Haohao Wang

Estrogen receptor-α36 is involved in development of acquired tamoxifen resistance via regulating the growth status switch in breast cancer cells

Acquired tamoxifen (TAM) resistance limits the therapeutic benefit of TAM in patients with hormone‐dependent breast cancer. The switch from estrogen‐dependent to growth factor‐dependent growth is a critical step in this process. However, the molecular mechanisms underlying this switch remain poorly understood. In this study, we established a TAM resistant cell sub line (MCF‐7/TAM) from estrogen receptor‐α (ER‐α66) positive breast cancer MCF‐7 cells by culturing ER‐α66‐positive MCF‐7 cells in medium plus 1 μM TAM over 6 months. MCF‐7/TAM cells were then found to exhibit accelerated proliferation rate together with enhanced in vitro migratory and invasive ability. And the estrogen receptor‐α36 (ER‐α36), a novel 36‐kDa variant of ER‐α66, was dramatically overexpressed in this in vitro model, compared to the parental MCF‐7 cells. Meanwhile, the expression of epidermal growth factor receptor (EGFR) in MCF‐7/TAM cells was significantly up‐regulated both in mRNA level and protein level, and the expression of ER‐α66 was greatly down‐regulated oppositely. In the subsequent studies, we overexpressed ER‐α36 in MCF‐7 cells by stable transfection and found that ER‐α36 transfected MCF‐7 cells (MCF‐7/ER‐α36) similarly exhibited decreased sensitivity to TAM, accelerated proliferative rate and enhanced in vitro migratory and invasive ability, compared to empty vector transfected MCF‐7 cells (MCF‐7/V). Real‐time qPCR and Western blotting analysis revealed that MCF‐7/ER‐α36 cells possessed increased EGFR expression but decreased ER‐α66 expression both in mRNA level and protein level, compared to MCF‐7/V cells. This change in MCF‐7/ER‐α36 cells could be reversed by neutralizing anti‐ER‐α36 antibody treatment. Furthermore, knock‐down of ER‐α36 expression in MCF‐7/TAM cells resulted in reduced proliferation rate together with decreased in vitro migratory and invasive ability. Decreased EGFR mRNA and protein expression as well as increased ER‐α66 mRNA expression were also observed in MCF‐7/TAM cells with down‐regulated ER‐α36 expression. In addition, blocking EGFR/ERK signaling in MCF‐7/ER‐α36 cells could restore the expression of ER‐α66 partly, suggesting a regulatory function of EGFR/ERK signaling in down‐regulation of ER‐α66 expression. In conclusion, our results indicated for the first time a regulatory role of ER‐α36 in up‐regulation of EGFR expression and down‐regulation of ER‐α66 expression, which could be an underlying mechanism for the growth status switch in breast tumors that contribute to the generation of acquired TAM resistance. And ER‐α36 could be considered a potential new therapeutic target in breast tumors which have acquired resistance to TAM.

Estrogen-independent effects of ER-α36 in ER-negative breast cancer.

Estrogen receptor-alpha 36 (ER-α36) is a variant of ER-α that has been found to be expressed in conventional ER (ER-α66)-negative breast cancer cell lines and human breast cancer samples. In this study, we found that, using immunohistochemical study, ER-α36 expression was significantly higher in ER-negative tumors than in ER-positive tumors although the expression was not associated with other clinicopathological characteristics. We then constructed an ER-α36-specific microRNA hairpin vector and established stable ER-α36 knockdown cells, and found that the knockdown cells were more sensitive to paclitaxel; the c-Jun N-terminal kinase pathway appeared to be involved in the mechanism. Downregulation of ER-α36 also resulted in decreased migration and invasion. These changes were estrogen independent. Our findings indicated that target ER-α36 may be a strategy for treating ER-negative breast cancers.

Luteolin exerts a marked antitumor effect in cMet-overexpressing patient-derived tumor xenograft models of gastric cancer

