Overexpression of SPAG9 correlates with poor prognosis and tumor progression in hepatocellular carcinoma

Cancer testis antigens: Emerging therapeutic targets leveraging genomic instability in cancer

Cancer care has witnessed remarkable progress in recent decades, with a wide array of targeted therapies and immune-based interventions being added to the traditional treatment options such as surgery, chemotherapy, and radiotherapy. However, despite these advancements, the challenge of achieving high tumor specificity while minimizing adverse side effects continues to dictate the benefit-risk balance of cancer therapy, guiding clinical decision making. As such, the targeting of cancer testis antigens (CTAs) offers exciting new opportunities for therapeutic intervention of cancer since they display highly tumor specific expression patterns, natural immunogenicity and play pivotal roles in various biological processes that are critical for tumor cellular fitness. In this review, we delve deeper into how CTAs contribute to the regulation and maintenance of genomic integrity in cancer, and how these mechanisms can be exploited to specifically target and eradicate tumor cells. We review the current clinical trials targeting aforementioned CTAs, highlight promising pre-clinical data and discuss current challenges and future perspectives for future development of CTA-based strategies that exploit tumor genomic instability.

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.

ZSCAN16-AS1 expedites hepatocellular carcinoma progression via modulating the miR-181c-5p/SPAG9 axis to activate the JNK pathway

Hepatocellular carcinoma (HCC) is generally known as one of the most common cancers in the world. Nowadays, interventional therapies such as transcatheter arterial chemoembolization (TACE) have emerged as an efficient therapy for HCC patients. Accumulating evidence has unveiled that long non-coding RNAs (lncRNAs) are crucial regulators in HCC progression. Nonetheless, the biological function of lncRNA zinc finger and SCAN domain containing 16 antisense RNA 1 (ZSCAN16-AS1) in HCC has not been systematically clarified. RT-qPCR was used to test ZSCAN16-AS1 expression in HCC cells. The biological functions of RP11-757 G1.5 on HCC cell proliferation, migration, invasion and apoptosis were investigated by colony formation, EdU, CCK-8 and transwell assays, as well as flow cytometry analysis. RNA immunoprecipitation (RIP), RNA pull-down and luciferase reporter assays were utilized to explore the specific mechanism of ZSCAN16-AS1. ZSCAN16-AS1 was significantly up-regulated in HCC cells. ZSCAN16-AS1 silence inhibited HCC cell proliferation, migration and invasion, while it accelerated HCC cell apoptosis. ZSCAN16-AS1 worked as a competing endogenous RNA (ceRNA) to regulate sperm associated antigen 9 (SPAG9) expression through sponging miR-181 c-5p. Moreover, SPAG9 could activate the c-Jun-N-terminal kinase (JNK) pathway. Taken together, our study elucidated that ZSCAN16-AS1 expedited HCC progression via modulating the miR-181 c-5p/SPAG9 axis to activate the JNK pathway, which might be a highly potential HCC therapy and treatment target.

A negative feedback loop between JNK-associated leucine zipper protein and TGF-β1 regulates kidney fibrosis

Renal fibrosis is controlled by profibrotic and antifibrotic forces. Exploring anti-fibrosis factors and mechanisms is an attractive strategy to prevent organ failure. Here we identified the JNK-associated leucine zipper protein (JLP) as a potential endogenous antifibrotic factor. JLP, predominantly expressed in renal tubular epithelial cells (TECs) in normal human or mouse kidneys, was downregulated in fibrotic kidneys. Jlp deficiency resulted in more severe renal fibrosis in unilateral ureteral obstruction (UUO) mice, while renal fibrosis resistance was observed in TECs-specific transgenic Jlp mice. JLP executes its protective role in renal fibrosis via negatively regulating TGF-β1 expression and autophagy, and the profibrotic effects of ECM production, epithelial-to-mesenchymal transition (EMT), apoptosis and cell cycle arrest in TECs. We further found that TGF-β1 and FGF-2 could negatively regulate the expression of JLP. Our study suggests that JLP plays a central role in renal fibrosis via its negative crosstalk with the profibrotic factor, TGF-β1.

