RESUMO
Malignant mesothelioma (MM) is a rare orphan aggressive neoplasia with low survival rates. Among the other signaling pathways, ErbB receptors and Hh signaling are deregulated in MM. Thus, molecules involved in these signaling pathways could be used for targeted therapy approaches. The aim of this study was to evaluate the effects of inhibitors of Hh- (GANT-61) and ErbB receptors (Afatinib)-mediated signaling pathways, when used alone or in combination, on growth, cell cycle, cell death and autophagy, modulation of molecules involved in transduction pathways, in three human MM cell lines of different histotypes. The efficacy of the combined treatment was also evaluated in a murine epithelioid MM cell line both in vitro and in vivo. This study demonstrated that combined treatment with two inhibitors counteracting the activation of two different signaling pathways involved in neoplastic transformation and progression, such as those activated by ErbB and Hh signaling, is more effective than the single treatments in reducing MM growth in vitro and in vivo. This study may have clinical implications for the development of targeted therapy approaches for MM.
Assuntos
Receptores ErbB , Mesotelioma Maligno , Animais , Linhagem Celular Tumoral , Receptores ErbB/metabolismo , Proteínas Hedgehog , Humanos , Camundongos , Transdução de Sinais , Proteína GLI1 em Dedos de ZincoRESUMO
AIMS: Inherited or somatic mutations in the MRE11, RAD50 and NBN genes increase the incidence of tumours, including medulloblastoma (MB). On the other hand, MRE11, RAD50 and NBS1 protein components of the MRN complex are often overexpressed and sometimes essential in cancer. In order to solve the apparent conundrum about the oncosuppressive or oncopromoting role of the MRN complex, we explored the functions of NBS1 in an MB-prone animal model. MATERIALS AND METHODS: We generated and analysed the monoallelic or biallelic deletion of the Nbn gene in the context of the SmoA1 transgenic mouse, a Sonic Hedgehog (SHH)-dependent MB-prone animal model. We used normal and tumour tissues from these animal models, primary granule cell progenitors (GCPs) from genetically modified animals and NBS1-depleted primary MB cells, to uncover the effects of NBS1 depletion by RNA-Seq, by biochemical characterisation of the SHH pathway and the DNA damage response (DDR) as well as on the growth and clonogenic properties of GCPs. RESULTS: We found that monoallelic Nbn deletion increases SmoA1-dependent MB incidence. In addition to a defective DDR, Nbn+/- GCPs show increased clonogenicity compared to Nbn+/+ GCPs, dependent on an enhanced Notch signalling. In contrast, full NbnKO impairs MB development both in SmoA1 mice and in an SHH-driven tumour allograft. CONCLUSIONS: Our study indicates that Nbn is haploinsufficient for SHH-MB development whereas full NbnKO is epistatic on SHH-driven MB development, thus revealing a gene dosage-dependent effect of Nbn inactivation on SHH-MB development.
Assuntos
Proteínas de Ciclo Celular , Neoplasias Cerebelares , Proteínas de Ligação a DNA , Meduloblastoma , Animais , Proteínas de Ciclo Celular/genética , Neoplasias Cerebelares/genética , Neoplasias Cerebelares/patologia , Proteínas de Ligação a DNA/genética , Dosagem de Genes , Genes Essenciais , Proteínas Hedgehog/genética , Proteínas Hedgehog/metabolismo , Meduloblastoma/genética , Meduloblastoma/patologia , Camundongos , Camundongos TransgênicosRESUMO
Vehicular trauma is the most common cause of pelvic fractures. In motorcycle collisions, the driver strikes or is struck by a fixed object, and is subjected to blunt trauma and deceleration forces. Injuries around the scrotum and perineum of victims in motorcycle accidents are known as a fuel tank injuries (FTI). We report the case of a 26-year-old male motorcyclist involved in a fatal high-speed head-on collision with a car. At autopsy, purple bruising distributed symmetrically over both hips with scrotal lacerations were found. Partial bowel evisceration through an abdominal lacerated wound, extensive abdominal organ injuries and multiple fractures were also found. Considering the dynamics of the accident and the type of motorcycle he had been riding, the pelvic bruising and the scrotal injury were related to violent deceleration following the impact, leading the driver to slide forward against the fuel tank of the motorcycle.FTI is comparatively rare in motorcycle accidents because it only occurs in cases involving a head-on collision, and most drivers try to swerve or correct their direction just prior to the collision. Nevertheless, the most frequent cause of pelvic injuries in motorcyclists is caused by contact with the vehicles fuel tank during the crash. Forensic pathologists should have a better knowledge of FTIs as they are helpful in understand the dynamics of the accident and in distinguishing the driver from the passenger in two-rider motorcycle crashes.
