Effects of bone marrow mesenchymal stem cell-conditioned medium on the proliferation and migration of liposarcoma cells

INTRODUCTION

Liposarcoma constitutes a prevalent subtype of soft tissue sarcoma, represents approximately 20% of all sarcomas. However, conventional chemotherapeutic agents have shown restricted effectiveness in treating liposarcoma patients. Accumulating evidence indicates that mesenchymal stem cells (MSCs) have the characteristic of migration to tumor site, promote or suppress tumors. How human bone marrow mesenchymal stem cells (BMSCs) contribute to liposarcoma phenotype remains poorly understood. This study aims to investigate the effects of human bone marrow mesenchymal stem cell-conditioned medium (BMSC-CM) on the proliferation and migration of liposarcoma cell lines 93T449 and SW872, as well as explore potential underlying mechanisms of BMSC-CM action on these cells.

MATERIALS AND METHODS

We transfected BMSCs with lentiviral constructs to knock down the transcriptional co-activator Yes-associated protein 1 (YAP1), conditioned medium (CM) obtained from BMSCs and shYAP1-BMSC, respectively. Liposarcoma cell lines 93T449 and SW872 were co-cultured with BMSC-CM or shYAP1-BMSC-CM. Cell proliferation ability was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. Cell apoptosis was evaluated using flow cytometric assay. A wound healing assay was used to analyze cell migration. The expression levels of YAP1, Bcl-2, and matrix metalloproteinase-2 (MMP-2) were determined by western blot assay.

RESULTS

Co-culturing liposarcoma cell lines 93T449 and SW872 with BMSC-CM promoted tumor cell proliferation, while shYAP1-BMSC-CM significantly inhibited cell viability and migration, induced apoptosis, and downregulated Bcl-2 and MMP-2 expression.

CONCLUSIONS

These findings provide new insights into the impact of BMSC-CM on liposarcoma and suggest its possible involvement in liposarcoma cell growth.

Clozapine suppresses NADPH oxidase activation, counteracts cytosolic H2O2, and triggers early onset mitochondrial dysfunction during adipogenesis of human liposarcoma SW872 cells

Long-term treatment of schizophrenia with clozapine (CLZ), an atypical antipsychotic drug, is associated with an increased incidence of metabolic disorders mediated by poorly understood mechanisms. We herein report that CLZ, while slowing down the morphological changes and lipid accumulation occurring during SW872 cell adipogenesis, also causes an early (day 3) inhibition of the expression/nuclear translocation of CAAT/enhancer-binding protein β and peroxisome proliferator-activated receptor γ. Under the same conditions, CLZ blunts NADPH oxidase-derived reactive oxygen species (ROS) by a dual mechanism involving enzyme inhibition and ROS scavenging. These effects were accompanied by hampered activation of the nuclear factor (erythroid-derived2)-like 2 (Nrf2)-dependent antioxidant responses compared to controls, and by an aggravated formation of mitochondrial superoxide. CLZ failed to exert ROS scavenging activities in the mitochondrial compartment but appeared to actively scavenge cytosolic H2O2 derived from mitochondrial superoxide. The early formation of mitochondrial ROS promoted by CLZ was also associated with signs of mitochondrial dysfunction. Some of the above findings were recapitulated using mouse embryonic fibroblasts. We conclude that the NADPH oxidase inhibitory and cytosolic ROS scavenging activities of CLZ slow down SW872 cell adipogenesis and suppress their Nrf2 activation, an event apparently connected with increased mitochondrial ROS formation, which is associated with insulin resistance and metabolic syndrome. Thus, the cellular events characterised herein may help to shed light on the more detailed molecular mechanisms explaining some of the adverse metabolic effects of CLZ.

Notch signaling regulates a metabolic switch through inhibiting PGC-1α and mitochondrial biogenesis in dedifferentiated liposarcoma

Human dedifferentiated liposarcoma (DDLPS) is a rare but lethal cancer with no driver mutations being identified, hampering the development of targeted therapies. We and others recently reported that constitutive activation of Notch signaling through overexpression of the Notch1 intracellular domain (NICDOE) in murine adipocytes leads to tumors resembling human DDLPS. However, the mechanisms underlying the oncogenic functions of Notch activation in DDLPS remains unclear. Here, we show that Notch signaling is activated in a subset of human DDLPS and correlates with poor prognosis and expression of MDM2, a defining marker of DDLPS. Metabolic analyses reveal that murine NICDOE DDLPS cells exhibit markedly reduced mitochondrial respiration and increased glycolysis, mimicking the Warburg effect. This metabolic switch is associated with diminished expression of peroxisome proliferator-activated receptor gamma coactivator 1α (Ppargc1a, encoding PGC-1α protein), a master regulator of mitochondrial biogenesis. Genetic ablation of the NICDOE cassette rescues the expression of PGC-1α and mitochondrial respiration. Similarly, overexpression of PGC-1α is sufficient to rescue mitochondria biogenesis, inhibit the growth and promote adipogenic differentiation of DDLPS cells. Together, these data demonstrate that Notch activation inhibits PGC-1α to suppress mitochondrial biogenesis and drive a metabolic switch in DDLPS.

Growth-Suppressive and Apoptosis-Inducing Effects of Tetrandrine in SW872 Human Malignant Liposarcoma Cells via Activation of Caspase-9, Down-Regulation of XIAP and STAT-3, and ER Stress

Liposarcoma is a rare and heterogeneous soft tissue malignant tumor and has a significant impact on mortality with a poor prognosis. To date, there is no effective treatment for liposarcoma, whereas surgical resection is only the gold treatment with numerous adverse effects. Here we investigated whether tetrandrine inhibits the growth of SW872 human malignant liposarcoma cells. Of note, tetrandrine at 10 μM vastly inhibited growth and induced apoptosis, as evidenced by increased nuclear DNA fragmentation and sub-G1 population of SW872 cells. Mechanistically, treatment with tetrandrine led to activation of caspase-9/3 in SW872 cells, and z-VAD-fmk, a pan-caspase inhibitor, attenuated the tetrandrine-induced apoptosis and growth suppression in SW872 cells. In addition, tetrandrine treatment resulted in down-regulation of XIAP andSTAT-3 in SW872 cells, and importantly knockdown of STAT-3 caused a significant reduction of the cell survival. Tetrandrine also had abilities to up-regulate not only the expression of GRP78 and ATF-4 but also the phosphorylation of eIF-2α in SW872 cells. In summary, these results demonstrated that tetrandrine has strong growth-suppressive and apoptosis-inducing effects on SW872 cells, which are mediated through control of the intrinsic caspase pathway, down-regulation of XIAP and STAT-3, and triggering ER stress.

Clinical Application of Chromosome Microarray Analysis in the Diagnosis of Lipomatous Tumors

Well-differentiated liposarcoma/atypical lipomatous tumor (WDLS/ALT) and dedifferentiated liposarcoma (DDLS) have characteristic supernumerary ring and giant marker chromosomes involving the chromosomal region 12q13-15 which contains MDM2 (12q15), CDK4 (12q14.1), HMGA2 (12q14.3), YEATS4 (12q15), CPM (12q15), and FRS2 (12q15). Detecting MDM2 amplification by fluorescence in situ hybridization (FISH) is considered to be the gold standard for the diagnosis of WDLS/ALT and DDLS. In this study, formalin fixed paraffin embedded clinical specimens (16 liposarcomas and 19 benign lipomatous tumors) were used to detect MDM2 amplification and other chromosomal alterations in WDLS/ALT and DDLS by single nucleotide polymorphism-based chromosome microarray (CMA). All 16 liposarcomas showed MDM2 amplification with a MDM2/cep12 ratio from 2.4 to 8.4 by CMA. Ten (62.5%) of these cases had CDK4/cep12 ratio ≥2.0. All the cases without CDK4 amplification were from the thigh. The MDM2/cep12 ratio of all the benign lipomatous tumors (19/19) was within the normal limits. Twenty-one of the 35 benign lipomatous tumors and liposarcomas were also tested for MDM2 amplification by FISH. All the FISH results were consistent with the CMA results (100%). Along with MDM2 amplification, all 16 liposarcomas (100%) also showed amplification of YEATS4, CPM and FRS2. Only 11 of 16 (69%) cases showed HMGA2 amplification. In conclusion, this study demonstrated that CMA on routine formalin fixed paraffin embedded tissue is a sensitive and specific clinical test for detection of MDM2 gene amplification. Moreover, CMA allows simultaneous detection of genomic changes of interest including CDK4 and others, which provides enriched information for diagnosing lipomatous tumors.

