Aberrant calreticulin expression is involved in the dedifferentiation of dedifferentiated liposarcoma

CD47 as a potent target in cancer immunotherapy: A review

Cancer is the second-highest cause of death worldwide. Accordingly, finding new cancer treatments is of great interest to researchers. The current platforms to fight cancer such as chemotherapy, radiotherapy, and surgery are limited in efficacy, especially in the metastatic setting. In this war against cancer, the immune system is a powerful ally, but tumor cells often outsmart it through alternative pathways. Cluster of differentiation 47 (CD47), a protein that normally prevents healthy cells from being attacked by immune cells, is often overexpressed on cancer cells. This makes CD47 a prime target for immunotherapy. Blocking of CD47 has the potential to unleash the immune system's cell populations-such as myeloid cells, macrophages, and T cells-to allow the immune system to discover and destroy cancer cells more successfully. In this review, we aimed to provide the latest information and findings about the roles of CD47 in the regulation of various cellular pathways and, thus, the importance of CD47 as a potential target in cancer therapy.

Combinatorial macrophage induced innate immunotherapy against Ewing sarcoma: Turning "Two Keys" simultaneously

BACKGROUND

Macrophages play important roles in phagocytosing tumor cells. However, tumors escape macrophage phagocytosis in part through the expression of anti-phagocytic signals, most commonly CD47. In Ewing sarcoma (ES), we found that tumor cells utilize dual mechanisms to evade macrophage clearance by simultaneously over-expressing CD47 and down-regulating cell surface calreticulin (csCRT), the pro-phagocytic signal. Here, we investigate the combination of a CD47 blockade (magrolimab, MAG) to inhibit the anti-phagocytic signal and a chemotherapy regimen (doxorubicin, DOX) to enhance the pro-phagocytic signal to induce macrophage phagocytosis of ES cells in vitro and inhibit tumor growth and metastasis in vivo.

METHODS

Macrophages were derived from human peripheral blood monocytes by granulocyte-macrophage colony-stimulating factor (GM-CSF) and macrophage colony-stimulating factor (M-CSF). Flow cytometry- and microscopy-based in-vitro phagocytosis assays were performed to evaluate macrophage phagocytosis of ES cells. Annexin-V assay was performed to evaluate apoptosis. CD47 was knocked out by CRISPR/Cas9 approach. ES cell-based and patient-derived-xenograft (PDX)-based mouse models were utilized to assess the effects of MAG and/or DOX on ES tumor development and animal survival. RNA-Seq combined with CIBERSORTx analysis was utilized to identify changes in tumor cell transcriptome and tumor infiltrating immune cell profiling in MAG and/or DOX treated xenograft tumors.

RESULTS

We found that MAG significantly increased macrophage phagocytosis of ES cells in vitro (p < 0.01) and had significant effect on reducing tumor burden (p < 0.01) and increasing survival in NSG mouse model (p < 0.001). The csCRT level on ES cells was significantly enhanced by DOX in a dose- and time-dependent manner (p < 0.01). Importantly, DOX combined with MAG significantly enhanced macrophage phagocytosis of ES cells in vitro (p < 0.01) and significantly decreased tumor burden (p < 0.01) and lung metastasis (p < 0.0001) and extended animal survival in vivo in two different mouse models of ES (p < 0.0001). Furthermore, we identified CD38, CD209, CD163 and CD206 as potential markers for ES-phagocytic macrophages. Moreover, we found increased M2 macrophage infiltration and decreased expression of Cd209 in the tumor microenvironment of MAG and DOX combinatorial therapy treated tumors.

CONCLUSIONS

By turning "two keys" simultaneously to reactivate macrophage phagocytic activity, our data demonstrated an effective and highly translatable alternative therapeutic approach utilizing innate (tumor associated macrophages) immunotherapy against high-risk metastatic ES.

