Gankyrin is a predictive and oncogenic factor in well-differentiated and dedifferentiated liposarcoma

Structural modification of the propyl linker of cjoc42 in combination with sulfonate ester and triazole replacements for enhanced gankyrin binding and anti-proliferative activity

Liver cancer is a complex disease that involves various oncoproteins and the inactivation of tumor suppressor proteins (TSPs). Gankyrin is one such oncoprotein, first identified in human hepatocellular carcinoma, that is known to inactivate multiple TSPs, leading to proliferation and metastasis of tumor cells. Despite this, there has been limited development of small molecule gankyrin binders for the treatment of liver cancer. In this study, we are reporting the structure-based design of gankyrin-binding small molecules which inhibit the proliferation of HuH6 and HepG2 cells while also increasing the levels of certain TSPs, such as Rb and p53. Interestingly the first molecule to exhibit inhibition by 3D structure stabilization is seen. These results suggest a possible mechanism for small-molecule inhibition of gankyrin and demonstrate that gankyrin is a viable therapeutic target for the treatment of liver cancer.

Helicobacter pylori and Epstein-Barr Virus Coinfection Stimulates Aggressiveness in Gastric Cancer through the Regulation of Gankyrin

Persistent coinfection with Helicobacter pylori and Epstein-Barr virus (EBV) promotes aggressive gastric carcinoma (GC). The molecular mechanisms underlying the aggressiveness in H. pylori and EBV-mediated GC are not well characterized. We investigated the molecular mechanism involved in H. pylori- and EBV-driven proliferation of gastric epithelial cells. Results showed that the coinfection is significantly more advantageous to the pathogens as coinfection creates a microenvironment favorable to higher pathogen-associated gene expression. The EBV latent genes ebna1 and ebna3c are highly expressed in the coinfection compared to lone EBV infection at 12 and 24 h. The H. pylori-associated genes 16S rRNA, cagA, and babA were also highly expressed during coinfection compared to H. pylori alone. In addition, upregulation of gankyrin, which is a small oncoprotein, modulates various cell signaling pathways, leading to oncogenesis. Notably, the knockdown of gankyrin decreased the cancer properties of gastric epithelial cells. Gankyrin showed a similar expression pattern as that of ebna3c at both transcript and protein levels, suggesting a possible correlation. Further, EBV and H. pylori created a microenvironment that induced cell transformation and oncogenesis through dysregulation of the cell cycle regulatory (ccnd1, dapk3, pcna, and akt), GC marker (abl1, tff-2, and cdx2), cell migration (mmp3 and mmp7), DNA response (pRB, pten, and p53), and antiapoptotic (bcl2) genes in infected gastric epithelial cells through gankyrin. Our study provides a new insight into the interplay of two oncogenic agents (H. pylori and EBV) that leads to an enhanced carcinogenic activity in gastric epithelial cells through overexpression of gankyrin. IMPORTANCE In the present study, we evaluated the synergistic effects of EBV and H. pylori infection on gastric epithelial cells in various coinfection models. These coinfection models were among the first to depict the exposures of gastric epithelial cells to EBV followed by H. pylori; however, coinfection models exist that narrated the scenario upon exposure to H. pylori followed by that to EBV. We determined that a coinfection by EBV and H. pylori enhanced the expression of oncogenic protein gankyrin. The interplay between EBV and H. pylori promoted the oncogenic properties of AGS cells like elevated focus formation, cell migration, and cell proliferation through gankyrin. EBV and H. pylori mediated an enhanced expression of gankyrin, which further dysregulated cancer-associated genes such as cell migratory, tumor suppressor, DNA damage response, and proapoptotic genes.

An Allosteric Interaction Network Promotes Conformation State-Dependent Eviction of the Nas6 Assembly Chaperone from Nascent 26S Proteasomes

The 26S proteasome is the central ATP-dependent protease in eukaryotes and is essential for organismal health. Proteasome assembly is mediated by several dedicated, evolutionarily conserved chaperone proteins. These chaperones associate transiently with assembly intermediates but are absent from mature proteasomes. Chaperone eviction upon completion of proteasome assembly is necessary for normal proteasome function, but how they are released remains unresolved. Here, we demonstrate that the Nas6 assembly chaperone, homolog of the human oncogene gankyrin, is evicted from nascent proteasomes during completion of assembly via a conformation-specific allosteric interaction of the Rpn5 subunit with the proteasomal ATPase ring. Subsequent ATP binding by the ATPase subunit Rpt3 promotes conformational remodeling of the ATPase ring that evicts Nas6 from the nascent proteasome. Our study demonstrates how assembly-coupled allosteric signals promote chaperone eviction and provides a framework for understanding the eviction of other chaperones from this bio-medically important molecular machine.

