Biosafety of mesoporous silica nanoparticles; towards clinical translation.

Mesoporous silica nanoparticles (MSNs) have attracted the attention of chemists, who have developed numerous systems for the encapsulation of a plethora of molecules, allowing the use of mesoporous silica nanoparticles for biomedical applications. MSNs have been extensively studied for their use in nanomedicine, in applications such as drug delivery, diagnosis, and bioimaging, demonstrating significant in vivo efficacy in different preclinical models. Nevertheless, for the transition of MSNs into clinical trials, it is imperative to understand the characteristics that make MSNs effective and safe. The biosafety properties of MSNs in vivo are greatly influenced by their physicochemical characteristics such as particle shape, size, surface modification, and silica framework. In this review, we compile the most relevant and recent progress in the literature up to the present by analyzing the contributions on biodistribution, biodegradability, and clearance of MSNs. Furthermore, the ongoing clinical trials and the potential challenges related to the administration of silica materials for advanced therapeutics are discussed. This approach aims to provide a solid overview of the state-of-the-art in this field and to encourage the translation of MSNs to the clinic.

Preclinical evaluation of Insulin-like growth factor receptor 1 (IGF1R) and Insulin Receptor (IR) as a therapeutic targets in triple negative breast cancer.

Triple Negative Breast Cancer (TNBC), a subtype of breast cancer, has fewer successful therapeutic therapies than other types of breast cancer. Insulin-like growth factor receptor 1 (IGF1R) and the Insulin receptor (IR) are associated with poor outcomes in TNBC. Targeting IGF1R has failed clinically. We aimed to test if inhibiting both IR/IGF1R was a rationale therapeutic approach to treat TNBC. We showed that despite IGF1R and IR being expressed in TNBC, their expression is not associated with a negative survival outcome. Furthermore, targeting both IR/IGF1R with inhibitors in multiple TNBC cell lines did not inhibit cell growth. Linsitinib, a small molecule inhibitor of both IGF1R and IR, did not block tumour formation and had no effect on tumour growth in vivo. Cumulatively these data suggest that while IGF1R and IR are expressed in TNBC, they are not good therapeutic targets. A potential reason for the limited anti-cancer impact when IR/IGF1R was targeted may be because multiple signalling pathways are altered in TNBC. Therefore, targeting individual signalling pathways may not be sufficient to inhibit cancer growth.

Combination of palbociclib with navitoclax based-therapies enhances in vivo antitumoral activity in triple-negative breast cancer.

Triple-negative breast cancer (TNBC) is a very aggressive subtype of breast cancer with a poor prognosis and limited effective therapeutic options. Induction of senescence, arrest of cell proliferation, has been explored as an effective method to limit tumor progression in metastatic breast cancer. However, relapses occur in some patients, possibly as a result of the accumulation of senescent tumor cells in the body after treatment, which promote metastasis. In this study, we explored the combination of senescence induction and the subsequent removal of senescent cells (senolysis) as an alternative approach to improve outcomes in TNBC patients. We demonstrate that a combination treatment, using the senescence-inducer palbociclib and the senolytic agent navitoclax, delays tumor growth and reduces metastases in a mouse xenograft model of aggressive human TNBC (hTNBC). Furthermore, considering the off-target effects and toxicity derived from the use of navitoclax, we propose a strategy aimed at minimizing the associated side effects. We use a galacto-conjugated navitoclax (nav-Gal) as a senolytic prodrug that can preferentially be activated by ß-galactosidase overexpressed in senescent cells. Concomitant treatment with palbociclib and nav-Gal in vivo results in the eradication of senescent hTNBC cells with consequent reduction of tumor growth, while reducing the cytotoxicity of navitoclax. Taken together, our results support the efficacy of combination therapy of senescence-induction with senolysis for hTNBC, as well as the development of a targeted approach as an effective and safer therapeutic opportunity.

Pharmacological senolysis reduces doxorubicin-induced cardiotoxicity and improves cardiac function in mice.

Many anticancer agents used in clinics induce premature senescence in healthy tissues generating accelerated aging processes and adverse side-effects in patients. Cardiotoxicity is a well-known limiting factor of anticancer treatment with doxorubicin (DOX), a very effective anthracycline widely used as antitumoral therapy in clinical practice, that leads to long-term morbidity and mortality. DOX exposure severely affects the population of cardiac cells in both mice and human hearts by inducing premature senescence, which may represent the molecular basis of DOX-induced cardiomyopathy. Here, we demonstrate that senescence induction in the heart contributes to impaired cardiac function in mice upon DOX treatment. Concomitant elimination of senescent cells with the senolytic Navitoclax in different formulations produces a significant decrease in senescence and cardiotoxicity markers together with the restoration of the cardiac function in mice followed by echocardiography. These results evidence the potential clinical use of senolytic therapies to alleviate cardiotoxicities induced in chemotherapy-treated patients.