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The fibroblast growth factor receptor 2 (FGFR2) is a key component in cellular signaling networks, and its dysfunctional activation has been implicated in various diseases including cancer and developmental disorders. Mutations at the activation loop (A-loop) have been suggested to trigger an increased basal kinase activity. However, the molecular mechanism underlying this highly dynamic process has not been fully understood due to the limitation of static structural information. Here, we conducted multiple, large-scale Gaussian accelerated molecular dynamics simulations of five (K659E, K659N, K659M, K659Q, and K659T) FGFR2 mutants at the A-loop, and comprehensively analyzed the dynamic molecular basis of FGFR2 activation. The results quantified the population shift of each system, revealing that all mutants had a higher proportion of active-like states. Using Markov state models, we extracted the representative structure of different conformational states and identified key residues related to the increased kinase activity. Furthermore, community network analysis showed enhanced information connections in the mutants, highlighting the long-range allosteric communication between the A-loop and the hinge region. Our findings may provide insights into the dynamic mechanism for FGFR2 dysfunctional activation and allosteric drug discovery.Communicated by Ramaswamy H. Sarma.
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Simulação de Dinâmica Molecular , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos/genética , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos/química , Receptor Tipo 2 de Fator de Crescimento de Fibroblastos/metabolismo , Fosforilação , MutaçãoRESUMO
BACKGROUND: Early and late recurrence of hepatocellular carcinoma (HCC) have different clinical outcomes, especially for those accompanied by microvascular invasion (MVI), but the definition of early recurrence remains controversial. Therefore, a reasonable identification of the early recurrence time for HCC is urgently needed. METHODS: Resected recurrence patients were enrolled and divided into two cohorts, one for identification of the early recurrence time and another for verification of the accuracy of the point. Univariable and multivariable Cox regression analyses were adopted to identify the prognostic factors of recurrence HCC (rHCC) and Kaplan-Meier method was applied to analyze the overall survival (OS). The appropriate cutoff value was determined by the exhaustive method using different recurrence intervals from 1 to 24 months in turn. RESULTS: In total, 292 resected rHCC patients were analyzed to calculate the early recurrence interval, and another 421 resected rHCC patients with MVI were enrolled to verify the efficacy of adjuvant transarterial chemoembolization (TACE) in this recurrence interval. MVI was identified as an independent risk factor by multivariable analysis. The OS of rHCC patients without MVI is better than that of patients with MVI when the recurrence time was within 13 months, while not beyond 13 months. The verification cohort demonstrated that adjuvant TACE provided longer survival for rHCC with MVI when the recurrence time was within 13 months, while not beyond 13 months. CONCLUSION: For HCC patients with MVI who underwent R0 resection, 13 months may be a reasonable early recurrence time point, and within this interval, postoperative adjuvant TACE may result in longer survival compared with surgery alone.
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Carcinoma Hepatocelular , Quimioembolização Terapêutica , Neoplasias Hepáticas , Humanos , Carcinoma Hepatocelular/patologia , Neoplasias Hepáticas/patologia , Estudos Retrospectivos , Quimioembolização Terapêutica/métodos , Invasividade Neoplásica , Hepatectomia , Adjuvantes Imunológicos , Recidiva Local de Neoplasia/patologiaRESUMO
Fibroblast growth factor receptors (FGFRs) play critical roles in the regulation of cell growth, differentiation, and proliferation. Specifically, FGFR2 gene amplification has been implicated in gastric and breast cancer. Pan-FGFR inhibitors often cause large toxic side effects, and the highly conserved ATP-binding pocket in the FGFR1/2/3 isoforms poses an immense challenge in designing selective FGFR2 inhibitors. Recently, an indazole-based inhibitor has been discovered that can selectively target FGFR2. However, the detailed mechanism involved in selective inhibition remains to be clarified. To this end, we performed extensive molecular dynamics simulations of the apo and inhibitor-bound systems along with multiple analyses, including Markov state models, principal component analysis, a cross-correlation matrix, binding free energy calculation, and community network analysis. Our results indicated that inhibitor binding induced the phosphate-binding loop (P-loop) of FGFR2 to switch from the open to the closed conformation. This effect enhanced extensive hydrophobic FGFR2-inhibitor contacts, contributing to inhibitor selectivity. Moreover, the key conformational intermediate states, dynamics, and driving forces of this transformation were uncovered. Overall, these findings not only provided a structural basis for understanding the closed P-loop conformation for therapeutic potential but also shed light on the design of selective inhibitors for treating specific types of cancer.
