Heterogeneous in vitro effects of doxorubicin on gene expression in primary human liposarcoma cultures

Comparison of primary and passaged tumor cell cultures and their application in personalized medicine

Passaged cell lines represent currently an integral component in various studies of malignant neoplasms. These cell lines are utilized for drug screening both in monolayer cultures or as part of three-dimensional (3D) tumor models. They can also be used to model the tumor microenvironment in vitro and in vivo through xenotransplantation into immunocompromised animals. However, immortalized cell lines have some limitations of their own. The homogeneity of cell line populations and the extensive passaging in monolayer systems make these models distant from the original disease. Recently, there has been a growing interest among scientists in the use of primary cell lines, as these are passaged directly from human tumor tissues. In this case, cells retain the morphological and functional characteristics of the tissue from which they were derived, an advantage often not observed in passaged cultures. This review highlights the advantages and limitations of passaged and primary cell cultures, their similarities and differences, as well as existing test systems that are based on primary and passaged cell cultures for drug screening purposes.

Coagulation factor V in breast cancer: a p53-regulated tumor suppressor and predictive marker for treatment response to chemotherapy

BACKGROUND

Patients with cancer are at an increased risk of developing coagulation complications, and chemotherapy treatment increases the risk. Tumor progression is closely linked to the hemostatic system. Breast cancer tumors express coagulation factor V (FV), an essential factor in blood coagulation. The functional role of FV during treatment with chemotherapy is poorly understood and was explored in this study.

OBJECTIVES

We aimed to investigate the role of FV in breast cancer progression by exploring associations with treatment response, gene regulation, and the functional effects of FV.

METHODS

The receiver operating characteristic plotter was used to explore the predictive value of FV mRNA (F5) expression for treatment with FEC (5-fluorouracil, anthracycline, and cyclophosphamide). Breast cancer cohorts were analyzed to study treatment response to FEC. The effect of chemotherapy on F5 expression, the regulation of F5, and the functional effects of FV dependent and independent of chemotherapy were studied in breast cancer cell lines.

RESULTS

F5 tumor expression was significantly higher in responders to FEC than in nonresponders. In vitro experiments revealed that anthracycline treatment increased the expression of F5. Inhibition and knockdown of p53 reduced the anthracycline-induced F5 expression. Mutation of a p53 half-site (c.158+1541/158+1564) in a luciferase plasmid reduced luciferase activity, suggesting that p53 plays a role in regulating F5. FV overexpression increased apoptosis and reduced proliferation slightly during anthracycline treatment.

CONCLUSION

Our study identified F5 as a p53-regulated tumor suppressor candidate and a promising marker for response to chemotherapy. FV may have functional effects that are therapeutically relevant in breast cancer.

DNA methylation-mediated epigenetic regulation of oncogenic RPS2 as a novel therapeutic target and biomarker in hepatocellular carcinoma

Ribosomal Protein S2 (RPS2) has emerged as a potential prognostic biomarker due to its involvement in key cellular processes and its altered expression pattern in certain types of cancer. However, its role in hepatocellular carcinoma (HCC) has yet to be investigated. Herein, we analyzed RPS2 mRNA expression and promoter methylation in HCC patient samples and HepG2 cells. Subsequently, loss-of-function experiments were conducted to determine the function of RPS2 in HCC cells in vitro. Our results revealed that RPS2 mRNA expression is significantly elevated, and its promoter is hypomethylated in HCC patient samples compared to controls. In addition, 5-Azacytidine treatment in HepG2 cells decreased RPS2 promoter methylation level and increased its mRNA expression. RPS2 knockdown in HepG2 cells suppressed cell proliferation and promoted apoptosis. Functional pathway analysis of genes positively and negatively associated with RPS2 expression in HCC showed enrichment in ribosomal biogenesis, translation machinery, cell cycle regulation, and DNA processing. Furthermore, utilizing drug-protein 3D docking, we found that doxorubicin, sorafenib, and 5-Fluorouracil, showed high affinity to the active sites of RPS2, and in vitro treatment with these drugs reduced RPS2 expression. For the first time, we report on DNA methylation-mediated epigenetic regulation of RPS2 and its oncogenic role in HCC. Our findings suggest that RPS2 plays a significant role in the development and progression of HCC, hence its potential prognostic and therapeutic utility. Moreover, as epigenetic changes happen early in cancer development, RPS2 may serve as a potential biomarker for tumor progression.

