Ciliary neurotrophic factor receptor alpha subunit-modulated multiple downstream signaling pathways in hepatic cancer cell lines and their biological implications

Genetic predisposition to lung adenocarcinoma outcome is a feature already present in patients' noninvolved lung tissue

Emerging evidence suggests that the prognosis of patients with lung adenocarcinoma can be determined from germline variants and transcript levels in nontumoral lung tissue. Gene expression data from noninvolved lung tissue of 483 lung adenocarcinoma patients were tested for correlation with overall survival using multivariable Cox proportional hazard and multivariate machine learning models. For genes whose transcript levels are associated with survival, we used genotype data from 414 patients to identify germline variants acting as cis-expression quantitative trait loci (eQTLs). Associations of eQTL variant genotypes with gene expression and survival were tested. Levels of four transcripts were inversely associated with survival by Cox analysis (CLCF1, hazard ratio [HR] = 1.53; CNTNAP1, HR = 2.17; DUSP14, HR = 1.78; and MT1F: HR = 1.40). Machine learning analysis identified a signature of transcripts associated with lung adenocarcinoma outcome that was largely overlapping with the transcripts identified by Cox analysis, including the three most significant genes (CLCF1, CNTNAP1, and DUSP14). Pathway analysis indicated that the signature is enriched for ECM components. We identified 32 cis-eQTLs for CNTNAP1, including 6 with an inverse correlation and 26 with a direct correlation between the number of minor alleles and transcript levels. Of these, all but one were prognostic: the six with an inverse correlation were associated with better prognosis (HR < 1) while the others were associated with worse prognosis. Our findings provide supportive evidence that genetic predisposition to lung adenocarcinoma outcome is a feature already present in patients' noninvolved lung tissue.

Breast cancer extracellular vesicles-derived miR-1290 activates astrocytes in the brain metastatic microenvironment via the FOXA2→CNTF axis to promote progression of brain metastases

Mechanisms underlying breast cancer brain metastasis (BCBM) are still unclear. In this study, we observed that extracellular vesicles (EVs) secreted from breast cancer cells with increased expression of tGLI1, a BCBM-promoting transcription factor, strongly activated astrocytes. EV-derived microRNA/miRNA microarray revealed tGLI1-positive breast cancer cells highly secreted miR-1290 and miR-1246 encapsulated in EVs. Genetic knockin/knockout studies established a direct link between tGLI1 and both miRNAs. Datamining and analysis of patient samples revealed that BCBM patients had more circulating EV-miRs-1290/1246 than those without metastasis. Ectopic expression of miR-1290 or miR-1246 strongly activated astrocytes whereas their inhibitors abrogated the effect. Conditioned media from miR-1290- or miR-1246-overexpressing astrocytes promoted mammospheres. Furthermore, miRs-1290/1246 suppressed expression of FOXA2 transcription repressor, leading to CNTF cytokine secretion and subsequent activation of astrocytes. Finally, we conducted a mouse study to demonstrate that astrocytes overexpressing miR-1290, but not miR-1246, enhanced intracranial colonization and growth of breast cancer cells. Collectively, our findings demonstrate, for the first time, that breast cancer EV-derived miR-1290 and miR-1246 activate astrocytes in the brain metastatic microenvironment and that EV-derived miR-1290 promotes progression of brain metastases through the novel EV-miR-1290→FOXA2→CNTF signaling axis.

Secondary resistance to anti-EGFR therapy by transcriptional reprogramming in patient-derived colorectal cancer models

BACKGROUND

The development of secondary resistance (SR) in metastatic colorectal cancer (mCRC) treated with anti-epidermal growth factor receptor (anti-EGFR) antibodies is not fully understood at the molecular level. Here we tested in vivo selection of anti-EGFR SR tumors in CRC patient-derived xenograft (PDX) models as a strategy for a molecular dissection of SR mechanisms.

