Patient-derived xenograft model in colorectal cancer basic and translational research

Colorectal cancer(CRC)is one of the most popular malignancies globally,with 930000 deaths in 2020.The evaluation of CRC-related pathogenesis and the discovery of po-tential therapeutic targets will be meaningful and helpful for improving CRC treat-ment.With huge efforts made in past decades,the systematic treatment regimens have been applied to improve the prognosis of CRC patients.However,the sensitivity of CRC to chemotherapy and targeted therapy is different from person to person,which is an important cause of treatment failure.The emergence of patient-derived xenograft(PDX)models shows great potential to alleviate the straits.PDX models possess similar genetic and pathological characteristics as the features of primary tu-mors.Moreover,PDX has the ability to mimic the tumor microenvironment of the original tumor.Thus,the PDX model is an important tool to screen precise drugs for individualized treatment,seek predictive biomarkers for prognosis supervision,and evaluate the unknown mechanism in basic research.This paper reviews the recent advances in constructed methods and applications of the CRC PDX model,aiming to provide new knowledge for CRC basic research and therapeutics.

Spontaneous xenogeneic GvHD in Wilms'tumor Patient-Derived xenograft models and potential solutions

Severely immunocompromised NOD.Cg-PrkdcIl2rg(NOG)mice are among the ideal animal recipients for generation of human cancer models.Transplantation of human solid tumors having abundant tumor-i nfiltrating lymphocytes(TILs)can induce xenogeneic graft-versus-host disease(xGvHD)following engraftment and expansion of the TILs inside the animal body.Wilms’tumor(WT)has not been recognized as a lymphocyte-predominant tumor.However,3 consecutive generations of NOG mice bearing WT patient-derived xenografts(PDX)xenotransplanted from a single donor showed different degrees of inflammatory symptoms after transplantation before any therapeutic intervention.In the initial generation,dermatitis,auto-amputation of digits,weight loss,lymphadenopathy,hepatitis,and interstitial pneumonitis were observed.Despite antibiotic treatment,no response was noticed,and thus the animals were prematurely euthanized(day 47 posttransplantation).Laboratory and histopathologic evaluations revealed lymphoid infiltrates positively immunostained with anti-human CD3 and CD8 antibodies in the xenografts and primary tumor,whereas no microbial infection or lymphoproliferative disorder was found.Mice of the next generation that lived longer(91 days)developed sclerotic skin changes and more severe pneumonitis.Cutaneous symptoms were milder in the last generation.The xenografts of the last 2 generations also contained TILs,and lacked lymphoproliferative transformation.The systemic immunoinflammatory syndrome in the absence of microbial infection and posttransplant lymphoproliferative disorder was suggestive of xGvHD.While there are few reports of xGvHD in severely immunodeficient mice xenotransplanted from lymphodominant tumor xenografts,this report for the first time documented serial xGvHD in consecutive passages of WT PDX-bearing models and discussed potential solutions to prevent such an undesired complication.

Translational pancreatic cancer research:a comparative study on patient-derived xenograft models

AIM To assess the viability of orthotopic and heterotopic patient-derived pancreatic cancer xenografts implanted into nude mice.METHODS This study presents a prospective experimental analytical follow-up of the development of tumours in mice upon implantation of human pancreatic adenocarcinoma samples. Specimens were obtained surgically from patients with a pathological diagnosis of pancreatic adenocarcinoma. Tumour samples from pancreatic cancer patients were transplanted into nude mice in three different locations(intraperitoneal, subcutaneous and pancreatic). Histological analysis(haematoxylin-eosin and Masson's trichrome staining) and immunohistochemical assessment of apoptosis(TUNEL), proliferation(Ki-67), angiogenesis(CD31) and fibrogenesis(α-SMA) were performed. When a tumour xenograft reached the target size, it was reimplanted in a new nude mouse. Three sequential tumour xenograft generations were generated(F1, F2 and F3).RESULTS The overall tumour engraftment rate was 61.1%. The subcutaneous model was most effective in terms of tissue growth(69.9%), followed by intraperitoneal(57.6%) and pancreatic(55%) models. Tumour development was faster in the subcutaneous model(17.7 ± 2.6 wk) compared with the pancreatic(23.1 ± 2.3 wk) and intraperitoneal(25.0 ± 2.7 wk) models(P = 0.064). There was a progressive increase in the tumour engraftment rate over successive generations for all three models(F1 28.1% vs F2 71.4% vs F3 80.9%, P < 0.001). There were no significant differences in tumour xenograft differentiation and cell proliferation between human samples and the three experimental models among the sequential generations of tumour xenografts. However, a progressive decrease in fibrosis, fibrogenesis, tumour vascularisation and apoptosis was observed in the three experimental models compared with the human samples. All three pancreatic patient-derived xenograft models presented similar histological and immunohistochemical characteristics.CONCLUSION In our experience, the faster development andgreatest number of viable xenografts could make the subcutaneous model the best option for experimentation in pancreatic cancer.

