Factor Analysis for Bicluster Acquisition (FABIA) revealed vincristine-sensitive transcript pattern of canine transmissible venereal tumors.

Chemotherapeutic treatment for Canine transmissible venereal tumor (CTVT) commonly relies on vincristine administration. Since the treatment outcomes can vary among CTVT cases, gaining insight into the tumor cell mechanisms influencing vincristine's potency should render veterinarians novel knowledge to enhance its therapeutic effect. This study aimed to attain such knowledge from a meta-analysis of CTVT mRNA sequencing (mRNA-seq) transcriptome data using Factor Analysis for Bicluster Acquisition (FABIA) biclustering. FABIA biclustering identified 459 genes consistently expressed among mRNA-seq transcription profiling of CTVT samples regressed by vincristine. These genes were also differentially expressed from those of progressive CTVT (FDR ≤ 0.001). Enrichment analysis illustrated the affiliation of these genes with "Antigen presentation" and "Lysosome" GO terms (FDR ≤ 0.05). Several genes in "Lysosome" term involved 5 cell mechanisms-antigen presentation, autophagy, cell-adhesion, lysosomal membrane permeabilization (LMP), and PI3K/mTOR signaling. This study integrated FABIA biclustering in CTVT transcriptome analysis to gain insight into cell mechanisms responsible for vincristine-sensitive characteristics of the tumor, in order to identify new molecular targets augmenting therapeutic effect of vincristine. Interestingly, the analysis indicated LMP targeting by lysosome destabilizing agent-siramesine as the promising vincristine's enhancer for future study. As far as we know, this is the first canine tumor transcriptomic meta-analysis applying FABIA biclustering for the betterment of future CTVT therapy. This study hereby provided an interesting manifestation to acquire such knowledge in other canine neoplasia.

Culture medium and embryo density influence on developmental competence and gene expression of cat embryos.

Morphology and gene expression are the currently preferred methods for assessing the effect of culture medium and density on embryos of several species. To define their effects on domestic cat embryos, groups of 8-10 embryos were cultured in SOF, modified Tyrode's solution or MK-1 medium in a fixed volume (50 µL) and in different volumes (20, 50 and 100 µL). SOF supplemented with different concentrations of glucose (1.5, 3.0 and 6.0 mM) was used to examine the effect of glucose level on embryo development. Real-time reverse transcriptase polymerase chain reaction was used to determine the relative transcripts of BAX, BCL-2 and GLUT-1 genes in blastocysts derived from various concentrations of glucose. SOF and MK-1 supported feline embryo development better than modified Tyrode's solution. Embryos cultured in 20 µL droplets showed decreased development in all three media (P < 0.05). Increasing the glucose concentration in SOF to 6.0 mM adversely affected embryo development and tended to increase the BCL-2 transcript in blastocysts. In conclusion, type of culture medium, embryo density and glucose concentration affected the development of domestic cat embryos. High culture density and glucose concentration negatively affected embryo development. The increase of anti-apoptotic BCL-2 expression found in blastocysts cultured in 6.0 mM glucose may have prevented an increase in the incidence of apoptosis. In the present study, it was clearly demonstrated that differential gene expression occurred in embryos with similar morphology.

The effects of roscovitine on cumulus cell apoptosis and the developmental competence of domestic cat oocytes.

The developmental competence of cat oocytes matured in vitro is relatively poor when compared with that of in vivo oocytes. The study aimed to investigate the effect of roscovitine on the developmental competence of cat Felis catus oocytes matured in vitro. Cumulus-oocyte complexes (COCs) were classified as Grade I and II to III. Groups of COCs were cultured in 0, 12.5, 25, 50, 100, and 200 microM roscovitine for 24h and were either fixed to assess the stages of nuclear maturation (Experiment 1) or additionally matured in vitro for 24h before fixation (Experiment 2). In Experiment 3, cumulus cells from the COCs treated with roscovitine were examined for apoptosis. Experiment 4 examined the developmental competence of cat oocytes after roscovitine treatment and in vitro fertilization in terms of cleavage and morula and blastocyst formation rates. Roscovitine reversibly arrested cat oocytes at an immature stage in a dose-dependent manner. Roscovitine at 12.5 and 25 microM demonstrated less efficiency compared with that of other doses. However, higher doses of roscovitine induced cumulus cell apoptosis and resulted in a high number of degenerated oocytes after in vitro maturation. Roscovitine at 12.5 and 25 microM were therefore used to evaluate their effect on embryo development. Pretreatment with 12.5 and 25 microM roscovitine prior to in vitro maturation decreased the developmental competence of cat oocytes compared with that of non-roscovitine-treated controls. In conclusion, roscovitine reversibly maintained cat oocytes at the germinal vesicle stage without detrimental effect on nuclear maturation. However, it negatively affected cumulus cell viability and developmental competence.