METHODS

We analyzed 21 KRAS, NRAS, BRAF, and PI3K wildtype CRC patient-derived xenograft (PDX) models for their anti-EGFR sensitivity. Furthermore, 31 anti-EGFR SR tumors were generated via chronic in vivo treatment with cetuximab. A multi-omics approach was employed to address molecular primary and secondary resistance mechanisms. Gene set enrichment analyses were used to uncover SR pathways. Targeted therapy of SR PDX models was applied to validate selected SR pathways.

RESULTS

In vivo anti-EGFR SR could be established with high efficiency. Chronic anti-EGFR treatment of CRC PDX tumors induced parallel evolution of multiple resistant lesions with independent molecular SR mechanisms. Mutations in driver genes explained SR development in a subgroup of CRC PDX models, only. Transcriptional reprogramming inducing anti-EGFR SR was discovered as a common mechanism in CRC PDX models frequently leading to RAS signaling pathway activation. We identified cAMP and STAT3 signaling activation, as well as paracrine and autocrine signaling via growth factors as novel anti-EGFR secondary resistance mechanisms. Secondary resistant xenograft tumors could successfully be treated by addressing identified transcriptional changes by tailored targeted therapies.

CONCLUSIONS

Our study demonstrates that SR PDX tumors provide a unique platform to study molecular SR mechanisms and allow testing of multiple treatments for efficient targeting of SR mechanisms, not possible in the patient. Importantly, it suggests that the development of anti-EGFR tolerant cells via transcriptional reprogramming as a cause of anti-EGFR SR in CRC is likely more prevalent than previously anticipated. It emphasizes the need for analyses of SR tumor tissues at a multi-omics level for a comprehensive molecular understanding of anti-EGFR SR in CRC.

The two facets of gp130 signalling in liver tumorigenesis

The liver is a vital organ with multiple functions and a large regenerative capacity. Tumours of the liver are the second most frequently cause of cancer-related death and develop in chronically inflamed livers. IL-6-type cytokines are mediators of inflammation and almost all members signal via the receptor subunit gp130 and the downstream signalling molecule STAT3. We here summarize current knowledge on how gp130 signalling and STAT3 in tumour cells and cells of the tumour micro-environment drives hepatic tumorigenesis. We furthermore discuss very recent findings describing also anti-tumorigenic roles of gp130/STAT3 and important considerations for therapeutic interventions.

Engineering a potent receptor superagonist or antagonist from a novel IL-6 family cytokine ligand

Interleukin-6 (IL-6) family cytokines signal through multimeric receptor complexes, providing unique opportunities to create novel ligand-based therapeutics. The cardiotrophin-like cytokine factor 1 (CLCF1) ligand has been shown to play a role in cancer, osteoporosis, and atherosclerosis. Once bound to ciliary neurotrophic factor receptor (CNTFR), CLCF1 mediates interactions to coreceptors glycoprotein 130 (gp130) and leukemia inhibitory factor receptor (LIFR). By increasing CNTFR-mediated binding to these coreceptors we generated a receptor superagonist which surpassed the potency of natural CNTFR ligands in neuronal signaling. Through additional mutations, we generated a receptor antagonist with increased binding to CNTFR but lack of binding to the coreceptors that inhibited tumor progression in murine xenograft models of nonsmall cell lung cancer. These studies further validate the CLCF1-CNTFR signaling axis as a therapeutic target and highlight an approach of engineering cytokine activity through a small number of mutations.

