Kuifeng He

Patient-derived human tumour tissue xenografts in immunodeficient mice: a systematic review.

Mouse cancer models have consistently been used to qualify new anticancer drugs in the development of human clinical trials. Rodent tumour models currently being used and which include transgenic tumour models, and those generated by planting human tumour cell lines subcutaneously in immunodeficient mice, do not sufficiently represent clinical cancer characteristics, especially with regard to metastasis and drug sensitivity. The increasingly used patient-derived human tumour tissue (PDTT) xenografts models implanted subcutaneously or in subrenal capsule in immunodeficient mice, such as athymic nude mice or severe combined immune deficient (SCID) mice, may provide a more accurate reflection of human tumour biological characteristics than tumour cell lines. The ability to passage patients’ fresh tumour tissues into large numbers of immunodeficient mice provides possibilities for better preclinical testing of new therapies for the treatment and better outcome for cancer. In this review, we outline the methods of establishing xenograft models, discuss the biological stability of PDTT xenograft models and demonstrate their roles in developing new anticancer drugs and testing therapeutic regimens in cancer patients.

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.

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.

Aflibercept (VEGF Trap): one more double-edged sword of anti-VEGF therapy for cancer?

The use of vascular endothelial growth factor (VEGF)-targeted agents for treating cancer has increased dramatically over recent decades. These drugs provide considerable benefits in terms of progression-free (PFS) or overall (OS) survival for cancer patients. Of particular importance to clinicians treating cancer patients by using VEGF-targeted agents is VEGF-inhibition-induced hypertension, proteinuria, thrombosis and hemorrhage. Aflibercept is a new, successful example of targeting VEGF for therapy of solid tumors. Though results from phase I and II clinical trials demonstrated aflibercept is well tolerated, it inevitably has severe adverse effects unique to this class of agents. In this review, we discuss the adverse effects associated with aflibercept (VEGF Trap), focusing on vascularassociated hypertension, proteinuria, hemorrhage, and thrombosis, and further discuss the mechanisms, significance, and potential management of these adverse effects.

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.

Differential response to EGFR- and VEGF-targeted therapies in patient-derived tumor tissue xenograft models of colon carcinoma and related metastases

Heterogeneity in primary tumors and related metastases may result in failure of antitumor therapies, particularly in targeted therapies for the treatment of cancer. In this study, patient-derived tumor tissue (PDTT) xenograft models of colon carcinoma with lymphatic and hepatic metastases were used to evaluate the response to EGFR- and VEGF-targeted therapies. Our results showed that primary colon carcinoma and its corresponding lymphatic and hepatic metastases have a different response rate to anti-EGFR (cetuximab) and anti-VEGF (bevacizumab) therapies. However, the underlying mechanism of these types of phenomenon is still unclear. To investigate whether such phenomena may result from the heterogeneity in primary colon carcinoma and related metastases, we compared the expression levels of cell signaling pathway proteins using immunohistochemical staining and western blotting, and the gene status of KRAS using pyrosequencing in the same primary colon carcinoma and its corresponding lymphatic and hepatic metastatic tissues which were used for establishing the PDTT xenograft models. Our results showed that the expression levels of EGFR, VEGF, Akt/pAkt, ERK/pERK, MAPK/pMAPK, and mTOR/pmTOR were different in primary colon carcinoma and matched lymphatic and hepatic metastases although the KRAS gene status in all cases was wild-type. Our results indicate that the heterogeneity in primary colon carcinoma and its corresponding lymphatic and hepatic metastases may result in differences in the response to dual-inhibition of EGFR and VEGF.

Gallbladder carcinoma incidentally encountered during laparoscopic cholecystectomy: how to deal with it

Gallbladder cancer (GBC), characterised by rapid progression and a poor prognosis with a high mortality rate, is a complex disease to treat. Incidental gallbladder carcinoma (IGBC) is defined as carcinoma of the gallbladder suspected for the first time during cholecystectomy or accidentally found on histological examination of the gallbladder. With the increasingly widespread acceptance of laparoscopic cholecystectomy (LC) and difficulties in diagnosing GBC preoperatively, the number of cases of IGBC during and after LC has increased. However, management of IGBC is a difficult issue in the absence of established guidelines. Problems associated with IGBC related to LC are the decisions of whether, when and how to perform additional surgery. Controversy remains regarding the effectiveness of additional resection in different stages of GBC. This review gives an overview of IGBC related to LC, and further discusses the preoperative, intraoperative and postoperative diagnosis and management of IGBC during LC.