βKlotho is identified as a target for theranostics in non-small cell lung cancer

Klotho-beta attenuates Rab8a-mediated exosome regulation and promotes prostate cancer progression

Tumor-secreted exosomes have a wide range of effects on the growth, metastasis, and drug resistance of cancer cells. However, whether and how the molecular mechanisms that regulate the secretion of exosomes could affect tumor progression remains poorly understood. Klotho beta (KLB) has been reported dysregulated in prostate cancer, but its function remains unknown. Herein, we first determined that KLB was upregulated in prostate cancer and its expression level was positively correlated with prostate cancer malignant phenotype both in vitro and in vivo. Intriguingly, KLB overexpression could impair the release of exosomes and cause the intracellular accumulation of multivesicular bodies (MVBs) in prostate cancer cells. Mechanistically, KLB attenuated exosomes secretion through a Rab8a-dependent pathway. Rab8a was downregulated in KLB overexpressing cells whereas overexpression of Rab8a could rescue the impaired release of exosomes and attenuate the KLB-induced malignant phenotype of prostate cancer both in vitro and in vivo. Taken together, this study has unveiled the tumor-promoting role of KLB mediated by its regulation on exosomes secretion through a Rab8a-dependent mechanism. These findings could be exploited to develop novel theranostic targets for prostate cancer.

β-Klotho Promotes the Development of Intrauterine Adhesions via the PI3K/AKT Signaling Pathway

Intrauterine adhesion (IUA) refers to injury to the basal layer of the endometrium, which can be caused by various factors. It is often accompanied by clinical symptoms such as abnormal menstruation, infertility, recurrent abortion, and periodic abdominal pain. In recent years, a number of studies have reported the effects of β-Klotho (KLB) on the occurrence and development of human tumors and fibrotic diseases, but its relationship with endometrial fibroblasts and endometrial fibrosis has not been elucidated. In this study, we compared the expression of KLB in endometrial stromal cells (ESCs) from patients with IUA and normal controls. We constructed animal and cell models of IUA and conducted expression verification and functional experiments on KLB. We found that the expression of KLB was significantly increased in the ESCs of IUA patients and rat models compared with the controls. The overexpression of KLB could promote the proliferation and fibrosis of ESCs. In addition, the overexpression of KLB activated the PI3K/AKT signaling pathway in ESCs. Our study shows that KLB protein is highly expressed in the ESCs of patients with IUA and can enhance stromal cell proliferation and cell fibrosis by activating the PI3K/AKT pathway, thus promoting the development of IUA.

Identification of lung cancer drivers by comparison of the observed and the expected numbers of missense and nonsense mutations in individual human genes

Largely, cancer development is driven by acquisition and positive selection of somatic mutations that increase proliferation and survival of tumor cells. As a result, genes related to cancer development tend to have an excess of somatic mutations in them. An excess of missense and/or nonsense mutations in a gene is an indicator of its cancer relevance. To identify genes with an excess of potentially functional missense or nonsense mutations one needs to compare the observed and expected numbers of mutations in the gene. We estimated the expected numbers of missense and nonsense mutations in individual human genes using (i) the number of potential sites for missense and nonsense mutations in individual transcripts and (ii) histology-specific nucleotide context-dependent mutation rates. To estimate mutation rates defined as the number of mutations per site per tumor we used silent mutations reported in the Catalog Of Somatic Mutations In Cancer (COSMIC). The estimates were nucleotide context dependent. We have identified 26 genes with an excess of missense and/or nonsense mutations for lung adenocarcinoma, 18 genes for small cell lung cancer, and 26 genes for squamous cell carcinoma of the lung. These genes include known genes and novel lung cancer gene candidates.

FGF19 Is Coamplified With CCND1 to Promote Proliferation in Lung Squamous Cell Carcinoma and Their Combined Inhibition Shows Improved Efficacy

Lung squamous cell carcinoma (LUSC) remains as a major cause of cancer-associated mortality with few therapeutic options. Continued research on new driver genes is particularly important. FGF19, a fibroblast growth factor, is frequently observed as amplified in human LUSC, which is also associated with multiple genomic gains and losses. However, the importance of these associated changes is largely unknown. In this study, we aimed to clarify a novel mechanism that link neighboring oncogene co-amplification in the development of LUSC. We found that FGF19 was co-amplified and co-expressed with its neighboring gene CCND1 in a subset of LUSC patients and associated with poor prognosis. Moreover, FGF19 combined with CCND1 promoted the cell cycle progression of LUSC cells. Mechanistically, FGF19 also enhanced CCND1 expression by activating FGFR4-ERK1/2 signaling and strengthening CCND1-induced phosphorylation and inactivation of retinoblastoma (RB). In a murine model of lung orthotopic cancer, knockdown of CCND1 was found to prolong survival by attenuating FGF19-induced cell proliferation. Furthermore, the combination treatment of the FGFR4 inhibitor BLU9931 and the CDK4/6 inhibitor palbociclib potentiated the growth inhibition and arrested cells in G1 phase. In vivo, co-targeting FGFR4 and CDK4/6 also showed marked inhibition of tumor growth than single agent treatment. These findings further elucidate the oncogenic role of FGF19 in LUSC and provide insights into how the co-amplification of neighboring genes synergistically function to promote cancer growth, and combined inhibition against both FGF19 and CCND1 is more effective.

