Electrochemotherapy induces tumor regression and decreases the proliferative index in canine cutaneous squamous cell carcinoma

Surgical management of squamous cell carcinoma of the canine male external genitalia: 15 cases (1994-2020)

Fifteen male dogs with squamous cell carcinoma of the external genitalia were admitted for further investigation and surgical management between 1994 and 2020. The dogs belonged to various breeds. Thirteen dogs were intact and two were castrated with a median age of 8 years and a median weight of 28 kg. Seven dogs were white-coated and eight nonwhite coated. Scrotal ablation and orchiectomy were performed in four dogs, partial penile amputation in two, partial penile amputation plus partial preputial ablation in one, penile amputation, and scrotal urethrostomy in seven, and local preputial excision in one dog. Postoperative complications included hemorrhage in 10 dogs, bruising at the urethrostomy site in seven, and urethrostomy dehiscence in one dog. Tumor recurrence was recorded in six dogs. Dogs with poorly differentiated tumors that had tumor recurrence had shorter survival and worse prognosis compared to those with well and moderately differentiated tumors. The mean survival time was 48.132 months. After a median follow-up of 23 months (range: 8 to 72 months), eight dogs were alive, five were euthanized and two dogs died from unrelated causes. Surgical excision seems to be a treatment option for dogs with squamous cell carcinoma of the external genitalia.

Electrochemotherapy in dogs and cats-A review

Electrochemotherapy (ECT) is a treatment modality that combines the electroporation of cell membranes with chemotherapy to facilitate the transport of non-permeant molecules into cells. Several canine and feline studies have shown promising results, suggesting that ECT can be a valid adjuvant or alternative treatment option for some tumours. The objective of this paper is to provide a bibliographic review of the principles and applications of ECT in veterinary medicine and to compare to its use in human medicine.

Characterization of the skin microbiome in normal and cutaneous squamous cell carcinoma affected cats and dogs

Human cutaneous squamous cell carcinomas (SCCs) and actinic keratoses (AK) display microbial dysbiosis with an enrichment of staphylococcal species, which have been implicated in AK and SCC progression. SCCs are common in both felines and canines and are often diagnosed at late stages leading to high disease morbidity and mortality rates. Although recent studies support the involvement of the skin microbiome in AK and SCC progression in humans, there is no knowledge of this in companion animals. Here, we provide microbiome data for SCC in cats and dogs using culture-independent molecular profiling and show a significant decrease in microbial alpha diversity on SCC lesions compared to normal skin (P ≤ 0.05). Similar to human skin cancer, SCC samples had an elevated abundance of staphylococci relative to normal skin-50% (6/12) had >50% staphylococci, as did 16% (4/25) of perilesional samples. Analysis of Staphylococcus at the species level revealed an enrichment of the pathogenic species Staphylococcus felis in cat SCC samples, a higher prevalence of Staphylococcus pseudintermedius in dogs, and a higher abundance of Staphylococcus aureus compared to normal skin in both companion animals. Additionally, a comparison of previously published human SCC and perilesional samples against the present pet samples revealed that Staphylococcus was the most prevalent genera across human and companion animals for both sample types. Similarities between the microbial profile of human and cat/dog SCC lesions should facilitate future skin cancer research.

IMPORTANCE

The progression of precancerous actinic keratosis lesions (AK) to cutaneous squamous cell carcinoma (SCC) is poorly understood in humans and companion animals, despite causing a significant burden of disease. Recent studies have revealed that the microbiota may play a significant role in disease progression. Staphylococcus aureus has been found in high abundance on AK and SCC lesions, where it secretes DNA-damaging toxins, which could potentiate tumorigenesis. Currently, a suitable animal model to investigate this relationship is lacking. Thus, we examined the microbiome of cutaneous SCC in pets, revealing similarities to humans, with increased staphylococci and reduced commensals on SCC lesions and peri-lesional skin compared to normal skin. Two genera that were in abundance in SCC samples have also been found in human oral SCC lesions. These findings suggest the potential suitability of pets as a model for studying microbiome-related skin cancer progression.