Qi Yan et al. find that JNK-associated leucine zipper protein (Jlp) counteracts the profibrotic effects of TGF-β1 and autophagy on renal tubular epithelial cells and that TGF-β1 and FGF-2 can negatively regulate the expression of Jlp. These findings provide insights into the role of Jlp in kidney fibrosis.

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.

JLP-JNK signaling protects cancer cells from reactive oxygen species-induced cell death

Oxidative stress, which can be caused by an overproduction of reactive oxygen species (ROS), often leads to cell death. In recent years, c-Jun NH₂-terminal kinase (JNK)-associated leucine zipper protein (JLP, also known as SPAG9 or JIP4), a scaffold protein for JNK mitogen-activated protein kinase (MAPK) signaling pathways, was found to serve as a novel biomarker for cancer. However, although JNK MAPK pathways are reported to be activated in response to various stimuli, including oxidative stress, whether JLP is involved in ROS signaling remains unknown. In this study, we examined the role of JLP in hydrogen peroxide (H₂O₂)-induced cancer cell death, and found that JLP knockdown (KD) cells exhibit a substantially enhanced cell death response, along with increased intracellular ROS levels. This is the first demonstration of a protective role for JLP in response to cell-death stimulation. We also found that the H₂O₂-induced JNK activation was attenuated in JLP KD cancer cells. The decreases in cell viability and JNK activation in the JLP KD cells were almost completely reversed by expressing wild-type JLP, but not a mutant JLP lacking the JNK-binding domain. These data collectively suggest that the JLP-JNK signaling pathway counteracts ROS-induced cancer cell death.

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

Ovarian cancer is the most fatal gynecologic cancer with poor prognosis. Etiological factors underlying ovarian cancer genesis and progression are poorly understood. Previously, we have shown that JNK-associated Leucine zipper Protein (JLP), promotes oncogenic signaling. Investigating the role of JLP in ovarian cancer, our present study indicates that JLP is overexpressed in ovarian cancer tissue and ovarian cancer cells. Transient overexpression of JLP promotes proliferation and invasive migration of ovarian cancer cells. In addition, ectopic expression of JLP confers long-term survival and clonogenic potential to normal fallopian tube-derived epithelial cells. Coimmunoprecipitation and colocalization analyses demonstrate the in vivo interaction of JLP and JNK, which is stimulated by lysophosphatidic acid (LPA), an oncogenic lipid growth factor in ovarian cancer. We also show that LPA stimulates the translocation of JLP-JNK complex to the perinuclear region of SKOV3-ip cells. JLP-knockdown using shRNA abrogates LPA-stimulated activation of JNK as well as LPA-stimulated proliferation and invasive migration of SKOV3-ip cells. Studies using ovarian cancer xenograft mouse model indicate that the mice bearing JLP-silenced xenografts exhibits reduced tumor volume. Analysis of the xenograft tumor tissues indicate a reduction in the levels of JLP, JNK, phosphorylated-JNK, c-Jun and phosphorylated-c-Jun in JLP-silenced xenografts, thereby correlating the attenuated JLP-JNK signaling node with suppressed tumor growth. Thus, our results identify a critical role for JLP-signaling axis in ovarian cancer and provide evidence that targeting this signaling node could provide a new avenue for therapy.

AKAP4, SPAG9 and NY-ESO-1 in Iranian Colorectal Cancer Patients as Probable Diagnostic and Prognostic Biomarkers

Background and objectives:

Colorectal cancer (CRC) is the most common gastrointestinal cancer and the second leading cause of cancer death in women in the world. Cancer-Testis Antigens (CTAs) are a group of tumor-associated proteins which typically are expressed in normal reproductive cells of men, but their expression in normal somatic cells is silenced. CTAs, due to their limited expression pattern, are considered as promising targets for cancer diagnosis and immuno-therapy.

Methods:

Expression of AKAP4, SPAG9 and CTAG1B genes from the CTAs family was studied in both tumor and normal tissues of 62 Iranian CRC patients by RT-PCR with the aim of finding biomarkers for early detection and anticipated progression. Statistical analysis was performed SPSS software V22.0 to assess the significance of any associations.