Nemec et al. report how the evolutionarily conserved Nas6 assembly chaperone is evicted from nascent 26S proteasomes. Nucleotide binding events within the nascent proteasome trigger formation of conformation-specific intersubunit contacts that expel Nas6. This mechanism may serve a quality control function by blocking formation of 26S proteasomes from defective components.

Precision Oncology in Sarcomas: Divide and Conquer

Sarcomas are a heterogeneous group of rare malignancies that exhibit remarkable heterogeneity, with more than 50 subtypes recognized. Advances in next-generation sequencing technology have resulted in the discovery of genetic events in these mesenchymal tumors, which in addition to enhancing understanding of the biology, have opened up avenues for molecularly targeted therapy and immunotherapy. This review focuses on how incorporation of next-generation sequencing has affected drug development in sarcomas and strategies for optimizing precision oncology for these rare cancers. In a significant percentage of soft tissue sarcomas, which represent up to 40% of all sarcomas, specific driver molecular abnormalities have been identified. The challenge to evaluate these mutations across rare cancer subtypes requires the careful characterization of these genetic alterations to further define compelling drivers with therapeutic implications. Novel models of clinical trial design also are needed. This shift would entail sustained efforts by the sarcoma community to move from one-size-fits-all trials, in which all sarcomas are treated similarly, to divide-and-conquer subtype-specific strategies.

Establishment of a Novel PDX Mouse Model and Evaluation of the Tumor Suppression Efficacy of Bortezomib Against Liposarcoma

The patient-derived xenograft (PDX) model has been adopted as a major tool for studying tumorigenesis and differentiation in various carcinomas. In addition, it has been used in the development of anticancer agents. PDX models have been among the most meaningful tools used to understand the role of stromal cells and vascular cells in the body, which are major factors in cancer development and the application of therapeutic agents. Also, the establishment of PDX models from liposarcoma patients is considered to be important for understanding lipomagenesis and following drugs development. For these reasons, we developed patient-derived cell (PDC) and PDX models derived from 20 liposarcoma patients. The tissues of these patients were obtained in accordance with the principles of the Samsung Medical Center's ethics policy, and cell culture and xenografting onto the mice were performed under these principles. High-throughput drug screening (HTS) was carried out using established PDCs to select candidate drugs. Among the different candidate anticancer drugs, we tested the effect of bortezomib, which was expected to inhibit MDM2 amplification. First, we confirmed that the PDCs maintained the characteristics of liposarcoma cells by assessing MDM2 amplification and CDK4 overexpression using fluorescence in situ hybridization. Analysis of short tandem repeats and an array using comparative genomic hybridization confirmed that the PDX model exhibited the same genomic profile as that of the patient. Immunohistochemistry for MDM2 and CDK4 showed that the overexpression patterns of both proteins were similar in the PDX models and the PDCs. Specifically, MDM2 amplification was observed to be significantly correlated with the successful establishment of PDX mouse models. However, CDK4 expression did not show such a correlation. Of the anticancer drugs selected through HTS, bortezomib showed a strong anticancer effect against PDC. In addition, we observed that bortezomib suppressed MDM2 expression in a dose-dependent manner. In contrast, p21 tended to elicit an increase in PDC expression. Treatment of the PDX model with bortezomib resulted in an anticancer effect similar to that seen in the PDCs. These results support that PDCs and PDX models are among the most powerful tools for the development and clinical application of anticancer drugs for the treatment of liposarcoma patients.

Gankyrin Drives Malignant Transformation of Gastric Cancer and Alleviates Oxidative Stress via mTORC1 Activation

Gastric cancer, as a malignant epithelial tumor, is a major health threat leading to poor overall survival and death. It is usually diagnosed at an advanced stage due to asymptomatic or only nonspecific early symptoms. The present study demonstrated that gankyrin contributes to the early malignant transformation of gastric cancer and can be selected to predict the risk of gastric cancer in those patients harboring the precancerous lesions (dysplasia and intestinal metaplasia). In addition, a new insight into gastric cancer was provided, which stated that gankyrin alleviates oxidative stress via mTORC1 pathway activation. It can potentiate the mTORC1 by PGK1-AKT signaling that promotes the tumor process, and this phenomenon is not completely consistent with the previous report describing colorectal cancer.