BackgroundAberrated activation of cMet in gastric cancer contributes to tumor growth, angiogenesis and metastasis. cMet-overexpressing gastric cancer has a poor prognosis because of high tumor metastasis and limited therapeutic options. Luteolin is a common dietary flavonoid with antitumor properties. However, the antitumor effect of luteolin on cMet-overexpressing gastric cancer remain unclear.MethodsTwo cMet-overexpressing patient-derived human tumor xenograft (PDTX) models of gastric cancer were established, and treated with luteolin or vehicle to evaluate the antitumor effects of luteolin. Tumor specimens were subjected to H&E staining and immunohistochemistry. MKN45 and SGC7901 cells that show high cMet expression were treated with varying concentrations of luteolin and evaluated by western blot, cell viability, apoptosis, migration, and invasion assays.ResultsLuteolin inhibited the tumor growth in cMet-overexpressing PDTX models. Immunohistochemistry demonstrated that expression of cMet, MMP9 and Ki-67 were significantly down-regulated. Luteolin inhibited proliferation, promoted apoptosis and reduced the invasiveness of MKN45 and SGC7901 cells. Western blot revealed that luteolin promoted the activation of apoptosis-related proteins, caspase-3 and PARP-1, and down-regulated the invasion-associated protein, MMP9. Further studies demonstrated that luteolin decreased the expression and phosphorylation of cMet, and downstream phosphorylation of Akt and ERK. In addition, luteolin down-regulated phosphorylated Akt independently of cMet. Blocking Akt and/or ERK with the PI3K inhibitor, LY294002, or the ERK inhibitor, PD98059, induced down-regulation of MMP9 and up-regulation of cleaved caspase-3 and PARP-1, resembling the effects of luteolin.ConclusionsOur findings ,for the first time, demonstrate that luteolin exerts marked antitumor effects in cMet-overexpressing PDTX models of gastric cancer, through a mechanism likely involving cMet/Akt/ERK signaling. These findings indicate that luteolin may act as a potential therapeutic option for cMet-overexpressing gastric cancer.

Advances in Combination of Antiangiogenic Agents Targeting VEGF-binding and Conventional Chemotherapy and Radiation for Cancer Treatment

&NA; Despite great efforts and resources being devoted to treatment, the incidence and mortality of numerous cancers have not decreased in recent decades. This is a result of the resistance of cancer cells to chemotherapeutic agents and radio‐therapy. The development of antiangiogenic agents that target vascular endothelial growth factor (VEGF) provides a new option for treatment of cancer. Major advances have been achieved with cancer therapy based on antiangiogenic VEGF‐targeted agents in the past few years, and some of the recently approved therapies are now being used in daily clinical practice. A further challenge is finding a more efficacious combination of antiangiogenic VEGF‐targeted therapies and conventional radio‐ and chemotherapies. This review outlines the current preclinical and clinical cancer treatments using optimized combinations of antiangiogenic VEGF‐targeted agents and conventional radiochemotherapy and highlights that better scheduling for the combination of radiochemotherapy and antiangiogenic VEGF‐targeted agents should be developed to achieve better treatment outcomes.

LncRNA UCA1 in anti-cancer drug resistance

The pivotal role of the long non-coding RNA (lncRNA) urothelial carcinoma associated 1 (UCA1) in anti-cancer drug resistance has been confirmed in many cancers. Overexpression of lncRNA UCA1 correlates with resistance to chemotherapeutics such as cisplatin, gemcitabine, 5-FU, tamoxifen, imatinib and EGFR-TKIs, whereas lncRNA UCA1 knockdown restores drug sensitivity. These studies highlight the potential of lncRNA UCA1 as a diagnostic and prognostic biomarker, and a therapeutic target in malignant tumors. In this review, we address the role of lncRNA UCA1 in anti-cancer drug resistance and discuss its potential in future clinical applications.The pivotal role of the long non-coding RNA (lncRNA) urothelial carcinoma associated 1 (UCA1) in anti-cancer drug resistance has been confirmed in many cancers. Overexpression of lncRNA UCA1 correlates with resistance to chemotherapeutics such as cisplatin, gemcitabine, 5-FU, tamoxifen, imatinib and EGFR-TKIs, whereas lncRNA UCA1 knockdown restores drug sensitivity. These studies highlight the potential of lncRNA UCA1 as a diagnostic and prognostic biomarker, and a therapeutic target in malignant tumors. In this review, we address the role of lncRNA UCA1 in anti-cancer drug resistance and discuss its potential in future clinical applications.

Assessment of a Novel VEGF Targeted Agent Using Patient-Derived Tumor Tissue Xenograft Models of Colon Carcinoma with Lymphatic and Hepatic Metastases

The lack of appropriate tumor models of primary tumors and corresponding metastases that can reliably predict for response to anticancer agents remains a major deficiency in the clinical practice of cancer therapy. It was the aim of our study to establish patient-derived tumor tissue (PDTT) xenograft models of colon carcinoma with lymphatic and hepatic metastases useful for testing of novel molecularly targeted agents. PDTT of primary colon carcinoma, lymphatic and hepatic metastases were used to create xenograft models. Hematoxylin and eosin staining, immunohistochemical staining, genome-wide gene expression analysis, pyrosequencing, qRT-PCR, and western blotting were used to determine the biological stability of the xenografts during serial transplantation compared with the original tumor tissues. Early passages of the PDTT xenograft models of primary colon carcinoma, lymphatic and hepatic metastases revealed a high degree of similarity with the original clinical tumor samples with regard to histology, immunohistochemistry, genes expression, and mutation status as well as mRNA expression. After we have ascertained that these xenografts models retained similar histopathological features and molecular signatures as the original tumors, drug sensitivities of the xenografts to a novel VEGF targeted agent, FP3 was evaluated. In this study, PDTT xenograft models of colon carcinoma with lymphatic and hepatic metastasis have been successfully established. They provide appropriate models for testing of novel molecularly targeted agents.

