Aberrant expression of JNK-associated leucine-zipper protein, JLP, promotes accelerated growth of ovarian cancer

SPAG9 Expression Predicts Good Prognosis in Patients with Clear-Cell Renal Cell Carcinoma: A Bioinformatics Analysis with Experimental Validation

Clear-cell renal cell carcinoma (ccRCC) is the most common and aggressive type of renal-cell carcinoma (RCC). Sperm-associated antigen 9 (SPAG9) has been reported to promote the progression of a variety of tumors and is thus a potential prognostic marker. This study combined a bioinformatics analysis with an experimental validation, exploring the prognostic value of SPAG9 expression in ccRCC patients and the possible underlying mechanisms. The SPAG9 expression was associated with a poor prognosis in pan-cancer patients, but with a good prognosis and slow tumor progression in ccRCC patients. To explore the underlying mechanism, we investigated the roles of SPAG9 in ccRCC and bladder urothelial carcinoma (BLCA). The latter was chosen for comparison with ccRCC to represent the tumor types in which SPAG9 expression suggests a poor prognosis. The overexpression of SPAG9 increased the expression of autophagy-related genes in 786-O cells but not in HTB-9 cells, and SPAG9 expression was significantly correlated with a weaker inflammatory response in ccRCC but not in BLCA. Through an integrated bioinformatics analysis, we screened out seven key genes (AKT3, MAPK8, PIK3CA, PIK3R3, SOS1, SOS2, and STAT5B) in this study. The correlation between SPAG9 expression and ccRCC prognosis depends on the expression of key genes. Since most of the key genes were PI3K-AKT-pathway members, we used the PI3K agonist 740Y-P to stimulate the 786-O cells, to mimic the effect of key-gene overexpression. Compared with the Ov-SPAG9 786-O cells, the 740Y-P further increased the expression of autophagy-related genes by more than twofold. Moreover, we constructed a nomogram based on SPAG9/key genes and other clinical features, which was proven to have some predictive value. Our study found that SPAG9 expression predicted opposite clinical outcomes in pan-cancer and ccRCC patients, and we speculated that SPAG9 suppresses tumor progression by promoting autophagy and inhibiting inflammatory responses in ccRCC. We further found that some genes might cooperate with SPAG9 to promote autophagy, and that these were highly expressed in the tumor stroma and could be represented by key genes. The SPAG9-based nomogram can help to estimate the long-term prognosis of ccRCC patients, indicating that SPAG9 is a potential prognostic marker for ccRCC.

Loss of JNK-Associated Leucine Zipper Protein Promotes Peritoneal Dialysis-Related Peritoneal Fibrosis

BACKGROUND

Peritoneal dialysis-related peritoneal fibrosis is the leading cause of peritoneal ultrafiltration failure. Multitude factors and pathological processes have been implicated in peritoneal fibrosis development and progression, whereas the intrinsic anti-fibrotic mechanism has rarely been explored. JNK-associated leucine zipper protein (JLP) has been recently found possessing powerful anti-fibrotic merits of overall antagonizing TGF-β-induced profibrotic effects.

OBJECTIVES

We wondered whether JLP is expressed in the peritoneum, and if so, whether it exerts the anti-fibrotic effects similar to those in the kidney.

METHOD

Here, we examined and confirmed JLP expression in peritoneum tissue of mice. Then, we established a peritoneal fibrosis model in Jlp wild-type and Jlp global deficient mice and observed the different effects of Jlp on peritoneal fibrosis progression. In vitro studies were performed on peritoneal mesothelial HMrSV5 cells with or without Jlp knockdown to investigate the underlying mechanism by which Jlp exerts anti-fibrotic effects.

