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Ricercatore t.d. art. 24 c. 3 lett. B
Dipartimento di Scienze della Vita sede ex-Biologia

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2022 - Curcumin-Based β-Diketo Ligands for Ga3+: Thermodynamic Investigation of Potential Metal-Based Drugs [Articolo su rivista]
Mari, Matteo; Carrozza, Debora; Malavasi, Gianluca; Venturi, Ettore; Avino, Giulia; Capponi, Pier Cesare; Iori, Michele; Rubagotti, Sara; Belluti, Silvia; Asti, Mattia; Ferrari, Erika

Curcumin is known for its therapeutic properties; among these, antioxidant, anti-inflammatory and anti-cancer ones stand out. Besides, curcumin metal complexes have shown widespread application in medicine and can be exploited as lead structures for developing metal-based drugs. Unfortunately, curcumin is poorly bioavailable, mainly due to its instability in physiological conditions; this weakness is tightly connected to the presence of the β-diketo moiety undergoing tautomeric equilibrium. Stability and metal-chelating ability can be tuned by modulating the electronic effects and steric hindrance close to the β-diketo moiety; in addition, formation of a metal complex shifts the tautomeric equilibrium towards the β-keto–enol form and increases stability in biological media. Among the metals used in clinical therapy, gallium nitrate has shown to have significant antitumor activity against non-Hodgkin lymphoma and bladder cancer, thus indicating that gallium-based drugs have potential for further development as antineoplastic agents with improved therapeutic activity. Curcuminoids have demonstrated high affinity for gallium(III), allowing the formation of stable positively charged M:L 1:2 β-diketonate complexes that benefit from the therapeutic activity of both the metal and the ligand. Seven new curcumin derivatives were synthesized and completely characterized. The new derivatives retain the solvent-dependent keto–enol tautomerism, with the prevalence of the diketo form in aqueous solution. Enhanced stability in simulated physiological conditions was observed in comparison to the lead compound curcumin. The presence of Ga3+ anticipates the dissociation of the enolic proton, allowing chelate complex formation, and simultaneously it shifts the tautomeric equilibrium towards the keto–enol form. A complete 1H/13C NMR and UV–Vis study was performed to define the metal-to-ligand stoichiometry ratio and the overall stability constants. In addition, we demonstrated that some of the derivatives have increased antiproliferative activity on colon cancer cells compared to curcumin and antioxidant properties. On the whole, the synthesized curcumin-based molecules may act as new gallium(III) chelators with improved stability with respect to curcumin and could open interesting perspectives for the development of novel therapeutic agents for cancer.

2022 - Histone Marks-Dependent Effect on Alternative Splicing: New Perspectives for Targeted Splicing Modulation in Cancer? [Articolo su rivista]
Imbriano, Carol; Belluti, Silvia

2021 - Alternative splicing of NF-YA promotes prostate cancer aggressiveness and represents a new molecular marker for clinical stratification of patients [Poster]
Belluti, Silvia; Semeghini, Valentina; Rigillo, Giovanna; Ronzio, Mirko; Benati, Daniela; Torricelli, Federica; REGGIANI BONETTI, Luca; Carnevale, Gianluca; Grisendi, Giulia; Ciarrocchi, Alessia; Dominici, Massimo; Recchia, Alessandra; Dolfini, Diletta; Imbriano, Carol

2021 - Alternative splicing of NF-YA promotes prostate cancer aggressiveness and represents a new molecular marker for clinical stratification of patients [Articolo su rivista]
Belluti, Silvia; Semeghini, Valentina; Rigillo, Giovanna; Ronzio, Mirko; Benati, Daniela; Torricelli, Federica; Reggiani Bonetti, Luca; Carnevale, Gianluca; Grisendi, Giulia; Ciarrocchi, Alessia; Dominici, Massimo; Recchia, Alessandra; Dolfini, Diletta; Imbriano, Carol

Approaches based on expression signatures of prostate cancer (PCa) have been proposed to predict patient outcomes and response to treatments. The transcription factor NF-Y participates to the progression from benign epithelium to both localized and metastatic PCa and is associated with aggressive transcriptional profile. The gene encoding for NF-YA, the DNA-binding subunit of NF-Y, produces two alternatively spliced transcripts, NF-YAs and NF-YAl. Bioinformatic analyses pointed at NF-YA splicing as a key transcriptional signature to discriminate between different tumor molecular subtypes. In this study, we aimed to determine the pathophysiological role of NF-YA splice variants in PCa and their association with aggressive subtypes.