βKlotho Inhibits Cell Proliferation by Downregulating ELK4 and Predicts Favorable Prognosis in Prostate Cancer

Objective

Prostate cancer (PCa) ranks as the second common malignancy in males worldwide. Although conspicuous progressions in diagnosis and treatment have been achieved in the past decades, the prognosis expectation of PCa remains unsatisfied yet. To improve the prognosis prediction of PCa, more specific biomarkers are needed. In this retrospective research, we focused on βKlotho and ETS-like transcription factor 4 (ELK4), aiming to identify potential prognostic biomarkers for PCa.

Methods

Western blotting was used to determine the expression of βKlotho, ELK4, and PARP in C4-2B and PC3 PCa cell lines. CCK-8 assay and colony formation assay were applied to examine the roles of βKlotho and ELK4 in the proliferation of PCa cells. The expression of βKlotho and ELK4 in PCa tissue samples was determined by immunochemistry. Pearson's χ2 test and Fisher's exact test were performed to investigate the associations among βKlotho, ELK4 and various clinical factors. Kaplan-Meier curves and Cox regression model were established to reveal the correlation among βKlotho, ELK4 expression and the prognosis of patients.

Results

βKlotho overexpression down-regulated the ELK4 expression, induced apoptosis and inhibited cell proliferation in both C4-2B and PC3 cells, which were reversed by ELK4 overexpression. βKlotho expression in PCa tissue samples had negative correlation with the ELK4 expression, and higher βKlotho expression was associated with lower Gleason score, absent distant metastasis and lower prostate-specific antigen (PSA) level. On the contrast, higher ELK4 expression was correlated with distant metastasis and higher PSA level. Moreover, βKlotho and ELK4 were both recognized as independent factors for the prognosis of patients with PCa.

Conclusion

βKlotho inhibits proliferation of prostate cancer cells by downregulating ELK4. Both βKlotho and ELK4 expressions correlate with the prognosis of PCa, which may serve as potential biomarkers for follow-up surveillance and prognostic assessments.

The requirement of mitochondrial RNA polymerase for non-small cell lung cancer cell growth

POLRMT (RNA polymerase mitochondrial) is responsible for the transcription of mitochondrial genome encoding key components of oxidative phosphorylation. This process is important for cancer cell growth. The current study tested expression and potential functions of POLRMT in non-small cell lung cancer (NSCLC). TCGA cohorts and the results from the local lung cancer tissues showed that POLRMT is overexpressed in human lung cancer tissues. In both primary human NSCLC cells and A549 cells, POLRMT silencing (by targeted lentiviral shRNAs) or knockout (through CRSIPR/Cas9 gene editing method) potently inhibited cell viability, proliferation, migration, and invasion, and induced apoptosis activation. On the contrast, ectopic overexpression of POLRMT using a lentiviral construct accelerated cell proliferation and migration in NSCLC cells. The mtDNA contents, mRNA levels of mitochondrial transcripts, and subunits of respiratory chain complexes, as well as S6 phosphorylation, were decreased in POLRMT-silenced or -knockout NSCLC cells, but increased after ectopic POLRMT overexpression. In vivo, intratumoral injection of POLRMT shRNA adeno-associated virus (AAV) potently inhibited NSCLC xenograft growth in severe combined immune deficiency mice. The mtDNA contents, mRNA levels of mitochondria respiratory chain complex subunits, and S6 phosphorylation were decreased in POLRMT shRNA AAV-injected NSCLC xenograft tissues. These results show that POLRMT is a novel and important oncogene required for NSCLC cell growth in vitro and in vivo.

