LGR4 and LGR5 form distinct homodimers that only LGR4 complexes with RNF43/ZNRF3 to provide high affinity binding of R-spondin ligands.

LGR4 and LGR5 are two homologous receptors that potentiate Wnt/ß-catenin signaling in response to R-spondin (RSPO) ligands. The RSPO and LGR4 complex binds to and inhibits activities of two related E3 ubiquitin ligases, RNF43 and ZNRF3, and thus protects Wnt receptors from the E3 ligase-mediated degradation. The RSPO and LGR5 complex, however, does not interact with the E3 ligases, and the structural basis of this difference remained unknown. Here we examined the affinities of monovalent and bivalent RSPO ligands in binding to LGR4, RNF43/ZNRF3, and LGR5 in whole cells and found unique features among the receptors and E3 ligases. Monovalent RSPO2 furin domain had much lower affinity in binding to LGR4 or RNF43/ZNRF3 than the bivalent form. In contrast, monovalent and bivalent forms had nearly identical affinity in binding to LGR5. Co-expression of ZNRF3 with LGR4 led to much higher binding affinity of the monovalent form whereas co-expression of ZNRF3 with LGR5 had no effect on the affinity. These results suggest that LGR4 and RNF43/ZNRF3 form a 2:2 dimer that accommodates bivalent binding of RSPO whereas LGR5 forms a homodimer that does not. Structural models are proposed to illustrate how RSPOs bind to LGR4, RNF43/ZNRF3, and LGR5 in whole cells.

Genetic polymorphisms and phylogenetic characteristics of Tibeto-Burman-speaking Lahu population from southwest China based on 41 Y-STR loci.

BACKGROUND: Male sex-linked Y-chromosome short tandem repeats (Y-STRs) have been widely used in forensic cases and population genetics research. At present, the forensic-related Y-STR data in the Chinese Lahu population are still poorly understood. AIM: To enrich the available Y-STR data of this Chinese minority population and investigate its phylogenetic relationships with other reported populations. SUBJECTS AND METHODS: The genetic polymorphisms of 41 Y-STR loci were analysed in 299 unrelated healthy Lahu male individuals from Southwest China. Phylogenetic analyses were performed by multidimensional scaling analysis and neighbor-joining phylogenetic tree construction. RESULTS: A total of 379 alleles were observed at the 41 Y-STR loci. The allele frequencies ranged from 0.0033 to 0.9666. The genetic diversity values ranged from 0.0653 to 0.9072. A total of 254 different haplotypes of the 41 Y-STR loci were observed in 299 individuals. The values of haplotype diversity, haplotype match probability, and discrimination capacity were 0.9987, 0.0047, and 0.8495, respectively. The phylogenetic analysis indicated that the Tibeto-Burman-speaking Lahu population showed a close genetic relationship with the Yunnan Yi population. CONCLUSIONS: The haplotype data of the present study can enrich the forensic databases of this Chinese minority population and will be useful for population genetics and forensic DNA application.

Effect of NR5A2 inhibition on pancreatic cancer stem cell (CSC) properties and epithelial-mesenchymal transition (EMT) markers.

NR5A2 (aka LRH-1) has been identified as a pancreatic cancer susceptibility gene with missing biological link. This study aims to demonstrate expression and potential role of NR5A2 in pancreatic cancer. NR5A2 expression was quantified in resected pancreatic ductal adenocarcinomas and the normal adjacent tissues of 134 patients by immunohistochemistry. The intensity and extent of NR5A2 staining was quantified and analyzed in association with overall survival (OS). The impact of NR5A2 knockdown on pancreatic cancer stem cell (CSC) properties and epithelial-mesenchymal transition (EMT) markers was examined in cancer cells using RT-PCR and Western Blot. NR5A2 was overexpressed in pancreatic tumors, the IHC-staining H score (mean ± SE) was 96.4 ± 8.3 in normal versus 137.9 ± 8.2 in tumor tissues (P < 0.0001). Patients with a higher NR5A2 expression had a median survival time 18.4 months compared to 23.7 months for those with low IHC H scores (P = 0.019). The hazard ratio of death (95% confidence interval) was 1.60 (1.07-2.41) after adjusting for disease stage and tumor grade (P = 0.023). NR5A2 was highly expressed in pancreatic cancer sphere forming cells. NR5A2-inhibition by siRNA was associated with reduced sphere formation and decreased levels of CSCs markers NANOG, OCT4, LIN28B, and NOTCH1. NR5A2 knockdown also resulted in reduced expression of FGB, MMP2, MMP3, MMMP9, SNAIL, and TWIST, increased expression of epithelial markers E-cadherin and ß-catenin, and a lower expression of mesenchymal marker Vimentin. Taken together, our findings suggest that NR5A2 could play a role in CSC stemness and EMT in pancreatic cancer, which may contribute to the worse clinical outcome.