RESULTS

We found that the expression of JLP decreased in a high-glucose peritoneal dialysis solution (HGPDS)-induced peritoneal fibrosis mouse model and in HGPDS-treated peritoneal mesothelial cell HMrSV5. JLP deletion exacerbated HGPDS-induced peritoneal fibrosis in peritoneal fibrosis mice, and knockdown of JLP resulted in an increased profibrotic response to HGPDS stimulation in HMrSV5 cells, which was associated with epithelial-to-mesenchymal transition, elevated autophagy, and apoptosis, as well as enhanced TGF-β1/Smad signaling activation.

CONCLUSIONS

Our findings revealed a new anti-fibrotic factor of Jlp involved in peritoneal fibrosis induction and shed light on novel therapeutic targets in peritoneal ultrafiltration failure.

Differential effects of thymoquinone on lysophosphatidic acid-induced oncogenic pathways in ovarian cancer cells

Thymoquinone, a therapeutic phytochemical derived from Nigella sativa, has been shown to have a potent anticancer activity. However, it has been identified that the tumor microenvironment (TME) can attenuate the anticancer effects of thymoquinone (TQ) in ovarian cancer. Lysophosphatidic acid (LPA), a lipid growth factor present in high concentration in the TME of ovarian cancer, has been shown to regulate multiple oncogenic pathways in ovarian cancer. Taking account of the crucial role of LPA in the genesis and progression of ovarian cancer, the present study is focused on assessing the efficacy of TQ in inhibiting LPA-stimulated oncogenic pathways in ovarian cancer cells. Our results indicate that TQ is unable to attenuate LPA-stimulated proliferation or metabolic reprogramming in ovarian cancer cells. However, TQ potently inhibits the basal as well as LPA-stimulated migratory responses of the ovarian cancer cells. Furthermore, TQ abrogates the invasive migration of ovarian cancer cells induced by Gαi2, through which LPA stimulates cell migration. TQ also attenuates the activation of JNK, Src, and FAK, the downstream signaling nodes of LPA-LPAR-Gαi2 signaling pathway. In addition to establishing the differential effects of TQ in ovarian cancer cells, our results unravel the antitherapeutic role of LPA in the ovarian cancer TME could override the inhibitory effects of TQ on cell proliferation and metabolic reprogramming of ovarian cancer cells. More importantly, the concomitant finding that TQ could still sustain its inhibitory effect on LPA-stimulated invasive cell migration, points to its potential use as a response-specific therapeutic agent in ovarian cancer.

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LPA, present in the TME of ovarian cancer, plays a determinant role in limiting the anti-oncogenic efficacy of TQ.

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TQ has no inhibitory effect on LPA-stimulated oncogenic cell proliferation and metabolic reprogramming.

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However, TQ potently inhibits both the basal and LPA- or the downstream Gαi2-induced invasive migration ovarian cancer cells.

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Corollary to these findings, TQ also inhibits JNK, Src, and FAK that are involved in LPA-induced invasive cell migration.

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These findings identify the potential of TQ as a response-specific therapeutic phytochemical in vivo.

SHARPIN overexpression promotes TAK1 expression and activates JNKs and NF-κB pathway in Mycosis Fungoides

Mycosis Fungoides (MF) is the most common subtype of cutaneous T-cell lymphomas (CTCL). Shank-associated RH domain-interacting protein (SHARPIN) participates in the initiation and development of multiple tumors. However, the clinical significance of SHARPIN in MF hasn't been investigated. The c-Jun N-terminal kinases (JNKs) pathway is a member of mitogen-activated protein kinases (MAPKs). Its dysregulation is observed in various tumors including CTCL, whereas the roles of JNKs pathway in MF remain largely unknown, the relationship between SHARPIN and JNKs pathway remains elusive. Herein, we showed that upregulated expression of SHARPIN was related to poor prognosis of MF patients. In vitro experiments found increased SHARPIN expression and activation of JNKs pathway in MF cell line MyLa2059. SHARPIN induced transforming growth factor β activated kinase-1 (TAK1) transcription, which is an upstream kinase of JNKs, NF-κB and p38 pathway, leading to activation of JNKs and NF-κB pathway. SHARPIN also promoted p38 signalling independent of TAK1 expression, by which overexpression of SHARPIN induced cell proliferation, inhibited apoptosis, enhanced migration and invasion of MyLa2059. Our work provided direct evidences for effects of SHARPIN on JNKs and NF-κB pathway, and the contributing roles of JNKs, NF-κB and p38 pathway regulated by SHARPIN in the development of MF.

