CA : A Cancer Journal for Clinicians

An increasingly recognized resistance mechanism to androgen receptor (AR)-directed therapy in prostate cancer involves epithelial plasticity, in which tumor cells demonstrate low to absent AR expression and often have neuroendocrine features. The etiology and molecular basis for this 'alternative' treatment-resistant cell state remain incompletely understood. Here, by analyzing whole-exome sequencing data of metastatic biopsies from patients, we observed substantial genomic overlap between castration-resistant tumors that were histologically characterized as prostate adenocarcinomas (CRPC-Adeno) and neuroendocrine prostate cancer (CRPC-NE); analysis of biopsy samples from the same individuals over time points to a model most consistent with divergent clonal evolution. Genome-wide DNA methylation analysis revealed marked epigenetic differences between CRPC-NE tumors and CRPC-Adeno, and also designated samples of CRPC-Adeno with clinical features of AR independence as CRPC-NE, suggesting that epigenetic modifiers may play a role in the induction and/or maintenance of this treatment-resistant state. This study supports the emergence of an alternative, 'AR-indifferent' cell state through divergent clonal evolution as a mechanism of treatment resistance in advanced prostate cancer.

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Divergent clonal evolution of castration-resistant neuroendocrine prostate cancer

CircRNA has emerged as a new non-coding RNA that plays crucial roles in tumour initiation and development. ‘MiRNA sponge’ is the most reported role played by circRNAs in many tumours. The AKT/mTOR axis is a classic signalling pathway in cancers that sustains energy homeostasis through energy production activities, such as the Warburg effect, and blocks catabolic activities, such as autophagy. Additionally, the AKT/mTOR axis exerts a positive effect on EMT, which promotes tumour metastasis. We detected higher circNRIP1 expression in gastric cancer by performing RNA-seq analysis. We verified the tumour promotor role of circNRIP1 in gastric cancer cells through a series of biological function assays. We then used a pull-down assay and dual-luciferase reporter assay to identify the downstream miR-149-5p of circNRIP1. Western blot analysis and immunofluorescence assays were performed to demonstrate that the circNRIP1-miR-149-5p-AKT1/mTOR axis is responsible for the altered metabolism in GC cells and promotes GC development. We then adopted a co-culture system to trace circNRIP1 transmission via exosomal communication and RIP experiments to determine that quaking regulates circNRIP1 expression. Finally, we confirmed the tumour suppressor role of microRNA-133a-3p in vivo in PDX mouse models. We discovered that knockdown of circNRIP1 successfully blocked proliferation, migration, invasion and the expression level of AKT1 in GC cells. MiR-149-5p inhibition phenocopied the overexpression of circNRIP1 in GC cells, and overexpression of miR-149-5p blocked the malignant behaviours of circNRIP1. Moreover, it was proven that circNRIP1 can be transmitted by exosomal communication between GC cells, and exosomal circNRIP1 promoted tumour metastasis in vivo. We also demonstrated that quaking can promote circNRIP1 transcription. In the final step, the tumour promotor role of circNRIP1 was verified in PDX models. We proved that circNRIP1 sponges miR-149-5p to affect the expression level of AKT1 and eventually acts as a tumour promotor in GC.

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Circular RNA circNRIP1 acts as a microRNA-149-5p sponge to promote gastric cancer progression via the AKT1/mTOR pathway

Epigenetic dysregulation has long been recognized as a key factor contributing to tumorigenesis and tumour maintenance that can influence all of the recognized hallmarks of cancer. Despite regulatory approvals for the treatment of certain haematological malignancies, the efficacy of the first generation of epigenetic drugs (epi-drugs) in patients with solid tumours has been disappointing; however, successes have now been achieved in selected solid tumour subtypes, thanks to the development of novel compounds and a better understanding of cancer biology that have enabled precision medicine approaches. Several lines of evidence support that, beyond their potential as monotherapies, epigenetic drugs could have important roles in synergy with other anticancer therapies or in reversing acquired therapy resistance. Herein, we review the mechanisms by which epi-drugs can modulate the sensitivity of cancer cells to other forms of anticancer therapy, including chemotherapy, radiation therapy, hormone therapy, molecularly targeted therapy and immunotherapy. We provide a critical appraisal of the preclinical rationale, completed clinical studies and ongoing clinical trials relating to combination therapies incorporating epi-drugs. Finally, we propose and discuss rational clinical trial designs and drug development strategies, considering key factors including patient selection, tumour biomarker evaluation, drug scheduling and response assessment and study end points, with the aim of optimizing the development of such combinations. The use of epigenetic drugs (epi-drugs) as single agents according to a ‘one size fits all’ approach has generally resulted in disappointing therapeutic activity. In this Review, the mechanisms by which epi-drugs can modulate the sensitivity of cancer cells to other diverse forms of anticancer therapy are described, and completed and ongoing clinical trials relating to combination therapies incorporating epi-drugs are discussed. In addition, clinical trial designs and drug development strategies aimed at optimizing the development of such combinations are outlined.