Biliary cancer: Utility of next-generation sequencing for clinical management.

BACKGROUND: Biliary tract cancers (BTCs) typically present at an advanced stage, and systemic chemotherapy is often of limited benefit. METHODS: Hybrid capture-based comprehensive genomic profiling (CGP) was performed for 412 intrahepatic cholangiocarcinomas (IHCCAs), 57 extrahepatic cholangiocarcinomas (EHCCAs), and 85 gallbladder carcinomas (GBCAs). The mutational profile was correlated with the clinical outcome of standard and experimental therapies for 321 patients. Clinical variables, detected mutations, and administered therapies were correlated with overall survival (OS) in a Cox regression model. RESULTS: The most frequent genetic aberrations (GAs) observed were tumor protein 53 (TP53; 27%), cyclin-dependent kinase inhibitor 2A/B (CDKN2A/B; 27%), KRAS (22%), AT-rich interactive domain-containing protein 1A (ARID1A; 18%), and isocitrate dehydrogenase 1 (IDH1; 16%) in IHCCA; KRAS (42%), TP53 (40%), CDKN2A/B (17%), and SMAD4 (21%) in EHCCA; and TP53 (59%), CDKN2A/B (19%), ARID1A (13%), and ERBB2 (16%) in GBCA. Fibroblast growth factor receptor (FGFR; 11%) and IDH mutations (20%) were mostly limited to IHCCA but appeared to be mutually exclusive. In the IHCCA group, TP53 and KRAS mutations were associated significantly with poor OS, whereas FGFR2 mutations were associated with improved OS (P = .001), a younger age at onset, and female sex. IDH1/2 mutations were not prognostic. In a multivariate model, the effects of TP53 and FGFR GAs remained significant (P < .05). Patients with FGFR GAs had superior OS with FGFR-targeted therapy versus standard regimens (P = .006). Targeted therapy in IHCCA was associated with a numerical OS improvement (P = .07). CONCLUSIONS: This is the largest clinically annotated data set of BTC cases with CGP and indicates the potential of CGP for improving outcomes. CGP should be strongly considered in the management of BTC patients. Cancer 2016;122:3838-3847. © 2016 American Cancer Society.

BRCA-associated protein 1 mutant cholangiocarcinoma: an aggressive disease subtype.

BACKGROUND: BRCA-associated protein 1, an enzyme encoded by the BAP1 gene, is commonly mutated in uveal melanoma, mesothelioma, and renal cancers. Tumors with BAP1 mutation follow an aggressive course. BAP1 mutations have also been observed in cholangiocarcinoma (CCA). The clinical phenotype of BAP1 mutant CCA may yield useful prognostic and therapeutic information but has not been defined. METHODS: The records of CCA patients who underwent next-generation sequencing (NGS) were reviewed, and data on clinical, histopathological, genetic, and radiological features; response to therapy; time to progression; and survival were analyzed. RESULTS: Twenty-two cases of BAP1-mutation associated CCA were diagnosed from January 1, 2009, to February 1, 2015, at our center. Twenty patients had intrahepatic CCA and two had extrahepatic CCA. Tumor sizes (largest dimension) ranged from 2 to 16 cm (mean, 8.5 cm). Twelve patients had tumors that were poorly differentiated. Majority of the patients had advanced disease at presentation and 13 had bone metastases. Thirteen patients (59%) experienced rapidly progressive disease following primary therapy (chemotherapy or surgical resection). The mean time to tumor progression was 3.8 months after the first line chemotherapy. CONCLUSIONS: BAP1 mutation in CCA may be associated with aggressive disease and poor response to standard therapies. Therefore, BAP1-targeted therapies need to be investigated.

