RESUMO
BACKGROUND: Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype with limited systemic treatment options. RX-5902 is a novel anti-cancer agent that inhibits phosphorylated-p68 and thus attenuates nuclear ß-catenin signaling. The purpose of this study was to evaluate the ability of ß-catenin signaling blockade to enhance the efficacy of anti-CTLA-4 and anti-PD-1 immune checkpoint blockade in immunocompetent, preclinical models of TNBC. METHODS: Treatment with RX-5902, anti-PD-1, anti-CTLA-4 or the combination was investigated in BALB/c mice injected with the 4 T1 TNBC cell line. Humanized BALB/c-Rag2nullIl2rγnullSIRPαNOD (hu-CB-BRGS) mice transplanted with a human immune system were implanted with MDA-MB-231 cells. Mice were randomized into treatment groups according to human hematopoietic chimerism and treated with RX-5902, anti-PD-1 or the combination. At sacrifice, bone marrow, lymph nodes, spleen and tumors were harvested for flow cytometry analysis of human immune cells. RESULTS: The addition of RX-5902 to CTLA-4 or PD-1 inhibitors resulted in decreased tumor growth in the 4 T1 and human immune system and MDA-MB-231 xenograft models. Immunologic analyses demonstrated a significant increase in the number of activated T cells in tumor infiltrating lymphocytes (TILs) with RX-5902 treatment compared to vehicle (p < 0.05). In the RX-5902/nivolumab combination group, there was a significant increase in the percentage of CD4+ T cells in TILs and increased systemic granzyme B production (p < 0.01). CONCLUSIONS: Conclusions: RX-5902 enhanced the efficacy of nivolumab in a humanized, preclinical model of TNBC. Several changes in immunologic profiles were noted in mice treated with RX-5902 and the combination, including an increase in activated TILs and a decrease in human myeloid populations, that are often associated with immunosuppression in a tumor microenvironment. RX-5902 also was shown to potentiate the effects of checkpoint inhibitors of CTLA4 and the PD-1 inhibitor in the 4 T-1 murine TNBC model. These findings indicate that RX-5902 may have important immunomodulatory, as well as anti-tumor activity, in TNBC when combined with a checkpoint inhibitor.
Assuntos
Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Inibidores de Checkpoint Imunológico/farmacologia , Linfócitos do Interstício Tumoral/imunologia , Piperazinas/farmacologia , Quinoxalinas/farmacologia , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Microambiente Tumoral/imunologia , beta Catenina/antagonistas & inibidores , Animais , Apoptose , Proliferação de Células , Quimioterapia Combinada , Feminino , Humanos , Linfócitos do Interstício Tumoral/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Nus , Neoplasias de Mama Triplo Negativas/metabolismo , Neoplasias de Mama Triplo Negativas/patologia , Células Tumorais Cultivadas , Microambiente Tumoral/efeitos dos fármacos , Ensaios Antitumorais Modelo de Xenoenxerto , beta Catenina/metabolismoRESUMO
(1) Background: RX-3117 (fluorocyclopentenyl-cytosine) is a cytidine analog that inhibits DNA methyltransferase 1 (DNMT1). We investigated the mechanism and potential of RX-3117 as a demethylating agent in several in vitro models. (2) Methods: we used western blotting to measure expression of several proteins known to be down-regulated by DNA methylation: O6-methylguanine-DNA methyltransferase (MGMT) and the tumor-suppressor genes, p16 and E-cadherin. Transport of methotrexate (MTX) mediated by the proton-coupled folate transporter (PCFT) was used as a functional assay. (3) Results: RX-3117 treatment decreased total DNA-cytosine-methylation in A549 non-small cell lung cancer (NSCLC) cells, and induced protein expression of MGMT, p16 and E-cadherin in A549 and SW1573 NSCLC cells. Leukemic CCRF-CEM cells and the MTX-resistant variant (CEM/MTX, with a deficient reduced folate carrier) have a very low expression of PCFT due to promoter hypermethylation. In CEM/MTX cells, pre-treatment with RX-3117 increased PCFT-mediated MTX uptake 8-fold, and in CEM cells 4-fold. With the reference hypomethylating agent 5-aza-2'-deoxycytidine similar values were obtained. RX-3117 also increased PCFT gene expression and PCFT protein. (4) Conclusion: RX-3117 down-regulates DNMT1, leading to hypomethylation of DNA. From the increased protein expression of tumor-suppressor genes and functional activation of PCFT, we concluded that RX-3117 might have induced hypomethylation of the promotor.