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Combining epigenetic drugs with other therapies for solid tumours - past lessons and future promise.

// Shivakumar Keerthikumar 1,* , Lahiru Gangoda 1,* , Michael Liem 1 , Pamali Fonseka 1 , Ishara Atukorala 1 , Cemil Ozcitti 1 , Adam Mechler 2 , Christopher G. Adda 1 , Ching-Seng Ang 3 and Suresh Mathivanan 1 1 Department of Biochemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia 2 Department of Chemistry, La Trobe Institute for Molecular Science, La Trobe University, Melbourne, Victoria, Australia 3 Bio21 Institute, University of Melbourne, Victoria, Australia * These authors have contributed equally to this work Correspondence to: Suresh Mathivanan, email: // Keywords : exosomes, ectosomes, proteogenomics, extracellular vesicles, integrated OMICs analysis Received : January 27, 2015 Accepted : March 18, 2015 Published : April 12, 2015 Abstract Extracellular vesicles (EVs) include the exosomes (30-100 nm) that are produced through the endocytic pathway via the multivesicular bodies and the ectosomes (100-1000 nm) that are released through the budding of the plasma membrane. Despite the differences in the mode of biogenesis and size, reliable markers that can distinguish between exosomes and ectosomes are non-existent. Moreover, the precise functional differences between exosomes and ectosomes remains poorly characterised. Here, using label-free quantitative proteomics, we highlight proteins that could be exploited as markers to discriminate between exosomes and ectosomes. For the first time, a global proteogenomics analysis unveiled the secretion of mutant proteins that are implicated in cancer progression through tumor-derived EVs. Follow up integrated bioinformatics analysis highlighted the enrichment of oncogenic cargo in exosomes and ectosomes. Interestingly, exosomes induced significant cell proliferation and migration in recipient cells compared to ectosomes confirming the oncogenic nature of exosomes. These findings ascertain that cancer cells facilitate oncogenesis by the secretion of mutant and oncoproteins into the tumor microenvironment via exosomes and ectosomes. The integrative proteogenomics approach utilized in this study has the potential to identify disease biomarker candidates which can be later assayed in liquid biopsies obtained from cancer patients.

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Proteogenomic analysis reveals exosomes are more oncogenic than ectosomes

High-level expression of NAD(P)H: quinoneoxidoreductase 1 (NQO1) has been correlated with many types of human cancers, suggesting that NQO1 plays important roles in tumor occurrence and progression. This study attempted to explore the role of NQO1 in tumor progression and prognostic evaluation of non-small cell lung cancer (NSCLC). Total 164 tissue samples, including 150 NSCLC paired with the adjacent non-tumor tissues and 14 normal lung tissues, were picked-up for immunohistochemical (IHC) staining of the NQO1 protein, and immunofluorescence (IF) staining was also performed to detect the subcellular localization of the NQO1 protein in A549 human lung cancer cells. The correlation between NQO1 expression and clinicopathological characteristics were evaluated by Chi-square test and Fisher’s exact tests. The disease-free survival (DFS) and overall survival (OS) rates of NSCLC patients were calculated by the Kaplan-Meier method, and univariate and multivariate analyses were performed using the Cox proportional hazards regression model. The NQO1 protein showed a mainly cytoplasmic staining pattern in lung cancer cells, including adenocarcinoma and squamous cell carcinoma (SCC). Both positive rate and strongly positive rate of NQO1 protein expression were significantly higher in NSCLC (59.3% and 28.0%) than that in adjacent non tumor (8.0% and 1.3%) and normal lung tissues (0%). The positive rate of NQO1 was related with clinical stage and lymph node metastasis, and the strongly positive rate of NQO1 protein was significantly correlated with tumor size, poor differentiation, advanced clinical stage and lymph node metastasis in NSCLC. Additionally, survival analyses showed that the patients with NQO1 positive expression had lower OS rates compared with those with NQO1 negative expression in the groups of T1-2, T3-4, without LN metastasis and stage I-II of NSCLC, respectively; however, in the groups of patients with LN metastasis or III-IV stages, OS rate was not correlated with NQO1 expression status. Moreover, multivariate analysis suggested that NQO1 emerged as a significant independent prognostic factor along with tumor size, differentiation, lymph node metastasis and clinical stage in patients with NSCLC. NQO1 is upregulated in NSCLC, and it may be a useful poor prognostic biomarker and a potential therapeutic target for patients with NSCLC.