Results:

Elevated expression of SPAG9 and AKAP4 genes was observed in approximately 66% and 44% of tumours, respectively, as compared to adjacent non-cancerous tissues. While a significant association was found between AKAP4 gene expression and metastasis (P-value: 0.045), expression of the CTAG1B (NY-ESO-1) gene was not observed in our cases.

Conclusion:

AKAP4 and SPAG9 genes may find use as diagnostic biomarkers for CRC and AKAP4 may play an important role in progression to metastasis.

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.

The expression of DAMP proteins HSP70 and cancer-testis antigen SPAG9 in peripheral blood of patients with HCC and lung cancer

There are different views of how the immune system participates in the reaction to cancer. Here, we evaluated expression of DAMP proteins HSP70 and cancer-testis antigen SPAG9 in patients with hepatocellular carcinoma (HCC) and lung cancer to explore tumor immunity. Our analysis showed that levels of HSP70 and SPAG9 antibody were significantly higher in the serum of lung cancer and HCC patients than in the serum of healthy subjects (P < 0.001), but there were no differences in levels of HSP70 antibody in patients and controls. Levels of serum SPAG9 antibody in newly diagnosed lung cancer patients were significantly higher than in treated lung cancer patients (P < 0.05), but there were no differences in levels of HSP70 or HSP70 antibody. Levels of serum HSP70 and SPAG9 antibody, but not HSP70 antibody, were also higher in hepatitis/cirrhosis patients than in healthy subjects (P = 0.005, P < 0.001). Levels of serum SPAG9 antibody were significantly higher in HCC patients than in hepatitis/cirrhosis patients, but there were no differences in HSP70 or HSP70 antibody levels. Finally, levels of serum HSP70 and SPAG9 antibody were significantly higher in HCC patients than in lung cancer patients (P < 0.05, P < 0.001). These results indicate that cancer-testis antigen SPAG9 induces a strong humoral immune response in cancer patients but HSP70 does not. These results show that SPAG9 has potential as a tumor-specific biomarker.

SPAG9 is overexpressed in osteosarcoma, and regulates cell proliferation and invasion through regulation of JunD

Sperm-associated antigen 9 (SPAG9) is a recently characterized oncoprotein that is considered to be involved in several forms of malignant tumor. However, its biological function and expression pattern in human osteosarcoma have not yet been elucidated. In the present study, SPAG9 expression was analyzed in 58 cases of human osteosarcoma by immunohistochemistry. The results demonstrated that SPAG9 was overexpressed in 63.8% (37/58) of osteosarcoma tissues, while normal bone tissues exhibited negative SPAG9 expression. SPAG9 small interfering RNA was employed in the U2OS cell line, which has high endogenous expression, and SPAG9 transfection was performed in the MG63 cell line, which has low endogenous expression. MTT and Matrigel invasion assays demonstrated that SPAG-9-knockdown significantly reduced U2OS cell invasion and proliferation, while SPAG9 transfection enhanced MG63 cell proliferation and invasion. Furthermore, it was observed that SPAG9 positively regulated cyclin D1, phosphorylated-c-Jun NH2-terminal kinase (JNK) and JunD expression. Treatment with the JNK inhibitor, SP600125, abolished the upregulatory effect of SPAG9 on JunD. Taken together, the present study identified SPAG9 as a critical oncoprotein involved in osteosarcoma proliferation and invasion, possibly functioning through JNK-JunD signaling.

Cancer testis antigen SPAG9 is a promising marker for the diagnosis and treatment of lung cancer