Decoding contextual crosstalk: revealing distinct interactions between non-coding RNAs and unfolded protein response in breast cancer

Breast cancer is significantly influenced by endoplasmic reticulum (ER) stress, impacting both its initiation and progression. When cells experience an accumulation of misfolded or unfolded proteins, they activate the unfolded protein response (UPR) to restore cellular balance. In breast cancer, the UPR is frequently triggered due to challenging conditions within tumors. The UPR has a dual impact on breast cancer. On one hand, it can contribute to tumor growth by enhancing cell survival and resistance to programmed cell death in unfavorable environments. On the other hand, prolonged and severe ER stress can trigger cell death mechanisms, limiting tumor progression. Furthermore, ER stress has been linked to the regulation of non-coding RNAs (ncRNAs) in breast cancer cells. These ncRNAs, including microRNAs (miRNAs) and long non-coding RNAs (lncRNAs), play essential roles in cancer development by influencing gene expression and cellular processes. An improved understanding of how ER stress and ncRNAs interact in breast cancer can potentially lead to new treatment approaches. Modifying specific ncRNAs involved in the ER stress response might interfere with cancer cell survival and induce cell death. Additionally, focusing on UPR-associated proteins that interact with ncRNAs could offer novel therapeutic possibilities. Therefore, this review provides a concise overview of the interconnection between ER stress and ncRNAs in breast cancer, elucidating the nuanced effects of the UPR on cell fate and emphasizing the regulatory roles of ncRNAs in breast cancer progression.

circSMARCA5 Is an Upstream Regulator of the Expression of miR-126-3p, miR-515-5p, and Their mRNA Targets, Insulin-like Growth Factor Binding Protein 2 (IGFBP2) and NRAS Proto-Oncogene, GTPase (NRAS) in Glioblastoma

The involvement of non-coding RNAs (ncRNAs) in glioblastoma multiforme (GBM) pathogenesis and progression has been ascertained but their cross-talk within GBM cells remains elusive. We previously demonstrated the role of circSMARCA5 as a tumor suppressor (TS) in GBM. In this paper, we explore the involvement of circSMARCA5 in the control of microRNA (miRNA) expression in GBM. By using TaqMan^® low-density arrays, the expression of 748 miRNAs was assayed in U87MG overexpressing circSMARCA5. Differentially expressed (DE) miRNAs were validated through single TaqMan^® assays in: (i) U87MG overexpressing circSMARCA5; (ii) four additional GBM cell lines (A172; CAS-1; SNB-19; U251MG); (iii) thirty-eight GBM biopsies; (iv) twenty biopsies of unaffected brain parenchyma (UC). Validated targets of DE miRNAs were selected from the databases TarBase and miRTarbase, and the literature; their expression was inferred from the GBM TCGA dataset. Expression was assayed in U87MG overexpressing circSMARCA5, GBM cell lines, and biopsies through real-time PCR. TS miRNAs 126-3p and 515-5p were upregulated following circSMARCA5 overexpression in U87MG and their expression was positively correlated with that of circSMARCA5 (r-values = 0.49 and 0.50, p-values = 9 × 10^-5 and 7 × 10^-5, respectively) in GBM biopsies. Among targets, IGFBP2 (target of miR-126-3p) and NRAS (target of miR-515-5p) mRNAs were positively correlated (r-value = 0.46, p-value = 0.00027), while their expression was negatively correlated with that of circSMARCA5 (r-values = -0.58 and -0.30, p-values = 0 and 0.019, respectively), miR-126-3p (r-value = -0.36, p-value = 0.0066), and miR-515-5p (r-value = -0.34, p-value = 0.010), respectively. Our data identified a new GBM subnetwork controlled by circSMARCA5, which regulates downstream miRNAs 126-3p and 515-5p, and their mRNA targets IGFBP2 and NRAS.

MicroRNAs as Potential Biomarkers in the Differential Diagnosis of Lipomatous Tumors and Their Mimics

Adipocytic tumors are the most common subtype of soft tissue tumors. In current clinical practice, distinguishing benign lipomas from well-differentiated liposarcomas (WDLPS), as well as dedifferentiated liposarcomas (DDLPS) from their morphologic mimics, remains a significant diagnostic challenge. This is especially so when examining small biopsy samples and without the aid of additional ancillary tests. Recognizing the important role that microRNAs (miRNAs) play in tumorigenesis and their potential utility in tumor classification, we analyzed routine clinical tissue samples of benign and malignant lipomatous tumors, as well as other sarcoma mimics, to identify distinguishing miRNA-based signatures that can aid in the differential diagnosis of these entities. We discovered a 6-miRNA signature that separated lipomas from WDLPS with high confidence (AUC of 0.963), as well as a separate 6-miRNA signature that distinguished DDLPS from their more aggressive histologic mimics (AUC of 0.740). Functional enrichment analysis unveiled possible mechanistic involvement of these predictive miRNAs in adipocytic cancer-related biological processes and pathways such as PI3K/AKT/mTOR and MAPK signaling, further supporting the relevance of these miRNAs as biomarkers for adipocytic tumors. Our results demonstrate that miRNA expression profiling may potentially be used as an adjunctive tool for the diagnosis of benign and malignant adipocytic tumors. Further validation studies are warranted.