Assuntos
Traumatismos Abdominais , Contusões , Fraturas Ósseas , Lacerações , Ferimentos e Lesões , Masculino , Humanos , Adulto , Motocicletas , Acidentes de Trânsito , Escroto/lesõesRESUMO
The human family of Potassium (K+) Channel Tetramerization Domain (KCTD) proteins counts 25 members, and a significant number of them are still only partially characterized. While some of the KCTDs have been linked to neurological disorders or obesity, a growing tally of KCTDs are being associated with cancer hallmarks or involved in the modulation of specific oncogenic pathways. Indeed, the potential relevance of the variegate KCTD family in cancer warrants an updated picture of the current knowledge and highlights the need for further research on KCTD members as either putative therapeutic targets, or diagnostic/prognostic markers. Homology between family members, capability to participate in ubiquitination and degradation of different protein targets, ability to heterodimerize between members, role played in the main signalling pathways involved in development and cancer, are all factors that need to be considered in the search for new key players in tumorigenesis. In this review we summarize the recent published evidence on KCTD members' involvement in cancer. Furthermore, by integrating this information with data extrapolated from public databases that suggest new potential associations with cancers, we hypothesize that the number of KCTD family members involved in tumorigenesis (either as positive or negative modulator) may be bigger than so far demonstrated. Video abstract.
Assuntos
Neoplasias/metabolismo , Canais de Potássio de Abertura Dependente da Tensão da Membrana/metabolismo , Animais , Carcinogênese/metabolismo , Carcinogênese/patologia , Genes Supressores de Tumor , Humanos , Neoplasias/patologia , Degeneração Neural/metabolismo , Degeneração Neural/patologia , Oncogenes , Canais de Potássio de Abertura Dependente da Tensão da Membrana/genéticaRESUMO
PURPOSE OF REVIEW: This review was designed to revaluate the androgen role on the mechanisms of hypertension and cardiovascular risks in both men and women. Sex steroids are involved in the regulation of blood pressure, but pathophysiological mechanism is not well understood. Androgens have an important effect on metabolism, adipose and endothelial cell function, and cardiovascular risk in both men and women. A focal point in this contest is represented by the possible gender-specific regulation of different tissues and in particular of the adipose cell. Available data confirm that androgen deficiency is linked to increased prevalence of hypertension and cardiovascular diseases. Adipocyte dysfunction seems to be the main involved mechanism. Androgen replacement reduces inflammation state in man, protecting by metabolic syndrome progression. In women, androgen excess has been considered as promoting factor of cardiovascular risk. However, recent data suggest that excessive androgen production has little effect per se in inducing hypertension in young women of reproductive age. Also in postmenopausal women, data on relative androgen excess and hypertension are missing, while adrenal androgen deficiency has been associated to increased mortality. RECENT FINDINGS: Molecular mechanisms linking androgen dysregulation to hypertension are almost Unknown, but they seem to be related to increased visceral fat, promoting a chronic inflammatory state through different mechanisms. One of these may involve the recruitment and over-activation of NF-kB, a ubiquitous transcription factor also expressed in adipose cells, where it may cause the production of cytokines and other immune factors. The NF-kB signalling pathway may also influence brown adipogenesis leading to the preferential enlargement of visceral adipocytes. Chronic inflammation and adipocyte dysfunction may alter endothelial function leading to hypertension. Both in men and in women, particularly in the post-menopausal period, hypoandrogenism seems to be a major determinant of the increased prevalence of hypertension. The relationship between androgen signalling and NF-kB might explain the pathophysiological mechanism leading to the development of endothelium dysfunction and hypertension.
