Pangenome analysis reveals transposon-driven genome evolution in cotton.

BACKGROUND: Transposable elements (TEs) have a profound influence on the trajectory of plant evolution, driving genome expansion and catalyzing phenotypic diversification. The pangenome, a comprehensive genetic pool encompassing all variations within a species, serves as an invaluable tool, unaffected by the confounding factors of intraspecific diversity. This allows for a more nuanced exploration of plant TE evolution. RESULTS: Here, we constructed a pangenome for diploid A-genome cotton using 344 accessions from representative geographical regions, including 223 from China as the main component. We found 511 Mb of non-reference sequences (NRSs) and revealed the presence of 5479 previously undiscovered protein-coding genes. Our comprehensive approach enabled us to decipher the genetic underpinnings of the distinct geographic distributions of cotton. Notably, we identified 3301 presence-absence variations (PAVs) that are closely tied to gene expression patterns within the pangenome, among which 2342 novel expression quantitative trait loci (eQTLs) were found residing in NRSs. Our investigation also unveiled contrasting patterns of transposon proliferation between diploid and tetraploid cotton, with long terminal repeat (LTR) retrotransposons exhibiting a synchronized surge in polyploids. Furthermore, the invasion of LTR retrotransposons from the A subgenome to the D subgenome triggered a substantial expansion of the latter following polyploidization. In addition, we found that TE insertions were responsible for the loss of 36.2% of species-specific genes, as well as the generation of entirely new species-specific genes. CONCLUSIONS: Our pangenome analyses provide new insights into cotton genomics and subgenome dynamics after polyploidization and demonstrate the power of pangenome approaches for elucidating transposon impacts and genome evolution.

High-quality Gossypium hirsutum and Gossypium barbadense genome assemblies reveal the landscape and evolution of centromeres.

Centromere positioning and organization are crucial for genome evolution; however, research on centromere biology is largely influenced by the quality of available genome assemblies. Here, we combined Oxford Nanopore and Pacific Biosciences technologies to de novo assemble two high-quality reference genomes for Gossypium hirsutum (TM-1) and Gossypium barbadense (3-79). Compared with previously published reference genomes, our assemblies show substantial improvements, with the contig N50 improved by 4.6-fold and 5.6-fold, respectively, and thus represent the most complete cotton genomes to date. These high-quality reference genomes enable us to characterize 14 and 5 complete centromeric regions for G. hirsutum and G. barbadense, respectively. Our data revealed that the centromeres of allotetraploid cotton are occupied by members of the centromeric repeat for maize (CRM) and Tekay long terminal repeat families, and the CRM family reshapes the centromere structure of the At subgenome after polyploidization. These two intertwined families have driven the convergent evolution of centromeres between the two subgenomes, ensuring centromere function and genome stability. In addition, the repositioning and high sequence divergence of centromeres between G. hirsutum and G. barbadense have contributed to speciation and centromere diversity. This study sheds light on centromere evolution in a significant crop and provides an alternative approach for exploring the evolution of polyploid plants.

Regulatory controls of duplicated gene expression during fiber development in allotetraploid cotton.

Polyploidy complicates transcriptional regulation and increases phenotypic diversity in organisms. The dynamics of genetic regulation of gene expression between coresident subgenomes in polyploids remains to be understood. Here we document the genetic regulation of fiber development in allotetraploid cotton Gossypium hirsutum by sequencing 376 genomes and 2,215 time-series transcriptomes. We characterize 1,258 genes comprising 36 genetic modules that control staged fiber development and uncover genetic components governing their partitioned expression relative to subgenomic duplicated genes (homoeologs). Only about 30% of fiber quality-related homoeologs show phenotypically favorable allele aggregation in cultivars, highlighting the potential for subgenome additivity in fiber improvement. We envision a genome-enabled breeding strategy, with particular attention to 48 favorable alleles related to fiber phenotypes that have been subjected to purifying selection during domestication. Our work delineates the dynamics of gene regulation during fiber development and highlights the potential of subgenomic coordination underpinning phenotypes in polyploid plants.