Assuntos
Citidina/análogos & derivados , DNA (Citosina-5-)-Metiltransferase 1/metabolismo , Transportador de Folato Acoplado a Próton/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Linhagem Celular Tumoral , Citidina/farmacologia , DNA (Citosina-5-)-Metiltransferase 1/genética , Metilação de DNA/efeitos dos fármacos , Relação Dose-Resposta a Droga , Regulação da Expressão Gênica/efeitos dos fármacos , Humanos , Metotrexato/farmacologia , Transportador de Folato Acoplado a Próton/genética , Proteínas Supressoras de Tumor/genéticaRESUMO
Lipid-albumin nanoparticles (LAN) were synthesized for delivery of RX-0047, an antisense oligonucleotide (ASO) against the hypoxia inducible factor-1 alpha (HIF-1α) to solid tumor. These lipid nanoparticles (LNs) incorporated a human serum albumin-pentaethylenehexamine (HSA-PEHA) conjugate, which is cationic and can form electrostatic complexes with negatively charged oligonucleotides. The delivery efficiency of LAN-RX-0047 was investigated in KB cells and a KB murine xenograft model. When KB cells were treated with LAN-RX-0047, significant HIF-1α downregulation and enhanced cellular uptake were observed compared to LN-RX-0047. LN-RX-0047 and LAN-RX-0047 showed similar cytotoxicity against KB cells with IC50 values of 19.3 ± 3.8 and 20.1 ± 4.2 µM, respectively. LAN-RX-0047 was shown to be taken up by the cells via the macropinocytosis and caveolae-mediated endocytosis pathways while LN-RX-0047 was taken up by cells via caveolae-mediated endocytosis. In the KB xenograft tumor model, LAN-RX-0047 exhibited tumor suppressive activity and significantly reduced intratumoral HIF-1α expression compared to LN-RX-0047. Furthermore, LAN-RX-0047 greatly increased survival time of mice bearing KB-1 xenograft tumors at doses of either 3 mg/kg or 16 mg/kg. These results indicated that LAN-RX-0047 is a highly effective vehicle for therapeutic delivery of antisense agents to tumor.
Assuntos
Portadores de Fármacos/química , Subunidade alfa do Fator 1 Induzível por Hipóxia/antagonistas & inibidores , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Lipídeos/química , Nanopartículas/química , Oligonucleotídeos Antissenso/química , Oligonucleotídeos/química , Oligonucleotídeos/uso terapêutico , Albuminas , Animais , Western Blotting , Linhagem Celular Tumoral , Portadores de Fármacos/administração & dosagem , Células HeLa , Humanos , Camundongos , Camundongos Nus , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
INTRODUCTION: RX-3117 is an oral, small molecule cytidine analog anticancer agent with an improved pharmacological profile relative to gemcitabine and other nucleoside analogs. The agent has excellent activity against various cancer cell lines and xenografts including gemcitabine-resistant variants and it has excellent oral bioavailability; it is not a substrate for the degradation enzyme cytidine deaminase. RX-3117 is being evaluated at a daily oral schedule of 700 mg (5 days/week for 3 weeks) which results in plasma levels in the micromolar range that have been shown to be cytotoxic to cancer cells. It has shown clinical activity in refractory bladder cancer and pancreatic cancer. Areas covered: The review provides an overview of the relevant market and describes the mechanism of action, main pharmacokinetic/pharmacodynamic features and clinical development of this investigational small molecule. Expert opinion: RX-3117 is selectively activated by uridine-cytidine kinase 2 (UCK2), which is expressed only in tumors and has a dual mechanism of action: DNA damage and inhibition of DNA methyltransferase 1 (DNMT1). Because of its tumor selective activation, novel mechanism of action, excellent oral bioavailability and candidate biomarkers for patient selection, RX-3117 has the potential to replace gemcitabine in the treatment of a spectrum of cancer types.