Assuntos
Androgênios , Hormônios Esteroides Gonadais , Hipertensão/fisiopatologia , Síndrome Metabólica/fisiopatologia , Obesidade/fisiopatologia , Síndrome do Ovário Policístico/fisiopatologia , Doenças Cardiovasculares/etiologia , Doenças Cardiovasculares/fisiopatologia , Feminino , Humanos , Masculino , Pós-Menopausa , Fatores de Risco , Fatores SexuaisRESUMO
"Background/Aim": the current inability to diagnose Pancreatic Cancer Adenocarcinoma (PDAC) at an early stage strongly influences therapeutic strategies. Protein Induced by Vitamin K Absence (PIVKA II) showed an accurate diagnostic performance for PDAC. Since circulating PIVKA II has been recently associated with pancreatic origin cells with Vimentin, an epithelial-to-mesenchymal transition (EMT) early activation marker, the aim of this study was to investigate in vivo the combination between the two proteins. "Materials and Methods": we assayed the presence of PIVKA II and Vimentin proteins by using different diagnostic methods. A total of 20 PDAC patients and 10 healthy donors were tested by Western Blot analysis; 74 PDAC patient and 46 healthy donors were assayed by ECLIA and Elisa. "Results": Western Blot analysis showed the concomitant expression of PIVKA II and Vimentin in PDAC patient sera. Immunometric assay performed on a larger cohort of patients demonstrated that 72% of PIVKA II-positive PDAC patients were Vimentin-positive. Additionally, in a group of PDAC patients with PIVKA II levels ≥2070 ng/mL, the percentage of Vimentin-positive subjects reached 84%. "Conclusion": the association between PIVKA II protein and the EMT suggests that this molecule could be considered a marker of the acquisition of an aggressive phenotype.
RESUMO
The Sonic Hedgehog (SHH) pathway is crucial regulator of embryonic development and stemness. Its alteration leads to medulloblastoma (MB), the most common malignant pediatric brain tumor. The SHH-MB subgroup is the best genetically characterized, however the molecular mechanisms responsible for its pathogenesis are not fully understood and therapeutic benefits are still limited. Here, we show that the pro-oncogenic stemness regulator Spalt-like transcriptional factor 4 (SALL4) is re-expressed in mouse SHH-MB models, and its high levels correlate with worse overall survival in SHH-MB patients. Proteomic analysis revealed that SALL4 interacts with REN/KCTD11 (here REN), a substrate receptor subunit of the Cullin3-RING ubiquitin ligase complex (CRL3REN) and a tumor suppressor lost in ~30% of human SHH-MBs. We demonstrate that CRL3REN induces polyubiquitylation and degradation of wild type SALL4, but not of a SALL4 mutant lacking zinc finger cluster 1 domain (ΔZFC1). Interestingly, SALL4 binds GLI1 and cooperates with HDAC1 to potentiate GLI1 deacetylation and transcriptional activity. Notably, inhibition of SALL4 suppresses SHH-MB growth both in murine and patient-derived xenograft models. Our findings identify SALL4 as a CRL3REN substrate and a promising therapeutic target in SHH-dependent cancers.
Assuntos
Neoplasias Encefálicas , Neoplasias Cerebelares , Meduloblastoma , Animais , Humanos , Camundongos , Proteínas de Ciclo Celular , Neoplasias Cerebelares/genética , Neoplasias Cerebelares/patologia , Proteínas Hedgehog/metabolismo , Meduloblastoma/genética , Proteômica , Fatores de Transcrição/genética , Transferases , Proteína GLI1 em Dedos de Zinco/genéticaRESUMO
Development of the cerebellum is characterized by rapid proliferation of cerebellar granule cell precursors (GCPs) induced by paracrine stimulation of Sonic hedgehog (Shh) signaling from Purkinje cells, in the external granular layer (EGL). Then, granule cell precursors differentiate and migrate into the inner granular layer (IGL) of the cerebellum to form a terminally differentiated cell compartment. Aberrant activation of Sonic hedgehog signaling leads to granule cell precursors hyperproliferation and the onset of Sonic hedgehog medulloblastoma (MB), the most common embryonal brain tumor. ß-arrestin1 (ARRB1) protein plays an important role downstream of Smoothened, a component of the Sonic hedgehog pathway. In the medulloblastoma context, ß-arrestin1 is involved in a regulatory axis in association with the acetyltransferase P300, leading to the acetylated form of the transcription factor E2F1 (E2F1-ac) and redirecting its activity toward pro-apoptotic gene targets. This axis in the granule cell precursors physiological context has not been investigated yet. In this study, we demonstrate that ß-arrestin1 has antiproliferative and pro-apoptotic functions in cerebellar development. ß-arrestin1 silencing increases proliferation of Sonic hedgehog treated-cerebellar precursor cells while decreases the transcription of E2F1-ac pro-apoptotic targets genes, thus impairing apoptosis. Indeed, chromatin immunoprecipitation experiments show a direct interaction between ß-arrestin1 and the promoter regions of the pro-apoptotic E2F1 target gene and P27, indicating the double role of ß-arrestin1 in controlling apoptosis and cell cycle exit in a physiological context. Our data elucidate the role of ß-arrestin1 in the early postnatal stages of cerebellar development, in those cell compartments that give rise to medulloblastoma. This series of experiments suggests that the physiological function of ß-arrestin1 in neuronal progenitors is to directly control, cooperating with E2F1 acetylated form, transcription of pro-apoptotic genes.
