Telomere Dysfunction Is Associated with Altered {DNA} Organization in Trichoplein/Tchp/Mitostatin ({TpMs}) Depleted Cells

Abstract: Recently, we highlighted a novel role for the protein Trichoplein/TCHP/Mitostatin (TpMs), both as mitotic checkpoint regulator and guardian of chromosomal stability. TpMs-depleted cells show numerical and structural chromosome alterations that lead to genomic instability. This condition is a major driving force in malignant transformation as it allows for the cells acquiring new functional capabilities to proliferate and disseminate. Here, the effect of TpMs depletion was investigated in different TpMs-depleted cell lines by means of 3D imaging and 3D Structured illumination Microscopy. We show that TpMs depletion causes alterations in the 3D architecture of telomeres in colon cancer HCT116 cells. These findings are consistent with chromosome alterations that lead to genomic instability. Furthermore, TpMs depletion changes the spatial arrangement of chromosomes and other nuclear components. Modified nuclear architecture and organization potentially induce variations that precede the onset of genomic instability and are considered as markers of malignant transformation. Our present observations connect the tumor suppression ability of TpMs with its novel functions in maintaining the proper chromosomal segregation as well as the proper telomere and nuclear architecture. Further investigations will investigate the connection between alterations in telomeres and nuclear architecture with the progression of human tumors with the aim of developing personalized therapeutic interventions

ROS, Cell Senescence, and Novel Molecular Mechanisms in Aging and Age-Related Diseases

The aging process worsens the human body functions at multiple levels, thus causing its gradual decrease to resist stress, damage, and disease. Besides changes in gene expression and metabolic control, the aging rate has been associated with the production of high levels of Reactive Oxygen Species (ROS) and/or Reactive Nitrosative Species (RNS). Specific increases of ROS level have been demonstrated as potentially critical for induction and maintenance of cell senescence process. Causal connection between ROS, aging, age-related pathologies, and cell senescence is studied intensely. Senescent cells have been proposed as a target for interventions to delay the aging and its related diseases or to improve the diseases treatment. Therapeutic interventions towards senescent cells might allow restoring the health and curing the diseases that share basal processes, rather than curing each disease in separate and symptomatic way. Here, we review observations on ROS ability of inducing cell senescence through novel mechanisms that underpin aging processes. Particular emphasis is addressed to the novel mechanisms of ROS involvement in epigenetic regulation of cell senescence and aging, with the aim to individuate specific pathways, which might promote healthy lifespan and improve aging

Designing selective Cys-ligands to unpair the binding of the Human Transcription Enhancer Associated Domain 4 (hTEAD-4) with its modulators to halt cancer cell growth

The Hippo Signalling cascade is an emerging target in tumour suppression regulation, neoplastic hypertrophy, and regenerative medicine. The pathway is activated by circulating anti-proliferative signals which leads to the phosphorylation of Yes Associated Protein (hYAP1) on Ser127/381, thus 14-3-3\u3c3 mediated cytosolic retention. Genetic alterations or exogenous factor may cause YAP nuclear migration and association to TEAD1-4 (Transcription Enhancer Associated Domain), triggering up-regulation of anti-apoptotic genes [1]. hTEAD is an enhancer that activates the nuclear transcription of genes as EMT\u2019s, EGFR and cyclins, and promotes the synthesis of survivin, tyrosine kinase HER3, and mitochondrial Bcl-xL involved in cell proliferation. TEAD binds a palmitic (palm) or myristic (myr) acids, tethered at Cys367 pocket, however its biological role is still not well known. hTEAD isoform-4 is the most represented of its family in solid tumours and its overexpression or mutation leads to cancer development and metastasis. Recent studies have considered hTEAD a promising target for anticancer drugs. Its inhibition strategy includes the disruption/prevention of YAP1:TEAD4 complex formation [2]. With the aim to develop a specific cysteine-directed inhibition strategy, we studied Cys on the protein surface and investigated their reactivity. Hence, our studies focus on characterizing the recombinant hTEAD4-ybd (aa217-434) surface though the analysis of the reactivity of its four Cys thiols (Cys310, Cys335, Cys367, Cys410), all close to YAP binding area. First, myr-Cys-367 was investigated to confirm the auto-myristoilation of the E. coli recombinant hTEAD4 through RP-chromatography on UHPLC-Orbitrap Q-Ex (ThermoFisher\u2122) by multicharged TIC deconvolution, and the total myr-TEAD was assessed around 25%. Myristate position was confirmed by FASP protein tryptic hydrolysis and tandem-MS peptide analysis. We studied hTEAD binding of a small disulphides and thiols library with different chemical properties through the exposed cysteines residues in presence of different concentration of reducing agent [3]. Top8 DDA (HCD)-MS/MS scan on the tryptic peptides suggested the ligands\u2019 high selectivity towards Cys335. Cys367 was never found conjugated, even in the non-Myr fraction, hinting the low accessibility to the lipid pocket. The number of surface reactive Cys was confirmed by a reverse-titration of the protein against increasing amount of thiophenol; excess of unreacted thiophenol was measured by HPLC-UV-ELSD (Agilent\u2122 1260), suggesting a 1:1 stoichiometry. We confirmed hTEAD-ybd ligand ratio by fluoresceine labelling with absorption and fluorescence differential spectroscopy. The ongoing work engages the screening of a larger compound library to study YAP:TEAD interaction with a ligand displacement assay of labelled TEAD to a rhodamine-tagged peptidomimetic probe to achieve structural information of the heterodimer interface and to start a hit-optimization programme. REFERENCES [1] Santucci M, Vignudelli T, et al. The Hippo Pathway and YAP/TAZ-TEAD Protein-Protein Interaction as Targets for Regenerative Medicine and Cancer Treatment. J Med Chem. 2015 Jun 25;58(12):4857-73. [2] Elisi G.M, Santucci M, et al. Repurposing of Drugs Targeting YAP-TEAD Functions. Cancers 2018, 10, 329. [3] Malpezzi G MSc Degree Thesis, Solvent exposure, and reactivity of the cysteines of Transcription Enhancer Associate Domain (TEAD), a potential anticancer target, 2021. University of Pavia \u2013 University of Modena and Reggio Emilia

