Aberrant cystatin-C expression in blood from patients with breast cancer is a suitable marker for monitoring tumor burden

The present study was performed to evaluate the efficacy of circulating cystatin-C as a tumor monitoring biomarker at different clinical time points in patients with breast cancer over a long-term follow-up period. In addition, the secretory rate of circulating cystatin-C from cancer tissue was investigated by comparing the blood and tissue expression levels of cystatin-C. Blood samples from healthy volunteers (40 males and 40 females) were obtained at yearly health examinations if laboratory and imaging abnormalities were not detected. Blood samples from 34 patients with breast cancer were obtained at 205 different time points of clinical progression. Blood levels of cystatin-C were measured using ELISA and the tissue levels were measured using immunohistochemistry. No age-associated effect was observed in male and female blood cystatin-C levels. The positivity rate was 46% in patients (38/83) and 40% in samples collected at different time points (82/205). Blood cystatin-C levels were lowest following surgery compared with patients with systemic metastasis (P<0.001). The sensitivity, specificity and accuracy rates of ELISA were 53.6, 63.6 and 53.9%, respectively. The concordance rate between blood and tissue expression was 38%. The main reason for discordance between tissue and serum expression of cytostatin-C came from low serum positivity in samples showing tissue cytostatin-C (3/11, 27%). The specificity between cytostatin-C and CA-125 was highest in tumor absence state. In conclusion, elevated blood levels of cystatin-C were observed in 40% of breast cancer cases and were tumor-volume dependent. However, the concordance rate between tissue and blood was quite low, suggesting tumor heterogeneity of cystatin-C expression or co-acting pathway activation, such as cathepsin D. As one-third of breast cancer tissues express cystatin-C without cancer antigen 15-3 elevation, cystatin-C may represent a good tumor-monitoring marker in breast cancer.ope

Renal Cell Carcinoma Is Abrogated by p53 Stabilization through Transglutaminase 2 Inhibition

In general, expression of transglutaminase 2 (TGase 2) is upregulated in renal cell carcinoma (RCC), resulting in p53 instability. Previous studies show that TGase 2 binds to p53 and transports it to the autophagosome. Knockdown or inhibition of TGase 2 in RCC induces p53-mediated apoptosis. Here, we screened a chemical library for TGase 2 inhibitors and identified streptonigrin as a potential therapeutic compound for RCC. Surface plasmon resonance and mass spectroscopy were used to measure streptonigrin binding to TGase 2. Mass spectrometry analysis revealed that streptonigrin binds to the N-terminus of TGase 2 (amino acids 95⁻116), which is associated with inhibition of TGase 2 activity in vitro and with p53 stabilization in RCC. The anti-cancer effects of streptonigrin on RCC cell lines were demonstrated in cell proliferation and cell death assays. In addition, a single dose of streptonigrin (0.2 mg/kg) showed marked anti-tumor effects in a preclinical RCC model by stabilizing p53. Inhibition of TGase 2 using streptonigrin increased p53 stability, which resulted in p53-mediated apoptosis of RCC. Thus, targeting TGase 2 may be a new therapeutic approach to RCC.ope

Regulation of proliferation and invasion by the IGF signalling pathway in Epstein-Barr virus-positive gastric cancer

Several carcinomas including gastric cancer have been reported to contain Epstein-Barr virus (EBV) infection. EBV-associated gastric cancer (EBVaGC) is classified as one of four molecular subtypes of gastric cancer by The Cancer Genome Atlas (TCGA) group with increased immune-related signatures. Identification of EBV-dependent pathways with significant biological roles is needed for EBVaGC. To compare the biological changes between AGS gastric epithelial cells and EBV-infected AGS (AGS-EBV) cells, proliferation assay, CCK-8 assay, invasion assay, cell cycle analysis, RT-PCR, Western blot and ELISA were performed. BI836845, a humanized insulin-like growth factor (IGF) ligand-neutralizing antibody, was used for IGF-related signalling pathway inhibition. AGS-EBV cells showed slower proliferating rate and higher sensitivity to BI836845 compared to AGS cells. Moreover, invasiveness of AGS-EBV was increased than that of AGS, and BI836845 treatment significantly decreased the invasiveness of AGS-EBV. Although no apoptosis was detected, entry into the S phase of the cell cycle was delayed in BI836845-treated AGS-EBV cells. In conclusion, AGS-EBV cells seem to modulate their proliferation and invasion through the IGF signalling pathway. Inhibition of the IGF signalling pathway therefore could be a potential therapeutic strategy for EBVaGC.ope