Assuntos
Antimetabólitos Antineoplásicos/uso terapêutico , Citidina/análogos & derivados , Neoplasias/tratamento farmacológico , Administração Oral , Antimetabólitos Antineoplásicos/farmacocinética , Antimetabólitos Antineoplásicos/farmacologia , Disponibilidade Biológica , Citidina/farmacocinética , Citidina/farmacologia , Citidina/uso terapêutico , Desoxicitidina/análogos & derivados , Desoxicitidina/uso terapêutico , Humanos , Neoplasias/patologia , Seleção de Pacientes , GencitabinaRESUMO
RX-5902 is a first-in-class anticancer agent targeting phosphorylated-p68 and attenuating nuclear shuttling of ß-catenin. The purpose of this study was to evaluate the efficacy of RX-5902 in preclinical models of triple-negative breast cancer (TNBC) and to explore effects on ß-catenin expression. A panel of 18 TNBC cell lines was exposed to RX-5902, and changes in proliferation, apoptosis, cellular ploidy, and effector protein expression were assessed. Gene expression profiling was used in sensitive and resistant cell lines with pathway analysis to explore pathways associated with sensitivity to RX-5902. The activity of RX-5902 was confirmed in vivo in cell line and patient-derived tumor xenograft (PDX) models. RX-5902 demonstrated potent antiproliferative activity in vitro against TNBC cell lines with an average IC50 of 56 nmol/L in sensitive cell lines. RX-5902 treatment resulted in the induction of apoptosis, G2-M cell-cycle arrest, and aneuploidy in a subset of cell lines. RX-5902 was active in vivo against TNBC PDX models, and treatment resulted in a decrease in nuclear ß-catenin. RX-5902 exhibited dose-proportional pharmacokinetics and plasma and tumor tissue in nude mice. Pathway analysis demonstrated an increase in the epithelial-to-mesenchymal transformation (EMT), TGFß, and Wnt/ß-catenin pathways associated with sensitivity to RX-5902. RX-5902 is active against in vitro and in vivo preclinical models of TNBC. Target engagement was confirmed with decreases in nuclear ß-catenin and MCL-1 observed, confirming the proposed mechanism of action. This study supports the continued investigation of RX-5902 in TNBC and combinations with immunotherapy.
Assuntos
Antineoplásicos/administração & dosagem , Piperazinas/administração & dosagem , Quinoxalinas/administração & dosagem , Neoplasias de Mama Triplo Negativas/tratamento farmacológico , Via de Sinalização Wnt/efeitos dos fármacos , eIF-2 Quinase/metabolismo , Animais , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Camundongos , Proteína de Sequência 1 de Leucemia de Células Mieloides/metabolismo , Fosforilação , Piperazinas/farmacologia , Quinoxalinas/farmacologia , Neoplasias de Mama Triplo Negativas/metabolismo , Ensaios Antitumorais Modelo de Xenoenxerto , beta Catenina/metabolismoRESUMO
BACKGROUND: RX-0201 is an antisense oligonucleotide (ASO) against Akt1 currently in clinical trial for metastatic renal cancer. PURPOSE: To improve the delivery of RX-0201 using folate receptor-targeted lipid-albumin nanoparticles (F-LAN). METHODS: F-LAN were synthesized with the composition of DOTAP/soyPC/TPGS/folate-PEG-DSPE (25:70:4:1 m/m), a cationic human serum albumin-pentaethylenehexamine (HSA-PEHA) conjugate and RX-0201. The nanoparticles were evaluated in KB human carcinoma cells in vitro and in a KB murine xenograft tumour model in vivo for pharmacokinetics and antitumor activities. RESULTS: The F-LAN-RX-0201 had a mean particle size of 108.6 ± 5.8 nm, zeta potential of 10.5 ± 3.2 mV and ASO loading efficiency of 71.5 ± 4.5%. In KB cells, uptake and Akt1 inhibition by F-LAN-RX-0201 were greater than those of non-targeted LAN-RX-0201 and could be partially blocked by excess free folate. F-LAN-RX-0201 inhibited cell growth with an IC50 of 11.9 µM. In contrast, LAN-RX-0201 showed lower cytotoxicity with an IC50 of 32.0 µM. No significant cytotoxicity was observed with up to 250 µM of free RX-0201. Pharmacokinetic studies showed that F-LAN-RX-0201 had a longer terminal half-life than free RX-0201 (442 vs. 219 min). In a KB xenograft tumour model, F-LAN-RX-0201 exhibited greater tumour inhibition than LAN-RX-0201 at 16 mg/kg. Moreover, F-LAN-RX-0201 at 16 mg/kg showed comparable tumour inhibition compared to free RX-0201 at a much higher dose of 90 mg/kg. CONCLUSIONS: F-LAN-RX-0201 showed promise as a therapeutic agent for tumours with elevated folate-receptor expression.