AMPK activation ameliorates fine particulate matter-induced hepatic injury

Both the epidemiological and animal experimental studies have reported the association between PM_2.5 and respiratory, cardiovascular, and metabolic diseases. However, the study linking PM_2.5 and hepatic injury is few, and the relative mechanism has not been fully elucidated. Thirty-two 6-week-old male C57BL/6 mice were exposed to filtered air (FA) or concentrated PM_2.5 for 12 weeks using Shanghai Meteorological and Environmental Animal Exposure System ("Shanghai-METAS"), respectively. At week 11, the mice began to be treated with intraperitoneal injection of normal 0.9% saline or AMPK activator (AICAR). The mRNA levels of IL-6 and TNF-α, and protein expressions of AMPK, GLUT4, NF-κB, p38MAPK, ERK, and JNK in the liver and UCP-1 in brown adipose tissue (BAT) were measured. Meanwhile, histopathological examination both in the liver and BAT was performed to evaluate the histopathological changes. PM_2.5 exposure induced steatosis, hepatocyte ballooning, lobular and portal inflammation in the liver, and the brown adipocyte swelling in BAT. The results found that PM mice displayed higher IL-6, TNF-α, NF-κB, and JNK expression and lower AMPK, GLUT4, and UCP-1 when compared with FA mice. The AICAR injection upregulated the expressions of GLUT4 in the liver of PM-AIC mice when compared with the PM mice. However, there were no significant effects of AICAR on histopathological condition. The current study showed that ambient PM_2.5 exposure might induce the hepatic injury along with the lipid metabolism disorder in BAT. AMPK activation can ameliorate most of the harmful effects and might become the potential target for treating PM_2.5-induced hepatic injury.

Time-series clustering of cytokine expression after transarterial chemoembolization in patients with hepatocellular carcinoma

Cytokines play an important role in the development of tumors. The purpose of the present study was to evaluate the mechanisms and cytokine level changes after transarterial chemoembolization (TACE) in patients with hepatocellular carcinoma (HCC). The Short Time-series Expression Miner (STEM) program was utilized to cluster cytokine expression profiles from the day before TACE to day 21 post-TACE. Based on the identified significant signatures, Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes pathway analyses were performed. Cytokines were serially monitored in 60 evaluable patients to identify the results of the STEM program. Examination of the significant signatures identified 6 significant time-varied expression patterns for 507 cytokines (profiles 16, 18, 28, 41, 42 and 43). GO analysis was enriched in 'cytokine receptor-binding' and 'cytokine receptor activity', and the identified signaling pathways included 'cytokine-cytokine receptor interaction' and the 'JAK-STAT signaling pathway'. Ciliary neurotrophic factor (CNTF) level was increased early after TACE, reaching a peak on day 7 before finally decreasing from day 14 onwards, and was significantly positively correlated with aminotransferase level. Serum levels of pre-TACE IL-10 predicted the local tumor response and overall survival (OS) of the patients, while serum levels of post-TACE IL-1β only indicated the local tumor response of the patient. Overall, the present study identified cytokine time-series expression profiles of patients with HCC undergoing TACE. Early phase increases in CNTF after TACE were associated with post-treatment hepatic injury. IL-1β may reflect an objective response after TACE, while IL-10 may represent a biomarker for OS and the objective response pre-TACE, which may help patients with HCC to benefit from TACE.

Antitumor activity of an engineered decoy receptor targeting CLCF1-CNTFR signaling in lung adenocarcinoma

Proinflammatory cytokines in the tumor microenvironment can promote tumor growth, yet their value as therapeutic targets remains underexploited. We validated the functional significance of the cardiotrophin-like cytokine factor 1 (CLCF1)-ciliary neurotrophic factor receptor (CNTFR) signaling axis in lung adenocarcinoma (LUAD) and generated a high-affinity soluble receptor (eCNTFR-Fc) that sequesters CLCF1, thereby inhibiting its oncogenic effects. eCNTFR-Fc inhibits tumor growth in multiple xenograft models and in an autochthonous, highly aggressive genetically engineered mouse model of LUAD, driven by activation of oncogenic Kras and loss of Trp53. Abrogation of CLCF1 through eCNTFR-Fc appears most effective in tumors driven by oncogenic KRAS. We observed a correlation between the effectiveness of eCNTFR-Fc and the presence of KRAS mutations that retain the intrinsic capacity to hydrolyze guanosine triphosphate, suggesting that the mechanism of action may be related to altered guanosine triphosphate loading. Overall, we nominate blockade of CLCF1-CNTFR signaling as a novel therapeutic opportunity for LUAD and potentially for other tumor types in which CLCF1 is present in the tumor microenvironment.

Pretumor microenvironment of hepatocellular carcinoma: Cancerization or anticancerization?