Emerging role of zinc finger protein A20 as a suppressor of hepatocellular carcinoma

Hepatocellular carcinoma (HCC), the third leading cause of cancer-associated mortality worldwide, is a major public health problem. Zinc finger protein A20 (A20), an acute phase response gene, is a potent inhibitor of NF-κB signaling. A20 serves a critical role in liver protection, including limiting inflammation following hepatic injury, stimulating hepatocyte growth, and preventing hepatic ischemia-reperfusion injury. A20 is also involved in different processes, including tumorigenesis, progression, and metastasis through multiple mechanisms. Accumulated studies have reported the clinical implications and biological relevance of A20 in the development and progression of HCC. The underlying mechanisms of A20 in HCC include inhibition of epithelial-mesenchymal transition, protein tyrosine kinase 2 activation and Rac family GTPase 1 activity. Combining liver protection with tumor inhibition is a unique advantage of A20, which has the potential to be a novel treatment for promoting liver regeneration following liver resection in patients with HCC with liver cirrhosis. This review discusses the hepato-protective effect of A20 on hepatocytes and its potential role in cancer development, particularly its suppressor effect on HCC.

Combination therapy with c-met inhibitor and TRAIL enhances apoptosis in dedifferentiated liposarcoma patient-derived cells

Background

Liposarcoma (LPS) is a tumor derived from adipose tissue, and has the highest incidence among soft tissue sarcomas. Dedifferentiated liposarcoma (DDLPS) is a malignant tumor with poor prognosis. Recurrence and metastasis rates in LPS remain high even after chemotherapy and radiotherapy following complete resection. Therefore, the development of advanced treatment strategies for LPS is required. In the present study, we investigated the effect of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) treatment, and of combination treatment using TRAIL and a c-Met inhibitor on cell viability and apoptosis in LPS and DDLPS cell lines of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) treatment, and of combination treatment using TRAIL and a c-Met inhibitor.

Methods

We analyzed cell viability after treatment with TRAIL and a c-Met inhibitor by measuring CCK8 and death receptor 5 (DR5) expression levels via fluorescence activated cell sorting (FACS) in both sarcoma cell lines and DDLPS patient-derived cells (PDCs). Moreover, we validated the effects of TRAIL alone and in combination with c-Met inhibitor on apoptosis in LPS cell lines and DDLPS PDCs via FACS.

Results

Our results revealed that combination treatment with a c-Met inhibitor and human recombinant TRAIL (rhTRAIL) suppressed cell viability and induced cell death in both sarcoma cell lines and DDLPS PDCs, which showed varying sensitivities to rhTRAIL alone. Also, we confirmed that treatment with a c-Met inhibitor upregulated DR5 levels in sarcoma cell lines and DDLPS PDCs. In both TRAIL-susceptible and TRAIL-resistant cells subjected to combination treatment, promotion of apoptosis was dependent on DR5 upregulation.

Conclusion

From these results, our findings validated that DR5 up-regulation caused by combination therapy with a c-Met inhibitor and rhTRAIL enhanced TRAIL sensitization and promoted apoptosis. We propose the use of this approach to overcome TRAIL resistance and serve as a novel treatment strategy for clinical trials.

Electronic supplementary material

The online version of this article (10.1186/s12885-019-5713-2) contains supplementary material, which is available to authorized users.