RESUMO
Mast cells (MCs) are multifaceted innate immune cells often present in the tumor microenvironment (TME). Several recent findings support their contribution to the transition from chronic inflammation to cancer. However, MC-derived mediators can either favor tumor progression, inducing the spread of the tumor, or exert anti-tumorigenic functions, limiting tumor growth. This apparent controversial role likely depends on the plastic nature of MCs that under different microenvironmental stimuli can rapidly change their phenotype and functions. Thus, the exact effect of unique MC subset(s) during tumor progression is far from being understood. Using a murine model of colitis-associated colorectal cancer, we initially characterized the MC population within the TME and in non-lesional colonic areas, by multicolor flow cytometry and confocal microscopy. Our results demonstrated that tumor-associated MCs harbor a main connective tissue phenotype and release high amounts of Interleukin (IL)-6 and Tumor Necrosis Factor (TNF)-α. This MC phenotype correlates with the presence of high levels of Stem Cell Factor (SCF) and IL-33 inside the tumor. Thus, we investigated the effect of SCF and IL-33 on primary MC cultures and underscored their ability to shape MC phenotype eliciting the production of pro-inflammatory cytokines. Our findings support the conclusion that during colonic transformation a sustained stimulation by SCF and IL-33 promotes the accumulation of a prevalent connective tissue-like MC subset that through the secretion of IL-6 and TNF-α maintains a pro-inflammatory microenvironment.
Assuntos
Interleucina-33 , Fator de Células-Tronco , Animais , Camundongos , Citocinas , Interleucina-33/genética , Interleucina-6 , Mastócitos , Fenótipo , Fator de Necrose Tumoral alfa/farmacologiaRESUMO
Contrasting evidence is present regarding the contribution of stem/progenitor cell populations to pancreatic regeneration in diabetes. Interestingly, a cell compartment with stem/progenitor cell features has been identified in the pancreatic duct glands (PDGs). The aims of the present study were to evaluate pancreatic islet injury and regeneration, and the participation of the PDG compartment in type 2 diabetic mellitus (T2DM) and in an experimental model of diabetes. Human pancreata were obtained from normal (N = 5) or T2DM (N = 10) cadaveric organ donors. Experimental diabetes was generated in mice by intraperitoneal injection of 150 mg/kg of streptozotocin (STZ, N = 10); N = 10 STZ mice also received daily intraperitoneal injections of 100 µg of human recombinant PDX1 peptide (STZ + PDX1). Samples were examined by immunohistochemistry/immunofluorescence or RT-qPCR. Serum glucose and c-peptide levels were measured in mice. Islets in T2DM patients showed ß-cell loss, signs of injury and proliferation, and a higher proportion of central islets. PDGs in T2DM patients had a higher percentage of proliferating and insulin+ or glucagon+ cells compared to controls; pancreatic islets could be observed within pancreatic duct walls of T2DM patients. STZ mice were characterized by reduced islet area compared to controls. PDX1 treatment increased islet area and the percentage of central islets compared to untreated STZ mice but did not revert diabetes. In conclusion, T2DM patients show signs of pancreatic islet regeneration and involvement of the PDG niche. PDX1 administration could support increased endocrine pancreatic regeneration in STZ. These findings contribute to defining the role and participation of stem/progenitor cell compartments within the pancreas.