Assuntos
Carcinoma/terapia , Nanopartículas , Oligonucleotídeos Antissenso/administração & dosagem , Oligonucleotídeos/administração & dosagem , Proteínas Proto-Oncogênicas c-akt/antagonistas & inibidores , Albuminas/química , Animais , Carcinoma/patologia , Ácidos Graxos Monoinsaturados/química , Receptores de Folato com Âncoras de GPI/metabolismo , Ácido Fólico/química , Humanos , Células KB , Lipídeos/química , Camundongos , Camundongos Endogâmicos ICR , Camundongos Nus , Oligonucleotídeos/farmacologia , Oligonucleotídeos Antissenso/farmacologia , Tamanho da Partícula , Fosfatidiletanolaminas/química , Polietilenoglicóis/química , Compostos de Amônio Quaternário/química , Vitamina E/química , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Synthesis of fluorocyclopentenyl pyrimidine nucleosides 6-9 was enantiopurely accomplished employing oxidative rearrangement, RCM reaction and electrophilic fluorination starting from d-ribose. Cytosine analog 8 was found to exhibit significant anticancer activity in various human tumor cell lines.
Assuntos
Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Pirimidinas/síntese química , Pirimidinas/farmacologia , Antineoplásicos/química , Linhagem Celular Tumoral , Desenho de Fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Pirimidinas/químicaRESUMO
RX-3117 (fluorocyclopentenyl-cytosine) is a novel cytidine analog currently being evaluated in a Phase Ib clinical trial in cancer patients with solid tumors. The radiosensitizing effect of RX-3117 was studied in A2780 ovarian cancer cells and non-small cell lung cancer cell lines and related to cell survival and the effect on cell cycle and cell cycle proteins. RX-3117 has a schedule-dependent radiosensitizing effect, but only at pre-incubation (dose modifying factors: 1.4-1.8), observed at pulse and fractionated irradiation. Radiosensitizion was also seen in a three-dimensional spheroid model. At the low radiosensitizing concentration, RX-3117 in combination with radiation led to an accumulation of cells in S-phase, which was accompanied with an increase of cell cycle proteins such as p-Chk2 and p-cdc25C. In addition, RX-3117 caused DNA damage and increased apoptosis. In conclusion, our in vitro experiments showed a radiosensitizing effect of RX-3117.
Assuntos
Citidina/análogos & derivados , Radiossensibilizantes/farmacologia , Apoptose/efeitos dos fármacos , Apoptose/efeitos da radiação , Pontos de Checagem do Ciclo Celular , Linhagem Celular Tumoral , Citidina/farmacologia , Dano ao DNA , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Humanos , Neoplasias Pulmonares , Neoplasias OvarianasRESUMO
Fluorocyclopentenylcytosine (RX-3117) is an orally available cytidine analog, currently in Phase I clinical trial. RX-3117 has promising antitumor activity in various human tumor xenografts including gemcitabine resistant tumors. RX-3117 is activated by uridine-cytidine kinase (UCK). Since UCK exists in two forms, UCK1 and UCK2, we investigated which form is responsible for RX-3117 phosphorylation. For that purpose we transfected A549 and SW1573 cell lines with UCK-siRNAs. Transfection of UCK1-siRNA efficiently downregulated UCK1-mRNA, but not UCK2-mRNA expression, and did not affect sensitivity to RX-3117. However, transfection of UCK2-siRNA completely downregulated UCK2-mRNA and protein and protected both A549 and SW1573 against RX-3117. UCK enzyme activity in two panels of tumor cell lines and xenograft cells correlated only with UCK2-mRNA expression (r = 0.803 and 0.915, respectively), but not with UCK1-mRNA. Moreover, accumulation of RX-3117 nucleotides correlated with UCK2 expression. In conclusion, RX-3117 is activated by UCK2 which may be used to select patients potentially sensitive to RX-3117.