2021 - Inhibitors of histone deacetylase 6 based on a novel 3-hydroxy-isoxazole zinc binding group [Articolo su rivista]
Linciano, P.; Pinzi, L.; Belluti, S.; Chianese, U.; Benedetti, R.; Moi, D.; Altucci, L.; Franchini, S.; Imbriano, C.; Sorbi, C.; Rastelli, G.

Histone deacetylase 6 (HDAC6) is an established drug target for cancer treatment. Inhibitors of HDAC6 based on a hydroxamic acid zinc binding group (ZBG) are often associated with undesirable side effects. Herein, we describe the identification of HDAC6 inhibitors based on a completely new 3-hydroxy-isoxazole ZBG. A series of derivatives decorated with different aromatic or heteroaromatic linkers, and various cap groups were synthesised and biologically tested. In vitro tests demonstrated that some compounds are able to inhibit HDAC6 with good potency, the best candidate reaching an IC50 of 700 nM. Such good potency obtained with a completely new ZBG make these compounds particularly attractive. The effect of the most active inhibitors on the acetylation levels of histone H3 and α- tubulin and their anti-proliferative activity of DU145 cells were also investigated. Docking studies were performed to evaluate the binding mode of these new derivatives and discuss structure-activity relationships.

2021 - The transcription factor NF-Y is required for satellite stem cell myogenic progression and skeletal muscle tissue repair [Poster]
Rigillo, Giovanna; Basile, Valentina; Belluti, Silvia; Imbriano, Carol

2021 - The transcription factor NF-Y participates to stem cell fate decision and regeneration in adult skeletal muscle [Articolo su rivista]
Rigillo, Giovanna; Basile, Valentina; Belluti, Silvia; Ronzio, Mirko; Sauta, Elisabetta; Ciarrocchi, Alessia; Latella, Lucia; Saclier, Marielle; Molinari, Susanna; Vallarola, Antonio; Messina, Graziella; Mantovani, Roberto; Dolfini, Diletta; Imbriano, Carol

2020 - Transcription Factors in Cancer: When Alternative Splicing Determines Opposite Cell Fates [Articolo su rivista]
Belluti, Silvia; Rigillo, Giovanna; Imbriano, Carol

Alternative splicing (AS) is a finely regulated mechanism for transcriptome and proteome diversification in eukaryotic cells. Correct balance between AS isoforms takes part in molecular mechanisms that properly define spatiotemporal and tissue specific transcriptional programs in physiological conditions. However, several diseases are associated to or even caused by AS alterations. In particular, multiple AS changes occur in cancer cells and sustain the oncogenic transcriptional program. Transcription factors (TFs) represent a key class of proteins that control gene expression by direct binding to DNA regulatory elements. AS events can generate cancer-associated TF isoforms with altered activity, leading to sustained proliferative signaling, differentiation block and apoptosis resistance, all well-known hallmarks of cancer. In this review, we focus on how AS can produce TFs isoforms with opposite transcriptional activities or antagonistic functions that severely impact on cancer biology. This summary points the attention to the relevance of the analysis of TFs splice variants in cancer, which can allow patients stratification despite the presence of interindividual genetic heterogeneity. Recurrent TFs variants that give advantage to specific cancer types not only open the opportunity to use AS transcripts as clinical biomarkers but also guide the development of new anti-cancer strategies in personalized medicine.

2019 - Potent Anti-Cancer Properties of Phthalimide-Based Curcumin Derivatives on Prostate Tumor Cells [Articolo su rivista]
Belluti, Silvia; Orteca, Giulia; Semeghini, Valentina; Rigillo, Giovanna; Parenti, Francesca; Ferrari, Erika; Imbriano, Carol

Metastatic castration-resistant prostate cancer is commonly treated with chemotherapy, whose effect is less than satisfactory. This raised the need for novel agents for the treatment of prostate cancer. In the present study, five phthalimide-based curcumin derivatives were synthesized and completely characterized to assess improved stability, pharmacodynamics, and radical scavenging ability. To investigate the potential application in anti-cancer therapy, the anti-proliferative activity of the synthesized molecules was determined on aggressive prostate tumor cells. We demonstrated that the K3F21 derivative has increased potency compared to curcumin, in terms of GI50, anti-proliferative and anti-migrating activities. K3F21 inhibits anchorage-dependent and -independent growth of prostate cancer cells by altering the expression of key genes controlling cell proliferation, such as Cylins D1, B1 and B2, and apoptosis, among which Puma, Noxa, and Bcl-2 family members. Finally, the anti-cancer activity of K3F21 was demonstrated by the analysis of cancer-associated PI3K/AKT, ERK, and p38 signaling pathways.

