Establishment and characterization of cell line TNMY1 derived from human malignant fibrous histiocytoma

Neurotensin receptor 1 is a new therapeutic target for human undifferentiated pleomorphic sarcoma growth

Undifferentiated pleomorphic sarcoma (UPS) is the second most common soft tissue sarcoma. For patients with unresectable or metastatic disease, chemotherapies are considered, but in many cases they are not curative. There is a need to identify specific molecular dysregulations that can be therapeutic targets. We focused on neurotensin receptor 1 (NTSR1), which belongs to the G-protein-coupled receptor. NTSR1 expression was upregulated in specimens from patients with UPS. Real-time polymerase chain reaction showed that expression of NTSR1 messenger RNA was 5- to 7-fold increased in UPS cells compared with myoblasts. Western blot showed a high expression of NTSR1 protein in UPS cell lines. Knockdown of NTSR1 prevented UPS cell proliferation and invasion. We confirmed that SR48692, an inhibitor of NTSR1, exhibited antitumor activities in UPS cells. The combination index showed that SR48692 and standard chemotherapeutic drugs prevented UPS cell proliferation synergistically. Mouse xenograft models showed that SR48692 inhibited extracellular signal-regulated kinase phosphorylation and enhanced the response to standard chemotherapeutic drugs. Inhibition of NTSR1 improved the effect of standard chemotherapeutic drugs for UPS. SR48692 may be a new drug for targeted UPS therapy.

The histone deacetylase inhibitor LBH589 inhibits undifferentiated pleomorphic sarcoma growth via downregulation of FOS-like antigen 1

Undifferentiated pleomorphic sarcoma (UPS) is the second most frequent soft tissue sarcoma. Because of its resistance to chemotherapy, UPS patients are treated with surgical resection and complementary radiotherapy. However, since standard chemotherapy has not been established, unresectable or metastatic cases result in a poor prognosis. Therefore, the identification of a more effective therapy for UPS patients is needed. The development and progression of malignant tumors involve epigenetic alterations, and histone deacetylases (HDAC) have become a promising chemotherapeutic target. In this study, we investigated the potential effects and mechanisms of an HDAC inhibitor, LBH589, in UPS cells. We confirmed that LBH589 exhibits potent antitumor activities in four human UPS cell lines (GBS-1, TNMY-1, Nara-F, and Nara-H) and IC₅₀ values ranged from 7 to 13 nM. A mouse xenograft model showed that LBH589 treatment effectively suppressed tumor growth. FACS analysis showed that LBH589 induced apoptosis and G2/M cell cycle arrest. Among apoptosis-related proteins, the expressions of Bcl-2 and Bcl-xL were decreased and the expression of Bak and Bim increased. Among cell cycle-related proteins, reductions of CDK1, p-CDK1, cyclin B1, Aurora A, and Aurora B were observed after LBH589 treatment. RNA microarray identified the FOS-like antigen 1 (FOSL1) gene as a downregulated gene in response to LBH589 in UPS cells. While knockdown of FOSL1 decreased UPS cell proliferation, overexpression induced cell proliferation. Our results show that LBH589 could be a promising chemotherapeutic agent in the treatment of UPS and downregulation of the FOSL1 gene could be the new molecular target of UPS treatment.

Establishment and proteomic characterization of a novel cell line, NCC-UPS2-C1, derived from a patient with undifferentiated pleomorphic sarcoma

Undifferentiated pleomorphic sarcoma (UPS) is an aggressive mesenchymal malignancy requiring novel therapeutic approaches to improve clinical outcome. Patient-derived cancer cell lines are an essential tool for investigating molecular mechanisms underlying cancer initiation and development; however, there is a lack of patient-derived cell lines of UPS available for research. The objective of this study was to develop a patient-derived cell model of UPS. A cell line designated NCC-UPS2-C1 was established from the primary tumor tissue of an 84-yr-old female patient with UPS. The short tandem repeat pattern of NCC-UPS2-C1 cells was identical to that of the original tumor and distinct from that of any other cell lines deposited in public cell banks. NCC-UPS2-C1 cells were maintained as a monolayer culture for over 80 passages during 30 mo and exhibited spindle-like morphology, continuous growth, and ability for spheroid formation and invasion. Proteomic profiling using mass spectrometry and functional treemap analysis revealed that the original tumor and the derived NCC-UPS2-C1 cells had similar but distinct protein expression patterns. Our results indicate that a novel UPS cell line was successfully established and could be used to study UPS development and effects of anti-cancer drugs. However, the revealed difference between proteomes of the original tumor and NCC-UPS2-C1 cells should be further investigated to determine the appropriate applications of this cell line in UPS research.