Selinexor versus doxorubicin in dedifferentiated liposarcoma PDXs: evidence of greater activity and apoptotic response dependent on p53 nuclear accumulation and survivin down-regulation

BACKGROUND

Dedifferentiated liposarcoma (DDLPS), a tumor that lacks effective treatment strategies and is associated with poor outcomes, expresses amplified MDM2 in the presence of wild-type p53. MDM2 ubiquitination of p53 facilitates its XPO1-mediated nuclear export, thus limiting p53 tumor suppressor functions. Consequently, nuclear export is a rational target in DDLPS. We directly compared the antitumor activity of the first-in class XPO1 inhibitor selinexor and doxorubicin, the standard front-line therapy in sarcomas, in DDLPS patient-derived xenografts (PDXs) and primary cell lines.

METHODS

Drug activity was assessed in three PDXs (and two corresponding cell lines) established from the dedifferentiated component of primary untreated retroperitoneal DDLPS with myogenic (N = 2) and rhabdomyoblastic (N = 1) differentiation from patients who underwent surgery. These models were marked by amplification of MDM2, CDK4 and HMGA2 genes.

RESULTS

Selinexor was moderately active in the three PDXs but achieved greater tumor response compared to doxorubicin (maximum tumor volume inhibition: 46-80 % vs. 37-60 %). The PDX harboring rhabdomyoblastic dedifferentiation showed the highest sensitivity to both agents. PDX response to selinexor and doxorubicin was not associated with the extent of MDM2 and CDK4 gene amplification. Interestingly, the most chemosensitive PDX model showed the lowest extent of HMGA2 amplification. Selinexor was also more efficient than doxorubicinin in inducing an apoptotic response in PDXs and cell lines. Consistently, an increased nuclear accumulation of p53 was seen in all selinexor-treated models. In addition, a time-dependent decrease of survivin expression, with an almost complete abrogation of the cytoplasmic anti-apoptotic pool of this protein, was observed as a consequence of the decreased acetylation/activation of STAT3 and the increased ubiquitination of nuclear survivin.

CONCLUSIONS

Selinexor showed a moderate antitumor activity in three DDLPS PDXs, which was, however, consistently higher than doxorubicin across all different models regardless the extent of MDM2 amplification and the histological differentiation. The depletion of survivin protein seems to significantly contribute to the induction of apoptosis through which selinexor exerts its antitumor activity.

Extraordinarily long-inactive solitary fibrous tumor transformed to produce big insulin-like growth factor-2, leading to hypoglycemia and rapid liposarcoma growth: a case report

BACKGROUND

A high-molecular-weight form of insulin-like growth factor-2 (IGF-2), known as "big" IGF-2, is occasionally produced by various tumor types, leading to hypoglycemia. Although solitary fibrous tumor (SFT) is a rare mesenchymal neoplasm, it has been estimated that 4-6% of SFT patients develop hypoglycemia due to circulating big IGF-2. The mean time elapsed from tumor detection until the onset of hypoglycemia is reportedly less than one year (8.5 ± 1.9 months).

CASE PRESENTATION

A 68-year-old man was hospitalized for exacerbation of recurring hypoglycemic episodes. He had been diagnosed with an SFT 17 years before the onset of hypoglycemia, and the SFT had already been very large at that time. The tumor, which was non-resectable and refractory to chemotherapies, had slowly increased in size since the initial diagnosis. Half a year before the hypoglycemic episodes manifested, another tumor, adjacent to the left kidney, was newly identified. Fluorodeoxyglucose positron emission tomography-computed tomography scanning, revealed the left peri-renal tumor to show much higher fluorodeoxyglucose uptake than the preexisting SFT, suggesting that it was unlikely to be a metastasis from the SFT. Abundant serum big IGF-2 was detected by western immunoblot analysis, indicating it to be the cause of the hypoglycemia. Since the 17 years between SFT detection and the onset of IGF-2-induced hypoglycemia was an extremely long period as compared with those in previous reports, we initially suspected that the new, peri-renal tumor had produced big IGF-2, but transcatheter arterial embolization of its feeding arteries did not suppress hypoglycemia. Notably, by measuring the tumor volume doubling time, the peri-renal tumor growth was shown to be markedly accelerated in parallel with exacerbation of the hypoglycemia. The patient died of heart failure 21 months after the onset of hypoglycemia. Unexpectedly, autopsy revealed that big IGF-2 had been produced only by the preexisting SFT, not the peri-renal tumor, and that the peri-renal tumor was a dedifferentiated liposarcoma.

CONCLUSIONS

We should keep in mind that even a long-inactive SFT can undergo transformation to produce big IGF-2, which then acts on both insulin and IGF-1 receptors, possibly leading to both hypoglycemia and the development/growth of another tumor, respectively.

Anti-Survival and Pro-Apoptotic Effects of 6-Shogaol on SW872 Human Liposarcoma Cells via Control of the Intrinsic Caspase Pathway, STAT-3, AMPK, and ER Stress

Notably, 6-Shogaol, a bioactive natural substance, has anticancer effects on many types of tumors. Up to date, the anticancer effect and mode of action of 6-Shogaol on liposarcoma are not known. In this study, we investigated whether 6-Shogaol inhibits the growth of SW872 and 93T449 cells, two different human liposarcoma cell lines. Of note, 6-Shogaol inhibited the growth of SW872 and 93T449 cells without affecting that of normal 3T3-L1 preadipocytes. Specifically, 6-Shogaol further induced the apoptosis of SW872 cells, as evidenced by nuclear DNA fragmentation, increased sub G1 population, activation of the intrinsic caspase pathway, and PARP cleavage. However, pretreatment with either z-VAD-fmk, a pan-caspase inhibitor, or N-acetylcysteine, an antioxidant, attenuated the 6-Shogaol’s growth-suppressive and apoptosis-inducing effects on SW872 cells. Moreover, 6-Shogaol activated AMPK while inhibited STAT-3 in SW872 cells, and siRNA-based genetic silencing of AMPK or STAT-3 considerably blocked the growth-suppressive and apoptotic response of 6-Shogaol to SW872 cells. Moreover, 6-Shogaol also upregulated the expression and phosphorylation of GRP-78, eIF-2α, ATF4, and CHOP, known ER stress markers, in SW872 cells, illustrating the induction of ER stress. These findings collectively demonstrate that 6-Shogaol has strong antigrowth and proapoptotic effects on SW872 cells through regulation of the intrinsic caspase pathway, oxidative stress, STAT-3, AMPK, and ER stress.

A review of retroperitoneal liposarcoma genomics

Retroperitoneal liposarcomas are rare tumours that carry a poorer prognosis than their extremity counterparts. Within their subtypes - well differentiated (WDL), dedifferentiated (DDL), myxoid (MLS) and pleomorphic (PLS) - they exhibit a diverse genomic landscape. With recent advances in next generation sequencing, the number of studies exploring this have greatly increased. The recent literature has deepened our understanding of the hallmark MDM2/CDK4 amplification in WDL/DDL and addressed concerns about toxicity and resistance when targeting this. The FUS-DDIT3 fusion gene remains the primary focus of interest in MLS with additional potential targets described. Whole genome sequencing has driven identification of novel genes and pathways implicated in WDL/DDL outside of the classic 12q13-15 amplicon. Due to their rarity; anatomical location and histologic subtype are infrequently mentioned when reporting the results of these studies. Reports can include non-adipogenic or extremity tumours, making it difficult to draw specific retroperitoneal conclusions. This narrative review aims to provide a summary of retroperitoneal liposarcoma genomics and the implications for therapeutic targeting.

Diagnostic importance of clinicopathologic features and p16, CD34, MDM2 expression in differential diagnosis of adipocytic tumors

OBJECTIVE

The aim of this study was to investigate the immunohistochemical stain profiling of adipocytic tumors.

METHODS

From our archive files between the years of 2012-2018, excised, formalin-fixed and paraffin-embedded adipocytic tumors were retrospectively screened and 61 subjects were selected. The gender, age, tumor location and tumor diameter were evaluated. The cases were investigated in terms of p16, CD34, MDM2 expression and clinicopathological information.