2019 - Switch of NF-YA splice variants in prostate cancer development and progression [Poster]
Belluti, Silvia; Semeghini, Valentina; Dolfini, Diletta; Rigillo, Giovanna; Imbriano, Carol

The pioneer transcription factor NF-Y is a heterotrimer composed by NF-YA, -YB and -YC subunits: NF-YA is the limiting subunit and harbors the DNA CCAAT-box binding domain. NF-Y is a master transcriptional regulator that ensures proper cell proliferation, controlling cell cycle, DNA replication, apoptosis and metabolism. Recent analyses pointed out that NF-Y binding site is over-represented in promoters of genes overexpressed during the progression from benign epithelium to Prostate Cancer (PC). Moreover, cell cycle regulation genes have emerged as a signature that can discriminate between metastatic and benign prostate tissues. The analysis of TCGA-RNAseq data highlighted a slight but significant increase of NF-YA levels in PC tumor vs normal tissues, particularly in high Gleason score specimens. Since the NF-YA gene encodes for two splice isoforms, NF-YAl (long) and NF-YAs (short), we generated untransformed and cancer prostate cell lines stably over-expressing NF-YA isoforms, to dissect the functional role of NF-YA in PC development and progression. Our data indicate that NF-YAl and NF-YAs could play different activities in cancer-associated processes, such as clonogenic ability, anchorage-independent growth, 3D cell growth, migration and invasion. In particular, in cancer cells NF-YAl improves invasion ability, while NF-YAs seems to enhance the proliferation of tumor spheroids. These results are consistent with increased NF-YAs/NF-YAl splice ratio observed in the progression from normal to malignant prostatectomy samples. Besides, normal prostate cell lines preferentially express the long NF-YA isoform, while an increase in NF-YAs/NF-YAl ratio can be observed in PC cell lines. These results prompt us to speculate that NF-YAl could participate to metastatization, while NF-YAs could have a major role in tumor growth and colonization. Disclosing this dualism could be crucial to better stratify PC patients and identify new specific anti-cancer treatments.

2019 - The transcription factor NF-Y is required for satellite stem cell proliferation and skeletal muscle tissue repair [Poster]
Rigillo, Giovanna; Basile, Valentina; Belluti, Silvia; Imbriano, Carol

The transcription factor NF-Y, composed by NF-YA, NF-YB and NF-YC subunits, has an important role in the regulation of cellular proliferation and differentiation in different cell types, among which muscle cells. While NF-YA, the DNA binding subunit of NF-Y, is down-regulated in the adult muscle of WT mice, its expression is observed in the mdx mouse, model for Duchenne Muscular Dystrophy, in which a massive regeneration mediated by resident muscle stem cells, namely Satellite Cells (SCs), occurs. With the aim to investigate the role of NF-YA in the SCs proliferation and differentiation, we generated and characterized a conditional knock out mouse model in which NF-YA is deleted in Pax7+ SCs by Tamoxifen induction in adult NF-YAflox/flox:Pax7CreER mice (NF-YA cKO). Cellular and molecular analysis carried out on isolated myofibers and SCs from WT and NF-YA cKO mice highlighted that NF-Y activity is important for the maintenance of SCs homeostasis. NF-YA loss depletes Pax7+ SCs pool and impairs SCs proliferation. Moreover, SCs-mediated regeneration following muscle damage induced by cardiotoxin is delayed in NF-YA cKO. The effect of NF-YA abrogation was also explored in post-natal muscle growth. Immunohistological analysis showed defects in muscle morphology and a decrease in SCs number in 3 weeks aged NF-YA cKO mice, period of major increment of muscle mass  by SCs-mediated myonuclear accretion.  The molecular mechanism underlying the impairment of SCs activity following NF-YA loss was investigated by AdenoCre-induced NF-YA deletion in ex vivo cultured SCs.   Overall, our results highlight a role of NF-Y in muscle regeneration and in SCs fate, whose modulation could be useful to improve stem cell based therapies to treat muscular dystrophies.