RESUMO
Target gene silencing is a strategy that can be used to turn off pathways or genes which are difficult to turn off pharmacologically, both because of lack of targeting drugs, or because of the risk of wider off-target effects. Here we describe the design and use of short hairpin RNA (ShRNA) and lentiviral vectors as an efficient technique for silencing NF-kappaB (NF-κB) pathway in cultured cells. This method can be used also in hard to transfect primary cell cultures.
Assuntos
RNA Interferente Pequeno/genética , Inativação Gênica , Vetores Genéticos/genética , Lentivirus/genética , Lentivirus/metabolismo , NF-kappa B/genética , NF-kappa B/metabolismo , Interferência de RNARESUMO
There is a lack of knowledge on the possible influence of systemic conditions on peri-implantitis. The aim of this case-control study is to evaluate the difference in terms of oral pathogens' concentrations in the peri-implant sulcus of a group of patients affected by metabolic syndrome (Mets) compared to healthy subjects. For each patient, peri-implant sulcular biofilm samples were obtained by inserting two sterile endodontic paper points in the deepest aspect of the peri-implant sulcus for 30 s. The quantitative real-time polymerase chain reaction was performed to evaluate total bacterial counts of six pathogens. Patients were screened for peri-implant diseases and clinical and radiographic parameters were recorded. A total of 50 patients was enrolled in the study, 25 affected by Mets and 25 healthy. Significantly higher bacterial counts were discovered for Aggregatibacter actinomycetemcomitans (p = 0.0008), Prevotella intermedia (p = 0.0477) and Staphylococcus aureus (p = 0.034) in MetS patients compared to healthy subjects. Performing a sub-group analysis, considering peri-implant status and dividing patients by MetS diagnosis, no statistically significant (p < 0.05) differences were found. For the first time, a correlation between MetS presence and a greater prevalence of some bacterial species in the peri-implant sulcus was reported, irrespectively from peri-implant status (health vs. disease).
RESUMO
The Hedgehog (Hh) signaling pathway plays a crucial role in normal embryonic development and adult tissue homeostasis. On the other end, dysregulated Hh signaling triggers a prolonged mitogenic response that may prompt abnormal cell proliferation, favoring tumorigenesis. Indeed, about 30% of medulloblastomas (MBs), the most common malignant childhood cerebellar tumors, exhibit improper activation of the Hh signaling. The oncosuppressor KCASH2 has been described as a suppressor of the Hh signaling pathway, and low KCASH2 expression was observed in Hh-dependent MB tumor. Therefore, the study of the modulation of KCASH2 expression may provide fundamental information for the development of new therapeutic approaches, aimed to restore physiological KCASH2 levels and Hh inhibition. To this end, we have analyzed the TATA-less KCASH2 proximal promoter and identified key transcriptional regulators of this gene: Sp1, a TF frequently overexpressed in tumors, and the tumor suppressor p53. Here, we show that in WT cells, Sp1 binds KCASH2 promoter on several putative binding sites, leading to increase in KCASH2 expression. On the other hand, p53 is involved in negative regulation of KCASH2. In this context, the balance between p53 and Sp1 expression, and the interplay between these two proteins determine whether Sp1 acts as an activator or a repressor of KCASH2 transcription. Indeed, in p53-/- MEF and p53 mutated tumor cells, we hypothesize that Sp1 drives promoter methylation through increased expression of the DNA methyltransferase 1 (DNMT1) and reduces KCASH2 transcription, which can be reversed by Sp1 inhibition or use of demethylating agents. We suggest therefore that downregulation of KCASH2 expression in tumors could be mediated by gain of Sp1 activity and epigenetic silencing events in cells where p53 functionality is lost. This work may open new venues for novel therapeutic multidrug approaches in the treatment of Hh-dependent tumors carrying p53 deficiency.
