establishment-gastric-cancer-patient-derived-xenograft-models-primary

Establishment of Gastric Cancer Patient-derived Xenograft Models and Primary Cell Lines

The use of preclinical models to advance our understanding of tumor biology and investigate the efficacy of therapeutic agents is key to cancer research. ...

Sun Yat-sen University Cancer Center

Gastric cancer (GC) is the second cause of cancer-related death. Cisplatin (CDDP) is widely used as the standard GC treatment, but relapse and metastasis are common because of intrinsic or acquired drug resistance. The mitogen-activated protein kinase phosphatases (MAPK)-extracellular signal regulated kinases (ERK) pathway contributes to GC progression and drug resistance, but targeting the MAPK-ERK pathway is challenging in GC therapy. Here, we demonstrated that dual-specificity phosphatases 6 (DUSP6) was overexpressed in GC and predicted poor overall survival and progression-free survival. Knockdown DUSP6 inhibited GC proliferation, migration, invasion and induced apoptosis. (E/Z)-BCI hydrochloride (BCI), a DUSP6 small molecule inhibitor, increased the activity of ERK but interestingly decreased the expression of ERK response genes in BGC823, SGC7901 and CDDP-resistant SGC7901/DDP cells. BCI also caused cell death through the DNA damage response (DDR) pathway. Moreover, BCI inhibited cell proliferation, migration and invasion in a receptor-independent manner and enhanced CDDP cytotoxicity at pharmacological concentrations in the GC cells. In vivo experiments further showed that BCI enhances the antitumor effects of CDDP in cell-based xenografts and PDX models. In summary, our findings indicated that disruption of DUSP6 by BCI enhanced CDDP-induced cell death and apoptosis in GC may partly through ERK and DDR pathways. Thus, this study suggests that DUSP6 is a potential prognostic biomarker and a promising target for GC therapy.

Pharmacological inhibition of DUSP6 suppresses gastric cancer growth and metastasis and overcomes cisplatin resistance.

 Tumour cells produce energy through glycolysis and lactate dehydrogenase (LDH) is a key part of glycolysis. Elevation of serum LDH may indicate poor prognosis in primary duodenum adenocarcinoma. We aim to explore the prognostic significance of LDH in this disease.  Two hundred forty-four patients diagnosed with primary duodenum adenocarcinoma who were treated at the Sun Yat-sen Cancer Center from February 1996 to January 2016 were retrospectively analysed. We collected routine clinical data, including baseline LDH. Patients were classified into a normal LDH group (≤ 245U/L) and higher LDH group (>245U/L). Correlations of the LDH level and other clinicopathological characteristics were explored using the Chi-square test. Prognostic factors for overall survival were identified using univariate and multivariate analyses.  Two hundred seven patients (84.9%) had normal LDH levels, while 37 patients (15.1%) had abnormally high LDH levels. Higher LDH levels were significantly associated with more distant metastasis, node metastasis, poor differentiation and TNM stage Ⅲ-Ⅳ (P<0.05). Consistently, patients with node metastasis, poor differentiation and TNM stageⅢ-Ⅳ had a significantly higher median LDH level (P<0.05). The median survival of patients in the higher LDH group was significantly shorter than that of the patients in the normal LDH group (16.3 m vs. 42.5 m, =0.02). Using multivariate analysis, LDH, age and radical surgery were independent prognostic factors associated with overall survival(OS) (HR=1.571, =0.036 for LDH; HR=1.514, =0.013 for age; HR=0.248, <0.0001 for radical surgery, respectively).  For the first time, our research suggests that baseline serum LDH is an independent prognostic factor in primary duodenum adenocarcinoma patients and elevated baseline serum LDH indicates a poor prognosis.

Elevated baseline serum lactate dehydrogenase indicates a poor prognosis in primary duodenum adenocarcinoma patients.