Characterization of the new human pleomorphic undifferentiated sarcoma TP53-null cell line mfh-val2

Pleomorphic undifferentiated sarcoma (PUS), also called malignant fibrous histiocytoma, is a soft tissue sarcoma which occurs predominantly in the extremities. Its origin is a poorly defined mesenchymal cell, which derives to histiocytic and fibroblastic cells. The patient, a 58 year-old man, presented a lesion located in the forearm composed by spindle cells and multinucleated giant cells, which expressed vimentin and adopted a histological pattern formed by irregular-swirling fascicles. Cells were cultured in vitro and a new cell line was established. We characterized this new cell line by histological analyses, cytogenetics (using G-bands and spectral karyotype technique) and cytometric analyses. Cells were grown in culture for more than 100 passages. They had elongated or polygonal morphology. The cells presented a saturation rate of 70,980 cells/cm², a plating efficiency of 21.5% and a mitotic index of 21 mitoses per field. The cell line was tumorigenic in nude mice. The ploidy study using flow cytometry revealed an aneuploid peak with a DNA index of 1.43. A side population was detected, demonstrating the presence of stem and progenitor cells. Cytogenetics showed a hypotriploid range with many clonal unbalanced rearrangements. Loss of p53 gene was evidenced by MLPA. We describe, for the first time, the characterization of a new human PUS TP53-null cell line called mfh-val2. Mfh-val2 presents a wide number of applications as a TP53-null cell line and a great interest in order to characterize genetic alterations influencing the oncogenesis or progression of PUS and to advance in the biological investigation of this tumor.

Xenograft models for undifferentiated pleomorphic sarcoma not otherwise specified are essential for preclinical testing of therapeutic agents

Undifferentiated pleomorphic sarcoma not otherwise specified belongs to the heterogeneous group of soft tissue tumors. It is preferentially located in the upper and lower extremities of the body, and surgical resection remains the only curative treatment. Preclinical animal models are crucial to improve the development of novel chemotherapeutic agents for the treatment of undifferentiated pleomorphic sarcoma. However, this approach has been hampered by the lack of reproducible animal models. The present study established two xenograft animal models generated from stable non-clonal cell cultures, and investigated the difference in chemotherapeutic effects on tumor growth between undifferentiated pleomorphic sarcoma in vivo and in vitro. The cell cultures were generated from freshly isolated tumor tissues of two patients with undifferentiated pleomorphic sarcoma. For the in vivo analysis, these cells were injected subcutaneously into immunodeficient mice. The mice were monitored for tumor appearance and treated with the most common or innovative chemotherapeutic agents available to date. Furthermore, the same drugs were administered to in vitro cell cultures. The most effective tumor growth inhibition in vitro was observed with doxorubicin and the histone deacetylase inhibitor suberoylanilide hydroxamic acid (SAHA), also known as vorinostat. In the in vivo xenograft mouse model, the combination of doxorubicin and the tyrosine kinase inhibitor pazopanib induced a significant tumor reduction. By contrast, treatment with vorinostat did not reduce the tumor growth. Taken together, the results obtained from drug testing in vitro differed significantly from the in vivo results. Therefore, the novel and reproducible xenograft animal model established in the present study demonstrated that in vivo models are required to test potential chemotherapeutic agents for the treatment of undifferentiated pleomorphic sarcoma prior to clinical use, since animal models are more similar to humans, compared with in vitro cell cultures.

