RESUMEN
PURPOSE: The mainstay of treatment for basal cell carcinoma (BCC) is surgical excision, which can result in significant associated morbidity, particularly for patients with recurrent tumors. We previously conducted a drug repositioning screen using molecular data from human BCCs and identified histone deacetylase (HDAC) inhibitors as a potential treatment for BCC. Here we conduct the first proof-of-principle study of a topical pan-HDAC inhibitor, remetinostat, in human BCC. PATIENTS AND METHODS: We conducted a phase II, open-label, single-arm, single-institution trial of a topical HDAC inhibitor. Participants with at least one BCC were recruited. All participants applied 1% remetinostat gel three times daily for 6 weeks, with measurements of tumor diameter conducted at baseline and week 8. Surgical excision of the remaining tumor was conducted at the end of the study and microscopic evaluation was performed. RESULTS: Thirty-three per-protocol tumors from 25 participants were included in the analysis. The overall response rate, defined as the proportion of tumors achieving more than 30% decrease in the longest diameter from baseline to week 8, was 69.7% [90% confidence interval (CI), 54%-82.5%]. On pathologic examination, 54.8% of tumors demonstrated complete resolution. Pharmacodynamic analysis demonstrated similar levels of acetylated histone H3 in skin tissue before and after treatment, however, phosphorylation was increased. No systemic adverse events were reported. CONCLUSIONS: The HDAC inhibitor remetinostat is a well-tolerated and effective topical treatment for reducing BCC disease burden in a clinically significant manner. This provides in-human validation of HDAC inhibitors as a therapy for BCC.
Asunto(s)
Carcinoma Basocelular , Neoplasias Cutáneas , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Humanos , Masculino , Persona de Mediana Edad , Administración Tópica , Carcinoma Basocelular/tratamiento farmacológico , Geles , Estudios Prospectivos , Neoplasias Cutáneas/tratamiento farmacológico , Resultado del TratamientoAsunto(s)
Colaboración de las Masas/estadística & datos numéricos , Obtención de Fondos/estadística & datos numéricos , Neoplasias Cutáneas/economía , Neoplasias Cutáneas/terapia , Carcinoma Basocelular/economía , Carcinoma Basocelular/terapia , Carcinoma de Células Escamosas/economía , Carcinoma de Células Escamosas/terapia , Obtención de Fondos/métodos , Humanos , Linfoma Cutáneo de Células T/economía , Linfoma Cutáneo de Células T/terapia , Melanoma/economía , Melanoma/terapiaRESUMEN
Understanding transcription factor navigation through the nucleus remains critical for developing targeted therapeutics. The GLI1 transcription factor must maintain maximal Hedgehog pathway output in basal cell carcinomas (BCCs), and we have previously shown that resistant BCCs increase GLI1 deacetylation through atypical protein kinase Cι/λ (aPKC) and HDAC1. Here we identify a lamina-associated polypeptide 2 (LAP2) isoform-dependent nuclear chaperoning system that regulates GLI1 movement between the nuclear lamina and nucleoplasm to achieve maximal activation. LAP2ß forms a two-site interaction with the GLI1 zinc-finger domain and acetylation site, stabilizing an acetylation-dependent reserve on the inner nuclear membrane (INM). By contrast, the nucleoplasmic LAP2α competes with LAP2ß for GLI1 while scaffolding HDAC1 to deacetylate the secondary binding site. aPKC functions to promote GLI1 association with LAP2α, promoting egress off the INM. GLI1 intranuclear trafficking by LAP2 isoforms represents a powerful signal amplifier in BCCs with implications for zinc finger-based signal transduction and therapeutics.
Asunto(s)
Proteínas de Unión al ADN/metabolismo , Proteínas de la Membrana/metabolismo , Proteína con Dedos de Zinc GLI1/metabolismo , Células 3T3 , Animales , Carcinoma Basocelular/metabolismo , Línea Celular , Cromatina , Proteínas de Unión al ADN/fisiología , Células HEK293 , Proteínas Hedgehog/metabolismo , Proteínas Hedgehog/fisiología , Histona Desacetilasa 1/metabolismo , Humanos , Proteínas de la Membrana/fisiología , Ratones , Chaperonas Moleculares/metabolismo , Lámina Nuclear/metabolismo , Proteínas Nucleares/metabolismo , Isoformas de Proteínas/metabolismo , Transducción de Señal , Transactivadores/metabolismo , Factores de Transcripción/metabolismo , Proteína con Dedos de Zinc GLI1/fisiología , Dedos de ZincRESUMEN
Hedgehog pathway-dependent cancers can escape Smoothened (SMO) inhibition through mutations in genes encoding canonical hedgehog pathway components; however, around 50% of drug-resistant basal cell carcinomas (BCCs) lack additional variants of these genes. Here we use multidimensional genomics analysis of human and mouse drug-resistant BCCs to identify a noncanonical hedgehog activation pathway driven by the transcription factor serum response factor (SRF). Active SRF along with its coactivator megakaryoblastic leukemia 1 (MKL1) binds DNA near hedgehog target genes and forms a previously unknown protein complex with the hedgehog transcription factor glioma-associated oncogene family zinc finger-1 (GLI1), causing amplification of GLI1 transcriptional activity. We show that cytoskeletal activation through Rho and the formin family member Diaphanous (mDia) is required for SRF-MKL-driven GLI1 activation and for tumor cell viability. Remarkably, nuclear MKL1 staining served as a biomarker in tumors from mice and human subjects to predict tumor responsiveness to MKL inhibitors, highlighting the therapeutic potential of targeting this pathway. Thus, our study illuminates, for the first time, cytoskeletal-activation-driven transcription as a personalized therapeutic target for combatting drug-resistant malignancies.