Establishment of a Novel PDX Mouse Model and Evaluation of the Tumor Suppression Efficacy of Bortezomib Against Liposarcoma

The patient-derived xenograft (PDX) model has been adopted as a major tool for studying tumorigenesis and differentiation in various carcinomas. In addition, it has been used in the development of anticancer agents. PDX models have been among the most meaningful tools used to understand the role of stromal cells and vascular cells in the body, which are major factors in cancer development and the application of therapeutic agents. Also, the establishment of PDX models from liposarcoma patients is considered to be important for understanding lipomagenesis and following drugs development. For these reasons, we developed patient-derived cell (PDC) and PDX models derived from 20 liposarcoma patients. The tissues of these patients were obtained in accordance with the principles of the Samsung Medical Center's ethics policy, and cell culture and xenografting onto the mice were performed under these principles. High-throughput drug screening (HTS) was carried out using established PDCs to select candidate drugs. Among the different candidate anticancer drugs, we tested the effect of bortezomib, which was expected to inhibit MDM2 amplification. First, we confirmed that the PDCs maintained the characteristics of liposarcoma cells by assessing MDM2 amplification and CDK4 overexpression using fluorescence in situ hybridization. Analysis of short tandem repeats and an array using comparative genomic hybridization confirmed that the PDX model exhibited the same genomic profile as that of the patient. Immunohistochemistry for MDM2 and CDK4 showed that the overexpression patterns of both proteins were similar in the PDX models and the PDCs. Specifically, MDM2 amplification was observed to be significantly correlated with the successful establishment of PDX mouse models. However, CDK4 expression did not show such a correlation. Of the anticancer drugs selected through HTS, bortezomib showed a strong anticancer effect against PDC. In addition, we observed that bortezomib suppressed MDM2 expression in a dose-dependent manner. In contrast, p21 tended to elicit an increase in PDC expression. Treatment of the PDX model with bortezomib resulted in an anticancer effect similar to that seen in the PDCs. These results support that PDCs and PDX models are among the most powerful tools for the development and clinical application of anticancer drugs for the treatment of liposarcoma patients.

Comprehensive Bioinformatic Analysis Genes Associated to the Prognosis of Liposarcoma

BACKGROUND Liposarcoma is the most common type of soft tissue sarcoma, but its molecular mechanism is poorly defined. This study aimed to identify genes crucial to the pathogenesis of liposarcoma and to explore their functions, related pathways, and prognostic value. MATERIAL AND METHODS Differentially expressed genes (DEGs) in the GSE59568 dataset were screened. Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis were conducted to investigate the DEGs at the functional level. Protein-protein interaction (PPI) networks and module analysis were applied to identify hub genes from among the DEGs. The GSE30929 dataset was used to validate the relationship between hub genes and the distant recurrence-free survival (DRFS) of liposarcoma patients using Cox model analysis. RESULTS A total of 1111 DEGs were identified. GO and KEGG pathway analysis indicated that the DEGs were mainly associated with lipopolysaccharides and pathways in cancer. The PPI network and module analysis identified 10 hub genes from the DEG network. The Cox model identified 3 genes (NIP7, RPL10L, and MCM2) significantly associated with DRFS. The risk score calculated by the Cox model of the NIP7-RPL10L-MCM2 signature could largely predict the 1-, 3-, and 5-year DRFS of liposarcoma patients, and the prognostic value was even higher for subtypes of liposarcoma. CONCLUSIONS This study identified genes that might play critical roles in liposarcoma pathogenesis as well as a 3-gene-based signature that could be used as a candidate prognostic biomarker for patients with liposarcoma.

Doxorubicin induces an extensive transcriptional and metabolic rewiring in yeast cells

Doxorubicin is one of the most effective chemotherapy drugs used against solid tumors in the treatment of several cancer types. Two different mechanisms, (i) intercalation of doxorubicin into DNA and inhibition of topoisomerase II leading to changes in chromatin structure, (ii) generation of free radicals and oxidative damage to biomolecules, have been proposed to explain the mode of action of this drug in cancer cells. A genome-wide integrative systems biology approach used in the present study to investigate the long-term effect of doxorubicin in Saccharomyces cerevisiae cells indicated the up-regulation of genes involved in response to oxidative stress as well as in Rad53 checkpoint sensing and signaling pathway. Modular analysis of the active sub-network has also revealed the induction of the genes significantly associated with nucleosome assembly/disassembly and DNA repair in response to doxorubicin. Furthermore, an extensive re-wiring of the metabolism was observed. In addition to glycolysis, and sulfate assimilation, several pathways related to ribosome biogenesis/translation, amino acid biosynthesis, nucleotide biosynthesis, de novo IMP biosynthesis and one-carbon metabolism were significantly repressed. Pentose phosphate pathway, MAPK signaling pathway biological processes associated with meiosis and sporulation were found to be induced in response to long-term exposure to doxorubicin in yeast cells.