BACKGROUND

Tumor microenvironment (TM) has been deeply concerned. However, the pretumor microenvironment (PTM) was poorly understood. The purpose in this study was to explore the possible pathophysiological features of PTM before hepatocellular carcinoma (HCC) appearance.

METHODS

Mouse livers with no swelling but with tumors present elsewhere in the body after subcutaneous injection of H22 in the fore underarm were considered a PTM, HCC tumors presenting far away from the PTM were regarded as a TM, and the healthy livers of mice without injection of H22 were regarded as a physiological microenvironment (PM). The transcriptomes of samples were generated using RNA-seq and validated using RT-qPCR.

RESULTS

Overall, 4483 differentially expressed genes (DEGs) were found in the TM compared with the PTM (TM/PTM), but only 194 were altered in the PTM compared with the PM (PTM/PM). Among those 194 DEGs, 104 displayed upregulation and 90 downregulation. Some of these DEGs could promote the ability to resist cancerization or facilitate cancer metastasis, while others indicated liver impairment. The DEGs were involved in 16 relevant pathways. Additionally, the frequency of alternative splicing (AS) in the DEGs in various samples was positively related to the expression of those DEGs.

CONCLUSIONS

The PTM initiatively armed itself to combat cancerization when its indications appeared although the PTM did not manifest any tissue swelling. However, the cancer cells were negatively influencing immunity to prevent clearance and positively promoting transformation to construct a suitable environment. During transformation by cancer cells, some genes with acquired AS participated in the construction of the PTM. This alteration created an invadable space and an appropriate environment for cancer cells.

Hypomethylation of CNTFRα is associated with proliferation and poor prognosis in lower grade gliomas

Ciliary neurotrophic factor receptor α subunit (CNTFRα) and CNTF play important roles in neuron survival, glial differentiation and brain tumor growth. However, the molecular mechanisms of CNTFRα regulation and its clinical significance in glioma remain largely unknown. Here, we found CNTFRα was overexpressed in lower grade gliomas (LGG) compared with glioblastoma (GBM) and normal brain specimens in TCGA datasets and in an independent cohort. Bioinformatics analysis revealed a CpG shore of the CNTFRα gene regulated its mRNA expression in TCGA datasets. This observation was further validated with clinical specimens and functionally verified using demethylating agents. Additionally, we observed that independent of IDH mutation status, methylation of CNTFRα was significantly correlated with down-regulated CNTFRα gene expression and longer LGG patient survival. Interestingly, combination of CNTFRα methylation and IDH mutation significantly (p < 0.05) improved the prognostic prediction in LGG patients. Furthermore, the role of CNTFRα in glioma proliferation and apoptosis through the PI3K/AKT pathways was demonstrated by supplementation with exogenous CNTF  in vitro and siRNA knockdown in vivo. Our study demonstrated that hypomethylation leading to CNTFRα up-regulation, together with autocrine expression of CNTF, was involved in glioma growth regulation. Importantly, DNA methylation of CNTFRα might serve as a potential epigenetic theranostic target for LGG patients.

MiR-696 Regulates C2C12 Cell Proliferation and Differentiation by Targeting CNTFRα

Micro-696 (miR-696) has been previously known as an exercise related miRNA, which has a profound role in fatty acid oxidation and mitochondrial biogenesis of skeletal muscle. However, its role in skeletal myoblast proliferation and differentiation is still unclear. In this study, we found that miR-696 expressed highly in skeletal muscle and reduced during C2C12 myoblasts differentiation. MiR-696 overexpression repressed C2C12 myoblast proliferation and myofiber formation, while knockdown of endogenous miR-696 expression showed opposite results. During myogenesis, we observed an inversed expression pattern between miR-696 and CNTFRα in vitro, and demonstrated that miR-696 could specifically target CNTFRα and repress the expression of CNTFRα. Additionally, we further found that knockdown of CNTFRα suppressed the proliferation and differentiation of C2C12 cells. Taking all things together, we propose a novel insight that miR-696 down-regulates C2C12 cell myogenesis by inhibiting CNTFRα expression.

