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Treatment strategies for metastatic renal cell carcinoma (RCC) have been limited due to chemotherapy and radiotherapy resistance. The development of targeted drugs has now opened novel therapeutic options. In the present study, anti-tumoral properties of the histone deacetylase inhibitor valproic acid (VPA) were tested in vitro and in vivo on pre-clinical RCC models. RCC cell lines Caki-1, KTC-26 or A498 were treated with various concentrations of VPA to evaluate tumour cell adhesion to vascular endothelial cells or to immobilized extracellular matrix proteins. In vivo tumour growth was conducted in subcutaneous xenograft mouse models. VPA was also combined with low dosed interferon-alpha (IFN-alpha) and the efficacy of the combination therapy, as opposed to VPA monotherapy, was compared. VPA significantly and dose-dependently prevented tumour cell attachment to endothelium or matrix proteins, accompanied by elevated histones H3 and H4 acetylation. VPA altered integrin-alpha and -beta subtype expression, in particular alpha(3), alpha(5) and beta(3), and blocked integrin-dependent signalling. In vivo, VPA significantly inhibited the growth of Caki-1 in subcutaneous xenografts with the 200 mg/kg being superior to the 400 mg/kg dosing schedule. VPA-IFN-alpha combination markedly enhanced the effects of VPA on RCC adhesion, and in vivo tumour growth was further reduced by the 400 mg/kg but not by the 200 mg/kg VPA dosing schedule. VPA profoundly blocked the interaction of RCC cells with endothelium and extracellular matrix and reduced tumour growth in vivo. Therefore, VPA should be considered an attractive candidate for clinical trials.

Isolated human hepatocytes are of great value in investigating cell transplantation, liver physiology, pathology, and drug metabolism. Though hepatocytes possess a tremendous proliferative capacity in vivo, their ability to grow in culture is severely limited. We postulated that repeated medium change, common to most in vitro systems, may prevent long-term maintenance of hepato-specific functions and growth capacity. To verify our hypotheses we compared the DNA synthesis and differentiation status of isolated human hepatocytes, cultured in medium which was renewed every day or was not changed for 3 weeks ('autocrine' setting). Daily medium change led to rapid hepatocellular de-differentiation without any signs of DNA replication. In contrast, the autocrine setting allowed hepatocytes to become highly differentiated, demonstrated by an elevated ASGPr expression level, and increased albumin and fibrinogen synthesis and release. Cytokeratin 18 filaments were stably expressed, whereas cytokeratin 19 remained undetectable. Hepatocytes growing in an autocrine fashion were activated in the presence of hepatocyte growth factor (HGF), evidenced by c-Met phosphorylation. However, HGF response was not achieved when the culture medium was renewed daily. Furthermore, the autocrine setting evoked a late but strong interleukin 6 release into the culture supernatant, reaching maximum values after a 10-day cultivation period, and intense BrdU incorporation after a further 5-day period. Our data suggest that preservation of the same medium creates environmental conditions which allow hepatocytes to control their differentiation status and DNA synthesis in an autocrine fashion. Further studies are necessary to identify the key mediators involved in autocrine communication and to design the optimal culture configuration for clinical application.

In vitro models have suggested that chemokines of the CXC family may regulate prostate cancer cell proliferation and dissemination. In this study, we evaluated the expression of CXC receptors (CXCRs) and CXC ligands (CXCLs) in prostate cancer tissue. CXCL1-16 and CXCR1-6 mRNA were identified by RT-PCR in prostate tumors and adjacent normal tissue specimens. Samples were obtained from 49 patients undergoing radical prostatectomy. mRNA expression was semiquantitatively scored and correlated with pretreatment prostate-specific antigen (PSA), the Gleason score, early patient follow-up and Kattan postoperative prediction. CXCL12 mRNA expression level was significantly enhanced, whereas CXCL13 was reduced in prostate tumor compared to adjacent 'normal' tissue. No differences were observed in the CXCR4 mRNA level; however, both CXCR3 and CXCR5 were reduced significantly in the tumor tissue. The difference in CXCL12 and CXCL13 (CXCLΔ) correlated significantly with PSA levels and the Gleason score. Furthermore, CXCLΔ correlated significantly with the Kattan postoperative nomogram. Tumor progression was observed in patients with high CXCLΔ values, but not in those with low values, in early follow-up. The development and progression of prostate cancer was accompanied by alterations of CXC chemokine expression, in particular CXCL12, CXCL13, CXCR3 and CXCR5. Novel treatment options could therefore be targeted at one or several of these proteins. The practicability of CXC chemokines as potential prognostic markers requires further study.

