BackgroundAlthough multimodality treatment can induce high rate of remission in many subtypes of non-Hodgkin's lymphoma (NHL), significant proportions of patients relapse with incurable disease. The effect of human bone marrow (BM) mesenchymal stem cells (MSC) on tumor cell growth is controversial, and no specific information is available on the effect of BM-MSC on NHL.Methodology/Principal FindingsThe effect of BM-MSC was analyzed in two in vivo models of disseminated non-Hodgkin's lymphomas with an indolent (EBV− Burkitt-type BJAB, median survival = 46 days) and an aggressive (EBV+ B lymphoblastoid SKW6.4, median survival = 27 days) behavior in nude-SCID mice. Intra-peritoneal (i.p.) injection of MSC (4 days after i.p. injection of lymphoma cells) significantly increased the overall survival at an optimal MSC∶lymphoma ratio of 1∶10 in both xenograft models (BJAB+MSC, median survival = 58.5 days; SKW6.4+MSC, median survival = 40 days). Upon MSC injection, i.p. tumor masses developed more slowly and, at the histopathological observation, exhibited a massive stromal infiltration coupled to extensive intra-tumor necrosis. In in vitro experiments, we found that: i) MSC/lymphoma co-cultures modestly affected lymphoma cell survival and were characterized by increased release of pro-angiogenic cytokines with respect to the MSC, or lymphoma, cultures; ii) MSC induce the migration of endothelial cells in transwell assays, but promoted endothelial cell apoptosis in direct MSC/endothelial cell co-cultures.Conclusions/SignificanceOur data demonstrate that BM-MSC exhibit anti-lymphoma activity in two distinct xenograft SCID mouse models of disseminated NHL.

SARS-CoV-2 infection affects different organs and tissues, including the upper and lower airways, the lung, the gut, the olfactory system and the eye, which may represent one of the gates to the central nervous system. Key transcriptional factors, such as p53 and NF-kB and their reciprocal balance, are altered upon SARS-CoV-2 infection, as well as other key molecules such as the virus host cell entry mediator ACE2, member of the RAS-pathway. These changes are thought to play a central role in the impaired immune response, as well as in the massive cytokine release, the so-called cytokine storm that represents a hallmark of the most severe form of SARS-CoV-2 infection. Host genetics susceptibility is an additional key side to consider in a complex disease as COVID-19 characterized by such a wide range of clinical phenotypes. In this review, we underline some molecular mechanisms by which SARS-CoV-2 modulates p53 and NF-kB expression and activity in order to maximize viral replication into the host cells. We also face the RAS-pathway unbalance triggered by virus-ACE2 interaction to discuss potential pharmacological and pharmacogenomics approaches aimed at restoring p53/NF-kB and ACE1/ACE2 balance to counteract the most severe forms of SARS-CoV-2 infection.

Purpose: Because the nongenotoxic inhibitor of the p53/MDM2 interactions Nutlin-3 has shown promising in vitro therapeutic activity against a variety of p53 wild-type cancer cells, in this study we evaluated an innovative strategy able to specifically target Nutlin-3 toward CD20 þ malignant cells.Experimental Design: The cytotoxic effects of Nutlin-3 encapsulated into poly(lactide-co-glycolide) nanoparticles (NP-Nut) and into rituximab (anti-CD20 antibody)-engineered NP (NP-Rt-Nut) as well as of NPs engineered with rituximab alone (NP-Rt) were initially analyzed in vitro in JVM-2 B-leukemic cells, by assessing both the functional activation of the p53 pathway (by Nutlin-3) and/or the activation of the complement cascade (by rituximab). Moreover, the potential therapeutic efficacy of NP-Nut, NP-Rt, and NPRt-Nut were comparatively assessed in vivo in CD20 þ JVM-2 leukemic xenograft SCID mice.Results: Functional in vitro assays showed that NP-Nut and NP-Rt-Nut exhibited a comparable ability to activate the p53 pathway in the p53 wild-type JVM-2 leukemic cells. On the other hand, NP-Rt and NPRt-Nut, but not NP nor NP-Nut, were able to promote activation of the complement cascade. Of note, the in vivo intratumoral injection in JVM-2 B-leukemic/xenograft mice showed that NP-Rt-Nut displayed the maximal therapeutic activity promoting a survival rate significantly higher not only with respect to control animals, treated either with vehicle or with empty NP, but also with respect to animals treated with NP-Nut or NP-Rt. Conclusions: Our data show for the first time the potential antileukemic activity of rituximabengineered Nutlin-3-loaded NPs in xenograft SCID mice.