Matrix biochemistry and cell biology of dedifferentiated chondrosarcomas

Patient-Derived Spheroid Culture Models Are Better Than Monolayer Models in Chondrosarcoma Research

Purpose

Chondrosarcoma (CSA) are mesenchymal tissue-derived bone tumors. CSA mainly occurs in older people. CSA has demonstrated resistance to chemotherapy and radiation; complete surgical removal with negative margins is the only treatment option. In the case of metastatic CSA, the chance of survival is meager. Since the conventional two-dimensional cell culture models failed to retain tumor characteristics, developing preclinical models mimicking the disease with the highest fidelity is paramount for personalized treatments.

Methods

In this study, we established spherical cultured cells as new models for CSA. First, we demonstrated that CSA cells could form spheroids when cultured in ultra-low attachment plates. Next, tissue samples from CSA patients were collected and processed into primary cells, which were subsequently cultured as primary spheroids. The growth rate of primary spheroids was monitored and the histology of mature spheroids were characterized. These primary spheroids were used in drug susceptibility studies where traditional doxorubicin therapy and our novel disulfiram-copper therapy were tested.

Results

Compared with conventional monolayer cultures, spheroids better recapitulated the features of the in vivo tumor in the aspect of the formation of extracellular matrix. In the drug susceptibility study, spheroids demonstrated high resistance to the classic therapies, suggesting that monolayer cultures may give false positive results. Therefore, using spheroids for drug research and development in the CSA field should provide more accurate results.

Conclusion

In summary, our study of primary CSA spheroids brought new insight into their chemoresistance and demonstrated its potential for personalized treatment of CSA in clinical medicine.

Dedifferentiated Chondrosarcoma: Diagnostic Controversies and Emerging Therapeutic Targets

PURPOSE OF REVIEW

The pathogenesis of dedifferentiated chondrosarcoma is controversial, and no genetic abnormality has consistently been identified in the disease. Focusing on the diagnostic challenges encountered in dedifferentiated chondrosarcoma, the following review aims at summarizing the tumor's active neoplastic pathways while highlighting therapeutic modalities that could potentially be explored to enhance patient survivorship.

RECENT FINDINGS

Owing to the challenging examination of small needle biopsy sampling as well as the disease's overlapping morphological and immunohistochemical features with other bone and soft-tissue sarcomas, the diagnosis of dedifferentiated chondrosarcoma can be problematic. While combined doxorubicin- and cisplatin-based regimens remain the first-line systemic chemotherapy in the disease, ~50% of tumors carry EXT1/2 or IDH1/2 mutations, advancing EXT or IDH inhibitors as potential alternative therapies, respectively. Despite systemic chemotherapy, dedifferentiated chondrosarcoma remains an aggressive tumor with dismal prognosis and limited survival. A multidisciplinary collaboration across multiple cancer centers is warranted to yield an accurate diagnosis, understand the disease's underlying pathogenesis, develop adequate treatment, and improve patient survivorship.

Dedifferentiated Chondrosarcoma from Molecular Pathology to Current Treatment and Clinical Trials

Dedifferentiated chondrosarcoma (DDCS) is a rare subtype of chondrosarcoma, a primary cartilaginous malignant neoplasm. It accounts for up to 1-2% of all chondrosarcomas and is generally associated with one of the poorest prognoses among all chondrosarcomas with the highest risk of metastasis. The 5-year survival rates range from 7% to 24%. DDCS may develop at any age, but the average presentation age is over 50. The most common locations are the femur, pelvis humerus, scapula, rib, and tibia. The standard treatment for localised disease is surgical resection. Most patients are diagnosed in unresectable and advanced stages, and chemotherapy for localised and metastatic dedifferentiated DDCS follows protocols used for osteosarcoma.

Clinical features and treatment outcomes of dedifferentiated and grade 3 chondrosarcoma: A multi-institutional study