Cell proliferation and apoptosis in canine oral papillomatosis

This study was aimed at the evaluation of cell proliferation, p53 level and apoptotic index by immunohistochemical methods in canine oral papillomatosis. The study material comprised of tumor tissue samples taken from six dogs being admitted to the Pathology Department of Faculty of Veterinary Medicine, Kafkas University, Kars, Türkiye. Choice of immunohistochemical staining was avidin-biotin peroxidase method. Cases of canine oral papillomatosis, determined to have been caused by canine papillomavirus-1, were found to have a rather high cell proliferation index. Furthermore, all cases were immunohisto-chemically demonstrated to carry a mutant p53 gene. Despite the mutation of p53 gene, the shift in the Bax/Bcl-2 ratio of dogs diagnosed with tumor was in favor of the pro-apoptotic Bax gene. The apoptotic mechanism was determined to occur through both the caspase-dependent and caspase-independent pathways. While the lesions occupied the entire oral cavity in some cases, histopathologically, malignant transformation was not detected in any of the six cases.

Essential oil of lemon myrtle (Backhousia citriodora) induces S-phase cell cycle arrest and apoptosis in HepG2 cells

ETHNOPHARMACOLOGICAL RELEVANCE

Lemon myrtle (Backhousia citriodora F.Muell.) leaves, whether fresh or dried, are used traditionally in folk medicine to treat wounds, cancers, skin infections, and other infectious conditions. However, the targets and mechanisms related to anti-cancer effect of lemon myrtle are unavailable. In our study, we found that the essential oil of lemon myrtle (LMEO) showed anti-cancer activity in vitro, and we initially explored its mechanism of action.

MATERIALS AND METHODS

We analyzed the chemical compositions of LMEO by GC-MS. We tested the cytotoxicity of LMEO on various cancer cell lines using the MTT assay. Network pharmacology was used also to analyze the targets of LMEO. Moreover, the mechanisms of LMEO were investigated through scratch assay, flow cytometry analysis, and western blot in the HepG2 liver cancer cell line.

RESULTS

LMEO showed cytotoxicity on various cancer cell lines with values of IC₅₀ 40.90 ± 2.23 (liver cancer HepG2 cell line), 58.60 ± 6.76 (human neuroblastoma SH-SY5Y cell line), 68.91 ± 4.62 (human colon cancer HT-29 cell line) and 57.57 ± 7.61 μg/mL (human non-small cell lung cancer A549 cell line), respectively. The major cytotoxic chemical constituent in LMEO was identified as citrals, which accounted for 74.9% of the content. Network pharmacological analysis suggested that apurinic/apyrimidinic endodeoxyribonuclease 1 (APEX1), androgen receptor (AR), cyclin-dependent kinases 1 (CDK1), nuclear factor erythroid 2-related factor 2 (Nrf-2), fatty acid synthase (FASN), epithelial growth factor receptor (EGFR), estrogen receptor 1 (ERα) and cyclin-dependent kinases 4 (CDK4) are potential cytotoxic targets of LMEO. These targets are closely related to cell migration, cycle and apoptosis. Notley, the p53 protein had the highest confidence to co-associate with the eight common targets, which was further confirmed by scratch assay, flow cytometry analysis, and western blot in the HepG2 liver cancer cell line. LMEO significantly inhibited the migration of HepG2 cells in time-dependent and dose-dependent manner. Moreover, LMEO caused a S-phase blocking on HepG2 cells and promoted apoptosis in the meanwhile. Western blot results indicated that p53 protein, Cyclin A2 and Bax proteins were up-regulated, while Cyclin E1 and Bcl-2 proteins were down-regulated.

CONCLUSION

LMEO showed cytotoxicity in various cancer cell lines in vitro. Pharmacological networks showed LMEO to have multi-component and multi-targeting effects that are related to inhibit migration of HepG2 cells, and affect cell cycle S-phase arrest and apoptosis through modulation of p53 protein.