Asunto(s)
Carcinoma Basocelular/tratamiento farmacológico , Resistencia a Antineoplásicos/genética , Factor de Respuesta Sérica/genética , Transactivadores/genética , Proteína con Dedos de Zinc GLI1/genética , Animales , Carcinoma Basocelular/genética , Carcinoma Basocelular/patología , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Regulación Neoplásica de la Expresión Génica/genética , Proteínas Hedgehog , Humanos , Ratones , Complejos Multiproteicos/genética , Transducción de Señal , Activación TranscripcionalRESUMEN
Advanced basal cell carcinomas (BCCs) circumvent Smoothened (SMO) inhibition by activating GLI transcription factors to sustain the high levels of Hedgehog (HH) signaling required for their survival. Unfortunately, there is a lack of efficacious therapies. We performed a gene expression-based drug repositioning screen in silico and identified the FDA-approved histone deacetylase (HDAC) inhibitor, vorinostat, as a top therapeutic candidate. We show that vorinostat only inhibits proliferation of BCC cells in vitro and BCC allografts in vivo at high dose, limiting its usefulness as a monotherapy. We leveraged this in silico approach to identify drug combinations that increase the therapeutic window of vorinostat and identified atypical PKC Æ/Ê (aPKC) as a HDAC costimulator of HH signaling. We found that aPKC promotes GLI1-HDAC1 association in vitro, linking two positive feedback loops. Combination targeting of HDAC1 and aPKC robustly inhibited GLI1, lowering drug doses needed in vitro, in vivo, and ex vivo in patient-derived BCC explants. We identified a bioavailable and selective small-molecule aPKC inhibitor, bringing the pharmacological blockade of aPKC and HDAC1 into the realm of clinical possibility. Our findings provide a compelling rationale and candidate drugs for combined targeting of HDAC1 and aPKC in HH-dependent cancers.
Asunto(s)
Carcinoma Basocelular/tratamiento farmacológico , Histona Desacetilasa 1/efectos de los fármacos , Inhibidores de Histona Desacetilasas/farmacología , Isoenzimas/efectos de los fármacos , Proteína Quinasa C/efectos de los fármacos , Neoplasias Cutáneas/tratamiento farmacológico , Aloinjertos , Animales , Carcinoma Basocelular/genética , Línea Celular Tumoral , Proliferación Celular/efectos de los fármacos , Biología Computacional , Combinación de Medicamentos , Descubrimiento de Drogas , Perfilación de la Expresión Génica , Regulación Neoplásica de la Expresión Génica/efectos de los fármacos , Erizos/genética , Erizos/metabolismo , Histona Desacetilasa 1/genética , Histona Desacetilasa 1/metabolismo , Inhibidores de Histona Desacetilasas/química , Isoenzimas/metabolismo , Ratones , Ratones Noqueados , Proteína Quinasa C/metabolismo , Transducción de Señal , Factores de Transcripción/efectos de los fármacos , Factores de Transcripción/genética , Proteína con Dedos de Zinc GLI1/genética , Proteína con Dedos de Zinc GLI1/metabolismoRESUMEN
The Hedgehog pathway is a potent regulator of cellular growth and plays a central role in the development of many cancers including basal cell carcinoma (BCC). The majority of BCCs arise from mutations in the Patched receptor resulting in constitutive activation of the Hedgehog pathway. Secondary driver mutations promote BCC oncogenesis and occur frequently due to the high mutational burden resulting from sun exposure of the skin. Here, we uncover novel secondary mutations in Suppressor of Fused (SUFU), the major negative regulator of the Hedgehog pathway. SUFU normally binds to a Hedgehog transcriptional activator, GLI1, in order to prevent it from initiating transcription of Hedgehog target genes. We sequenced tumor-normal pairs from patients with early sporadic BCCs. This resulted in the discovery of nine mutations in SUFU, which were functionally investigated to determine whether they help drive BCC formation. Our results show that four of the SUFU mutations inappropriately activate the Hedgehog pathway, suggesting they may act as driver mutations for BCC development. Indeed, all four of the loss of function SUFU variants were found to disrupt its binding to GLI, leading to constitutive pathway activation. Our results from functional characterization of these mutations shed light on SUFU's role in Hedgehog signaling, tumor progression, and highlight a way in which BCCs can arise.