Cancer testis antigen sperm-associated antigen 9 (SPAG9) is highly expressed in many types of cancers. In the present study, to obtain a better understanding of the relevance of SPAG9 in cancer diagnosis and treatment, the expression of SPAG9 mRNA and protein in lung cancer specimens was evaluated by RT-PCR, western blotting and immunohistochemistry. ELISA was used to quantify the SPAG9 autoantibody in the peripheral blood of lung cancer patients. The results showed that the expression of SPAG9 mRNA and protein in the lung cancer tissues was significantly higher than that in the adjacent non-cancerous tissues (P<0.01). The level of the SPAG9 autoantibody in the serum of lung cancer patients was significantly higher than the level in the healthy controls (P<0.001), and the level of the SPAG9 autoantibody in the serum of untreated patients was significantly higher than that in treated patients (P=0.002). SPAG9 IgG antibody levels were significantly lower in treated adenocarcinoma and small cell lung cancer patients than these levels in the untreated patients (P=0.006, P=0.026, respectively), while no statistical difference was found between treated and untreated squamous cell carcinoma patients. Our results suggest that the SPAG9 antibody in serum is a promising marker for the diagnosis of lung cancer, and the level of the humoral immune response to this antigen appears to be related to the type of lung cancer.

Direct targeting sperm-associated antigen 9 by miR-141 influences hepatocellular carcinoma cell growth and metastasis via JNK pathway

BACKGROUND

The aberrant expression of sperm-associated antigen 9 (SPAG9) is associated with numerous cancers, including hepatocellular carcinoma (HCC). The exploration of molecules and mechanisms regulating SPAG9 expression may provide new options for HCC therapy.

METHODS

MiRNA target prediction programs were used to explore SPAG9-targeted miRNAs. SPAG9 and miR-141 expression were detected in HCC tissues and cell lines by Western blot and real-time PCR. Dual-luciferase reporter assay was utilized to validate SPAG9 as a direct target gene of miR-141. Cell proliferation, invasion, and migration assays were used to determine whether miR-141-mediated regulation of SPAG9 could affect HCC progression.

RESULTS

An inverse correlation was observed between SPAG9 and miR-141 expression in HCC tissues and cell lines. Dual-luciferase reporter assay further showed that SPAG9 was a direct target gene of miR-141. The ectopic expression of miR-141 could markedly suppress SPAG9 expression in HCC cells. MiR-141 overexpression also resulted in significantly reduced cell proliferation, invasion, and migration, and imitation of the SPAG9 knockdown effects on HCC cells. Furthermore, SPAG9 restoration in miR-141-expressing cells sufficiently attenuated the tumor-suppressive effects of miR-141. Finally, JNK activity was found to be reduced by miR-141 overexpression the same way as by SPAG9 silencing. The overexpression of SPAG9 lacking its 3'-UTR significantly restored JNK activity and its downstream genes in miR-141-transfected HCC cells.

CONCLUSION

MiR-141 suppression may cause aberrant expression of SPAG9 and promote HCC tumorigenesis via JNK pathway.

Targeting cancer testis antigens for biomarkers and immunotherapy in colorectal cancer: Current status and challenges

Colorectal cancer ranks third among the estimated cancer cases and cancer related mortalities in United States in 2014. Early detection and efficient therapy remains a significant clinical challenge for this disease. Therefore, there is a need to identify novel tumor associated molecules to target for biomarker development and immunotherapy. In this regard, cancer testis antigens have emerged as a potential targets for developing novel clinical biomarkers and immunotherapy for various malignancies. These germ cell specific proteins exhibit aberrant expression in cancer cells and contribute in tumorigenesis. Owing to their unique expression profile and immunogenicity in cancer patients, cancer testis antigens are clinically referred as the most promising tumor associated antigens. Several cancer testis antigens have been studied in colorectal cancer but none of them could be used in clinical practice. This review is an attempt to address the promising cancer testis antigens in colorectal cancer and their possible clinical implications as biomarkers and immunotherapeutic targets with particular focus on challenges and future interventions.

Sperm-associated antigen 9 overexpression correlates with poor prognosis and insensitive to Taxol treatment in breast cancer

Sperm-associated antigen 9 (SPAG9) has been reported to express in several cancers and have clinical significance. Using immunohistochemistry, we found that there was a strong association among SPAG9 expression and tumor size, TNM stage, histological grade, lymph node metastasis, and recurrence. It suggested that SPAG9-elevated expression was an independently prognostic indicator for both OS and DFS. Furthermore, the selected treatment of chemotherapy with Taxol/non-Taxol significantly affects OS and DFS. To sum up, SPAG9-elevated expression contributes to malignant behavior and poor prognosis of breast cancer and may support a potential indicator in treatment selection.