RNA sequencing-based analysis of gallbladder cancer reveals the importance of the liver X receptor and lipid metabolism in gallbladder cancer.

Gallbladder cancer (GBC) is an aggressive malignancy. Although surgical resection may be curable, most patients are diagnosed at an advanced unresectable disease stage. Cholelithiasis is the major risk factor; however the pathogenesis of the disease, from gallstone cholecystitis to cancer, is still not understood. To understand the molecular genetic underpinnings of this cancer and explore novel therapeutic targets for GBC, we examined the key genes and pathways involved in GBC using RNA sequencing. We performed gene expression analysis of 32 cases of surgically-resected GBC along with normal gallbladder tissue controls. We observed that 519 genes were differentially expressed between GBC and normal GB mucosal controls. The liver X receptor (LXR)/retinoid X receptor (RXR) and farnesoid X receptor (FXR) /RXR pathways were the top canonical pathways involved in GBC. Key genes in these pathways, including SERPINB3 and KLK1, were overexpressed in GBC, especially in female GBC patients. Additionally, ApoA1 gene expression suppressed in GBC as compared with normal control tissues. LXR and FXR genes, known to be important in lipid metabolism also function as tumor suppressors and their down regulation appears to be critical for GBC pathogenesis. LXR agonists may have therapeutic value and as potential therapeutic targets.

HER2/neu-directed therapy for biliary tract cancer.

BACKGROUND: Biliary cancers are highly aggressive tumors that are often diagnosed an advanced disease stage and have a poor outcome with systemic therapy. Recent efforts towards molecular characterization have identified a subset of biliary patients that have HER2/neu amplification or mutation. HER2/neu amplification is associated with response to HER2/neu-directed therapy in breast and gastric cancers. However, the efficacy of HER2/neu-targeted therapy in biliary cancers is unknown. PATIENTS AND METHODS: We retrospectively reviewed cases of advanced gallbladder cancer and cholangiocarcinoma with HER2/neu genetic aberrations or protein overexpression who received HER2/neu-directed therapy between 2007 and 2014. Clinical data were retrieved from medical records, and imaging studies were independently reviewed. RESULTS: Nine patients with gallbladder cancer and five patients with cholangiocarcinoma had received HER2/neu-directed therapy (trastuzumab, lapatinib, or pertuzumab) during the study period. In the gallbladder cancer group, HER2/neu gene amplification or overexpression was detected in eight cases. These patients experienced disease stability (n = 3), partial response (n = 4), or complete response (n = 1) with HER2/neu-directed therapy. One patient had HER2/neu mutation and experienced a mixed response after lapatinib therapy. The duration of response varied from 8+ to 168 weeks (median 40 weeks), and three patients are still on therapy. One patient developed HER2/neu amplification as a secondary event after FGFR-directed therapy for FGF3-TACC3 gene fusion. The cholangiocarcinoma cases treated in this series had a higher proportion of HER2/neu mutations, and no radiological responses were seen in these patients despite HER2/neu-directed therapy. CONCLUSIONS: HER2/neu blockade is a promising treatment strategy for gallbladder cancer patients with gene amplification and deserves further exploration in a multi-center study.

LLL12, a novel small inhibitor targeting STAT3 for hepatocellular carcinoma therapy.

The constitutive activation of signal transducer and activator of transcription 3 (STAT3) is frequently detected in clinical incidences of hepatocellular carcinoma (HCC) but not in normal human hepatocytes. STAT3 signaling plays pivotal roles in angiogenesis, survival, metastasis, and growth of HCC. Recent evidence suggests that the blockade of aberrant STAT3 pathways can be exploited as a therapeutic strategy for HCC. We have developed the novel small molecular STAT3 inhibitor LLL12 on the basis of curcumin structure using computer-aided rational design. LLL12 has shown antitumor activity in various solid tumors including breast, brain, pancreatic cancer, and glioblastoma in vitro and in vivo. In this study, we hypothesized LLL12 inhibits STAT3 phosphorylation at tyrosine 705 (Y705) in HCC and show antitumor activity in HCC in vitro and in vivo. Our results show that LLL12 selectively inhibited HCC cell proliferation and induced apoptosis in SNU387, SNU398, SNU449, and Hep3B HCC cells in vitro. Furthermore, LLL12 at 5 mg/kg/day significantly inhibited the growth of SNU398 xenografts in nude mice. Collectively, our results indicate that LLL12 could be used to target STAT3 for the effective prevention or treatment of HCC.

