Expression and Prognostic Significance of Neurotrophins and Their Receptors in Canine Mammary Tumors.

Accumulating data highlight the role of neurotrophins and their receptors in human breast cancer. This family includes nerve growth factor (NGF) and brain-derived neurotrophic factor (BDNF), both synthetized as proneurotrophins (proNGF and proBDNF). (pro)NGF and (pro)BDNF initiate their biological effects by binding to both their specific receptors TrkA and TrkB, respectively, and the common receptor p75NTR. Currently, no data are available about their expression and potential role in canine mammary tumors. The aim of this study was to investigate expression of proNGF and BDNF as well as their receptors TrkA, TrkB, and p75NTR in canine mammary carcinomas, and to correlate them with clinicopathological parameters (grade, histological type, lymph node status, recurrence, and distant metastasis) and survival. Immunohistochemistry was performed on serial sections of 96 canine mammary carcinomas with antibodies against proNGF, BDNF, TrkA, TrkB, and p75NTR. Of the 96 carcinomas, proNGF expression was detected in 71 (74%), BDNF in 79 (82%), TrkA in 94 (98%), TrkB in 35 (37%), and p75NTR in 44 (46%). No association was observed between proNGF, BDNF, or TrkA expression and either clinicopathological parameters or survival. TrkB and p75NTR expression were associated with favorable clinicopathological parameters as well as better overall survival.

In vitro potentiation of doxorubicin by unseeded controlled non-inertial ultrasound cavitation.

Ultrasound-generated non-inertial cavitation has the ability to potentiate the therapeutic effects of cytotoxic drugs. We report a novel strategy to induce and regulate unseeded (without nucleation agents) non-inertial cavitation, where cavitation is initiated, monitored and regulated using a confocal ultrasound setup controlled by an instrumentation platform and a PC programmed feedback control loop. We demonstrate, using 4T1 murine mammary carcinoma as model cell line, that unseeded non-inertial cavitation potentiates the cytotoxicity of doxorubicin, one of the most potent drugs used in the treatment of solid tumors including breast cancer. Combined treatment with doxorubicin and unseeded non-inertial cavitation significantly reduced cell viability and proliferation at 72 h. A mechanistic study of the potential mechanisms of action of the combined treatment identified the presence of cavitation as required to enhance doxorubicin efficacy, but ruled out the influence of changes in doxorubicin uptake, temperature increase, hydroxyl radical production and nuclear membrane modifications on the treatment outcome. The developed strategy for the reproducible generation and maintenance of unseeded cavitation makes it an attractive method as potential preclinical and clinical treatment modality to locally potentiate doxorubicin.

CD44 and CD24 Expression and Prognostic Significance in Canine Mammary Tumors.

CD44+/CD24- phenotype has been used to identify human and canine mammary cancer stem-like cells. In canine mammary tumors, CD44+/CD24- phenotype has been associated with high grade and lymph node infiltration. However, several studies have reported opposing results regarding the clinical significance of phenotypic groups formed by the combination of CD44 and CD24 in both human and canine mammary tumors. So far, no study has investigated the correlation between these phenotypes and survival in dogs. The aim of this study was to investigate the expression and distribution of CD44 and CD24 in canine mammary carcinomas and to correlate them with histological diagnosis and survival in a well-characterized cohort. Immunohistochemistry was performed in 96 mammary carcinomas with antibodies against CD44 and CD24. Expression of CD44+ and CD44+/CD24- phenotype was detected in 75 of 96 (78%) and 63 of 96 (65.6%) carcinomas, respectively. Their expression was associated with tumor type, occurring more often in tubular complex carcinomas than in solid carcinomas. CD44+/CD24- phenotype was associated with a better overall survival ( P = .001). CD24+ expression was detected in 52 of 96 tumors (54%) and CD44-/CD24+ phenotype in 39 of 96 tumors (40.6%). Both were associated with poor clinicopathological parameters (high grade, and emboli). No correlation with overall survival was observed. CD44+/CD24- expression was associated with a better prognosis and occurred at high frequency and high level, indicating that this phenotype is not suitable to detect cancer stem cells in canine mammary carcinomas. Although further studies are needed, our results suggest that CD24 may constitute a valuable marker of poor prognosis for canine mammary carcinomas.