Anticancer activity of green tea polyphenols in prostate gland

Numerous evidences from prevention studies in humans, support the existence of an association between green tea polyphenols consumption and a reduced cancer risk. Prostate cancer is one of the most frequently diagnosed male neoplasia in the Western countries, which is in agreement with this gland being particularly vulnerable to oxidative stress processes, often associated with tumorigenesis. Tea polyphenols have been extensively studied in cell culture and animal models where they inhibited tumor onset and progression. Prostate cancer appears a suitable target for primary prevention care, since it grows slowly, before symptoms arise, thus offering a relatively long time period for therapeutic interventions. It is, in fact, usually diagnosed in men 50-year-old or older, when even a modest delay in progression of the disease could significantly improve the patients quality of life. Although epidemiological studies have not yet yielded conclusive results on the chemopreventive and anticancer effect of tea polyphenols, there is an increasing trend to employ these substances as conservative management for patients diagnosed with less advanced prostate cancer. Here, we intend to review the most recent observations relating tea polyphenols to human prostate cancer risk, in an attempt to outline better their potential employment for preventing prostate cancer

A Peptidic Thymidylate-Synthase Inhibitor Loaded on Pegylated Liposomes Enhances the Antitumour Effect of Chemotherapy Drugs in Human Ovarian Cancer Cells

There is currently no effective long-term treatment for ovarian cancer (OC) resistant to poly-chemotherapy regimens based on platinum drugs. Preclinical and clinical studies have demonstrated a strong association between development of Pt-drug resistance and increased thymidylate synthase (hTS) expression, and the consequent cross-resistance to the hTS inhibitors 5-fluorouracil (5-FU) and raltitrexed (RTX). In the present work, we propose a new tool to combat drug resistance. We propose to treat OC cell lines, both Pt-sensitive and -resistant, with dual combinations of one of the four chemotherapeutic agents that are widely used in the clinic, and the new peptide, hTS inhibitor, [D-Gln4]LR. This binds hTS allosterically and, unlike classical inhibitors that bind at the catalytic pocket, causes cell growth inhibition without inducing hTS overexpression. The dual drug combinations showed schedule-dependent synergistic antiproliferative and apoptotic effects. We observed that the simultaneous treatment or 24h pre-treatment of OC cells with the peptide followed by either agent produced synergistic effects even in resistant cells. Similar synergistic or antagonistic effects were obtained by delivering the peptide into OC cells either by means of a commercial delivery system (SAINT-PhD) or by pH sensitive PEGylated liposomes. Relative to non-PEGylated liposomes, the latter had been previously characterized and found to allow macrophage escape, thus increasing their chance to reach the tumour tissue. The transition from the SAINT-PhD delivery system to the engineered liposomes represents an advancement towards a more drug-like delivery system and a further step towards the use of peptides for in vivo studies. Overall, the results suggest that the association of standard drugs, such as cDDP and/or 5-FU and/or RTX, with the novel peptidic TS inhibitor encapsulated into PEGylated pH-sensitive liposomes can represent a promising strategy for fighting resistance to cDDP and anti-hTS drugs

