A clinically relevant orthotopic implantation nude mouse model of human epithelial ovarian cancer--based on consecutive observation

Enforced Expression of METCAM/MUC18 Decreases In Vitro Motility and Invasiveness and Tumorigenesis and In Vivo Tumorigenesis of Human Ovarian Cancer BG-1 Cells

OBJECTIVES

We tested if METCAM/MUC18 overexpression also plays a suppressor role in another human ovarian cancer cell line, BG-1, in addition to the SK-OV3 cell line.

METHODS

Human ovarian cancer BG-1 cells were transfected with METCAM/MUC18 cDNA and G418-resistant clones expressing different levels of METCAM/MUC18 were isolated. These clones were used to test the effects of enforced expression of METCAM/MUC18 on in vitro motility, invasiveness, and anchorage-independent colony formation (in vitro tumorigenesis), and in vivo tumorigenesis after SC injection and after IP injection in female athymic nude mice.

RESULTS

Overexpression of METCAM/MUC18 reduced in vitro motility and invasiveness of BG-1 cells and anchorage-independent colony formation (in vitro tumor formation). Higher expression of METCAM/MUC18 in BG-1 cells significantly reduced in vivo tumor proliferation of the BG-1 cells after IP injection (orthotopic route) of the clones in female nude mice, though it did not significantly affect in vivo tumor proliferation after SC injection (non-orthotopic route).

CONCLUSION

Similar to SK-OV3 cells, METCAM/MUC18 also plays a suppressor role in the progression of BG-1 cells in a xenograft mouse model.

Modelling the Functions of Polo-Like Kinases in Mice and Their Applications as Cancer Targets with a Special Focus on Ovarian Cancer

Polo-like kinases (PLKs) belong to a five-membered family of highly conserved serine/threonine kinases (PLK1-5) that play differentiated and essential roles as key mitotic kinases and cell cycle regulators and with this in proliferation and cellular growth. Besides, evidence is accumulating for complex and vital non-mitotic functions of PLKs. Dysregulation of PLKs is widely associated with tumorigenesis and by this, PLKs have gained increasing significance as attractive targets in cancer with diagnostic, prognostic and therapeutic potential. PLK1 has proved to have strong clinical relevance as it was found to be over-expressed in different cancer types and linked to poor patient prognosis. Targeting the diverse functions of PLKs (tumor suppressor, oncogenic) are currently at the center of numerous investigations in particular with the inhibition of PLK1 and PLK4, respectively in multiple cancer trials. Functions of PLKs and the effects of their inhibition have been extensively studied in cancer cell culture models but information is rare on how these drugs affect benign tissues and organs. As a step further towards clinical application as cancer targets, mouse models therefore play a central role. Modelling PLK function in animal models, e.g., by gene disruption or by treatment with small molecule PLK inhibitors offers promising possibilities to unveil the biological significance of PLKs in cancer maintenance and progression and give important information on PLKs' applicability as cancer targets. In this review we aim at summarizing the approaches of modelling PLK function in mice so far with a special glimpse on the significance of PLKs in ovarian cancer and of orthotopic cancer models used in this fatal malignancy.

Establishment of two ovarian cancer orthotopic xenograft mouse models for in vivo imaging: A comparative study

Orthotopic tumor animal models are optimal for preclinical research of novel therapeutic interventions. The aim of the present study was to compare two types of ovarian cancer orthotopic xenograft (OCOX) mouse models, i.e. cellular orthotopic injection (COI) and surgical orthotopic implantation (SOI), regarding xenograft formation rate, in vivo imaging, tumor growth and metastasis, and tumor microenvironment. The tumor formation and progression were monitored by bioluminescent in vivo imaging. Cell proliferation and migration abilities were detected by EdU and scratch assays, respectively. Expression of α-SMA, CD34, MMP2, MMP9, vimentin, E-cadherin and Ki67 in tumor samples were detected by immunohistochemistry. As a result, we successfully established COI- and SOI-OCOX mouse models using ovarian cancer cell lines ES2 and SKOV3. The tumor formation rate in the COI and SOI models were 87.5 and 100%, respectively. Suspected tumor cell leakage occurred in 37.5% of the COI models. The SOI xenografts grew faster, held larger primary tumors, and were more metastatic than the COI xenografts. The migration and proliferation properties of the cells that generated SOI xenografts were significantly starker than those deriving COI xenografts in vitro. The tumor cells in SOI xenografts exhibited a mesenchymal phenotype and proliferated more actively than those in the COI xenografts. Additionally, compared with the COI tumors, the SOI tumors contained more cancer associated fibroblasts, matrix metallopeptidase 2 and 9. In conclusion, SOI is a feasible and reliable technique to establish OCOX mouse models mimicking the clinical process of ovarian cancer growth and metastasis, although SOI is more technically difficult and time-consuming than COI.

Fuling Granule, a Traditional Chinese Medicine Compound, Suppresses Cell Proliferation and TGFβ-Induced EMT in Ovarian Cancer

The compound fuling granule (CFG) is a traditional Chinese drug which has been used to treat ovarian cancer in China for over twenty years. Nevertheless, the underlying molecular mechanism of its anti-cancer effect remains unclear. In this study, microarray data analysis was performed to search differentially expressed genes in CFG-treated ovarian cancer cells. Several cell cycle and epithelial-mesenchymal transition (EMT) related genes were identified. The microarray analyses also revealed that CFG potentially regulates EMT in ovarian cancer. We also found that, functionally, CFG significantly suppresses ovarian cancer cell proliferation by cell cycle arrest, apoptosis and senescence and the AKT/GSK-3β pathway is possibly involved. Additionally, the invasion and migration ability of ovarian cancer induced by TGFβ is significantly suppressed by CFG. In conclusion, our results demonstrated that CFG suppresses ovarian cancer cell proliferation as well as TGFβ1-induced EMT in vitro. Finally, we discovered that CFG suppresses tumor growth and distant metastasis in vivo. Overall, these findings provide helpful clues to design novel clinical treatments against cancer.

Orthotopic xenografts of RCC retain histological, immunophenotypic and genetic features of tumours in patients

Renal cell carcinoma (RCC) is an aggressive malignancy with limited responsiveness to existing treatments. In vivo models of human cancer, including RCC, are critical for developing more effective therapies. Unfortunately, current RCC models do not accurately represent relevant properties of the human disease. The goal of this study was to develop clinically relevant animal models of RCC for preclinical investigations. We transplanted intact human tumour tissue fragments orthotopically in immunodeficient mice. The xenografts were validated by comparing the morphological, phenotypic and genetic characteristics of the kidney tumour tissues before and after implantation. Twenty kidney tumours were transplanted into mice. Successful tumour growth was detected in 19 cases (95%). The histopathological and immunophenotypic features of the xenografts and those of the original tumours largely overlapped in all cases. Evaluation of genetic alterations in a subset of 10 cases demonstrated that the grafts largely retained the genetic features of the pre-implantation RCC tissues. Indeed, primary tumours and corresponding grafts displayed identical VHL mutations. Moreover, an identical pattern of DNA copy amplification or loss was observed in 6/10 cases (60%). In summary, orthotopic engrafting of RCC tissue fragments can be successfully used to generate animal models that closely resemble RCC in patients. These models will be invaluable for in vivo preclinical drug testing and for deeper understanding of kidney carcinogenesis. The raw data of the SNP array analysis has been submitted to the GEO database (Accession No. GSE29062).