RESULTS

Of the 61 patients included in the study, we found that 2 had hibernoma, 4 had lipoblastoma, 14 had spindle cell lipoma (SCL), 10 had lipoma, 20 had atypical lipomatous tumor/well differentiated liposarcoma (ALT/WDL), and 11 had dedifferentiated liposarcoma (DDL). In terms of diameter, ALT/WDL and DDL were significantly different from the others (p=0.001, p=0.001, respectively). There was a significant difference between the groups according to the location (p=0.001). 35% (7/20) of ALT/WDLs were in the lower extremities (thighs) and 35% (7/20) were located in the retroperitoneal region. 70% of DDLs (7/11) were located in the retroperitoneum. When CD34 expression was evaluated among the groups, a significant difference was observed (p=0.001). CD34 was positive in 92.9% of SCL cases. p16 immunoreactivity was significantly different between the groups (p=0.001). p16 expression was observed in 50.5% of ALT / WDL cases and 79% of DDL cases.

CONCLUSION

p16 and CD34 expression are valuable in the differential diagnosis of lipomatous tumors when radiological and clinical considerations do not help to differential diagnosis of adipocytic tumors.

LEVEL OF EVIDENCE

Level IV, Therapeutic Study.

The transition of tissue inhibitor of metalloproteinases from -4 to -1 induces aggressive behavior and poor patient survival in dedifferentiated liposarcoma via YAP/TAZ activation

Liposarcoma (LS) is the most common soft-tissue sarcoma. Dedifferentiated liposarcoma (DDLS) shows more aggressive biological behavior than that of well-differentiated liposarcoma (WDLS), so advanced therapeutic agents based on molecular mechanism are urgently needed. Here we show that tissue inhibitors of metalloproteinases (TIMPs) from TIMP-1 to TIMP-4 are differently expressed and regulate yes-associated protein (YAP)/transcriptional co-activator with PDZ binding motif (TAZ) in LS. Database analysis showed high TIMP-1 expression in DDLS patients correlating with poor prognosis, but high TIMP-4 expression in WDLS patients with better prognosis. Stable TIMP-1 knockdown inactivated YAP/TAZ and inhibited proliferation, colony formation and migration in DDLS cells, which was rescued by a constitutive active YAP. However, stable overexpression of TIMP-1 showed the opposite in WDLS cells. Stable TIMP-4 knockdown activated YAP/TAZ and promoted proliferation and migration in WDLS cells, which was suppressed by YAP/TAZ inhibitor (verteporfin) or knockdown of YAP/TAZ. Recombinant TIMP-4 showed opposite results in DDLS cells. These results indicate that dedifferentiation in LS shifts the expression of TIMPs from type 4 to type 1, inducing more aggressive behavior and poor prognosis through YAP/TAZ activation, which can be prognostic markers and therapeutic targets for LS patients.

G-CSF-producing Undifferentiated Pleomorphic Sarcoma Adjacent to the Ascending Colon and in the Right Iliopsoas Muscle: A Case Report and Review of the Literature

Undifferentiated pleomorphic sarcoma (UPS) is a soft tissue sarcoma, occurring most commonly on the lower extremities. We herein report a rare case of primary UPS adjacent to the ascending colon and in the right iliopsoas muscle. Computed tomography of the abdomen revealed large masses, and the patient experienced a high-grade fever, leukocytosis, elevated serum C-reactive protein level, and hematopoietic activation on ¹⁸F-fluorodeoxyglucose-positron emission tomography. This inflammatory reaction was caused by granulocyte colony-stimulating factor secreted by tumor cells. Surgical resection was performed, and the inflammatory reaction disappeared immediately. The patient received adjuvant chemotherapy and survived one year after the operation without evidence of recurrence.

AZD1208, a Pan-Pim Kinase Inhibitor, Has Anti-Growth Effect on 93T449 Human Liposarcoma Cells via Control of the Expression and Phosphorylation of Pim-3, mTOR, 4EBP-1, S6, STAT-3 and AMPK

Overexpression of Pim kinases has an oncogenic/pro-survival role in many hematological and solid cancers. AZD1208 is a pan-Pim kinase inhibitor that has anti-cancer and anti-adipogenic actions. Here, we investigated the effects of AZD1208 on the growth of 93T449 cells, a differentiated human liposarcoma cell line. At 20 µM, AZD1208 was cytotoxic (cytostatic) but not apoptotic, reducing cell survival without DNA fragmentation, caspase activation or increasing cells in the sub G1 phase; known apoptotic parameters. Notably, AZD1208 reduced phosphorylation of signal transducer and activator of transcription-3 (STAT-3) in 93T449 cells. STAT-3 inhibition by AG490, a JAK2/STAT-3 inhibitor similarly reduced cell survival. AZD1208 down-regulated phosphorylation of mammalian target of rapamycin (mTOR) and ribosomal S6 while up-regulated eukaryotic initiation factor-2α (eIF-2α). In addition, AZD1208 induced a LKB-1-independent AMPK activation, which was crucial for its cytostatic effect, as knock-down of AMPK greatly blocked AZD1208s ability to reduce cell survival. AZD1208 had no effect on expression of two members of Pim kinase family (Pim-1 and Pim-3) but inhibited phosphorylation of 4EBP-1, a downstream effector of Pim kinases. Importantly, a central role for Pim-3 in the actions of AZD1208 was confirmed by knock-down, which not only reduced 93T449 cell survival but also led to the inhibition of 4EBP-1, mTOR, eIF-2α and STAT-3, along with the activation of AMPK. In summary, this is the first report demonstrating that AZD1208 inhibits growth of liposarcoma cells and that this activity is mediated through Pim-3 kinase, STAT-3, mTOR, S6 and AMPK expression and phosphorylation pathways.

Molecular mechanism and therapeutic implications of selinexor (KPT-330) in liposarcoma

Exportin-1 mediates nuclear export of multiple tumor suppressor and growth regulatory proteins. Aberrant expression of exportin-1 is noted in human malignancies, resulting in cytoplasmic mislocalization of its target proteins. We investigated the efficacy of selinexor against liposarcoma cells both in vitro and in vivo. Exportin-1 was highly expressed in liposarcoma samples and cell lines as determined by immunohistochemistry, western blot, and immunofluorescence assay. Knockdown of endogenous exportin-1 inhibited proliferation of liposarcoma cells. Selinexor also significantly decreased cell proliferation as well as induced cell cycle arrest and apoptosis of liposarcoma cells. The drug also significantly decreased tumor volumes and weights of liposarcoma xenografts. Importantly, selinexor inhibited insulin-like growth factor 1 (IGF1) activation of IGF-1R/AKT pathway through upregulation of insulin-like growth factor binding protein 5 (IGFBP5). Further, overexpression and knockdown experiments showed that IGFBP5 acts as a tumor suppressor and its expression was restored upon selinexor treatment of liposarcoma cells. Selinexor decreased aurora kinase A and B levels in these cells and inhibitors of these kinases suppressed the growth of the liposarcoma cells. Overall, our study showed that selinexor treatment restored tumor suppressive function of IGFBP5 and inhibited aurora kinase A and B in liposarcoma cells supporting the usefulness of selinexor as a potential therapeutic strategy for the treatment of this cancer.

Comprehensive adipocytic and neurogenic tissue microarray analysis of NY-ESO-1 expression - a promising immunotherapy target in malignant peripheral nerve sheath tumor and liposarcoma

BACKGROUND

Immunotherapy targeting cancer-testis antigen NY-ESO-1 shows promise for tumors with poor response to chemoradiation. Malignant peripheral nerve sheath tumors (MPNSTs) and liposarcomas (LPS) are chemoresistant and have few effective treatment options. Materials Methods: Using a comprehensive tissue microarray (TMA) of both benign and malignant tumors in primary, recurrent, and metastatic samples, we examined NY-ESO-1 expression in peripheral nerve sheath tumor (PNST) and adipocytic tumors. The PNST TMA included 42 MPNSTs (spontaneous n = 26, NF1-associated n = 16), 35 neurofibromas (spontaneous n = 22, NF-1 associated n = 13), 11 schwannomas, and 18 normal nerves. The LPS TMA included 48 well-differentiated/dedifferentiated (WD/DD) LPS, 13 myxoid/round cell LPS, 3 pleomorphic LPS, 8 lipomas, 1 myelolipoma, and 3 normal adipocytic tissue samples. Stained in triplicate, NY-ESO-1 intensity and density were scored.

RESULTS

NY-ESO-1 expression was exclusive to malignant tumors. 100% of myxoid/round cell LPS demonstrated NY-ESO-1 expression, while only 6% of WD/DD LPS showed protein expression, one of which was WD LPS. Of MPNST, 4/26 (15%) spontaneous and 2/16 (12%) NF1-associated MPNSTs demonstrated NY-ESO-1 expression. Strong NY-ESO-1 expression was observed in myxoid/round cell and dedifferentiated LPS, and MPNST in primary, neoadjuvant, and metastatic settings.

