Comparison of immune responses and intestinal flora in epicutaneously sensitized BALB/c or C57BL/6 mouse models of food allergy

Cutaneous exposure to food allergens through a disrupted skin barrier is recognized as an important cause of food allergy,and the cutaneous sensitized mouse model has been established to investigate relevant allergic disorders.However,the role of different genetic backgrounds of mice on immune responses to food allergens upon epicutaneous sensitization is largely unknown.In this study,two strains of mice,i.e.,the BALB/c and C57BL/6 mice,were epicutaneously sensitized with ovalbumin on atopic dermatitis(AD)-like skin lesions,followed by intragastric challenge to induce IgE-mediated food allergy.Allergic outcomes were measured as clinical signs,specific antibodies and cytokines,and immune cell subpopulations,as well as changes in intestinal barrier function and gut microbiota.Results showed that both strains of mice exhibited typical food-allergic symptoms with a Th2-skewed response.The C57BL/6 mice,rather than the BALB/c mice,were fitter for establishing an epicutaneously sensitized model of food allergy since a stronger Th2-biased response and severer disruptions in the intestinal barrier and gut homeostasis were observed.This study provides knowledge for selecting an appropriate mouse model to study food-allergic responses associated with AD-like skin lesions and highlights the role of genetic variations in the immune mechanism underlying pathogenesis of food allergy.

Transgenic dry eye mouse models: powerful tools to study dry eye disease

Dry eye disease(DED) is one of the most common chronic multifactorial ocular surface diseases with high prevalence and complex pathogenesis. DED results in several ocular discomforts, vision fluctuation, and even potential damage of the ocular surface, bringing heavy burdens both on individuals and the society. The pathology of DED consists of tear film hyperosmolarity and immune responses on the ocular surface. Mice are widely used for developing models that simulate human DED features for investigating its pathogenesis and treatment. DED can be classified into aqueous-deficiency dry eye(ADDE) and evaporative dry eye(EDE). ADDE can be further divided into Sj?gren syndrome dry eye(SSDE) and non-Sj?gren syndrome dry eye(NSSDE). SSDE mouse models include natural strains, typified by non-obese diabetic(NOD) mice, and genetically engineered ones, like Aire-/-and Id3 knockout mice. Intrinsic EDE mainly refers to meibomian gland dysfunction(MGD). Eda-/-Tabby, Sod1-/-, Elovl1-/-are the most common transgenic MGD mouse models. Transgenic mouse models provide useful tools for studying the pathogenesis of DED and evaluating its novel therapies. This review compares the major transgenic dry eye mouse models and discusses their applications in DED research.

Adipose tissue-derived stem cells ameliorates dermal fibrosis in mouse models of scleroderma

Objective: To investigate the therapeutic potential of adipose-derived stem cells(ADSCs) for limited cutaneous scleroderma(LS) in mouse models,Methods: ADSCs were isolated from pathogen-free female C57BL/6 mice and LS was induced in wild type(WT) C57BL/6 mice via daily injection of bleomycin(0.1 m L x 300 μg/m L) for 4 weeks; then the ADSCs were subcutaneously injected into the dorsal area in the model treatment group,and 100 μL of phosphate buffered saline(PBS) solution was injected into the same site in the model control group,Green fluorescent protein(GFP) was used to track the cells using an in vivo imaging system on days 7,14,21 and 28 after transplantation,All mice were sacrificed and histologic analyses were performed after 4 weeks,and the skin thickness,collagen deposition and the total content of hydroxyproline were evaluated,Additionally,immunohistochemistry were performed to compare the tissue expression and distribution of TGF-β1 and VEGF between the ADSCs treatment group and the treatment control group,Results: WT C57BL/6 LS mouse model were successfully established and GFP in vivo fluorescence imaging showed that the translated ADSCs survived at the local for at least 4 weeks,Compared with the control group,the ADSCs treatment group significantly attenuated bleomycin-induced dermal fibrosis,reduced the skin thickness and the total content of hydroxyproline(P<0.05),The ADSCs treatment group displayed significantly lower levels of TGF-β1 and higher levels of VEGF than the control group(P<0.05),Conclusions: ADSCs may provide a feasible and practical treatment for autoimmune diseases such as LS and ameliorate dermal fibrosis.

