KLF9, a transcription factor induced in flutamide-caused cell apoptosis, inhibits AKT activation and suppresses tumor growth of prostate cancer cells

Genome-Wide Identification, Evolution, and miRNA-22 Regulation of Kruppel-Like Factor (KLF) Gene Family in Chicken (Gallus gallus)

Krüppel-like factors (KLFs) are a class of fundamental transcription factors that are widely present in various eukaryotes from nematodes to humans, named after their DNA binding domain which is highly homologous to the Krüppel factor in fruit flies. To investigate the composition, organization, and evolutionary trajectory of KLF gene family members in chickens, in our study, we leveraged conserved sequences of KLF genes from representative classes across fish, amphibians, birds, and mammals as foundational sequences. Bioinformatic tools were employed to perform homology alignment on the chicken genome database, ultimately identifying the KLF family members present in chickens. The gene structure, phylogenetic analysis, conserved base sequences, physicochemical properties, collinearity analysis, and protein structure were then analyzed using bioinformatic tools. Additionally, the impact of miRNA-22, related to poultry lipid metabolism, on the expression of the KLF gene family in the liver, heart, and muscle of Qingyuan partridge chickens was explored. The results showed that: (1) compared to fish, the KLF family in birds is more closely related to mammals and amphibians; (2) KLFs within the same subgroups are likely to be derived from a common ancestral gene duplication; (3) KLF3/8/12 in the same subgroup may have some similar or overlapping functions; (4) the motif 4 of KLF5 was most likely lost during evolution; (5) KLF9 may perform a similar function in chickens and pigs; (6) there are collinear relationships between certain KLF genes, indicating that there are related biomolecular functions between these KLF genes; (7) all members of the KLF family in chickens are non-transmembrane proteins; and (8) interference and overexpression of miRNA-22 in Qingyuan partridge chickens can affect the expression levels of KLF genes in liver, heart, and muscle.

The kruppel-like factor (KLF) family, diseases, and physiological events

The Kruppel-Like Factor family of regulatory proteins, which has 18 members, is transcription factors. This family contains zinc finger proteins, regulates the activation and suppression of transcription, and binds to DNA, RNA, and proteins. Klfs related to the immune system are Klf1, Klf2, Klf3, Klf4, Klf6, and Klf14. Klfs related to adipose tissue development and/or glucose metabolism are Klf3, Klf7, Klf9, Klf10, Klf11, Klf14, Klf15, and Klf16. Klfs related to cancer are Klf3, Klf4, Klf5, Klf6, Klf7, Klf8, Klf9, Klf10, Klf11, Klf12, Klf13, Klf14, Klf16, and Klf17. Klfs related to the cardiovascular system are Klf4, Klf5, Klf10, Klf13, Klf14, and Klf15. Klfs related to the nervous system are Klf4, Klf7, Klf8, and Klf9. Klfs are associated with diseases such as carcinogenesis, oxidative stress, diabetes, liver fibrosis, thalassemia, and the metabolic syndrome. The aim of this review is to provide information about the relationship of Klfs with some diseases and physiological events and to guide future studies.

Krüppel-like Factor-9 and Krüppel-like Factor-13: Highly Related, Multi-Functional, Transcriptional Repressors and Activators of Oncogenesis

Specificity Proteins/Krüppel-like Factors (SP/KLF family) are a conserved family of transcriptional regulators. These proteins share three highly conserved, contiguous zinc fingers in their carboxy-terminus, requisite for binding to cis elements in DNA. Each SP/KLF protein has unique primary sequence within its amino-terminal and carboxy-terminal regions, and it is these regions which interact with co-activators, co-repressors, and chromatin-modifying proteins to support the transcriptional activation and repression of target genes. Krüppel-like Factor 9 (KLF9) and Krüppel-like Factor 13 (KLF13) are two of the smallest members of the SP/KLF family, are paralogous, emerged early in metazoan evolution, and are highly conserved. Paradoxically, while most similar in primary sequence, KLF9 and KLF13 display many distinct roles in target cells. In this article, we summarize the work that has identified the roles of KLF9 (and to a lesser degree KLF13) in tumor suppression or promotion via unique effects on differentiation, pro- and anti-inflammatory pathways, oxidative stress, and tumor immune cell infiltration. We also highlight the great diversity of miRNAs, lncRNAs, and circular RNAs which provide mechanisms for the ubiquitous tumor-specific suppression of KLF9 mRNA and protein. Elucidation of KLF9 and KLF13 in cancer biology is likely to provide new inroads to the understanding of oncogenesis and its prevention and treatments.

Chrysosplenol D can inhibit the growth of prostate cancer by inducing reactive oxygen species and autophagy

OBJECTIVE

To uncover the effects of chrysosplenol D (CHD) on the progression of prostate cancer in vitro as well as in mice.

METHODS

DU145 and PC-3 cells were treated with increasing doses of CHD for 24, 48, or 72 h. Cell Counting Kit-8 (CCK-8) and colony formation assays were conducted to confirm the effects of CHD on cell viability. Flow cytometry (FCM) and immunostaining assays showed the effects of CHD on cell apoptosis and oxidative stress. Immunoblot was performed to detect the effects of CHD on autophagy. Besides, tumor growth assays were conducted to confirm the role of CHD in tumor growth in mice. GraphPad 6.0 was used for statistical analysis. All data were represented as mean ± SD. p < .05 and the significant difference was indicated by an asterisk.

RESULTS

CHD suppressed the viability of prostate cancer cells in CCK-8 assays, decreased colony number in colony formation assays, and induced cell apoptosis in FCM and immunostaining assays. CHD also restrained the oxidative stress with a decreased 2'-7'-dichlorofluorescein diacetate staining intensity. CHD restrained the autophagy of prostate cancer cells, as well as suppressed tumor growth in mice.

CONCLUSION

CHD could serve as a drug for prostate cancer.

PM2.5 leads to adverse pregnancy outcomes by inducing trophoblast oxidative stress and mitochondrial apoptosis via KLF9/CYP1A1 transcriptional axis

Epidemiological studies have demonstrated that fine particulate matter (PM2.5) is associated with adverse obstetric and postnatal metabolic health outcomes, but the mechanism remains unclear. This study aimed to investigate the toxicological pathways by which PM2.5 damaged placental trophoblasts in vivo and in vitro. We confirmed that PM2.5 induced adverse gestational outcomes such as increased fetal mortality rates, decreased fetal numbers and weight, damaged placental structure, and increased apoptosis of trophoblasts. Additionally, PM2.5 induced dysfunction of the trophoblast cell line HTR8/SVneo, including in its proliferation, apoptosis, invasion, migration and angiogenesis. Moreover, we comprehensively analyzed the transcriptional landscape of HTR8/SVneo cells exposed to PM2.5 through RNA-Seq and observed that PM2.5 triggered overexpression of pathways involved in oxidative stress and mitochondrial apoptosis to damage HTR8/SVneo cell biological functions through CYP1A1. Mechanistically, PM2.5 stimulated KLF9, a transcription factor identified as binding to CYP1A1 promoter region, which further modulated the CYP1A1-driven downstream phenotypes. Together, this study demonstrated that the KLF9/CYP1A1 axis played a crucial role in the toxic progression of PM2.5 induced adverse pregnancy outcomes, suggesting adverse effects of environmental pollution on pregnant females and putative targeted therapeutic strategies.