CONCLUSIONS

We found higher prevalence of NY-ESO-1 expression in MPNSTs than previously reported, highlighting a subset of MPNST patients who may benefit from immunotherapy. This study expands our understanding of NY-ESO-1 in WD/DD LPS and is the first demonstration of staining in a WD LPS and metastatic/recurrent myxoid/round cell LPS. These results suggest immunotherapy targeting NY-ESO-1 may benefit patients with aggressive tumors resistant to conventional therapy.

The emerging roles and therapeutic potential of cyclin-dependent kinase 11 (CDK11) in human cancer

Overexpression and/or hyperactivation of cyclin-dependent kinases (CDKs) are common features of most cancer types. CDKs have been shown to play important roles in tumor cell proliferation and growth by controlling cell cycle, transcription, and RNA splicing. CDK4/6 inhibitor palbociclib has been recently approved by the FDA for the treatment of breast cancer. CDK11 is a serine/threonine protein kinase in the CDK family and recent studies have shown that CDK11 also plays critical roles in cancer cell growth and proliferation. A variety of genetic and epigenetic events may cause universal overexpression of CDK11 in human cancers. Inhibition of CDK11 has been shown to lead to cancer cell death and apoptosis. Significant evidence has suggested that CDK11 may be a novel and promising therapeutic target for the treatment of cancers. This review will focus on the emerging roles of CDK11 in human cancers, and provide a proof-of-principle for continued efforts toward targeting CDK11 for effective cancer treatment.

The emerging roles and therapeutic potential of microRNAs (miRs) in liposarcoma

Liposarcoma (LPS) is a common subtype of soft tissue sarcoma and accounts for approximately 20% of adult sarcomas. Despite the progress in diagnosis and treatment of LPS, there is still a high mortality rate due to local recurrence or metastasis. The mechanisms underlying the development of recurrence and metastasis of LPS remain elusive. MicroRNAs (miRNAs or miRs) are non-coding RNAs that regulate target gene expression, influencing many cellular functions, including cell proliferation, apoptosis, differentiation, oncogenesis, and drug resistance in malignant cells. The dysregulation of miRs is involved in the initiation and progression of human cancers, including LPS. Functional studies have shown the potent pro- and anti-tumorigenic activity of specific miRs both in vitro and in vivo. miR signatures that are unique to specific types of LPS have been proposed. Several lines of evidence have shown that miRs can act either as oncogenes or tumor suppressor genes, as well as diagnostic and prognostic biomarkers for LPS. In addition, miRs may be a powerful therapeutic target in LPS, although obstacles such as delivery of miRs in vivo need to be overcome. In this review, we discuss the emerging roles of miRs in different histological subtypes of LPS.

Activation of the Akt-mTOR and MAPK pathways in dedifferentiated liposarcomas

The Akt/mTOR and MAPK pathways play important roles in modulating cellular function in response to extracellular signals, and they are known to be activated in certain kinds of sarcomas. Few investigations have examined these pathways in dedifferentiated liposarcoma (DDLS), in relation to clinicopathological features. Clinicopathological and immunohistochemical analyses were conducted using 99 DDLS specimens. An in vitro study was also conducted to examine the antitumor effects of an mTOR inhibitor and a MEK inhibitor on two DDLS cell lines. The clinicopathological analyses revealed that the AJCC staging was a significant prognostic factor for overall survival and that the tumor size, depth, and location were significant prognostic factors for event-free survival. Phosphorylated Akt (pAkt), pmTOR, pS6RP, p4E-BP1, pMEK, and pERK expressions were positive in 57.4, 52.4, 71.4, 57.1, 84.1, and 50.8 % of the dedifferentiated component of the 63 primary DDLSs. Positive staining for pmTOR was significantly more frequent in the dedifferentiated component than the well-differentiated component. A univariate prognostic analysis revealed that pmTOR expression was associated with poor prognosis in the tumors in the retroperitoneum/ventral body cavity. The mTOR and MEK inhibitors dose-dependently inhibited the cell proliferation of both DDLS cell lines and decreased the expression of downstream pS6RP and pERK, respectively. The combined use of the two inhibitors enhanced antiproliferative activity. In conclusion, the Akt/mTOR and MAPK pathways were activated in DDLS specimens, and the inhibition of these pathways decreased cell proliferation in DDLS cell lines. Our findings suggest that these pathways could be a therapeutic target for patients with DDLS.

The hepatocyte growth factor receptor as a potential therapeutic target for dedifferentiated liposarcoma

Dedifferentiated liposarcomas (DDLPS) are highly resistant to conventional chemo- and radiotherapies, with surgical resection remaining the classic treatment strategy; therefore, there is a pressing need for novel anti-DDLPS-targeted chemotherapeutics. Hepatocyte growth factor receptor (Met) expression is elevated in DDLPS, but the functional role of Met signaling in this disease is not known. We found that the in vitro stimulation of DDLPS cells with hepatocyte growth factor (HGF) elevated the degree of PI3K/AKT and MAPK pathway signaling, and that pro-tumorigenic phenotypes such as cell proliferation, invasion, and migration were significantly enhanced. Conversely, Met knockdown using shRNA-mediated interference decreased HGF-induced Met signaling, the invasive and migratory nature of DDLPS cells in vitro, and the tumorigenicity of DDLPS cells in vivo. These data strongly support the role for Met as a DDLPS therapeutic target. To that end, using EMD1214063, an ATP-competitive kinase inhibitor that targets Met more specifically than other kinases, inhibited Met-dependent signaling, reduced the oncogenicity of DDLPS cells in vitro, and significantly increased the survival of nude mice bearing subcutaneous DDLPS xenografts. These findings support further investigations of HGF-induced Met signaling inhibition in DDLPS, as a potential strategy to enhance clinical outcomes for this disease.

Increased H3K9me3 drives dedifferentiated phenotype via KLF6 repression in liposarcoma

Liposarcoma (LPS) can be divided into 4 different subtypes, of which well-differentiated LPS (WDLPS) and dedifferentiated LPS (DDLPS) are the most common. WDLPS is typically low grade, whereas DDLPS is high grade, aggressive, and carries a worse prognosis. WDLPS and DDLPS frequently co-occur in patients. However, it is not clear whether DDLPS arises independently from WDLPS, or whether epigenomic alterations underly the histopathological differences of these subtypes. Here, we profiled 9 epigenetic marks in tumor samples from 151 patients with LPS and showed elevated trimethylation of histone H3 at Lys9 (H3K9me3) levels in DDLPS tumors. Integrated ChIP-seq and gene expression analyses of patient-derived cell lines revealed that H3K9me3 mediates differential regulation of genes involved in cellular differentiation and migration. Among these, Kruppel-like factor 6 (KLF6) was reduced in DDLPS, with increased H3K9me3 at associated regulatory regions. Pharmacologic inhibition of H3K9me3 with chaetocin decreased DDLPS proliferation and increased expression of the adipogenesis-associated factors PPARγ, CEBPα, and CEBPβ, suggesting that increased H3K9me3 may mediate DDLPS-associated aggressiveness and dedifferentiation properties. KLF6 overexpression partially phenocopied chaetocin treatment in DDLPS cells and induced phenotypic changes that were consistent with adipocytic differentiation, suggesting that the effects of increased H3K9me3 may be mediated through KLF6. In conclusion, we provide evidence of an epigenetic basis for the transition between WDLPS and DDLPS.

Novel treatment targets in sarcoma: more than just the GIST

Sarcomas are rare tumors comprising a heterogeneous group of more than 50 histologic subtypes, the majority of which do not respond well to cytotoxic chemotherapy. This has fueled research into the distinct molecular mechanisms of tumorigenesis and disease progression for various sarcoma subtypes. Gastrointestinal stromal tumors and liposarcomas are presented as paradigms of molecular classification that have led to the rational development of novel therapeutic strategies for those tumors. Recent advances in understanding of growth signaling pathways, metabolic reprogramming, and immune therapy have identified new treatment targets for many sarcomas. These investigations will form the foundation for further improvements in our ability to care for patients with these tumors and may offer clinical insights into a wide range of other tumors.

