MicroRNA expression patterns in canine mammary cancer show significant differences between metastatic and non-metastatic tumours

Background

MicroRNAs may act as oncogenes or tumour suppressor genes, which make these small molecules potential diagnostic/prognostic factors and targets for anticancer therapies. Several common oncogenic microRNAs have been found for canine mammary cancer and human breast cancer. On account of this, large-scale profiling of microRNA expression in canine mammary cancer seems to be important for both dogs and humans.

Methods

Expression profiles of 317 microRNAs in 146 canine mammary tumours of different histological type, malignancy grade and clinical history (presence/absence of metastases) and in 25 control samples were evaluated. The profiling was performed using microarrays. Significance Analysis of Microarrays test was applied in the analysis of microarray data (both unsupervised and supervised data analyses were performed). Validation of the obtained results was performed using real-time qPCR. Subsequently, predicted targets for the microRNAs were searched for in miRBase.

Results

Results of the unsupervised analysis indicate that the primary factor separating the samples is the metastasis status. Predicted targets for microRNAs differentially expressed in the metastatic vs. non-metastatic group are mostly engaged in cell cycle regulation, cell differentiation and DNA-damage repair. On the other hand, the supervised analysis reveals clusters of differentially expressed microRNAs unique for the tumour type, malignancy grade and metastasis factor.

Conclusions

The most significant difference in microRNA expression was observed between the metastatic and non-metastatic group, which suggests a more important role of microRNAs in the metastasis process than in the malignant transformation. Moreover, the differentially expressed microRNAs constitute potential metastasis markers. However, validation of cfa-miR-144, cfa-miR-32 and cfa-miR-374a levels in blood samples did not follow changes observed in the non-metastatic and metastatic tumours.

Electronic supplementary material

The online version of this article (10.1186/s12885-017-3751-1) contains supplementary material, which is available to authorized users.

Interferon lambda 2 promotes mammary tumor metastasis via angiogenesis extension and stimulation of cancer cell migration

Myeloid-derived suppressor cells (MDSCs) support tumor development by stimulation of angiogenesis and immune response inhibition. In our previous study, we showed that interferon lambda 2 (IFN-λ2), secreted by MDSCs, enhances production of pro-angiogenic factors by cancer cells via phosphorylation of STAT3 and therefore promotes blood vessels formation. In the present study IFN-λ2 level was evaluated by ELISA in serum of tumor-bearing mice, whereas its expression in MDSCs isolated from the lungs with metastatic tumors and normal lungs was assessed by qPCR. The effect of IFN-λ2 on mouse mammary cancer cells motility was tested in Boyden chamber migration assay. In order to evaluate its pro-angiogenic function we performed in vitro tubule formation assay and in ovo angiogenesis assay on chicken embryo chorioallantoic membrane (CAM). Moreover, in order to design small molecule inhibitors of IFN-λ2 and its receptor we performed molecular modeling followed by the identification of potential natural inhibitors. Then, we examined their ability to inhibit angiogenesis in vitro. Our results showed that IFN-λ2 predisposed mouse mammary cancer cells to migration in vitro. It also enhanced angiogenesis induced by mouse mammary cancer cells in vitro and in ovo. For the first time we selected potential IFN-λ2 inhibitors and we validated that they were capable to abolish pro-angiogenic effect of IFN-λ2, similarly to blocking antibodies. Therefore, IFN-λ2 and its receptor may become targets of anti-cancer therapy, but their mechanism of action requires further investigation.

[The significance of disinfection in preventing nosocomial infections]

Comparable analyses of the frequency of isolation at aerobic bacteria from clinical test material resp. from cockroaches (body surface and faecal contents) henced the epidemiological relationships which underline the necessity of complex and effective measures of disinfection on the prophylaxis of nosocomial infections.

[Behavior of staphylococci of the nasal cavity in subjects exposed to hyperbaric oxygen]

A careful qualitative and quantitative study revealed a significant decrease in bacterial, and especially staphylococcal, cultures from nasal swabs 24 hr after exposure to oxygen at 2.5 atm for 30', followed by a gradual return to initial values after a further four days. It is felt that this picture was ascribable to the influence of hyperbaric O2 on the microorganisms and their metabolism, and on the body's defence mechanisms.