Gankyrin as a potential target for tumor therapy: evidence and perspectives

Gankyrin (also known as PSMD10 or p28GANK), engages in diverse biological processes, including cellular growth, proliferation and invasion. Several studies have demonstrated that Gankyrin is a candidate oncogene. In parallel, the dysregulation of Gankyrin has been observered in a variety of human cancer. Overexpression of Gankyrin is involved in tumor initiation and progression by regulating several signaling pathways that control cell-cycle process, cell growth, apoptosis, et al. On the contrary, downregulation of Gankyrin significantly inhibits cell growth, proliferation and metastasis. Therefore, Gankyrin appears to be a potential target for tumor therapy. Herein, this review summarizes the current knowledge in understanding the biological functions and oncogenic role of Gankyrin in human cancers from the perspective of clinical-pathological significances, aiming to provide guidance for the development of Gankyrin-targeted therapy.

The expression of the cancer testis antigen MAGE A4: A favorable prognostic biomarker in salivary gland carcinomas related to low tumor grading

Background

Aim was to analyze the expression of different cancer testis antigens (CTA) and to assess its prognostic value in salivary gland carcinomas.

Methods

Patients with salivary gland carcinomas diagnosed 1994 to 2010 were included. Baseline characteristics, pathohistological, clinical, and outcome data were assessed. Tissue microarrays were constructed and immunohistochemistry for different CTA (NY-ESO1, NY-BR1, MAGE A1, MAGE A3, MAGE A4, MAGE C1/CT7, and MAGE C2/CT10) was performed. CTA expression was assessed and statistically correlated with pathological and outcome data.

Results

Expression rates of CTA in salivary gland tumors ranged from 0% to 40%. MAGE A4 expression was associated with a lower tumor grade tumor grading (P = .017), and a favorable recurrence-free (P = .003), disease-specific (P = .046) and overall survival (P = .028).

Conclusions

MAGE A4 is a highly significant prognostic marker in salivary gland carcinoma; its expression is associated with low-grade histology, a low rate of distant metastasis and a favorable survival.

Level of Evidence

4.

Eribulin therapy for the treatment of patients with advanced soft tissue sarcoma

Eribulin is a structurally simplified, synthetic macrocyclic ketone analog of halichondrin B, which is a natural, polyether macrolide derived from marine sponges. Eribulin exerts its cytotoxicity by its unique microtubule dynamics inhibitory action. Eribulin was approved in 2010 by the US FDA as a third-line therapy for metastatic breast cancer patients previously treated with an anthracycline and a taxane. In 2016, it was approved for treatment of metastatic liposarcoma for patients who have progressed with anthracycline treatment. In this article, we review the pharmacokinetics, mechanism of action of eribulin with focus on preclinical and clinical data in sarcoma and also the role of miRNAs in soft tissue sarcomas.

Gankyrin: a novel promising therapeutic target for hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is known as fifth common malignancies and third common cause of cancer-related death worldwide. The identification of various mechanisms which are involved in hepatocarcinogenesis contributes in finding a variety of cellular and molecular targets for HCC diagnosis, prevention and therapy. Among various identified targets in HCC pathogenesis, Gankyrin is a crucial oncoprotein that is up-regulated in HCC and plays a pivotal role in the initiation and progression of the HCC. Oncogenic role of Gankyrin has been found to stem from inhibition of two ubiquitous tumour suppressor proteins, retinoblastoma protein (pRb) and P53, and also modulation of several vital cellular signalling pathways including Wnt/β-Catenin, NF-κB, STAT3/Akt, IL-1β/IRAK-1 and RhoA/ROCK. As a result, Gankyrin can be considered as a potential candidate for diagnosis and treatment of HCC. In this review, we summarized the physiological function and the significant role of Gankyrin as an important therapeutic target in HCC.

