The antioxidant mitochondrial protein UCP2 promotes cancer development connecting theWarburg effect and autophagy

Mitochondrial anion transporter proteins localized into the mitochondrial inner membrane. Currently, five UCP family members have been identified in mammals.Among them, UCP2 is widely distributedthroughout the organism, suggesting different and wide functions for this mitochondrial uncoupling protein. Basically, the antioxidant role of UCP2 is due to its capability to decrease the mitochondrial potential and to dissipate the proton gradient

Mutant p53-Associated Molecular Mechanisms of ROS Regulation in Cancer Cells

The TP53 tumor suppressor gene is the most frequently altered gene in tumors and an increasing number of studies highlight that mutant p53 proteins can acquire oncogenic properties, referred to as gain-of-function (GOF). Reactive oxygen species (ROS) play critical roles as intracellular messengers, regulating numerous signaling pathways linked to metabolism and cell growth. Tumor cells frequently display higher ROS levels compared to healthy cells as a result of their increased metabolism as well as serving as an oncogenic agent because of its damaging and mutational properties. Several studies reported that in contrast with the wild type protein, mutant p53 isoforms fail to exert antioxidant activities and rather increase intracellular ROS, driving a pro-tumorigenic survival. These pro-oxidant oncogenic abilities of GOF mutant p53 include signaling and metabolic rewiring, as well as the modulation of critical ROS-related transcription factors and antioxidant systems, which lead ROS unbalance linked to tumor progression. The studies summarized here highlight that GOF mutant p53 isoforms might constitute major targets for selective therapeutic intervention against several types of tumors and that ROS enhancement driven by mutant p53 might represent an "Achilles heel" of cancer cells, suggesting pro-oxidant drugs as a therapeutic approach for cancer patients bearing the mutant TP53 gene

To metabolomics and beyond: a technological portfolio to investigate cancer metabolism

Tumour cells have exquisite flexibility in reprogramming their metabolism in order to support tumour initiation, progression, metastasis and resistance to therapies. These reprogrammed activities include a complete rewiring of the bioenergetic, biosynthetic and redox status to sustain the increased energetic demand of the cells. Over the last decades, the cancer metabolism field has seen an explosion of new biochemical technologies giving more tools than ever before to navigate this complexity. Within a cell or a tissue, the metabolites constitute the direct signature of the molecular phenotype and thus their profiling has concrete clinical applications in oncology. Metabolomics and fluxomics, are key technological approaches that mainly revolutionized the field enabling researchers to have both a qualitative and mechanistic model of the biochemical activities in cancer. Furthermore, the upgrade from bulk to single-cell analysis technologies provided unprecedented opportunity to investigate cancer biology at cellular resolution allowing an in depth quantitative analysis of complex and heterogenous diseases. More recently, the advent of functional genomic screening allowed the identification of molecular pathways, cellular processes, biomarkers and novel therapeutic targets that in concert with other technologies allow patient stratification and identification of new treatment regimens. This review is intended to be a guide for researchers to cancer metabolism, highlighting current and emerging technologies, emphasizing advantages, disadvantages and applications with the potential of leading the development of innovative anti-cancer therapies

Role-shifting PKCζ fosters its own proapoptotic destruction by complexing with Bcl10 protein at the nuclear envelope of human cervical carcinoma cells

Many features of deadly human cervical cancers (HCCs) still require elucidation. Among HCC-derived cell lines, here we used the C4-I one since its quantitative gene expression pattern most closely mimics invasive HCCs, including protein kinase-Cζ (PKCζ) overexpression. Via proteomic, bioinformatic, and biochemical approaches (see for technical details [1,2]) we identified 31 and 33 proteins coimmunoprecipitating with PKCζ from nuclear membranes (NMs) of, respectively, untreated or VP- 16-exposed C4-I cells. Such proteins belonged to eight functional groups, whose compositions and relative sizes changed with either context. Of the 56 proteins identified, only eight were shared between the two subproteomes, including Bcl10. Surprisingly, proteins known to associate with Bcl10, like Carma1/3 and Malt1 in so called CBM signalosomes were absent. Notably, in VP-16-treated C4-I cells, PKCζ•Bcl10 complexes increasingly accrued at NMs, where PKCζ phosphorylated Bcl10—as PKCζ also did in vitro and in cell-free systems—both processes being thwarted by interfering RNA (iRNA) PKCζ depletion. Caspase-3 was associated with PKCζ•Bcl10 complexes and proteolyzed PKCζ leading to its inactiv-ation/destruction—both events were prevented by Bcl10 iRNA suppression. Thus, PKCζ’s molecular interactions and functional roles changed strikingly according to the untreated or apoptogen-treated cells context, and by complexing with Bcl10, PKCζ surprisingly favored its own demise, which suggests both proteins as HCCs therapeutic targets