[Corrigendum] RON and c­Met facilitate metastasis through the ERK signaling pathway in prostate cancer cells.

Subsequently to the publication of the above article, the authors have discovered that the version of Fig. 5 included in the paper was an incorrect version, and that two pairs of data panels were inadvertently included in Fig. 6D (the data panels for the NC+migration and NC+HGF+U0126+invasion experiments for the PC3 cells, and the data panels for the NC+invasion and NC+HGF+U0126+invasion experiments for the DU145 cells) that contained overlapping data derived from the same source. These data were intended to represent the results obtained under different experimental conditions. Furthermore, the GAPDH control bands in Fig. 4A (DU145 cells) and the p­ERK1/2 bands in Fig. 6A (PC3 cells) were incorrectly chosen for these figures. After having consulted the original data, the authors discovered that unintended errors were made in assembling the data for these graphs. In uploading the corrected version of Fig. 5, Fig. 3C and D and Fig. 4C and D were adjusted accordingly. The corrected versions of Figs. 3, 4, 5, and 6 are shown on the subsequent pages. The authors regret the errors that were made during the preparation of the published figures, and confirm that these errors did not affect the conclusions reported in the study. The authors are grateful to the Editor of Oncology Reports for allowing them the opportunity to publish a Corrigendum, and all the authors agree to this Corrigendum. Furthermore, they apologize to the readership for any inconvenience caused. [Oncology Reports 37: 3209­3218, 2017; DOI: 10.3892/or.2017.5585].

Dynamic 3D genome architecture of cotton fiber reveals subgenome-coordinated chromatin topology for 4-staged single-cell differentiation.

BACKGROUND: Despite remarkable advances in our knowledge of epigenetically mediated transcriptional programming of cell differentiation in plants, little is known about chromatin topology and its functional implications in this process. RESULTS: To interrogate its significance, we establish the dynamic three-dimensional (3D) genome architecture of the allotetraploid cotton fiber, representing a typical single cell undergoing staged development in plants. We show that the subgenome-relayed switching of the chromatin compartment from active to inactive is coupled with the silencing of developmentally repressed genes, pinpointing subgenome-coordinated contribution to fiber development. We identify 10,571 topologically associating domain-like (TAD-like) structures, of which 25.6% are specifically organized in different stages and 75.23% are subject to partition or fusion between two subgenomes. Notably, dissolution of intricate TAD-like structure cliques showing long-range interactions represents a prominent characteristic at the later developmental stage. Dynamic chromatin loops are found to mediate the rewiring of gene regulatory networks that exhibit a significant difference between the two subgenomes, implicating expression bias of homologous genes. CONCLUSIONS: This study sheds light on the spatial-temporal asymmetric chromatin structures of two subgenomes in the cotton fiber and offers a new insight into the regulatory orchestration of cell differentiation in plants.

A Multivariate Diagnostic Model Based on Urinary EpCAM-CD9-Positive Extracellular Vesicles for Prostate Cancer Diagnosis.