Specific bone region localization of osteolytic versus osteoblastic lesions in a patient-derived xenograft model of bone metastatic prostate cancer

Objective:Bone metastasis occurs in up to 90%of men with advanced prostate cancer and leads to fractures,severe pain and therapy-resistance.Bone metastases induce a spectrum of types of bone lesions which can respond differently to therapy even within individual prostate cancer patients.Thus,the special environment of the bone makes the disease more complicated and incurable.A model in which bone lesions are reproducibly induced that mirrors the complexity seen in patients would be invaluable for pre-clinical testing of novel treatments.The microstructural changes in the femurs of mice implanted with PCSD1,a new patient-derived xenograft from a surgical prostate cancer bone metastasis specimen,were determined.Methods:Quantitative micro-computed tomography(micro-CT)and histological analyses were performed to evaluate the effects of direct injection of PCSD1 cells or media alone(Control)into the right femurs of Rag2
/
gc
/
male mice.Results:Bone lesions formed only in femurs of mice injected with PCSD1 cells.Bone volume(BV)was significantly decreased at the proximal and distal ends of the femurs(p<0.01)whereas BV(p<0.05)and bone shaft diameter(p<0.01)were significantly increased along the femur shaft.Conclusion:PCSD1 cells reproducibly induced bone loss leading to osteolytic lesions at the ends of the femur,and,in contrast,induced aberrant bone formation leading to osteoblastic lesions along the femur shaft.Therefore,the interaction of PCSD1 cells with different bone region-specific microenvironments specified the type of bone lesion.Our approach can be used to determine if different bone regions support more therapy resistant tumor growth,thus,requiring novel treatments.

Application of patient-derived tumor models in anticancer drug development and individualized medicine

Malignant tumor is the second leading cause of death due to its high incidence, lack of effective treatment and poor prognosis. The evaluation of anticancer drugs used to based on NCI-60 cell line models, but the limited heterogeneity and the divorce from clinical practice of models lead to extremely low success rate of novel anticancer drugs during clinical trials (less than 10%). In recent years, because of the high heterogeneity and human derived tumor matrix, patient-derived tumor models have been gradually applied to the preclinical evaluation of various antitumor drugs, which shows certain advantages in predicting the clinical efficacy of antitumor drugs. Optimize the drug combination through patient-derived tumor models to achieve individualized medicine has gradually become an indispensable strategy in clinical cancer therapy. The current review summarized the development of patient-derived tumor models, characterized the application, advantages and challenges of them in preclinical antitumor drug evaluation and clinical precise medicine, which will provide a scientific basis and novel insights for further basic research, drug development and clinical application.

SPA: A Quantitation Strategy for MS Data in Patient-derived Xenograft Models

With the development of mass spectrometry(MS)-based proteomics technologies,patient-derived xenograft(PDX),which is generated from the primary tumor of a patient,is widely used for the proteome-wide analysis of cancer mechanism and biomarker identification of a drug.However,the proteomics data interpretation is still challenging due to complex data deconvolution from the PDX sample that is a cross-species mixture of human cancerous tissues and immunodeficient mouse tissues.In this study,by using the lab-assembled mixture of human and mouse cells with different mixing ratios as a benchmark,we developed and evaluated a new method,SPA(shared peptide allocation),for protein quantitation by considering the unique and shared peptides of both species.The results showed that SPA could provide more convenient and accurate protein quantitation in human–mouse mixed samples.Further validation on a pair of gastric PDX samples(one bearing FGFR2 amplification while the other one not)showed that our new method not only significantly improved the overall protein identification,but also detected the differential phosphorylation of FGFR2 and its downstream mediators(such as RAS and ERK)exclusively.The tool pdx SPA is freely available at https://github.com/LiLab-Proteomics/pdx SPA.