JLP-centrosome is essential for the microtubule-mediated nucleocytoplasmic transport induced by extracellular stimuli

JLP belongs to the JIP family whose members serve as scaffolding proteins that link motor proteins and their cargo for intracellular transport. Although JLP is mainly cytoplasmic, it accumulates as a focus in the perinuclear region when stimulated by extracellular stimuli. Focus formation, which changes the nucleus shape and concentrates the nuclear pores, depends on p38MAPK activation and the dynein retrograde motor protein complex. Extracellular stimuli trigger the tethering of PLK1 to the centrosome by JLP, leading to centrosome maturation and microtubule array formation. The centrosome localization domain of JLP is important for the binding of the centrosome and the formation of the JLP focus and the microtubule array. Furthermore, the formation of the JLP focus and the microtubule array is interdependent and important for the transport of NF-κB p65 to the nucleus and its unloading therein. In conclusion, JLP exhibits multiple functions in the nuclear translocation of NF-κB p65.

Cancer-testis antigens in ovarian cancer: implication for biomarkers and therapeutic targets

Ovarian cancer remains the most fatal gynecologic malignancy worldwide due to delayed diagnosis as well as recurrence and drug resistance. Thus, the development of new tumor-related molecules with high sensitivity and specificity to replace or supplement existing tools is urgently needed. Cancer-testis antigens (CTAs) are exclusively expressed in normal testis tissues but abundantly found in several types of cancers, including ovarian cancer. Numerous novel CTAs have been identified by high-throughput sequencing techniques, and some aberrantly expressed CTAs are associated with ovarian cancer initiation, clinical outcomes and chemotherapy resistance. More importantly, CTAs are immunogenic and may be novel targets for antigen-specific immunotherapy in ovarian cancer. In this review, we attempt to characterize the expression of candidate CTAs in ovarian cancer and their clinical significance as biomarkers, activation mechanisms, function in malignant phenotypes and applications in immunotherapy.

Sperm-associated antigen 9 is upregulated in hepatocellular carcinoma tissue and enhances QGY cell proliferation and invasion in vitro

The incidence and mortality rates of hepatocellular carcinoma (HCC) are higher in China compared with in other countries. Further research is required in order to improve the diagnosis and treatment of HCC. Sperm-associated antigen 9 (SPAG9) protein has been revealed to serve an important function in cancer progression; however, the underlying mechanisms remain to be elucidated. The present study investigated the expression level of SPAG9 in HCC tissues using quantitative-polymerase chain reaction, immunohistochemistry and western blotting, and the results demonstrated that SPAG9 was overexpressed in HCC tissues compared with the adjacent non-cancerous tissues. To explore the potential mechanisms underlying SPAG9 in HCC, the effect of SPAG9 on cell proliferation, cell cycle, migration and invasion capacities were investigated in the QGY HCC cell line by RNA interference. It was revealed that inhibition of SPAG9 mRNA in QGY cells significantly inhibited the expression level of SPAG9 compared with the control. Depletion of SPAG9 expression decreased cell proliferation (P<0.01) and increased the percentage of cells in the G₁/G₂ cell cycle phase. The percentage of cells in the S phase was decreased, and cell migration and invasion capabilities in vitro were reduced (P<0.01). In summary, the results of the present study suggested that SPAG9 was upregulated in HCC and may serve an important function in cancer cell proliferation, differentiation and invasion. Whether SPAG9 is a potential diagnostic marker and therapeutic target of human HCC requires additional study.