Establishment of a PDTT xenograft model of gastric carcinoma and its application in personalized therapeutic regimen selection.

BACKGROUND/AIMS Lack of appropriate tumor models that reliably predict response to anticancer agents remains a major deficiency in the clinical practice of personalized cancer therapy. The aim of our study was to establish a patient-derived tumor tissue (PDTT) xenograft model of gastric carcinoma for personalized cancer therapeutic regimen selection and testing of novel molecularly targeted agents. METHODOLOGY Patient-derived tumor tissue of primary gastric carcinoma was used to create the xenograft model. After 11 weeks, xenografts were harvested for serial transplantation. H&E staining, immunohistochemical staining and Western blotting were used to determine biological stability of the xenograft during serial transplantation compared with the original tumor tissue. Drug sensitivities of the xenograft to bevacizumab (Avastin), FP3 and cetuximab were evaluated.

Molecular biomarkers of colorectal cancer： prognostic and predictive tools for clinical practice

Colorectal cancer remains one of the most common types of cancer and leading causes of cancer death worldwide. Although we have made steady progress in chemotherapy and targeted therapy, evidence suggests that the majority of patients undergoing drug therapy experience severe, debilitating, and even lethal adverse drug events which considerably outweigh the benefits. The identification of suitable biomarkers will allow clinicians to deliver the most appropriate drugs to specific patients and spare them ineffective and expensive treatments. Prognostic and predictive biomarkers have been the subjects of many published papers, but few have been widely incorporated into clinical practice. Here, we want to review recent biomarker data related to colorectal cancer, which may have been ready for clinical use.

BRCA1/2 associated hereditary breast cancer.

Breast cancer is one of the leading causes of death in women today. Some of the patients are hereditary, with a large proportion characterized by mutation in BRCA1 and/or BRCA2 genes. In this review, we provide an overview of these two genes, focusing on their relationship with hereditary breast cancers. BRCA1/2 associated hereditary breast cancers have unique features that differ from the general breast cancers, including alterations in cellular molecules, pathological bases, biological behavior, and a different prevention strategy. But the outcome of BRCA1/2 associated hereditary breast cancers still remains controversial; further studies are needed to elucidate the nature of BRCA1/2 associated hereditary breast cancers.

Prevalence of JC Virus in Chinese Patients with Colorectal Cancer

Background JCV is a DNA polyomavirus very well adapted to humans. Although JCV DNA has been detected in colorectal cancers (CRC), the association between JCV and CRC remains controversial. In China, the presence of JCV infection in CRC patients has not been reported. Here, we investigated JCV infection and viral DNA load in Chinese CRC patients and to determine whether the JCV DNA in peripheral blood (PB) can be used as a diagnostic marker for JCV-related CRC. Methodology/Principal Findings Tumor tissues, non-cancerous tumor-adjacent tissues and PB samples were collected from 137 CRC patients. In addition, 80 normal colorectal tissue samples from patients without CRC and PB samples from 100 healthy volunteers were also harvested as controls. JCV DNA was detected by nested PCR and glass slide-based dot blotting. Viral DNA load of positive samples were determined by quantitative real-time PCR. JCV DNA was detected in 40.9% (56/137) of CRC tissues at a viral load of 49.1 to 10.3×104 copies/µg DNA. Thirty-four (24.5%) non-cancerous colorectal tissues (192.9 to 4.4×103 copies/µg DNA) and 25 (18.2%) PB samples (81.3 to 4.9×103 copies/µg DNA) from CRC patients were positive for JCV. Tumor tissues had higher levels of JCV than non-cancerous tissues (P = 0.003) or PB samples (P<0.001). No correlation between the presence of JCV and demographic or medical characteristics was observed. The JCV prevalence in PB samples was significantly associated with the JCV status in tissue samples (P<0.001). Eleven (13.8%) normal colorectal tissues and seven (7.0%) PB samples from healthy donors were positive for JCV. Conclusions/Significance JCV infection is frequently present in colorectal tumor tissues of CRC patients. Although the association between JCV presence in PB samples and JCV status in tissue samples was identified in this study, whether PB JCV detection can serve as a marker for JCV status of CRC requires further study.