Assuntos
Citidina/análogos & derivados , Uridina Quinase/metabolismo , Ciclo Celular/efeitos dos fármacos , Ciclo Celular/genética , Morte Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Proliferação de Células/genética , Citidina/química , Citidina/farmacologia , Regulação para Baixo/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Fosforilação/efeitos dos fármacos , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , RNA Interferente Pequeno/metabolismo , Análise de Regressão , Reprodutibilidade dos Testes , Especificidade por Substrato/efeitos dos fármacos , Transfecção , Uridina Quinase/genéticaRESUMO
We showed previously that, after spinal cord injury (SCI), tumor necrosis factor-alpha (TNF-alpha) may serve as an external signal, initiating apoptosis in neurons and oligodendrocytes. To further characterize the apoptotic cascade initiated by TNF-alpha after SCI, we examined the expression of TNF-alpha, inducible nitric oxide (NO) synthase (iNOS), and the level of NO after SCI. Western blots and reverse transcription polymerase chain reactions showed an early upregulation of TNF-alpha after injury. A peak TNF-alpha expression was observed within 1 h of injury. By 4 h after injury, the expression of iNOS and the level of NO were markedly increased in the injured spinal cord. Terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate-biotin nick end labeling (TUNEL)-positive cells were also first observed in the lesioned area 4 h after SCI. The largest number of TUNEL-positive cells was observed between 24-48 h after SCI. Injecting a neutralizing antibody against TNF-alpha into the lesion site after injury significantly reduced the expression of iNOS, the level of NO and the number of TUNEL-positive cells in the injured spinal cord. Injecting the NOS inhibitors, N(G)-monomethyl-L-arginine monoacetate and S-methylisothiourea sulfate, or an NO scavenger, carboxy-PTIO, into the lesion site also significantly reduced the level of NO and the degree of DNA laddering in the injured spinal cord. These data suggest that after SCI, apoptosis induced by TNF-alpha may be mediated in part by NO via upregulation of iNOS, induced in response to TNF-alpha.
Assuntos
Apoptose/fisiologia , Traumatismos da Medula Espinal/fisiopatologia , Fator de Necrose Tumoral alfa/biossíntese , Animais , Anticorpos/farmacologia , Apoptose/efeitos dos fármacos , Indução Enzimática , Masculino , Compressão Nervosa , Óxido Nítrico/antagonistas & inibidores , Óxido Nítrico/biossíntese , Óxido Nítrico Sintase/antagonistas & inibidores , Óxido Nítrico Sintase/metabolismo , Óxido Nítrico Sintase Tipo II , Ratos , Ratos Sprague-Dawley , Traumatismos da Medula Espinal/patologia , Fatores de Tempo , Fator de Necrose Tumoral alfa/imunologiaRESUMO
On the basis of the potent biological activity of cyclopentenyl-pyrimidines, fluorocyclopentenyl-pyrimidines were designed and synthesized from D-ribose. Among these, the cytosine derivative 5a showed highly potent antigrowth effects in a broad range of tumor cell lines and very potent antitumor activity in a nude mouse tumor xenograft model implanted with A549 human lung cancer cells. However, its 2'-deoxycytidine derivative 5b did not show any antigrowth effects, indicating that 2'-hydroxyl group is essential for the biological activity.
Assuntos
Antineoplásicos/síntese química , Ciclopentanos/síntese química , Citosina/análogos & derivados , Neoplasias Pulmonares/tratamento farmacológico , Animais , Antineoplásicos/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Ciclopentanos/farmacologia , Citosina/farmacologia , Humanos , Neoplasias Pulmonares/patologia , Masculino , Camundongos , Camundongos Nus , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Novel pyrimidine nucleosides with fluorocyclopentene ring were synthesized from D-ribose via stereoselective Grignard reaction and electrophilic vinyl fluorination as key steps. Among compounds tested, cytosine derivative 15a was found to show high growth inhibition against a broad range of human tumor cell lines.