Tumor-induced escape mechanisms and their association with resistance to checkpoint inhibitor therapy

Immunotherapy aims to activate the immune system to fight cancer in a very specific and targeted manner. Despite the success of different immunotherapeutic strategies, in particular antibodies directed against checkpoints as well as adoptive T-cell therapy, the response of patients is limited in different types of cancers. This attributes to escape of the tumor from immune surveillance and development of acquired resistances during therapy. In this review, the different evasion and resistance mechanisms that limit the efficacy of immunotherapies targeting tumor-associated antigens presented by major histocompatibility complex molecules on the surface of the malignant cells are summarized. Overcoming these escape mechanisms is a great challenge, but might lead to a better clinical outcome of patients and is therefore currently a major focus of research.

The combination of gemcitabine and docetaxel arrests a doxorubicin-resistant dedifferentiated liposarcoma in a patient-derived orthotopic xenograft model

Liposarcoma (LS) is a chemotherapy-resistant disease. The aim of the present study was to find precise therapy for a recurrent dedifferentiated liposarcoma (DDLS) in a patient-derived orthotopic xenograft (PDOX) model. The DDLS PDOX models were established orthotopically in the right inguinal area of nude mice. The DDLS PDOX models were randomized into five groups: untreated; doxorubicin (DOX); gemcitabine (GEM) combined with docetaxel (DOC); pazopanib (PAZ); and yondelis (YON). On day 15, all mice were sacrificed. Measurement of tumor volume and body weight were done two times a week. The DDLS PDOX was resistant to DOX (P > 0.184). YON suppressed tumor growth significantly compared to control group (P < 0.027). However, only GEM combined with DOC arrested the tumor growth (P < 0.001). These findings suggest that GEM combined with DOC has clinical potential for this and possibly other DDLS patients.

Calreticulin as A Novel Potential Metastasis-Associated Protein in Myxoid Liposarcoma, as Revealed by Two-Dimensional Difference Gel Electrophoresis

Myxoid liposarcoma (MLS) is a mesenchymal malignancy. To identify innovate seeds for clinical applications, we examined the proteomes of primary tumor tissues from 10 patients with MLS with different statuses of postoperative metastasis. The protein expression profiles of tumor tissues were created, and proteins with differential expression associated with postoperative metastasis were identified by two-dimensional difference gel electrophoresis (2D-DIGE) and mass spectrometry. The validation was performed using specific antibodies and in vitro analyses. Using 2D-DIGE, we observed 1726 protein species and identified proteins with unique expression levels in metastatic MLS. We focused on the overexpression of calreticulin in metastatic MLS. The higher expression of calreticulin was confirmed by Western blotting, and gene silencing assays demonstrated that reduced expression of calreticulin inhibited cell growth and invasion. Our findings suggested the important roles of calreticulin in MLS metastasis and supported its potential utility as a prognostic biomarker in MLS. Further investigations of the functional properties of calreticulin and other proteins identified in this study will improve our understanding of the biology of MLS and facilitate novel clinical applications.

The Role of the Anti-Aging Protein Klotho in IGF-1 Signaling and Reticular Calcium Leak: Impact on the Chemosensitivity of Dedifferentiated Liposarcomas