The role of mouse models in colorectal cancer research—The need and the importance of the orthotopic models

Colorectal cancer is a worldwide health burden,with high incidence and mortality,especially in the advanced stages of the disease.Preclinical models are very important and valuable to discover and validate early and specific biomarkers as well as new therapeutic targets.In order to accomplish that,the animal models must replicate the clinical evolution of the disease in all of its phases.In this article,we review the existent mouse models,with their strengths and weaknesses in the replication of human cancer disease progression,with major focus on orthotopic models.

PTPN22 and islet-specific autoimmunity:What have the mouse models taught us?

An allelic variant of the protein tyrosin phosphatase non-receptor 22(PTPN22) gene, PTPN22 R620 W, constitutes the strongest non-HLA genetic risk factor for the development of type 1 diabetes(T1D). A numberstudies using mouse models have addressed how PTPN22 predisposes to T1D. PTPN22 downmodulation, overexpression or expression of the variant gene in genetically manipulated mice has generated controversial results. These discrepancies probably derive from the fact that PTPN22 has differential effects on innate and adaptive immune responses. Moreover, the effects of PTPN22 are dependent on other genetic variables. Here we discuss these findings and try to explain the discrepancies. Exploring the mechanism by which PTPN22 contributes to islet-specific autoimmunity could help us understand its role in T1D pathogenesis and exploit it as a potential therapeutic target to prevent the disease.

Evodiamine derivatives improve cognitive abilities in APP^(swe)/PS1^(ΔE9) transgenic mouse models of Alzheimer's disease

Background: Alzheimer's disease(AD) is a complex neurodegenerative disease. Due to the complexity of its molecular pathogenesis and the interaction of the numerous factors involved, the etiology and pathogenesis of AD have not been fully elucidated. Therefore, effective treatment for AD remains to be developed. Evodiamine, a quinolone alkaloid, has been found to improve learning and memory ability to in the APP^(swe)/PS1^(ΔE9) mouse model of dementia. However, the cytotoxicity and physicochemical properties of evodiamine have limited its use in the treatment of AD.Methods: Evodiamine and its derivatives were effectively synthesized by EDCImediated condensation at room temperature. These target compounds contained 1 thio-and 21 oxo-evodiamine derivatives with different substituted groups. The cytotoxicity of evodiamine and its derivatives and the neuroprotective effects of the evodiamine derivatives against H_2O_2-induced cell loss in SH-SY5 Y cells were investigated using the WST-8 assay. The Morris water-maze test was used to detect the effect of evodiamine and its derivatives on improving learning and memory in APP^(swe)/PS1^(ΔE9) mice.Results: In this study, a series of oxo-and thio-evodiamine derivatives was synthesized. Several derivatives showed lower cytotoxicity and stronger neuroprotective effects than evodiamine and elicited enhanced cognitive improvement, especially in the test of spatial memory in APP^(swe)/PS1^(ΔE9) mice.Conclusion: Our study provides insights for developing novel evodiamine derivatives for chemical intervention and treatment of AD.

Mouse models of epithelial ovarian cancer for preclinical studies

Epithelial ovarian cancer(EOC) is the leading cause of gynecological cancer-related mortality in the developed world. EOC is a heterogeneous disease represented by several histological and molecular subtypes. Therefore, exploration of relevant preclinical animal models that consider the heterogenic nature of EOC is of great importance for the development of novel therapeutic strategies that can be translated clinically to combat this devastating disease. In this review, we discuss recent progress in the development of preclinical mouse models for EOC study as well as their advantages and limitations.

Role of cancer stem cell ecosystem on breast cancer metastasis and related mouse models

Breast cancer metastasis is responsible for most breast cancer-related deaths and is influenced by many factors within the tumor ecosystem,including tumor cells and microenvironment.Breast cancer stem cells(BCSCs)constitute a small population of cancer cells with unique characteristics,including their capacity for self-renewal and differentiation.Studies have shown that BCSCs not only drive tumorigenesis but also play a crucial role in promoting metastasis in breast cancer.The tumor microenvironment(TME),composed of stromal cells,immune cells,blood vessel cells,fibroblasts,and microbes in proximity to cancer cells,is increasingly recognized for its crosstalk with BCSCs and role in BCSC survival,growth,and dissemination,thereby influencing metastatic ability.Hence,a thorough understanding of BCSCs and the TME is critical for unraveling the mechanisms underlying breast cancer metastasis.In this review,we summarize current knowledge on the roles of BCSCs and the TME in breast cancer metastasis,as well as the underlying regulatory mechanisms.Furthermore,we provide an overview of relevant mouse models used to study breast cancer metastasis,as well as treatment strategies and clinical trials addressing BCSC-TME interactions during metastasis.Overall,this study provides valuable insights for the development of effective therapeutic strategies to reduce breast cancer metastasis.

