5-Lipoxygenase expression in benign and malignant canine prostate tissues*

Comparative Pathobiology of Canine and Human Prostate Cancer: State of the Art and Future Directions

First described in 1817, prostate cancer is considered a complex neoplastic entity, and one of the main causes of death in men in the western world. In dogs, prostatic carcinoma (PC) exhibits undifferentiated morphology with different phenotypes, is hormonally independent of aggressive character, and has high rates of metastasis to different organs. Although in humans, the risk factors for tumor development are known, in dogs, this scenario is still unclear, especially regarding castration. Therefore, with the advent of molecular biology, studies were and are carried out with the aim of identifying the main molecular mechanisms and signaling pathways involved in the carcinogenesis and progression of canine PC, aiming to identify potential biomarkers for diagnosis, prognosis, and targeted treatment. However, there are extensive gaps to be filled, especially when considering the dog as experimental model for the study of this neoplasm in humans. Thus, due to the complexity of the subject, the objective of this review is to present the main pathobiological aspects of canine PC from a comparative point of view to the same neoplasm in the human species, addressing the historical context and current understanding in the scientific field.

The bioactive alkaloids identified from Cortex Phellodendri ameliorate benign prostatic hyperplasia via LOX-5/COX-2 pathways

BACKGROUND

The bioactive alkaloids identified from Cortex Phellodendri (CP) were highly effective in treating rats with benign prostatic hyperplasia (BPH). Specifically, lipoxygenase-5 (LOX-5) and cyclooxygenase-2 (COX-2) were identified as two primary targets for alleviating inflammation in BPH rats. However, it remains unknown whether the alkaloid components in CP can interact with the two target proteins.

PURPOSE

To further identify bioactive alkaloids targeting LOX/COX pathways.

METHODS

An affinity-ultrafiltration mass spectrometry approach was employed to screen dual-target LOX-5/COX-2 ligands from alkaloid extract. The structures of bioactive alkaloids were characterized by high-resolution Fourier transform ion cyclotron resonance mass spectrometry. To understand the molecular mechanisms underlying the effects of bioactive alkaloids, the expression levels of LOX-5 and COX-2 in BPH model rats were investigated at both protein and mRNA levels. The LOX-5/COX-2 enzymes activity experiments and molecular docking analysis were performed to fully evaluate the interactions between bioactive alkaloids and LOX-5/COX-2.

RESULTS

After comprehensive analysis, the results showed that bioactive alkaloids could suppress the expression of LOX-5 and COX-2 simultaneously to exert an anti-inflammatory effect on the progression of BPH. In addition, the screened protoberberine, demethyleneberberine was found to exhibit prominent inhibitory activities against both LOX-5 and COX-2 enzymes, palmatine and berberine with moderate inhibitory activities. Molecular docking analysis confirmed that demethyleneberberine could interact well with LOX-5/COX-2.

CONCLUSION

This study is the first to explore the inhibitory effects of bioactive alkaloids from CP on LOX-5 and COX-2 activities in BPH rats. Our findings demonstrate that the bioactive alkaloids from CP can ameliorate BPH via dual LOX-5/COX-2 pathways, which serves as an efficient approach for the discovery of novel drug leads from natural products with reduced side effects.

Comparative Cancer Cell Signaling in Muscle-Invasive Urothelial Carcinoma of the Bladder in Dogs and Humans

Muscle-invasive urothelial carcinoma (MIUC) is the most common type of bladder malignancy in humans, but also in dogs that represent a naturally occurring model for this disease. Dogs are immunocompetent animals that share risk factors, pathophysiological features, clinical signs and response to chemotherapeutics with human cancer patients. This review summarizes the fundamental pathways for canine MIUC initiation, progression, and metastasis, emerging therapeutic targets and mechanisms of drug resistance, and proposes new opportunities for potential prognostic and diagnostic biomarkers and therapeutics. Identifying similarities and differences between cancer signaling in dogs and humans is of utmost importance for the efficient translation of in vitro research to successful clinical trials for both species.

Lipoxygenase-5 Expression in Canine Urinary Bladder: Normal Urothelium, Cystitis and Transitional Cell Carcinoma

Transitional cell carcinoma (TCC) is the most common canine urinary tract tumour and mimics human invasive TCC. Human TCCs overexpress lipoxygenase (LOX)-5 and the use of target inhibitors has proven effective in inhibiting neoplastic growth. In this study, we investigated the immunohistochemical expression of LOX-5 in normal canine urinary bladder, cystitis and TCC. The comparative expression of LOX-5, cyclo-oxygenase (COX)-1 and COX-2 among the three tissue groups was also examined. Biopsy samples from cases of cystitis and TCC were reviewed from 2012 to 2016; samples of histologically normal bladder were used as controls. Dogs were excluded if they had received glucocorticoids, non-steroidal anti-inflammatory drugs (NSAIDs) and/or chemotherapy prior to tissue collection. LOX-5 was expressed in 95% of TCCs, 23% of cases of cystitis and 10% of controls. LOX-5 and COX-2 immunohistochemistry scores were significantly (P <0.01) higher in TCCs versus cystitis and normal bladders. Results of this study support the rationale for further investigation of the use of NSAIDs with dual anti COX-2 and LOX-5 effect for the treatment of canine TCC.