Establishment of an orthotopic transplantation tumor model of hepatocellular carcinoma in mice

AIM:To improve the outcome of orthotopic transplantation in a mouse model,we used an absorbable gelatin sponge(AGS) in nude mice to establish an orthotopic implantation tumor model.METHODS:MHCC-97L hepatocellular carcinoma(HCC)cells stably expressing the luciferase gene were injected into the subcutaneous region of nude mice.One week later,the ectopic tumors were harvested and transplanted into the left liver lobe of nude mice.The AGS was used to establish the nude mouse orthotopic implantation tumor model.The tumor suppressor gene,paired box gene 5(PAX5),which is a tumor suppressor in HCC,was transfected into HCC cells to validate the model.Tumor growth was measured by bioluminescence imaging technology.Semi-quantitative reverse transcription polymerase chain reaction(RT-PCR) and histopathology were used to confirm the tumorigenicity of the implanted tumor from the MHCC-97L cell line.RESULTS:We successfully developed an orthotopic transplantation tumor model in nude mice with the use of an AGS.The success rate of tumor transplantation was improved from 60% in the control group to 100% in the experimental group using AGS.The detection of fluorescent signals showed that tumors grew in all live nude mice.The mice were divided into 3 groups:AGS-,AGS+/PAX5-and AGS+/PAX5 +.Tumor size was significantly smaller in PAX5 transfected nude mice compared to control mice(P < 0.0001).These fluorescent signal results were consistent with observations made during surgery.Pathologic examination further confirmed that the tissues from the ectopic tumor were HCC.Results from RT-PCR proved that the HCC originated from MHCC-97L cells.CONCLUSION:Using an AGS is a convenient and efficient way of establishing an indirect orthotopic liver transplantation tumor model with a high success rate.

3D tumor model biofabrication

Animal models have been extensively used in cancer pathology studies and drug discovery.These models,however,fail to reflect the complex human tumor microenvironment and do not allow for high-throughput drug screening in more human-like physiological conditions.Three-dimensional(3D)cancer models present an alternative to automated high-throughput cancer drug discovery and oncology.In this review,we highlight recent technology innovations in building 3D tumor models that simulate the complex human tumor microenvironment and responses of patients to treatment.We discussed various biofabrication technologies,including 3D bioprinting techniques developed for characterizing tumor progression,metastasis,and response to treatment.

Development for the lung tumor model of newborn mice induced by diethylstilbestrol

Objective： To explore a economical and effective method for building lung tumor model induced by diethylstibestrol （DES）. Methods： The carcinogenic effect of neonatal mice treated by DES was studied. The newborn mice were divided into DES, Urethan （U） and U ＋ DES groups. U group was given in 500 mg/kg dose by ip at postnatal 14 day, DES group was administered by ip at the 1 d, 8 d, 15 d in the dose of 1/7, 2/7 and 4/7 LD50 of the day when they were injected respectively for DES （I）, DES （M）, DES （H） groups. Until 26 weeks, they were anatomized and checked the formation of tumors. The organ index, tumor incidence ratio and mean number of tumors were calculated. Results： Lung tumors were apparently induced in tested neonatal mice. The incidence of lung tumor of DES （L, M, H） groups were 16.7%, 22.4% and 43.1% respectively, the U ＋ DES （L, M, H） groups were 70.4%, 90.9% and 70.8% respectively, and the U group was 53.1%. The mean numbers of lung tumors of U ＋ DES （L, M） groups were higher than those of the DES （L, M） groups respectively （P 〈 0.05）. Conclusion： The higher ratio of lung tumor incidence had been induced by DES and U joined action to neonatal mice, which may be a useful and economical method to establish a lung tumor model induced by DES.

A 3-D in vitro tumor model for investigation of bacteria-mediated gene delivery

Introduction Cancer is an attractive target of gene therapy and currently represents the disease in most clinical trials[1]. Strategies for cancer gene therapy include: (1) stimulation of immune responses to tumor cells,(2) delivery of specific enzymes

Different initial conditions in fuzzy Tumor model

One of the best ways for better understanding of biological experiments is mathematical modeling. Modeling cancer is one of the complicated biological modeling that has uncertainty. Therefore, fuzzy models have studied because of their application in achievement uncertainty in modeling. Overall, the main purpose of this modeling is creating a new view of complex phenomena. In this paper, fuzzy differential equation model consisting of tumor, the immune system and normal cells has been studied. Model derived from a classical model DePillis in 2003, which some parameters from a clinical point of view can be described in the region. In this model, by considering fuzzy parameters from clinical point of view, the three-dimensional fuzzy tumor cells in terms of time and membership function are pictured and region of uncertainties are determined. To access the uncertainty area we use fuzzy differential inclusion method that is one of the including methods of solving differential equations. Also, different initial conditions on the model are inserted and the results of them are analyzed because tumor has different treatment in different initial conditions. Results show that fuzzy models in the best way justify what happens in the reality.