Establishment of head and neck squamous cell carcinoma mouse models for cetuximab resistance and sensitivity

Aim:Acquired resistance to the targeted agent cetuximab poses a significant challenge in finding effective anti-cancer treatments for head and neck squamous cell carcinoma(HNSCC).To accurately study novel combination treatments,suitable preclinical mouse models for cetuximab resistance are key yet currently limited.This study aimed to optimize an acquired cetuximab-resistant mouse model,with preservation of the innate immunity,ensuring intact antibody-dependent cellular cytotoxicity(ADCC)functionality.Methods:Cetuximab-sensitive and acquired-resistant HNSCC cell lines,generated in vitro,were subcutaneously engrafted in Rag2 knock-out(KO),BALB/c Nude and CB17 Scid mice with/without Matrigel or Geltrex.Once tumor growth was established,mice were intraperitoneally injected twice a week with cetuximab for a maximum of 3 weeks.In addition,immunohistochemistry was used to evaluate the tumor and its microenvironment.Results:Despite several adjustments in cell number,cell lines and the addition of Matrigel,Rag2 KO and BALB/C Nude mice proved to be unsuitable for xenografting our HNSCC cell lines.Durable tumor growth of resistant SC263-R cells could be induced in CB17 Scid mice.However,these cells had lost their resistance phenotype in vivo.Immunohistochemistry revealed a high infiltration of macrophages in cetuximab-treated SC263-R tumors.FaDu-S and FaDu-R cells successfully engrafted into CB17 Scid mice and maintained their sensitivity/resistance to cetuximab.Conclusion:We have established in vivo HNSCC mouse models with intact ADCC functionality for cetuximab resistance and sensitivity using the FaDu-R and FaDu-S cell lines,respectively.These models serve as valuable tools for investigating cetuximab resistance mechanisms and exploring novel drug combination strategies.

Generation and characterization of Men1 mutant mouse models for studying MEN1 disease

Patients with multiple endocrine neoplasia type 1(MEN1)mutations are predisposed to MEN1 syndrome affecting various endocrine cell lineages.Following its identification in the late 1990s,laboratories around the world,including our own,used gene-targeting approaches in murine models to study the MEN1 gene and its related diseases.Subsequently,this field of research witnessed an upsurge in the use of Men1 mutant mouse models to dissect MEN1 functions.These studies led to unraveling the natural history of MEN disease,and highlighted cellular and molecular mechanisms underlying the development of the disease.In this review,we present the currently available data concerning the generation and characterization of Men1 mutant mouse models in connection with MEN1 syndrome.

Establishment of pseudovirus infection mouse models for in vivo pharmacodynamics evaluation of filovirus entry inhibitors

Filoviruses cause severe and fatal viral hemorrhagic fever in humans. Filovirus research has been extensive since the 2014 Ebola outbreak. Due to their high pathogenicity and mortality, live filoviruses require Biosafety Level-4(BSL-4) facilities, which have restricted the development of anti-filovirus vaccines and drugs.An HIV-based pseudovirus cell infection assay is widely used for viral entry studies in BSL-2 conditions. Here,we successfully constructed nine in vitro pseudo-filovirus models covering all filovirus genera and three in vivo pseudo-filovirus-infection mouse models using Ebola virus, Marburg virus, and Lloviu virus as representative viruses. The pseudo-filovirus-infected mice showed visualizing bioluminescence in a dose-dependent manner. A bioluminescence peak in mice was reached on day 5 post-infection for Ebola virus and Marburg virus and on day4 post-infection for Lloviu virus. Two known filovirus entry inhibitors, clomiphene and toremiphene, were used to validate the model. Collectively, our study shows that all genera of filoviruses can be well-pseudotyped and are infectious in vitro. The pseudo-filovirus-infection mouse models can be used for in vivo activity evaluation of anti-filovirus drugs. This sequential in vitro and in vivo evaluation system of filovirus entry inhibitors provides a secure and efficient platform for screening and assessing anti-filovirus agents in BSL-2 facilities.