Generation and application of patient-derived xenograft models in pancreatic cancer research

Objective:Pancreatic ductal adenocarcinoma cancer(PDAC)is one of the leading causes of cancer-related death worldwide.Hence,the development of effective anti-PDAC therapies is urgently required.Patient-derived xenograft(PDX)models are useful models for developing anti-cancer therapies and screening drugs for pre&sion medicine.This review aimed to provide an updated summary of using PDX models in PDAC.Data sources:The author retrieved information from the PubMed database up to June 2019 using various combinations of search terms,including PDAC,pancreatic carcinoma,pancreatic cancer,patient-derived xenografts or PDX,and patient-derived tumor xenografts or PDTX.Study selection:Original articles and review articles relevant to the review's theme were selected.Results:PDX models are better than cell line-derived xenograft and other models.PDX models consistently demonstrate retained tumor morphology and genetic stability,are benefi&al in cancer research,could enhance drug discovery and oncologic mechanism development of PDAC,allow an improved understanding of human cancer cell biology,and help guide personalized treatmem.Conclusions:In this review,we outline the status and application of PDX models in both basic and pre-clinical pancreatic cancer researches.PDX model is one of the most appropriate pre-clinical tools that can improve the prognosis of patients with pancreatic cancer in the future.

Integrating of lipophilic platinum(IV) prodrug into liposomes for cancer therapy on patient-derived xenograft model

Platinum-based anticancer agents such as cisplatin and its analogues are widely used for treating multiple cancers. However, due to the inferior water-solubility, chemoresistance and consequent adverse side effects, their clinical applications are limited. Herein, choles Pt(IV), a lipophilic platinum(IV) prodrug was synthesized for manufacture of Choles Pt(IV)-Liposomes aiming to resolve the predefined obstacles encountered by platinum drugs. Following systematic screening, Choles Pt(IV)-Liposomes showed a small particle size(105.6 nm), the rapid release of platinum(Pt) ions, and notable apoptosis of cancer cells.In addition, according to the fluidity and safety results of animal experiments in mice, Choles Pt(IV)-Liposomes also showed better therapeutic effect, which significantly inhibited the growth of patientderived xenograft tumors of hepatocellular carcinoma with an inhibition ratio of 80.7%, and effectively alleviated the drug toxicity brought by traditional platinum drugs. Overall, this study provides a promising route to enhance the therapeutic efficiency of platinum drugs in cancer treatment.

Development of gemcitabine-resistant patient-derived xenograft models of pancreatic ductal adenocarcinoma

Aim:Gemcitabine is a frontline agent for locally-advanced and metastatic pancreatic ductal adenocarcinoma(PDAC),but neither gemcitabine alone nor in combination produces durable remissions of this tumor type.We developed three PDAC patient-derived xenograft(PDX)models with gemcitabine resistance(gemR)acquired in vivo,with which to identify mechanisms of resistance relevant to drug exposure in vivo and to evaluate novel therapies.Methods:Mice bearing independently-derived PDXs received 100 mg/kg gemcitabine once or twice weekly.Tumors initially responded,but regrew on treatment and were designated gemR.We used immunohistochemistry to compare expression of proteins previously associated with gemcitabine resistance[ribonucleotide reductase subunit M1(RRM1),RRM2,human concentrative nucleoside transporter 1(hCNT1),human equilibrative nucleoside transporter 1(hENT1),cytidine deaminase(CDA),and deoxycytidine kinase(dCK)]in gemR and respective gemcitabine-naïve parental tumors.Results:Parental and gemR tumors did not differ in tumor cell morphology,amount of tumor-associated stroma,or expression of stem cell markers.No consistent pattern of expression of the six gemR marker proteins was observed among the models.Increases in RRM1 and CDA were consistent with in vitro-derived gemR models.However,rather than the expected decreases of hCNT1,hENT1,and dCK,gemR tumors expressed no change in or higher levels of these gemR marker proteins than parental tumors.Conclusion:These models are the first PDAC PDX models with gemcitabine resistance acquired in vivo.The data indicate that mechanisms identified in models with resistance acquired in vitro are unlikely to be the predominant mechanisms when resistance is acquired in vivo.Ongoing work focuses on characterizing unidentified mechanisms of gemR and on identifying agents with anti-tumor efficacy in these gemR models。

Patient-derived xenograft models for oncology drug discovery

The success of targeted therapies for cancer patients rests on three major components:the right target(s),the right drug and drug combination,and the right patient population.Although much progress has been made in understanding the mechanism of disease and in refi ning pharmaceutical properties of therapeutic agents,the attrition rates between target discovery and drug marketing approval have been high,especially in oncology.One of the main reasons underlying this undesirable statistics is believed to be the lack of predictive power of the model systems used in the preclinical setting.Several strategies have been employed with the aim of improving the predictive value of the preclinical studies,such as incorporating genomic profi ling and molecular segmentation into model selection,and enhancing the development and application of patient-derived xenograft models even during early stage of drug discovery.This brief review will summarize some of the recent concept and practice in incorporating patient-derived models into all stages of drug discovery process,from target to clinical development.