RESUMO
Both CDKN1A (p21 Waf1/Cip1) and Apoptosis signal-regulating kinase 1 (ASK1) play important roles in tumorigenesis. The role of p21 Waf1/Cip1 in attenuating ASK1-induced apoptosis by various stress conditions is well established. However, how ASK1 and p21 Waf1/Cip1 functionally interact during tumorigenesis is still unclear. To address this aspect, we crossed ASK1 knockout (ASK1KO) mice with p21 Waf1/Cip1 knockout (p21KO) mice to compare single and double-mutant mice. We observed that deletion of p21 Waf1/Cip1 leads to increased keratinocyte proliferation but also increased cell death. This is mechanistically linked to the ASK1 axis-induced apoptosis, including p38 and PARP. Indeed, deletion of ASK1 does not alter the proliferation but decreases the apoptosis of p21KO keratinocytes. To analyze as this interaction might affect skin carcinogenesis, we investigated the response of ASK1KO and p21KO mice to DMBA/TPA-induced tumorigenesis. Here we show that while endogenous ASK1 is dispensable for skin homeostasis, ASK1KO mice are resistant to DMBA/TPA-induced tumorigenesis. However, we found that epidermis lacking both p21 and ASK1 reacquires increased sensitivity to DMBA/TPA-induced tumorigenesis. We demonstrate that apoptosis and cell-cycle progression in p21KO keratinocytes are uncoupled in the absence of ASK1. These data support the model that a critical event ensuring the balance between cell death, cell-cycle arrest, and successful divisions in keratinocytes during stress conditions is the p21-dependent ASK1 inactivation.
RESUMO
MYCN drives aggressive behavior and refractoriness to chemotherapy, in several tumors. Since MYCN inactivation in clinical settings is not achievable, alternative vulnerabilities of MYCN-driven tumors need to be explored to identify more effective and less toxic therapies. We previously demonstrated that PARP inhibitors enhance MYCN-induced replication stress and promote mitotic catastrophe, counteracted by CHK1. Here, we showed that PARP and CHK1 inhibitors synergized to induce death in neuroblastoma cells and in primary cultures of SHH-dependent medulloblastoma, their combination being more effective in MYCN amplified and MYCN overexpressing cells compared to MYCN non-amplified cells. Although the MYCN amplified IMR-32 cell line carrying the p.Val2716Ala ATM mutation showed the highest sensitivity to the drug combination, this was not related to ATM status, as indicated by CRISPR/Cas9-based correction of the mutation. Suboptimal doses of the CHK1 inhibitor MK-8776 plus the PARP inhibitor olaparib led to a MYCN-dependent accumulation of DNA damage and cell death in vitro and significantly reduced the growth of four in vivo models of MYCN-driven tumors, without major toxicities. Our data highlight the combination of PARP and CHK1 inhibitors as a new potential chemo-free strategy to treat MYCN-driven tumors, which might be promptly translated into clinical trials.
Assuntos
Neoplasias Cerebelares/tratamento farmacológico , Meduloblastoma/tratamento farmacológico , Proteína Proto-Oncogênica N-Myc/genética , Neuroblastoma/tratamento farmacológico , Ftalazinas/administração & dosagem , Piperazinas/administração & dosagem , Pirazóis/administração & dosagem , Pirimidinas/administração & dosagem , Animais , Proteínas Mutadas de Ataxia Telangiectasia/genética , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Neoplasias Cerebelares/genética , Neoplasias Cerebelares/patologia , Sinergismo Farmacológico , Feminino , Amplificação de Genes/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Meduloblastoma/genética , Meduloblastoma/patologia , Camundongos , Mutação , Neuroblastoma/genética , Neuroblastoma/patologia , Ftalazinas/farmacologia , Piperazinas/farmacologia , Pirazóis/farmacologia , Pirimidinas/farmacologia , Resultado do Tratamento , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Aberrant activation of the Hedgehog (Hh) pathway leads to the development of several tumors, including medulloblastoma (MB), the most common pediatric brain malignancy. Hh inhibitors acting on GLI1, the final effector of Hh signaling, offer a valuable opportunity to overcome the pitfalls of the existing therapies to treat Hh-driven cancers. In this study, the toxicity, delivery, biodistribution, and anticancer efficacy of Glabrescione B (GlaB), a selective GLI1 inhibitor, were investigated in preclinical models of Hh-dependent MB. To overcome its poor water solubility, GlaB was formulated with a self-assembling amphiphilic polymer forming micelles, called mPEG5kDa-cholane. mPEG5kDa-cholane/GlaB showed high drug loading and stability, low cytotoxicity, and long permanence in the bloodstream. We found that mPEG5kDa-cholane efficiently enhanced the solubility of GlaB, thus avoiding the use of organic solvents. mPEG5kDa-cholane/GlaB possesses favorable pharmacokinetics and negligible toxicity. Remarkably, GlaB encapsulated in mPEG5kDa-cholane micelles was delivered through the blood-brain barrier and drastically inhibited tumor growth in both allograft and orthotopic models of Hh-dependent MB. Our findings reveal that mPEG5kDa-cholane/GlaB is a good candidate for the treatment of Hh-driven tumors and provide relevant implications for the translation of GlaB into clinical practice.