Identification in Chinese patients with GLIALCAM mutations of megalencephalic leukoencephalopathy with subcortical cysts and brain pathological study on Glialcam knock-in mouse models

Background Megalencephalic leukoencephalopathy with subcortical cysts(MLC)is a rare neurological degenerative disorder caused by the mutations of MLC1 or GLIALCAM with autosomal recessive or autosomal dominant inheritance and a different prognosis,characterized by macrocephaly,delayed motor and cognitive development,and bilateral abnormal signals in cerebral white matter(WM)with or without cysts on magnetic resonance imaging(MRI).This study aimed to reveal the clinical and genetic features of MLC patients with GLIALCAM mutations and to explore the brain pathological characteristics and prognosis of mouse models with different modes of inheritance.Methods Clinical information and peripheral venous blood were collected from six families.Genetic analysis was performed by Sanger sequencing of GLIALCAM.Glialcam^(Arg92Trp/+)and Glialcam^(Lys68Met/Thr132Asn)mouse models were generated based on mutations from patients(c.274C>T(p.Arg92Trp)(c.203A>T(p.Lys68Met),and c.395C>A(p.Thr132Asn))).Brain pathologies of the mouse models at different time points were analyzed.Results Six patients were clinically diagnosed with MLC.Of the six patients,five(Pt1-Pt5)presented with a heterozygous mutation in GLIALCAM(c.274C>T(p.Arg92Trp)or c.275G>C(p.Arg92Pro))and were diagnosed with MLC2B;the remaining patient(Pt6)with two compound heterozygous mutations in GLIALCAM(c.203A>T(p.Lys68Met)and c.395C>A(p.Thr132Asn))was diagnosed with MLC2A.The mutation c.275C>G(p.Arg92Pro)has not been reported before.Clinical manifestations of the patient with MLC2A(Pt6)progressed with regression,whereas the course of the five MLC2B patients remained stable or improved.The Glialcam^(Arg92Trp/+)and Glialcam^(Lys68Met/Thr132Asn)mouse models showed vacuolization in the anterior commissural WM at 1 month of age and vacuolization in the cerebellar WM at 3 and 6 months,respectively.At 9 months,the vacuolization of the GlialcamiLys68Met/Thr132Asn mouse model was heavier than that of the Glialcam^(Arg92Trp/+)mouse model.Decreased expression of Glialcam in Glialcam^(Arg92Trp/+)and Glialcam^(Lys68Met/Thr132Asn)mice may contribute to the vacuolization.Conclusions Clinical and genetic characterization of patients with MLC and GLIALCAM mutations revealed a novel mutation,expanding the spectrum of GLIALCAM mutations.The first Glialcam mouse model with autosomal recessive inheritance and a new Glialcam mouse model with autosomal dominant inheritance were generated.The two mouse models with different modes of inheritance showed different degrees of brain pathological features,which were consistent with the patients'phenotype and further confirmed the pathogenicity of the corresponding mutations.

The tumor suppressor kinase LKB1:lessons from mouse models

Mutations in the tumor suppressor gene LKB1 are important in hereditary Peutz–Jeghers syndrome,as well as in sporadic cancers including lung and cervical cancer.LKB1 is a kinase-activating kinase,and a number of LKB1-dependent phosphorylation cascades regulate fundamental cellular and organismal processes in at least metabolism,polarity,cytoskeleton organization,and proliferation.Conditional targeting approaches are beginning to demonstrate the relevance and specificity of these signaling pathways in development and homeostasis of multiple organs.More than one of the pathways also appear to contribute to tumor growth following Lkb1 deficiencies based on a number of mouse tumor models.Lkb1-dependent activation of AMPK and subsequent inactivation of mammalian target of rapamycin signaling are implicated in several of the models,and other less well characterized pathways are also involved.Conditional targeting studies of Lkb1 also point an important role of LKB1 in epithelial–mesenchymal interactions,significantly expanding knowledge on the relevance of LKB1 in human disease.

Characteristics of traumatic brain injury models:from macroscopic blood flow changes to microscopic mitochondrial changes