Reprogramming of glucose metabolism in hepatocellular carcinoma: Progress and prospects

Hepatocellular carcinoma (HCC) is one of the most lethal cancers, and its rate of incidence is rising annually. Despite the progress in diagnosis and treatment, the overall prognoses of HCC patients remain dismal due to the difficulties in early diagnosis and the high level of tumor invasion, metastasis and recurrence. It is urgent to explore the underlying mechanism of HCC carcinogenesis and progression to find out the specific biomarkers for HCC early diagnosis and the promising target for HCC chemotherapy. Recently, the reprogramming of cancer metabolism has been identified as a hallmark of cancer. The shift from the oxidative phosphorylation metabolic pathway to the glycolysis pathway in HCC meets the demands of rapid cell proliferation and offers a favorable microenvironment for tumor progression. Such metabolic reprogramming could be considered as a critical link between the different HCC genotypes and phenotypes. The regulation of metabolic reprogramming in cancer is complex and may occur via genetic mutations and epigenetic modulations including oncogenes, tumor suppressor genes, signaling pathways, noncoding RNAs, and glycolytic enzymes etc. Understanding the regulatory mechanisms of glycolysis in HCC may enrich our knowledge of hepatocellular carcinogenesis and provide important foundations in the search for novel diagnostic biomarkers and promising therapeutic targets for HCC.

RNA-Seq reveals 10 novel promising candidate genes affecting milk protein concentration in the Chinese Holstein population

Paired-end RNA sequencing (RNA-Seq) was used to explore the bovine transcriptome from the mammary tissue of 12 Chinese Holstein cows with 6 extremely high and 6 low phenotypic values for milk protein percentage. We defined the differentially expressed transcripts between the two comparison groups, extremely high and low milk protein percentage during the peak lactation (HP vs LP) and during the non-lactating period (HD vs LD), respectively. Within the differentially expressed genes (DEGs), we detected 157 at peak lactation and 497 in the non-lactating period with a highly significant correlation with milk protein concentration. Integrated interpretation of differential gene expression indicated that SERPINA1, CLU, CNTFR, ERBB2, NEDD4L, ANG, GALE, HSPA8, LPAR6 and CD14 are the most promising candidate genes affecting milk protein concentration. Similarly, LTF, FCGR3A, MEGF10, RRM2 and UBE2C are the most promising candidates that in the non-lactating period could help the mammary tissue prevent issues with inflammation and udder disorders. Putative genes will be valuable resources for designing better breeding strategies to optimize the content of milk protein and also to provide new insights into regulation of lactogenesis.

Ciliary neurotrophic factor (CNTF) protects non-obese Swiss mice against type 2 diabetes by increasing beta cell mass and reducing insulin clearance

AIMS/HYPOTHESIS

Ciliary neurotrophic factor (CNTF) improves metabolic variables of obese animals with characteristics of type 2 diabetes, mainly by reducing insulin resistance. We evaluated whether CNTF was able to improve other metabolic variables in mouse models of type 2 diabetes, such as beta cell mass and insulin clearance, and whether CNTF has any effect on non-obese mice with characteristics of type 2 diabetes.

METHODS

Neonatal mice were treated with 0.1 mg/kg CNTF or citrate buffer via intraperitoneal injections, before injection of 250 mg/kg alloxan. HEPG2 cells were cultured for 3 days in the presence of citrate buffer, 1 nmol/l CNTF or 50 mmol/l alloxan or a combination of CNTF and alloxan. Twenty-one days after treatment, we determined body weight, epididymal fat weight, blood glucose, plasma insulin, NEFA, glucose tolerance, insulin resistance, insulin clearance and beta cell mass. Finally, we assessed insulin receptor and protein kinase B phosphorylation in peripheral organs, as well as insulin-degrading enzyme (IDE) protein production and alternative splicing in the liver and HEPG2 cells.

RESULTS

CNTF improved insulin sensitivity and beta cell mass, while reducing glucose-stimulated insulin secretion and insulin clearance in Swiss mice, improving glucose handling in a non-obese type 2 diabetes model. This effect was associated with lower IDE production and activity in liver cells. All these effects were observed even at 21 days after CNTF treatment.

