Tamm-Horsfall protein as a novel antitumor therapy for triple negative breast cancer

MERCOGLIANO, MARÍA FLORENCIA; BRUNI, SOFIA; DE MARTINO, MARA; CAVANA, ELENA ; BALANIAN, LILIANA; SOJO, EMILIO; INSERRA, FELIPE; GROISMAN, JOSÉ; SCHILLACI, ROXANA

New Orleans

Congreso; American Association for Cancer Research Annual Meeting 2022; 2022

Tamm-Horsfall Protein (THP) is expressed exclusively in the kidney and constitutes the most abundant protein in urine. An important role for THP in antibacterial host defense but also in inflammatory disorders of the urogenital tract has been suggested. In line with this, THP has been shown to potently activate macrophages and dendritic cells (and to regulate the innate and adaptive immunity in the urinary tract. Taking into account these immunostimulatory activities, we hypothesize that systemic THP administration can promote an antitumor and antimetastatic response. For that purpose we used the murine triple-negative breast cancer (TNBC) model 4T1, and the human MDA-MB-231 cell line. THP was isolated from sterile human urine of healthy individuals at a purity of >96%, and contained less than 0.06 U/ml of endotoxin. Proliferation and migration assays were performed by cell count and wound healing, respectively. The in vivo experiments were performed administrating THP 3 times a week and/or docetaxel (Dx) at 15 mg/kg twice a week in BALB/c mice bearing 4T1 tumors (50-75 mm2) and tumor growth and lung metastasis or survival were determined.We treated murine J744 macrophages and human monocytes with 10 ug/ml and 100 ug/ml THP for 18h and tumor necrosis factor levels were determined by ELISA. The former reached 0.9ng/ml and 1,4 ng/ml and the latter reached 4.5 ng/ml and 6 ng/ml, confirming the macrophage-stimulating properties of THP. We cultured 4T1 and MDA-MB-231 cells for 4 days in presence of 100 ug/ml THP and observed a reduction of cell count of 62% and 40%, respectively. The migration of the cells in cells treated with 100 ug/ml THP for 18h was evaluated. The percentage of coved area was inhibited by 70% in 4T1 cells and by 30% in MDA-MB-231 cells. These data reflected THP in decreasing TNBC proliferation and migration.Then, we evaluated the antitumor and antimetastatic effect of THP using 4T1 tumor as a preclinical model. A dose-response curve (0.3-3 mg/kg) was performed using THP administer either s.c. or i.p.. We selected the dose of 1.5 ug/kg THP s.c. that induced 40% tumor growth inhibition and 3 ug/kg i.p. that reached a 38% tumor growth inhibition. The impact of THP on decreasing metastasis was observed in the number of lung nodules and the addition of Dx decrased even more. In the case of survival studies, when tumor reached 50 mm3 were surgically removed and two days later the animals were treated with vehicle, Dx, or Dx + THP. Log rank analysis of Kaplan-Meier plot showed a significant improve of overall survival in mice treated with Dx+THP (P= 0.011) and a trend with Dx (P=0.067). Here we showed that THP decrease TNBC cell proliferation and tumor growth, decreasing metastasis dissemination and improving Dx effect. This evidence is an important finding especially in TNBC that are only chemotherapy is the standard of care.