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NQO1 protein expression predicts poor prognosis of non-small cell lung cancers

Background
NQO1 (NAD(P)H: quinone oxidoreductase-1), located on chromosome 16q22, functions primarily to protect normal cells from oxidant stress and electrophilic attack. Recent studies have revealed that NQO1 is expressed at a high level in most human solid tumors including those of the colon, breast, pancreas, ovaries and thyroid, and it has also been detected following the induction of cell cycle progression and proliferation of melanoma cells. In this study, we aimed to investigate the clinicopathological significance of upregulated NQO1 protein expression in squamous cell carcinomas (SCCs) of the uterine cervix.

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NQO1 overexpression is associated with poor prognosis in squamous cell carcinoma of the uterine cervix

// Tiefeng Jin 1, 2, * , Hoe Suk Kim 1, * , Sul Ki Choi 1, 3 , Eun Hye Hwang 1 , Jisu Woo 1 , Han Suk Ryu 4 , Kwangsoo Kim 5 , Aree Moon 6 and Woo Kyung Moon 1, 3 1 Department of Radiology, Seoul National University Hospital, Jongno-gu, Seoul 03080, Korea 2 Department of Pathology & Cancer Research Center, Yanbian University Medical College, Yanji 133002, China 3 Department of Biomedical Science, Seoul National University College of Medicine, Seoul National University, Jongno-gu, Seoul 03080, Korea 4 Department of Pathology, Seoul National University Hospital, Jongno-gu, Seoul 03080, Korea 5 Division of Clinical Bioinformatics, Biomedical Research Institute, Seoul National University Hospital, Jongno-gu, Seoul 03080, Korea 6 Duksung Innovative Drug Center College of Pharmacy, Duksung Women's University, Dobong-gu, Seoul 01369, Korea * These authors have contributed equally to this work Correspondence to: Woo Kyung Moon, email: moonwk@snu.ac.kr Keywords: SerpinB2, SerpinE1, metastasis, microRNA-200c/141, triple negative breast cancer Received: June 06, 2016      Accepted: February 12, 2017      Published: February 24, 2017 ABSTRACT The microRNA-200 (miR-200) family is associated with tumor metastasis and poor patient prognosis. We found that miR-200c/141 cluster overexpression upregulated SerpinB2 in the MDA-MB-231 triple-negative (TN) breast cancer cell line. We observed transcription factor (c-Jun, c-Fos, and FosB) upregulation, nuclear localization of c-Jun, and increased SerpinB2 promoter-directed chloramphenicol acetyltransferase activity in miR-200c/141 cluster-overexpressing cells relative to controls. Additionally, miR-124a and miR-26b, which directly target SepinB2, were downregulated compared to controls. In mouse xenograft models, miR-200c/141 cluster overexpression promoted lymph node and lung metastasis, and siRNA-mediated SerpinB2 knockdown decreased lung metastasis, suggesting that SerpinB2 mediates miR-200c/141-induced lung metastasis. We also explored the clinical significance of SerpinB2 protein status through analysis of primary breast tumor samples and The Cancer Genome Atlas (TCGA) data. High SerpinB2 levels were associated with reduced survival and increased lymph node metastasis in breast cancer patients. SerpinB2 was overexpressed in the TN breast cancer subtype as compared to the luminal subtype. The present study demonstrates that SerpinB2 promotes miR-200c/141 cluster overexpression-induced breast cancer cell metastasis, and SerpinB2 overexpression correlates with increased metastatic potential and unfavorable outcomes in breast cancer patients. SerpinB2 may be a useful biomarker for assessing metastasis risk in breast cancer patients.