INTRODUCTION: Prostate cancer (PCa) is one of the most frequently diagnosed cancers and the leading cause of cancer death in males worldwide. Although prostate-specific antigen (PSA) screening has considerably improved the detection of PCa, it has also led to a dramatic increase in overdiagnosing indolent disease due to its low specificity. This study aimed to develop and validate a multivariate diagnostic model based on the urinary epithelial cell adhesion molecule (EpCAM)-CD9-positive extracellular vesicles (EVs) (uEVEpCAM-CD9) to improve the diagnosis of PCa. METHODS: We investigated the performance of uEVEpCAM-CD9 from urine samples of 193 participants (112 PCa patients, 55 benign prostatic hyperplasia patients, and 26 healthy donors) to diagnose PCa using our laboratory-developed chemiluminescent immunoassay. We applied machine learning to training sets and subsequently evaluated the multivariate diagnostic model based on uEVEpCAM-CD9 in validation sets. RESULTS: Results showed that uEVEpCAM-CD9 was able to distinguish PCa from controls, and a significant decrease of uEVEpCAM-CD9 was observed after prostatectomy. We further used a training set (N = 116) and constructed an exclusive multivariate diagnostic model based on uEVEpCAM-CD9, PSA, and other clinical parameters, which showed an enhanced diagnostic sensitivity and specificity and performed excellently to diagnose PCa [area under the curve (AUC) = 0.952, P < 0.0001]. When applied to a validation test (N = 77), the model achieved an AUC of 0.947 (P < 0.0001). Moreover, this diagnostic model also exhibited a superior diagnostic performance (AUC = 0.917, P < 0.0001) over PSA (AUC = 0.712, P = 0.0018) at the PSA gray zone. CONCLUSIONS: The multivariate model based on uEVEpCAM-CD9 achieved a notable diagnostic performance to diagnose PCa. In the future, this model may potentially be used to better select patients for prostate transrectal ultrasound (TRUS) biopsy.

Prostatic aspirated cellular RNA analysis enables fast diagnosis and staging of prostate cancer.

OBJECTIVE: The aim of this study is to investigate the potential application of prostatic aspirated cellular RNA analysis technique for fast diagnosing and staging prostate cancer. METHODS: Prostatic aspirated cells were obtained immediately after transrectal ultrasound (TRUS)-guided needle biopsy. Cellular RNA such as glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA, prostate specific antigen (PSA) mRNA and prostate-specific RNA (PCA3) mRNA were analyzed by using Reverse Transcription-Polymerase Chain Reaction (RT-PCR). PCA3 score was calculated as the ratio of PCA3 mRNA to PSA mRNA expression. Diagnostic performance of the fast-aspirated cellular RNA analysis technique for determining prostate cancer and metastatic status were evaluated by developing receiver operating characteristic curves (ROC), and the correlation between aspirated cellular RNA mRNA expressions and risk grouping was calculated, to investigate the underlying potential for PCa staging. RESULTS: PCA3 score was significantly higher in prostatic aspirated cells obtained from cancerous tissues than noncancerous tissues. The median aspirated cellular PCA3 score was higher in patients with PCa compared to BPH, and presenting an area under the ROC curve (AUC) of 0.87 (95%CI: 0.79-0.94) for PCa diagnosis. Multivariate regression analysis revealed that baseline median aspirated cellular PCA3 score (OR=9.316, 95%CI: 1.045-83.033, P<0.05) was an independent predictive factor for metastatic status in PCa patients. CONCLUSION: The ease of use and minimal complexity of fast prostatic aspirated cellular RNA analysis may be a valuable diagnostic technique, providing urgent diagnostic information for accurate PCa diagnosing and staging.

New application of Mn-doped ZnS quantum dots: phosphorescent sensor for the rapid screening of chloramphenicol and tetracycline residues.

In this work, a new application of Mn-doped ZnS quantum dots (Mn-ZnS QDs) was developed to screen chloramphenicol (CAP) and tetracycline (TC) residues simply and rapidly. Mn-ZnS QDs synthesized by a hydration method and modified by l-cysteine for better stability emit phosphorescence at 583 nm with the excitation wavelength at 289 nm. Based on the overlap of the Mn-ZnS QDs excitation spectra and CAP or TCs ultraviolet spectra, the excited light of the Mn-ZnS QDs was partially absorbed by CAP or TCs owing to the inner-filter effect (IFE), leading to a decrease in the phosphorescence intensity. The phosphorescence intensities of the samples prepared by mixing different TCs and CAP were in good agreement with the expected results from adding a single antibiotic sample. Therefore, the total molar concentrations of CAP and TCs could be screened based on the linear equation of a single standard substance. Represented by tetracycline (TC), as a member of the tetracycline family, under optimized conditions, showed a good linear relational concentration range over 4 orders of magnitude from 50 to 1.5 × 105 nM with a limit of detection (LOD; S/N ratio = 3) down to 8.6 nM. The phosphorescent sensor was also used to detect total TCs in actual samples successfully. The evaluations of the recovery rate and selectivity were good. These results demonstrated that the presented phosphorescent sensor can be a simple and rapid screening platform for CAP and TCs.