CONCLUSIONS/INTERPRETATION

CNTF protection against type 2 diabetes is partially independent of the anti-obesity actions of CNTF, requiring a reduction in insulin clearance and increased beta cell mass, besides increased insulin sensitivity. Furthermore, knowledge of the long-term effects of CNTF expands its pharmacological relevance.

Acetylcholinesterase, a key prognostic predictor for hepatocellular carcinoma, suppresses cell growth and induces chemosensitization

Acetylcholinesterase (ACHE) plays important roles in the cholinergic system, and its dysregulation is involved in a variety of human diseases. However, the roles and implications of ACHE in hepatocellular carcinoma (HCC) remain elusive. Here we demonstrate that ACHE was significantly down-regulated in the cancerous tissues of 69.2% of HCC patients, and the low ACHE expression in HCC was correlated with tumor aggressiveness, an elevated risk of postoperative recurrence, and a low survival rate. Both the recombinant ACHE protein and the enhanced expression of ACHE significantly inhibited HCC cell growth in vitro and tumorigenicity in vivo. Further study showed that ACHE suppressed cell proliferation via its enzymatic activity of acetylcholine catalysis and degradation. Moreover, ACHE could inactivate mitogen-activated protein kinase and phosphatidyl inositol-3'-phosphate kinase/protein kinase B pathways in HCC cells and thereby increase the activation of glycogen synthase kinase 3β and lead to β-catenin degradation and cyclin D1 suppression. In addition, increased ACHE expression could remarkably sensitize HCC cells to chemotherapeutic drugs (i.e., adriamycin and etoposide).

CONCLUSION

For the first time, we describe the function of ACHE as a tumor growth suppressor in regulating cell proliferation, the relevant signaling pathways, and the drug sensitivity of HCC cells. ACHE is a promising independent prognostic predictor for HCC recurrence and the survival of HCC patients. These findings provide new insights into potential strategies for drug discovery and improved HCC treatment.

AMPK in Health and Disease

The function and survival of all organisms is dependent on the dynamic control of energy metabolism, when energy demand is matched to energy supply. The AMP-activated protein kinase (AMPK) alphabetagamma heterotrimer has emerged as an important integrator of signals that control energy balance through the regulation of multiple biochemical pathways in all eukaryotes. In this review, we begin with the discovery of the AMPK family and discuss the recent structural studies that have revealed the molecular basis for AMP binding to the enzyme's gamma subunit. AMPK's regulation involves autoinhibitory features and phosphorylation of both the catalytic alpha subunit and the beta-targeting subunit. We review the role of AMPK at the cellular level through examination of its many substrates and discuss how it controls cellular energy balance. We look at how AMPK integrates stress responses such as exercise as well as nutrient and hormonal signals to control food intake, energy expenditure, and substrate utilization at the whole body level. Lastly, we review the possible role of AMPK in multiple common diseases and the role of the new age of drugs targeting AMPK signaling.

AMPK-dependent hormonal regulation of whole-body energy metabolism

AMP-dependent protein kinase (AMPK) is an evolutionarily conserved serine/threonine protein kinase central to the regulation of energy balance at both the cellular and whole-body levels. In its classical role as an intracellular metabolic stress-sensing kinase, AMPK switches on fatty acid oxidation and glucose uptake in muscle, while switching off hepatic gluconeogenesis. AMPK also has a broader role in metabolism through the control of appetite. Regulation of AMPK activity at the whole-body level is coordinated by a growing number of hormones and cytokines secreted from adipose tissue, skeletal muscle, pancreas and the gut including leptin, adiponectin, insulin, interluekin-6, resistin, TNF-alpha and ghrelin. Understanding how these secreted signalling proteins regulate AMPK activity to control fatty acid oxidation, glucose uptake, gluconeogenesis and appetite may yield therapeutic treatments for metabolic disorders such as diabetes, insulin resistance and obesity.