Cholesterol biosynthetic pathway induces cellular senescence through ERRα.

Cellular senescence is a cell program induced by various stresses that leads to a stable proliferation arrest and to a senescence-associated secretory phenotype. Accumulation of senescent cells during age-related diseases participates in these pathologies and regulates healthy lifespan. Recent evidences point out a global dysregulated intracellular metabolism associated to senescence phenotype. Nonetheless, the functional contribution of metabolic homeostasis in regulating senescence is barely understood. In this work, we describe how the mevalonate pathway, an anabolic pathway leading to the endogenous biosynthesis of poly-isoprenoids, such as cholesterol, acts as a positive regulator of cellular senescence in normal human cells. Mechanistically, this mevalonate pathway-induced senescence is partly mediated by the downstream cholesterol biosynthetic pathway. This pathway promotes the transcriptional activity of ERRα that could lead to dysfunctional mitochondria, ROS production, DNA damage and a p53-dependent senescence. Supporting the relevance of these observations, increase of senescence in liver due to a high-fat diet regimen is abrogated in ERRα knockout mouse. Overall, this work unravels the role of cholesterol biosynthesis or level in the induction of an ERRα-dependent mitochondrial program leading to cellular senescence and related pathological alterations.

Loss of Pla2r1 decreases cellular senescence and age-related alterations caused by aging and Western diets.

Cellular senescence is induced by many stresses including telomere shortening, DNA damage, oxidative, or metabolic stresses. Senescent cells are stably cell cycle arrested and they secrete many factors including cytokines and chemokines. Accumulation of senescent cells promotes many age-related alterations and diseases. In this study, we investigated the role of the pro-senescent phospholipase A2 receptor 1 (PLA2R1) in regulating some age-related alterations in old mice and in mice subjected to a Western diet, whereas aged wild-type mice displayed a decreased ability to regulate their glycemia during glucose and insulin tolerance tests, aged Pla2r1 knockout (KO) mice efficiently regulated their glycemia and displayed fewer signs of aging. Loss of Pla2r1 was also found protective against the deleterious effects of a Western diet. Moreover, these Pla2r1 KO mice were partially protected from diet-induced senescent cell accumulation, steatosis, and fibrosis. Together these results support that Pla2r1 drives several age-related alterations, especially in the liver, arising during aging or through a Western diet.

NFL-TBS.40-63 Peptide Gold Complex Nanovector: A Novel Therapeutic Approach to Increase Anticancer Activity by Breakdown of Microtubules in Pancreatic Adenocarcinoma (PDAC).

The role of the NFL-TBS.40-63 peptide is to destroy the microtubule network of target glioma cancer cells. Recently, we have conceived a gold-complex biotinylated NFL-TBS.40-63 (BIOT-NFL) to form a hybrid gold nanovector (BIOT-NFL-PEG-AuNPs). This methodology showed, for the first time, the ability of the BIOT-NFL-PEG-AuNPs to target the destruction of pancreatic cancer cells (PDAC) under experimental conditions, as well as detoxification and preclinical therapeutic efficacy regulated by the steric and chemical configuration of the peptide. For this aim, a mouse transplantation tumor model induced by MIA-PACA-2 cells was applied to estimate the therapeutic efficacy of BIOT-NFL-PEG-AuNPs as a nanoformulation. Our relevant results display that BIOT-NFL-PEG-AuNPs slowed the tumor growth and decreased the tumor index without effects on the body weight of mice with an excellent antiangiogenic effect, mediated by the ability of BIOT-NFL-PEG-AuNPs to alter the metabolic profiles of these MIA-PACA-2 cells. The cytokine levels were detected to evaluate the behavior of serum inflammatory factors and the power of BIOT-NFL-PEG-AuNPs to boost the immune system.

Cell penetrating peptide (CPP) gold(iii) - complex - bioconjugates: from chemical design to interaction with cancer cells for nanomedicine applications.