A giant mesentery malignant solitary fibrous tumor recurring as dedifferentiated liposarcoma- a report of a very rare case and literature review

We report a case of a 59-year-old woman with a very rare giant mesentery malignant solitary fibrous tumor that recurred as dedifferentiated liposarcoma. The woman was admitted to the hospital because of low abdominal pain. Radiological and biopsy findings revealed a multi-lobulated giant malignant solitary fibrous tumor that had invaded the inferior vena cava, abdominal aorta, and superior mesentery vessels. The tumor was completely removed during the first cytoreductive surgery. Histopathologically, tumor had a heterogeneous cell population, composed of spindle cells with fibrous collagen proliferation. The spindle cells were not arranged in a specific pattern. Immunohistochemistry revealed that the tumor cells were positive for CD34, CD99, Bcl-2, and smooth muscle actin( SMA) and negative for CD117, epithelial membrane antigen (EMA), CAM5.7, S100, desmin, and caldesmon. The tumor recurred 9 months after surgery, and another cytoreductive surgery was then performed. The postoperative histopathological appearance of the invaded area indicated a well-differentiated liposarcoma. Formation of tumorous bone was also noted in the same area, in addition to atypical mesenchymal cells and multi-vacuolated lipoblasts in the area of the well-differentiated liposarcoma. Proliferated spindle cells arranged in a storiform pattern were found in the area adjacent to the tumor. Immunohistochemical analysis revealed that the tumors cells were positive for SMA, HHF-35, and caldesmon and negative for CD117, CD34, and S100. A diagnosis of dedifferentiated liposarcoma was made.

Soluble HMGB1 is a novel adipokine stimulating IL-6 secretion through RAGE receptor in SW872 preadipocyte cell line: contribution to chronic inflammation in fat tissue

Low-grade inflammation (LGI) is a central phenomenon in the genesis of obesity and insulin-resistance characterized by IL-6 in human serum. Whereas this LGI was initially thought to be mainly attributed to macrophage activation, it is now known that pre-adipocytes and adipocytes secrete several adipokines including IL-6 and participate to LGI and associated pathologies. In macrophages, HMGB1 is a nuclear yet secreted protein and acts as a cytokine to drive the production of inflammatory molecules through RAGE and TLR2/4. In this paper we tested the secretion of HMGB1 and the auto- and paracrine contribution to fat inflammation using the human preadipocyte cell line SW872 as a model. We showed that 1) human SW872 secreted actively HMGB1, 2) IL-6 production was positively linked to high levels of secreted HMGB1, 3) recombinant HMGB1 boosted IL-6 expression and this effect was mediated by the receptor RAGE and did not involve TLR2 or TLR4. These results suggest that HMGB1 is a major adipokine contributing to LGI implementation and maintenance, and can be considered as a target to develop news therapeutics in LGI associated pathologies such as obesity and type II diabetes.

Phase II trial of the CDK4 inhibitor PD0332991 in patients with advanced CDK4-amplified well-differentiated or dedifferentiated liposarcoma

PURPOSE

CDK4 is amplified in > 90% of well-differentiated (WDLS) and dedifferentiated liposarcomas (DDLS). The selective cyclin-dependent kinase 4 (CDK4)/CDK6 inhibitor PD0332991 inhibits growth and induces senescence in cell lines and xenografts. In a phase I trial of PD0332991, several patients with WDLS or DDLS experienced prolonged stable disease. We performed an open-label phase II study to determine the safety and efficacy of PD0332991 in patients with advanced WDLS/DDLS.

PATIENTS AND METHODS

Patients age ≥ 18 years experiencing disease progression while receiving systemic therapy before enrollment received PD0332991 200 mg orally once per day for 14 consecutive days in 21-day cycles. All were required to have CDK4 amplification by fluorescence in situ hybridization and retinoblastoma protein (RB) expression by immunohistochemistry (≥ 1+). The primary end point was progression-free survival (PFS) at 12 weeks, with 12-week PFS of ≥ 40% considered promising and ≤ 20% not promising. If ≥ nine of 28 patients were progression free at 12 weeks, PD0332991 would be considered active.

RESULTS

We screened 48 patients (44 of 48 had CDK4 amplification; 41 of 44 were RB positive). Of those, 30 were enrolled, and 29 were evaluable for the primary end point. Grade 3 to 4 events included anemia (17%), thrombocytopenia (30%), neutropenia (50%), and febrile neutropenia (3%). At 12 weeks, PFS was 66% (90% CI, 51% to 100%), significantly exceeding the primary end point. The median PFS was 18 weeks. There was one partial response.

CONCLUSION

Treatment with the CDK4 inhibitor PD0332991 was associated with a favorable progression-free rate in patients with CDK4-amplified and RB-expressing WDLS/DDLS who had progressive disease despite systemic therapy.

Primary pleomorphic liposarcoma of the orbit: a case report

To our knowledge, pleomorphic liposarcoma (PL) of the orbit has only been reported in the literature four times. This rarity makes it more difficult to diagnose and to treat in this clinical setting. A 62-year-old female presented with pruritus, edema, proptosis and diplopia 5 months OS. Imaging revealed an intraorbital mass displacing the globe, with infiltration into the sinus. The tumor was removed and the histological examination revealed a highly cellular tumor with heterogenous histology, with a few vacuolated cells and many malignant features. Immunohistochemistry allowed for the differential diagnosis, resulting in a diagnosis of PL of the orbit. The cells were immuno-positive for S-100 and negative for all other relevant markers. According to the literature, prognosis for this neoplasm is quite poor, and exenteration represents the best treatment option. The patient refused exenteration and radiation therapy, however, at 2 year follow-up, she remained recurrence-free.

Distinct cytoplasmic and nuclear functions of the stress induced protein DDIT3/CHOP/GADD153

DDIT3, also known as GADD153 or CHOP, encodes a basic leucine zipper transcription factor of the dimer forming C/EBP family. DDIT3 is known as a key regulator of cellular stress response, but its target genes and functions are not well characterized. Here, we applied a genome wide microarray based expression analysis to identify DDIT3 target genes and functions. By analyzing cells carrying tamoxifen inducible DDIT3 expression constructs we show distinct gene expression profiles for cells with cytoplasmic and nuclear localized DDIT3. Of 175 target genes identified only 3 were regulated by DDIT3 in both cellular localizations. More than two thirds of the genes were downregulated, supporting a role for DDIT3 as a dominant negative factor that could act by either cytoplasmic or nuclear sequestration of dimer forming transcription factor partners. Functional annotation of target genes showed cell migration, proliferation and apoptosis/survival as the most affected categories. Cytoplasmic DDIT3 affected more migration associated genes, while nuclear DDIT3 regulated more cell cycle controlling genes. Cell culture experiments confirmed that cytoplasmic DDIT3 inhibited migration, while nuclear DDIT3 caused a G1 cell cycle arrest. Promoters of target genes showed no common sequence motifs, reflecting that DDIT3 forms heterodimers with several alternative transcription factors that bind to different motifs. We conclude that expression of cytoplasmic DDIT3 regulated 94 genes. Nuclear translocation of DDIT3 regulated 81 additional genes linked to functions already affected by cytoplasmic DDIT3. Characterization of DDIT3 regulated functions helps understanding its role in stress response and involvement in cancer and degenerative disorders.

Aberrant calreticulin expression is involved in the dedifferentiation of dedifferentiated liposarcoma

Liposarcomas are a representative group of soft tissue sarcomas with variably hampered adipogenesis, which is most exemplified by its dedifferentiated subtype. However, the factor(s) responsible for inhibiting adipocyte differentiation remains unknown. A recent gene expression profiling study identified several unique genes that were highly expressed in dedifferentiated liposarcoma, and the gene encoding calreticulin (CALR), a major Ca(2+)-buffering protein that can inhibit adipocyte differentiation, was found to be overexpressed. Thus, we investigated the expression of calreticulin in 45 cases of liposarcomas, including 15 dedifferentiated tumors, at both the protein and mRNA levels. Immunohistochemically, calreticulin was consistently expressed in the dedifferentiated areas of dedifferentiated liposarcomas and commonly observed in atypical stromal cells and/or lipoblasts in the well-differentiated areas (87%), whereas large vacuolated adipocytic cells in either the tumors or normal fat were essentially negative. These results were further supported by the findings of Western blot and quantitative RT-PCR analyses. Although abnormalities in 19p13.1-13.2 where CALR is localized were uncommon in the dedifferentiated liposarcomas examined by fluorescence in situ hybridization, expression of miR-1257, a putative microRNA that targets calreticulin, was suppressed in the dedifferentiated subtype. The down-regulation of calreticulin by small-interfering RNA could induce adipogenesis in dedifferentiated liposarcoma cells and reduce cell proliferation. Our results therefore suggest that aberrantly expressed calreticulin in dedifferentiated liposarcoma is involved in its dedifferenitation and/or tumor progression.