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microRNA-200c/141 upregulates SerpinB2 to promote breast cancer cell metastasis and reduce patient survival.

Background: Ezrin is a cytoskeletal protein that is involved in tumor growth and invasion. It has been suggested that Ezrin expression plays an important role in tumor metastasis. This study is aimed to investigate the clinicopathological significance of Ezrin overexpression in gastric adenocarcinomas. Methods: Ezrin protein expression was examined by immunohistochemistry in 26 normal gastric mucosa, 32 dysplasia, and 277 gastric adenocarcinomas. The relationship between Ezrin expression and the clinicopathological features of gastric cancers was analyzed. In addition, a gastric cancer cell line, MKN-1, was also used for immunofluorescence staining to evaluate the distribution of Ezrin protein. Results: Ezrin protein located in the cytoplasm and/or membrane in the migrating gastric cancer cells, and it mainly concentrated at the protrusion site; however, only cytoplasmic distribution was observed in the non-migrating cancer cells by immunofluorescence staining. The positive rate of Ezrin protein expression was significantly higher in gastric adenocarcinoma and dysplasia compared with that in the normal gastric mucosa. Moreover, expression frequency of Ezrin protein increased significantly in lymph node metastasis and late clinical stages. Consistently, strong expression of Ezrin was significantly correlated with poor prognosis of gastric cancer. Conclusion: The detection of Ezrin expression can be used as the marker for early diagnosis and prognosis of gastric adenocarcinoma. Virtual Slides: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/ vs/2303598677653946

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Ezrin overexpression predicts the poor prognosis of gastric adenocarcinoma

// Sul Ki Choi 1, 2, * , Hoe Suk Kim 1, * , Tiefeng Jin 1, 3 , Woo Kyung Moon 1, 2 1 Department of Radiology, Seoul National University Hospital, Jongno-gu, Seoul 03080, Korea 2 Department of Biomedical Sciences, Seoul National University College of Medicine, Jongno-gu, Seoul 03080, Korea 3 Department of Pathology and Cancer Research Center, Yanbian University Medical College, Yanji 133002, China * These authors have contributed equally to this work Correspondence to: Woo Kyung Moon, email: moonwk@snu.ac.kr Keywords: triple-negative breast cancer (TNBC), lysyl oxidase-like 4 (LOXL4), collagen, tumor progression, overall survival Received: September 24, 2016      Accepted: December 20, 2016      Published: January 02, 2017 ABSTRACT Lysyl oxidase (LOX) family genes catalyze collagen cross-link formation. To determine the effects of lysyl oxidase-like 4 (LOXL4) expression on breast tumor formation and metastasis, we evaluated primary tumor growth and lung metastasis in mice injected with LOXL4-knockdown MDA-MB-231 triple-negative human breast cancer cells. In addition, we analyzed overall survival in breast cancer patients based on LOXL4 expression using a public online database. In the mouse xenograft model, LOXL4 knockdown increased primary tumor growth and lung colonization as well as collagen I and IV, lysine hydroxylase 1 and 2, and prolyl 4-hydroxylase subunit alpha 1 and 2 levels. Second harmonic generation imaging revealed that LOXL4 knockdown resulted in the thickening of collagen bundles within tumors. In addition, weak LOXL4 expression was associated with poor overall survival in breast cancer patients from the BreastMark dataset, and this association was strongest in triple-negative breast cancer patients. These results demonstrate that weak LOXL4 expression leads to remodeling of the extracellular matrix through induction of collagen synthesis, deposition, and structural changes. These alterations in turn promote tumor growth and metastasis and are associated with poor clinical outcomes in triple-negative breast cancer.

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Tiefeng Jin

Papers

NQO1 protein expression predicts poor prognosis of non-small cell lung cancers

NQO1 overexpression is associated with poor prognosis in squamous cell carcinoma of the uterine cervix

microRNA-200c/141 upregulates SerpinB2 to promote breast cancer cell metastasis and reduce patient survival.

Ezrin overexpression predicts the poor prognosis of gastric adenocarcinoma

LOXL4 knockdown enhances tumor growth and lung metastasis through collagen-dependent extracellular matrix changes in triple-negative breast cancer