SCARB1 in extracellular vesicles promotes NPC metastasis by co-regulating M1 and M2 macrophage function

Distant metastasis is currently the main factor affecting the prognosis of nasopharyngeal carcinoma (NPC), and understanding the mechanisms of metastasis and identifying reliable therapeutic targets are critical for improving prognosis and achieving clinical translation. Macrophages, as important immune cells in the tumor microenvironment (TME), have been shown to regulate metastasis. And extracellular vesicles (EVs) secreted by stromal cells and tumor cells play the important role in intercellular communication in the tumor microenvironment. However, the role of NPC-EVs on macrophages and their function in regulating macrophages to affect metastasis has not been fully clarified. In this study, we report that NPC-EVs can be uptake by macrophages and alter macrophage polarization, for the first time, we identified the genes implicated in these regulatory functions: SCARB1, HAAO, and CYP1B1. Moreover, we found that SCARB1 was positively associated with metastasis and poor prognosis of NPC. Interestingly, we found that SCARB1-rich EVs promoted M1 macrophages ferroptosis to decrease M1 macrophages infiltration by upregulating the HAAO level while decreasing phagocytosis of M2 macrophages by upregulating the CYP1B1 level. Finally, we identified the SCARB1-binding gene KLF9, which is involved in the transcription of HAAO and CYP1B1. Our findings showed that SCARB1-EVs promoted metastasis by co-regulating M1 and M2 macrophage function. The related mechanism will provide a new therapeutic strategy to help patients with NPC improve their prognosis.

Krüppel-like factors in tumors: Key regulators and therapeutic avenues

Krüppel-like factors (KLFs) are a group of DNA-binding transcriptional regulators with multiple essential functions in various cellular processes, including proliferation, migration, inflammation, and angiogenesis. The aberrant expression of KLFs is often found in tumor tissues and is essential for tumor development. At the molecular level, KLFs regulate multiple signaling pathways and mediate crosstalk among them. Some KLFs may also be molecular switches for specific biological signals, driving their transition from tumor suppressors to promoters. At the histological level, the abnormal expression of KLFs is closely associated with tumor cell stemness, proliferation, apoptosis, and alterations in the tumor microenvironment. Notably, the role of each KLF in tumors varies according to tumor type and different stages of tumor development rather than being invariant. In this review, we focus on the advances in the molecular biology of KLFs, particularly the regulations of several classical signaling pathways by these factors, and the critical role of KLFs in tumor development. We also highlight their strong potential as molecular targets in tumor therapy and suggest potential directions for clinical translational research.

LncRNA TPTEP1 inhibits the migration and invasion of gastric cancer cells through miR-548d-3p/KLF9/PER1 axis

BACKGROUND

Despite the development of many methods and new therapeutic agents, the survival and prognosis of patients with gastric cancer are still poor. The role of TPTEP1 in gastric cancer has not been reported.

METHODS

Wound healing assay and transwell assay analysis TPTEP1/miR-548d-3p/KLF9/PER1 effect on migration and invasiveness of gastric cells. Western blot and RT-qPCR certificate TPTEP1/miR-548d-3p/KLF9/PER1transcription and expression of migration and invasion related genes. Luciferase assay was used to determine the adsorption of miR-548d-3p by TPTEP1 sponge, the targeting of miR-548d-3p to KLF9, and the binding of KLF9 to the promoter of PER1. immunohistochemical assay and H&E staining prove the function of TPTEP1 and miR-548d-3p in nude mice model of gastric cancer.

RESULTS

TPTEP1 inhibited its expression by sponge adsorption of miR-548d-3p. miR-548d-3p targets KLF9 3'UTR to inhibit its expression, and KLF9 binds to the PER1 promoter to promote its expression.TPTEP1/KLF9/PER1 inhibits gastric cancer cell migration and invasion, and miR-548d-3p does the opposite.

CONCLUSIONS

Our data suggest that TPTEP1 affects gastric cancer progression by regulating the miR-548d-3p/KLF9/PER1 axis. Targeting this pathway may provide new therapeutic opportunities for gastric cancer.

Krüppel-like factors in bone biology

The krüppel-like factor (KLF) family is a group of zinc finger transcription factors and contributes to different cellular processes such as differentiation, proliferation, migration, and apoptosis. While different studies show the roles of this family in skeletal development-specifically in chondrocyte and osteocyte development and bone homeostasis-there are few reviews summarizing their importance. To fill this gap, this review discusses current knowledge on different functions of the KLF family during skeletal development, including their roles in stem cell maintenance and differentiation, cell apoptosis, and cell cycle. To understand the importance of the KLF family, we also review genotype-phenotype correlations in different animal models. We also discuss how KLF proteins function through different signaling pathways and display their paramount importance in skeletal development. To highlight their roles in cartilage- or bone-related cells, we also use single-cell RNA sequencing publicly available data on mouse hindlimb. We also challenge our knowledge of how the KLF family is epigenetically regulated-e.g., using DNA methylation, histone modifications, and noncoding RNAs-during chondrocyte and osteocyte development.

Novel combination therapy of prostate cancer cells with arsenic trioxide and flutamide: An in-vitro study

OBJECTIVE

The study objective was to assess the therapeutic potential of Arsenic Trioxide (ATO) and Flutamide combination for metastatic prostate cancer (PCa) treatment.

MATERIAL AND METHOD

LNCaP and PC3 cell lines were treated with different concentrations of ATO and PCa conventional drug Flutamide alone and/or in combination to find effective doses and IC₅₀ values. Percentages of apoptotic cells were evaluated by Annexin/PI staining and the proliferative inhibitory effect was assessed by Micro Culture Tetrazolium Test (MTT). Expression of SNAIL, KLK2, E-cadherin, and angiogenesis genes (VEGFA and VEGFC), and apoptosis genes (Bcl₂, and P53) were examined by real-time PCR.

RESULTS

The combination of Flutamide and ATO significantly increased the percentage of apoptotic cells and inhibited PCa cells proliferation compared with each drug alone in LNCaP and PC3 cell lines. Generally, both cell lines treated with the combination of Flutamide and ATO showed a decrease in expression of KLK2, angiogenesis genes (VEGFA and VEGFC), and apoptosis gene (Bcl₂), and an increase in expression of E-cadherin and P53 genes; however, contradictory findings were found regarding SNAIL expression in LNCaP and PC3 cells.

CONCLUSION

The combination therapy with ATO and flutamide has augmented the anti-tumor effect on LNCaP and PC3 cells, which probably originates from their potential to induce apoptosis and inhibit the proliferation of PCa cells simultaneously.