By inhibiting Insulin-Like Growth Factor-1-Receptor (IGF-1R) signaling, Klotho (KL) acts like an aging- and tumor-suppressor. We investigated whether KL impacts the aggressiveness of liposarcomas, in which IGF-1R signaling is frequently upregulated. Indeed, we observed that a higher KL expression in liposarcomas is associated with a better outcome for patients. Moreover, KL is downregulated in dedifferentiated liposarcomas (DDLPS) compared to well-differentiated tumors and adipose tissue. Because DDLPS are high-grade tumors associated with poor prognosis, we examined the potential of KL as a tool for overcoming therapy resistance. First, we confirmed the attenuation of IGF-1-induced calcium (Ca²⁺)-response and Extracellular signal-Regulated Kinase 1/2 (ERK1/2) phosphorylation in KL-overexpressing human DDLPS cells. KL overexpression also reduced cell proliferation, clonogenicity, and increased apoptosis induced by gemcitabine, thapsigargin, and ABT-737, all of which are counteracted by IGF-1R-dependent signaling and activate Ca²⁺-dependent endoplasmic reticulum (ER) stress. Then, we monitored cell death and cytosolic Ca²⁺-responses and demonstrated that KL increases the reticular Ca²⁺-leakage by maintaining TRPC6 at the ER and opening the translocon. Only the latter is necessary for sensitizing DDLPS cells to reticular stressors. This was associated with ERK1/2 inhibition and could be mimicked with IGF-1R or MEK inhibitors. These observations provide a new therapeutic strategy in the management of DDLPS.

The Role of Calcium in Differentiation of Human Adipose-Derived Stem Cells to Adipocytes

Differentiation process of mesenchymal stem cells (MSCs) into adipocyte is involved in obesity. Multiple factors such as Ca²⁺ play important roles in different stages of this process. Because of the complicated roles of Ca²⁺ in adipogenesis, the aim of present investigation was to study the influx and efflux of Ca²⁺ into and out of the cells during adipogenesis. Adipose-derived MSCs were used to differentiate into adipocytes. MSCs were exposed to 2.5 mM Ca²⁺ or 1.8 mM Ca²⁺ plus calcium ionophore, A23187, for 3 days. Lipid staining, triglycerides (TG) content, and glyceraldehyde phosphate dehydrogenase (GAPDH) activity were evaluated to confirm the efficiency of the differentiation. Gene expression of GLUT4, PPARγ2, RAR-α, and calreticulin, as well as the protein levels of GLUT4 and PPARγ2 were determined. Ca²⁺ and in particular Ca²⁺ plus A23187 significantly lowered the efficiency of differentiation accompanied by decrease in intracellular TG deposits, GAPDH activity and alleviation of gene, and protein levels of GLUT4 and PPARγ2. While calreticulin and RAR-α were remarkably upregulated in A23187 group. This study showed the inhibitory effects of calcium in adipogenesis. Additionally, it indicated the greater inhibitory effect of calreticulin and RAR-α in controlling adipogenesis by higher levels of calcium.

Genome-wide miRNA response to anacardic acid in breast cancer cells

MicroRNAs are biomarkers and potential therapeutic targets for breast cancer. Anacardic acid (AnAc) is a dietary phenolic lipid that inhibits both MCF-7 estrogen receptor α (ERα) positive and MDA-MB-231 triple negative breast cancer (TNBC) cell proliferation with IC50s of 13.5 and 35 μM, respectively. To identify potential mediators of AnAc action in breast cancer, we profiled the genome-wide microRNA transcriptome (microRNAome) in these two cell lines altered by the AnAc 24:1n5 congener. Whole genome expression profiling (RNA-seq) and subsequent network analysis in MetaCore Gene Ontology (GO) algorithm was used to characterize the biological pathways altered by AnAc. In MCF-7 cells, 69 AnAc-responsive miRNAs were identified, e.g., increased let-7a and reduced miR-584. Fewer, i.e., 37 AnAc-responsive miRNAs were identified in MDA-MB-231 cells, e.g., decreased miR-23b and increased miR-1257. Only two miRNAs were increased by AnAc in both cell lines: miR-612 and miR-20b; however, opposite miRNA arm preference was noted: miR-20b-3p and miR-20b-5p were upregulated in MCF-7 and MDA-MB-231, respectively. miR-20b-5p target EFNB2 transcript levels were reduced by AnAc in MDA-MB-231 cells. AnAc reduced miR-378g that targets VIM (vimentin) and VIM mRNA transcript expression was increased in AnAc-treated MCF-7 cells, suggesting a reciprocal relationship. The top three enriched GO terms for AnAc-treated MCF-7 cells were B cell receptor signaling pathway and ribosomal large subunit biogenesis and S-adenosylmethionine metabolic process for AnAc-treated MDA-MB-231 cells. The pathways modulated by these AnAc-regulated miRNAs suggest that key nodal molecules, e.g., Cyclin D1, MYC, c-FOS, PPARγ, and SIN3, are targets of AnAc activity.