Mutation profiling in cholangiocarcinoma: prognostic and therapeutic implications.

BACKGROUND: Cholangiocarcinoma (CCA) is clinically heterogeneous; intra and extrahepatic CCA have diverse clinical presentations. Next generation sequencing (NGS) technology may identify the genetic differences between these entities and identify molecular subgroups for targeted therapeutics. METHODS: We describe successful NGS-based testing of 75 CCA patients along with the prognostic and therapeutic implications of findings. Mutation profiling was performed using either a) NGS panel of hotspot regions in 46 cancer-related genes using a 318-chip on Ion PGM Sequencer or b) Illumina HiSeq 2000 sequencing platform for 3,769 exons of 236 cancer-related genes plus 47 introns from 19 genes to an average depth of 1000X. Clinical data was abstracted and correlated with clinical outcome. Patients with targetable mutations were referred to appropriate clinical trials. RESULTS: There were significant differences between intrahepatic (n = 55) and extrahepatic CCA (n = 20) in regard to the nature and frequency of the genetic aberrations (GAs). IDH1 and DNA repair gene alterations occurred more frequently in intrahepatic CCA, while ERBB2 GAs occurred in the extrahepatic group. Commonly occurring GAs in intrahepatic CCA were TP53 (35%), KRAS (24%), ARID1A (20%), IDH1 (18%), MCL1 (16%) and PBRM1 (11%). Most frequent GAs in extrahepatic CCA (n = 20) were TP53 (45%), KRAS (40%), ERBB2 (25%), SMAD4 (25%), FBXW7 (15%) and CDKN2A (15%). In intrahepatic CCA, KRAS, TP53 or MAPK/mTOR GAs were significantly associated with a worse prognosis while FGFR GAs correlated with a relatively indolent disease course. IDH1 GAs did not have any prognostic significance. GAs in the chromatin modulating genes, BAP1 and PBRM1 were associated with bone metastases and worse survival in extrahepatic CCA. Radiologic responses and clinical benefit was noted with EGFR, FGFR, C-met, B-RAF and MEK inhibitors. CONCLUSION: There are significant genetic differences between intra and extrahepatic CCA. NGS can potentially identify disease subsets with distinct prognostic and therapeutic implications.

The UPF1 RNA surveillance gene is commonly mutated in pancreatic adenosquamous carcinoma.

Pancreatic adenosquamous carcinoma (ASC) is an enigmatic and aggressive tumor that has a worse prognosis and higher metastatic potential than its adenocarcinoma counterpart. Here we report that ASC tumors frequently harbor somatically acquired mutations in the UPF1 gene, which encodes the core component of the nonsense-mediated RNA decay (NMD) pathway. These tumor-specific mutations alter UPF1 RNA splicing and perturb NMD, leading to upregulated levels of NMD substrate mRNAs. UPF1 mutations are, to our knowledge, the first known unique molecular signatures of pancreatic ASC.

Molecular characterization of gallbladder cancer using somatic mutation profiling.

Gallbladder cancer is relatively uncommon, with a high incidence in certain geographic locations, including Latin America, East and South Asia, and Eastern Europe. Molecular characterization of this disease has been limited, and targeted therapy options for advanced disease remain an open area of investigation. In the present study, surgical pathology obtained from resected gallbladder cancer cases (n = 72) was examined for the presence of targetable, somatic mutations. All cases were formalin fixed and paraffin embedded (FFPE). Two approaches were used: (a) mass spectroscopy-based profiling for 159 point ("hot spot") mutations in 33 genes commonly involved in solid tumors and (b) next-generation sequencing (NGS) platform that examined the complete coding sequence of in 182 cancer-related genes. Fifty-seven cases were analyzed for hot spot mutations; and 15, for NGS. Fourteen hot spot mutations were identified in 9 cases. Of these, KRAS mutation was significantly associated with poor survival on multivariate analysis. Other targetable mutations included PIK3CA (n = 2) and ALK (n = 1). On NGS, 26 mutations were noted in 15 cases. TP53 and PI3 kinase pathway (STK11, RICTOR, TSC2) mutations were common. One case had FGF10 amplification, whereas another had FGF3-TACC gene fusion, not previously described in gallbladder cancer. In conclusion, somatic mutation profiling using archival FFPE samples from gallbladder cancer is feasible. NGS, in particular, may be a useful platform for identifying novel mutations for targeted therapy.