KLF9 suppresses cell growth and induces apoptosis via the AR pathway in androgen-dependent prostate cancer cells

Kruppel-like factors (KLFs) play an important role in many biological processes including cell proliferation, differentiation and development. Our study showed that the level of KLF9 is lower in PCa cell lines compared to a benign prostate cell line; the androgen-independent cell line PC3 expresses significantly lower KLF9 than the androgen-dependent cell line, LNCaP. Forced overexpression of KLF9 suppressed cell growth, colony formation, and induced cell apoptosis in LNCaP cells. We also found that KLF9 expression was induced in response to apoptosis caused by flutamide, and further addition of dihydrotestosterone antagonized the action of flutamide and significantly decreased KLF9 expression. Furthermore, activation of the androgen receptor (AR) was inhibited by the overexpression of KLF9. Our research shows that KLF9 is lower in androgen-independent cell lines than in androgen-dependent cell lines; Overexpression of KLF9 dramatically suppresses the proliferation, anchorage-independent growth, and induces apoptosis in androgen-dependent cells; KLF9 inhibition on prostate cancer cell growth may be acting through the AR pathway. Our results therefore suggest that KLF9 may play a significant role in the transition from androgen-dependent to androgen-independent prostate cancer and is a potential target of prevention and therapy.

•

KLF9 is lower in androgen-independent cell lines than in androgen-dependent cell lines.

•

Overexpression of KLF9 suppresses the proliferation and induces apoptosis in androgen-dependent cells.

•

KLF9 inhibition on androgen-dependent Pca growth may be associated with the inhibition of AR pathway.

Loss of Krüppel-like factor 9 facilitates stemness in ovarian cancer ascites-derived multicellular spheroids via Notch1/slug signaling

The ascites that develops in advanced OC, both at diagnosis and upon recurrence, is a rich source of multicellular spheroids/aggregates (MCSs/MCAs), which are the major seeds of tumor cell dissemination within the abdominal cavity. However, the molecular mechanism by which specific ascites-derived tumor cells survive and metastasize remains largely unknown. In this study, we elucidated cancer stem cell (CSC) properties of ascites-derived MCSs, concomitant with enhanced malignancy, induced EMT, and low KLF9 (Krüppel-like factor 9) expression, compared with PTCs. KLF9 was also downregulated in OC cell line-derived spheroids and the CD117⁺ CD44⁺ subpopulation in MCSs. Functional experiments demonstrated that KLF9 negatively modulated stem-like properties in OC cells. Mechanistic studies revealed that KLF9 reduced the transcriptional expression of Notch1 by directly binding to the Notch1 promoter, thereby inhibiting the function of slug in a CSL-dependent manner. Clinically, expression of KLF9 was associated with histological grade and loss of KLF9 predicts poor prognosis in OC.

miR-483-3p, Mediated by KLF9, Functions as Tumor Suppressor in Testicular Seminoma via Targeting MMP9

Background

Seminoma (SEM) is the most frequent testicular germ cell tumor with a high incidence in young men. The present study aims to explore the function and regulatory mechanism of miR-483-3p in SEM.

Methods

RT-qPCR was performed to investigate miR-483-3p levels in SEM tissues. The effect of miR-483-3p on TCam-2 cells was assessed by CCK-8, colony formation, cell migration, and invasion assays. Luciferase reporter assays were performed to investigate the interaction between miR-483-3p and MMP9, and then the recovery experiments were performed. Moreover, the potential upstream regulator of miR-483-3p was predicted based on JASPAR database.

Results

miR-483-3p was down-regulated in SEM tissues versus paracancerous normal tissues. The expression level of miR-483-3p was significantly associated with tumor stage by RT-qPCR. Functionally, miR-483-3p over-expression suppressed cell growth, migration, and invasion in SEM cell lines. Mechanically, miR-483-3p negatively regulated MMP9 by directly binding to its 3′-UTR. The over-expression of miR-483-3p could reverse the promoting role of MMP9 over-expression on the proliferation, migration, and invasion of TCam-2 cells. Moreover, KLF9 was identified as a potential upstream regulator of miR-483-3p and functions as a tumor suppressor.

Conclusions

In general, our study suggested that miR-483-3p could inhibit the cell growth, migration, and invasion of testicular SEM by targeting MMP9. Moreover, KLF9 is an upstream positive regulator of miR-483-3p and also functions as a tumor suppressor in SEM.

PDK4 promotes tumorigenesis and cisplatin resistance in lung adenocarcinoma via transcriptional regulation of EPAS1

The use of cisplatin for the treatment of non-small cell lung cancer has long been constrained by the rapid acquisition of tumor cell chemoresistance. In the present study, we sought to better elucidate the molecular mechanisms underlying this resistance phenotype. To that end, we assessed gene expression patterns in cisplatin-resistant lung adenocarcinoma cells, revealing pyruvate dehydrogenase lipoamide kinase isozyme 4 (PDK4) to be the most up-regulated kinase in resistant cells. We further found PDK4 upregulation to be directly linked with the acquisition of chemoresistance, driving enhanced tumor cell growth in vitro and in vivo. In clinical samples, we also found that PDK4 upregulation was detectable in patients with lung adenocarcinoma and that it was correlated with a poorer prognosis for these patients. From a mechanistic perspective, we further determined that PDK4 was able to promote lung adenocarcinoma cell growth and cisplatin resistance at least in part via regulating endothelial PAS domain-containing protein 1 (EPAS1) expression, thus highlighting PDK4 as a potentially viable therapeutic target in efforts to treat lung adenocarcinoma patients that have become resistant to cisplatin.

Functional Specialization of Human Salivary Glands and Origins of Proteins Intrinsic to Human Saliva

Salivary proteins are essential for maintaining health in the oral cavity and proximal digestive tract, and they serve as potential diagnostic markers for monitoring human health and disease. However, their precise organ origins remain unclear. Through transcriptomic analysis of major adult and fetal salivary glands and integration with the saliva proteome, the blood plasma proteome, and transcriptomes of 28+ organs, we link human saliva proteins to their source, identify salivary-gland-specific genes, and uncover fetal- and adult-specific gene repertoires. Our results also provide insights into the degree of gene retention during gland maturation and suggest that functional diversity among adult gland types is driven by specific dosage combinations of hundreds of transcriptional regulators rather than by a few gland-specific factors. Finally, we demonstrate the heterogeneity of the human acinar cell lineage. Our results pave the way for future investigations into glandular biology and pathology, as well as saliva's use as a diagnostic fluid.