Restoration of C/EBPα in dedifferentiated liposarcoma induces G2/M cell cycle arrest and apoptosis

Well-differentiated liposarcoma (WDLS) and dedifferentiated liposarcoma (DDLS) represent the most common biological group of liposarcoma, and there is a pressing need to develop targeted therapies for patients with advanced disease. To identify potential therapeutic targets, we sought to identify differences in the adipogenic pathways between DDLS, WDLS, and normal adipose tissue. In a microarray analysis of DDLS (n = 84), WDLS (n = 79), and normal fat (n = 23), C/EBPα, a transcription factor involved in cell cycle regulation and differentiation, was underexpressed in DDLS when compared to both WDLS and normal fat (15.2- and 27.8-fold, respectively). In normal adipose-derived stem cells, C/EBPα expression was strongly induced when cells were cultured in differentiation media, but in three DDLS cell lines, this induction was nearly absent. We restored C/EBPα expression in one of the cell lines (DDLS8817) by transfection of an inducible C/EBPα expression vector. Inducing C/EBPα expression reduced proliferation and caused cells to accumulate in G2/M. Under differentiation conditions, the cell proliferation was reduced further, and 66% of the DDLS cells containing the inducible C/EBPα expression vector underwent apoptosis as demonstrated by annexin V staining. These cells in differentiation conditions expressed early adipocyte-specific mRNAs such as LPL and FABP4, but they failed to accumulate intracellular lipid droplets, a characteristic of mature adipocytes. These results demonstrate that loss of C/EBPα is an important factor in suppressing apoptosis and maintaining the dedifferentiated state in DDLS. Restoring C/EBPα may be a useful therapeutic approach for DDLS.

Establishing efficient xenograft models with intrinsic vascularisation for growing primary human low-grade sarcomas

BACKGROUND

There are no xenograft models of low-grade soft tissue sarcoma. Transplant survival remains an obstacle in sarcoma xenograft models and is attributed to post-transplantation hypoxia. Models with an intrinsic tissue - engineered vascular supply may overcome this obstacle. The aim of this study was to establish a novel xenograft model of primary human low grade soft tissue sarcoma.

MATERIALS AND METHODS

Primary low-grade liposarcoma fragments were transplanted into a silicon chamber, placed around the superficial epigastric vessels in athymic nude mice. Xenograft samples were assessed histologically (light/electron microscopy and immunohistochemistry for S100).

RESULTS

All xenotransplants of low grade primary soft tissue liposarcoma (n=4) engrafted, led to the development of solid tumours in mice. Histological and immunohistochemical staining confirmed the xenografts as being well-differentiated liposarcomas identical to the original tumor tissue.

CONCLUSION

Successful transplantation of human low-grade liposarcoma tissue in mice was established for the first time using a model with an intrinsic vascular supply.

High fat diet induces formation of spontaneous liposarcoma in mouse adipose tissue with overexpression of interleukin 22

Interleukin 22 (IL-22) is a T-cell secreted cytokine that modulates inflammatory response in nonhematopoietic tissues such as epithelium and liver. The function of IL-22 in adipose tissue is currently unknown. We generated a transgenic mouse model with overexpression of IL-22 specifically in adipose tissue. The IL-22 transgenic mice had no apparent changes in obesity and insulin resistance after feeding with high fat diet (HFD). Unexpectedly, all the IL-22 transgenic mice fed with HFD for four months developed spontaneous tumors in epididymal adipose tissue. Histological analysis indicated that the tumors were well-differentiated liposarcomas with infiltration of inflammatory cells. IL-22 overexpression promotes production of inflammatory cytokines such as IL-1β and IL-10 and stimulates ERK phosphorylation in adipose tissue. Furthermore, IL-22 treatment in differentiated 3T3-L1 adipocytes could induce IL-1β and IL-10 expression, together with stimulation of ERK phosphorylation. Taken together, our study not only established a novel mouse model with spontaneous liposarcoma, but also revealed that IL-22 overexpression may collaborate with diet-induced obesity to impact on tumor development in mouse.

Arginine metabolism in soft tissue sarcoma

BACKGROUND

L-Arginine (L-Arg) is a conditionally essential amino acid for humans, which is the substrate for both arginase (ARG) and the inducible form of nitric oxide synthase (iNOS) enzymes. Whether L-Arg metabolism has detrimental or beneficial influence on the tumor growth depends on local up regulation of the NOS or ARG pathways at the tumor site.

OBJECTIVE

To evaluate the expression profile of ARG and iNOS in various histological subtypes of soft tissue sarcomas (STSs).

METHODS

A series of 81 adult STSs were tested for ARG1, ARG2 and iNOS expression by immunohistochemical analysis.

RESULTS

ARG1, ARG2 and iNOS expression was found in tumor cells of all cases of STSs except dermatofibrosarcoma protuberans (DFSP) in a cytoplasmic pattern. However, there was no significant correlation found between ARG, iNOS expression and histopathological parameters. Conversely, the majority of DFSP were devoid of ARG and iNOS expression, while only two cases showed focal and weak expression.

CONCLUSIONS

Overexpression of L-Arg-metabolizing enzymes ARG and iNOS in tumor cells of all of the STS cases except DFSP may have a role in mediating the biological processes which characterize STSs. New knowledge of the regulation of arginine metabolism in tumor tissues is key to designing sound therapeutic means to effectively prevent tumorigenesis. Further studies are needed to clarify the absence of ARG and iNOS staining in DFSP.

G protein-coupled receptor kinase 2 plays a relevant role in insulin resistance and obesity

OBJECTIVE

Insulin resistance is associated with the pathogenesis of metabolic disorders as type 2 diabetes and obesity. Given the emerging role of signal transduction in these syndromes, we set out to explore the possible role that G protein-coupled receptor kinase 2 (GRK2), first identified as a G protein-coupled receptor regulator, could have as a modulator of insulin responses.

RESEARCH DESIGN AND METHODS

We analyzed the influence of GRK2 levels in insulin signaling in myoblasts and adipocytes with experimentally increased or silenced levels of GRK2, as well as in GRK2 hemizygous animals expressing 50% lower levels of this kinase in three different models of insulin resistance: tumor necrosis factor-α (TNF-α) infusion, aging, and high-fat diet (HFD). Glucose transport, whole-body glucose and insulin tolerance, the activation status of insulin pathway components, and the circulating levels of important mediators were measured. The development of obesity and adipocyte size with age and HFD was analyzed.

RESULTS

Altering GRK2 levels markedly modifies insulin-mediated signaling in cultured adipocytes and myocytes. GRK2 levels are increased by ∼2-fold in muscle and adipose tissue in the animal models tested, as well as in lymphocytes from metabolic syndrome patients. In contrast, hemizygous GRK2 mice show enhanced insulin sensitivity and do not develop insulin resistance by TNF-α, aging, or HFD. Furthermore, reduced GRK2 levels induce a lean phenotype and decrease age-related adiposity.

CONCLUSIONS

Overall, our data identify GRK2 as an important negative regulator of insulin effects, key to the etiopathogenesis of insulin resistance and obesity, which uncovers this protein as a potential therapeutic target in the treatment of these disorders.

Pleural liposarcoma mimicking carcinoma in pleural effusion cytology: a case report

BACKGROUND

Primary pleural liposarcoma is extremely rare, and its most common subtype is the myxoid subtype. To the best of our knowledge, the number of cases reported up to now is <20. It is primarily a disease ofindividuals 50 years of age and it is more common in men. It has no specific symptoms except for cough and chest pain.

CASE

A 56-year-old female presented complaining of chest pain and dyspnea for 4 months. An increase in homogeneous density on the left hemithorax, from the apex to basal area, with blurring of the borders of the heart and the diaphragm, was revealed by lung radiography. Thoracic computed tomography revealed a diffuse pleural effusion causing compressive atelectasis at the base of the left hemithorax. Cytologic examination of the pleural fluid demonstrated tumoral cells forming papillary structures with complex branching and fine fibrovascular core. The tumor cells were relatively uniform and had vacuolar cytoplasm with hyperchromatic nuclei. Upon finding CA-125 positive in the immunocytochemical examination, the case was reported as "consistent with malignancy, possibility of ovarian origin, cannot be excluded". As the gynecologic examination was normal, exploratory thoracotomy was performed to take a biopsy. The case was diagnosed as liposarcoma (myxoid type) by histopathologic examination.

CONCLUSION

Cytologic diagnosis of pleural liposarcoma is difficult due to its rarity and resemblance to malignant mesothelioma. Cytologic properties of liposarcoma in pleural fluid should be well known and considered in the differential diagnosis.