Could miRNA Signatures be Useful for Predicting Uterine Sarcoma and Carcinosarcoma Prognosis and Treatment?

Changes in microRNA (miRNA) expression may lead to cancer development and/or contribute to its progression; however, their role in uterine sarcomas is poorly understood. Uterine sarcomas (US) belong to a rare class of heterogeneous tumors, representing about 1% of all gynecologic neoplasms. This study aimed to assess the expression profile of 84 cancer-related miRNAs and to evaluate their correlation with clinical pathological features. Eighty-two formalin-fixed paraffin-embedded (FFPE) samples were selected. In leiomyosarcoma (LMS), there was an association of lower cancer-specific survival (CSS) with the downregulation of miR-125a-5p and miR-10a-5p, and the upregulation of miR-196a-5p and miR-34c-5p. In carcinosarcoma (CS), lower CSS was associated with the upregulation of miR-184, and the downregulation of let-7b-5p and miR-124. In endometrial stromal sarcomas (ESS), the upregulation of miR-373-3p, miR-372-3p, and let-7b-5p, and the down-expression of let-7f-5p, miR-23-3p, and let-7b-5p were associated with lower CSS. Only miR-138-5p upregulation was associated with higher survival rates. miR-335-5p, miR-301a-3p, and miR-210-3p were more highly expressed in patients with tumor metastasis and relapse. miR-138-5p, miR-146b-5p, and miR-218-5p expression were associated with higher disease-free survival (DFS) in treated patients. These miRNAs represent potential prediction markers for prognosis and treatment response in these tumors.

Establishment of a Primary Culture of Patient-derived Soft Tissue Sarcoma

Soft tissue sarcomas (STS) represent a spectrum of heterogeneous malignancies with a difficult diagnosis, classification, and management. To date, more than 50 histological subtypes of these rare solid tumors have been identified. Thus, due to their extraordinary diversity and low incidence, our understanding of the biology of these tumors is still limited. Patient-derived cultures represent the ideal platform to study STS pathophysiology and pharmacology. We thus developed a human preclinical model of STS starting from tumor specimens harvested from patients undergoing surgical resection. Patient-derived STS cell cultures were obtained from the surgical specimens by collagenase digestion and isolated by filtration. Cells were counted, seeded, and left for 14 days in standard monolayer cultures and then processed by downstream analysis. Before performing molecular or pharmaceutical analyses, the establishment of STS primary cultures was confirmed through the evaluation of cytomorphologic features and, when available, immunohistochemical markers. This method represents a useful tool 1) to study the natural history of these poorly explored malignancies and 2) to test the effects of different drugs in an effort to learn more about their mechanisms of action.

Management and potentialities of primary cancer cultures in preclinical and translational studies

The use of patient-derived primary cell cultures in cancer preclinical assays has increased in recent years. The management of resected tumor tissue remains complex and a number of parameters must be respected to obtain complete sample digestion and optimal vitality yield. We provide an overview of the benefits of correct primary cell culture management using different preclinical methodologies, and describe the pros and cons of this model with respect to other kinds of samples. One important advantage is that the heterogeneity of the cell populations composing a primary culture partially reproduces the tumor microenvironment and crosstalk between malignant and healthy cells, neither of which is possible with cell lines. Moreover, the use of patient-derived specimens in innovative preclinical technologies, such as 3D systems or bioreactors, represents an important opportunity to improve the translational value of the results obtained. In vivo models could further our understanding of the crosstalk between tumor and other tissues as they enable us to observe the systemic and biological interactions of a complete organism. Although engineered mice are the most common model used in this setting, the zebrafish (Danio rerio) species has recently been recognized as an innovative experimental system. In fact, the transparent body and incomplete immune system of zebrafish embryos are especially useful for evaluating patient-derived tumor tissue interactions in healthy hosts. In conclusion, ex vivo systems represent an important tool for cancer research, but samples require correct manipulation to maximize their translational value.