MicroRNA-652 promotes cell proliferation and osteosarcoma invasion by directly targeting KLF9

Previous studies have demonstrated that various microRNAs (miRNAs or miRs) are abnormally expressed in osteosarcoma (OS) and serve roles in its malignant development. An in-depth understanding of the specific roles of dysregulated miRNAs in OS may be important for cancer research and the identification of novel therapeutic targets. In the current study, reverse transcription-quantitative PCR was performed to determine miR-652 expression in OS tissues and cell lines. Cell Counting Kit-8 and Transwell invasion assays were used for assessing the effect of miR-652 on the proliferation and invasion of OS cells. Herein, miR-652 expression was assessed in OS and the effects and molecular mechanisms of miR-652 in OS cells were examined. The results revealed that miR-652 expression was significantly upregulated in OS tissues and cell lines compared with adjacent normal tissues and a normal human osteoblast cell line. Furthermore, miR-652 downregulation inhibited the proliferation and invasion of OS cells. miR-652 was also demonstrated to directly interact with the 3'-untranslated region of kruppel-like factor 9 (KLF9) and miR-652 negatively regulated KLF9 expression in OS cells. miR-652 and KLF9 mRNA levels were also revealed to be inversely correlated in OS tissues. Treatment with KLF9 small interfering RNA abolished the suppression of OS proliferation and invasion induced by miR-652 downregulation. miR-652 may serve an oncogenic role in OS cells by targeting KLF9 directly. The results also indicated that miR-652 may be an effective novel therapeutic target for the treatment of patients with OS.

Expression of Krüppel-like factor 9 in breast cancer patients and its effect on prognosis

Expression of Krüppel-like factor 9 (KLF9) in breast cancer tissue and its influence on prognosis was investigated. Sixty-eight patients with breast cancer admitted in Ningde Hospital Affiliated to Fujian Medical University from February 2014 to August 2015 were collected, and the expression level of KLF9 in cancerous tissue (n=68) and normal tissue (n=68) of the patients was measured by quantitative real-time PCR (RT-qPCR). The relationship between the expression and clinical pathological features and prognosis of patients was analyzed. The expression level of KLF9 in cancerous tissue was significantly lower than that in normal tissue (P<0.05). The expression in breast cancer tissue was not significantly correlated with age, height, menstrual status, lymph node metastasis or pathological differentiation (P>0.05), but was significantly correlated with tumor size and clinical stage (P<0.05). The 1-, 2-, and 3-year survival rates in the high expression group were significantly higher than those in the low expression group (P<0.001). Univariate Cox regression analysis was carried out according to the 3-year survival of the patients, and the results showed that tumor size (P=0.009), lymph node metastasis (P=0.002), pathological differentiation (P=0.015), clinical stage (P=0.013), and KLF9 (P=0.018) were factors affecting the survival of breast cancer patients. Subsequently, multivariate Cox regression analysis of the indicators with differences showed that those indicators were independent predictors of survival of breast cancer patients. In conclusion, KLF9 expression is low in breast cancer tissue, and its expression level is related to tumor size and clinical stage. Moreover, tumor size >5 cm, lymph node metastasis, low pathological differentiation, high clinical stage and low expression of KLF9 are all important factors that cause death of patients.

Characterization of the prognostic values and response to immunotherapy/chemotherapy of Krüppel-like factors in prostate cancer

At present, the overall genetic and epigenetic effects of Krüppel‐like factors (KLFs) on prostate cancer (PCa) remain unclear. Therefore, we systematically investigated the molecular differences in KLFs of transcription expression, promoter methylation and genetic alteration. Univariate and multivariate Cox proportional hazard regression was used to analyse the effect on RFS and establish the prognostic signature in the TCGA cohort, MSKCC and GSE116918 cohorts employed to validate the signature. Biological pathway enrichment and the potential response to immunotherapy and chemotherapy were inferred. The transcription levels of most KLFs are associated with the clinical outcome of PCa. Gleason score (P = .009), pathology T stage (P = .006), KLF3 (P = .034), KLF5 (P = .002) and KLF7 (P = .035) were independent prognostic factors. A prognostic signature was established in the TCGA cohort (P < .001) and validated in the MSKCC (P < .001) and GSE116918 cohorts (P = .006). Demethylation of KLF5 by 5‐azacytidine led to increased protein levels, whereas knockdown of KLF5 promoted cell proliferation. Patients in KLF‐F were more likely to respond to immunotherapy (P < .001) and bicalutamide (P < .001). In summary, we found that the KLFs and clinical feature‐based signatures may improve prognosis prediction in PCa and further promote patient stratification and disease management.

KLF16 Affects the MYC Signature and Tumor Growth in Prostate Cancer

Background

KLF16, a member of the Kruppel-like factor (KLF) family, functions in the regulation of dopaminergic transmission, metabolism, and endocrinology. However, the role of KLF16 in prostate cancer (PCa) remains unknown.

Methods

We screened the expression of KLFs in PCa based on bioinformatics analysis. The protein levels of KLF16 in PCa specimens were confirmed by immunohistochemistry. Inhibiting KLF16 by RNA interference with shRNA was used to determine the effects of KLF16 on PCa cell growth in vitro and in vivo. RNA sequencing was used to investigate the signaling regulated by KLF16 in PCa. Bioinformatics analysis was also used to determine the possible correlations of KLF16 and signaling in PCa cohorts.

Results

Bioinformatics analysis showed that KLF16 may be required for PCa development. Notably, the expression of KLF16 was elevated in human PCa tissues. In vitro and in vivo experiments both demonstrated that depleting KLF16 significantly inhibited the growth of PCa cells. Downregulation of KLF16 significantly decreased the expression of MYC signaling in PCa cells. Furthermore, KLF16 expression was correlated with MYC signaling activity.

Conclusion

KLF16 was overexpressed in PCa tissues compared to normal tissues. KLF16 knockdown suppressed PCa cell growth in vitro and in vivo, and a deficiency of KLF16 inhibited activation of MYC signaling.

Molecular mechanisms of TUG1 in the proliferation, apoptosis, migration and invasion of cancer cells

Long non-coding RNAs (lncRNAs) are RNA sequences >200 nucleotides in length that have no protein-coding capacity. lncRNAs serve key roles in multiple biological processes, such as tumorigenesis and tumor progression. Taurine upregulated 1 (TUG1) is a novel lncRNA that has been associated with human cancer. TUG1 has attracted increasing attention in recent years and has been documented to be abnormally expressed in different types of cancer. Numerous studies indicate that TUG1 may be significantly associated with tumor development and cell metabolism by regulating cell proliferation, invasion, metastasis, apoptosis, differentiation and drug resistance. TUG1 exerts its function via recruiting specific RNA-binding proteins, promoting target gene expression, influencing tumor angiogenesis and by functioning as a competing endogenous RNA (ceRNA). An increasing number of studies have demonstrated that ceRNAs serve a role in cancer development. TUG1 is considered to be a biomarker or a novel therapeutic target for the diagnosis and prognosis of different cancer types. The present review focuses on recent developments in the major underlying molecular mechanisms of TUG1 in cancer, including its role in cell proliferation, apoptosis, migration, invasion and drug resistance. Also discussed in the present review is the current knowledge regarding the regulation of TUG1.

Targeting POH1 inhibits prostate cancer cell growth and enhances the suppressive efficacy of androgen deprivation and docetaxel

BACKGROUND

POH1, a member of the JAMM domain containing deubiquitinases, functions in malignant progression of certain types of cancer. However, the role of POH1 in prostate cancer (PCa) remains unclear.