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Neoplasias da Mama , Simulação de Dinâmica Molecular , Humanos , Feminino , Receptores de Fatores de Crescimento de Fibroblastos , Transdução de Sinais , Diferenciação Celular , Isoformas de Proteínas/metabolismoRESUMO
SUMOylation regulates various cellular process and SENP1 (SUMO-specific protease 1) serves as a SUMO (small ubiquitin-related modifier) specific protease that participates in the SUMO cycle. Given its extensive influences on metabolic activities, SENP1 has gained more and more attentions in clinical treatments. However, there remains a question on why does the SENP1 prefer to process SUMO1 rather than SUMO2. Here, we performed molecular dynamics simulations of SENP1-SUMO1, SENP1-SUMO2, and apo SENP1 systems and observed distinct conformational dynamics in the upper half of the clamp and the three loops in the catalytic center of the SENP1. Principal component analysis revealed that the most prominent canonical variable represented the spatial distribution of the upper half of the clamp, while the openness of the cleft was closely related to the catalytic ability of SENP1. Further analysis of the SENP1-SUMO interactions revealed that the extensive and strong interactions between the SENP1 and SUMO1 were both in the interface of the upper half region and the catalytic center. Dynamic cross-correlation matrix analysis demonstrated that the inter-residue correlations in the SUMO1 system was much stronger, especially in the two essential regions belonging to the upper and lower half of cleft. Based on these observations, we proposed an allosteric propagation model and further testified it using the community analysis. These results revealed the propagation pathway of allosteric communication that contributed to the substrate discrimination of SENP1 upon SUMO1 and SUMO2.Communicated by Ramaswamy H. Sarma.
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Cisteína Endopeptidases , Proteína SUMO-1 , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina , Simulação de Dinâmica Molecular , Ubiquitina , Cisteína Endopeptidases/química , Proteína SUMO-1/química , Proteínas Modificadoras Pequenas Relacionadas à Ubiquitina/químicaRESUMO
Purpose: This study aimed to assess the efficacy and safety of a triple therapy that comprises transarterial chemoembolization (TACE), antiangiogenic-targeted therapy, and programmed death-1 (PD-1) inhibitors in a real-world cohort of patients with unresectable hepatocellular carcinoma (HCC) with portal vein tumor thrombus (PVTT). Methods: Consecutive patients treated with TACE combined with antiangiogenic therapy and PD-1 inhibitors at the Eastern Hepatobiliary Surgery Hospital between June 2019 and May 2021 were enrolled. The baseline characteristics and treatment course of the patients were recorded. The tumor response was evaluated based on the Response Evaluation Criteria in Solid Tumors (RECIST) 1.1 and HCC-specific modified RECIST (mRECIST). The overall survival (OS) and progression-free survival (PFS) of the patients were analyzed using the Kaplan-Meier method. Adverse events (AEs) were assessed according to the National Cancer Institute Common Terminology Criteria for Adverse Events version 5.0. Results: As of the data cutoff on 30 August 2021, the median follow-up time was 10.0 (3.9-28.4) months. A total of 39 eligible patients were included. The objective response rate (ORR) and the disease control rate (DCR) were 35.9% and 74.4% according to the RECIST 1.1, and 48.7% and 84.6% according to mRECIST criteria, respectively. The median OS and PFS were 14.0 and 9.2 months, respectively. Moreover, 34 (87.2%) patients experienced at least one treatment-related AE and 8 (20.5%) patients experienced grade 3/4 treatment-related AEs. The most common treatment- and laboratory-related AEs were hypertension (46.2%) and decreased albumin (53.8%), respectively. No treatment-related mortality occurred during the study period. Conclusions: TACE combined with antiangiogenic-targeted therapy and immune checkpoint inhibitors may have promising anticancer activity in unresectable HCC patients with PVTT. AEs were manageable, with no unexpected overlapping toxicities.