Controlled cortical impingement is a widely accepted method to induce traumatic brain injury to establish a traumatic brain injury animal model.A strike depth of 1 mm at a certain speed is recommended for a moderate brain injury and a depth of>2 mm is used to induce severe brain injury.However,the different effects and underlying mechanisms of these two model types have not been proven.This study investigated the changes in cerebral blood flow,differences in the degree of cortical damage,and differences in motor function under different injury parameters of 1 and 2 mm at injury speeds of 3,4,and 5 m/s.We also explored the functional changes and mitochondrial damage between the 1 and 2 mm groups in the acute(7 days)and chronic phases(30 days).The results showed that the cerebral blood flow in the injured area of the 1 mm group was significantly increased,and swelling and bulging of brain tissue,increased vascular permeability,and large-scale exudation occurred.In the 2 mm group,the main pathological changes were decreased cerebral blood flow,brain tissue loss,and cerebral vasospasm occlusion in the injured area.Substantial motor and cognitive impairments were found on day 7 after injury in the 2 mm group;at 30 days after injury,the motor function of the 2 mm group mice recovered significantly while cognitive impairment persisted.Transcriptome sequencing showed that compared with the 1 mm group,the 2 mm group expressed more ferroptosis-related genes.Morphological changes of mitochondria in the two groups on days 7 and 30 using transmission electron microscopy revealed that on day 7,the mitochondria in both groups shrank and the vacuoles became larger;on day 30,the mitochondria in the 1 mm group became larger,and the vacuoles in the 2 mm group remained enlarged.By analyzing the proportion of mitochondrial subgroups in different groups,we found that the model mice had different patterns of mitochondrial composition at different time periods,suggesting that the difference in the degree of damage among traumatic brain injury groups may reflect the mitochondrial changes.Taken together,differences in mitochondrial morphology and function between the 1 and 2 mm groups provide a new direction for the accurate classification of traumatic brain injury.Our results provide reliable data support and evaluation methods for promoting the establishment of standard mouse controlled cortical impingement model guidelines.

Anti-infection effects of heparin on SARS-CoV-2 in a diabetic mouse model

Severe acute respiratory syndrome coronavirus 2(SARSCo V-2)infection can result in more severe syndromes and poorer outcomes in patients with diabetes and obesity.However,the precise mechanisms responsible for the combined impact of coronavirus disease 2019(COVID-19)and diabetes have not yet been elucidated,and effective treatment options for SARS-Co V-2-infected diabetic patients remain limited.To investigate the disease pathogenesis,K18-h ACE2 transgenic(h ACE2^(Tg))mice with a leptin receptor deficiency(h ACE2-Lepr^(-/-))and high-fat diet(h ACE2-HFD)background were generated.The two mouse models were intranasally infected with a 5×10^(5) median tissue culture infectious dose(TCID_(50))of SARSCo V-2,with serum and lung tissue samples collected at 3days post-infection.The h ACE2-Lepr^(-/-)mice were then administered a combination of low-molecular-weight heparin(LMWH)(1 mg/kg or 5 mg/kg)and insulin via subcutaneous injection prior to intranasal infection with1×10^(4) TCID_(50)of SARS-Co V-2.Daily drug administration continued until the euthanasia of the mice.Analyses of viral RNA loads,histopathological changes in lung tissue,and inflammation factors were conducted.Results demonstrated similar SARS-Co V-2 susceptibility in h ACE2^(Tg)mice under both lean(chow diet)and obese(HFD)conditions.However,compared to the h ACE2-Lepr^(+/+)mice,h ACE2-Lepr^(-/-)mice exhibited more severe lung injury,enhanced expression of inflammatory cytokines and hypoxia-inducible factor-1α(HIF-1α),and increased apoptosis.Moreover,combined LMWH and insulin treatment effectively reduced disease progression and severity,attenuated lung pathological changes,and mitigated inflammatory responses.In conclusion,preexisting diabetes can lead to more severe lung damage upon SARS-Co V-2 infection,and LMWH may be a valuable therapeutic approach for managing COVID-19patients with diabetes.

One extraction tool for in vitro-in vivo extrapolation?SPME-based metabolomics of in vitro 2D,3D,and in vivo mouse melanoma models

Solid phase microextraction(SPME)in combination with high-resolution mass spectrometry was employed for the determination of metabolomic profile of mouse melanoma growth within in vitro 2D,in vitro 3D,and in vivo models.Such multi-model approach had never been investigated before.Due to the low-invasiveness of SPME,it was possible to perform time-course analysis,which allowed building time profile of biochemical reactions in the studied material.Such approach does not require the multiplication of samples as subsequent analyses are performed from the very same cell culture or from the same individual.SPME already reduces the number of animals required for experiment;therefore,it is with good concordance with the 3Rs rule(replacement,reduction,and refinement).Among tested models,the largest number of compounds was found within the in vitro 2D cell culture model,while in vivo and in vitro 3D models had the lowest number of detected compounds.These results may be connected with a higher metabolic rate,as well as lower integrity of the in vitro 2D model compared to the in vitro 3D model resulting in a lower number of compounds released into medium in the latter model.In terms of in vitro-in vivo extrapolation,the in vitro 2D model performed more similar to in vivo model compared to in vitro 3D model;however,it might have been due to the fact that only compounds secreted to medium were investigated.Thus,in further experiments to obtain full metabolome information,the intraspheroidal assessment or spheroid dissociation would be necessary.