Recent translational research into targeted therapy for liposarcoma

Liposarcomas (LPS) are among the most common soft tissue sarcomas, originating from adipocytes. Treatment for LPS typically involves surgical resection and radiation therapy, while the use of conventional cytotoxic chemotherapy for unresectable or metastatic LPS remains controversial. This review summarizes the results of recent translational research and trials of novel therapies targeting various genetic and molecular aberrations in different subtypes of LPS. Genetic aberrations such as the 12q13-15 amplicon, genetic amplification of MDM2, CDK4, TOP2A, PTK7, and CHEK1, point mutations in CTNNB1, CDH1, FBXW7, and EPHA1, as the fusion of FUS-DDIT3/EWSR1-DDIT3 are involved in the pathogenesis LPS and represent potential therapeutic candidates. Tyrosine kinase inhibitors targeting MET, AXL, IGF1R, EGFR, VEGFR2, PDGFR-β and Aurora kinase are effective in certain types of LPS. Abnormalities in the PI3K/Akt signaling pathway deregulation of C/EBP-α and its partner PPAR-γ, and the interaction between calreticulin (CRT) and CD47 are also promising therapeutic targets. These promising new approaches may help to supplement existing treatments for LPS.

Resistance to anticancer vaccination effect is controlled by a cancer cell-autonomous phenotype that disrupts immunogenic phagocytic removal

Immunogenic cell death (ICD) is a well-established instigator of ‘anti-cancer vaccination-effect (AVE)’. ICD has shown considerable preclinical promise, yet there remain subset of cancer patients that fail to respond to clinically-applied ICD inducers. Non-responsiveness to ICD inducers could be explained by the existence of cancer cell-autonomous, anti-AVE resistance mechanisms. However such resistance mechanisms remain poorly investigated. In this study, we have characterized for the first time, a naturally-occurring preclinical cancer model (AY27) that exhibits intrinsic anti-AVE resistance despite treatment with ICD inducers like mitoxantrone or hypericin-photodynamic therapy. Further mechanistic analysis revealed that this anti-AVE resistance was associated with a defect in exposing the important ‘eat me’ danger signal, surface-calreticulin (ecto-CRT/CALR). In an ICD setting, this defective ecto-CRT further correlated with severely reduced phagocytic clearance of AY27 cells as well as the failure of these cells to activate AVE. Defective ecto-CRT in response to ICD induction was a result of low endogenous CRT protein levels (i.e. CRT^low-phenotype) in AY27 cells. Exogenous reconstitution of ecto-rCRT (recombinant-CRT) improved the phagocytic removal of ICD inducer-treated AY27 cells, and importantly, significantly increased their AVE-activating ability. Moreover, we found that a subset of cancer patients of various cancer-types indeed possessed CALR^low or CRT^low-tumours. Remarkably, we found that tumoural CALR^high-phenotype was predictive of positive clinical responses to therapy with ICD inducers (radiotherapy and paclitaxel) in lung and ovarian cancer patients, respectively. Furthermore, only in the ICD clinical setting, tumoural CALR levels positively correlated with the levels of various phagocytosis-associated genes relevant for phagosome maturation or processing. Thus, we reveal the existence of a cancer cell-autonomous, anti-AVE or anti-ICD resistance mechanism that has profound clinical implications for anticancer immunotherapy and cancer predictive biomarker analysis.

Transcriptome profiling identifies p53 as a key player during calreticulin deficiency: Implications in lipid accumulation

Calreticulin (CRT) is an endoplasmic reticulum (ER) resident calcium binding protein that is involved in several cellular activities. Transcriptome analyses in CRT knockdown HepG2 cells revealed 253 altered unique genes and subsequent in silico protein-protein interaction network and MCODE clustering identified 34 significant clusters, of which p53 occupied the central hub node in the highest node-rich cluster. Toward validation, we show that CRT knockdown leads to inhibition of p53 protein levels. Both, CRT and p53 siRNA promote hepatic lipid accumulation and this was accompanied by elevated SREBP-1c and FAS levels. p53 was identified to bind at -219 bp on the SREBP-1c promoter and in the presence of CRT siRNA, there was decreased occupancy of p53 on this binding element. This was associated with increased SREBP-1c promoter activity and both, mutation in this binding site or p53 over-expression antagonised the effects of CRT knockdown. We, therefore, identify a negatively regulating p53 binding site on the SREBP-1c promoter that is critical during hepatic lipid accumulation. These results were validated in mouse primary hepatocytes and toward a physiological relevance, we report that while the levels of CRT and p53 are reduced in the fatty livers of diabetic db/db mice, SREBP-1c levels are significantly elevated. Our results suggest that decreased CRT levels might be involved in the development of a fatty liver by preventing p53 occupancy on the SREBP-1c promoter and thereby facilitating SREBP-1c up-regulation and consequently, lipid accumulation.