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Fine particle (PM2.5, less than 2.5 micrometers in diameter) is regarded as a harmful carcinogen. However, the molecular mechanisms of the carcinogenic effects of ambient fine particles have not been fully elucidated, and therapeutic options to address this major public health challenge are lacking. Here, we present global gene-specific DNA methylation and transcriptomic (RNA-Seq) analyses after HBE cells were exposed to fine particles on a portable, small, and all-in-one organ-level lung-mimicking air-liquid interface exposure (MALIE) microfluidic platform. A series of cancer-related signal transduction pathways were activated. ErbB1, ErbB2, and ErbB3 gene expression altered by fine particle exposure was the result of changes in the cellular DNA methylome. The protein expression of ErbB family was inhibited by drugs and could regulate downstream Grb2/Raf pathway and Akt/MDM2 pathway. All of the above results indicated that ErbB family may be promising drug targets for air pollution-related diseases and that inhibitor drugs can be used as therapeutic options to treat these diseases.
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Metilação de DNA , Microfluídica , Transcriptoma , Pulmão , Material Particulado/toxicidadeRESUMO
While host miRNA usually plays an antiviral role, the relentless tides of viral evolution have carved out a mechanism to recruit host miRNA as a viral protector. By complementing miR-122 at the 5' end of the genome, the hepatitis C virus (HCV) gene can form a complex with Argonaute 2 (Ago2) protein to protect the 5' end of HCV RNA from exonucleolytic attacks. Experiments showed that the disruption of the stem-loop 1(SL1) structure and the 9th nucleotide (T9) of HCV site 1 RNA could enhance the affinity of the Ago2 protein to the HCV site 1 RNA (target RNA). However, the underlying mechanism of how the conformation and dynamics of the Ago2: miRNA: target RNA complex is affected by the SL1 and T9 remains unclear. To address this, we performed large-scale molecular dynamics simulations on the AGO2-miRNA complex binding with the WT target, T9-abasic target and SL1-disruption target, respectively. The results revealed that the T9 and SL1 structures could induce the departing motion of the PAZ, PIWI and N domains, propping up the mouth of the central groove which accommodates the target RNA, causing the instability of the target RNA and disrupting the Ago2 binding. The coordinated motion among the PAZ, PIWI and N domains were also weakened by the T9 and SL1 structures. Moreover, we proposed a new model wherein the Ago2 protein could adopt a more constraint conformation with the proximity and more correlated motions of the PAZ, N and PIWI domains to protect the target RNA from dissociation. These findings reveal the mechanism of the Ago2-miRNA complex's protective effect on the HCV genome at the atomic level, which will offer guidance for the design of drugs to confront the protection effect and engineering of Ago2 as a gene-regulation tool.
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Hepatite C , MicroRNAs , Humanos , Hepacivirus/genética , RNA Viral/genética , RNA Viral/metabolismo , Regiões 5' não Traduzidas , Hepatite C/prevenção & controle , MicroRNAs/genética , MicroRNAs/metabolismoRESUMO
As a member of the death-associated protein kinase (DAPK) family, STK17B plays an important role in the regulation of cellular apoptosis and has been considered as a promising drug target for hepatocellular carcinoma. However, the highly conserved ATP-binding site of protein kinases represents a challenge to design selective inhibitors for a specific DAPK isoform. In this study, molecular docking, multiple large-scale molecular dynamics (MD) simulations, and binding free energy calculations were performed to decipher the molecular mechanism of the binding selectivity of PKIS43 toward STK17B against its high homology STK17A. MD simulations revealed that STK17A underwent a significant conformational arrangement of the activation loop compared to STK17B. The binding free energy predictions suggested that the driving force to control the binding selectivity of PKIS43 was derived from the difference in the protein-ligand electrostatic interactions. Furthermore, the per-residue free energy decomposition unveiled that the energy contribution from Arg41 at the phosphate-binding loop of STK17B was the determinant factor responsible for the binding specificity of PKIS43. This study may provide useful information for the rational design of novel and potent selective inhibitors toward STK17B.