Three-dimensional breast cancer tumor models based on natural hydrogels:a review

Breast cancer is the most common cancer in women and one of the deadliest cancers worldwide.According to the distribution of tumor tissue,breast cancer can be divided into invasive and non-invasive forms.The cancer cells in invasive breast cancer pass through the breast and through the immune system or systemic circulation to different parts of the body,forming metastatic breast cancer.Drug resistance and distant metastasis are the main causes of death from breast cancer.Research on breast cancer has attracted extensive attention from researchers.In vitro construction of tumor models by tissue engineering methods is a common tool for studying cancer mechanisms and anticancer drug screening.The tumor microenvironment consists of cancer cells and various types of stromal cells,including fibroblasts,endothelial cells,mesenchymal cells,and immune cells embedded in the extracellular matrix.The extracellular matrix contains fibrin proteins(such as types Ⅰ,Ⅱ,Ⅲ,Ⅳ,Ⅵ,and Ⅹ collagen and elastin)and glycoproteins(such as proteoglycan,laminin,and fibronectin),which are involved in cell signaling and binding of growth factors.The current traditional two-dimensional(2D)tumor models are limited by the growth environment and often cannot accurately reproduce the heterogeneity and complexity of tumor tissues in vivo.Therefore,in recent years,research on three-dimensional(3D)tumor models has gradually increased,especially 3D bioprinting models with high precision and repeatability.Compared with a 2D model,the 3D environment can better simulate the complex extracellular matrix components and structures in the tumor microenvironment.Three-dimensional models are often used as a bridge between 2D cellular level experiments and animal experiments.Acellular matrix,gelatin,sodium alginate,and other natural materials are widely used in the construction of tumor models because of their excellent biocompatibility and non-immune rejection.Here,we review various natural scaffold materials and construction methods involved in 3D tissue-engineered tumor models,as a reference for research in the field of breast cancer.

An Efficient Technique for One-Dimensional Fractional Diffusion EquationModel for Cancer Tumor

This study intends to examine the analytical solutions to the resulting one-dimensional differential equation of acancer tumor model in the frame of time-fractional order with the Caputo-fractional operator employing a highlyefficient methodology called the q-homotopy analysis transform method.So,the preferred approach effectivelyfound the analytic series solution of the proposed model.The procured outcomes of the present frameworkdemonstrated that this method is authentic for obtaining solutions to a time-fractional-order cancer model.Theresults achieved graphically specify that the concerned paradigm is dependent on arbitrary order and parametersand also disclose the competence of the proposed algorithm.

Evolution of Tumor Model: From Animal Model of Tumor to Tumor Model in Animal

Patient derived xenograft (PDX) is defined as a growth of patients’ tumor in the xenograft setting. The evolution of cancer model in animal has a century old history. The most single reason that exerted the pressure on the traditional animal model of cancer to evolve to PDX is that the traditional models have not delivered as expected and traditional models have not predicted clinical success. In spite of well above 50 drugs developed and approved for oncology over the last several decades, there remains a nirking paucity of clinical success as a reminder that this war on cancer riding on the animal model is far from won. In a backbreaking attempt to analyze the failure, the limitation of the “model” system appeared to be the most rational cause of this shortcoming. It was more of a failure to test a drug rather than a failure to make a drug that stunted our collective growth and success in cancer research. PDX is the product of this age-old failure and its fitness is currently tested in virtually all organ-type solid tumors. This review will present and appraise PDX model in the context of its evolution, its future promise, its limitations and more specifically, the current content of PDX in different solid tumors including breast, lung, colorectal, prostrate, GBM, pancreatic, hepatocellular carcinoma and melanoma.