[Changes in the pharyngeal bacterial flora during hyperbaric oxygenation]

Qualitative and quantitative bacteriological tests of throat smears were carried out on the following three groups of patients: 1) Patients exposed to several 90-minute sequences of oxygen hyperbaria, at a height of 2.2 ata O2, at intervals of 2 to 3 days. 2) Patients exposed to a single 30-minute dose of oxygen hyperbaria at a height of 2.5 ata O2/the oxygen test. 3) Patients who had never been exposed to oxygen hyperbaria. Several hundred bacterials strains of the Streptococcus, Staphylococcus, Klebsiella and Nocardia genus were isolated from the material collected from the tested patients over intervals of a few days. The collected samples were when subjected to a detailed bacteriological analysis. At the same time bacteriological tests were performed at intervals on the hyperbaric atmosphere of the therapeutic pressure chamber, the walls of the chamber, and the masks used by the patients during the administration of hyperbaric oxygen. A certain degree of qualitative and quantitative changes (number reduction of bacterial strains) was observed. The authors attribute these results to the influence of hyperbaric oxygenation both on the microorganisms, as well as on a given patient's reactivity.

Study on the possibility of adopting a complex method in Blattella germanica (L.) control on board ships

Campaings to control the German cockroach, Blattela germanica, were conducted at 14-day intervals over a period of 5.5 months on two merchant vessels of similar size and type. On one ship only the chemical "Gertoks", carbamate insecticide containing 1% propoxur was applied, and on the second ship two preparations simultaneously, a chemical and a biological--"Biotrol 25 W" containing Bacillus thuringiensis. - In order to assess the success of the control, the extent of infestation in the accomodation was determined immediately before and 24 h after the spraying. - The susceptibility of the cockroaches caught on the ships, to the two preparations applied, was also determined. It was found that "Gertoks" was an efficient preparation, the biopreparation "Biotrol 25 W" being less efficient. - A certain increase in resistance of the cockroaches to both preparations, was noted. - The above observations indicate that a considerable drop in numbers of population of cockroaches can be achieved if the ship's crew carry out systematic thorough spraying of ships quarters infested by cockroaches, with Gertoks". They also confirm previous suggestions that complex method in B. germanica control on board ships is possible, using chemical and biological preparations containing Bac. thuringiensis spores simultaneously.

Influence of oxygen hyperbaria on the activity of complement in human's sera

Studies on the effect of hyperbaric oxygenation on serum complement activity were carried out in 133 young men aged 20--22 years, quartered and given the same board. For this purpose the 50% hemolysis method was used, the determinations being made prior to the hyperbaric exposure and 72 hours, 5 days and 10 days thereafter. The exposure took place in a pressure chamber, where the respective groups studied underwent a 60 min oxygenation at normal pressure, highpressure oxygenation at 2.8 atmospheres and the effect of the air at the same pressure. For proper assessment of the results the studies were also performed in candidates for divers and frogmen, in trained divers and frogmen and in control, non-diving subjects in whom only complement activity determinations were made. It was found, that in the subjects who were never previously exposed to the effect of hyperbaric conditions, a rise in the complement activity occurred subsequently to the exposure to high-pressure oxygenation at 2.8 atmospheres; the complement level returned to normal limits within 10 days.

Studies of the infection of the cockroaches (Blattella germanica[L.]) with Bac. thuringensis

The results of an experimental infection of the cockroaches Blattella germanica (L.) with some trade preparations containing Bac. thuringensis spores are presented. Biological studies supported by bacteriological and histological examinations of the excised intestines of the above insects have shown that the microorganisms studied are pathogenic for the cockroaches. This effect might be eventually applied as a biological method of eradication of the cockroaches in such environments, where chemical preparations can not be used or this disinfestation method would be complementary to the other method of disinfestation.