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Neoplasias Hepáticas , Simulação de Dinâmica Molecular , Proteínas Reguladoras de Apoptose/metabolismo , Sítios de Ligação , Humanos , Ligantes , Simulação de Acoplamento Molecular , Ligação Proteica , Proteínas Serina-Treonina QuinasesRESUMO
Small ubiquitin-related modifier (SUMO)-specific protease 1 (SENP1) is a cysteine protease that catalyzes the cleavage of the C-terminus of SUMO1 for the processing of SUMO precursors and deSUMOylation of target proteins. SENP1 is considered to be a promising target for the treatment of hepatocellular carcinoma (HCC) and prostate cancer. SENP1 Gln597 is located at the unstructured loop connecting the helices α4 to α5. The Q597A mutation of SENP1 allosterically disrupts the hydrolytic reaction of SUMO1 through an unknown mechanism. Here, extensive multiple replicates of microsecond molecular dynamics (MD) simulations, coupled with principal component analysis, dynamic cross-correlation analysis, community network analysis, and binding free energy calculations, were performed to elucidate the detailed mechanism. Our MD simulations showed that the Q597A mutation induced marked dynamic conformational changes in SENP1, especially in the unstructured loop connecting the helices α4 to α5 which the mutation site occupies. Moreover, the Q597A mutation caused conformational changes to catalytic Cys603 and His533 at the active site, which might impair the catalytic activity of SENP1 in processing SUMO1. Moreover, binding free energy calculations revealed that the Q597A mutation had a minor effect on the binding affinity of SUMO1 to SENP1. Together, these results may broaden our understanding of the allosteric modulation of the SENP1-SUMO1 complex.
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Carcinoma Hepatocelular , Cisteína Endopeptidases , Neoplasias Hepáticas , Proteína SUMO-1 , Carcinoma Hepatocelular/enzimologia , Carcinoma Hepatocelular/genética , Cisteína Endopeptidases/genética , Cisteína Endopeptidases/metabolismo , Humanos , Neoplasias Hepáticas/enzimologia , Neoplasias Hepáticas/genética , Masculino , Mutação , Peptídeo Hidrolases/genética , Proteína SUMO-1/genética , Proteína SUMO-1/metabolismoRESUMO
As a member of the death-associated protein kinase family of serine/threonine kinases, the STK17B has been associated with diverse diseases such as hepatocellular carcinoma. However, the conformational dynamics of the phosphate-binding loop (P-loop) in the determination of inhibitor selectivity profile to the STK17B are less understood. Here, a multi-microsecond length molecular dynamics (MD) simulation of STK17B in the three different states (ligand-free, ADP-bound, and ligand-bound states) was carried out to uncover the conformational plasticity of the P-loop. Together with the analyses of principal component analysis, cross-correlation and generalized correlation motions, secondary structural analysis, and community network analysis, the conformational dynamics of the P-loop in the different states were revealed, in which the P-loop flipped into the ADP-binding site upon the inhibitor binding and interacted with the inhibitor and the C-lobe, strengthened the communication between the N- and C-lobes. These resulting interactions contributed to inhibitor selectivity profile to the STK17B. Our results may advance our understanding of kinase inhibitor selectivity and offer possible implications for the design of highly selective inhibitors for other protein kinases.
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Background: Hepatocellular carcinoma (HCC) with bile duct tumor thrombus (BDTT) is rare. The aim of this study is to evaluate the long-term prognosis of liver resection (LR) versus transcatheter arterial chemoembolization (TACE) in these patients. Methods: Data from HCC patients with BDTT who underwent liver resection and TACE were analyzed respectively. Propensity score matching (PSM) analysis was performed in these patients. Results: A total of 145 HCC patients with BDTT were divided into two groups: the LR group (n = 105) and the TACE group (n = 40). The median OS in the LR group was 8.0 months longer than that in the TACE group before PSM (21.0 vs. 13.0 months, P <0.001) and 9.0 months longer after PSM (20.0 vs. 11.0 months, P <0.001). The median DFS in the LR group was 3.5 months longer than that in the TACE group before PSM (7.0 vs. 3.5 months, P = 0.007) and 5 months longer after PSM (7.0 vs. 2.0 months, P = 0.007). Conclusion: If surgery is technically feasible, liver resection provides better prognosis for HCC patients with BDTT compared with TACE.
