Decoding the Conformational Selective Mechanism of FGFR Isoforms: A Comparative Molecular Dynamics Simulation.

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.

Investigation of PM2.5-induced carcinogenic effects through mediation of ErbB family based on DNA methylation and transcriptomics analysis by a lung-mimicking microfluidic platform.

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.

Mechanistic Insights into the Mechanism of Inhibitor Selectivity toward the Dark Kinase STK17B against Its High Homology STK17A.

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.

Insights into the Allosteric Effect of SENP1 Q597A Mutation on the Hydrolytic Reaction of SUMO1 via an Integrated Computational Study.

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.

Patterns, treatments, and prognosis of tumor recurrence after resection for hepatocellular carcinoma with microvascular invasion: a multicenter study from China.

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.

An Eastern Hepatobiliary Surgery Hospital/Portal Vein Tumor Thrombus Scoring System as an Aid to Decision Making on Hepatectomy for Hepatocellular Carcinoma Patients With Portal Vein Tumor Thrombus: A Multicenter Study.

Portal vein tumor thrombus (PVTT) is a significant poor prognostic factor for hepatocellular carcinoma (HCC). Patients with PVTT limited to a first-order branch of the main portal vein (MPV) or above could benefit from negative margin (R0) liver resection (LR). An Eastern Hepatobiliary Surgery Hospital (EHBH)/PVTT scoring system was established to predict the prognosis of HCC patients with PVTT after R0 LR and guide selection of subgroups of patients that could benefit from LR. HCC patients with PVTT limited to a first-order branch of the MPV or above who underwent R0 LR as an initial therapy were included. The EHBH-PVTT score was developed from a retrospective cohort in the training cohort using a Cox regression model and validated in a prospective internal validation cohort and three external validation cohorts. There were 432 patients in the training cohort, 285 in the prospective internal validation cohort, and 286, 189, and 135 in three external validation cohorts, respectively. The score was calculated using total bilirubin, α-fetoprotein (AFP), tumor diameter, and satellite lesions. The EHBH-PVTT score differentiated two groups of patients (≤/>3 points) with distinct long-term prognoses (median overall survival [OS], 17.0 vs. 7.9 months; P < 0.001). Predictive accuracy, as determined by the area under the time-dependent receiver operating characteristic curves (AUCs; 0.680-0.721), was greater than that of the other commonly used staging systems for HCC and PVTT. Conclusion: The EHBH-PVTT scoring system was more accurate in predicting the prognosis of HCC patients with PVTT than other staging systems after LR. It selected appropriate HCC patients with PVTT limited to a first-order branch of the MPV or above for LR. It can be used to supplement the other HCC staging systems.

The impact of portal vein tumor thrombus on long-term survival after liver resection for primary hepatic malignancy.

BACKGROUND: The aim of this study was to evaluate the effect of portal vein tumor thrombus (PVTT) on the prognosis of patients undergoing liver resection (LR) for primary liver malignancies (PLC). METHODS: The recurrence-free survival (RFS) and overall survival (OS) for patients undergoing LR with and without PVTT for three primary liver malignancies, including hepatocellular carcinoma (HCC), intrahepatic cholangiocarcinoma (ICC) and hepato-cholangio carcinoma (CHC) were compared using the Kaplan-Meier method and Cox regression analysis. RESULTS: In total, 3775 patients with PLC who underwent LR were included in this study. The incidence of PVTT in patients undergoing LR with HCC, IHC and CHC were 46%, 20%, and 17%, respectively. The median RFS and OS were significantly better for patients with HCC as compared to ICC or CHC (16 vs 11 vs 13 months; 21 vs 16 vs 18 months, respectively; P < 0.001). However, the presence of PVTT resulted in similarly poor RFS and OS in these 3 subgroups of patients (9 vs 8 vs 8 months, P = 0.062; 14 vs 13 vs 12 months, respectively, P = 0.052). CONCLUSION: Although the prognosis of patients with PLC varied by histological subtype, once PVTT occurred, survival outcomes after LR were similarly poor across all three subgroups.

An Eastern Hepatobiliary Surgery Hospital Microvascular Invasion Scoring System in Predicting Prognosis of Patients with Hepatocellular Carcinoma and Microvascular Invasion After R0 Liver Resection: A Large-Scale, Multicenter Study.