Rho GTPase RhoJ is Associated with Gastric Cancer Progression and Metastasis

Rho GTPases play a pivotal role in tumor progression by regulating tumor cell migration and invasion. However, the role of Rho GTPases in gastric cancer (GC) remains unexplored. This study aimed to investigate the clinical implications of RhoJ, which is an uncharted member of Rho family. RhoJ expression in human GC cell lines and surgical specimens from GC patients were analyzed. Moreover, in vitro gain-of-function analysis was performed to evaluate the malignant phenotypes of RhoJ-overexpressing GC cells. The extent of RhoJ expression varied among GC cell lines and GC patients. YCC-9 cell line displayed the strongest expression, while YCC-10, -11, and -16 showed scant expressions. Of the 70 GC patients, 34 (48.6%) had RhoJ expression in their GC tissue, and patients with high RhoJ expression had more diffuse type GC (73.5% vs. 41.7%), were at more advanced stages (stage III, IV: 85.3% vs. 58.4%), and had more frequent metastasis (47.1% vs. 11.1%), denoting that RhoJ has a potential role in GC progression and metastasis. High RhoJ expression significantly correlated with poor overall survival and recurrence-free survival after surgical resection of gastric cancer. Finally, In vitro gain-of-function experiments showed 41.3% enhanced motility and 60.4% enhanced invasiveness in RhoJ-overexpressing GC cells compared to control, with negligible difference in cell proliferation. Collectively, high RhoJ expression is an independent negative prognostic factor for the survival outcome of GC and correlated with the increased cell motility and invasiveness.ope

A novel TP53-KPNA3 translocation defines a de novo treatment-resistant clone in osteosarcoma

Osteosarcoma is the most common primary bone cancer. It can be cured by aggressive surgery and chemotherapy, but outcomes for metastatic or chemoresistant disease remain dismal. Cancer sequencing studies have shown that the p53 pathway is dysregulated in nearly every case, often by translocation; however, no studies of osteosarcoma evolution or intratumor heterogeneity have been done to date. We studied a patient with chemoresistant, metastatic disease over the course of 3 years. We performed exome sequencing on germline DNA and DNA collected from tumor at three separate time points. We compared variant calls and variant allele frequencies between different samples. We identified subclonal mutations in several different genes in the primary tumor sample and found that one particular subclone dominated subsequent tumor samples at relapse. This clone was marked by a novel TP53-KPNA3 translocation and loss of the opposite-strand wild-type TP53 allele. Future research must focus on the functional significance of such clones and strategies to eliminate them.ope

Genetic alterations and their clinical implications in gastric cancer peritoneal carcinomatosis revealed by whole-exome sequencing of malignant ascites

Peritoneal carcinomatosis accompanied by malignant ascites is a major cause of death of advanced gastric cancer (GC). To comprehensively characterize the underlying genomic events involved in GC peritoneal carcinomatosis, we analyzed whole-exome sequences of normal gastric tissues, primary tumors, and malignant ascites from eight GC patients. We identified a unique mutational signature biased toward C-to-A substitutions in malignant ascites. In contrast, the patients who received treatment of adjuvant chemotherapy showed a high rate of C-to-T substitutions along with hypermutation in malignant ascites. Comparative analysis revealed several candidate mutations for GC peritoneal carcinomatosis: recurrent mutations in COL4A6, INTS2, and PTPN13; mutations in druggable genes including TEP1, PRKCD, BRAF, ERBB4, PIK3CA, HDAC9, FYN, FASN, BIRC2, FLT3, ROCK1, CD22, and PIK3C2B; and mutations in metastasis-associated genes including TNFSF12, L1CAM, DIAPH3, ROCK1, TGFBR1, MYO9B, NR4A1, and RHOA. Notably, gene ontology analysis revealed the significant enrichment of mutations in the Rho-ROCK signaling pathway-associated biological processes in malignant ascites. At least four of the eight patients acquired somatic mutations in the Rho-ROCK pathway components, suggesting the possible relevance of this pathway to GC peritoneal carcinomatosis. These results provide a genome-wide molecular understanding of GC peritoneal carcinomatosis and its clinical implications, thereby facilitating the development of effective therapeutics.ope

Comprehensive immune profiling and immune-monitoring using body fluid of patients with metastatic gastric cancer

BACKGROUND: The aim of this study is to profile the cytokines and immune cells of body fluid from metastatic gastric cancer (mGC), and evaluate the potential role as a prognostic factor and the feasibility as a predictive biomarker or monitoring source for immune checkpoint inhibitor. METHODS: Body fluid including ascites and pleural fluid were obtained from 55 mGC patients and 24 matched blood. VEGF-A, IL-10, and TGF-β1 were measured and immune cells were profiled by fluorescence assisted cell sorting (FACS). RESULTS: VEGF-A and IL-10 were significantly higher in body fluid than in plasma of mGC. Proportion of T lymphocytes with CD69 or PD-1, memory T cell marked with CD45RO, and number of Foxp3+ T regulatory cells (Tregs) were significantly higher in body fluid than those in blood of mGC. Proportion of CD8 T lymphocyte with memory marker (CD45RO) and activation marker (HLA-DR), CD3 T lymphocyte with PD-1, and number of FoxP3+ Tregs were identified as independent prognostic factors. When patients were classified by molecular subgroups of primary tumor, VEGF-A was significantly higher in genomically stable (GS)-like group than that in chromosomal instability (CIN)-like group while PD-L1 positive tumor cells (%) showed opposite results. Monitoring immune dynamics using body fluid was also feasible. Early activated T cell marked with CD25 was significantly increased in chemotherapy treated group. CONCLUSIONS: By analyzing cytokines and proportion of immune cells in body fluid, prognosis of patients with mGC can be predicted. Immune monitoring using body fluid may provide more effective treatment for patients with mGC.ope