[Effect of Meisoindigo on Wnt signal pathway in K562 and HL-60 cells].

The aim of this study was to investigate the effect of meisoindigo on Wnt signal pathway in K562 cells and HL-60 cells and its possible regulatory mechanism. RT-PCR and Western blot assay were used to detect the expression of GSK-3beta and its downstream associated genes as well as proteins expression respectively. The results showed that the meisoindigo could inhibit the phosphorylation of GSK-3beta and decreased beta-catenin and c-myc genes expression in HL-60 cells, but did not significantly affect the two gene expression in K562 cells. Meisoindigo slightly increased the expression of GSK-3beta protein in HL-60 cells, obviously decreased the expression of p-GSK-3beta and c-MYC proteins in K562 cells and HL-60 cells, while meisoindigo did not affect the expression of beta-catenin in K562 cells significantly, but could decrease the expression of beta-catenin in HL-60 cells. It is concluded that the meisoindigo can affect the Wnt signal pathway through inhibiting the GSK-3beta expression and down-regulating the beta-catenin and c-MYC protein expression, which play an important role in the treatment for chronic myeloid leukemia.

Novel STAT3 phosphorylation inhibitors exhibit potent growth-suppressive activity in pancreatic and breast cancer cells.

The constitutive activation of signal transducer and activator of transcription 3 (STAT3) is frequently detected in most types of human cancer where it plays important roles in survival, drug resistance, angiogenesis, and other functions. Targeting constitutive STAT3 signaling is thus an attractive therapeutic approach for these cancers. We have recently developed novel small-molecule STAT3 inhibitors, known as FLLL31 and FLLL32, which are derived from curcumin (the primary bioactive compound of turmeric). These compounds are designed to bind selectively to Janus kinase 2 and the STAT3 Src homology-2 domain, which serve crucial roles in STAT3 dimerization and signal transduction. Here we show that FLLL31 and FLLL32 are effective inhibitors of STAT3 phosphorylation, DNA-binding activity, and transactivation in vitro, leading to the impediment of multiple oncogenic processes and the induction of apoptosis in pancreatic and breast cancer cell lines. FLLL31 and FLLL32 also inhibit colony formation in soft agar and cell invasion and exhibit synergy with the anticancer drug doxorubicin against breast cancer cells. In addition, we show that FLLL32 can inhibit the induction of STAT3 phosphorylation by IFNalpha and interleukin-6 in breast cancer cells. We also show that administration of FLLL32 can inhibit tumor growth and vascularity in chicken embryo xenografts as well as substantially reduce tumor volumes in mouse xenografts. Our findings highlight the potential of these new compounds and their efficacy in targeting pancreatic and breast cancers that exhibit constitutive STAT3 signaling.

A novel small molecule, LLL12, inhibits STAT3 phosphorylation and activities and exhibits potent growth-suppressive activity in human cancer cells.

Constitutive activation of signal transducer and activator of transcription 3 (STAT3) signaling is frequently detected in cancer, promoting its emergence as a promising target for cancer treatment. Inhibiting constitutive STAT3 signaling represents a potential therapeutic approach. We used structure-based design to develop a nonpeptide, cell-permeable, small molecule, termed as LLL12, which targets STAT3. LLL12 was found to inhibit STAT3 phosphorylation (tyrosine 705) and induce apoptosis as indicated by the increases of cleaved caspase-3 and poly (ADP-ribose) polymerase in various breast, pancreatic, and glioblastoma cancer cell lines expressing elevated levels of STAT3 phosphorylation. LLL12 could also inhibit STAT3 phosphorylation induced by interleukin-6 in MDA-MB-453 breast cancer cells. The inhibition of STAT3 by LLL12 was confirmed by the inhibition of STAT3 DNA binding activity and STAT3-dependent transcriptional luciferase activity. Downstream targets of STAT3, cyclin D1, Bcl-2, and survivin were also downregulated by LLL12 at both protein and messenger RNA levels. LLL12 is a potent inhibitor of cell viability, with half-maximal inhibitory concentrations values ranging between 0.16 and 3.09 microM, which are lower than the reported JAK2 inhibitor WP1066 and STAT3 inhibitor S3I-201 in six cancer cell lines expressing elevated levels of STAT3 phosphorylation. In addition, LLL12 inhibits colony formation and cell migration and works synergistically with doxorubicin and gemcitabine. Furthermore, LLL12 demonstrated a potent inhibitory activity on breast and glioblastoma tumor growth in a mouse xenograft model. Our results indicate that LLL12 may be a potential therapeutic agent for human cancer cells expressing constitutive STAT3 signaling.