Canine squamous cell carcinoma: Electrochemotherapy association with surgery and correlation with overall survival

Squamous cell carcinoma (SCC) is an important malignancy in dogs, due to its incidence and clinical presentation, which can be of locally aggressive single or multiple lesions with a metastatic potential. The objective of this investigation was to evaluate SCC response to treatment, anatomopathological and immunohistochemical characteristics, disease-free interval and overall survival time. 54 dogs with histopathologically diagnosed SCC were included in this study. Their mean age was 9.16 years with a range of 1-14 years. Of the 54 animals in the study, 34 (65.4%) had white skin and white fur coats. There was a significant correlation between fur coat colour and the development of tumours in areas of sun exposure (p = .001). Animals with tumours in areas of the body exposed to the sun had longer overall survival time than animals with tumours in areas not associated with sun exposure (p = .001). Surgery combined with electrochemotherapy (ECT) yielded a survival rate 32% higher than using a surgical approach alone (HR = 0.32, p = .038, IC = 0.11-0.94). ECT, with or without surgery, had an objective response rate of 90.9%. Local lymph node and/or distant site metastasis at diagnosis, or at some point during follow-up, occurred in 34.6% (18/52) of animals. Animals with tumours in sun exposed locations had more aggressive histopathological characteristics but had longer overall survival time. This is probably due to individualised therapeutic treatment with both surgery and ECT.

VEGF Expression, Cellular Infiltration, and Intratumoral Collagen Levels after Electroporation-Based Treatment of Dogs with Cutaneous Squamous Cell Carcinoma

Canine cutaneous squamous cell carcinoma (SCC) is the most common type of skin cancer in tropical countries and is generally associated with exposure to solar ultraviolet light. It has a low metastatic rate, and local treatments, such as electrochemotherapy (ECT), promote long-term control or even complete remission. This study aimed to evaluate pre- and post-ECT treatment expression levels of vascular endothelial growth factor (VEGF) and CD31, cellular infiltration, and intratumoral collagen levels in dogs with cutaneous SCC. A prospective nonrandomized clinical study was performed using dogs with spontaneous SCC treated with ECT. Eighteen lesions from 11 dogs were included in the study. The expression levels of VEGF and CD31; cellular infiltration; and intratumoral collagen levels, as determined by Masson’s trichrome staining, were not significantly different from pre-treatment measurements on day 21 (p > 0.05). However, among cellular infiltration, the mixed subtype was correlated with better overall survival time when compared to lymphoplasmacytic and neutrophilic infiltration (p < 0.05). In conclusion, ECT had no effect on VEGF expression, cellular infiltration, or intratumoral collagen levels in dogs with cutaneous SCC at the time of evaluation, suggesting that early and late post-ECT-treatment phases should be considered.

Comparison of two different doses of bleomycin in electrochemotherapy protocols for feline cutaneous squamous cell carcinoma nonsegregated from ultraviolet light exposure

Cutaneous squamous cell carcinoma (cSCC) is one of the most common skin tumors in cats due to chronic exposure to ultraviolet light. Local treatments such as electrochemotherapy (ECT) promote disease control or even complete remission. We hypothesize that cats could benefit from treatments using bleomycin at reduced dosages. A prospective nonrandomized single-blind study evaluated the clinical parameters, site lesion, staging, disease-free interval (DFI) and survival time by comparing the standard dose of bleomycin (15,000 UI/m2) (n = 22) with a reduced dose (10,000 UI/m2) (n = 34) in cats with cSCC that underwent ECT as the sole treatment modality. No statistically significant difference in DFI or overall survival was observed between the 2 groups. A higher DFI was found in cats with a small tumor size (less than 0.33 cm3) compared with that for cats with a large tumor size (P = 0.045). Furthermore, a reduced overall survival time for cats with a higher stage in the standard group SG (T3 and T4) (P = 0.004) was observed when compared to that for cats with a lower stage (T1 and T2). In conclusion, ECT using both doses of bleomycin may achieve the same response rate in terms of the overall response, DFI, and overall survival.