Histone deacetylase (HDAC) inhibitors belong to a promising class of antineoplastic agents which affect tumor growth, differentiation and invasion. The effects of the HDAC inhibitor valproic acid (VPA) were tested in vitro on preclinical colon and pancreatic cancer models. Human colon adenocarcinoma HT-29 and pancreatic carcinoma DanG cells were treated with 1 mM VPA for different time periods during cell proliferation MTT assays, and to evaluate the tumor cell adhesion to endothelial cell monolayers. Alterations of beta1 integrin subunits alpha1-6) were analyzed by flow cytometry and RT-PCR. VPA significantly caused growth arrest in tumor cells and prevented tumor cell attachment to the endothelium. HT-29 cell adhesion was blocked to a higher extent than the adhesion of DanG cells. VPA modified membranous integrin beta1 expression, quantity and quality (up- or down-regulation) which depended on the tumor type investigated. Furthermore, VPA diminished integrin coding mRNA in HT-29 but not in DanG cells. We conclude that VPA shifts the integrin beta1 subunit balance from a 'pathological' towards a 'physiological' expression pattern leading to reduced tumor growth and invasion. Further study is required to elucidate the molecular background of the post-transcriptional modifications of VPA in order to exploit the potential of this agent in the treatment of colon and pancreatic cancer.

Isolated human hepatocytes are of great value in investigating cell transplantation, liver physiology, pathology, and drug metabolism. Though hepatocytes possess a tremendous proliferative capacity in vivo, their ability to grow in culture is severely limited. We postulated that repeated medium change, common to most in vitro systems, may prevent long-term maintenance of hepato-specific functions and growth capacity. To verify our hypotheses we compared the DNA synthesis and differentiation status of isolated human hepatocytes, cultured in medium which was renewed every day or was not changed for 3 weeks ('autocrine' setting). Daily medium change led to rapid hepatocellular de-differentiation without any signs of DNA replication. In contrast, the autocrine setting allowed hepatocytes to become highly differentiated, demonstrated by an elevated ASGPr expression level, and increased albumin and fibrinogen synthesis and release. Cytokeratin 18 filaments were stably expressed, whereas cytokeratin 19 remained undetectable. Hepatocytes growing in an autocrine fashion were activated in the presence of hepatocyte growth factor (HGF), evidenced by c-Met phosphorylation. However, HGF response was not achieved when the culture medium was renewed daily. Furthermore, the autocrine setting evoked a late but strong interleukin 6 release into the culture supernatant, reaching maximum values after a 10-day cultivation period, and intense BrdU incorporation after a further 5-day period. Our data suggest that preservation of the same medium creates environmental conditions which allow hepatocytes to control their differentiation status and DNA synthesis in an autocrine fashion. Further studies are necessary to identify the key mediators involved in autocrine communication and to design the optimal culture configuration for clinical application.