METHODS

We performed RNA interference against the JAMM members in PC3 cells and analyzed cell proliferation. POH1 knockdown was established to evaluate the effects of POH1 on cell growth in vitro and in vivo. RNA-sequencing was utilized to explore the molecular details underlying the biological function of POH1 in PCa. The expression of POH1 in PCa tissues was detected by immunohistochemistry. The POH1 inhibitor capzimin was evaluated to explore whether pharmacologically inhibiting POH1 significantly affected PCa cell proliferation alone or enhanced the inhibitory efficacy of docetaxel and androgen deprivation.

RESULTS

Functional analyses identified POH1 as a JAMM deubiquitinase that is required for PCa proliferation. Importantly, expression of POH1 was higher in human PCa tissues (PCas) than that in normal prostate tissues, and a positive correlation was detected between elevated POH1 expression and higher pathological grades in PCas. In vivo experiments further demonstrated that depleting POH1 significantly suppressed the growth of PCa cell xenografts. POH1 deficiency profoundly inhibited the expression of a set of genes involving the cell cycle and caused G0/G1 phase arrest. Furthermore, the POH1 inhibitor capzimin phenotypically recapitulated the effects of POH1 knockdown and improved the efficacy of docetaxel and androgen deprivation in PCa cells.

CONCLUSIONS

POH1 was overexpressed in PCas and was correlated with pathological grades in human PCas. Inhibiting POH1 by gene silencing or pharmacological inhibition with capzimin suppressed PCa cell growth. Exploring the inhibition of POH1 in combination with other drugs may provide a strategy to benefit patients with PCa.

Molecular cloning and characterization of grouper Krϋppel-like factor 9 gene: Involvement in the fish immune response to viral infection

Krϋppel-like factor 9 (KLF9) is a member of the SP/KL family, which are transcription factors implicated in several biological processes, including cell proliferation, differentiation, development and apoptosis. Studies have focused on the function of KLF9 in mammalian disease and the immune system, such as its regulatory role in the growth of tumors and its impact on interferon-related genes and inflammatory cytokines. In fish, little is known about the role of KLF9, especially its regulatory function in the innate antiviral immune response. In this study, we characterized the grouper KLF9 gene (EcKLF9) and investigated its role in viral infection. Amino acid alignment analysis showed that EcKLF9 was approximately 228 amino acids long and contained a typical three-tandem Krϋppel-like zinc fingers. Phylogenetic tree analysis revealed that EcKLF9 clustered with three fish species: Amphiprion ocellaris, Acanthochromis pollyacanthus and Stegastes partitus. Comparison analyses showed that the three Kruppel-like zinc finger domains of KLF9 were highly conserved in different fish species. Tissue expression analysis showed that EcKLF9 was constitutively expressed in all 12 tissues tested, in the healthy grouper, the highest expression being detected in the gonads. The relative expression levels of EcKLF9 in the head kidney, spleen and brain was significantly increased during red-spotted grouper nervous necrosis virus (RGNNV) and Singapore grouper iridovirus (SGIV) infections. Using fluorescence microscopy, EcKLF9 was primarily localized to the nucleus and cytoplasm. The in vitro ectopic expression of EcKLF9 significantly increased the severity of vacuoles induced by RGNNV and the cytopathic effect progression evoked by SGIV infection. Real-time PCR results showed that the transcription levels of viral genes, such as the Singapore grouper iridovirus infection genes, MCP (major capsid protein), LITAF (lipopolysaccharide induced TNF-α factor), VP19 (envelop protein) ICP-18 (infected cell protein-18) and the red-spotted grouper nervous necrosis virus genes, CP (coat protein), RdRp (RNA-dependent RNA polymerase), were all significantly increased in EcKLF9 overexpressing cells, when compared to control cells. Furthermore, western blotting analyses showed that protein levels of the RGNNV gene, CP and the SGIV gene, MCP were also increased in EcKLF9 overexpressing cells, suggesting EcKLF9 may promote viral activity against iridovirus and nodavirus, in vitro. Moreover, the overexpression of EcKLF9 significantly inhibited the expression of several interferon related cytokines and several inflammatory cytokines. Accordingly, we speculate that EcKLF9 may exert stimulatory effects on RGNNV and SGIV replication, through the negative regulation of host immune and inflammation responses.

THBS4 predicts poor outcomes and promotes proliferation and metastasis in gastric cancer

Gastric cancer (GC), a common and lethal cancer in the world, has a high risk of metastasis. Our study was to explore the effects of THBS4 on GC progress and metastasis and the underlying mechanisms. The proliferations of MGC-803 and BGC-823 cells were analyzed via cell count, MTT, and soft agar colony formation assay. The migration and invasion of transfected GC cells was investigated via transwell migration and invasion assay. The mRNA abundance of THBS4 and KLF9 was detected by quantitative real-time PCR (qPCR). The analysis of Gene Expression Omnibus (GEO) dataset (GSE26253) suggested that THBS4 was up-regulated in recurrent GC patients and was positively correlated with the increase in pathological stage and poor prognosis in GC. THBS4 stimulated the proliferations of GC cells. Moreover, THBS4 overexpression fostered the migration and invasion of GC cells. Further, the bioinformatics analysis of the cancer genome atlas dataset suggested that there may be a positive correlation between THBS4 and KLF9 expression. QPCR analysis proved that transfected with THBS4 overexpression plasmid enhanced KLF9 expression in GC cells. THBS4 mRNA and protein expression were up-regulated in MGC-803 and BGC-823 cells compared to those in non-tumoral gastric cells. KLF9 overexpression significantly stimulated the proliferation and metastasis of MGC-803 and BGC-823 cells. Besides, KLF9 siRNA inhibited the enhanced viability, migration, and invasion of MGC-803 cells caused by the transfection with THBS4 overexpression plasmid. In conclusion, THBS4 had positive effects on GC proliferation and metastasis via targeting KLF9.

Neural Transcription Factors in Disease Progression

Progression to the malignant state is fundamentally dependent on transcriptional regulation in cancer cells. Optimum abundance of cell cycle proteins, angiogenesis factors, immune evasion markers, etc. is needed for proliferation, metastasis or resistance to treatment. Therefore, dysregulation of transcription factors can compromise the normal prostate transcriptional network and contribute to malignant disease progression.The androgen receptor (AR) is considered to be a key transcription factor in prostate cancer (PCa) development and progression. Consequently, androgen pathway inhibitors (APIs) are currently the mainstay in PCa treatment, especially in castration-resistant prostate cancer (CRPC). However, emerging evidence suggests that with increased administration of potent APIs, prostate cancer can progress to a highly aggressive disease that morphologically resembles small cell carcinoma, which is referred to as neuroendocrine prostate cancer (NEPC), treatment-induced or treatment-emergent small cell prostate cancer. This chapter will review how neuronal transcription factors play a part in inducing a plastic stage in prostate cancer cells that eventually progresses to a more aggressive state such as NEPC.