BACKGROUND: Microvascular invasion (MVI) is associated with poor postoperative survival outcomes in patients with hepatocellular carcinoma (HCC). An Eastern Hepatobiliary Surgery Hospital (EHBH) MVI scoring system was established to predict prognosis in patients with HCC with MVI after R0 liver resection (LR) and to supplement the most commonly used classification systems. MATERIALS AND METHODS: Patients with HCC with MVI who underwent R0 LR as an initial therapy were included. The EHBH-MVI score was developed from a retrospective cohort from 2003 to 2009 to form the training cohort. The variables associated with overall survival (OS) on univariate analysis were subsequently investigated using the log-rank test, and the EHBH-MVI score was developed using the Cox regression model. It was validated using an internal prospective cohort from 2011 to 2013 as well as three independent external validation cohorts. RESULTS: There were 1,033 patients in the training cohort; 322 patients in the prospective internal validation cohort; and 493, 282, and 149 patients in the three external validation cohorts, respectively. The score was developed using the following factors: α-fetoprotein level, tumor encapsulation, tumor diameter, hepatitis B e antigen positivity, hepatitis B virus DNA load, tumor number, and gastric fundal/esophageal varicosity. The score differentiated two groups of patients (≤4, >4 points) with distinct long-term prognoses outcomes (median OS, 55.8 vs. 19.6 months; p < .001). The predictive accuracy of the score was greater than the other four commonly used staging systems for HCC. CONCLUSION: The EHBH-MVI scoring system was more accurate in predicting prognosis in patients with HCC with MVI after R0 LR than the other four commonly used staging systems. The score can be used to supplement these systems. IMPLICATIONS FOR PRACTICE: Microvascular invasion (MVI) is a major determinant of survival outcomes after curative liver resection for patients with hepatocellular carcinoma (HCC). Currently, there is no scoring system aiming to predict prognosis of patients with HCC and MVI after R0 liver resection (LR). Most of the widely used staging systems for HCC do not use MVI as an independent risk factor, and they cannot be used to predict the prognosis of patients with HCC and MVI after surgery. In this study, a new Eastern Hepatobiliary Surgery Hospital (EHBH) MVI scoring system was established to predict prognosis of patients with HCC and MVI after R0 LR. Based on the results of this study, postoperative adjuvant therapy may be recommended for patients with HCC and MVI with an EHBH-MVI score >4. This score can be used to supplement the currently used HCC classifications to predict postoperative survival outcomes in patients with HCC and MVI.

Association of Preoperative Hypercoagulability with Poor Prognosis in Hepatocellular Carcinoma Patients with Microvascular Invasion After Liver Resection: A Multicenter Study.

BACKGROUND: Microvascular invasion (MVI) predicts poor prognosis in patients with hepatocellular carcinoma (HCC). HCC patients with hypercoagulability are prone to develop thrombosis; however, the relationship between preoperative coagulability state, as reflected by the international normalized ratio (INR) level, and MVI remains unclear. METHODS: From January 2009 to December 2012, HCC patients who underwent R0 liver resection (LR) from four cancer centers entered into this study. The overall survival (OS) and recurrence-free survival (RFS) rates were compared using the Kaplan-Meier method and Cox regression analysis. RESULTS: Of the 2509 HCC patients who were included into this study, 1104 were found to have MVI in the resected specimens. These patients were divided into the low (n = 151), normal (n = 796), and high (n = 157) INR subgroups based on the preoperative INR levels. The low INR subgroup had a significantly higher incidence of MVI than the normal or high INR subgroups (61.6% vs. 41.6% vs. 44.6%; p < 0.001). HCC patients with MVI were significantly more likely to have a low preoperative INR level (p < 0.001); the INR level (p < 0.001) was an independent risk factor of OS and RFS. HCC patients with MVI in the low INR subgroup had significantly worse RFS and OS than the normal or high INR subgroups (median RFS 13.5 vs. 20.2 vs. 21.6 months, p < 0.001; median OS 35.5 vs. 59.5 vs. 57.0 months, p < 0.001). CONCLUSIONS: Preoperative hypercoagulability was associated with poor long-term prognosis in HCC patients with MVI after R0 LR.

Postoperative Adjuvant Transarterial Chemoembolization Improves Outcomes of Hepatocellular Carcinoma Associated with Hepatic Vein Invasion: A Propensity Score Matching Analysis.