LPA Induces Metabolic Reprogramming in Ovarian Cancer via a Pseudohypoxic Response

Although hypoxia has been shown to reprogram cancer cells toward glycolytic shift, the identity of extrinsic stimuli that induce metabolic reprogramming independent of hypoxia, especially in ovarian cancer, is largely unknown. In this study, we use patient-derived ovarian cancer cells and high-grade serous ovarian cancer cell lines to demonstrate that lysophosphatidic acid (LPA), a lipid growth factor and GPCR ligand whose levels are substantially increased in ovarian cancer patients, triggers glycolytic shift in ovarian cancer cells. Inhibition of the G protein α-subunit Gαi2 disrupted LPA-stimulated aerobic glycolysis. LPA stimulated a pseudohypoxic response via Rac-mediated activation of NADPH oxidase and generation of reactive oxygen species, resulting in activation of HIF1α. HIF1α in turn induced expression of glucose transporter-1 and the glycolytic enzyme hexokinase-2 (HKII). Treatment of mice bearing ovarian cancer xenografts with an HKII inhibitor, 3-bromopyruvate, attenuated tumor growth and conferred a concomitant survival advantage. These studies reveal a critical role for LPA in metabolic reprogramming of ovarian cancer cells and identify this node as a promising therapeutic target in ovarian cancer.Significance: These findings establish LPA as a potential therapeutic target in ovarian cancer, revealing its role in the activation of HIF1α-mediated metabolic reprogramming in this disease. Cancer Res; 78(8); 1923-34. ©2018 AACR.

Next generation of network medicine: interdisciplinary signaling approaches

In the last decade, network approaches have transformed our understanding of biological systems. Network analyses and visualizations have allowed us to identify essential molecules and modules in biological systems, and improved our understanding of how changes in cellular processes can lead to complex diseases, such as cancer, infectious and neurodegenerative diseases. "Network medicine" involves unbiased large-scale network-based analyses of diverse data describing interactions between genes, diseases, phenotypes, drug targets, drug transport, drug side-effects, disease trajectories and more. In terms of drug discovery, network medicine exploits our understanding of the network connectivity and signaling system dynamics to help identify optimal, often novel, drug targets. Contrary to initial expectations, however, network approaches have not yet delivered a revolution in molecular medicine. In this review, we propose that a key reason for the limited impact, so far, of network medicine is a lack of quantitative multi-disciplinary studies involving scientists from different backgrounds. To support this argument, we present existing approaches from structural biology, 'omics' technologies (e.g., genomics, proteomics, lipidomics) and computational modeling that point towards how multi-disciplinary efforts allow for important new insights. We also highlight some breakthrough studies as examples of the potential of these approaches, and suggest ways to make greater use of the power of interdisciplinarity. This review reflects discussions held at an interdisciplinary signaling workshop which facilitated knowledge exchange from experts from several different fields, including in silico modelers, computational biologists, biochemists, geneticists, molecular and cell biologists as well as cancer biologists and pharmacologists.

Role of JNK signaling in oral cancer: A mini review

JNKs (c-Jun N-terminal kinases) belong to mitogen-activated protein kinases' family and become activated by several growth factors, stress, radiation, and other extracellular signals. In turn, JNK activation results in phosphorylation of downstream molecules involved in many normal cellular processes. Nevertheless, recent data have linked JNK signaling with several pathological conditions, including neurodegenerative diseases, inflammation, and cancer. The role of JNK in cancer remains controversial. Initially, JNK was thought to play a rather oncosuppressive role by mediating apoptosis in response to stress stimuli, inflammatory, or oncogenic signals. However, a number of studies have implicated JNK in malignant transformation and tumor growth. The contradictory functions of JNK in cancer may be due to the diversity of JNK upstream and downstream signaling and are under intensive investigation. This review summarizes current literature focusing on the significance of JNK pathway in cancer development and progression, particularly addressing its role in oral cancer. Understanding the complexity of JNK signaling has the potential to elucidate important molecular aspects of oral cancer, possibly leading to development of novel and individualized therapeutic strategies.