KLF2 Inhibits the Migration and Invasion of Prostate Cancer Cells by Downregulating MMP2

KLF2, a member of the Kruppel-like factor (KLF) family, is thought to be a tumor suppressor in many kinds of malignant tumors. Its functions in prostate cancer (PCa) are unknown. This study aimed to explore the role of KLF2 in the migration and invasion of PCa cells. The expression of KLF2 was measured by immunohistochemistry in PCa tissues and in paired non-tumor tissues. KLF2 and MMP2 expression in cells was measured by Western blot and RT-qPCR. Adenoviruses and siRNAs were used in cell function tests to investigate the role of KLF2 in regulating MMP2. Interactions between KLF2 and MMP2 were analyzed by a luciferase activity assay. The present study, for the first time, identified that KLF2 was downregulated both in PCa clinical tissue samples and in cancer cell lines. The overexpression of KLF2 inhibited the migration and invasion of PCa cells via the suppression of MMP2.This study demonstrates that KLF2 might act as a tumor suppressor gene in PCa and that the pharmaceutical upregulation of KLF2 may be a potential approach for treatment.

MicroRNA‑940 promotes cell proliferation and invasion of glioma by directly targeting Kruppel‑like factor 9

MicroRNA‑940 (miR‑940) has been extensively studied in the pathogenesis of numerous types of human cancer; however, the expression pattern, roles and molecular mechanisms underlying the regulatory actions of miR‑940 in glioma remain unknown. The present study aimed to further investigate miR‑940 by studying its expression, roles and mechanisms of action in glioma. Reverse transcription‑quantitative polymerase chain reaction (RT‑qPCR) was used to detect miR‑940 expression in glioma tissues and cell lines. The regulatory effects of miR‑940 in glioma cell proliferation and invasion were determined using MTT and cell invasion assays. Bioinformatics analyses was performed to identify the potential target of miR‑940, which was further confirmed by luciferase reporter assay, RT‑qPCR and western blot analysis. In the present study, significantly increased miR‑940 expression levels were observed in glioma tissues and cell lines compared with normal brain tissues and normal human astrocytes, respectively. Decreased miR‑940 expression levels attenuated glioma cell proliferation and invasion in vitro. Kruppel‑like factor 9 (KLF9) was predicted as a potential target of miR‑940. Further assays demonstrated that miR‑940 negatively regulated KLF9 expression in glioma cells by directly targeting the 3'‑untranslated regions of KLF9. Additionally, KLF9 expression was downregulated in glioma tissues and was inversely correlated with miR‑940. Furthermore, KLF9 knockdown was able to rescue the effects of miR‑940 on glioma cell proliferation and invasion. The results of the present study suggest that miR‑940 may function as an oncogene in glioma by targeting KLF9 and may be a considered a therapeutic target for the treatment of gliomas.

LncRNA SNHG3 enhances the malignant progress of glioma through silencing KLF2 and p21

As a newly discovered long non-coding RNA, small nucleolar RNA host gene 3 (SHNG3) has been reported to be dysregulated in certain cancers. Nevertheless, the details about clinical values and biological effects of SNHG3 on glioma are still covered. In this paper, we determined the expression level of SNHG3 in glioma tissues and cells and evaluated the effect of SNHG3 expression on the prognosis of glioma patients. The functional assays were applied to define the effects of SNHG3 on the biological behaviors in glioma including cell proliferation, cell cycle, and apoptosis. It was revealed that SNHG3 was much more enriched in glioma tissues and cell lines than in normal ones. Furthermore, gain- or loss-of-function experiments indicated that the up-regulation of SNHG3 promoted cell proliferation, accelerate cell cycle progress, and repressed cell apoptosis. The mechanistic assays disclosed that SNHG3 facilitated the malignant progression of glioma through epigenetically repressing KLF2 and p21 via recruiting enhancer of zeste homolog 2 to the promoter of KLF2 and p21. Generally, it was exposed that SNHG3 might function as an oncogene in glioma and could be explored as a potential prognostic biomarker and therapeutic target for glioma.

Glucocorticoids, genes and brain function

The identification of key genes in transcriptomic data constitutes a huge challenge. Our review of microarray reports revealed 88 genes whose transcription is consistently regulated by glucocorticoids (GCs), such as cortisol, corticosterone and dexamethasone, in the brain. Replicable transcriptomic data were combined with biochemical and physiological data to create an integrated view of the effects induced by GCs. The most frequently reported genes were Errfi1 and Ddit4. Their up-regulation was associated with the altered transcription of genes regulating growth factor and mTORC1 signaling (Gab1, Tsc22d3, Dusp1, Ndrg2, Ppp5c and Sesn1) and progression of the cell cycle (Ccnd1, Cdkn1a and Cables1). The GC-induced reprogramming of cell function involves changes in the mRNA level of genes responsible for the regulation of transcription (Klf9, Bcl6, Klf15, Tle3, Cxxc5, Litaf, Tle4, Jun, Sox4, Sox2, Sox9, Irf1, Sall2, Nfkbia and Id1) and the selective degradation of mRNA (Tob2). Other genes are involved in the regulation of metabolism (Gpd1, Aldoc and Pdk4), actin cytoskeleton (Myh2, Nedd9, Mical2, Rhou, Arl4d, Osbpl3, Arhgef3, Sdc4, Rdx, Wipf3, Chst1 and Hepacam), autophagy (Eva1a and Plekhf1), vesicular transport (Rhob, Ehd3, Vps37b and Scamp2), gap junctions (Gjb6), immune response (Tiparp, Mertk, Lyve1 and Il6r), signaling mediated by thyroid hormones (Thra and Sult1a1), calcium (Calm2), adrenaline/noradrenaline (Adcy9 and Adra1d), neuropeptide Y (Npy1r) and histamine (Hdc). GCs also affected genes involved in the synthesis of polyamines (Azin1) and taurine (Cdo1). The actions of GCs are restrained by feedback mechanisms depending on the transcription of Sgk1, Fkbp5 and Nr3c1. A side effect induced by GCs is increased production of reactive oxygen species. Available data show that the brain's response to GCs is part of an emergency mode characterized by inactivation of non-core activities, restrained inflammation, restriction of investments (growth), improved efficiency of energy production and the removal of unnecessary or malfunctioning cellular components to conserve energy and maintain nutrient supply during the stress response.

MiR-378 promotes the cell proliferation of osteosarcoma through down-regulating the expression of Kruppel-like factor 9

MicroRNAs (miRNAs) are small non-coding RNAs that play important roles in a variety of biological processes. Dysregulation of miRNAs is tightly associated with the malignancy of cancers. Aberrant expression of miR-378 has been observed in human cancers; however, the function of miR-378 in osteosarcoma (OS) remains largely unknown. Here, we showed that miR-378 was highly expressed in human OS tissues and cell lines. Overexpression of miR-378 significantly promoted the cell proliferation of OS cells. Molecular studies identified Kruppel-like factor-9 (KLF9) as a functional downstream target of miR-378. MiR-378 directly bound to the mRNA 3'-UTR region of KLF9 and suppressed the expression of KLF9. Highly expressed KLF9 reversed the promoting effect of miR-378 on the proliferation of OS cells. The expression level of miR-378 was negatively correlated with that of KLF9 in OS tissues. Collectively, our results demonstrated the molecular interaction between miR-378 and KLF9, indicating the therapeutic potential of miR-378 for OS.