Differentially expressed proteins in nitric oxide-stimulated NIH/3T3 fibroblasts: implications for inhibiting cancer development

PURPOSE

Recent evidence shows that nitric oxide (NO) may exhibit both pro-cancer and anti-cancer activities. The present study aimed to determine the differentially expressed proteins in NO-treated NIH/3T3 fibroblasts in order to investigate whether NO induces proteins with pro-cancer or anti-cancer effects.

MATERIALS AND METHODS

The cells were treated with 300 μM of an NO donor 3,3-bis-(aminoethyl)-1-hydroxy-2-oxo-1-triazene (NOC-18) for 12 h. The changed protein patterns, which were separated by two-dimensional electrophoresis using pH gradients of 4-7, were conclusively identified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF MS) analysis of the peptide digests.

RESULTS

Seventeen differentially expressed proteins were identified in NOC-18-treated cells. Nine proteins [vinculin protein, keratin 19, ubiquitous tropomodulin, F-actin capping protein (α1 subunit), tropomyosin 3, 26S proteasome-associated pad1 homolog, T-complex protein 1 (ε subunit) N(G)-dimethylarginine dimethylaminohydrolase, and heat shock protein 90] were increased and eight proteins (heat shock protein 70, glucosidase II, lamin B1, calreticulin, nucleophosmin 1, microtubule-associated protein retinitis pigmentosa/end binding family member 1, 150 kD oxygen-regulated protein precursor, and heat shock 70-related protein albino or pale green 2) were decreased by NOC-18 in the cells. Thirteen proteins are related to the suppression of cancer cell proliferation, invasion, and metastasis while two proteins (heat shock protein 90 and N(G)-dimethylarginine dimethylaminohydrolase) are related to carcinogenesis. The functions of 150 kD oxygen-regulated protein precursor and T-complex protein 1 (ε subunit) are unknown in relation to carcinogenesis.

CONCLUSION

Most proteins differentially expressed by NOC-18 are involved in inhibiting cancer development.

Advances in the targeted therapy of liposarcoma

Liposarcoma (LPS) is the most common type of soft-tissue sarcoma. Complete surgical resection is the only curative means for localized disease; however, both radiation and conventional cytotoxic chemotherapy remain controversial for metastatic or unresectable disease. An increasing number of trials with novel targeted therapy of LPS have provided encouraging data during recent years. This review will provide an overview of the advances in our understanding of LPS and summarize the results of recent trials with novel therapies targeting different genetic and molecular aberrations for different subtypes of LPS.

MicroRNAs in soft tissue sarcomas: overview of the accumulating evidence and importance as novel biomarkers

Sarcomas are distinctly heterogeneous tumors and a variety of subtypes have been described. Although several diagnostic explorations in the past three decades, such as identification of chromosomal translocation, have greatly improved the diagnosis of soft tissue sarcomas, the unsolved issues, including the limited useful biomarkers, remain. Emerging reports on miRNAs in soft tissue sarcomas have provided clues to solving these problems. Evidence of circulating miRNAs in patients with soft tissue sarcomas and healthy individuals has been accumulated and is accelerating their potential to develop into clinical applications. Moreover, miRNAs that function as novel prognostic factors have been identified, thereby facilitating their use in miRNA-targeted therapy. In this review, we provide an overview of the current knowledge on miRNA deregulation in soft tissue sarcomas, and discuss their potential as novel biomarkers and therapeutics.