Antitumor effect of YM155, a novel small-molecule survivin suppressant, via mitochondrial apoptosis in human MFH/UPS

Survivin is a member of the inhibitor of apoptosis family, which is known to inhibit mitochondrial apoptosis. Survivin is highly expressed in cancers and plays an important role in cancer cell survival, and increased survivin expression is an unfavorable prognostic marker in cancer patients. YM155, a novel small-molecule survivin suppressant, selectively suppresses survivin expression, resulting in the induction of apoptosis in various malignancies. However, the roles of survivin in human malignant fibrous histiocytoma/undifferentiated pleomorphic sarcoma (MFH/UPS) have not been studied. In the present study, we examined survivin expression in human musculoskeletal tumor tissues, and the effect of survivin inhibition by siRNA or YM155 on apoptotic activity in human MFH/UPS cell lines. In tumor tissues, mRNA expression of survivin was significantly higher in MFH/UPS samples than in benign schwannomas. Moreover, in vitro studies revealed that both survivin siRNA and YM155 suppressed survivin expression and inhibited MFH/UPS cell proliferation in a dose- and a time-dependent manner. Further, the numbers of apoptotic cells significantly increased with YM155 treatment. In vivo, tumor volume in YM155-treated groups was significantly reduced without significant bodyweight loss. Increased apoptotic activity along with decreased survivin expression was also observed in YM155-treated tumors. The findings in this study strongly suggest that survivin suppressants, including YM155, contribute to the suppression of human MFH/UPS cell growth via promoting mitochondrial apoptosis, and that survivin may be a potent therapeutic target for the novel treatment of human MFH/UPS.

Transcutaneous application of CO2 enhances the antitumor effect of radiation therapy in human malignant fibrous histiocytoma

Sarcomas are relatively resistant because of hypoxia. We previously demonstrated that the transcutaneous CO(2) therapy reduced hypoxic conditions in human malignant fibrous histiocytoma (MFH). Therefore, we hypothesized that transcutaneous CO(2) therapy could enhance the antitumor effect of radiation therapy in human MFH. Our purpose was to evaluate the effects of transcutaneous CO(2) therapy on the antitumor efficacy of X-ray irradiation using MFH. First, in an in vitro study, we assessed apoptotic activity and reactive oxygen species (ROS) production using flow cytometric and immunoblot analysis at 24 h after X-ray irradiation under three different oxygen conditions (normoxic, reoxygenated and hypoxic). In addition, in the in vivo study, 24 male athymic BALB/c nude mice with MFH tumors that were inoculated in the dorsal subcutaneous area were randomized into four groups: control, CO(2), X-ray irradiation and combination (CO(2) and X-ray irradiation). Treatments were performed twice weekly for 2 weeks, four times in total. Tumor volume was calculated. All tumors were excised and apoptotic activity, ROS production, related proteins and HIF-1α expression were assessed using flow cytometric and immunoblot analysis. The in vitro study revealed that X-ray irradiation induced increased apoptosis and ROS production in MFH cells under normoxic and reoxygenated conditions relative to hypoxic conditions (P<0.01). In the in vivo study, tumor volume in the combination group was reduced to 28, 42 and 47% of that in the control, CO(2), and X-ray groups, respectively (P<0.05). Apoptotic activity and ROS production in the combination group were strongly increased with decreasing HIF-1α expression relative to the control, CO(2) and X-ray groups. The transcutaneous CO(2) system enhanced the antitumor action of X-ray irradiation and could be a novel therapeutic tool for overcoming radio-resistance in human malignancies.

Regulation of mitochondrial proliferation by PGC-1α induces cellular apoptosis in musculoskeletal malignancies

A number of studies have reported that decreased mitochondrial numbers are linked with neoplastic transformation and/or tumor progression, including resistance to apoptosis. Peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α) is a multi-functional transcriptional coactivator that regulates the activities of multiple nuclear receptors and transcriptional factors involved in mitochondrial biogenesis. In this study, we observed that the number of mitochondria in sarcoma tissues, such as osteosarcoma and malignant fibrous histiocytoma, is significantly lower than that in normal muscle tissue or benign tumors and that increasing the number of mitochondria by PGC-1α overexpression induces mitochondrial apoptosis in human sarcoma cell lines. The findings suggest that decreased mitochondrial numbers may contribute to musculoskeletal tumor progression and that regulation of mitochondrial numbers by PGC-1α could be a potent therapeutic tool for human malignancies.