BACKGROUND: Vascular invasion is a major determinant of survival outcomes after curative resection for hepatocellular carcinoma (HCC) patients. This study was designed to investigate the efficacy of postoperative adjuvant transarterial chemoembolization (PA-TACE) in patients with HCC with hepatic vein tumor thrombus (HVTT). METHODS: Data from patients who underwent LR for HCC with HVTT at the Eastern Hepatobiliary Surgery Hospital were retrospectively analyzed. The survival outcomes for patients who underwent PA-TACE after LR were compared with those who underwent LR alone. Propensity score matching (PSM) analysis was performed to match patients in a ratio of 1:1. RESULTS: All included 319 patients who underwent LR for HCC with HVTT, 134 underwent LR alone (the LR group), and 185 patients underwent in adjuvant TACE (the PA-TACE group). PSM matched 107 patients in two groups. The overall survival (OS) and recurrence-free survival (RFS) were significantly better for patients in the PA-TACE group than the LR group (for OS: before PSM, P < 0.001; after PSM, P = 0.004; for RFS: before PSM, P < 0.001; after PSM, P = 0.013), respectively. On subgroup analysis, equivalent acceptable results were obtained in patients with peripheral HVTT (pHVTT) and major HVTT (mHVTT). However, PA-TACE resulted in no survival benefits for patients when the HVTT had extended to the inferior vena cava (IVCTT). CONCLUSIONS: PA-TACE was associated with significantly better survival outcomes than LR alone for patients with HCC and HVTT (pHVTT and mHVTT). There was no survival benefits in patients whose HVTT had extended to form IVCTT.

Liver resection versus transcatheter arterial chemoembolization for the treatment of patients with hepatocellular carcinoma and hepatic vein or inferior vena cava tumor thrombus: A propensity score matching analysis.

AIM: Because of the rarity of hepatic vein tumor thrombus (HVTT) in patients with hepatocellular carcinoma (HCC), little is known about HVTT. Thus, the survival benefit of liver resection (LR) versus transcatheter arterial chemoembolization (TACE) for HCC patients with HVTT or inferior vena cava tumor thrombus (IVCTT) remains controversial. We aimed to explore the survival benefits of LR versus TACE for the treatment of these patients. METHODS: From 2012 to 2016, a total of 276 patients with HVTT or IVCTT who underwent liver resection or TACE were enrolled in this study. Patients in the LR group were matched at a 1:1 ratio with patients treated with TACE as an initial treatment (TACE group). Clinical characteristics, overall survival, and disease-free survival were analyzed. RESULTS: The median survival time in the LR group was 4.7 months longer than that in the TACE group before PSM (19.4 vs. 14.7 months, P = 0.006) and 6.9 months longer than that in the TACE group after PSM (20.9 vs. 14.0 months, P = 0.019). The median disease-free survival time in the LR group was 3.2 months longer than that in the TACE group before PSM (12.3 vs. 9.1 months, P = 0.038) and 5.8 months longer than that in the TACE group after PSM (13.0 vs. 7.2 months, P = 0.011). CONCLUSION: Liver resection provides a good prognosis for HCC patients with HVTT or IVCTT compared with patients undergoing TACE, and coexistence with portal vein tumor thrombus is the most important factor related to survival.

Effect of microvascular invasion on the postoperative long-term prognosis of solitary small HCC: a systematic review and meta-analysis.

BACKGROUND: The effect of microvascular invasion (MVI) on the postoperative long-term prognosis of solitary small hepatocellular carcinoma remains controversial. We compared the long-term outcomes of MVI-positive and MVI-negative groups of patients with solitary small hepatocellular carcinoma. METHODS: The PubMed, EMBASE, Cochrane Library, VIP, Wan Fang, and Sino Med databases were systematically searched to compare the long-term outcomes of MVI-positive and MVI-negative groups of patients with solitary small hepatocellular carcinoma from inception to November 1, 2018. The study outcomes, including overall survival (OS) and disease-free survival (DFS), were extracted independently by two authors. RESULTS: Fourteen studies involving 3033 patients were evaluated. A meta-analysis of all 14 studies suggested that the OS of the MVI-positive group was significantly worse than that of the MVI-negative group (HR = 2.39, 95% CI = 2.02-2.84, I2 = 22.8%; P < 0.001). Twelve studies were included in the meta-analysis of DFS, and MVI showed a worse prognosis (HR = 1.79, 95% CI = 1.59-2.02, I2 = 25.3%; P < 0.001). Subgroup analysis demonstrated that MVI still showed a negative effect on the long-term OS and DFS of patients with solitary small HCC measuring up to 2 cm, 3 cm, or 5 cm. CONCLUSION: Microvascular invasion was a risk factor for poorer prognosis for solitary small hepatocellular carcinoma.

