NLR), platelet lymphocyte ratio (PLR), SII, PNI were calculated and the optimal cut-off values of these markers were used for further survival analysis via Kaplan–Meier survival analysis and Cox proportional hazards regression analysis. The value of NLR, PLR, SII, and PNI in skull base chordoma ranged from 0.44–6.48, 45.36–273.94, 113.37–1761.45, and 43.40–70.65, respectively. PNI was significantly correlated with patients' sex (p = 0.005) and age (p = 0.037). SII was positively correlated with NLR and PLR, but negatively correlated with PNI. The median overall survival (OS) time was 74.0 months and Kaplan–Meier survival analysis indicated that all four indexes were associated with OS. Multivariable Cox proportional hazards regression analysis identified that high SII was an independent prognostic factor for poor OS. More importantly, patients with high SII and PNI had the worst outcomes and combined use of SII and PNI increased the predictive ability for patients' survival in skull base chordoma. Our results suggest SII and PNI may be effective prognostic indicators of OS for patients with primary skull base chordoma after surgical resection.

Dual roles of ATP-binding site in protein kinases: Orthosteric inhibition and allosteric regulation

Protein kinases use ATP to phosphorylate other proteins. Phosphorylation (p) universally orchestrates a fine-tuned network modulating a multitude of biological processes. Moreover, the start of networks, ATP-binding site, has been recognized dual roles to impact protein kinases function: (i) orthosteric inhibition, via being blocked to interference ATP occupying and (ii) allosteric regulation, via being altered first to induce further conformational changes. The above two terminologies are widely used in drug design, which has acquired quite a significant progress in the protein kinases field over the past 2 decades. Most small molecular inhibitors directly compete with ATP to implement orthosteric inhibition, still exhibiting irreplaceable and promising therapeutic effects. Additionally, numerous inhibitors can paradoxically lead protein kinases to hyperphosphorylation, even activation, indicative of the allosteric regulation role of the ATP-binding site. Here, we review the quintessential examples that apply for the dual roles in diverse ways. Our work provides an insight into the molecular mechanisms under the dual roles and will be promisingly instructive for future drug development.

Genetic Testing Distinguishes Multiple Chondroid Chordomas with Neuraxial Bone Metastases from Multicentric Tumors

Background

Chordomas are rare malignant bone tumors preferentially forming in neuraxial bones. Chondroid chordoma is a subtype of chordoma. Chordomas reportedly present as synchronous multiple lesions upon initial diagnosis. However, it remains unknown whether these lesions are multicentric or metastatic multiple chordoma tumors. Case Presentation. Here, we present the case of a 57-year-old woman with multiple chordomas at the clivus, C6, and T12 upon initial presentation. Sequential surgeries and radiotherapy were performed for these lesions, and postoperative histological diagnosis revealed that all lesions were chondroid chordomas. Next-generation sequencing revealed that these lesions harbored a common somatic mutation in epidermal growth factor receptor (EGFR), c.3617A>C, which is not considered a pathogenic chordoma mutation, thus indicating that these lesions were not multicentric but rather multiple metastatic tumors. Subsequent multiple metastases to the lung and appendicular and axial bones were detected 15 months after the initial surgery. Recurrent lesions at the clivus progressed despite EGFR-targeted therapy, surgery, and radiotherapy.

Conclusion

The present evidence indicates that multiple chordomas in this case were caused by multiple metastases rather than multicentric lesions. Multiple presentations of chordoma imply systemic dissemination of tumor cells, and novel efficient systemic therapy is required to treat this disease.

[Primary extra-axial chondroid chordoma of the anterior nasal septum: case report of a rare chordoma with literature review]

An 87-year-old patient reported a nodular, progressively enlarging mass of the anterior nasal septum leading to partial obstruction of the nostrils. The tumor showed no infiltration of the subcutis, bone, or paranasal sinuses in imaging or intraoperatively. Histological examination revealed a chondroid tumor with lobular growth and physaliferous cell morphology. Immunohistochemistry revealed a brachyury-positive tumor without EWSR1 rearrangement, leading to the diagnosis of a chondroid chordoma. The reported case demonstrates the differential diagnostic considerations pertaining to this rare tumor, which can also have an untypical and very rare extra-axial location. Review of the literature identified 34 primary extraosseous chordomas of the nose, nasopharynx, and paranasal sinuses, and allowed the nasal chordoma presented herein to be included in this group of extra-axial chordomas.