Calcium-sensing receptor antagonist (calcilytic) NPS 2143 prevents the increased secretion of endogenous Aβ42 prompted by exogenous Aβ25-35 in human cortical astrocytes and neurons

Previously we showed that adding fibrillar (f)Aβ25–35, a proxy retaining the main physical and biological features of Aβ42, stimulated untransformed astrocytes isolated from fragments of the adult human temporal lobe cerebral cortex to synthesize and accumulate large amounts of endogenous Aβ42 and its oligomers, while releasing excess amounts of nitric oxide (NO) and of vascular endothelial growth factor (VEGF-A) [1,2]. Here, we investigated the effects of fAβ25-35 and soluble (s)Aβ25-35 on Aβ42 and Aβ40 accumulation/secretion by human cortical astrocytes and HCN- 1A neurons. And since the calcium-sensing receptor (CaSR) binds Aβs, we studied whether calcium-CaSR signaling plays any role in such Aβ25-35-elicited effects and their modulation by NPS 2143, a CaSR allosteric antagonist (calcilytic). The fAβ25- 35-exposed astrocytes and neurons produced, accumulated, and secreted increased amounts of Aβ42, while Aβ40 also accrued but its secretion was unchanged. Accordingly, secreted Aβ42/Aβ40 ratio values rose for astrocytes and neurons but NPS 2143 addition specifically suppressed the fAβ25-35-elicited surges of endogenous Aβ42 secretion by both cell types. Therefore, NPS 2143 addition always kept Aβ42/Aβ40 values to baseline or lower levels. Compared to fAβ25-35, sAβ25-35 also stimulated Aβ42 secretion by astrocytes and neurons and NPS 2143 specifically and wholly suppressed this effect. Therefore, since NPS 2143 prevents any Aβ/CaSR-induced surplus secretion of endogenous Aβ42 and hence further vicious cycles of Aβ self-induction/secretion/ spreading, the CaSR antagonists like NPS 2143 might be novel therapeutic drugs for Alzheimer’s disease

Homing of peripherally injected bone marrow cells in rat after experimental myocardial injury

Background and objectives: significant progress has been achieved during the past 10 years in cell transplantation and recent research has focused on the possibility of improving ventricular function after myocardial infarction. Most studies in the field of cardiac tissue repair are performed by direct intramyocardial injection of cells of different origin. Since this approach requires a surgical intervention, in this study we investigated the feasibility of non-invasive administration of bone marrow mononuclear cells (BMMNCs) by assessing the fate of peripherally injected, purified, labeled cells in cryodamaged hearts. Design and methods: ten donor and ten recipient inbred isogenic adult (4 weeks old) Fisher rats were used as models to mimic autologous transplantation. Myocardial damage was obtained in recipient rats by placing a frozen metal probe on the anterior left ventricular wall for 15 seconds (freeze-thaw injury technique). BMMNCs were purified and labeled with a red fluorescent cell dye. Seven days after the injury about 15-25x10(6) cells were infused through the femoral vein of recipient rats. Seven days after the infusion, the heart, lungs, liver, kidneys, spleen and thymus were harvested to track transplanted cells. RESULTS: Labeled cells were found only in the injured area of the heart and not in the normal tissue, and a limited number of cells were identified in the spleen of all the animals. Most of the labeled cells in the infarcted area were Thy-1(+) and some were CD34(+). Interpretation and conclusions: our data suggest that peripherally injected BMMNCs can traffic through the circulation to the site of damage; we hypothesize that tissue injury leads to the priming of a cytokine cascade acting as chemoattractant for the infused cells

3-Bromo-Isoxazoline Derivatives Inhibit GAPDH Enzyme in PDAC Cells Triggering Autophagy and Apoptotic Cell Death