Postoperative adjuvant sorafenib improves survival outcomes in hepatocellular carcinoma patients with microvascular invasion after R0 liver resection: a propensity score matching analysis.

BACKGROUND: Microvascular invasion (MVI) is a major determinant of survival outcome for hepatocellular carcinoma (HCC). This study aimed to investigate the efficacy of postoperative adjuvant Sorafenib (PA-Sorafenib) in HCC patients with MVI after R0 liver resection (LR). METHODS: The data of patients who underwent R0 LR for HCC with histologically confirmed MVI at the Eastern Hepatobiliary Surgery Hospital were retrospectively analyzed. The survival outcomes for patients who underwent PA-Sorafenib were compared with those who underwent R0 LR alone. Propensity score matching (PSM) analysis was performed. RESULTS: 728 HCC patients had MVI in the resected specimens after R0 resection, with 581 who underwent LR alone and 147 patients who received in additional adjuvant sorafenib. PSM matched 113 patients in each of these two groups. The overall survival (OS) and recurrence free survival (RFS) were significantly better for patients in the PA-sorafenib group (for OS: before PSM, P = 0.003; after PSM, P = 0.007), (for RFS: before PSM, P = 0.029; after PSM, P = 0.001), respectively. Similar results were obtained in patients with BCLC 0-A, BCLC B and Child-Pugh A stages of disease. CONCLUSIONS: PA-Sorafenib was associated with significantly better survival outcomes than LR alone for HCC patients with MVI.

Berberine hydrochloride counteracts enhanced IL-8 expression induced by SN 38 in AGS cells.

IL-8 over-expression could enhance cancer metastasis. In present study, berberine hydrochloride (BER) triggered proliferative inhibition and G2/M arrest in AGS cells, down-regulated protein expression of cyclin B1, Bcl-2, up-regulated expression of p21, p53 and cleaved caspase 3, but showed no effect on protein expression of CHOP, Bip, and caspase 4. BER could down-regulate the enhanced IL-8 expression through down-regulating ERK1/2 and p38 MAPK over-activation induced by SN 38. The increased IL-8 mediated adhesive ability of AGS cells to HUVECs induced by SN 38, could be reduced by BER. Thus, BER could reduce the side-effect of SN 38 in clinic.

Robo1 promotes angiogenesis in hepatocellular carcinoma through the Rho family of guanosine triphosphatases' signaling pathway.

Robo1 is a member of the Robo immunoglobulin superfamily of proteins, and it plays an important role in angiogenesis and cancer. In this study, we investigate the role of roundabout 1 (Robo1) in tumor angiogenesis in hepatocellular carcinoma (HCC). Firstly, the relationship between Robo1 expression on tumors and patient's survival and endothelial cells in tumor blood vessels and patient's survival was studied. Secondly, Robo1 was overexpressed or knocked down in human umbilical vein endothelial cells (HUVECs). Cell proliferation, motility, and tube formation were compared in HUVEC with different Robo1 expression. Also, HUVECs with different Robo1 expression were mixed with HCCLM3 and HepG2 hepatoma cells and then implanted in a nude mouse model to examine the effects of Robo1 in endothelial cells on tumor growth and angiogenesis. Cell motility-related molecules were studied to investigate the potential mechanism how Robo1 promoted tumor angiogenesis in HCC. The disease-free survival of the patients with high Robo1 expression in tumoral endothelial cells was significantly shorter than that of those with low expression (P = 0.021). Overexpression of Robo1 in HUVECs resulted in increased proliferation, motility, and tube formation in vitro. In the implanted mixture of tumor cells and HUVECs with an increased Robo1 expression, tumor growth and microvessel density were enhanced compared with controls. Robo1 promoted cell division cycle 42 (Cdc42) expression in HUVECs, and a distorted actin cytoskeleton in HUVECs was observed when Robo1 expression was suppressed. In conclusion, Robo1 promoted angiogenesis in HCC mediated by Cdc42.

DNA-PKcs deficiency sensitizes the human hepatoma HepG2 cells to cisplatin and 5-fluorouracil through suppression of the PI3K/Akt/NF-κB pathway.