This study promotes an innovative synthesis of a nanotheragnostic scaffold capable of targeting and destroying pancreatic cancer cells (PDAC) using the Biotinylated NFL-TBS.40-63 peptide (BIOT-NFL), known to enter various glioblastoma cancer cells (GBM) where it specifically destroys their microtubule network. This recently proposed methodology (P7391FR00-50481 LIV) applied to other peptides VIM (Vimentin) and TAT (Twin-Arginine Translocation) (CPP peptides) has many advantages, such as targeted selective internalization and high stability under experimental conditions, modulated by steric and chemical configurations of peptides. The successful interaction of peptides on gold surfaces has been confirmed by UV-visible, dynamic light scattering (DLS), Zeta potential (ZP) and Raman spectroscopy analyses. The cellular internalization in pancreatic ductal adenocarcinoma (PDAC; MIA PACA-2) and GBM (F98) cells was monitored by transmission electron microscopy (TEM) and showed a better cellular internalization in the presence of peptides with gold nanoparticles. In this work, we also evaluated the power of these hybrid peptide-nanoparticles as photothermal agents after cancer cell internalization. These findings envisage novel perspectives for the development of high peptide-nanotheragnostics.

Cell penetrating peptide decorated magnetic porous silicon nanorods for glioblastoma therapy and imaging.

Glioblastoma multiforme (GBM) is the most malignant primary brain tumor of the central nervous system. Despite advances in therapy, it remains largely untreatable, in part due to the low permeability of chemotherapeutic drugs across the blood-brain barrier (BBB) which significantly compromises their effectiveness. To circumvent the lack of drug efficiency, we designed multifunctional nanoparticles based on porous silicon. Herein, we propose an innovative synthesis technique for porous silicon nanorods (pSiNRs) with three-dimensional (3D) shape-controlled nanostructure. In order to achieve an efficient administration and improved treatment against GBM cells, a porous silicon nanoplatform is designed with magnetic guidance, fluorescence tracking and a cell-penetrating peptide (CPP). A NeuroFilament Light (NFL) subunit derived 24 amino acid tubulin binding site peptide called NFL-TBS.40-63 peptide or NFL-peptide was reported to preferentially target human GBM cells compared to healthy cells. Motivated by this approach, we investigated the use of magnetic-pSiNRs covered with superparamagnetic iron oxide nanoparticles (SPIONs) for magnetic guidance, then decorated with the NFL-peptide to facilitate targeting and enhance internalization into human GBM cells. Unexpectedly, under confocal microscope imaging, the internalized multifunctional nanoparticles in GBM cells induce a remarkable exaltation of green fluorescence instead of the red native fluorescence from the dye due to a possible Förster resonance energy transfer (FRET). In addition, we showed that the uptake of NFL-peptide decorated magnetic-pSiNRs was preferential towards human GBM cells. This study presents the fabrication of magnetic-pSiNRs decorated with the NFL-peptide, which act as a remarkable candidate to treat brain tumors. This is supported by in vitro results and confocal imaging.

Calcium channel ITPR2 and mitochondria-ER contacts promote cellular senescence and aging.

Cellular senescence is induced by stresses and results in a stable proliferation arrest accompanied by a pro-inflammatory secretome. Senescent cells accumulate during aging, promoting various age-related pathologies and limiting lifespan. The endoplasmic reticulum (ER) inositol 1,4,5-trisphosphate receptor, type 2 (ITPR2) calcium-release channel and calcium fluxes from the ER to the mitochondria are drivers of senescence in human cells. Here we show that Itpr2 knockout (KO) mice display improved aging such as increased lifespan, a better response to metabolic stress, less immunosenescence, as well as less liver steatosis and fibrosis. Cellular senescence, which is known to promote these alterations, is decreased in Itpr2 KO mice and Itpr2 KO embryo-derived cells. Interestingly, ablation of ITPR2 in vivo and in vitro decreases the number of contacts between the mitochondria and the ER and their forced contacts induce premature senescence. These findings shed light on the role of contacts and facilitated exchanges between the ER and the mitochondria through ITPR2 in regulating senescence and aging.

PLA2R1 promotes DNA damage and inhibits spontaneous tumor formation during aging.