Kin17 knockdown suppresses the migration and invasion of cervical cancer cells through NF-κB-Snail pathway.

Cervical cancer is one of the most common cancers in women worldwide. Metastasis in cancer has been a Gordian knot due to unsatisfactory clinical treatments. KIN17, a highly conserved gene from yeast to human, up-regulation is associated with the pathogenesis and development of several common cancers. Our previous works revealed that elevated expression of kin17 observed in cervical cancer tissues showed a close association with lymph node metastasis. This study aimed to explore roles and mechanisms of kin17 in the migration and invasion of cervical cancer cells. Cervical cancer cell lines HeLa and SiHa with kin17 knockdown were constructed by using recombinant lentiviral vector that carry specific siRNA targeting KIN17 gene. The mRNA and protein levels of kin17 in cells were determined by RT-qPCR and western blotting, respectively. Wound healing assay and transwell assays were performed to assess the migration and invasion abilities of the cancer cells, respectively. The expression of signaling proteins involved in the NF-κB-Snail pathway was analyzed by western blotting. As our results showed, the mRNA and protein levels of kin17 in HeLa cells and SiHa cells showed a significant decrease by transfection with recombinant lentiviral vector carrying specific siRNA. Compared with control group, the migration rates were decreased in the kin17 knockdown group in both HeLa and SiHa cell lines in wound healing assay as well as transwell assay without matrigel. Kin17 knockdown also reduced the cell invasion number of both HeLa and SiHa cells. In addition, the phosphorylation of nuclear factor Kαppa B (NF-κB) p65, IKαppa B kinase α (IKKα), and IKαppa B α (IκBα) in NF-κB pathway and the expression of Snail were decreased in HeLa cells and SiHa cells by kin17 knockdown. Our results demonstrated that knockdown of kin17 in cervical cancer cells suppressed cell migration and invasion, and inhibited the activity of NF-κB signaling pathway and the expression of Snail. These findings suggested kin17 as an essential regulator of the cell migration and invasion and the underlying molecular mechanism involved NF-κB-Snail pathway in cervical cancer. This might serve as a novel molecular therapeutic target for treating cervical cancer metastasis.

Integrated profiling identifies SLC5A6 and MFAP2 as novel diagnostic and prognostic biomarkers in gastric cancer patients.

Gastric cancer (GC) is one of the leading causes of malignancy­associated mortality worldwide. However, the underlying molecular mechanisms of GC are unclear and the prognosis of GC is poor. Therefore, it is important and urgent to explore the underlying mechanisms and screen for novel diagnostic and prognostic biomarkers, as well as therapeutic targets. In the current study, scale­free gene co­expression networks were constructed using weighted gene co­expression network analysis, the potential associations between gene sets and clinical features were investigated, and the hub genes were identified. The gene expression profiles of GSE38749 were downloaded from the Gene Expression Omnibus database. RNA­seq and clinical data for GC from The Cancer Genome Atlas were utilized for verification. Furthermore, the expression of candidate biomarkers in gastric tissues was investigated. Survival analysis was performed using Kaplan­Meier and log­rank test. The predictive role of candidate biomarkers in GC was evaluated using a receiver operator characteristic (ROC) curve. Gene Ontology, gene set enrichment analysis and gene set variation analysis methods were used to interpret the function of candidate biomarkers in GC. A total of 29 modules were identified via the average linkage hierarchical clustering. A significant module consisting of 48 genes associated with clinical traits was found; three genes with high connectivity in the clinical significant module were identified as hub genes. Among them, SLC5A6 and microfibril­associated protein 2 (MFAP2) were negatively associated with the overall survival, and their expression was elevated in GC compared with non­tumor tissues. Additionally, ROC curves indicated that SLC5A6 and MFAP2 showed a good diagnostic power in discriminating cancerous from normal tissues. SLC5A6 and MFAP2 were identified as novel diagnostic and prognostic biomarkers in GC patients; both of these genes were first reported here in connection with GC and deserved further research.