The aim of the present study was to investigate the effects of DNA-PKcs deficiency on the chemosensitivity of human hepatoma HepG2 cells to cisplatin (CDDP) and 5-fluorouracil (5-Fu), and to explore the underlying molecular mechanism. After transfection with DNA-PKcs siRNA or control siRNA, HepG2 cells were exposed to combination treatment of CDDP and 5-Fu. The cell viability, DNA damage, cell apoptosis, intracellular reactive oxygen species and glutathione (GSH) level, expression of apoptosis related proteins, activity of phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) pathway, and nuclear factor-κB (NF-κB) pathways were assessed. The combination of CDDP and 5-Fu had a synergistic cytotoxic effect in HepG2 cells in terms of the cell viability, DNA damage, apoptosis, and oxidative stress level. DNA-PKcs siRNA could sensitize the HepG2 cells to the combined treatment. DNA-PKcs suppression further reduced the Akt phosphorylation level and Bcl-2 expression in HepG2 cells exposed to CDDP and 5-Fu, but enhanced the expression of pro-apoptotic proteins p53 and caspase-3. Moreover, CDDP could inhibit the transcriptional activity of NF-κB through degradation of IkB-α, while 5-Fu alone seemed in some extent increases the NF-κB activity. The combined treatment with CDDP and 5-Fu resulted in significantly decrease of the transcriptional activity of NF-κB, which was further aggravated by DNA-PKcs siRNA treatment. In conclusion, DNA-PKcs suppression had complementary effects in combination with CDDP and 5-Fu treatment in HepG2 cells, which was associated with suppression of NF-κB signaling pathway cascade, activation of caspase-3 and p53, as well as down-regulation of Bcl-2 and GSH.

Decoupling the dynamic mechanism revealed by FGFR2 mutation-induced population shift.

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.

MiR-146a enhances angiogenic activity of endothelial cells in hepatocellular carcinoma by promoting PDGFRA expression.

Endothelial cells (ECs) are critical for angiogenesis, and microRNAs play important roles in this process. We investigated the regulatory role of microRNAs in ECs of hepatocellular carcinoma (HCC) by examining the microRNA expression profile of human umbilical vein endothelial cells (HUVECs) in the absence or presence of human HCC cells, and identified miR-146a as the most highly upregulated microRNA. Furthermore, we revealed that miR-146a promoted the expression of platelet-derived growth factor receptor α (PDGFRA) in HUVECs, and this process was mediated by BRCA1. Overexpression of PDGFRA in the ECs of HCC tissues was associated with microvascular invasion and predicted a poorer prognosis. These results suggest that miR-146a plays a key role in regulating the angiogenic activity of ECs in HCC through miR-146a-BRCA1-PDGFRA pathway. MiR-146a and PDGFRA may emerge as potential anti-angiogenic targets on ECs for HCC therapy.

Antiangiogenic therapy promoted metastasis of hepatocellular carcinoma by suppressing host-derived interleukin-12b in mouse models.

Antiangiogenic therapy, specially sorafenib, has become the standard of care for patients with advanced hepatocellular carcinoma (HCC), however, the improvement in survival time is not satisfactory. Previous studies have found that, in some circumstances, antiangiogenic therapy promoted tumor metastasis and the mechanistic studies were mainly focus on cancer-cell-autonomous manners. In two experimental metastasis models with tail-vein injection with hepatoma cells and an orthotopic HCC mouse model, we found that pretreatment with two vascular endothelial growth factor receptor (VEGFR) inhibitors, sunitinib and sorafenib, facilitated tumor cell survival in blood stream and promoted lung metastasis from tumors that were subsequently incubated after drug discontinuation, indicating that host response joined into the pro-metastatic effects. An antibody microarray identified that interleukin (IL)-12b was decreased in the peripheral blood of the mice treated with the two VEGFR inhibitors. IL-12b suppression in macrophages and dendritic cells from host organs was found to play a crucial role in treatment-induced metastasis. Supplement with recombinant mouse IL-12b or restoration of IL-12b expression in the host by zoledronic acid, which was previously reported to enhance IL-12 expression in vitro and in vivo, alleviated the metastasis-promoting effects of sunitinib and sorafenib. These studies suggest that host response to VEGFR inhibitors facilitates HCC metastasis and restoration of IL-12b expression could translate into clinical benefits.