Chondrosarcoma is the second most common primary malignant bone tumor. In this multicenter study, we sought to evaluate the (i) disease-specific survival (DSS) and disease-free survival (DFS), and (ii) prognostic factors in patients with dedifferentiated chondrosarcoma (DDCS) and grade 3 chondrosarcoma (G3CS) in Japan. We retrospectively investigated the treatment outcomes and prognostic factors in 62 patients with DDCS and 19 patients with G3CS at 15 institutions participating in the Japanese Musculoskeletal Oncology Group. We also clarified significant clinico-pathological factors for oncological outcomes. In surgery for primary lesions aimed at cure, a histologically negative margin (R0) was obtained in 93% (14/15) of patients with G3CS and 100% (49/49) of patients with DDCS. The 5-year DSS was 18.5% in patients with DDCS and 41.7% in patients with G3CS (P = 0.13). Local control was obtained in 80% (12/15) and 79.6% (39/49) of patients with G3CS and DDCS in the primary lesion after surgery with a wide surgical margin, respectively. In multivariate analysis, stage and no treatment/palliative treatment for the primary lesion were independent prognostic factors for DSS of DDCS, age and no treatment/palliative treatment for DSS of G3CS. The 5-year DFS rate was 22.8% in 26 patients with DDCS who did not receive adjuvant chemotherapy, and 21.4% in 14 patients who received adjuvant chemotherapy. The prognosis of DDCS remains poor, although R0 resection was performed in most cases. Effective and/or intensive chemotherapeutic regimens or agents should be considered or developed for patients with high-grade chondrosarcoma, particularly for those with DDCS.

Clonality analysis and IDH1 and IDH2 mutation detection in both components of dedifferentiated chondrosarcoma, implicated its monoclonal origin

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Dedifferentiated chondrosarcoma is composed of highly differentiated chondrosarcoma and highly malignant non-cartilaginous sarcomas with abruptly-defined.

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The question of whether the two components originated from the same archaeocyte has not yet been clarified.

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Clonality analysis showed that the two components were same X chromosome inactivation.

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The mutation states of IDH1 and IDH2 gene were consistent in the two components of a DDCS.

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We conclude that the two components of a DDCS originate from the same primitive cell.

Dedifferentiated chondrosarcoma (DDCS) is a highly malignant tumor that belongs to an uncommon subtype of chondrosarcoma with a poor prognosis. Microscopically, it is composed of highly differentiated chondrosarcoma and highly malignant noncartilaginous sarcomas with an abrupt interface. The question of whether the two components originated from the same archaeocyte has not yet been clarified. To further investigate this issue, DNA was separately extracted from the two components of the same patient. In total, 18 DDCS patients were analyzed. A portion of DNA samples from 9 female patients was used for clonality analysis. Another portion of DNA from 9 female and DNA from 9 male patients was used for isocitrate dehydrogenase 1(IDH1) and IDH2 gene mutation detection. The results of clonality analysis showed that the same X chromosome inactivation and consistent mutation states of the IDH1 and IDH2 genes in the two DDCS components. We conclude that the two DDCS components originate from the same primitive cell and that DDCS is monoclonal in origin.

Prognostic Factors in Dedifferentiated Chondrosarcoma: A Retrospective Analysis of a Large Series Treated at a Single Institution

Background

Dedifferentiated chondrosarcomas (DDCSs) are highly malignant tumors with a dismal prognosis and present a significant challenge in clinical management.

Methods

In an IRB approved retrospective protocol, we identified 72 patients with DDCS treated at our institution between 1993 and 2017 and reviewed clinicopathological characteristics, treatment modalities, and outcomes to analyze prognostic factors.

Results

Femur (44.4%), pelvis (22.2%), and humerus (12.5%) were most commonly involved sites. Twenty-three patients (31.9%) presented with distant metastasis, and 3 (4.2%) of them also had regional lymph node involvement. The median overall survival (OS) was 13.9 months. On multivariate analysis, pathological fracture, larger tumor size, lymph node involvement, metastasis at diagnosis, extraosseous extension, and undifferentiated pleomorphic sarcoma component correlated with worse OS, whereas surgical resection and chemotherapy were associated with improved OS. For progression-free survival (PFS), pathological fracture and metastasis at diagnosis showed increased risk, while chemotherapy was associated with decreased risk. Among patients who received chemotherapy, doxorubicin and cisplatin were significantly associated with improved PFS but not OS. Among patients without metastasis at diagnosis, 17 (34.7%) developed local recurrence. Thirty-one (63.3%) developed distant metastases at a median interval of 18.1 months. On multivariate analysis, R1/R2 resection was related with local recurrence, while macroscopic dedifferentiated component was associated with distant metastasis.

Conclusions

The prognosis of DDCS is poor. Complete resection remains a significant prognostic factor for local control. Chemotherapy with doxorubicin and cisplatin seems to have better PFS. More prognostic, multicenter trials are warranted to further explore the effectiveness of chemotherapy in selected DDCS patients.