Inhibition of Histone H3K27 Demethylases Inactivates Brachyury (TBXT) and Promotes Chordoma Cell Death

Expression of the transcription factor brachyury (TBXT) is normally restricted to the embryo, and its silencing is epigenetically regulated. TBXT promotes mesenchymal transition in a subset of common carcinomas, and in chordoma, a rare cancer showing notochordal differentiation, TBXT acts as a putative oncogene. We hypothesized that TBXT expression is controlled through epigenetic inhibition to promote chordoma cell death. Screening of five human chordoma cell lines revealed that pharmacologic inhibition of the histone 3 lysine 27 demethylases KDM6A (UTX) and KDM6B (JMJD3) leads to cell death. This effect was phenocopied by dual genetic inactivation of KDM6A/B using CRISPR/Cas9. Inhibition of KDM6A/B with a novel compound KDOBA67 led to a genome-wide increase in repressive H3K27me3 marks with concomitant reduction in active H3K27ac, H3K9ac, and H3K4me3 marks. TBXT was a KDM6A/B target gene, and chromatin changes at TBXT following KDOBA67 treatment were associated with a reduction in TBXT protein levels in all models tested, including primary patient-derived cultures. In all models tested, KDOBA67 treatment downregulated expression of a network of transcription factors critical for chordoma survival and upregulated pathways dominated by ATF4-driven stress and proapoptotic responses. Blocking the AFT4 stress response did not prevent suppression of TBXT and induction of cell death, but ectopic overexpression of TBXT increased viability, therefore implicating TBXT as a potential therapeutic target of H3K27 demethylase inhibitors in chordoma. Our work highlights how knowledge of normal processes in fetal development can provide insight into tumorigenesis and identify novel therapeutic approaches. SIGNIFICANCE: Pharmacologic inhibition of H3K27-demethylases in human chordoma cells promotes epigenetic silencing of oncogenic TBXT, alters gene networks critical to survival, and represents a potential novel therapy.

Isolated cervical extraosseous intradural chordoma attached to the C5 nerve root: a case report

Background

As chordomas are slow growing and locally invasive with high recurrence rates, initial recommendations include complete surgical resection with or without radiation therapy. A large proportion of recurrences occur years after initial resection necessitating lengthy follow-up. The novel biomarker brachyury and the repurposing of pharmaceutical products have the potential to substantially impact long-term recurrence rates.

Case presentation

A 43-year-old woman presented with an isolated, cervical extraosseous intradural extramedullary chordoma attached to a nerve root underwent a C3-5 laminectomy, C3-5 lateral mass screw instrumentation, and mass resection. All symptoms resolved by the 12-month postoperative follow-up visit.

Conclusions

This is the first report of an isolated, cervical extraosseous intradural extramedullary chordoma attached to a nerve root, and this case adds to the previous six Type IV chordomas in the literature. Unfortunately, the very rare form of extraosseous intradural chordoma is poorly understood: the lack of detailed knowledge in how they are differentiated from other forms of chordoma confounds the development of optimal treatment strategies and follow-up guidelines.

Synergistic drug combinations and machine learning for drug repurposing in chordoma

Chordoma is a devastating rare cancer that affects one in a million people. With a mean-survival of just 6 years and no approved medicines, the primary treatments are surgery and radiation. In order to speed new medicines to chordoma patients, a drug repurposing strategy represents an attractive approach. Drugs that have already advanced through human clinical safety trials have the potential to be approved more quickly than de novo discovered medicines on new targets. We have taken two strategies to enable this: (1) generated and validated machine learning models of chordoma inhibition and screened compounds of interest in vitro. (2) Tested combinations of approved kinase inhibitors already being individually evaluated for chordoma. Several published studies of compounds screened against chordoma cell lines were used to generate Bayesian Machine learning models which were then used to score compounds selected from the NIH NCATS industry-provided assets. Out of these compounds, the mTOR inhibitor AZD2014, was the most potent against chordoma cell lines (IC50 0.35 µM U-CH1 and 0.61 µM U-CH2). Several studies have shown the importance of the mTOR signaling pathway in chordoma and suggest it as a promising avenue for targeted therapy. Additionally, two currently FDA approved drugs, afatinib and palbociclib (EGFR and CDK4/6 inhibitors, respectively) demonstrated synergy in vitro (CI50 = 0.43) while AZD2014 and afatanib also showed synergy (CI50 = 0.41) against a chordoma cell in vitro. These findings may be of interest clinically, and this in vitro- and in silico approach could also be applied to other rare cancers.