Although aging is a major risk factor for most types of cancers, it is barely studied in this context. The transmembrane protein PLA2R1 (phospholipase A2 receptor) promotes cellular senescence, which can inhibit oncogene-induced tumor initiation. Functions and mechanisms of action of PLA2R1 during aging are largely unknown. In this study, we observed that old Pla2r1 knockout mice were more prone to spontaneously develop a wide spectrum of tumors compared to control littermates. Consistently, these knockout mice displayed increased Parp1, a master regulator of DNA damage repair, and decreased DNA damage, correlating with large human dataset analysis. Forced PLA2R1 expression in normal human cells decreased PARP1 expression, induced DNA damage and subsequent senescence, while the constitutive expression of PARP1 rescued cells from these PLA2R1-induced effects. Mechanistically, PARP1 expression is repressed by a ROS (reactive oxygen species)-Rb-dependent mechanism upon PLA2R1 expression. In conclusion, our results suggest that PLA2R1 suppresses aging-induced tumors by repressing PARP1, via a ROS-Rb signaling axis, and inducing DNA damage and its tumor suppressive responses.

The JAK1/2 inhibitor ruxolitinib delays premature aging phenotypes.

Hutchinson-Gilford progeria syndrome (HGPS) is caused by an LMNA mutation that results in the production of the abnormal progerin protein. Children with HGPS display phenotypes of premature aging and have an average lifespan of 13 years. We found earlier that the targeting of the transmembrane protein PLA2R1 overcomes senescence and improves phenotypes in a mouse model of progeria. PLA2R1 is regulating the JAK/STAT signaling, but we do not yet know whether targeting this pathway directly would influence cellular and in vivo progeria phenotypes. Here, we show that JAK1/2 inhibition with ruxolitinib rescues progerin-induced cell cycle arrest, cellular senescence, and misshapen nuclei in human normal fibroblasts expressing progerin. Moreover, ruxolitinib administration reduces several premature aging phenotypes: bone fractures, bone mineral content, grip strength, and a trend to increase survival in a mouse model of progeria. Thus, we propose that ruxolitinib, an FDA-approved drug, should be further evaluated as a drug candidate in HGPS therapy.

Targeting the phospholipase A2 receptor ameliorates premature aging phenotypes.

Hutchinson-Gilford progeria syndrome (HGPS) is a lethal premature aging that recapitulates many normal aging characteristics. This disorder is caused by mutation in the LMNA gene leading to the production of progerin which induces misshapen nuclei, cellular senescence, and aging. We previously showed that the phospholipase A2 receptor (PLA2R1) promotes senescence induced by replicative, oxidative, and oncogenic stress but its role during progerin-induced senescence and in progeria is currently unknown. Here, we show that knockdown of PLA2R1 prevented senescence induced by progerin expression in human fibroblasts and markedly delayed senescence of HGPS patient-derived fibroblasts. Whole-body knockout of Pla2r1 in a mouse model of progeria decreased some premature aging phenotypes, such as rib fracture and decreased bone content, together with decreased senescence marker. Progerin-expressing human fibroblasts exhibited a high frequency of misshapen nuclei and increased farnesyl diphosphate synthase (FDPS) expression compared to controls; knockdown of PLA2R1 reduced the frequency of misshapen nuclei and normalized FDPS expression. Pamidronate, a FDPS inhibitor, also reduced senescence and misshapen nuclei. Downstream of PLA2R1, we found that p53 mediated the progerin-induced increase in FDPS expression and in misshapen nuclei. These results suggest that PLA2R1 mediates key premature aging phenotypes through a p53/FDPS pathway and might be a new therapeutic target.

MicroRNA-Based Drugs for Brain Tumors.

MicroRNAs (miRNAs) are key regulatory elements encoded by the genome. A single miRNA can downregulate the expression of multiple genes involved in diverse functions. Because cancer is a disease with multiple gene aberrations, developing novel approaches to identify and modulate miRNA pathways may result in a breakthrough for cancer treatment. With a special focus on glioblastoma (GBM), this review provides an up-to-date summary of miRNA biogenesis, the role of miRNA in cancer resistance, and essential tools for modulating miRNA expression, as well as of clinically promising RNAi delivery systems and how they can be adapted for therapy.