Epigenetic regulation of multidrug-resistance and metastasis-related genes in human lung adenocarcinoma cells growing in ectopic or orthotopic organs of nude-mice

We examined whether the organ microenvironment modulates the response of the human lung adenocarcinoma cell line DMS-4C to doxorubicin (DXR). DMS-4C cells were injected intrathoracically (orthotopic) and subcutaneously (ectopic) into nude mice. The mice were given intravenous (i.v.) injections of DXR (8 mg/kg) or saline (control) on days 50 and 58 after implantation, Tumors growing in the subcutis were more sensitive to DXR than tumors growing in the lung. Tumor cells established in culture from lung lesions were initially more resistant to DXR than cells established in culture from subcutaneous (s.c.) tumors. After 14 days in culture, all cells exhibited similar sensitivity to DXR. The expression level of several genes that regulate different steps of metastasis, basic fibroblast growth factor (angiogenesis), type IV collagenase (invasion), epidermal growth factor receptor (growth), and mdr1 (drug resistance), was examined by an in situ mRNA hybridization technique in DMS-4C lesions from the lung and subcutis. Higher mRNA expression for Mdr1, bFGF, and type IV collagenase was found in lung lesions than in s.c. tumors. These results demonstrate that the organ environment influences the expression of several metastasis-related genes in human lung adenocarcinoma cells.

Cell density-dependent regulation of mdr-1 gene expression in murine colon cancer cells

We studied the regulation of mdr-1 and P-glycoprotein in sparse and confluent cultures of murine CT-26 colon carcinoma cells. The expression level of mdr-1 mRNA transcripts (analyzed by Northern blot and in situ hybridization) and P-glycoprotein (analyzed by flow cytometry) inversely correlated with cell density. The modulation of mdr gene expression in sparse and confluent cells was not related to cell division, nutrient depletion, inhibition of protein synthesis, gap junction status, extracellular ATP, or the presence of various extracellular matrixes, but may be related to cell-density and cell-contact mediated changes in phosphatase activity. The confluence-mediated downmodulation of mdr-1 increased the chemosensitivity of the cells to several anticancer drugs commonly associated with an in vitro MDR phenotype by increasing the intracellular accumulation of the drugs. These data may explain some of the discrepancies in results obtained when analyzing mdr gene expression in tumors growing in vivo or in vitro, and why mdi expression in tumors is localized to the periphery of the lesions.

Belief-propagation algorithm and the Ising model on networks with arbitrary distributions of motifs

We generalize the belief-propagation algorithm to sparse random networks with arbitrary distributions of motifs (triangles, loops, etc.). Each vertex in these networks belongs to a given set of motifs (generalization of the configuration model). These networks can be treated as sparse uncorrelated hypergraphs in which hyperedges represent motifs. Here a hypergraph is a generalization of a graph, where a hyperedge can connect any number of vertices. These uncorrelated hypergraphs are treelike (hypertrees), which crucially simplifies the problem and allows us to apply the belief-propagation algorithm to these loopy networks with arbitrary motifs. As natural examples, we consider motifs in the form of finite loops and cliques. We apply the belief-propagation algorithm to the ferromagnetic Ising model with pairwise interactions on the resulting random networks and obtain an exact solution of this model. We find an exact critical temperature of the ferromagnetic phase transition and demonstrate that with increasing the clustering coefficient and the loop size, the critical temperature increases compared to ordinary treelike complex networks. However, weak clustering does not change the critical behavior qualitatively. Our solution also gives the birth point of the giant connected component in these loopy networks.

Demonstration of the metaphylactic use of gamithromycin against bacterial pathogens associated with bovine respiratory disease in a multicentre farm trial

On five commercial cattle rearing sites across Europe, a total of 802 young cattle at high risk of developing bovine respiratory disease (BRD) associated with the bacterial pathogens Mannheimia haemolytica or Pasteurella multocida and/or Mycoplasma bovis were enrolled into a multicentre, controlled field trial. Half were treated with a single dose of gamithromycin at 6 mg/kg bodyweight by subcutaneous injection and half received an injection of a saline placebo as the control. All animals were observed daily for 14 days for signs of BRD as defined by set criteria. The proportion of metaphylactic preventive treatment successes, defined as animals surviving to day 14 without signs of BRD, in the gamithromycin-treated group (86 per cent) was significantly (P=0.0012) higher than in the saline-treated controls (61 per cent). Morbidity among the treated animals was reduced by 64 per cent compared with the controls.

Sorafenib versus cytotoxic chemotherapy for patients with advanced hepatocellular carcinoma: A retrospective, single-institution study

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Background: Prior to the sorafenib era, most of the advanced hepatocellular carcinoma (HCC) patients had to rely only on conventional cytotoxic chemotherapy. But the introduction of sorafenib in 2008 had given HCC patients additional option for their treatment. However, given that sorafenib has been a nonreimbursable drug under the Korea public health system, most of treatment strategy has largely been determined by patients' affordability of the drug rather than by difference in efficacy and toxicity of the two treatments. Therefore, we compared the efficacy and toxicity of the two treatments by observing HCC patients.

Methods: From January 2002 to December 2009, 173 patients with unresectable HCC had been retrospectively analyzed. Among them, 44 (25.4%) had been treated with sorafenib and the remaining had received cytotoxic chemotherapy. We evaluated objective response rate (ORR), progression-free survival (PFS), overall survival (OS), and toxicity profiles.

Results: The median OS of sorafenib group was 23.0 weeks (95% CI, 8.1-37.9) vs. 43.6 weeks (95% CI, 34.0-37.9) for cytotoxic chemotherapy group. The median PFS for sorafenib group was 11.1 weeks (95% CI, 6.5-15.8) versus 12.4 weeks (95% CI, 8.1-16.7) for cytotoxic chemotherapy group. However, the difference in both findings had not been statistically significant (p=0.105 and p=0.496, respectively). ORR and DCR for sorafenib group were 2.3% and 52.3% versus 6.2% and 43.4% for cytotoxic chemotherapy group, respectively. Patients treated with chemotherapy had shown higher frequencies of grade 3 or 4 neutropenia, 19.7%, (vs. 0% for sorafenib). However, the group with sorafenib had reported a higher rate of all grade dermatologic toxicities such as hand-foot skin reaction, rash and pruritus.

Conclusions: Our analysis indicates that efficacy of conventional chemotherapy is not inferior to that of sorafenib. Further research including novel target agent and cytotoxic chemotherapy is needed to improve clinical outcomes for advanced HCC.

No significant financial relationships to disclose.