Transcription factor KLF13 inhibits AKT activation and suppresses the growth of prostate carcinoma cells

BACKGROUND

Krüppel-like factor 13 (KLF13), a member of the KLF family, is involved in the development of immunological diseases and tumor progression. However, the expression patterns and potential functions of KLF13 in prostate carcinoma are still unknown. Here, we aimed to study the roles and mechanisms of KLF13 in prostate cancer.

METHODS

The expression levels of KLF13 was detected by Immunohistochemistry in prostate tumor tissues and the paired non-tumor tissues. The effects of KLF13 up-regulation was tested by performing CCK8, cell colon formation, flow cytometric analysis and measurement of tumor proliferation in nude mice. Signaling pathway was analyzed by Western blot.

RESULTS

The current study, for the first time, found that KLF13 was downregulated in prostate tumor tissues as compared to the paired non-tumor tissues. The overexpression of KLF13 dramatically inhibited cell proliferation and induced apoptosis by suppressing the AKT pathway in human prostate cancer cells. Moreover, the ectopic expression of KLF13 efficiently delayed the onset of PC3 xenografts and inhibited the tumor growth in vivo.

CONCLUSIONS

KLF13 functions as a tumor suppressor protein in PCa, and the pharmacological activation of KLF13 might represent a potential approach for the treatment of prostate cancer.

Aggressive rat prostate tumors reprogram the benign parts of the prostate and regional lymph nodes prior to metastasis

In order to grow and spread tumors need to interact with adjacent tissues. We therefore hypothesized that small but aggressive prostate cancers influence the rest of the prostate and regional lymph nodes differently than tumors that are more indolent. Poorly metastatic (Dunning AT1) or highly metastatic (Dunning MLL) rat prostate tumor cells were injected into the ventral prostate lobe of immunocompetent rats. After 10 days—when the tumors occupied about 30% of the prostate lobe and lymph node metastases were undetectable—the global gene expression in tumors, benign parts of the prostate, and regional iliac lymph nodes were examined to define tumor-induced changes related to preparation for future metastasis. The tumors induced profound effects on the gene expression profiles in the benign parts of the prostate and these were strikingly different in the two tumor models. Gene ontology enrichment analysis suggested that tumors with high metastatic capacity were more successful than less metastatic tumors in inducing tumor-promoting changes and suppressing anti-tumor immune responses in the entire prostate. Some of these differences such as altered angiogenesis, nerve density, accumulation of T-cells and macrophages were verified by immunohistochemistry. Gene expression alterations in the regional lymph nodes suggested decreased quantity and activation of immune cells in MLL-lymph nodes that were also verified by immunostaining. In summary, even when small highly metastatic prostate tumors can affect the entire tumor-bearing organ and pre-metastatic lymph nodes differently than less metastatic tumors. When the kinetics of these extratumoral influences (by us named TINT = tumor instructed normal tissue) are more precisely defined they could potentially be used as markers of disease aggressiveness and become therapeutic targets.

Exosomes from bulk and stem cells from human prostate cancer have a differential microRNA content that contributes cooperatively over local and pre-metastatic niche

The different prostate cancer (PCa) cell populations (bulk and cancer stem cells, CSCs) release exosomes that contain miRNAs that could modify the local or premetastatic niche. The analysis of the differential expression of miRNAs in exosomes allows evaluating the differential biological effect of both populations on the niche, and the identification of potential biomarkers and therapeutic targets. Five PCa primary cell cultures were established to originate bulk and CSCs cultures. From them, exosomes were purified by precipitation for miRNAs extraction to perform a comparative profile of miRNAs by next generation sequencing in an Illumina platform. 1839 miRNAs were identified in the exosomes. Of these 990 were known miRNAs, from which only 19 were significantly differentially expressed: 6 were overexpressed in CSCs and 13 in bulk cells exosomes. miR-100-5p and miR-21-5p were the most abundant miRNAs. Bioinformatics analysis indicated that differentially expressed miRNAs are highly related with PCa carcinogenesis, fibroblast proliferation, differentiation and migration, and angiogenesis. Besides, miRNAs from bulk cells affects osteoblast differentiation. Later, their effect was evaluated in normal prostate fibroblasts (WPMY-1) where transfection with miR-100-5p, miR-21-5p and miR-139-5p increased the expression of metalloproteinases (MMPs) -2, -9 and -13 and RANKL and fibroblast migration. The higher effect was achieved with miR21 transfection. As conclusion, miRNAs have a differential pattern between PCa bulk and CSCs exosomes that act collaboratively in PCa progression and metastasis. The most abundant miRNAs in PCa exosomes are interesting potential biomarkers and therapeutic targets.

Androgen receptor profiling predicts prostate cancer outcome

Prostate cancer is the second most prevalent malignancy in men. Biomarkers for outcome prediction are urgently needed, so that high-risk patients could be monitored more closely postoperatively. To identify prognostic markers and to determine causal players in prostate cancer progression, we assessed changes in chromatin state during tumor development and progression. Based on this, we assessed genomewide androgen receptor/chromatin binding and identified a distinct androgen receptor/chromatin binding profile between primary prostate cancers and tumors with an acquired resistance to therapy. These differential androgen receptor/chromatin interactions dictated expression of a distinct gene signature with strong prognostic potential. Further refinement of the signature provided us with a concise list of nine genes that hallmark prostate cancer outcome in multiple independent validation series. In this report, we identified a novel gene expression signature for prostate cancer outcome through generation of multilevel genomic data on chromatin accessibility and transcriptional regulation and integration with publically available transcriptomic and clinical datastreams. By combining existing technologies, we propose a novel pipeline for biomarker discovery that is easily implementable in other fields of oncology.

Long non-coding RNA TUG1 is up-regulated in hepatocellular carcinoma and promotes cell growth and apoptosis by epigenetically silencing of KLF2

Background

Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death worldwide, and the biology of this cancer remains poorly understood. Recent evidence indicates that long non-coding RNAs (lncRNAs) are found to be dysregulated in a variety of cancers, including HCC. Taurine Up-regulated Gene 1 (TUG1), a 7.1-kb lncRNA, recruiting and binding to polycomb repressive complex 2 (PRC2), is found to be disregulated in non-small cell lung carcinoma (NSCLC) and esophageal squamous cell carcinoma (ESCC). However, its clinical significance and potential role in HCC remain unclear.