3D bioprinting of in vitro porous hepatoma models:establishment,evaluation,and anticancer drug testing

Traditional tumor models do not tend to accurately simulate tumor growth in vitro or enable personalized treatment and are particularly unable to discover more beneficial targeted drugs.To address this,this study describes the use of threedimensional(3D)bioprinting technology to construct a 3D model with human hepatocarcinoma SMMC-7721 cells(3DP-7721)by combining gelatin methacrylate(GelMA)and poly(ethylene oxide)(PEO)as two immiscible aqueous phases to form a bioink and innovatively applying fluorescent carbon quantum dots for long-term tracking of cells.The GelMA(10%,mass fraction)and PEO(1.6%,mass fraction)hydrogel with 3:1 volume ratio offered distinct pore-forming characteristics,satisfactorymechanical properties,and biocompatibility for the creation of the 3DP-7721 model.Immunofluorescence analysis and quantitative real-time fluorescence polymerase chain reaction(PCR)were used to evaluate the biological properties of the model.Compared with the two-dimensional culture cell model(2D-7721)and the 3D mixed culture cell model(3DM-7721),3DP-7721 significantly improved the proliferation of cells and expression of tumor-related proteins and genes.Moreover,we evaluated the differences between the three culture models and the effectiveness of antitumor drugs in the three models and discovered that the efficacy of antitumor drugs varied because of significant differences in resistance proteins and genes between the three models.In addition,the comparison of tumor formation in the three models found that the cells cultured by the 3DP-7721 model had strong tumorigenicity in nude mice.Immunohistochemical evaluation of the levels of biochemical indicators related to the formation of solid tumors showed that the 3DP-7721 model group exhibited pathological characteristics of malignant tumors,the generated solid tumors were similar to actual tumors,and the deterioration was higher.This research therefore acts as a foundation for the application of 3DP-7721 models in drug development research.

Modeling One Dimensional Two-Cell Model with Tumor Interaction Using Krylov Subspace Methods

A brain tumor occurs when abnormal cells grow, sometimes very rapidly, into an abnormal mass of tissue. The tumor can infect normal tissue, so there is an interaction between healthy and infected cell. The aim of this paper is to propose some efficient and accurate numerical methods for the computational solution of one-dimensional continuous basic models for the growth and control of brain tumors. After computing the analytical solution, we construct approximations of the solution to the problem using a standard second order finite difference method for space discretization and the Crank-Nicolson method for time discretization. Then, we investigate the convergence behavior of Conjugate gradient and generalized minimum residual as Krylov subspace methods to solve the tridiagonal toeplitz matrix system derived.

The construction of in vitro tumormodels based on 3D bioprinting

Cancer is characterized by a high fatality rate,complex molecular mechanism,and costly therapies.The microenvironment of a tumor consists of multiple biochemical cues and the interaction between tumor cells,stromal cells,and extracellular matrix plays a key role in tumor initiation,development,angiogenesis,invasion and metastasis.To better understand the biological features of tumor and reveal the critical factors of therapeutic treatments against cancer,it is of great significance to build in vitro tumor models that could recapitulate the stages of tumor progression and mimic tumor behaviors in vivo for efficient and patient-specific drug screening and biological studies.Since conventional tissue engineering methods of constructing tumor models always fail to simulate the later stages of tumor development due to the lack of ability to build complex structures and angiogenesis potential,three-dimensional(3D)bioprinting techniques have gradually found its applications in tumor microenvironment modeling with accurate composition and well-organized spatial distribution of tumor-related cells and extracellular components in the past decades.The capabilities of building tumor models with a large range of scale,complex structures,multiple biomaterials and vascular network with high resolution and throughput make 3D bioprinting become a versatile platform in bio-manufacturing aswell as inmedical research.In this review,wewill focus on 3D bioprinting strategies,design of bioinks,current 3D bioprinted tumor models in vitro classified with their structures and propose future perspectives.

Identification of cancer stem cells provides novel tumor models for drug discovery

Cancer stem cells(CSCs)have received considerable attention from the research community since they were first reported in human acute myeloid leukemia 15 years ago.Accumulating evidence suggests that CSCs are responsible for tumor initiation and progression,drug resistance,and metastasis in both liquid and solid tumors.These findings lead to the development of novel compounds targeting CSC populations that is becoming increasingly important for eradicating CSCs in heterogeneous tumor masses and to cure the cancer.Since 2003,we have participated in CSC studies and encountered crucial early events in the field.This article reviews the history of CSC biology,clarifies the term and its definition,and further addresses the issue of how to utilize CSCs in therapeutic target discovery and drug development based on our substantial experience.