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Argonaute (AGO) proteins, the core of RNA-induced silencing complex, are guided by microRNAs (miRNAs) to recognize target RNA for repression. The miRNA-target RNA recognition forms initially through pairing at the seed region while the additional supplementary pairing can enhance target recognition and compensate for seed mismatch. The extension of miRNA lengths can strengthen the target affinity when pairing both in the seed and supplementary regions. However, the mechanism underlying the effect of the supplementary pairing on the conformational dynamics and the assembly of AGO-RNA complex remains poorly understood. To address this, we performed large-scale molecular dynamics simulations of AGO-RNA complexes with different pairing patterns and miRNA lengths. The results reveal that the additional supplementary pairing can not only strengthen the interaction between miRNA and target RNA, but also induce the increased plasticity of the PAZ domain and enhance the domain connectivity among the PAZ, PIWI, N domains of the AGO protein. The strong community network between these domains tightens the mouth of the supplementary chamber of AGO protein, which prevents the escape of target RNA from the complex and shields it from solvent water attack. Importantly, the inner stronger matching pairs between the miRNA and target RNA can compensate for weaker mismatches at the edge of supplementary region. These findings provide guidance for the design of miRNA mimics and anti-miRNAs for both clinical and experimental use and open the way for further engineering of AGO proteins as a new tool in the field of gene regulation.
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BACKGROUND: Microvascular invasion (MVI) is a risk factor of post-hepatectomy tumor recurrence for hepatocellular carcinoma (HCC). The patterns, treatments, and prognosis have not been documented in HCC patients with MVI. METHODS: A multicenter database of patients with HCC and MVI following resection was analyzed. The clinicopathological and initial operative data, timing and first sites of recurrence, recurrence management, and long-term survival outcomes were analyzed. RESULTS: Of 1517 patients included, the median follow-up was 39.7 months. Tumor recurrence occurred in 928 patients, with 49% within 6 months of hepatectomy and 60% only in the liver. The incidence of intrahepatic only recurrence gradually increased with time after 6 months. Patients who developed recurrence within 6 months of hepatectomy had worse survival outcomes than those who developed recurrence later. Patients who developed intrahepatic only recurrence had better prognosis than those with either extrahepatic only recurrence or those with intra- and extrahepatic recurrence. Repeat resection of recurrence with curative intent resulted in better outcomes than other treatment modalities. CONCLUSION: Post-hepatectomy tumor recurrence in patients with HCC and MVI had unique characteristics and recurrence patterns. Early detection of tumor recurrence and repeat liver resection with curative intent resulted in improved long-term survival outcomes.
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Carcinoma Hepatocelular , Neoplasias Hepáticas , Hepatectomia/efeitos adversos , Humanos , Invasividade Neoplásica , Recidiva Local de Neoplasia/patologia , Prognóstico , Estudos Retrospectivos , Fatores de RiscoRESUMO
BACKGROUND: Microvascular invasion (MVI) adversely affects long-term survival in patients with hepatitis B virus (HBV)-related hepatocellular carcinoma (HCC). This study aimed to examine the association between preoperative type 2 diabetes mellitus (T2DM) with incidences of MVI and prognosis in HBV-related HCC after liver resection (LR). MATERIAL AND METHODS: Data of HBV-related HCC patients who underwent LR as an initial therapy from four hospitals in China were retrospectively collected. Clinicopathological factors associated with the incidence of MVI were identified using univariate and multivariate logistic regression analysis. The recurrence-free survival (RFS) and overall survival (OS) curves between different cohorts of patients were generated using the Kaplan-Meier method and compared using the log-rank test. RESULTS: Of 1473 patients who were included, 219 (14.9%) patients had T2DM. Preoperative T2DM, HBV DNA load, antiviral treatment, AFP level, varices, and tumor encapsulation were identified to be independent predictors of the incidence of MVI. Patients with HBV-related HCC and T2DM had a higher incidence of MVI (65.8%) than those without T2DM (55.4%) (P = 0.004). The RFS and OS were significantly worse in patients with T2DM than those without T2DM (median RFS: 11.1 vs 16.7 months; OS: 26.4 vs 42.6 months, both P < 0.001). Equivalent results were obtained in HCC patients with MVI who had or did not have T2DM (median RFS: 10.0 vs 15.9 months; OS: 24.5 vs 37.9 months, both P < 0.001). CONCLUSIONS: Preoperative T2DM was an independent risk factor of incidence of MVI. Patients with HBV-related HCC and T2DM had worse prognosis than those without T2DM after LR.