: The antitumor activity of high-dose ascorbate has been re-evaluated recently, but the mechanism underlying cell-specific sensitivity to ascorbate has not yet been clarified.  The effects of high-dose ascorbate on gastric cancer were assessed using cancer cell lines with high and low expression of GLUT1 via flow cytometry and colony formation assays  and patient-derived xenografts . : In this study, we demonstrated that gastric cancer cells with high GLUT1 expression were more sensitive to ascorbate treatment than cells with low GLUT1 expression. GLUT1 knockdown significantly reversed the therapeutic effects of pharmacological ascorbate, while enforced expression of GLUT1 enhanced the sensitivity to ascorbate treatment. The efficacy of pharmacological ascorbate administration in mice bearing cell line-based and patient-derived xenografts was influenced by GLUT1 protein levels. Mechanistically, ascorbate depleted intracellular glutathione, generated oxidative stress and induced DNA damage. The combination of pharmacological ascorbate with genotoxic agents, including oxaliplatin and irinotecan, synergistically inhibited gastric tumor growth in mouse models. : The current study showed that GLUT1 expression was inversely correlated with sensitivity of gastric cancer cells to pharmacological ascorbate and suggested that GLUT1 expression in gastric cancer may serve as a marker for sensitivity to pharmacological ascorbate.

Pharmacological Ascorbate Suppresses Growth of Gastric Cancer Cells with GLUT1 Overexpression and Enhances the Efficacy of Oxaliplatin Through Redox Modulation.

To monitor trastuzumab resistance and determine the underlying mechanisms for the limited response rate and rapid emergence of resistance of HER2+ metastatic gastric cancer (mGC).

Liquid biopsies to track trastuzumab resistance in metastatic HER2-positive gastric cancer.

Prognostic and predictive markers are needed to predict the clinical outcomes of patients with advanced colorectal cancer (CRC) who receive standard first-line treatments. We performed a prospective cohort study in advanced CRC patients to identify a miRNA signature that could predict the benefit of receiving first-line chemotherapy for these patients. Twenty-one paired tumours and adjacent normal tissues were collected from advanced CRC patients and analysed by miRNA microarrays. Between tumour and normal tissues, 33 miRNAs were differentially expressed and was confirmed by qRT-PCR from another group of 67 patients from a prospective cohort study. A two-miRNA-based signature was obtained using the LASSO Cox regression model based on the association between the expression of each miRNA and the PFS of individual patients. Internal and external validation cohorts, including 40 and 44 patients with advanced CRC, respectively, were performed to prove the prognostic and predictive value of this signature. A signature was built based on two miRNAs, miR-125b-2-3p and miR-933. CRC patients were classified into low- and high-risk groups for disease progression based on this tool. The patients with low risk scores generally had better PFS than those with high risk scores. In the training set, the median PFS in the low- and high-risk groups were 12.00 and 7.40 months, respectively. In the internal validation set, the median PFS in the low- and high-risk groups were 9.90 and 5.10 months, respectively. In the external validation set, the median PFS in the low- and high-risk groups were 9.90 and 6.40 months, respectively. Furthermore, we detected miR-125b-2-3p associated with CRC cell sensitivity to first-line chemotherapy. Our two-miRNA-based signature was a reliable prognostic and predictive tool for tumour progression in patients with advanced CRC, and might be able to predict the benefit of receiving standard first-line chemotherapy in CRC.

A two-microRNA-based signature predicts first-line chemotherapy outcomes in advanced colorectal cancer patients.

Deregulation of protein translation control is a hallmark of cancers. Eukaryotic initiation factor 4A2 (EIF4A2) is required for mRNA binding to ribosome and plays an important role in translation initiation. However, little is known about its functions in colorectal cancer (CRC).

Article	Year
Pharmacological inhibition of DUSP6 suppresses gastric cancer growth and metastasis and overcomes cisplatin resistance. Cancer letters\| PubMed ID: 29050982	2018
Elevated baseline serum lactate dehydrogenase indicates a poor prognosis in primary duodenum adenocarcinoma patients. Journal of Cancer\| PubMed ID: 29483956	2018
Pharmacological Ascorbate Suppresses Growth of Gastric Cancer Cells with GLUT1 Overexpression and Enhances the Efficacy of Oxaliplatin Through Redox Modulation. Theranostics\| PubMed ID: 29507622	2018
Liquid biopsies to track trastuzumab resistance in metastatic HER2-positive gastric cancer. Gut\| PubMed ID: 30269082	2018
A two-microRNA-based signature predicts first-line chemotherapy outcomes in advanced colorectal cancer patients. Cell death discovery\| PubMed ID: 30588338	2018
Eukaryotic initiation factor 4A2 promotes experimental metastasis and oxaliplatin resistance in colorectal cancer. Journal of experimental & clinical cancer research : CR\| PubMed ID: 31088567	2019

Jia-huan Lu

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