Activity of FB2, a novel dual Abl/Src tyrosine kinase inhibitor, against imatinib-resistant chronic myeloid leukemia in vivo and in vitro.

FB2 is a novel Abl/Src dual tyrosine kinase inhibitor which is designed to overcome imatinib resistance. Besides imatinib-sensitive cell lines (K562), FB2 significantly inhibited the growth of imatinib-resistant cell lines of different resistance mechanisms (K562/G5.0 and K562/G01), and decreased the expression of autophosphorylation of Bcr/Abl, c-Src and Lyn kinases on them. It also inhibited the proliferation of Src over activated cells DU145 and MDA-MB-231. Furthermore, FB2 potently prolonged the survival time of non-obese diabetic/severe combined immunodeficient mice harboured K562/G5.0 cells. These results indicated that FB2, an Abl/Src dual tyrosine kinase inhibitor, is a promising candidate for imatinib-resistant CML and Src over activated cancer.

[Effects of CPUY013, a novel Topo I inhibitor, on human gastric adenocarcinoma BGC823 cells in vitro and in vivo].

Antitumor activity and the mechanism of CPUY013, a novel Topo I inhibitor, on gastric adenocarcinoma BGC823 cells were studied in vitro and in vivo. The proliferation was investigated by MTT assay and colony formation assay. Apoptosis was determined by both dual fluorescence staining with AO and EB and DNA agarose gel electrophoresis analysis methods. Nude mice model of BGC823 xenograft tumor was established by subcutaneous inoculation. The suppression activity of the CPUY013 by intragastric administration on xenograft mice model was detected. The change of cell cycle was studied by flow cytometry assay. The expressions of Topo I, widetype p53, active caspase-3, bcl-2 and bax proteins were analyzed by Western blotting assay. Results showed that CPUY013 could inhibit BGC823 cell proliferation at a certain range of dose. The flow cytometry analysis showed that CPUY013 and topoecan (TPT) led to a decrease in the proportion of G1 phase cells and an increase in the proportion of S phase cells, suggesting that they arrested the transition of tumor cells from S phase to G2 phase. The sub-G1 group was analyzed by flow cytometry. Compared with control, after 48 h treatment with CPUY013 or TPT, the sub-G1 group significantly increased in a dose-dependent manner. CPUY013 and TPT induced apoptosis in tumor cells. Cells treated with CPUY013 for 48 h were stained with AO/EB mixture. Then the cells were observed under fluorescence microscope. And it was found that early and late apoptosis cells were identified by perinuclear condensation of chromatin stained by AO/EB, respectively. Necrotic cells were identified by uniform labeling with EB. With the increase of concentration of CPUY013 and TPT, these morphological changes under the fluorescence microscope become clearer, indicating that the proportion of apoptosis cells increased gradually. By using JC-1 kit, loss of deltapsim was also detected in BGC823 cells treated with CPUY013 and TPT, which represent mitochondria function. And characteristic DNA ladder was observed apparently in BGC823 cells treated with CPUY013. When the xenograft tumor mice were treated with 150 mg x kg(-1) CPUY013, the tumor growth inhibition rate was 62.1%. The expression of bax and p53 proteins increased significantly and bcl-2 and bcl-2/bax decreased after the treatment of the CPUY013. The CPUY013 down-regulated Topo I protein expression and up-regulated active caspase-3 protein expression. The novel Topo I inhibitor CPUY013 can significantly suppress the growth of BGC823 xenograft tumor in vivo and inhibit the proliferation by inducing apoptosis of BGC823 cells in vitro.