Activity of Eribulin in a Primary Culture of Well-Differentiated/Dedifferentiated Adipocytic Sarcoma

Eribulin mesylate is a novel, non-taxane, synthetic microtubule inhibitor showing antitumor activity in a wide range of tumors including soft tissue sarcomas (STS). Eribulin has been recently approved for the treatment of metastatic liposarcoma (LPS) patients previously treated with anthracyclines. This work investigated the mechanism of action of this innovative antitubulin agent in well-differentiated/dedifferentiated LPS (ALT/DDLPS) which represents one of the most common adipocytic sarcoma histotypes. A primary culture of ALT/DDLPS from a 54-year-old patient was established. The anticancer activity of eribulin on the patient-derived primary culture was assessed by MTT and tunel assays. Eribulin efficacy was compared to other drugs approved for the treatment of STS. Cell migration and morphology were examined after exposure to eribulin to better understand the drug mechanism of action. Finally, Western blot analysis of apoptosis and migration proteins was performed. The results showed that eribulin exerts its antiproliferative effect by the arrest of cell motility and induction of apoptosis. Our results highlighted the activity of eribulin in the treatment of ALT/DDLPS patients.

Mechanisms and in vitro effects of cepharanthine hydrochloride: Classification analysis of the drug-induced differentially-expressed genes of human nasopharyngeal carcinoma cells

Nasopharyngeal carcinoma (NPC) is the most commonly diagnosed head and neck malignancy and is prevalent worldwide. Previous studies have demonstrated the antitumor properties of cepharanthine hydrochloride (CH) in several human cancer cells. However, the action of CH in NPC cells has yet to be determined. In the present study, we investigated the effects of CH in human NPC cell lines including CNE-1 and CNE-2 on cell growth and apoptosis in vitro. Using MTT and ATP-tumor chemosensitivity assays it was found that CH inhibited cell viability. Additionally, flow cytometric and analysis electron microscopy revealed the inhibition of cell cycle progression and reduction of apoptosis, respectively, in human NPC cell lines including CNE-1 and CNE-2 in vitro. To identify the potential action mechanisms of CH, the cDNA microarray analysis results were confirmed by quantitative PCR analysis using a number of genes, including CDKN1A/P21, NR4A1/TR3 and DAXX. In total, 138 upregulated and 63 downregulated genes in CNE-2 cells were treated with CH. According to their biological function, the genes were classified as: i) cell cycle-related genes; ii) DNA repair‑related genes; iii) apoptosis-related genes and iv) nuclear factor-κB (NF-κB) transcription factors signal pathways. The results of the present study showed that CH is a potential therapeutic agent against human NPC, and provide rational explanations and a scientific basis for the study of the development of CH in the treatment of NPC.

Functional genomics analysis reveals a MYC signature associated with a poor clinical prognosis in liposarcomas

Liposarcomas, which are malignant fatty tumors, are the second most common soft-tissue sarcomas. Several histologically defined liposarcoma subtypes exist, yet little is known about the molecular pathology that drives the diversity in these tumors. We used functional genomics to classify a panel of diverse liposarcoma cell lines based on hierarchical clustering of their gene expression profiles, indicating that liposarcoma gene expression profiles and histologic classification are not directly correlated. Boolean probability approaches based on cancer-associated properties identified differential expression in multiple genes, including MYC, as potentially affecting liposarcoma signaling networks and cancer outcome. We confirmed our method with a large panel of lipomatous tumors, revealing that MYC protein expression is correlated with patient survival. These data encourage increased reliance on genomic features in conjunction with histologic features for liposarcoma clinical characterization and lay the groundwork for using Boolean-based probabilities to identify prognostic biomarkers for clinical outcome in tumor patients.