βKlotho, a direct target of miR-206, contributes to the growth of hepatoblastoma through augmenting PI3K/Akt/mTOR signaling

Hepatoblastoma (HB) is the most frequent pediatric liver malignancy. However, the treatment outcome for patients with advanced-stage HB remains unsatisfactory. Accumulating evidence indicates that βKlotho (KLB) acts as an oncogene or a tumor-suppressor gene in a context-dependent manner. Despite this, the expression profile and effects of KLB on the growth of HB are still elusive. This study aimed to explore the effect of miR-206/KLB axis on HB growth. The expression of KLB was explored in HB cells (HepG2 and HuH6) and tissues using quantitative polymerase chain reaction (qPCR), Western blot analysis, and immunohistochemistry. Besides, miR-206 expression was determined in HB cells and tissues using qPCR and fluorescence in situ hybridization. The prognostic value of KLB or miR-206 in our patients with HB was investigated using the Kaplan-Meier method. The biological effects of KLB or miR-206 on HB cells were identified in vitro. The proliferative effects of KLB on HuH6 cells were also investigated in vivo. Moreover, the mechanical signaling of KLB in HB was determined through bioinformatics analysis followed by experimental validation. The results showed a significant upregulation of KLB in HB tissues and cells. Elevated level of KLB was found to be significantly correlated with the aggressive phenotype and poor overall survival for children with HB. The in vitro function assay demonstrated that KLB knockdown promoted apoptosis and suppressed the proliferation, migration, and invasion of HB cells. Besides, KLB knockdown inhibited the proliferation of HuH6 cells in vivo, while KLB overexpression had the opposite effect. Furthermore, KLB was proved to be the direct target of miR-206. Low level of miR-206 served as an independent risk factor for poor prognosis in children with HB. The overexpression of miR-206 negatively regulated the aggressive biological behaviors of HB cells, which was partially rescued by KLB overexpression. Mechanically, the miR-206/KLB axis played a vital role in HB growth through augmenting the phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTOR) signaling. In conclusion, the data demonstrated that the miR-206/KLB axis might serve as an important biomarker/therapeutic target for HB.

Serum β-klotho is a potential biomarker in the prediction of clinical outcomes among patients with NSCLC

Background

We aimed to investigate the β-klotho (KLB) expression in non-small cell lung cancer (NSCLC) and to determine its value as a novel molecular target for survival prognosis in patients with NSCLC.

Methods

The serum KLB concentrations in 50 patients with NSCLC and the 20 healthy persons were measured by enzyme-linked immunosorbent assay (ELISA) methods. The relationship between serum KLB level, including the level change after therapy, and the progression-free survival (PFS) and overall survival (OS) were analyzed. The KLB expression in A549 cells was measured by real-time polymerase chain reaction (RT-PCR) and western blotting. The function of cells was revealed by in vitro studies.

Results

The concentrations of serum KLB in patients with NSCLC were obviously lower than those in healthy subjects. KLB expression was significantly increased in patients after chemotherapy and epidermal growth factor receptor tyrosine kinase inhibitor (EGFR-TKI) targeted therapy. In addition, expression of KLB was positively related with PFS and OS. Compared with 16-human bronchial epithelial (HBE) cells, the expression level of KLB was significantly decreased in A549 cells. Overexpression of KLB suppressed the proliferation of A549 cells, along with G1-to-S phase arrest and apoptosis induction.

Conclusions

KLB plays an anti-tumorigenic role in NSCLC. KLB may be a candidate target for the diagnosis and treatment of NSCLC and may serve a potentially significant role in future clinical applications.

Enhanced autocrine FGF19/FGFR4 signaling drives the progression of lung squamous cell carcinoma, which responds to mTOR inhibitor AZD2104

Lung cancer occurrence and associated mortality ranks top in all countries. Despite the rapid development of targeted and immune therapies, many patients experience relapse within a few years. It is urgent to uncover the mechanisms that drive lung cancer progression and identify novel molecular targets. Our group has previously identified FGF19 as a prognostic marker and potential driver gene of lung squamous cell carcinomas (LSQ) in Chinese smoking patients. However, the underlying mechanism of how FGF19 promotes the progression of LSQ remains unclear. In this study, we characterized and confirmed that FGF19 serves as an oncogenic driver in LSQ development and progression, and reported that the amplification and high expression of FGF19 in LSQ was significantly associated with poor overall and progression-free survival. A higher serum level of FGF19 was found in lung cancer patients, which could also serve as a novel diagnostic index to screen lung cancer. Overproduction of FGF19 in LSQ cells markedly promoted cell growth, progression and metastasis, while downregulating FGF19 effectively inhibited LSQ progression in vitro and in vivo. Moreover, downregulating the receptor FGFR4 was also effective to suppress the growth and migration of LSQ cells. Since FGF19 could be induced by smoking or endoplasmic reticulum stress, to tackle the more malignant FGF19-overproducing LSQ, we reported for the first time that inhibiting mTOR pathway by using AZD2014 was effective and feasible. These findings have offered a new strategy by using anti-FGF19/FGFR4 therapy or mTOR-based therapy in FGF19-driven LSQ.