Assuntos
Neoplasias Cerebelares/tratamento farmacológico , Cromonas/administração & dosagem , Portadores de Fármacos/química , Proteínas Hedgehog/antagonistas & inibidores , Meduloblastoma/tratamento farmacológico , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Barreira Hematoencefálica/metabolismo , Linhagem Celular Tumoral , Neoplasias Cerebelares/genética , Neoplasias Cerebelares/patologia , Colanos/química , Cromonas/farmacocinética , Modelos Animais de Doenças , Composição de Medicamentos/métodos , Liberação Controlada de Fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Proteínas Hedgehog/metabolismo , Humanos , Masculino , Meduloblastoma/genética , Meduloblastoma/patologia , Camundongos , Camundongos Transgênicos , Micelas , Polietilenoglicóis/química , Cultura Primária de Células , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Distribuição TecidualRESUMO
Colorectal cancer (CRC) is a leading cause of cancer death. Chemoresistance is a pivotal feature of cancer cells leading to treatment failure and ATP-binding cassette (ABC) transporters are responsible for the efflux of several molecules, including anticancer drugs. The Hedgehog-GLI (HH-GLI) pathway is a major signalling in CRC, however its role in chemoresistance has not been fully elucidated. Here we show that the HH-GLI pathway favours resistance to 5-fluorouracil and Oxaliplatin in CRC cells. We identified potential GLI1 binding sites in the promoter region of six ABC transporters, namely ABCA2, ABCB1, ABCB4, ABCB7, ABCC2 and ABCG1. Next, we investigated the binding of GLI1 using chromatin immunoprecipitation experiments and we demonstrate that GLI1 transcriptionally regulates the identified ABC transporters. We show that chemoresistant cells express high levels of GLI1 and of the ABC transporters and that GLI1 inhibition disrupts the transporters up-regulation. Moreover, we report that human CRC tumours express high levels of the ABCG1 transporter and that its expression correlates with worse patients' prognosis. This study identifies a new mechanism where HH-GLI signalling regulates CRC chemoresistance features. Our results indicate that the inhibition of Gli1 regulates the ABC transporters expression and therefore should be considered as a therapeutic option in chemoresistant patients.
Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Neoplasias Colorretais/metabolismo , Proteínas Hedgehog/metabolismo , Proteína GLI1 em Dedos de Zinco/metabolismo , Transportadores de Cassetes de Ligação de ATP/genética , Antineoplásicos/farmacologia , Apoptose/efeitos dos fármacos , Apoptose/genética , Linhagem Celular Tumoral , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Resistencia a Medicamentos Antineoplásicos/efeitos dos fármacos , Resistencia a Medicamentos Antineoplásicos/genética , Fluoruracila/farmacologia , Regulação Neoplásica da Expressão Gênica , Proteínas Hedgehog/genética , Humanos , Estimativa de Kaplan-Meier , Proteína 2 Associada à Farmacorresistência Múltipla , Oxaliplatina/farmacologia , Regiões Promotoras Genéticas/genética , Ligação Proteica , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/genética , Proteína GLI1 em Dedos de Zinco/genéticaRESUMO
Eukaryotic Translation Initiation Factor 5A (EIF5A) is a translation factor regulated by hypusination, a unique posttranslational modification catalyzed by deoxyhypusine synthetase (DHPS) and deoxyhypusine hydroxylase (DOHH) starting from the polyamine spermidine. Emerging data are showing that hypusinated EIF5A regulates key cellular processes such as autophagy, senescence, polyamine homeostasis, energy metabolism, and plays a role in cancer. However, the effects of EIF5A inhibition in preclinical cancer models, the mechanism of action, and specific translational targets are still poorly understood. We show here that hypusinated EIF5A promotes growth of colorectal cancer (CRC) cells by directly regulating MYC biosynthesis at specific pausing motifs. Inhibition of EIF5A hypusination with the DHPS inhibitor GC7 or through lentiviral-mediated knockdown of DHPS or EIF5A reduces the growth of various CRC cells. Multiplex gene expression analysis reveals that inhibition of hypusination impairs the expression of transcripts regulated by MYC, suggesting the involvement of this oncogene in the observed effect. Indeed, we demonstrate that EIF5A regulates MYC elongation without affecting its mRNA content or protein stability, by alleviating ribosome stalling at five distinct pausing motifs in MYC CDS. Of note, we show that blockade of the hypusination axis elicits a remarkable growth inhibitory effect in preclinical models of CRC and significantly reduces the size of polyps in APCMin/+ mice, a model of human familial adenomatous polyposis (FAP). Together, these data illustrate an unprecedented mechanism, whereby the tumor-promoting properties of hypusinated EIF5A are linked to its ability to regulate MYC elongation and provide a rationale for the use of DHPS/EIF5A inhibitors in CRC therapy.