Overexpression of SPAG9 in human gastric cancer is correlated with poor prognosis

Sperm associated antigen 9 (SPAG9) protein has been found to play an important role in cancer progression but the involved mechanisms are still obscure. Its clinical significance in human gastric cancers remains unexplored. In the present study, SPAG9 expression was analyzed in 147 gastric cancer specimens. We observed weak staining in normal gastric mucosa and positive staining in 65 out of 147 (44.2 %) cancer samples. Overexpression of SPAG9 correlated with local invasion (p = 0.0101), lymph node metastasis (p = 0.0488), TNM stage (p = 0.0002), and relapse (p = 0.0018). Importantly, SPAG9 overexpression correlated with poor overall survival (p = 0.0008). Furthermore, we performed siRNA knockdown of SPAG9 in HGC-27 cells with high endogenous expression and transfected SPAG9 plasmid in SGC-7901 cell line with low endogenous level. SPAG9 overexpression promoted while its depletion inhibited cell proliferation, cell cycle transition, and invasive cell growth. SPAG9 overxpression also increased chemoresistance to 5--fluorouracil (5-FU) in SGC-7901 cells. Further analysis showed that SPAG9 knockdown downregulated and its overexpression upregulated cyclin D1, MMP9, and p-p38 expression. In conclusion, SPAG9 overexpression in gastric cancer correlates with poor prognosis and contributes to gastric cancer cell proliferation, invasion, and chemoresistance. SPAG9 promotes gastric cancer invasion, possibly through p38-MMP9 signaling pathways.

Targeted sequencing in chromosome 17q linkage region identifies familial glioma candidates in the Gliogene Consortium

Glioma is a rare, but highly fatal, cancer that accounts for the majority of malignant primary brain tumors. Inherited predisposition to glioma has been consistently observed within non-syndromic families. Our previous studies, which involved non-parametric and parametric linkage analyses, both yielded significant linkage peaks on chromosome 17q. Here, we use data from next generation and Sanger sequencing to identify familial glioma candidate genes and variants on chromosome 17q for further investigation. We applied a filtering schema to narrow the original list of 4830 annotated variants down to 21 very rare (<0.1% frequency), non-synonymous variants. Our findings implicate the MYO19 and KIF18B genes and rare variants in SPAG9 and RUNDC1 as candidates worthy of further investigation. Burden testing and functional studies are planned.

Sperm associated antigen 9 (SPAG9) expression and humoral response in benign and malignant salivary gland tumors

Salivary gland cancers are highly aggressive epithelial tumor associated with metastatic potential and high mortality. The tumors are biologically diverse and are of various histotypes. Besides, the detection and diagnosis is a major problem of salivary gland cancer for available treatment modalities. In the present study, we have investigated the association of sperm associated antigen 9 (SPAG9) expression with salivary gland tumor (SGT). Clinical specimens of benign (n = 16) and malignant tumors (n = 86) were examined for the SPAG9 expression. In addition, the sera and adjacent non-cancerous tissues (n = 72) from available patients were obtained. Our in situ RNA hybridization and immunohistochemistry (IHC) analysis revealed significant difference (p = 0.0001) in SPAG9 gene and protein expression in benign (63%) and malignant tumor (84%) specimens. Further, significant association was also observed between SPAG9 expression and malignant tumors (P = 0.05). A cut-off value of >10% cells expressing SPAG9 protein designated as positive in IHC, predicted presence of malignant SGT with 83.72% sensitivity, 100% specificity, 100% PPV and 83.72% NPV. Humoral response against SPAG9 protein was generated in 68% of SGT patients. A cut-off value of 0.212 OD for anti-SPAG9 antibodies in ELISA predicted presence of malignant SGT with 69.23% sensitivity, 100% specificity, 100% PPV and 78.94% NPV. Collectively, our data suggests that the majority of SGT show significant difference and association among benign and malignant tumors for SPAG9 gene and protein expression and also exhibit humoral response against SPAG9 protein. Hence, SPAG9 may be developed as a biomarker for detection and diagnosis of salivary gland tumors.