Methods and results

In this study, expression of TUG1 was analyzed in 77 HCC tissues and matched normal tissues by using quantitative polymerase chain reaction (qPCR). TUG1 expression was up-regulated in HCC tissues and the higher expression of TUG1 was significantly correlated with tumor size and Barcelona Clinic Liver Cancer (BCLC) stage. Moreover, silencing of TUG1 expression inhibited HCC cell proliferation, colony formation, tumorigenicity and induced apoptosis in HCC cell lines. We also found that TUG1 overexpression was induced by nuclear transcription factor SP1 and TUG1 could epigeneticly repress Kruppel-like factor 2 (KLF2) transcription in HCC cells by binding with PRC2 and recruiting it to KLF2 promoter region.

Conclusion

Our results suggest that lncRNA TUG1, as a growth regulator, may serve as a new diagnostic biomarker and therapy target for HCC.

Electronic supplementary material

The online version of this article (doi:10.1186/s12943-015-0431-0) contains supplementary material, which is available to authorized users.

Mitochondrial thioredoxin reductase regulates major cytotoxicity pathways of proteasome inhibitors in multiple myeloma cells

It is generally accepted that intracellular oxidative stress induced by proteasome inhibitors is a byproduct of endoplasmic reticulum (ER) stress. Here we report a mechanism underlying the ability of proteasome inhibitors bortezomib (BTZ) and carfilzomib (CFZ) to directly induce oxidative and ER stresses in multiple myeloma (MM) cells via transcriptional repression of a gene encoding mitochondrial thioredoxin reductase (TXNRD2). TXNRD2 is critical for maintenance of intracellular red-ox status and detoxification of reactive oxygen species. Depletion of TXNRD2 to the levels detected in BTZ- or CFZ-treated cells causes oxidative stress, ER stress and death similar to those induced by proteasome inhibitors. Reciprocally, restoration of near-wildtype TXNRD2 amounts in MM cells treated with proteasome inhibitors reduces oxidative stress, ER stress and cell death by ~46%, ~35% and ~50%, respectively, compared with cells with unrestored TXNRD2 levels. Moreover, cells from three MM cell lines selected for resistance to BTZ demonstrate elevated levels of TXNRD2, indirectly confirming its functional role in BTZ resistance. Accordingly, ectopic expression of TXNRD2 in MM cell xenografts in immunocompromised mice blunts therapeutic effects of BTZ. Our data identify TXNRD2 as a potentially clinically relevant target, inhibition of which is critical for proteasome inhibitor-dependent cytotoxicity, oxidative stress and ER stress.

17-ABAG, a novel geldanamycin derivative, inhibits LNCaP-cell proliferation through heat shock protein 90 inhibition

Prostate cancer is one of the most common cancer types worldwide. In 2014, there were an estimated 233,000 new cases and 29,480 mortalities in the United States. Androgen deprivation therapy, also called androgen suppression therapy, targets androgen signaling and remains the standard treatment for patients with advanced prostate cancer; however, responses to treatment are not durable and most patients advance to castrate-resistant prostate cancer. Therefore, novel therapeutic strategies to treat prostate cancer are urgently required. Heat shock protein 90 (Hsp90) is a chaperone protein that has been shown to regulate the progression of tumor cells. Numerous Hsp90 inhibitors show anti-tumor activity and several of them have entered clinical trials. Geldanamycin (GA) was identified as the first Hsp90 inhibitor, but shows hepatotoxicity at its effective concentrations, limiting its clinical use. In previous studies by our group, the GA derivative 17-ABAG was designed and synthesized. The present study showed that 17-ABAG inhibits the proliferation and induces apoptosis of LNCaP, an androgen-dependent prostate cancer cell line, in vitro through a classic apoptotic pathway. 17-ABAG also downregulated the Hsp90 client protein and inhibited androgen receptor nuclear localization in LNCaP cells. In addition, 17-ABAG suppressed the growth of LNCaP xenograft tumors without any obvious side-effects. The present study demonstrated that 17-ABAG is a promising anti-tumor agent and warrants further validation in prospective studies.

The Krüppel-like factors in female reproductive system pathologies

Female reproductive tract pathologies arise largely from dysregulation of estrogen and progesterone receptor signaling, leading to aberrant cell proliferation, survival, and differentiation. The signaling pathways orchestrated by these nuclear receptors are complex, require the participation of many nuclear proteins serving as key binding partners or targets, and involve a range of paracrine and autocrine regulatory circuits. The members of the Krüppel-like factor (KLF) family of transcription factors are ubiquitously expressed in reproductive tissues and have been increasingly implicated as critical co-regulators and integrators of steroid hormone actions. Herein, we explore the involvement of KLF family members in uterine pathology, describe their currently known molecular mechanisms, and discuss their potential as targets for therapeutic intervention.

Long noncoding RNA ANRIL promotes non-small cell lung cancer cell proliferation and inhibits apoptosis by silencing KLF2 and P21 expression

Recent evidence highlights long noncoding RNAs (lncRNA) as crucial regulators of cancer biology that contribute to essential cancer cell functions such as cell proliferation, apoptosis, and metastasis. In non-small cell lung cancer (NSCLC), several lncRNAs' expressions are misregulated and have been nominated as critical actors in NSCLC tumorigenesis. LncRNA ANRIL was first found to be required for the PRC2 recruitment to and silencing of p15(INK4B), the expression of which is induced by the ATM-E2F1 signaling pathway. Our previous study showed that ANRIL was significantly upregulated in gastric cancer, and it could promote cell proliferation and inhibit cell apoptosis by silencing of miR99a and miR449a transcription. However, its clinical significance and potential role in NSCLC is still not documented. In this study, we reported that ANRIL expression was increased in NSCLC tissues, and its expression level was significantly correlated with tumor-node-metastasis stages and tumor size. Moreover, patients with high levels of ANRIL expression had a relatively poor prognosis. In addition, taking advantage of loss-of-function experiments in NSCLC cells, we found that knockdown of ANRIL expression could impair cell proliferation and induce cell apoptosis both in vitro and vivo. Furthermore, we uncover that ANRIL could not repress p15 expression in PC9 cells, but through silencing of KLF2 and P21 transcription. Thus, we conclusively demonstrate that lncRNA ANRIL plays a key role in NSCLC development by associating its expression with survival in patients with NSCLC, providing novel insights on the function of lncRNA-driven tumorigenesis.

Transcription factor KLF9 suppresses the growth of hepatocellular carcinoma cells in vivo and positively regulates p53 expression

Krüppel-like factor 9 (KLF9) is known to be a tumor suppressor gene in colorectal tumors and glioblastoma; however, the functional status and significance of KLF9 in hepatocellular carcinoma (HCC) is unclear. We report here that KLF9 is downregulated in HCC tissues. Restoration of KLF9 significantly inhibited growth and caused apoptosis in SK-Hep1 and HepG2 cells. We found that KLF9 positively regulated p53 levels by directly binding to GC boxes within the proximal region of the p53 promoter. Moreover, in the presence of cycloheximide, KLF9 significantly increased p53 stability in HCC cells. Remarkably, ectopic expression of KLF9 was sufficient to delay the onset of tumors and to promote regression of the established tumors in vivo, suggesting that KLF9 plays a critical role in HCC development and that pharmacological or genetic activation of KLF9 may have potential in the treatment of HCC.