A growing interest in the study of aerobic glycolysis as a key pathway for cancer-cell energetic metabolism, favouring tumour progression and invasion, has led to consider GAPDH as an effective drug target to specifically hit cancer cells. In this study, we have investigated a panel of 3-bromo-isoxazoline derivatives based on previously identified inhibitors of Plasmodium falciparum GAPDH (PfGAPDH). The compounds are active, to a different extent, as inhibitors of human-recombinant GAPDH. They showed an antiproliferative effect on pancreatic ductal-adenocarcinoma cells (PDAC) and pancreatic-cancer stem cells (CSCs), and among them two promising compounds were selected to be tested in vivo. Interestingly, these compounds were not effective in fibroblasts. The AXP-3019 derivative was able to block PDAC-cell growth in mice xenograft without apparent toxicity. The overall results support the assumption that selective inhibition of the glycolytic pathway, by targeting GAPDH, is an effective therapy for pancreatic cancer and that 3-bromo-isoxazoline derivatives represent a new class of anti-cancer compounds targeting glycolysis

Extracellular matrix composition modulates the responsiveness of differentiated and stem pancreatic cancer cells to lipophilic derivate of gemcitabine

Background: Pancreatic ductal adenocarcinoma (PDAC) is a highly lethal disease. Gemcitabine (GEM) is used as the gold standard drug in PDAC treatment. However, due to its poor efficacy, it remains urgent to identify novel strategies to overcome resistance issues. In this context, an intense stroma reaction and the presence of cancer stem cells (CSCs) have been shown to influence PDAC aggressiveness, metastatic potential, and chemoresistance. Methods: We used three-dimensional (3D) organotypic cultures grown on an extracellular matrix composed of Matrigel or collagen I to test the effect of the new potential therapeutic prodrug 4-(N)-stearoyl-GEM, called C18GEM. We analyzed C18GEM cytotoxic activity, intracellular uptake, apoptosis, necrosis, and autophagy induction in both Panc1 cell line (P) and their derived CSCs. Results: PDAC CSCs show higher sensitivity to C18GEM treatment when cultured in both two-dimensional (2D) and 3D conditions, especially on collagen I, in comparison to GEM. The intracellular uptake mechanisms of C18GEM are mainly due to membrane nucleoside transporters' expression and fatty acid translocase CD36 in Panc1 P cells and to clathrin-mediated endocytosis and CD36 in Panc1 CSCs. Furthermore, C18GEM induces an increase in cell death compared to GEM in both cell lines grown on 2D and 3D cultures. Finally, C18GEM stimulated protective autophagy in Panc1 P and CSCs cultured on 3D conditions. Conclusion: We propose C18GEM together with autophagy inhibitors as a valid alternative therapeutic approach in PDAC treatment

Tumor Suppressor Role of Wild-Type P53-Dependent Secretome and Its Proteomic Identification in PDAC

: The study of the cancer secretome is gaining even more importance in cancers such as pancreatic ductal adenocarcinoma (PDAC), whose lack of recognizable symptoms and early detection assays make this type of cancer highly lethal. The wild-type p53 protein, frequently mutated in PDAC, prevents tumorigenesis by regulating a plethora of signaling pathways. The importance of the p53 tumor suppressive activity is not only primarily involved within cells to limit tumor cell proliferation but also in the extracellular space. Thus, loss of p53 has a profound impact on the secretome composition of cancer cells and marks the transition to invasiveness. Here, we demonstrate the tumor suppressive role of wild-type p53 on cancer cell secretome, showing the anti-proliferative, apoptotic and chemosensitivity effects of wild-type p53 driven conditioned medium. By using high-resolution SWATH-MS technology, we characterized the secretomes of p53-deficient and p53-expressing PDAC cells. We found a great number of secreted proteins that have known roles in cancer-related processes, 30 of which showed enhanced and 17 reduced secretion in response to p53 silencing. These results are important to advance our understanding on the link between wt-p53 and cancer microenvironment. In conclusion, this approach may detect a secreted signature specifically driven by wild-type p53 in PDAC

Autocrine mechanisms of cancer chemoresistance

An ever-increasing number of studies highlight the role of cancer secretome in the modification of tumour microenvironment and in the acquisition of cancer cell resistance to therapeutic drugs. The knowledge of the mechanisms underlying the relationship between cancer cell-secreted factors and chemoresistance is becoming fundamental for the identification of novel anticancer therapeutic strategies overcoming drug resistance and novel prognostic secreted biomarkers. In this review, we summarize the novel findings concerning the regulation of secreted molecules by cancer cells compromising drug sensitivity. In particular, we highlight data from available literature describing the involvement of cancer cell-secreted molecules determining chemoresistance in an autocrine manner, including: i) growth factors; ii) glycoproteins; iii) inflammatory cytokines; iv) enzymes and chaperones; and v) tumor-derived exosomes