Extraskeletal chondrosarcoma in the abdominal cavity of a cow

A 25-month-old female crossbred cow presented with astasia, emaciation, and stunted growth. Macroscopic examination revealed a large mass in the abdominal cavity, approximately 100 × 30 × 30 cm. Microscopic examination revealed that the mass consisted of multilobular mature and immature cartilaginous matrices with chondrocytic cells, surrounded by spindle to pleomorphic mesenchymal tumor cells. The cartilaginous matrices consisted of hyaline and elastic cartilages, as confirmed with Azan stain, and Victoria Blue and Van Gieson stain. Immunohistochemistry revealed that the chondrocytic and mesenchymal cells both expressed S-100. The tumor was diagnosed as an extraskeletal chondrosarcoma in the abdominal cavity of this cow.

Chondrosarcoma: A Rare Misfortune in Aging Human Cartilage? The Role of Stem and Progenitor Cells in Proliferation, Malignant Degeneration and Therapeutic Resistance

Unlike other malignant bone tumors including osteosarcomas and Ewing sarcomas with a peak incidence in adolescents and young adults, conventional and dedifferentiated chondrosarcomas mainly affect people in the 4th to 7th decade of life. To date, the cell type of chondrosarcoma origin is not clearly defined. However, it seems that mesenchymal stem and progenitor cells (MSPC) in the bone marrow facing a pro-proliferative as well as predominantly chondrogenic differentiation milieu, as is implicated in early stage osteoarthritis (OA) at that age, are the source of chondrosarcoma genesis. But how can MSPC become malignant? Indeed, only one person in 1,000,000 will develop a chondrosarcoma, whereas the incidence of OA is a thousandfold higher. This means a rare coincidence of factors allowing escape from senescence and apoptosis together with induction of angiogenesis and migration is needed to generate a chondrosarcoma. At early stages, chondrosarcomas are still assumed to be an intermediate type of tumor which rarely metastasizes. Unfortunately, advanced stages show a pronounced resistance both against chemo- and radiation-therapy and frequently metastasize. In this review, we elucidate signaling pathways involved in the genesis and therapeutic resistance of chondrosarcomas with a focus on MSPC compared to signaling in articular cartilage (AC).

In malignant cartilagenous tumors, immunohistochemical expression of procollagen PC1CP peptide is higher and that of PC2CP lower than in benign cartilaginous lesions

Few studies on oncogenesis of chondrosarcoma (CS) are available in the literature. Our previously published experimental evidence suggests that while the C-propeptide of procollagen Iα1 (PC1CP), a component of cartilage, favors tumor progression, the C-propeptide of procollagen IIα1 (PC2CP) exerts antitumor properties. In this study, we analyzed expression of PC1CP and PC2CP by immunohistochemistry in a series of enchondromas and CS. Our retrospective series consisted of 88 cases, including 43 CSs, 34 enchondromas and 11 nontumor samples. Immunohistochemical staining for PC1CP and PC2CP was evaluated in the cytoplasm and in the extracellular matrix (ECM). Diffuse staining for PC1CP in ECM was significantly more frequent in tumor than in nontumor samples (32 % vs. 0 %; p = 0.03), and in CSs than in enchondromas (44 vs. 18 %; p = 0.02). ECM semiquantitative score was higher in tumors than in nontumor samples (p < 0.005) and higher in CSs than in enchondromas (p = 0.05). Staining for PC2CP in ECM was more frequently found in enchondromas than in CSs (59 vs. 33 %; p = 0.02). ECM semiquantitative score was higher in enchondromas than in CSs (p = 0.02). Diffuse staining for PC1CP in combination with absence of staining for PC2CP had 94 % specificity for CS but with a sensitivity of only 35 %. Expression of neither PC1CP nor PC2CP correlated with recurrence-free survival or occurrence of metastases. In conclusion, we show that the expression of PC1CP is higher and that of PC2CP lower in malignant cartilaginous tumors. These results support an oncogenic role of PC1CP and anti-oncogenic property of PC2CP in cartilaginous tumors.

The molecular pathogenesis of dedifferentiated chondrosarcoma

Dedifferentiated chondrosarcomas are cartilaginous tumors that consist of two distinguishable components, a lowgrade chondrosarcoma (chondrogenic) component and a highgrade dedifferentiated (anaplastic) component. The tumor cells in both components seem to originate from a single precursor, but there are a substantial number of genetic alterations in the anaplastic component. The underlying mechanism of dedifferentiation is unknown, but cell cycle regulators p16, p53 and retinoblastoma appear to have important roles in tumor development and dedifferentiation. In this article, molecular pathogenesis of dedifferentiated chondrosarcomas is reviewed.