LRRK2 mutant knock-in mouse models: therapeutic relevance in Parkinson’s disease

Mutations in the leucine-rich repeat kinase 2 gene (LRRK2) are one of the most frequent genetic causes of both familial and sporadic Parkinson’s disease (PD). Mounting evidence has demonstrated pathological similarities between LRRK2-associated PD (LRRK2-PD) and sporadic PD, suggesting that LRRK2 is a potential disease modulator and a thera-peutic target in PD. LRRK2 mutant knock-in (KI) mouse models display subtle alterations in pathological aspects that mirror early-stage PD, including increased susceptibility of nigrostriatal neurotransmission, development of motor and non-motor symptoms, mitochondrial and autophagy-lysosomal defects and synucleinopathies. This review provides a rationale for the use of LRRK2 KI mice to investigate the LRRK2-mediated pathogenesis of PD and implications from current findings from different LRRK2 KI mouse models, and ultimately discusses the therapeutic potentials against LRRK2-associated pathologies in PD.

Polymerase chain reaction-based assays facilitate the breeding and study of mouse models of Klinefelter syndrome

Klinefelter syndrome(KS)is one of the most frequent genetic abnormalities and the leading genetic cause of nonobstructive azoospermia.The breeding and study of KS mouse models are essential to advancing our knowledge of the underlying pathological mechanism.Karyotyping and fluorescence in situ hybridization are reliable methods for identifying chromosomal contents.However,technical issues associated with these methods can decrease the efficiency of breeding KS mouse models and limit studies that require rapid identification of target mice.To overcome these limitations,we developed three polymerase chain reaction-based assays to measure specific genetic information,including presence or absence of the sex determining region of chromosome Y(Sry),copy number of amelogenin,X-linked(Amelx),and inactive X specific transcripts(Xist)levels.Through a combined analysis of the assay results,we can infer the karyotype of target mice.We confirmed the utility of our assays with the successful generation of KS mouse models.Our assays are rapid,inexpensive,high capacity,easy to perform,and only require small sample amounts.Therefore,they facilitate the breeding and study of KS mouse models and help advance our knowledge of the pathological mechanism underlying KS.

Mouse models to study genes involved in hematological malignancies

Hematological malignancies,including leukemia and lymphoma,consist a group of highly heterogeneous neoplasms characterized by numerous genetic lesions specific for the type of the disease.In order to understand,the role of a particular alteration in the development of a malignancy functional studies have to be carried out in vitro,in cell lines derived from primary cancer cells.Further efforts to understand the mechanisms underlying blood disorders including malignant transformation and progression relies on model organism research.Numerous transgenic mouse models,carrying human oncogenes have been generated resembling distinct types of hematological disorders.Recent technological advances revolutionized the generation of animal models making it much easier,faster,and precise.The introduction of the CRISPR-Cas9 technology allows for rapid generation of novel knockout or transgenic animals,and the development of conditional site-and time-specific Cre-Lox gene targeting technology,allows studying the function of genes which are relevant to normal hematopoiesis and development of hematological malignancies,but lethal when knocked out in embryonic cells.Besides the studies on gene function,mouse models of human leukemia allow for discovery and testing of novel antileukemic drugs.These new technologies are deepening our understanding of disease pathophysiology and treatment resistance,as well as are leading to novel therapeutic strategies for improved outcomes in patients.

Cancer models in preclinical research:A chronicle review of advancement in effective cancer research

Cancer is a major stress for public well-being and is the most dreadful disease.The models used in the discovery of cancer treatment are continuously changing and extending toward advanced preclinical studies.Cancer models are either naturally existing or artificially prepared experimental systems that show similar features with human tumors though the heterogeneous nature of the tumor is very familiar.The choice of the most fitting model to best reflect the given tumor system is one of the real difficulties for cancer examination.Therefore,vast studies have been conducted on the cancer models for developing a better understanding of cancer invasion,progression,and early detection.These models give an insight into cancer etiology,molecular basis,host tumor interaction,the role of microenvironment,and tumor heterogeneity in tumor metastasis.These models are also used to predict novel can-cer markers,targeted therapies,and are extremely helpful in drug development.In this review,the potential of cancer models to be used as a platform for drug screening and therapeutic discoveries are highlighted.Although none of the cancer models is regarded as ideal because each is associated with essential caveats that restraint its application yet by bridging the gap between preliminary cancer research and transla-tional medicine.However,they promise a brighter future for cancer treatment.