Assuntos
Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/patologia , Lisina/análogos & derivados , Fatores de Iniciação de Peptídeos/metabolismo , Proteínas Proto-Oncogênicas c-myc/metabolismo , Proteínas de Ligação a RNA/metabolismo , Polipose Adenomatosa do Colo/genética , Polipose Adenomatosa do Colo/patologia , Motivos de Aminoácidos , Sequência de Aminoácidos , Animais , Linhagem Celular Tumoral , Proliferação de Células/genética , Neoplasias Colorretais/genética , Regulação para Baixo , Perfilação da Expressão Gênica , Regulação Neoplásica da Expressão Gênica , Humanos , Lisina/metabolismo , Camundongos Nus , Fases de Leitura Aberta/genética , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/antagonistas & inibidores , Oxirredutases atuantes sobre Doadores de Grupo CH-NH/metabolismo , Fatores de Iniciação de Peptídeos/química , Peptídeos/metabolismo , Poliaminas/metabolismo , Biossíntese de Proteínas , Proteínas de Ligação a RNA/química , Fator de Iniciação de Tradução Eucariótico 5ARESUMO
The antidiabetic drug phenformin displays potent anticancer activity in different tumors, but its mechanism of action remains elusive. Using Shh medulloblastoma as model, we show here that at clinically relevant concentrations, phenformin elicits a significant therapeutic effect through a redox-dependent but complex I-independent mechanism. Phenformin inhibits mitochondrial glycerophosphate dehydrogenase (mGPD), a component of the glycerophosphate shuttle, and causes elevations of intracellular NADH content. Inhibition of mGPD mimics phenformin action and promotes an association between corepressor CtBP2 and Gli1, thereby inhibiting Hh transcriptional output and tumor growth. Because ablation of CtBP2 abrogates the therapeutic effect of phenformin in mice, these data illustrate a biguanide-mediated redox/corepressor interplay, which may represent a relevant target for tumor therapy.
Assuntos
Antineoplásicos/uso terapêutico , Proteínas Correpressoras/efeitos dos fármacos , Proteínas Hedgehog/efeitos dos fármacos , Hipoglicemiantes/uso terapêutico , Neoplasias/tratamento farmacológico , Fenformin/uso terapêutico , Animais , Antineoplásicos/farmacologia , Humanos , Hipoglicemiantes/farmacologia , Camundongos , Fenformin/farmacologiaRESUMO
: Pharmacological Hedgehog (Hh) pathway inhibition has emerged as a valuable anticancer strategy. A number of small molecules able to block the pathway at the upstream receptor Smoothened (Smo) or the downstream effector glioma-associated oncogene 1 (Gli1) has been designed and developed. In a recent study, we exploited the high versatility of the natural isoflavone scaffold for targeting the Hh signaling pathway at multiple levels showing that the simultaneous targeting of Smo and Gli1 provided synergistic Hh pathway inhibition stronger than single administration. This approach seems to effectively overcome the drug resistance, particularly at the level of Smo. Here, we combined the pharmacophores targeting Smo and Gli1 into a single and individual isoflavone, compound 22, which inhibits the Hh pathway at both upstream and downstream level. We demonstrate that this multitarget agent suppresses medulloblastoma growth in vitro and in vivo through antagonism of Smo and Gli1, which is a novel mechanism of action in Hh inhibition.