Rapid and Quantitative Analysis of Exosomes by a Chemiluminescence Immunoassay Using Superparamagnetic Iron Oxide Particles.

Since the discovery of exosomes, their potential diagnostic value has been the focus of considerable research. However, the lack of a rapid and simple technique for the quantitative analysis of exosomes greatly limits the application of exosomes in clinical research. In this study, we describe a newly developed one-step chemiluminescence immunoassay for the rapid quantitative analysis of exosomes from biofluids. Our new technique, named ExoNANO, adopts a double-antibody sandwich strategy using anti-CD63 antibody-conjugated superparamagnetic iron oxide particles (SIOPs) and acridinium ester (ACE)-labeled anti-CD9 antibodies. SIOPs have narrow size distribution and high magnetic susceptibility, and ACE has excellent chemiluminescent properties such as low background signal and no need for a catalyst. We demonstrated that ExoNANO allows the quantitative analysis of exosomes in the range of 2.92 ×105 to 2.80×108 particles/µL, with a limit of detection of 2.63×105 particles/µL. Using ExoNANO, we quantified exosomes in cell culture medium and clinical biofluids such as serum, saliva, ascitic fluid, and cerebrospinal fluid. We believe that ExoNANO might pave the way for the rapid isolation and quantitative analysis of exosomes for routine clinical applications.

High expression of HMBOX1 contributes to poor prognosis of gastric cancer by promoting cell proliferation and migration.

Homeobox-containing 1 (HMBOX1) has been reported to be associated with biological characteristics of some tumors, but its roles in gastric cancer have never been reported. In the present study, we found that HMBOX1 expression was significantly upregulated in gastric cancer tissues and cell lines and correlated with the TNM stage, lymph-node metastatic and the overall survival (OS) of patients of gastric cancer. The overexpression of HMBOX1 in gastric cancer cells enhanced cell proliferation by accelerating cell cycle, induced cell migration. In contrast, silencing HMBOX1 inhibited these processes. And the expression of HMBOX1 was related with the expression of vascular endothelial growth factor receptor (VEGFR), transforming growth factor-ß (TGF-ß) and CD133. What's more, we found that the expression of CD133 had a significantly positive correlation with HMBOX1 in gastric cancer tissues, and the co-expression of HMBOX1 and CD133 was significantly correlated with poor prognosis of gastric cancer patients, especially for patients at III and IV stage. In conclusion, HMBOX1 was upregulated in gastric cancer and correlated with gastric cancer cell proliferation and migration. Moreover, HMBOX1 combined CD133 might be useful to predict survival of patients with advanced gastric cancer.

Knockdown of DNA/RNA-binding protein KIN17 promotes apoptosis of triple-negative breast cancer cells.

Effective therapy for breast cancer has been extensively studied worldwide, particularly for triple-negative breast cancer and drug-resistant subtypes. DNA/RNA-binding protein KIN17 (kin17) has been reported to be significantly upregulated in breast cancer cells, and is proposed to serve a role in the regulation of cell proliferation. The present study further investigated the association of kin17-knockdown with breast cancer cell apoptosis. Cell Counting kit-8, flow cytometry, TUNEL assay and caspase 3/7 analysis were performed on MDA-MB-231 cells to determine the association between kin17 and breast cancer cell apoptosis. In addition, western blot analysis was performed to investigate the mechanism of kin17 in the apoptosis of MDA-MB-231 cells. The results revealed that knockdown of kin17 inhibited proliferation and promoted apoptosis of MDA-MB-231 cells, and suggested a poly (adenosine diphosphate-ribose) polymerase-related mechanism behind the apoptosis of the cells. These findings suggested that kin17 could become a novel target for breast cancer therapy.

Reference genome sequences of two cultivated allotetraploid cottons, Gossypium hirsutum and Gossypium barbadense.