Chromophobe renal cell carcinoma with liposarcomatous dedifferentiation - report of a unique case

Sarcomatous transformation of chromophobe renal cell carcinoma (CRCC) is a well recognized phenomenon. Of the published cases with sarcomatous transformation of CRCC, none have shown liposarcomatous differentiation. Out of a cohort of 250 cases of CRCC, 19 (7.6%) showed sarcomatous differentiation. In one case (female, age 46 years), the sarcomatous component of the tumor displayed histological features of a pleomorphic liposar-coma. Light microscopic examination revealed a biphasic pattern with a chromophobe renal cell carcinoma(CRCC) and a high-grade sarcomatous component containing large pleomorphic lipoblasts. In several areas both components were intermingled. The conventional CRCC component showed classic histological features with calcifications, medium-sized polygonal cells arranged in solid-alveolar structures with raisinoid nuclei, pale-eosinophilic flocculent cytoplasm with perinuclear haloes. In addition, a microcystic-adenomatous component had luminal spaces filled with erythrocytes. The CRCC was positive with Hale's colloidal iron-stain whereas the sarcomatous component was negative. The CRCC component was diffusely positive for cytokeratin 7, parvalbumin and racemase but negative for cy-tokeratin 20, vimentin, CD10, carboanhydrase IX and S100-protein. The pleomorphic liposarcomatous component displayed immunereactivity for CD10, vimentin, racemase and focally for carboanhydrase IX. The proliferative activity (Mib-1/Ki-67) was 5% in the CRCC and 30% in the pleomorphic liposarcomatous component. No immunereactivity for MDM2 or CDK4 was detected.This is the first reported case of a sarcomatoid CRCC where the sarcomatous component displayed features of a pleomorphic liposarcoma. The patient died from widespread metastatic disease 12 months after nephrectomy.

[Molecular diagnosis of liposarcomas: identification of the chimeric genes FUS/CHOP and EWS/CHOP]

This paper presents the results of an analysis the chimeric genes FUS/CHOP and EWS/CHOP in patients diagnosed as having liposarcoma in order to make a differential diagnosis in both soft tissue tumors and various variants of liposarcoma. Liposarcomas were found in 5 of 7 cases of primary tumors: 4 chimeric transcripts of the FUS/CHOP type (5-2), a variant of alternative splicing of the FUS/CHOP type (5-2) with depletion in 14 p.n. anda rare variant of the EWS/CHOP type (7-2). Fluorescence in situ hybridization (FISH) confirmed translocations in the tumor samples with the chimeric genes being detected. Reverse transcription-polymerase chain reaction and FISH revealed no chimeric genes specific to myxoid sarcoma in a group of patients with other variants of liposarcoma. Thus, the findings support the strict specificity of the chimeric genes FUS/CHOP and EWS/CHOP for myxoid liposarcoma and the expression of these genes in most tumors of this type.

Identification of preferential protein targets for carbonylation in human mature adipocytes treated with native or glycated albumin

Oxidative modifications in proteins can participate in the regulation of cellular functions and are frequently observed in numerous states of diseases. Albumin can undergo increased glycation during diabetes. An accumulation of oxidatively modified proteins in human mature adipocytes incubated with glycated albumin has previously been described. This study herein reports the identification of specifically carbonylated targets following separation of the cell proteins by 2D gels, Western blotting and mass spectrometry analyses. It identified eight oxidatively modified proteins, two of which (ACTB and Annexin A2) appeared as significantly more carbonylated in adipocytes treated with glycated albumin than with native albumin. Intracellular stress, evaluated in SW872 cell line, showed an impairment in the protective antioxidant action exerted by native BSA after the glycation of the protein. Decreased proteasome peptidase activities were found in glycated BSA-treated mature adipocytes. The data suggest an association of oxidative damage with the progression of diabetes disorders at the adipocytes level.

[Correlation of telomere length and the expression of its regulating proteins in mesenchymal sarcomas]

OBJECTIVE

To explore the significance in the change of telomere length in mesenchymal sarcomas, through analyzing telomere length and expression of its associated proteins, including TRF1, POT1, hTERT, P53 and c-myc.

METHODS

The telomere length in 20 cases of osteosarcomas, 25 of chondrosarcomas, 19 of rhabdomyosarcomas, 26 of liposarcomas was measured by telomere fluorescence in situ hybridization (Telo-FISH), and the expression of TRF1, POT1, hTERT, p53 or c-myc was analyzed by immunohistochemistry, respectively.

RESULTS

The telomere length in osteosarcomas was significantly shorter than that of either chondrosarcomas or liposarcomas (P<0.05). Similarly, the telomere length of rhabdomyosarcoma was shorter than that of chondrosarcoma (P<0.05). Meanwhile, telomere shortening was positively correlated with down expression of telomere binding proteins TRF1 and POT1 (P<0.05), but trends were detected more frequently in positive expression of hTERT (P<0.05) and in nuclear accumulation of P53 or expression of c-myc. With advancing in histological grading, telomere length was shortened markedly in chondrosarcomas, especially in liposarcomas (P<0.05).

CONCLUSION

The shortening of telomere could prevail in mesenchymal sarcoma and reflect the malignant potential. Telomere attrition usually correlated with down expression of POT1, TRF1 and with increased levels of hTERT, P53 and c-myc.

FUS-DDIT3 prevents the development of adipocytic precursors in liposarcoma by repressing PPARgamma and C/EBPalpha and activating eIF4E

Background

FUS-DDIT3 is a chimeric protein generated by the most common chromosomal translocation t(12;16)(q13;p11) linked to liposarcomas, which are characterized by the accumulation of early adipocytic precursors. Current studies indicate that FUS-DDIT3- liposarcoma develops from uncommitted progenitors. However, the precise mechanism whereby FUS-DDIT3 contributes to the differentiation arrest remains to be elucidated.

Methodology/Principal Findings

Here we have characterized the adipocyte regulatory protein network in liposarcomas of FUS-DITT3 transgenic mice and showed that PPARγ2 and C/EBPα expression was altered. Consistent with in vivo data, FUS-DDIT3 MEFs and human liposarcoma cell lines showed a similar downregulation of both PPARγ2 and C/EBPα expression. Complementation studies with PPARγ but not C/EBPα rescued the differentiation block in committed adipocytic precursors expressing FUS-DDIT3. Our results further show that FUS-DDIT3 interferes with the control of initiation of translation by upregulation of the eukaryotic translation initiation factors eIF2 and eIF4E both in FUS-DDIT3 mice and human liposarcomas cell lines, explaining the shift towards the truncated p30 isoform of C/EBPα in liposarcomas. Suppression of the FUS-DDIT3 transgene did rescue this adipocyte differentiation block. Moreover, eIF4E was also strongly upregulated in normal adipose tissue of FUS-DDIT3 transgenic mice, suggesting that overexpression of eIF4E may be a primary event in the initiation of liposarcomas. Reporter assays showed FUS-DDIT3 is involved in the upregulation of eIF4E in liposarcomas and that both domains of the fusion protein are required for affecting eIF4E expression.

Conclusions/Significance

Taken together, this study provides evidence of the molecular mechanisms involve in the disruption of normal adipocyte differentiation program in liposarcoma harbouring the chimeric gene FUS-DDIT3.

Prognostic factors and expression of MDM2 in patients with primary extremity liposarcoma

OBJECTIVE

The objective of this study was to investigate MDM2 (murine double minute 2) protein expression and evaluate its relationship with some anatomical and pathological aspects, aiming also to identify prognostic factors concerning local recurrence-free survival, metastasis-free survival and overall survival in patients with primary liposarcomas of the extremities.

MATERIALS AND METHODS

Of 50 patients with primary liposarcomas of the extremities admitted to a Reference Service, between 1968 and 2004, 25 were enrolled in the study, following eligibility and exclusion criteria.

RESULTS

The adverse factors that influenced the risk for local recurrence in the univariant analysis included male sex (P = 0.023), pleomorphic histological subtype (P = 0.027), and high histological grade (P = 0.007). Concerning metastasis-free survival, age less than 50 years (P = 0.040), male sex (P = 0.040), pleomorphic subtype (P < 0.001), and high histological grade (P = 0.003) had a worse prognosis. Adverse factors for overall survival were age under 50 years (P = 0.040), male sex (P = 0.040), pleomorphic subtype (P < 0.001), and high histological grade (P = 0.003).

CONCLUSIONS

There was no correlation between immunohistochemically observed MDM2 protein expressions and the anatomical and pathological variables studied. The immunohistochemical expression of MDM2 protein was not considered to have a prognostic value for any of the surviving patients in this study (local recurrence-free survival, metastasis-free survival, or overall survival). The immunoexpression of MDM2 protein was a frequent event in the different subtypes of liposarcomas.