MicroRNA expression profiles distinguish liposarcoma subtypes and implicate miR-145 and miR-451 as tumor suppressors

Liposarcomas are rare, heterogeneous and malignant tumors that can be divided into four histological subtypes with different characteristics and clinical behavior. Treatment consists of surgery in combination with systemic chemotherapy, but nevertheless mortality rates are high. More insight into the biology of liposarcoma tumorigenesis is needed to devise novel therapeutic approaches. MicroRNAs (miRNAs) have been associated with carcinogenesis in many tumors and may function as tumor suppressor or oncogene. In this study we examined miRNA expression in an initial series of 57 human liposarcomas (including all subtypes), lipomas and normal fat by miRNA microarrays. Supervised hierarchical clustering of the most differentially expressed miRNAs (p < 0.0002) distinguished most liposarcoma subtypes and control tissues. The distinction between well differentiated liposarcomas and benign lipomas was blurred, suggesting these tumor types may represent a biological continuum. MiRNA signatures of liposarcoma subtypes were established and validated in an independent series of 58 liposarcomas and control tissues. The expression of the miR-143/145 and miR-144/451 cluster members was clearly reduced in liposarcomas compared to normal fat. Overexpression of miR-145 and miR-451 in liposarcoma cell lines decreased cellular proliferation rate, impaired cell cycle progression and induced apoptosis. In conclusion, we show that miRNA expression profiling can be used to discriminate liposarcoma subtypes, which can possibly aid in objective diagnostic decision making. In addition, our data indicate that miR-145 and miR-451 act as tumor suppressors in adipose tissue and show that re-expression of these miRNAs could be a promising therapeutic strategy for liposarcomas.

A panel of tumor markers, calreticulin, annexin A2, and annexin A3 in upper tract urothelial carcinoma identified by proteomic and immunological analysis

Background

Upper tract urothelial carcinoma (UTUC) is a tumor with sizable metastases and local recurrence. It has a worse prognosis than bladder cancer. This study was designed to investigate the urinary potential tumor markers of UTUC.

Methods

Between January 2008 and January 2009, urine was sampled from 13 patients with UTUC and 20 healthy adults. The current study identified biomarkers for UTUC using non-fixed volume stepwise weak anion exchange chromatography for fractionation of urine protein prior to two-dimensional gel electrophoresis.

Results

Fifty five differential proteins have been determined by comparing with the 2-DE maps of the urine of UTUC patients and those of healthy people. Western blotting analysis and immunohistochemistry of tumor tissues and normal tissues from patients with UTUC were carried out to further verify five possible UTUC biomarkers, including zinc-alpha-2-glycoprotein, calreticulin, annexin A2, annexin A3 and haptoglobin. The data of western blot and immunohistochemical analysis are consistent with the 2-DE data. Combined the experimental data in the urine and in tumor tissues collected from patients with UTUC, the crucial over-expressed proteins are calreticulin, annexin A2, and annexin A3.

Conclusions

Calreticulin, annexin A2, and annexin A3 are very likely a panel of biomarkers with potential value for UTUC diagnosis.

Predicting dedifferentiation in liposarcoma: a proteomic approach

There are no known morphologic characteristics, cytogenetic aberrations, or molecular alterations predictive of dedifferentiation in liposarcomas. Identification of such a prognostic marker could potentially affect surgical and adjuvant therapy and/or follow-up surveillance for these patients. Two-dimensional difference gel electrophoresis was utilized to characterize protein expression patterns in lipoma, atypical lipomatous tumor (ALT), and the well-differentiated components of dedifferentiated liposarcoma (DDL). Protein spots were identified by peptide mapping/fingerprinting using matrix-assisted laser desorption ionization time-of-flight mass spectrometry. No significant differences in protein expression were identified between lipoma and ALT or DDL. Proteins that were significantly down-regulated in the well-differentiated component of DDL compared to ALT included mitochondrial aldehyde dehydrogenase 2 (ALDH2, >3-fold reduction) and selenium-binding protein-1 (SELENBP1, >4-fold reduction). Subsequent validation studies were performed by immunohistochemistry (IHC) on a separate series of ALT (n = 30) and the well-differentiated components of DDL (n = 28). IHC stains were evaluated in a semi-quantitative manner, and the results were analyzed using the Mann-Whitney test and receiver-operator curve analysis. Decreased IHC staining for SELENBP1 in the well-differentiated component of DDL was confirmed. Cytoplasmic ALDH2 levels determined by IHC were not significantly different in ALT and DDL; no nuclear staining for ALDH2 was observed. Expression of SELENBP1 is decreased in the well-differentiated component of DDL compared to ALT. However, variability in the staining patterns in liposarcoma precludes its use as a predictive marker for dedifferentiation.