2019 - The 1,10-phenanthroline ligand enhances the antiproliferative activity of dna-intercalating thiourea-pd(Ii) and-pt(ii) complexes against cisplatin-sensitive and-resistant human ovarian cancer cell lines [Articolo su rivista]
Marverti, G.; Gozzi, G.; Lauriola, A.; Ponterini, G.; Belluti, S.; Imbriano, C.; Costi, M. P.; D’Arca, D.

Ovarian cancer is the most lethal gynecological malignancy, often because of the frequent insurgence of chemoresistance to the drugs currently used. Thus, new therapeutical agents are needed. We tested the toxicity of 16 new DNA-intercalating agents to cisplatin (cDDP)-sensitive human ovarian carcinoma cell lines and their resistant counterparts. The compounds were the complexes of Pt(II) or Pd(II) with bipyridyl (bipy) and phenanthrolyl (phen) and with four dierent thiourea ancillary ligands. Within each of the four series of complexes characterized by the same thiourea ligand, the Pd(phen) drugs invariably showed the highest anti-proliferative ecacy. This paralleled both a higher intracellular drug accumulation and a more ecient DNA intercalation than all the other metal-bidentate ligand combinations. The consequent inhibition of topoisomerase II activity led to the greatest inhibition of DNA metabolism, evidenced by the inhibition of the expression of the folate cycle enzymes and a marked perturbation of cell-cycle distribution in both cell lines. These findings indicate that the particular interaction of Pd(II) with phenanthroline confers the best pharmacokinetic and pharmacodynamic properties that make this class of DNA intercalators remarkable inhibitors, even of the resistant cell growth.

2018 - An autoregulatory loop controls the expression of the transcription factor NF-Y [Articolo su rivista]
Belluti, Silvia; Semeghini, Valentina; Basile, Valentina; Rigillo, Giovanna; Salsi, Valentina; Genovese, Filippo; Dolfini, Diletta; Imbriano, Carol

The heterotrimeric NF-Y complex is a pioneer factor that binds to CCAAT-genes and regulates their transcription. NF-Y cooperates with multiple transcription factors and co-regulators in order to positively or negatively influence gene transcription. The recruitment of NF-Y to CCAAT box is significantly enriched in cancer-associated gene promoters loci and positively correlates with malignancy. NF-Y subunits, in particular the DNA-binding subunit NF-YA and the histone-fold subunit NF-YC, appear overexpressed in specific types of cancer. Here we demonstrate that NF-Y subunits expression is finely regulated through transcriptional and post-translational mechanisms thus allowing control over basal expression levels. NF-Y negatively regulates the transcription of the genes encoding for its subunits. DNA pull-down/affinity purification assay coupled with Mass Spectrometry identified putative co-regulators, such as Lamin A, involved in NF-YA gene transcription level. We also evidentiate how the stability of the complex is severely affected by the absence of one subunit. Our results identified for the first time one of the mechanisms responsible for NF-Y expression, which may be involved in the aberrant expression and activity observed in tumor cells and other pathological conditions.

2016 - Direct non transcriptional role of NF-Y in DNA replication [Articolo su rivista]
Benatti, Paolo; Belluti, Silvia; Miotto, Benoit; Neusiedler, Julia; Dolfini, Diletta; Drac, Marjorie; Basile, Valentina; Schwob, Ethienne; Mantovani, Roberto; Blow J., Julian; Imbriano, Carol

NF-Y is a heterotrimeric transcription factor, which plays a pioneer role in the transcriptional control of promoters containing the CCAAT-box, among which genes involved in cell cycle regulation, apoptosis and DNA damage response. The knock-down of the sequence-specific subunit NF-YA triggers defects in S-phase progression, which lead to apoptotic cell death. Here, we report that NF-Y has a critical function in DNA replication progression, independent from its transcriptional activity. NF-YA colocalizes with early DNA replication factories, its depletion affects the loading of replisome proteins to DNA, among which Cdc45, and delays the passage from early to middle-late S phase. Molecular combing experiments are consistent with a role for NF-Y in the control of fork progression. Finally, we unambiguously demonstrate a direct non-transcriptional role of NF-Y in the overall efficiency of DNA replication, specifically in the DNA elongation process, using a Xenopus cell-free system. Our findings broaden the activity of NF-Y on a DNA metabolism other than transcription, supporting the existence of specific TFs required for proper and efficient DNA replication.