Mitostatin Is Down-Regulated in Human Prostate Cancer and Suppresses the Invasive Phenotype of Prostate Cancer Cells

MITOSTATIN, a novel putative tumor suppressor gene induced by decorin overexpression, is expressed in most normal human tissues but is markedly down-regulated in advanced stages of mammary and bladder carcinomas. Mitostatin negatively affects cell growth, induces cell death and regulates the expression and activation levels of Hsp27. In this study, we demonstrated that ectopic expression of Mitostatin in PC3, DU145, and LNCaP prostate cancer cells not only induced a significant reduction in cell growth, but also inhibited migration and invasion. Moreover, Mitostatin inhibited colony formation in soft-agar of PC3 and LNCaP cells as well as tumorigenicity of LNCaP cells in nude mice. Conversely, targeting endogenous Mitostatin by siRNA and anti-sense strategies in PC3 and DU145 prostate cancer cells enhanced the malignant phenotype in both cell lines. In agreement of these anti-oncogenic roles, we discovered that Mitostatin was absent in ∼35% (n = 124) of prostate tumor samples and its overall reduction was associated with advanced cancer stages. Collectively, our findings indicate that MITOSTATIN may acts as a tumor suppressor gene in prostate cancer and provide a novel cellular and molecular mechanism to be further exploited and deciphered in our understanding of prostate cancer progression

Trichoplein binds PCM1 and controls endothelial cell function by regulating autophagy

Autophagy is an essential cellular quality control process that has emerged as a critical one for vascular homeostasis. Here, we show that trichoplein (TCHP) links autophagy with endothelial cell (EC) function. TCHP localizes to centriolar satellites, where it binds and stabilizes PCM1. Loss of TCHP leads to delocalization and proteasome-dependent degradation of PCM1, further resulting in degradation of PCM1's binding partner GABARAP. Autophagic flux under basal conditions is impaired in THCP-depleted ECs, and SQSTM1/p62 (p62) accumulates. We further show that TCHP promotes autophagosome maturation and efficient clearance of p62 within lysosomes, without affecting their degradative capacity. Reduced TCHP and high p62 levels are detected in primary ECs from patients with coronary artery disease. This phenotype correlates with impaired EC function and can be ameliorated by NF-\u3baB inhibition. Moreover, Tchp knock-out mice accumulate of p62 in the heart and cardiac vessels correlating with reduced cardiac vascularization. Taken together, our data reveal that TCHP regulates endothelial cell function via an autophagy-mediated mechanism

The key role of Mitostatin in the maintenance of genome stability

Genomic instability is a characteristic of most cancers and it refers to an increased tendency of alterations in the genome during the life cycle of cells. The fidelity of DNA replication is highly ensured by different checkpoints; the activation of spindle checkpoints prevents cells from premature entry into mitosis, avoiding incorrect chromosome segregation and aneuploidy, a typical feature of many cancers. Mitostatin, a novel protein, endowed with tumor suppressor activity, has been reported to bind centrosomal proteins Odf2 and ninein, and its depletion causes an alteration of the anchorage of microtubules to the centrosome. Since functional defects of centrosomes are associated to mitotic failure, Mitostatin may have a key role in guarding the fidelity of mitosis in cells. Here we show that the depletion of Mitostatin in cancer cells, synchronized by aphidicolin (G1/S) block and released into nocodazole-containing medium, leads to mitotic slippage and adaptation to the spindle checkpoint (SAC) in the presence of a spindle inhibitor. Concomitantly, Mitostatin depletion promotes the early degradation of Mad2 and cyclin B1. Since the activated spindle checkpoint delays cell exit from mitosis by preventing cyclin B1 proteolysis, the cyclin B1 early degradation leads to mitotic checkpoint escape and resulting chromosome instability. In this study, we report for the first time that the depletion of Mitostatin induces an increase of numerical and structural chromosomal aberrations compared to control cells. These aberrations include aneuploidy, the formation of triradials and broken chromosomes. Taken together, our observations suggest that Mitostatin plays a critical role in guarding the fidelity of mitosis, enabling the optimal activation of the spindle checkpoint (SAC). Thus, low levels of Mitostatin found in certain human tumors may contribute to cellular transformation by promoting genomic instability