Allotetraploid cotton species (Gossypium hirsutum and Gossypium barbadense) have long been cultivated worldwide for natural renewable textile fibers. The draft genome sequences of both species are available but they are highly fragmented and incomplete1-4. Here we report reference-grade genome assemblies and annotations for G. hirsutum accession Texas Marker-1 (TM-1) and G. barbadense accession 3-79 by integrating single-molecule real-time sequencing, BioNano optical mapping and high-throughput chromosome conformation capture techniques. Compared with previous assembled draft genomes1,3, these genome sequences show considerable improvements in contiguity and completeness for regions with high content of repeats such as centromeres. Comparative genomics analyses identify extensive structural variations that probably occurred after polyploidization, highlighted by large paracentric/pericentric inversions in 14 chromosomes. We constructed an introgression line population to introduce favorable chromosome segments from G. barbadense to G. hirsutum, allowing us to identify 13 quantitative trait loci associated with superior fiber quality. These resources will accelerate evolutionary and functional genomic studies in cotton and inform future breeding programs for fiber improvement.

Sin3a-Tet1 interaction activates gene transcription and is required for embryonic stem cell pluripotency.

Sin3a is a core component of histone-deacetylation-activity-associated transcriptional repressor complex, playing important roles in early embryo development. Here, we reported that down-regulation of Sin3a led to the loss of embryonic stem cell (ESC) self-renewal and skewed differentiation into mesendoderm lineage. We found that Sin3a functioned as a transcriptional coactivator of the critical Nodal antagonist Lefty1 through interacting with Tet1 to de-methylate the Lefty1 promoter. Further studies showed that two amino acid residues (Phe147, Phe182) in the PAH1 domain of Sin3a are essential for Sin3a-Tet1 interaction and its activity in regulating pluripotency. Furthermore, genome-wide analyses of Sin3a, Tet1 and Pol II ChIP-seq and of 5mC MeDIP-seq revealed that Sin3a acted with Tet1 to facilitate the transcription of a set of their co-target genes. These results link Sin3a to epigenetic DNA modifications in transcriptional activation and have implications for understanding mechanisms underlying versatile functions of Sin3a in mouse ESCs.

Low expression level of HMBOX1 in high-grade serous ovarian cancer accelerates cell proliferation by inhibiting cell apoptosis.

Homeobox-containing 1 (HMBOX1) has been described as a transcription factor involved in the occurrence of some tumors, but its roles in ovarian cancer have never been reported. Here we aimed to investigate the roles of HMBOX1 on high-grade serous ovarian carcinoma (HGSOC). In this present study, HMBOX1 expression was decreased in HGSOC tissues and ovarian cancer cell lines (HO8910 and A2780) compared with ovarian surface epithelial tissues or normal human ovarian surface epithelial cell line (HOSEpiC). The cell proliferation of HOSEpiC was weaker than ovarian cancer cell lines. By altering the expression of HMBOX1 in A2780 and HOSEpiC, we demonstrated that HMBOX1 inhibited the cell proliferation and promoted the cell apoptosis. Furthermore, our study revealed that HMBOX1 downregulated the expression of anti-apoptotic proteins (Bcl-2, Bcl-xL), raised the expression of pro-apoptotic-regulated proteins (Bad, Bax), apoptotic executionior (Caspase3), and P53. In conclusion, HMBOX1 played important roles in occurrence of HGSOC through regulation of proliferation and apoptosis, which implied that HMBOX1 might serve as a new therapeutic target for HGSOC.

SGK1 inhibition-induced autophagy impairs prostate cancer metastasis by reversing EMT.