2016 - Direct non transcriptional role of the CCAAT-factor NF-Y in DNA replication [Poster]
Belluti, Silvia; Benatti, Paolo; Benoit, Miotto; Julia, Neusiedler; Diletta, Dolfini; Marjorie, Drac; Etienne, Schwob; Roberto, Mantovani; Julian Blow, J.; Imbriano, Carol

The heterotrimeric transcription factor NF-Y plays a pioneer role in the transcriptional control of promoters containing the CCAAT-box, among which genes involved in cell cycle regulation. The expression levels of the sequence specific subunit NF-YA increase at the onset of S phase, and NF-YA loss in primary and tumor mammalian cells triggers defects in S-phase progression. Here, we show that NF-Y has a critical function in DNA replication progression, independent from its transcriptional activity. NF-YA colocalizes with early DNA replication factories, its depletion affects the loading of replisome proteins to DNA and delays the passage from early to middle-late S phase. Molecular combing experiments are consistent with a role for NF-Y in the control of fork progression. Using a Xenopus cell-free system, we unambiguously demonstrate a direct non-transcriptional role of NF-Y in the overall efficiency of DNA replication. Spontaneous DNA damage occurs in NF-YA-deficient cells, while NF-YA overexpression reduces the sensitivity to replication stress, suggesting a role for NF-Y in replication stress response and genome maintenance. Our findings broaden the activity of NF-Y on a DNA metabolism other than transcription, supporting the existence of specific transcription factors required for proper and efficient DNA replication.

2016 - NF-Y loss triggers p53 stabilization and apoptosis in HPV18-positive cells by affecting E6 transcription [Articolo su rivista]
Benatti, Paolo; Basile, Valentina; Dolfini, Diletta; Belluti, Silvia; Tomei, Margherita; Imbriano, Carol

The expression of the high risk HPV18 E6 and E7 oncogenic proteins induces the transformation of epithelial cells, through the disruption of p53 and Rb function. The binding of cellular transcription factors to cis-regulatory elements in the viral Upstream Regulatory Region (URR) stimulates E6/E7 transcription. Here, we demonstrate that the CCAAT-transcription factor NF-Y binds to a non-canonical motif within the URR and activates viral gene expression. In addition, NF-Y indirectly up-regulates HPV18 transcription through the transactivation of multiple cellular transcription factors. NFYA depletion inhibits the expression of E6 and E7 genes and re-establishes functional p53. The activation of p53 target genes in turn leads to apoptotic cell death. Finally, we show that NF-YA loss sensitizes HPV18-positive cells toward the DNA damaging agent Doxorubicin, via p53-mediated transcriptional response.

2016 - NF-YA splice variants have different roles on muscle differentiation [Articolo su rivista]
Basile, Valentina; Baruffaldi, Fiorenza; Dolfini, Diletta; Belluti, Silvia; Benatti, Paolo; Ricci, Laura; Artusi, Valentina; Tagliafico, Enrico; Mantovani, Roberto; Molinari, Susanna; Imbriano, Carol

The heterotrimeric CCAAT-binding factor NF-Y controls the expression of a multitude of genes involved in cell cycle progression. NF-YA is present in two alternatively spliced isoforms, NF-YAs and NF-YAl, differing in 28 aminoacids in the N-terminal Q-rich activation domain. NF-YAs has been identified as a regulator of stemness and proliferation in mouse embryonic cells (mESCs) and human hematopoietic stem cells (hHSCs), whereas the role of NF-YAl is not clear. In the muscle system, NF-YA expression is observed in proliferating cells, but barely detectable in terminally differentiated cells in vitro and adult skeletal muscle in vivo. Here, we show that NF-YA inactivation in mouse myoblasts impairs both proliferation and differentiation. The overexpression of the two NF-YA isoforms differentially affects myoblasts fate: NF-YAs enhance cell proliferation, while NF-YAl boosts differentiation. The molecular mechanisms were investigated by expression profilings, detailing the opposite programs of the two isoforms. Bioinformatic analysis of the regulated promoters failed to detect a significant presence of CCAAT boxes in the regulated genes. NF-YAl activates directly Mef2D, Six genes, and p57kip2 (Cdkn1c), and indirectly the myogenic regulatory factors (MRFs). Specifically, Cdkn1c activation is induced by NF-Y binding to its CCAAT promoter and by reducing the expression of the lncRNA Kcnq1ot1, a negative regulator of Cdkn1c transcription. Overall, our results indicate that NF-YA alternative splicing is an influential muscle cell determinant, through direct regulation of selected cell cycle blocking genes, and, directly and indirectly, of muscle-specific transcription factors.