Current classification, treatment options, and new perspectives in the management of adipocytic sarcomas

Sarcomas are a heterogeneous group of mesenchymal tumors arising from soft tissue or bone, with an uncertain etiology and difficult classification. Soft tissue sarcomas (STSs) account for around 1% of all adult cancers. Till date, more than 50 histologic subtypes have been identified. Adipocyte sarcoma or liposarcoma (LPS) is one of the most common STS subtypes, accounting for 15% of all sarcomas, with an incidence of 24% of all extremity STSs and 45% of all retroperitoneal STSs. The new World Health Organization classification system has divided LPS into four different subgroups: atypical lipomatous tumor/well-differentiated LPS, dedifferentiated LPS, myxoid LPS, and pleomorphic LPS. These lesions can develop at any location and exhibit different aggressive potentials reflecting their morphologic diversity and clinical behavior. Patients affected by LPS should be managed in specialized multidisciplinary cancer centers. Whereas surgical resection is the mainstay of treatment for localized disease, the benefits of adjuvant and neoadjuvant chemotherapy are still unclear. Systemic treatment, particularly chemotherapy, is still limited in metastatic disease. Despite the efforts toward a better understanding of the biology of LPS, the outcome of advanced and metastatic patients remains poor. The advent of targeted therapies may lead to an improvement of treatment options and clinical outcomes. A larger patient enrollment into translational and clinical studies will help increase the knowledge of the biological behavior of LPSs, test new drugs, and introduce new methodological studies, that is, on treatment response.

Prognostic and clinicopathological significance of Gankyrin overexpression in cancers: evidence from a meta-analysis

Many studies have indicated that Gankyrin is a promising and novel prognostic tumor biomarker. However, the results of different studies remained controversial. Hence, a meta-analysis was undertaken to investigate the association between Gankyrin expression and cancer prognosis. Eligible studies were identified by searching the electronic databases PubMed, Embase, and Cochrane Library up to November 2015. Prognostic value of Gankyrin expression was evaluated by hazard ratio with 95% confidence interval (CI). Meanwhile, relative risk (RR) with 95% CI was used to assess the effects of Gankyrin expression on clinicopathological parameters. In total, ten studies with 1,326 patients were included for final analysis. A significant association was found between Gankyrin overexpression and poorer overall survival in patients with cancer (hazard ratio =1.73, 95% CI: 1.29–2.31, P=0.000). In the subgroup analysis, the association was also detected in Chinese patients and patients with cancers of the digestive system. The pooled RR indicated that Gankyrin overexpression was related to advanced tumor–node–metastasis stage (RR =0.72, 95% CI: 0.60–0.86, P=0.000), positive lymph node metastasis (RR =1.66, 95% CI: 1.41–1.94, P=0.000), and distant metastasis (RR =1.43, 95% CI: 1.20–1.70, P<0.000). The meta-analysis demonstrated that Gankyrin is a novel biomarker for predicting cancers, especially digestive system cancers, and is more suitable for predicting cancer prognoses in Asians.

Increased H3K9me3 drives dedifferentiated phenotype via KLF6 repression in liposarcoma

Liposarcoma (LPS) can be divided into 4 different subtypes, of which well-differentiated LPS (WDLPS) and dedifferentiated LPS (DDLPS) are the most common. WDLPS is typically low grade, whereas DDLPS is high grade, aggressive, and carries a worse prognosis. WDLPS and DDLPS frequently co-occur in patients. However, it is not clear whether DDLPS arises independently from WDLPS, or whether epigenomic alterations underly the histopathological differences of these subtypes. Here, we profiled 9 epigenetic marks in tumor samples from 151 patients with LPS and showed elevated trimethylation of histone H3 at Lys9 (H3K9me3) levels in DDLPS tumors. Integrated ChIP-seq and gene expression analyses of patient-derived cell lines revealed that H3K9me3 mediates differential regulation of genes involved in cellular differentiation and migration. Among these, Kruppel-like factor 6 (KLF6) was reduced in DDLPS, with increased H3K9me3 at associated regulatory regions. Pharmacologic inhibition of H3K9me3 with chaetocin decreased DDLPS proliferation and increased expression of the adipogenesis-associated factors PPARγ, CEBPα, and CEBPβ, suggesting that increased H3K9me3 may mediate DDLPS-associated aggressiveness and dedifferentiation properties. KLF6 overexpression partially phenocopied chaetocin treatment in DDLPS cells and induced phenotypic changes that were consistent with adipocytic differentiation, suggesting that the effects of increased H3K9me3 may be mediated through KLF6. In conclusion, we provide evidence of an epigenetic basis for the transition between WDLPS and DDLPS.