Phosphoprotein enriched in astrocytes (PEA)-15: a potential therapeutic target in multiple disease states

Phosphoprotein enriched in astrocytes-15 (PEA-15) is a cytoplasmic protein that sits at an important junction in intracellular signalling and can regulate diverse cellular processes, such as proliferation and apoptosis, dependent upon stimulation. Regulation of these processes occurs by virtue of the unique interaction of PEA-15 with other signalling proteins. PEA-15 acts as a cytoplasmic tether for the mitogen-activated protein kinases, extracellular signal-regulated kinase 1/2 (ERK1/2) preventing nuclear localisation. In order to release ERK1/2, PEA-15 requires to be phosphorylated via several potential pathways. PEA-15 (and its phosphorylation state) therefore regulates many ERK1/2-dependent processes, including proliferation, via regulating ERK1/2 nuclear translocation. In addition, PEA-15 contains a death effector domain (DED) which allows interaction with other DED-containing proteins. PEA-15 can bind the DED-containing apoptotic adaptor molecule, Fas-associated death domain protein (FADD) which is also dependent on the phosphorylation status of PEA-15. PEA-15 binding of FADD can inhibit apoptosis as bound FADD cannot participate in the assembly of apoptotic signalling complexes. Through these protein–protein interactions, PEA-15-regulated cellular effects have now been investigated in a number of disease-related studies. Changes in PEA-15 expression and regulation have been observed in diabetes mellitus, cancer, neurological disorders and the cardiovascular system. These changes have been suggested to contribute to the pathology related to each of these disease states. As such, new therapeutic targets based around PEA-15 and its associated interactions are now being uncovered and could provide novel avenues for treatment strategies in multiple diseases.

Suppression of tumor and metastasis progression through the scaffolding functions of SSeCKS/Gravin/AKAP12

Scaffolding proteins such as SSeCKS/Gravin/AKAP12 ("AKAP12") are thought to control oncogenic signaling pathways by regulating key mediators in a spatiotemporal manner. The downregulation of AKAP12 in many human cancers, often associated with promoter hypermethylation, or the loss of its locus at 6q24-25.2, correlates with progression to malignancy and metastasis. The forced re-expression of AKAP12 in cancer cell lines suppresses in vitro parameters of oncogenic growth, invasiveness, and cell motility through its ability to scaffold protein kinase C (PKC), F-actin, cyclins, Src, and phosphoinositides, and possibly through additional scaffolding domains for PKA, calmodulin, β1,4-galactosyltransferase-polypeptide-1, β2-adrenergic receptors, and cAMP-specific 3',5'-cyclic phosphodiesterase 4D. Moreover, AKAP12 re-expression in tumor models results in metastasis suppression through the inhibition of Src-regulated, VEGF-mediated neovascularization at distal sites. The current review will describe the emerging understanding of how AKAP12 regulates cellular senescence and oncogenic progression at the level of tumor cells and tumor-associated microenvironment via its multiple scaffolding functions.

RNA interference (RNAi) of Ufd1 protein can sensitize a hydroxycamptothecin-resistant colon cancer cell line SW1116/HCPT to hydroxycamptothecin

OBJECTIVE

To investigate whether RNA interference (RNAi) of the ubiquitin fusion-degradation 1-like protein (Ufd1) could sensitize hydroxycamptothecin (HCPT)-resistant colon cancer cell line SW1116/HCPT to the cytotoxic effect of HCPT.

METHODS

SW1116/HCPT cells were transfected with plasmids containing Ufd1-specific small interfering RNA (siRNA) (Ufd1 knockdown cells) and non-specific siRNA (control cells). A drug sensitivity analysis, 3-(4,5)-dimethylthiahiazol (-z-y1)-3,5-di- phenytetrazoliumromide (MTT) assay was performed on Ufd1 knockdown cells and control cells. After treating the cells with HCPT, a caspase-3 and caspase-4 activity assay, flow cytometric analysis and Western blot for detecting phosphorylated c-Jun N-terminal kinase (p-JNK), phosphorylated protein kinases B (p-Akt), P53, ubiquitin, GADD 153 and Grp78/Bip were performed.