2013 - A non transcriptional role for NF-Y in DNA replication [Poster]
Benatti, Paolo; Belluti, Silvia; Neusiedler, Julia; Basile, Valentina; Blow, J. Julian; Imbriano, Carol

The heterotrimeric transcription factor NF-Y, composed by NF-YA, NF-YB and NF-YC subunits, is a key transcriptional regulator of cell cycle progression. Using data generated by ENCODE, we identified a striking overlap between loci bound by NF-Y-and ORC2, hinting at a possible role of NF-Y in DNA replication. NF-YA knock-down leads to replication defects and the activation an intra-S checkpoint. We investigated the role of NF-Y in DNA replication by using the Xenopus cell-free system. NF-Y subunits were found to be recruited to chromatin during DNA replication. Both immunodepletion of NF-YA or NF-YB and overexpression of a dominant-negative NF-YA mutant lead to a clear decrease in DNA synthesis. In mammalian cells, NF-Y colocalizes and directly interacts with DNA replication proteins. Nascent strand abundance assay in NF-YA inactivated cells corroborates that NF-Y participates to the DNA replication process. Our data highlight that, in addition to its transcriptional activity in controlling cell proliferation, NF-Y plays a key role in the non transcriptional control of DNA replication.

2013 - A specific role for the splice variants of the transcription factor NF-Y in modulating the transcriptional activity of the myogenic program [Poster]
Basile, Valentina; Baruffaldi, Fiorenza; Belluti, Silvia; Benatti, Paolo; Mantovani, Roberto; Molinari, Susanna; Imbriano, Carol

Cell proliferation and differentiation programs are highly regulated transcriptional processes essential for myogenesis. The transcription factor NF-Y has been long considered a fundamental player of cell growth by supporting the basal transcription of various cell cycle genes. It is composed by the NF-YB/NF-YC heterodimer and NF-YA, which interacts with the other two subunits and confers the strict sequence specificity to the complex. The NF-YA gene encodes two alternatively splice transcripts (NF-YAs and NF-YAl), which differently regulate cell proliferation and differentiation, as shown in haematopoietic and mouse embryonic stem cells. NF-YAl expression is down-regulated in terminally differentiated muscle cells and in skeletal and cardiac muscle tissues. Its forced expression in muscle cells committed to differentiate impairs their exit from the cell cycle and indirectly interferes with the differentiation program. Here we show that the two NF-YA isoforms play a different role in the transcriptional activity of the myogenic program and may regulate the activity of muscle satellite cells.

2013 - bis-Dehydroxy-Curcumin Triggers Mitochondrial-Associated Cell Death in Human Colon Cancer Cells through ER-Stress Induced Autophagy. [Articolo su rivista]
Basile, Valentina; Belluti, Silvia; Ferrari, Erika; Gozzoli, C; Ganassi, Sonia; Quaglino, Daniela; Saladini, Monica; Imbriano, Carol

Background: The activation of autophagy has been extensively described as a pro-survival strategy, which helps to keep cells alive following deprivation of nutrients/growth factors and other stressful cellular conditions. In addition to cytoprotective effects, autophagy can accompany cell death. Autophagic vacuoles can be observed before or during cell death, but the role of autophagy in the death process is still controversial. A complex interplay between autophagy and apoptosis has come to light, taking into account that numerous genes, such as p53 and Bcl-2 family members, are shared between these two pathways. Methodology/Principal Findings: In this study we showed a potent and irreversible cytotoxic activity of the stable Curcumin derivative bis-DeHydroxyCurcumin (bDHC) on human colon cancer cells, but not on human normal cells. Autophagy is elicited by bDHC before cell death as demonstrated by increased autophagosome formation -measured by electron microscopy, fluorescent LC3 puncta and LC3 lipidation- and autophagic flux -measured by interfering LC3-II turnover. The accumulation of poly-ubiquitinated proteins and ER-stress occurred upstream of autophagy induction and resulted in cell death. Cell cycle and Western blot analyses highlighted the activation of a mitochondrial-dependent apoptosis, which involves caspase 7, 8, 9 and Cytochrome C release. Using pharmacological inhibitions and RNAi experiments, we showed that ER-stress induced autophagy has a major role in triggering bDHC-cell death. Conclusion/Significance: Our findings describe the mechanism through which bDHC promotes tumor selective inhibition of proliferation, providing unequivocal evidence of the role of autophagy in contrasting the proliferation of colon cancer cells.