Establishment of a Tumor-bearing Mouse Model Stably Expressing EGFP Labeled Human MUC1 VNTRs

Two eukaryotic vectors expressing 9 tandem repeats of human MUCI（VNTR）, VR1012-VNTR, and pEGFP-VNTR, were constructed by cloning VNTR gene into VR1012 and pEGFP, respectively. VNTR stably expressing murine Lewis lung carcinoma（LLC） cell line（VNTR^＋ LLC） was established by Lipofectamine-mediated transfection of pEGFP-VNTR into LLC cells. The EGFP expression was observed under a fluorescent microscope and VNTR expression in VNTR^＋ LLC cells was confirmed by means of Western blotting. A syngenic graft tumor model was generated by subcutaneous injection of VNTR^＋ LLC cells into C57/BL6 mice and tumor size increased rapidly with time and in a cell qumber dependent manner. VNTR mRNA expression in the tumor formed was confirmed by RT-PCR. After the third immunization mice were challenged subcutaneously with 5×10^5 VNTR^＋ LLC cells, a significant reduction of subcutaneous tumor growth was observed in the groups immunized with VNTR plasmid DNA compared with that in the groups immunized with the vector DNA alone. Thus, the suppression of subcutaneous tumor was antigen-specific. This model is useful for the development of tumor vaccines targeting MUCI VNTRs.

Establishment of a Tumor-bearing Mouse Model Stably Expressing Human Tumor Antigens Survivin and MUC1 VNTRs

The eukaryotic vectors VR1012 expressing survivin or 33 tandem repeats of human mucin 1（MUC1）（VNTRs）,namely,VR1012-S and VR1012-VNTR（VNTR=variable number of tandem repeat）,were constructed by cloning survivin and VNTR genes into VR1012,respectively.The eukaryotic vector pEGFP expressing survivin and MUC1 VNTRs fusion gene pEGFP-MS was also constructed.Mouse melanoma cell line（B16） stably expressing survivin and MUC1 VNTRs（MS ＋ B16） was established by Lipofectamine-mediated transfection of pEGFP-MS into B16 cells.EGFP expression in MS ＋ B16 cells was observed using a fluorescent microscope and survivin and MUC1 VNTRs（MS） expression was confirmed by means of Western blot analysis.A syngenic graft tumor model was generated by subcutaneous injection of MS ＋ B16 cells into C57/BL6 mice and tumor size increased rapidly with time in a cell number dependent manner.After the third immunization,mice were challenged subcutaneously with 5×l0 5 MS ＋ B16 cells.Compared with that of the negative control immunized with phosphate-buffered saline（PBS）,a significant reduction of tumor growth was observed in groups immunized with survivin plasmid DNA and MUC1 VNTRs plasmid DNA.Thus,the suppression of subcutaneous tumor was antigen-specific.This model is useful for the development of tumor vaccines targeting survivin and MUCI VNTRs.

Numerical analysis of fractional-order tumor model

In this paper, the tumor-immune dynamics are simulated by solving a nonlinear system of differential equations. The fractional-order mathematical model incorporated with three Michaelis-Menten terms to indicate the saturated effect of immune response, the limited immune response to the tumor and to account the self-limiting production of cytokine interleukin-2. Two types of treatments were considered in the mathematical model to demonstrate the importance of immunotherapy. The limiting values of these treatments were considered, satisfying the stability criteria for fractional differential system. A graphical analysis is made to highlight the effects of antigenicity of the tumor and the fractionM-order derivative on the tumor mass.

Effects of Lvy noise and immune delay on the extinction behavior in a tumor growth model

The combined effects of Ltvy noise and immune delay on the extinction behavior in a tumor growth model are explored, The extinction probability of tumor with certain density is measured by exit probability. The expression of the exit probability is obtained using the Taylor expansion and the infinitesimal generator theory. Based on numerical calculations, it is found that the immune delay facilitates tumor extinction when the stability index α〈 1, but inhibits tumor extinction when the stability index α 〉 1. Moreover, larger stability index and smaller noise intensity are in favor of the extinction for tumor with low density. While for tumor with high density, the stability index and the noise intensity should be reduced to promote tumor extinction.

Advances in prostate cancer research models:From transgenic mice to tumor xenografting models

The identification of the origin and molecular characteristics of prostate cancer(PCa)has crucial implications for personalized treatment.The development of effective treatments for PCa has been limited;however,the recent establishment of several transgenicmouse lines and/or xenografting models is better reflecting the disease in vivo.With appropriate models,valuable tools for elucidating the functions of specific genes have gone deep into prostate development and carcinogenesis.In the present review,we summarize a number of important PCa research models established in our laboratories(PSA-Cre-ERT2/PTEN transgenic mouse models,AP-OX model,tissue recombination-xenografting models and PDX models),which represent advances of translational models from transgenic mouse lines to human tumor xenografting.Better understanding of the developments of these models will offer new insights into tumor progression and may help explain the functional significance of genetic variations in PCa.Additionally,this understanding could lead to new modes for curing PCa based on their particular biological phenotypes.