Increases in pro-inflammatory cytokine levels and tissue-infiltrating leukocytes have been closely linked to increased systemic and local inflammation, which result in organ injury. Previously, we demonstrated the beneficial and hepatoprotective anti-inflammatory effects of acute ethanol (EtOH) ingestion in an in vivo model of acute inflammation. Due to its undesirable side-effects, however, EtOH does not represent a therapeutic option for treatment of acute inflammation. Therefore, in this study, we compared the effects of acute EtOH exposure with ethyl pyruvate (EtP) as an alternative anti-inflammatory drug in an in vitro model of hepatic and pulmonary inflammation. Human hepatocellular carcinoma cells Huh7 and alveolar epithelial cells A549 were stimulated with either interleukin (IL) IL-1β (1 ng/ml, 24 h) or tumor necrosis factor (TNF) (10 ng/ml, 4 h), and then treated with EtP (2.5-10 mM), sodium pyruvate (NaP, 10 mM) or EtOH (85-170 mM) for 1 h. IL-6 or IL-8 release from Huh7 or A549 cells, respectively, was measured by an enzyme‑linked immunosorbent assay. Neutrophil adhesion to cell monolayers and CD54 expression were also analyzed. Bcl-2 and Bax gene expression was determined by RT-qPCR, and western blot analysis was performed to determine the mechanisms involved. Treating A549 cells with either EtOH or EtP significantly reduced the IL-1β- or TNF‑induced IL-8 release, whereas treating Huh7 cells did not significantly alter IL-6 release. Similarly, neutrophil adhesion to stimulated A549 cells was significantly reduced by EtOH or EtP, whereas for Huh7 cells the tendency for reduced neutrophil adhesion rates by EtOH or EtP was not significant. CD54 expression was noticeably reduced in A549 cells, but this was not the case in Huh7 cells after treatment. The Bax/Bcl-2 ratio was dose‑dependently decreased by EtOH and by high-dose EtP in A549 cells, indicating a reduction in apoptosis, whereas this effect was not observed in Huh7 cells. The underlying mechanisms involve reduced phosphorylation of Akt and nuclear factor-κB (NF-κB) p65. We noted that as with EtP, EtOH reduced the inflammatory response in lung epithelial cells under acute inflammatory conditions. However, due to the low impact which EtP and EtOH had on the hepatocellular cells, our data suggest that both substances exerted different effects depending on the cellular entity. The possible underlying mechanisms involved the downregulation of Akt and the transcription factor NF-κB, but further research on this subject is required.

Background Single drug use has not achieved satisfactory results in the treatment of prostate cancer, despite application of increasingly widespread targeted therapeutics. In the present study, the combined impact of the mammalian target of rapamycin (mTOR)-inhibitor RAD001, the dual EGFr and VGEFr tyrosine kinase inhibitor AEE788 and the histone deacetylase (HDAC)-inhibitor valproic acid (VPA) on prostate cancer growth and adhesion in vitro was investigated. Methods PC-3, DU-145 and LNCaP cells were treated with RAD001, AEE788 or VPA or with a RAD-AEE-VPA combination. Tumor cell growth, cell cycle progression and cell cycle regulating proteins were then investigated by MTT-assay, flow cytometry and western blotting, respectively. Furthermore, tumor cell adhesion to vascular endothelium or to immobilized extracellular matrix proteins as well as migratory properties of the cells was evaluated, and integrin α and β subtypes were analyzed. Finally, effects of drug treatment on cell signaling pathways were determined. Results All drugs, separately applied, reduced tumor cell adhesion, migration and growth. A much stronger anti-cancer effect was evoked by the triple drug combination. Particularly, cdk1, 2 and 4 and cyclin B were reduced, whereas p27 was elevated. In addition, simultaneous application of RAD001, AEE788 and VPA altered the membranous, cytoplasmic and gene expression pattern of various integrin α and β subtypes, reduced integrin-linked kinase (ILK) and deactivated focal adhesion kinase (FAK). Signaling analysis revealed that EGFr and the downstream target Akt, as well as p70S6k was distinctly modified in the presence of the drug combination. Conclusions Simultaneous targeting of several key proteins in prostate cancer cells provides an advantage over targeting a single pathway. Since strong anti-tumor properties became evident with respect to cell growth and adhesion dynamics, the triple drug combination might provide progress in the treatment of advanced prostate cancer.

A disintegrin and metalloproteinase 17 (ADAM17) is a metalloprotease that is overexpressed in many cancer types, including renal cancers. However, the regulatory mechanisms of ADAM17 in cancer development and progression are poorly understood. In the present work, we provide evidence using overexpression and inhibition of microRNA 145 (miR-145) that miR-145 negatively regulates ADAM17 expression. Furthermore, we show that ADAM17 negatively regulates miR-145 through tumor necrosis factor-α, resulting in a reciprocal negative feedback loop. In this study, the expression of ADAM17 and miR-145 correlated negatively in renal cancer tumor tissues and cell lines, suggesting an important regulatory mechanism. Additionally, we showed that the regulation of ADAM17 is partly involved in the effects of miR-145 on proliferation and migration, whereas no involvement in chemosensitivity was observed. Importantly, in the healthy kidney, miR-145 was detected in different cell types including tubular cells, which are considered the origin of renal cancer. In renal cancer cell lines, miR-145 expression was strongly suppressed by methylation. In summary, miR-145 is downregulated in renal cancer patients, which leads to the up-regulation of ADAM17 in renal cancer. Importantly, miR-145 and ADAM17 are regulated in a reciprocal negative feedback loop.