2013 - Concurrent inhibition of enzymatic activity and NF-Y-mediated transcription of Topoisomerase-IIα by bis-DemethoxyCurcumin in cancer cells [Articolo su rivista]
Belluti, Silvia; Basile, Valentina; Benatti, Paolo; Ferrari, Erika; Marverti, Gaetano; Imbriano, Carol

Topoisomerase-IIa (TOP2A) enzyme is essential for cell viability due to its fundamental role in DNA metabolism and in chromatin organization during interphase and mitosis. TOP2A expression is finely regulated at the transcriptional level through the binding of the CCAAT-transcription factor NF-Y to its promoter. Overexpression and/or amplification of TOP2A have been observed in many types of cancers. For this reason, TOP2A is the target of the most widely successful drugs in cancer chemotherapy, such as TOP2A poisons, which stabilize TOP2A-DNA cleavage complexes and create DSBs, leading to chromosome damage and cell death. We previously reported that the Curcumin-derivative bis-DemethoxyCurcumin (bDMC) is an anti-proliferative agent that inhibits cell growth by concomitant G1/S and G2/M arrest. Here we showed that bDMC irreversibly induces DSBs in cancer cells, but not in normal cells, by targeting TOP2A activity and expression. TOP2A ablation by siRNA corroborates its contribution to apoptosis induced by bDMC. Short-term exposure to bDMC induces retention of TOP2A-DNA intermediates, while longer exposure inhibits TOP2A transcription by affecting expression and sub-cellular localization of NF-Y subunits. ChIP analysis highlighted reduced recruitment of NF-Y to TOP2A regulatory regions, concomitantly to histone deacetylation and decreased gene transcription. Our findings suggest that the dual activity of bDMC on TOP2A represents a novel therapeutic strategy to induce persistent apoptosis in cancer cells and identify NF-Y regulation as a promising approach in anti-cancer therapy.

2009 - Curcumin derivatives: molecular basis of their anti-cancer activity. [Articolo su rivista]
Basile, Valentina; Ferrari, Erika; Lazzari, Sandra; Belluti, S.; Pignedoli, Francesca; Imbriano, Carol

Curcumin, a phenolic compound from the plant Curcuma longa L., has shown a wide-spectrum of chemopreventive, anti-oxidant and anti-tumor properties. Although its promising chemotherapeutic activity, preclinical and clinical studies highlight Curcumin limited therapeutic application due to its instability in physiological conditions. To improve its stability and activity, many derivatives have been synthesized and studied, among which bis-DemethoxyCurcumin (bDMC) and diAcetylCurcumin (DAC). In this report, we show that both bDMC and DAC are more stable than Curcumin in physiological medium. To explore the mechanism of their chemotherapeutic effect, we studied their role in proliferation in the HCT116 human colon cancer cells. We correlated kinetic stability and cellular uptake data to their biological effects. Both bDMC and DAC impair correct spindles formation and induce a p53- and p21(CIP1/WAF1)- independent mitotic arrest, which is more stable and long-lasting for bDMC. A subsequent p53/p21(CIP1/WAF1)- dependent inhibition of G1 to S transition is triggered by Curcumin and DAC as a consequence of the mitotic slippage, preventing postmitotic cells from re-entering the cell cycle. Conversely, the G1/S arrest induced by bDMC is a direct effect of the drug and concomitant to the mitotic block. Finally, we demonstrate that bDMC induces rapid DNA double-strand breaks, moving for its possible development in anti-cancer clinical applications.

2009 - Understanding the molecular mechanisms of Curcumin derivatives chemotherapic activity [Relazione in Atti di Convegno]
Basile, Valentina; Ferrari, Erika; Lazzari, Sandra; Belluti, Silvia; Pignedoli, Francesca; Imbriano, Carol