Prognostic impact of the "Sekhar grading system for cranial Chordomas" in patients treated with pencil beam scanning proton therapy: an institutional analysis

BACKGROUND

Skull base chordomas are rare and heterogeneously behaving tumors. Though still classified as benign they can grow rapidly, are locally aggressive, and have the potential to metastasize. To adapt the treatment to the specific needs of patients at higher risk of recurrence, a pre-proton therapy prognostic grading system would be useful. The aim of this retrospective analysis is to assess prognostic factors and the "Sekhar Grading System for Cranial Chordomas" (SGSCC) by evaluating the larger cohort of patients treated at our institution as to determine its reproducibility and ultimately to ensure more risk adapted local treatments for these challenging tumors.

METHODS

We analyzed 142 patients treated for skull base chordomas between 2004 and 2016. We focused the analysis on the 5 criteria proposed for the SGSCC (tumor size, number of anatomic regions and vessels involved, intradural invasion, as well as recurrence after prior treatment) and classified our patients according to their score (based on the above mentioned criteria) into three prognostic groups, low-risk, intermediate-risk and high-risk. The three groups were then analyzed in regards of local control, local recurrence-free survival and overall survival.

RESULTS

The median follow up was 52 months (range, 3-152). We observed 34 (24%) patients with a local recurrence, resulting in a local control of 75% at 5 years. Overall survival was 83% at 5 years, 12 (9%) patients had died due to local progression. When split into the three prognostic groups according to the SGSCC the observed local control was 90, 72 and 64% (p = 0.07) in the low-, intermediate- and high-risk group, respectively. A similar correlation was observed for local recurrence-free survival with 93, 89 and 66% (p = 0.05) and for overall survival with 89, 83 and 76% (p = 0.65) for the same prognostic groups.

CONCLUSIONS

After splitting our patient cohort into the three SGSCC risk groups, we found a trend towards better outcome for those patients with lower as opposed to higher scores. These results suggest that this prognostic grading system published by Sekhar et al. could be integrated in the management decision-tree for patients with skull base chordoma.

Skull base chordomas review of current treatment paradigms

Background

Chordomas are locally invasive neoplasms, arising from notochordal remnants and can appear anywhere along the axial skeleton. Local recurrences are common, and distant metastases may occur years after the initial presentation.

Methods

Literature review of current treatment strategies for chordomas of the skull base.

Results

Surgery is the mainstay of treatment and complete resection has paramount importance for prognosis.

When complete resection is not achieved recurrent disease is common. The anatomical complexity of the skull base makes resection complex. Endonasal endoscopic approaches to the clivus has become increasingly favored in recent years although addressing reconstruction of the skull base to prevent CSF leak may be challenging.

Evidence suggests that radiotherapy should not be considered as a primary single modality when trying to achieve cure of the disease. Nonetheless, immediate post-operative radiotherapy improves survival. Many strategies have been suggested to preserve sensitive vital structures in the skull base during treatment but as for survival there is no evidence of advantage when comparing adjuvant therapy with photon radiotherapy, gamma knife surgery, proton beam therapy, and carbon ion radiation therapy.

There is no evidence to support cytotoxic chemotherapy in the treatment of chordomas but targeted therapies have started to show promise. Several optional molecular targets exist. Brachyury is overexpressed in 95% of chordomas but not in other mesenchymal neoplasms. However, its precise role in chordoma pathogenesis is currently unclear, and its cellular location in the nucleus makes it difficult to target. The inhibition of brachyury in chordoma cell lines induces growth arrest and apoptosis. This does not have clinical application to date. There are retrospective results with different molecular targeted therapies for advanced chordomas with some effectiveness.

Conclusion

Despite improvements made in the past 10 years in our knowledge of chordoma biology, available therapies still offer a limited benefit. There is an unmet need for new therapeutic options for patients with advanced disease. Therefore, patients with advanced disease should be encouraged to participate in clinical trials when and where available.

[Chordoma: is there a molecular basis for diagnosis and treatment?]

Chordomas are malignant bone tumours with a reported annual incidence of 0.08 per 100,000 cases. They show a notochordal differentiation and are characterised by their nuclear expression of brachyury (TBXT). Chordomas are localised in the axial skeleton, where they occur from the clivus to the sacrococcygeal region. They are slow growing, locally destructive tumours, and are often not diagnosed until they have reached an advanced stage. Putative precursor-lesions are benign notochordal cell lesions, which are microscopically small and intraosseous. Different histological chordoma subtypes exist, which differ in their prognosis. To date, there are no known recurrent genetic drivers for this disease. Brachyury seems to play a key role in the pathogenesis of chordoma, though the detailed mechanism still needs to be elucidated. Surgical en bloc resection with negative margins is the only curative treatment for this disease. High-dose irradiation, particularly with protons and carbon ions, is a therapeutic alternative in cases of inoperable tumours. Currently, there is no approved medical treatment for chordoma. Clinical trials exploring additional therapeutic modalities are ongoing.

