Promising pharmacological profile of a Kunitz-type inhibitor in murine renal cell carcinoma model

Abstract

Renal cell carcinoma (RCC), also called kidney cancer or renal adenocarcinoma, is highly resistant to current treatments. It has been previously reported that a Kunitz-type inhibitor domain-containing protein, isolated from the salivary glands of the Amblyomma cajennense tick, triggers apoptosis in murine renal adenocarcinoma cells (Renca) by inhibiting the proteasome and endoplasmic reticulum stress. Of note, Amblyomin-X is the corresponding recombinant protein identified in the cDNA library from A. cajennense salivary glands. Herein, using orthotopic kidney tumors in mice, we demonstrate that Amblyomin-X is able to drastically reduce the incidence of lung metastases by inducing cell cycle arrest and apoptosis. The in vitro assays show that Amblyomin-X is capable of reducing the proliferation rate of Renca cells, promoting cell cycle arrest, and down-regulating the expression of crucial proteins (cyclin D1, Ki67 and Pgp) involved in the aggressiveness and resistance of RCC. Regarding non-tumor cells (NIH3T3), Amblyomin-X produced minor effects in the cyclin D1 levels. Interestingly, observing the image assays, the fluorescence-labelled Amblyomin-X was indeed detected in the tumor stroma whereas in healthy animals it was rapidly metabolized and excreted. Taken the findings together, Amblyomin-X can be considered as a potential anti-RCC drug candidate.

Modulation of stress and immune response by Amblyomin-X results in tumor cell death in a horse melanoma model

“…Our results validated previous uses of Amblyomin-X against several tumor cell lines including skin melanoma [15][16][17][18]42 like ER-stress, Mitochondria-stress, and Apoptosis. It is important to note that the transcriptome results presented herein are the mean cell expression values in the tumor's core, a complex system composed of many distinct normal cells surrounding tumor cells.…”

“…This molecule has the ability to inhibit Factor Xa in the blood coagulation cascade and triggers apoptosis by activating its intrinsic pathway in tumor cells [14][15][16] . In previous studies, Amblyomin-X showed more avidity in the recognition of tumor cells, and rapid excretion in healthy murines 17 . We have already shown that Amblyomin-X causes cell death via induction of both endoplasmic reticulum (ER) stress and proteasome inhibition (PI) in renal adenocarcinoma (murine RENCA), in melanoma (murine B16F10 and human SK-MEL-28) 18 , as well as in pancreatic (human Mia-Paca-2) tumor cell lines 17,19,20 .…”

Amblyomin-X, a recombinant Kunitz-type inhibitor, regulates cell adhesion and migration of human tumor cells

“…The current study describes cellular effects induced by Kunitz-type inhibitor associated with distinct cell motility and proteolysis pericellular biological processes in tumor and endothelial cells. We have demonstrated before that Amblyomin-X has antitumor, antithrombotic and antimetastatic activity [25][26][27][28]. Interestingly, no cytotoxic effect was reported in non-tumor cells, such as fibroblasts.…”

“…A recombinant form of this protein was shown to have strong pro-apoptotic activity in various murine and human tumor cells via endoplasmic reticulum stress (ER stress), proteasome inhibition, blockage of autophagy, cell cycle arrest, and aggregosome formation [ 22 – 24 ]. In vivo , we have shown that this inhibitor induces tumor regression and reduction of metastasis[ 25 ]. Furthermore, Amblyomin-X has no toxicity in normal cells and presents low toxicity in healthy animals [ 22 , 24 , 26 ].…”

Anticoagulants from Hematophagous

“…The prolongation of PT and aPTT is reversible [154]. Interestingly, several studies pointed out Amblyomin-X as an anti-cancer molecule in vitro and in vivo [154][155][156][157][158][159][160][161].…”