Detection of MDM2-CDK4 Amplification by Fluorescence In Situ Hybridization in 200 Paraffin-embedded Tumor Samples: Utility in Diagnosing Adipocytic Lesions and Comparison With Immunohistochemistry and Real-time PCR

Atypical lipomatous tumor/well-differentiated liposarcomas and dedifferentiated liposarcomas are characterized by the amplification of MDM2 and CDK4 genes. To evaluate the accuracy of fluorescence in situ hybridization (FISH) analysis in the differential diagnosis of adipose tissue tumors, we investigated MDM2-CDK4 status by FISH, real-time polymerase chain reaction (PCR) [quantitative PCR (Q-PCR)] and immunohistochemistry (IHC) in a series of 200 adipose tumors. First, we evaluated MDM2-CDK4 amplification and expression in a series of 94 well-defined adipose tissue tumors. Results showed that FISH was interpretable in 45 of 50 cases (90%), and was more specific and sensitive than Q-PCR and IHC. We then used the same techniques as complementary diagnostic tools in a series of 106 adipose and soft tissue tumors of unclear diagnosis to distinguish between (i) lipomas and atypical lipomatous tumor/well-differentiated liposarcomas, (ii) malignant undifferentiated tumors and dedifferentiated liposarcomas, and (iii) a variety of benign tumors and liposarcomas. Our results indicate that although helpful, IHC alone is often insufficient to solve diagnostic problems. FISH and Q-PCR methods gave concordant results and were equally informative in most cases. However, the proportion of noninterpretable cases was slightly higher with FISH than with Q-PCR. When tumor cells represented a minor component of the tumor tissue, such as with inflammatory tumors, FISH was more powerful than Q-PCR by allowing visualization of individual cells. In conclusion, we recommend that the evaluation of MDM2-CDK4 amplification using FISH or Q-PCR be used to supplement IHC analysis when diagnosis of adipose tissue tumors is not possible based on clinical and histologic information alone.

Gene expression profiling of liposarcoma identifies distinct biological types/subtypes and potential therapeutic targets in well-differentiated and dedifferentiated liposarcoma

Classification of liposarcoma into three biological types encompassing five subtypes, (a) well-differentiated/dedifferentiated, (b) myxoid/round cell, and (c) pleomorphic, based on morphologic features and cytogenetic aberrations, is widely accepted. However, diagnostic discordance remains even among expert sarcoma pathologists. We sought to develop a more systematic approach to liposarcoma classification based on gene expression analysis and to identify subtype-specific differentially expressed genes that may be involved in liposarcoma genesis/progression and serve as potential therapeutic targets. A classifier based on gene expression profiling was able to distinguish between liposarcoma subtypes, lipoma, and normal fat samples. A 142-gene predictor of tissue class was derived to automatically determine the class of an independent validation set of lipomatous samples and shows the feasibility of liposarcoma classification based entirely on gene expression monitoring. Differentially expressed genes for each liposarcoma subtype compared with normal fat were used to identify histology-specific candidate genes with an in-depth analysis of signaling pathways important to liposarcoma pathogenesis and progression in the well-differentiated/dedifferentiated subset. The activation of cell cycle and checkpoint pathways in well-differentiated/dedifferentiated liposarcoma provides several possible novel therapeutic strategies with MDM2 serving as a particularly promising target. We show that Nutlin-3a, an antagonist of MDM2, preferentially induces apoptosis and growth arrest in dedifferentiated liposarcoma cells compared with normal adipocytes. These results support the development of a clinical trial with MDM2 antagonists for liposarcoma subtypes which overexpress MDM2 and show the promise of using this expression dataset for new drug discovery in liposarcoma.

Epithelioid Variant of Pleomorphic Liposarcoma in a Heifer

A case of epithelioid variant of liposarcoma in a 31-month-old Japanese Black heifer is described. The tumour mass, which formed in the subcutis of the left cheek, was excised surgically, but this was followed by recurrence and metastasis to lymph nodes. The primary tumour was composed of sheets of lipid-laden cells, and anaplastic larger cells with eosinophilic or amphophilic cytoplasm were occasionally seen. In addition to vimentin and S-100 protein expression in the majority of tumour cells, squamous and non-squamous cytokeratins (CKs) were present, mainly in the larger cells, which predominated in the metastatic lesions. The expression of CKs was considered to be evidence of epithelioid differentiation.

Potential for treatment of liposarcomas with the MDM2 antagonist Nutlin-3A

The MDM2-antagonist Nutlin 3A can efficiently induce apoptosis in osteosarcoma cell lines with amplified MDM2. However, Nutlin-based therapy could be even more important in more common sarcoma types where this aberration is frequent. The well- and de-differentiated liposarcomas have complex marker chromosomes, consistently including multiple copies of the MDM2 locus. Since amplification seems to be a primary aberration in these tumors, whereas amplification in osteosarcoma generally is a progression marker, the underlying biological mechanisms may be different. We have therefore investigated the molecular response to Nutlin treatment in several liposarcoma cell lines with such markers, as well as a panel of other sarcoma cell lines. We report that Nutlin efficiently stabilized p53 and induced downstream p53 dependent transcription and apoptosis in liposarcoma cells with amplified MDM2 in vitro. Some effect of Nutlin was also observed on cell lines without amplified MDM2 but with wt TP53, but no apoptosis was induced. The MDM4 protein, reported to interfere with the reactivation of p53, was undetectable in cells with amplified MDM2. Thus, Nutlin represents a promising new therapeutic principle for the treatment of an increasing group of sarcomas.

HMGA2 regulates transcription of the Imp2 gene via an intronic regulatory element in cooperation with nuclear factor-kappaB

IMP2 (insulin-like growth factor-II mRNA binding protein 2) is an oncofetal protein that is aberrantly expressed in several types of cancer. We recently identified the Imp2 gene as a target gene of the architectural transcription factor HMGA2 (high mobility group A2) and its tumor-specific truncated form HMGA2Tr. In this study, we investigated the mechanism via which HMGA2 regulates Imp2 gene expression. We show that HMGA2 and HMGA2Tr directly regulate transcription of the Imp2 gene by binding to an AT-rich regulatory region located in the first intron. In reporter experiments, we show that this AT-rich regulatory region mimics the response of the endogenous Imp2 gene to HMGA2 and HMGA2Tr. Furthermore, we show that a consensus nuclear factor-kappaB (NF-kappaB) binding site located immediately adjacent to the AT-rich regulatory region binds NF-kappaB and that NF-kappaB and HMGA2 cooperate to regulate Imp2 gene expression. Finally, we provide evidence that there is a strong and statistically significant correlation between HMGA2 and IMP2 gene expression in human liposarcomas.

JUN oncogene amplification and overexpression block adipocytic differentiation in highly aggressive sarcomas

The human oncogene JUN encodes a component of the AP-1 complex and is consequently involved in a wide range of pivotal cellular processes, including cell proliferation, transformation, and apoptosis. Nevertheless, despite extensive analyses of its functions, it has never been directly involved in a human cancer. We demonstrate here that it is highly amplified and overexpressed in undifferentiated and aggressive human sarcomas, which are blocked at an early step of adipocyte differentiation. We confirm by cellular and xenograft mouse models recapitulating these sarcoma genetics that the failure to differentiate is dependent upon JUN amplification/overexpression.

Analysis of germline and tumor mutations of p53 gene in familial occurrence of soft tissue sarcomas

BACKGROUND

Familial soft tissue sarcomas are extremely rare. There is little information available on the clinical features and molecular findings of the hereditary occurrence of mesenchymal tumor.

PATIENTS AND METHODS

A woman and her younger brother had malignant fibrous histiocytoma (pleomorphic type) and liposarcoma (pleomorphic type) in the lower limbs, respectively. Analysis of p53 mutations in exons 5-9 of the tumor and in germ-line was done.

RESULTS

A guanine to adenine substitution occurred in CGC, codon 175 of exon 5 in p53 gene, to CAC in the tumor sample of Case 1. Likewise, a thymine to cytosine substitution occurred in TTT, codon 270 of exon 8 in p53 gene, to TCT in tumor sample of Case 2. Germline mutations were not seen in the either patients.

CONCLUSIONS

Different missense mutations of p53 were detected in each tumor, however no germline mutations of p53 were found. The alteration of codon 175 in Case 1 is relatively common mutation. On the contrary, the mutation in codon 270 in Case 2 was extremely rare in cancers. Further molecular investigation is needed to understand the mechanism in familial occurrence of sarcomas.