Brachyury: Strategies for Drugging an Intractable Cancer Therapeutic Target

New approaches to drug discovery are unlocking enormous therapeutic potential residing in cancer-specific molecules. Brachyury is emerging as an exciting new drug target for the rare bone cancer chordoma. Here, recent advances targeting Brachyury in chordoma are discussed and how these might open doors to the targeting of other, more common cancer types.

Chordoma: update on disease, epidemiology, biology and medical therapies

PURPOSE OF REVIEW

Chordoma is an exceedingly rare subtype of bone sarcoma. This review aims to provide a comprehensive insight into chordoma epidemiology, and an update on the recent advances in disease, biology and medical therapies.

RECENT FINDINGS

The incidence of chordoma is approximately 0.08/100 000 and the 5-year overall age-adjusted relative survival is 72% in the United States and 61% in Europe. Over the last years, significant steps forwards have been done in the comprehension of chordoma complexity, with insights gained into the biology and morphology of this disease. New entities have been described and potentially druggable molecular targets identified. This is becoming all the more relevant today, as new potentially active agents are under development.

SUMMARY

Chordoma is a complex disease because of its rarity, biological heterogeneity and peculiar clinical behaviour. Despite the progress done, the outcome in this disease remains unsatisfactory and the identification of active systemic treatments remains an urgent, unmet medical need.

Rationale for the advancement of PI3K pathway inhibitors for personalized chordoma therapy

PURPOSE

Chordomas are rare and serious tumors with few effective treatments outside of aggressive surgery and radiation. Targeted therapies may present a more effective option for a subset of patients with lesions possessing certain genetic biomarkers.

METHODS

A small molecule inhibitor library was tested in patient-derived UM-Chor1 cells to identify targeted therapies with potential efficacy. Targeted exome sequencing of UM-Chor1 and UM-Chor2 cells was performed to investigate genetic aberrations in relevant pathways. Chordoma cell lines were treated with inhibitors of the phosphotidylinositol 3-kinase (PI3K), epidermal growth factor receptor (EGFR), and cyclin dependent kinase (CDK) pathways, and responses were determined using resazurin cell viability assays, Annexin V apoptosis assays, and western blotting. Pan-PI3K inhibitor BKM120 was also tested in five chordoma xenograft models.

RESULTS

Unbiased small molecule profiling nominated PI3K-AKT-mTOR pathway inhibitors as a promising therapy in chordoma, and genetic analyses of UM-Chor1 and UM-Chor2 cell lines revealed aberrations in PTEN, EGFR, and CDKN2A. Treatment of UM-Chor1 and UM-Chor2 with targeted PI3K, EGFR, and CDK inhibitors inhibited growth and proliferation and induced apoptosis more robustly than imatinib, a currently used chordoma therapy. Furthermore, BKM120 significantly inhibited tumor growth in a subset of the xenograft models tested.

CONCLUSION

Targeted therapies, especially those inhibiting PI3K, display promising effects in multiple chordoma cell line and xenograft models. Nevertheless, the limited effects of PI3K, EGFR, and CDK targeting agents in other models reveal the presence of resistance mechanisms, which motivates future research to both identify biomarkers of response and develop combination therapies.

New Prospects for Molecular Targets for Chordomas

Chordomas are malignant, highly recurrent tumors of the midline skeleton that arise from the remnants of the notochord. The development of systemic therapy is critically important to ultimately managing this tumor. Several ongoing trials are attempting to use molecular targeted therapies for mutated pathways in recurrent and advanced chordomas and have shown promise. In addition, immunotherapies, including brachyury-directed vaccination and checkpoint inhibition, have also been attempted with encouraging results. This article discusses the major pathways that have been implicated in the pathogenesis of chordoma with an emphasis on molecular vulnerabilities that future therapies are attempting to exploit.

Chordoma: A Case Report and Review of Literature

Patient: Female, 68-year-old

Final Diagnosis: Chordoma

Symptoms: Hoarseness • neck pain • weakness

Medication: —

Clinical Procedure: —

Specialty: Oncology