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Carcinoma Hepatocelular/patologia , Diabetes Mellitus Tipo 2/epidemiologia , Hepatite B Crônica/complicações , Neoplasias Hepáticas/patologia , Microvasos/patologia , Adulto , Idoso , Carcinoma Hepatocelular/etiologia , Carcinoma Hepatocelular/cirurgia , Intervalo Livre de Doença , Feminino , Hepatectomia , Humanos , Neoplasias Hepáticas/etiologia , Neoplasias Hepáticas/cirurgia , Modelos Logísticos , Masculino , Pessoa de Meia-Idade , Análise Multivariada , Invasividade Neoplásica , Estudos Retrospectivos , Taxa de SobrevidaRESUMO
CRISPR-Cas systems are prokaryotic adaptive immunity against invading phages and plasmids. Phages have evolved diverse protein inhibitors of CRISPR-Cas systems, called anti-CRISPR (Acr) proteins, to neutralize this CRISPR machinery. In response, bacteria have co-evolved Cas variants to escape phage's anti-CRISPR strategies, called anti-anti-CRISPR systems. Here we explore the anti-CRISPR allosteric inhibition and anti-anti-CRISPR rescue mechanisms between Streptococcus thermophilus Cas9 (St1Cas9) and the anti-CRISPR protein AcrIIA6 at the atomic level, by generating mutants of key residues in St1Cas9. Extensive unbiased molecular dynamics simulations show that the functional motions of St1Cas9 in the presence of AcrIIA6 differ substantially from those of St1Cas9 alone. AcrIIA6 binding triggers a shift of St1Cas9 conformational ensemble towards a less catalytically competent state; this state significantly compromises protospacer adjacent motif (PAM) recognition and nuclease activity by altering interdependently conformational dynamics and allosteric signals among nuclease domains, PAM-interacting (PI) regions, and AcrIIA6 binding motifs. Via in vitro DNA cleavage assays, we further elucidate the rescue mechanism of efficiently escaping AcrIIA6 inhibition harboring St1Cas9 triple mutations (G993K/K1008M/K1010E) in the PI domain and identify the evolutionary landscape of such mutational escape within species. Our results provide mechanistic insights into Acr proteins as natural brakes for the CRISPR-Cas systems and a promising potential for the design of allosteric Acr peptidomimetics.
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RAS, a member of the small GTPase family, functions as a binary switch by shifting between inactive GDP-loaded and active GTP-loaded state. RAS gain-of-function mutations are one of the leading causes in human oncogenesis, accounting for â¼19% of the global cancer burden. As a well-recognized target in malignancy, RAS has been intensively studied in the past decades. Despite the sustained efforts, many failures occurred in the earlier exploration and resulted in an 'undruggable' feature of RAS proteins. Phosphorylation at several residues has been recently determined as regulators for wild-type and mutated RAS proteins. Therefore, the development of RAS inhibitors directly targeting the RAS mutants or towards upstream regulatory kinases supplies a novel direction for tackling the anti-RAS difficulties. A better understanding of RAS phosphorylation can contribute to future therapeutic strategies. In this review, we comprehensively summarized the current advances in RAS phosphorylation and provided mechanistic insights into the signaling transduction of associated pathways. Importantly, the preclinical and clinical success in developing anti-RAS drugs targeting the upstream kinases and potential directions of harnessing allostery to target RAS phosphorylation sites were also discussed.