Clinical Veterinary Boron Neutron Capture Therapy (BNCT) Studies in Dogs with Head and Neck Cancer: Bridging the Gap between Translational and Clinical Studies

Simple Summary

Boron Neutron Capture Therapy (BNCT) is a treatment for cancer based on the selective accumulation in tumor of boron compounds, followed by external irradiation with neutrons. The interaction between boron-10 and a neutron gives rise to very energetic particles that travel only a very short distance (approximately the diameter of a cell) and are lethal for the cell. In this way, BNCT damages tumor tissue selectively while preserving normal tissue. BNCT has proved effective to treat certain tumors in clinical trials worldwide, with room for improvement. Our group has worked on animal models to improve the efficacy of BNCT, in particular for head and neck cancer. Herein we performed clinical veterinary BNCT studies in five terminal dog patients with head and neck cancer with no other therapeutic option. In all cases we observed partial tumor response, clinical benefit, and extension of estimated survival time at recruitment with excellent quality of life. Toxicity associated to the treatment was mild/moderate and reversible. These studies contribute towards preparation for clinical BNCT trials for head and neck cancer in Argentina and suggest a potential role for BNCT in veterinary medicine.

Abstract

Translational Boron Neutron Capture Therapy (BNCT) studies performed by our group and clinical BNCT studies worldwide have shown the therapeutic efficacy of BNCT for head and neck cancer. The present BNCT studies in veterinary patients with head and neck cancer were performed to optimize the therapeutic efficacy of BNCT, contribute towards exploring the role of BNCT in veterinary medicine, put in place technical aspects for an upcoming clinical trial of BNCT for head and neck cancer at the RA-6 Nuclear Reactor, and assess the feasibility of employing the existing B2 beam to treat large, deep-seated tumors. Five dogs with head and neck cancer with no other therapeutic option were treated with two applications of BNCT mediated by boronophenyl-alanine (BPA) separated by 3–5 weeks. Two to three portals per BNCT application were used to achieve a potentially therapeutic dose over the tumor without exceeding normal tissue tolerance. Clinical and Computed Tomography results evidenced partial tumor control in all cases, with slight-moderate mucositis, excellent life quality, and prolongation in the survival time estimated at recruitment. These exploratory studies show the potential value of BNCT in veterinary medicine and contribute towards initiating a clinical BNCT trial for head and neck cancer at the RA-6 clinical facility.

Relationship of Galectin-3 Expression in Canine Cutaneous Squamous Cell Carcinomas with Histopathological Grading and Proliferation Indices

Squamous cell carcinoma (SCC) is a frequent malignant neoplasm of the skin that usually arises from areas of solar dermatosis. It is characterized by local invasiveness and regional lymph node metastasis, mainly in poorly differentiated tumours. Galectin-3 (Gal-3) is a lectin that is expressed in the nucleus or cytoplasm and has been identified as a prognostic tool for human neoplasms. The purpose of this study was to characterize Gal-3 expression in canine cutaneous SCCs and to investigate its relationship with tumour differentiation and cell proliferation indices. Immunohistochemical analysis of 50 SCCs for Gal-3 revealed no correlation between the localization or intensity of immunolabelling, or number of immunopositive cells, with histological grade of tumour or proliferative activity. The results suggest that Gal-3 expression is not a reliable prognostic marker for cutaneous SCC in dogs.

Controlled Drug Delivery Vehicles in Veterinary Oncology: State-of-the-Art and Future Directions

Controlled drug delivery systems can be used to carry several anticancer agents, including classical chemotherapeutic agents such as doxorubicin, paclitaxel or cisplatin, and are also used for the encapsulation of tyrosine kinase inhibitors and monoclonal antibodies. Usually, the controlled systems are used to decrease drug toxicity, increase local drug concentration or target specific organs or systems. In dogs, liposomal doxorubicin is the most known controlled drug delivery vehicle in veterinary medicine. However, several antitumor drugs can be encapsulated within these systems. Since the delivery vehicles are a relatively new topic in veterinary oncology, this review aims to discuss the current knowledge regarding the controlled drug delivery vehicles and discuss the current challenges and future direction of its use in veterinary oncology.