Clinical Implications of Immune Checkpoints and the RANK/RANK-L Signaling Pathway in High-Grade Canine Mast Cell Tumors.

Mast cell tumors (MCTs) are the most common malignant cutaneous tumors in dogs, and they present extremely variable biological behavior. The interaction between RANK, RANK-L, and immune checkpoints is frequently detected in the tumor microenvironment, and, together, they participate in every stage of cancer development. Thus, the aim of this study was to characterize the molecular profiles of PD-L1, CTLA-4, RANK/RANK-L signaling pathway, and IFN-γ in primary tumors and lymph node metastases. Formalin-fixed, paraffin-embedded slides of MCTs and metastatic lymph nodes of ten dogs were submitted to immunohistochemical investigations. The results demonstrated that the tumor microenvironment of the high-grade mast cell tumors showed moderate or intense immunolabeling of all proteins, and the lymph node metastases also showed moderate or intense immunolabeling of checkpoint proteins. In addition, MCTs larger than 3 cm were associated with intensified PD-L1 (p = 0.03) in metastatic lymph nodes and RANK-L (p = 0.049) immunoreactivity in the tumor. Furthermore, dogs with a survival time of less than 6 months showed higher PD-L1 immunoreactivity (p = 0.042). In conclusion, high-grade MCT is associated with an immunosuppressive microenvironment that exhibits elevated RANK/RANK-L signaling and enhanced immune checkpoint immunoreactivity, potentially facilitating intratumorally immune escape. These biomarkers show promise as clinical indicators of disease progression and might response to immunotherapy in dogs with high-grade MCTs, thus emphasizing their importance for guiding treatment decisions and improving outcomes.

Potential therapeutic strategies for non - muscle invasive bladder cancer based on association of intravesical immunotherapy with P-MAPA and systemic administration of cisplatin and doxorubicin

ABSTRACT The present study describes the histopathological and molecular effects of P-MAPA (Protein aggregate magnesium-ammonium phospholinoleate-palmitoleate anhydride) intravesical immunotherapy combined with systemic doxorubicin or cisplatin for treatment of non-muscle invasive bladder cancer (NMIBC) in an appropriate animal model. Our results showed an undifferentiated tumor, characterizing a tumor invading mucosa or submucosa of the bladder wall (pT1) and papillary carcinoma in situ (pTa) in the Cancer group. The histopathological changes were similar between the combined treatment with intravesical P-MAPA plus systemic Cisplatin and P-MAPA immunotherapy alone, showing decrease of urothelial neoplastic lesions progression and histopathological recovery in 80% of the animals. The animals treated systemically with cisplatin or doxorubicin singly, showed 100% of malignant lesions in the urinary bladder. Furthemore, the combined treatment with P-MAPA and Doxorubicin showed no decrease of urothelial neoplastic lesions progression and histopathological recovery. Furthermore, Akt, PI3K, NF-kB and VEGF protein levels were significantly lower in intravesical P-MAPA plus systemic cisplatin and in intravesical P-MAPA alone treatments than other groups. In contrast, PTEN protein levels were significantly higher in intravesical P-MAPA plus systemic cisplatin and in intravesical P-MAPA alone treatments. Thus, it could be concluded that combination of intravesical P-MAPA immunotherapy and systemic cisplatin in the NMIBC animal model was effective, well tolerated and showed no apparent signs of antagonism between the drugs. In addition, intravesical P-MAPA immunotherapy may be considered as a valuable option for treatment of BCG unresponsive patients that unmet the criteria for early cystectomy.

Potential therapeutic strategies for non - muscle invasive bladder cancer based on association of intravesical immunotherapy with p - mapa and systemic administration of cisplatin and doxorubicin.

The present study describes the histopathological and molecular effects of P-MAPA (Protein aggregate magnesium-ammonium phospholinoleate-palmitoleate anhydride) intravesical immunotherapy combined with systemic doxorubicin or cisplatin for treatment of non-muscle invasive bladder cancer (NMIBC) in an appropriate animal model. Our results showed an undifferentiated tumor, characterizing a tumor invading mucosa or submucosa of the bladder wall (pT1) and papillary carcinoma in situ (pTa) in the Cancer group. The histopathological changes were similar between the combined treatment with intravesical P-MAPA plus systemic Cisplatin and P-MAPA immunotherapy alone, showing decrease of urothelial neoplastic lesions progression and histopathological recovery in 80% of the animals. The animals treated systemically with cisplatin or doxorubicin singly, showed 100% of malignant lesions in the urinary bladder. Furthemore, the combined treatment with P-MAPA and Doxorubicin showed no decrease of urothelial neoplastic lesions progression and histopathological recovery. Furthermore, Akt, PI3K, NF-kB and VEGF protein levels were significantly lower in intravesical P-MAPA plus systemic cisplatin and in intravesical P-MAPA alone treatments than other groups. In contrast, PTEN protein levels were significantly higher in intravesical P-MAPA plus systemic cisplatin and in intravesical P-MAPA alone treatments. Thus, it could be concluded that combination of intravesical P-MAPA immunotherapy and systemic cisplatin in the NMIBC animal model was effective, well tolerated and showed no apparent signs of antagonism between the drugs. In addition, intravesical P-MAPA immunotherapy may be considered as a valuable option for treatment of BCG unresponsive patients that unmet the criteria for early cystectomy.

Purification and inflammatory edema induced by two PLA2 (Anch TX-I and Anch TX-II) from sea anemone Anthothoe chilensis (Actiniaria: Sagartiidae).

The Anch TX-I and II PLA(2) were purified from Anthothoe chilensis (Lesson, 1830) from the extract of the anemone after only two chromatographic step using molecular exclusion chromatography (Sephadex G-75) and reverse phase HPLC on µ-Bondapak C18 column. Both PLA(2) showed a molecular mass of ~14kDa determined by MALDI-TOF mass spectrometry and showed a high catalytic activity (data not showed). Although homologous with mammalian or snake venom group I PLA(2)s, Anch TX-I and II is sufficiently structurally different for the question of its placement into the existing PLA(2) classification scheme to arise. In addition, Anch TX-I and II, despite possessing many common structural features, also differ in some important structural properties. The amino acid sequence of both PLA(2) (Anch TX-I and III) showed high amino acid sequence identity with PLA(2)Rhopilema nomadica and Bunodosoma caissarum Cnidaria and PLA(2) of group III protein isolated from the Mexican lizard Heloderma horridum horridum and Heloderma suspectum. In addition, Anch TX-I and Anch TX-II showed high amino acid sequence identity with PLA(2) from group III also showed significant overall homology to bee Apis dorsata, Bombus terrestris and Bombus pennsylvanicus and PLA(2). We also investigated the in vivo edematogenic activity of Anch TX-I and Anch TX-II in a model of paw and skin edema in rats and observed that both are able to induce dose-dependent edema.