'Decoy' and 'non-decoy' functions of DcR3 promote malignant potential in human malignant fibrous histiocytoma cells

Decoy receptor 3 (DcR3) is a soluble secreted protein that belongs to the tumor necrosis factor receptor (TNFR) superfamily. DcR3 inhibits the Fas ligand (FasL)/Fas apoptotic pathway by binding to FasL, competitively with Fas receptor. Previous studies have reported that overexpression of DcR3 has been detected in various human malignancies and that DcR3 functions as a ‘decoy’ for FasL to inhibit FasL-induced apoptosis. In addition, recent studies have revealed that DcR3 has ‘non-decoy’ functions to promote tumor cell migration and invasion, suggesting that DcR3 may play important roles in tumor progression by decoy and non-decoy functions. We have previously reported that overexpression of DcR3 was observed in human malignant fibrous histiocytoma (MFH), however, the roles of DcR3 in MFH have not been studied. In the present study, to elucidate the roles of DcR3 in tumor progression of MFH, we examined the effects of DcR3 inhibition on cell apoptosis, migration and invasion in human MFH cells. siRNA knockdown of DcR3 enhanced the FasL-induced apoptotic activity and significantly decreased cell migration and invasion with a decrease in the activation of phosphatidylinositol 3 kinase (PI3K)/Akt and matrix metalloproteinase (MMP)-2. The findings in this study strongly suggest that DcR3 plays important roles in tumor progression of human MFH by decoy as well as non-decoy functions and that DcR3 may serve as a potent therapeutic target for human MFH.

Establishment of a new human pleomorphic malignant fibrous histiocytoma cell line, FU-MFH-2: molecular cytogenetic characterization by multicolor fluorescence in situ hybridization and comparative genomic hybridization

Background

Pleomorphic malignant fibrous histiocytoma (MFH) is one of the most frequent malignant soft tissue tumors in adults. Despite the considerable amount of research on MFH cell lines, their characterization at a molecular cytogenetic level has not been extensively analyzed.

Methods and results

We established a new permanent human cell line, FU-MFH-2, from a metastatic pleomorphic MFH of a 72-year-old Japanese man, and applied multicolor fluorescence in situ hybridization (M-FISH), Urovysion™ FISH, and comparative genomic hybridization (CGH) for the characterization of chromosomal aberrations. FU-MFH-2 cells were spindle or polygonal in shape with oval nuclei, and were successfully maintained in vitro for over 80 passages. The histological features of heterotransplanted tumors in severe combined immunodeficiency mice were essentially the same as those of the original tumor. Cytogenetic and M-FISH analyses displayed a hypotriploid karyotype with numerous structural aberrations. Urovysion™ FISH revealed a homozygous deletion of the p16^INK4A locus on chromosome band 9p21. CGH analysis showed a high-level amplification of 9q31-q34, gains of 1p12-p34.3, 2p21, 2q11.2-q21, 3p, 4p, 6q22-qter, 8p11.2, 8q11.2-q21.1, 9q21-qter, 11q13, 12q24, 15q21-qter, 16p13, 17, 20, and X, and losses of 1q43-qter, 4q32-qter, 5q14-q23, 7q32-qter, 8p21-pter, 8q23, 9p21-pter, 10p11.2-p13, and 10q11.2-q22.

Conclusion

The FU-MFH-2 cell line will be a particularly useful model for studying molecular pathogenesis of human pleomorphic MFH.