Association of the ABCB1 gene polymorphisms 2677G>T/A and 3435C>T with clinical outcomes of paclitaxel monotherapy in metastatic breast cancer patients

BACKGROUND: ABCB1 is responsible for multidrug resistance, the principal mechanism by which many cancers develop resistance to chemotherapeutic drugs. There is a controversy whether ABCB1 gene polymorphisms correlate with survival and response in cancer patients treated with chemotherapy. We evaluated the association between clinical outcome (safety and efficacy) of paclitaxel monotherapy in metastatic breast cancer patients with ABCB1 gene polymorphisms 2677G>T/A or 3435C>T. PATIENTS AND METHODS: Patients with metastatic breast cancer were treated with 175 mg/m(2) paclitaxel per 3-week cycle. Peripheral blood mononuclear cells from patients were used to genotype ABCB1 2677G>T/A and 3435C>T polymorphisms. Genotypes were investigated for their association with tumor response, survival, toxicity, and chemoresistance. RESULTS: ABCB1 3435 CT showed a significantly lower disease control rate than the CC genotype (P = 0.025). ABCB1 3435 CT was correlated with shorter overall survival (OS) in Cox regression analysis (P = 0.026). The 2677 GG genotype showed a significant association with chemoresistance to paclitaxel and anthracycline (P = 0.04 and 0.04, respectively). None of the ABCB1 genotypes correlated with toxicity. CONCLUSIONS: ABCB1 genotypes may be a predictor of paclitaxel activity as well as a prognostic factor in metastatic breast cancer patientsope

PTEN loss and level of HER2 amplification is associated with trastuzumab resistance and prognosis in HER2-positive gastric cancer

Background: Trastuzumab is an active agent against human epidermal growth factor receptor 2 (HER2)-positive gastric cancer (GC). This study aimed to characterize resistance to trastuzumab-based front-line chemotherapy in HER2+ GC patients and to establish factors predictive of this resistance. Results: Among 129 HER2+ GC patients, 25% displayed rapid disease progression within 4 months from initiation of therapy. These patients showed a higher rate of signet ring cell histology, bone metastasis, poor performance status, frequent loss of PTEN expression, and low HER2 amplification index compared with patients who were progression-free for at least 4 months. In contrast, there was no significant difference in the frequency of the PIK3R1 variant. Multivariate analyses confirmed two independent molecular predictors for trastuzumab resistance: loss of PTEN expression and low HER2 amplification index (<5). Patients with one or both molecular predictors at diagnosis exhibited worse progression-free and overall survival compared to those without risk factors (p < 0.001 and p = 0.001, respectively). Conclusion: In HER2+ GC patients, loss of PTEN expression and low HER2 AI correlated with resistance to trastuzumab-based therapy and dismal prognosis. Since patients harboring these molecular predictors are unlikely to respond to trastuzumab-based therapy, other novel therapeutic targets needed to be considered. Methods: HER2+ GC patients who were treated with trastuzumab in combination with either 5-fluorouracil/cisplatin or capecitabine/cisplatin were enrolled. Clinicopathologic features and molecular alterations of HER2, phosphoinositide 3-kinase regulatory subunit 1 (PIK3R1), and phosphatase and tensin homolog (PTEN) were correlated with treatment outcome. Factors predictive of resistance were also explored.ope

유방암에서의 BRCA2 유전자형에 따른 HAT activity : taxanes 저항성의 새로운 기전

Dept. of Medical Science/박사Taxanes are a class of anticancer agents, which stabilize polymerized microtubules and enhance microtubule assembly, and thus arrest the cell cycle in G2/M phases, leading to cell death. Taxanes resistance has been attributed to a variety of mechanisms. But the evidence for this resistant mechanism is weak. In the present study, we defined the resistance mechanism to taxanes based on BRCA2 genotype. First, we screened taxanes-sensitivity by MTT assay. We identified a significant difference in chemosensitivity related to BRCA2 372Asn>His genotype. This difference was reflected in a higher IC50 for heterozygous polymorphic type than for the wild type. The BRCA2 and P/CAF expression were no difference among groups. However, we showed that the interaction of BRCA2 and P/CAF decreased by 2-fold in the heterozygous polymorphic type compared with the wild type. HAT activity was also relatively higher in BRCA2 wild type cells compared with heterozygous polymorphic cells. Functional validation of selected SNP by HDAC inhibition was used to indirectly confirm that our selection was reasonable. To directly confirm, we established cell lines with an altered BRCA2 genotype. The cell lines with an altered BRCA2 genotype were restored to taxanes-sensitivity. The functional restoration by transfection of altered genotypes suggests that HAT activity and BRCA2-P/CAF interaction related to the BRCA2 genotype may be a potential mechanism of taxanes resistance in breast cancer. In conclusion, HAT activity based on BRCA2-P/CAF interaction had potental role of taxanes-sensitivity in breast cancer cells.ope