RESULTS

According to the MTT assay, the survival rate of knockdown cells was significantly lower than that of the control cells (P < 0.01). Both caspase-3 and caspase-4 activity assay showed higher activation level in Ufd1 knockdown cells than that in the control cells (P < 0.01). A flow cytometric analysis revealed more severe S-phase arrest in the Ufd1 knockdown cells than that in the control cells (P < 0.05). The Western blot showed that increasing the concentration of HCPT resulted in a higher expression level of p-JNK, P53, ubiquitin, GADD 153 and Grp78/Bip in the Ufd1 knockdown cells than that in the control cells.

CONCLUSION

Ufd1 plays a key role in HCPT resistance of SW1116/HCPT and RNAi of Ufd1 can sensitize SW1116/HCPT to the cytotoxic effect of HCPT via strengthening the activation of caspase-3 pathway and disturbing endoplasmic reticulum functions.

Synergistic effects of sonoporation and taurolidin/TRAIL on apoptosis in human fibrosarcoma

Sonodynamic therapy, in combination with ultrasound contrast agents, proved to enhance the uptake of chemotherapeutics in malignant cells. HT1080 fibrosarcoma cells were treated in vitro with a combination of ultrasound SonoVue™-microbubbles and taurolidine (TRD) plus tumor necrosis factor related apoptosis inducing ligand (TRAIL). Apoptosis was measured by TdT-mediated dUTP-biotin nick end labelling (TUNEL) assay and fluorescence activated cell sorting (FACS) analysis. Gene expression was analysed by RNA-microarray. The apoptotic effects of TRD and TRAIL on human fibrosarcoma are enhanced by sonodynamic therapy and additional application of contrast agents, such as SonoVue™ by 25%. A broad change in the expression of genes related to apoptotic pathways is observed when ultrasound and microbubbles act synchronously in combination with the chemotherapeutics (e.g. BIRC3, NFKBIA and TNFAIP3). Some of these genes have already been proven to play a role in programmed cell death in human fibrosarcoma (HSPA1A/HSPA1B, APAF1, PAWR, SOCS2) or were associated with sonication induced apoptosis (CD44). Further studies are needed to explore the options of sonodynamic therapy on soft tissue sarcoma and its molecular mechanisms.

Topoisomerase inhibitors modulate expression of melanocytic antigens and enhance T cell recognition of tumor cells

While there are many obstacles to immune destruction of autologous tumors, there is mounting evidence that tumor antigen recognition does occur. Unfortunately, immune recognition rarely controls clinically significant tumors. Even the most effective immune response will fail if tumors fail to express target antigens. Importantly, reduced tumor antigen expression often results from changes in gene regulation rather than irrevocable loss of genetic information. Such perturbations are often reversible by specific compounds or biological mediators, prompting a search for agents with improved antigen-enhancing properties. Some recent findings have suggested that certain conventional chemotherapeutic agents may have beneficial properties for cancer treatment beyond their direct cytotoxicities against tumor cells. Accordingly, we screened an important subset of these agents, topoisomerase inhibitors, for their effects on antigen levels in tumor cells. Our analyses demonstrate upregulation of antigen expression in a variety of melanoma cell lines and gliomas in response to nanomolar levels of certain specific topoisomerase inhibitors. To demonstrate the ability of CD8+ T cells to recognize tumors, we assayed cytokine secretion in T cells transfected with T cell receptors directed against Melan-A/MART-1 antigen. Three days of daunorubicin treatment resulted in enhanced antigen expression by tumor cells, in turn inducing co-cultured antigen-specific T cells to secrete Interleukin-2 and Interferon-γ. These results demonstrate that specific topoisomerase inhibitors can augment melanoma antigen production, suggesting that a combination of chemotherapy and immunotherapy may be of potential value in the treatment of otherwise insensitive cancers.