Prediction of tumor biological characteristics in different colorectal cancer liver metastasis animal models using^(18)F-FDG and^(18)F-FLT

Background: Positron emission tomography(PET) is a noninvasive method to characterize different metabolic activities of tumors, providing information for staging, prognosis, and therapeutic response of patients with cancer. The aim of this study was to evaluate the feasibility of18F-fludeoxyglucose(18F-FDG) and 3’-deoxy-3’-18F-fluorothymidine(18F-FLT) PET in predicting tumor biological characteristics of colorectal cancer liver metastasis.Methods: The uptake rate of18F-FDG and18F-FLT in SW480 and SW620 cells was measured via an in vitro cell uptake assay. The region of interest was drawn over the tumor and liver to calculate the maximum standardized uptake value ratio(tumor/liver) from PET images in liver metastasis model. The correlation between tracer uptake in liver metastases and VEGF, Ki67 and CD44 expression was evaluated by linear regression.Results: Compared to SW620 tumor-bearing mice, SW480 tumor-bearing mice presented a higher rate of liver metastases. The uptake rate of18F-FDG in SW480 and SW620 cells was 6.07% ± 1.19% and2.82% ± 0.15%, respectively(t = 4.69, P = 0.04); that of18F-FLT was 24.81% ± 0.45% and 15.57% ± 0.66%, respectively(t = 19.99, P < 0.001). Micro-PET scan showed that all parameters of FLT were significantly higher in SW480 tumors than those in SW620 tumors. A moderate relationship was detected between metastases in the liver and18F-FLT uptake in primary tumors(r = 0.73, P = 0.0019).18F-FLT uptake was also positively correlated with the expression of CD44 in liver metastases(r = 0.81, P = 0.0049).Conclusions: The uptake of18F-FLT in metastatic tumor reflects different biological behaviors of colon cancer cells.18F-FLT can be used to evaluate the metastatic potential of colorectal cancer in nude mice.

Existence and Uniqueness of Almost Periodic Solution for a Mathematical Model of Tumor Growth

This article is concerned with a mathematical model of tumor growth governed by 2nd order diffusion equation . The source of mitotic inhibitor is almost periodic and time-dependent within the tissue. The system is set up with the initial condition C(r, 0) = C0(r) and Robin type inhomogeneous boundary condition . Under certain conditions we show that there exists a unique solution for this model which is almost periodic.

Early changes of hepatic hemodynamics measured by functional CT perfusion in a rabbit model of liver tumor

BACKGROUND:Early detection and treatment of hepatocellular carcinoma is crucial to improving the patients’ survival.The hemodynamic changes caused by tumors can be serially measured using CT perfusion.In this study,we used a CT perfusion technique to demonstrate the changes of hepatic hemodynamics in early tumor growth,as a proof-of-concept study for human early hepatocellular carcinoma.METHODS:VX2 tumors were implanted in the liver of ten New Zealand rabbits.CT perfusion scans were made 1 week(early) and 2 weeks(late) after tumor implantation.Ten normal rabbits served as controls.CT perfusion parameters were obtained at the tumor rim,normal tissue surrounding the tumor,and control liver;the parameters were hepatic blood flow,hepatic blood volume,mean transit time,permeability of capillary vessel surface,hepatic arterial index,hepatic arterial perfusion and hepatic portal perfusion.Microvessel density and vascular endothelial growth factor were correlated.RESULTS:At the tumor rim,compared to the controls,hepatic blood flow,hepatic blood volume,permeability of capillary vessel surface,hepatic arterial index,and hepatic arterial perfusion increased,while mean transit time and hepatic portal perfusion decreased on both early and late scans(P<0.05).Hepatic arterial index increased(135%,P<0.05),combined with a sharp increase in hepatic arterial perfusion(182%,P<0.05) and a marked decrease in hepatic portal perfusion(-76%,P<0.05) at 2 weeks rather than at 1 week(P<0.05).Microvessel density and vascular endothelial growth factor showed significant linear correlations with hepatic blood flow,permeability of capillary vessel surface and hepatic arterial index,but not with hepatic blood volume or mean transit time.CONCLUSION:The CT perfusion technique demonstrated early changes of hepatic hemodynamics in this tumor model as proof-of-concept for early hepatocellular carcinoma detection in humans.