# The Role of the Endocannabinoid System in Oncology and the Potential Use of Cannabis Derivatives for Cancer Management in Companion Animals

## TL;DR

This review explores how the endocannabinoid system and cannabis derivatives may help treat cancer in pets, offering new therapeutic options alongside traditional chemotherapy.

## Contribution

The paper provides a comprehensive overview of the endocannabinoid system's role in cancer and its potential as a therapeutic target in veterinary oncology.

## Key findings

- Endocannabinoid system receptors and enzymes are often altered in tumors, possibly affecting cancer progression.
- Cannabinoids can modulate cell signaling, induce cell death, and inhibit cancer growth and metastasis.
- Cannabinoids show synergistic effects with traditional chemotherapy drugs, improving treatment outcomes.

## Abstract

Companion animals are more and more becoming considered family members, and their owners wish to offer them the same level of cure and care expected for a human being. The long life expectancy of dogs and cats is associated with new challenges: veterinary medicine must be prepared to diagnose and treat neoplastic pathology with the same high-standard procedures that are currently used in human medicine. Chemotherapies aim to prolong as long as possible the life of companion animals affected by cancer, but several side effects can be experienced. Thus, an increasing interest in alternative and complementary treatments has arisen in the last years. Among a wide array, cannabinoids seem to be a promising tool to be included in therapeutic protocols since their administration could assist traditional chemotherapeutic agents, promoting a more successful antineoplastic effect, prolonging the prognosis, and contributing to patient well-being thanks to pain relief. According to all the aforementioned factors, the present review aims to summarize how the endocannabinoid system and phytocannabinoids interact in the complex process of carcinogenesis, exploring current therapeutical applications and future perspectives in veterinary oncology.

The last decades of research have shown that the endocannabinoid system may be a promising therapeutic target for the pharmacological treatment of cancer in human medicine and possibly in veterinary medicine as well. Compared with the original cells, the expression of gene encoding for receptors and enzymes belonging to the endocannabinoid system has been found to be altered in several tumor types; it has been hypothesized that this aberrant expression may be related to the course of the neoplasm as well as to the patient’s prognosis. Several studies, conducted both in vitro and in vivo, suggest that both endo- and phytocannabinoids can modulate signaling pathways, controlling cell proliferation and survival. In the complex process of carcinogenesis, cannabinoids seem to intervene at different levels by stimulating cell death, inhibiting the processes of angiogenesis and metastasis, and regulating antitumor immunity. Although the molecular mechanisms by which cannabinoids act are not always clear and defined, their synergistic activity with the most used antineoplastic drugs in clinical oncology is showing promising results, thus providing veterinary medicine with alternative therapeutic targets in disease control. This review aims to summarize current knowledge on the potential role of the endocannabinoid system and exogenous cannabinoids in oncology, with specific reference to the molecular mechanisms by which cannabinoids may exert antitumor activity. Additionally, it explores the potential synergy between cannabinoids and conventional anticancer drugs and considers their application in veterinary oncology.