BACKGROUND: Despite SGK1 has been identified and characterized as a tumor-promoting gene, the functions and underlying mechanisms of SGK1 involved in metastasis regulation have not yet been investigated in cancer. METHODS: We investigated the cellular responses to GSK650394 treatment and SGK1 silencing (or overexpression) in human prostate cancer (PCa) cell lines and PC3 xenografts by wound healing assay, migration and invasion assay, western blotting, immunofluorescence and immunohistochemistry. RESULTS: In the present study, we found that SGK1 expression positively correlates with human prostate cancer (PCa) progression and metastasis. We show that SGK1 inhibition significantly attenuates EMT and metastasis both in vitro and in vivo, whereas overexpression of SGK1 dramaticlly promoted the invasion and migration of PCa cells. Our further results suggest that SGK1 inhibition induced antimetastatic effects, at least partially via autophagy-mediated repression of EMT through the downregulation of Snail. Moreover, ectopic expression of SGK1 obviously attenuated the GSK650394-induced autophagy and antimetastatic effects. What's more, dual inhibition of mTOR and SGK1 enhances autophagy and leads to synergistic antimetastatic effects on PCa cells. CONCLUSIONS: Taken together, this study unveils a novel mechanism in which SGK1 functions as a tumor metastasis-promoting gene and highlights how co-targeting SGK1 and autophagy restrains cancer progression due to the amplified antimetastatic effects.

SGK1 inhibition induces autophagy-dependent apoptosis via the mTOR-Foxo3a pathway.

BACKGROUND: Although inhibition of SGK1 has been shown to delay cancer progression, the underlying mechanisms have not yet been elucidated. METHODS: We investigated the cellular responses to GSK650394 treatment and SGK1 silencing (or overexpression) in human prostate cancer (PCa) cell lines and PC3 xenografts by flow cytometry, western blotting, immunofluorescence, transmission electron microscopy and immunohistochemistry. RESULTS: In the present study, we demonstrated that SGK1 inhibition, mediated by either GSK650394 or SGK1 shRNA, induced G2/M arrest, apoptosis and autophagy. Furthermore, 3MA-mediated autophagy inhibition attenuated SGK1 inhibition-induced apoptosis, suggesting that induction of autophagy precedes apoptosis. Moreover, ectopic expression of SGK1 significantly attenuated the GSK650394-induced effects. Suppression of mTOR and Foxo3a phosphorylation is critical for blockade of SGK1-induced autophagy and apoptosis, at least partially via pFoxo3a (S253)-LC3 and pFoxo3a (S253)-p27 interactions. Dual inhibition of mTOR and SGK1 enhances autophagy activation and leads to synergistic cytocidal effects in PCa cells. CONCLUSIONS: In summary, our findings show that SGK1 inhibition exhibits significant antitumour effects against PCa in vitro and in vivo. This study uncovered a novel mechanism of SGK1 inhibition in PCa, which is mediated, at least in part, by inducing autophagy-dependent apoptosis via the mTOR-Foxo3a pathway.

RON and c-Met facilitate metastasis through the ERK signaling pathway in prostate cancer cells.

Prostate cancer (PCa) is a metastatic malignant cancer driven by complex pathological mechanisms and characterized by poor long-term prognosis. Metastasis is the main cause of death of PCa patients, yet the molecular mechanisms of this process are poorly understood. In the present study, positive co-expression of RON and c-Met was observed in human clinical PCa tissues (biopsy material), as detected by immunohistochemical staining and quantitative real-time PCR. We investigated this further in PCa cells, demonstrating that the inhibition of RON and c-Met with foretinib (GSK1363089) suppressed metastasis and promoted the reversal of the epithelial-to-mesenchymal transition (EMT) in PCa cells. Furthermore, the invasion and migration of PCa cells were enhanced by the exogenous activation of RON with MSP and c-Met with HGF, whereas silencing of RON and c-Met attenuated the invasion and metastasis of the PCa cells. Our data also demonstrated that HGF/c-Met, but not the MSP-RON signaling pathway may be the dominant mechanism for PCa EMT. We further revealed that RON and c-Met facilitate metastasis via ERK1/2 signaling. These findings indicate that RON and c-Met facilitate metastasis through ERK1/2 signaling and that targeting RON and c-Met with foretinib may be an attractive therapeutic option for suppressing PCa metastasis.