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BACKGROUND: The presence of hepatic vein tumor thrombus (HVTT) is a major determinant of survival outcomes in hepatocellular carcinoma (HCC) patients. This study compared survival outcomes between liver resection (LR) and intensity-modulated radiation therapy (IMRT) in HCC patients with HVTT. METHODS: Data from patients who underwent LR or IMRT for HCC with HVTT at the Eastern Hepatobiliary Surgery Hospital were retrospectively analyzed. Their survival outcomes were compared before and after propensity score matching (PSM). RESULTS: Three hundred and seven HCC patients with HVTT who underwent either LR (n=140) or IMRT (n=167) were enrolled. PSM matched 82 pairs of patients. The overall survival (OS) and recurrence-free survival (RFS) rates were significantly higher for patients in the LR group than those in the IMRT group. On subgroup analysis, significantly better survival outcomes were obtained after LR than IMRT in patients with peripheral type of HVTT (pHVTT) and major type of HVTT (mHVTT). However, similar survival outcomes were obtained after LR and IMRT when the HVTT had developed into inferior vena cava tumor thrombus (IVCTT). CONCLUSIONS: LR resulted in significantly better survival outcomes in HCC patients with HVTT when compared to IMRT. Once the HVTT had developed IVCTT, LR and IMRT resulted in similarly bad survival outcomes.
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BACKGROUND: Hepatocellular carcinoma (HCC) is characterized by the neo-angiogenesis induced by tumor and adjacent cells. It is a leading cancer-related cause of death. Morphine has effects on angiogenesis with pro-angiogenic or anti-angiogenic phonotypes. This study explores the function of morphine on cancer cell growth, angiogenesis and the underlying mechanism in HCC. METHODS: Morphine was used to treat BEL-7402 or HCC-LM3 cells and human umbilical vein endothelial cells (HUVECs) were subsequently incubated in the conditioned media (CM) of HCC cells. The potential effects of cell proliferation, migration and tube formation of CM-treated HUVECs were investigated. Furthermore, the angiogenesis regulated factors of VEGFA, PIGF, ANG-1, ANG-2, FGF-1 and FGF-2 were assessed. siRNA and LY294002 were further used to explore the mechanism mediating the effects of morphine on the angiogenesis pathway. The neovascularization effect by morphine was confirmed through the use of human HCC cancer heterotopic mouse model in vivo. RESULTS: A significantly increased cell proliferation, migration, and tube formation effect of HUVECs induced by the CM from HCC cell lines treated with morphine was observed. More VEGFA secretion in CM from LM3 or BEL-7402 cell lines was found than the controls (P=0.03 and P=0.027, respectively). VEGFA knock-down could significantly reverse cell proliferation, migration and tube formation induced by the CM from HCC cell lines with morphine treatment. Further molecular experiments indicated that VEGFA secretion was activated by morphine potentially through the PI3K/Akt/HIF-1α pathway. Morphine-induced neovascularization was also observed by the IHC of CD31 and VEGFA. CONCLUSIONS: Morphine promotes angiogenesis in hepatocellular carcinoma possibly through the activation of the PI3K/Akt/HIF-1α pathway and VEGFA stimulation.
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G protein-coupled receptors (GPCRs) are the most common proteins targeted by approved drugs. A complete mechanistic elucidation of large-scale conformational transitions underlying the activation mechanisms of GPCRs is of critical importance for therapeutic drug development. Here, we apply a combined computational and experimental framework integrating extensive molecular dynamics simulations, Markov state models, site-directed mutagenesis, and conformational biosensors to investigate the conformational landscape of the angiotensin II (AngII) type 1 receptor (AT1 receptor) - a prototypical class A GPCR-activation. Our findings suggest a synergistic transition mechanism for AT1 receptor activation. A key intermediate state is identified in the activation pathway, which possesses a cryptic binding site within the intracellular region of the receptor. Mutation of this cryptic site prevents activation of the downstream G protein signaling and ß-arrestin-mediated pathways by the endogenous AngII octapeptide agonist, suggesting an allosteric regulatory mechanism. Together, these findings provide a deeper understanding of AT1 receptor activation at an atomic level and suggest avenues for the design of allosteric AT1 receptor modulators with a broad range of applications in GPCR biology, biophysics, and medicinal chemistry.