Establishment of a nude mouse transplantable model of a human malignant fibrous histiocytoma of the mandible with high metastatic potential to the lung

Malignant fibrous histiocytoma (MFH) is one of the highest-grade sarcomas arising in bone and soft tissue. Its prognosis is poor because of chemoresistance and high metastatic potential to various organs. Few cases arising of MFH of the mandible or oral cavity have been documented. We established a tumor line in nude mice (MFH-N), which was derived from human MFH of the mandible and examined the characteristics of this tumor line. Histologically, MFH-N was identical to the original tumor and showed a storiform-pleomorphic pattern, but had low metastatic potential. Immunohistochemically, both the original and xenografted tumors expressed vimentin, S-100, alpha-SMA, and histiocytic marker CD68. Lysozyme was expressed by the original tumor, but only sporadically by the xenografted tumor. RT-PCR analysis demonstrated human beta-actin in this tumor line, indicating the human origin. In a parallel experiment, we established a new MFH cell line (MFH-NC) from MFH-N. Tumor cells inoculated into the flanks and submandibular region of nude mice developed into tumors histologically similar to MFH-N and the original tumor; multiple lung metastases were detected approximately 5 months after inoculation. The expression levels of various metastasis-related molecules differed between MFH-N and MFH-NC on Western blotting. In MFH-NC, the expressions of MMP7, MMP9, MT1-MMP, CXCR4, COX-2 and integrin alpha4 were up-regulated, while those of MMP2 and TIMP1 were down-regulated. Expression of TIMP2, integrinalphaL and sialyl lewis X were not detected in either line. Our findings suggest that the MFH-N tumor line transplantable in nude mice is a useful model for studying the biological behavior of MFH.

Establishment and characterization of a novel myxofibrosarcoma cell line

We established a novel human myxofibrosarcoma cell line NMFH-1 and analyzed it with spectral karyotyping and comparative genomic hybridization (CGH). NMFH-1 cells are composed of two different types of cells, small, spindle-shaped mononuclear cells and bizarre multinucleated giant cells, which were maintained in vitro over 200 passages. Xenografted tumor showed typical features of myxofibrosarcoma, which included bizarre multinucleated giant cells. Cytogenetic analyses revealed complex abnormalities, including a t(17;22)(q2?2;q13), which has been found in dermatofibrosarcoma protuberans. Subsequent reverse-transcription polymerase chain reaction revealed that the cell line did not have the COL1A1-PDGFB gene fusion. Significant gains of the 1q12 approximately q23 and 8q13 approximately qter regions and loss of the 9p21 approximately pter and 13q12 regions often found in MFH were observed by CGH analysis. We investigated the origin of multinucleated giant cells in xenografted tumor through DNA in situ hybridization. In this system, the human-specific Alu sequence and the mouse L1 sequence were used as specific cell markers of identity. In situ hybridization revealed neoplastic proliferation of the multinucleated giant cells of human origin.

Establishment of a new human malignant fibrous histiocytoma cell line, FU-MFH-1: cytogenetic characterization by comparative genomic hybridization and fluorescence in situ hybridization

Although a number of malignant fibrous histiocytoma (MFH) cell lines have been reported, their characterization at a molecular cytogenetic level has not been fully established. In this study, we established a new human cell line, designated as FU-MFH-1, from a storiform-pleomorphic MFH arising in the retroperitoneum of a 61-year-old woman, and applied comparative genomic hybridization (CGH) and fluorescence in situ hybridization (FISH) with chromosome painting probes for the characterization of chromosome alterations. FU-MFH-1 cells were spindle, round, or polygonal in shape with oval nuclei, and were maintained continuously in vitro for over 50 passages for more than 12 months. G-banding analysis was performed and FU-MFH-1 revealed a complex karyotype with an abnormal chromosome 19 containing a homogeneously staining region (hsr). CGH analysis showed a high-level amplification of 12q13-->q21. The high-level amplification detected by CGH was refined by FISH. These results showed that the hsr was composed of amplified DNA sequences from 12q. Our study emphasizes the usefulness of CGH as a powerful tool for chromosomal localization of amplified sequences. The FU-MFH-1 cell line should be useful for biologic and molecular pathogenetic investigations of human MFH.