Patient-derived non-small cell lung cancer xenograft mirrors complex tumor heterogeneity

Objective:Patient-derived xenograft(PDX)models have shown great promise in preclinical and translational applications,but their consistency with primary tumors in phenotypic,genetic,and pharmacodynamic heterogeneity has not been well-studied.This study aimed to establish a PDX repository for non-small cell lung cancer(NSCLC)and to further elucidate whether it could preserve the heterogeneity within and between tumors in patients.Methods:A total of 75 surgically resected NSCLC specimens were implanted into immunodeficient NOD/SCID mice.Based on the successful establishment of the NSCLC PDX model,we compared the expressions of vimentin,Ki67,EGFR,and PD-L1 proteins between cancer tissues and PDX models using hematoxylin and eosin staining and immunohistochemical staining.In addition,we detected whole gene expression profiling between primary tumors and PDX generations.We also performed whole exome sequencing(WES)analysis in 17 first generation xenografts to further assess whether PDXs retained the patient heterogeneities.Finally,paclitaxel,cisplatin,doxorubicin,atezolizumab,afatininb,and AZD4547 were used to evaluate the responses of PDX models to the standard-of-care agents.Results:A large collection of serially transplantable PDX models for NSCLC were successfully developed.The histology and pathological immunohistochemistry of PDX xenografts were consistent with the patients’tumor samples.WES and RNA-seq further confirmed that PDX accurately replicated the molecular heterogeneities of primary tumors.Similar to clinical patients,PDX models responded differentially to the standard-of-care treatment,including chemo-,targeted-and immuno-therapeutics.Conclusions:Our established PDX models of NSCLC faithfully reproduced the molecular,histopathological,and therapeutic characteristics,as well as the corresponding tumor heterogeneities,which provides a clinically relevant platform for drug screening,biomarker discovery,and translational research.

Molecular phenotypes reveal heterogeneous engraftments of patient-derived hepatocellular carcinoma xenografts

Objective:Patient-derived xenograft(PDX)models provide a promising preclinical platform for hepatocellular carcinoma(HCC).However,the molecular features associated with successful engraftment of PDX models have not been revealed.Methods:HCC tumor samples from 76 patients were implanted in immunodeficient mice.The molecular expression was evaluated by immunohistochemistry.Patient and tumor characteristics as well as tumor molecular expressions were compared for PDX engraftment using the Chi-square test.The independent prediction parameters were identified by logistic regression analyses.Results:The engraftment rate for PDX models from patients with HCC was 39.47%(30/76).Tumors from younger patients and patients with elevated preoperative alpha-fetoprotein level had higher engraftment rates.Tumors with poor differentiation and vascular invasion were related to engraftment success.The positive expression of CK19,CD133,glypican-3(GPC3),and Ki67 in tumor samples was associated with engraftment success.Logistic regression analyses indicated that GPC3 and Ki67 were two of the strongest predictors of PDX engraftment.Tumors with GPC3/Ki67 phenotypes showed heterogeneous engraftment rates,with 71.9%in GPC3^(+)/Ki67^(+)tumors,30.8%in GPC3^(-)/Ki67^(+)tumors,15.0%in GPC3^(+)/Ki67^(-)tumors,and 0 in GPC3^(-)/Ki67^(-)tumors.Conclusions:Successful engraftment of HCC PDXs was significantly related to molecular features.Tumors with the GPC3+/Ki67+phenotype were the most likely to successfully establish HCC PDXs.

Advantages and limitations in the establishment and utilization of patient-derived xenografts in gastric cancer

Owing to the high genetic heterogeneity of tumors, small number of therapeutic strategies available, and frequent presentation of drug resistance, the prognosis for patients with advanced gastric cancer(AGC) are unsatisfactory. The utility of traditional cancer cell lines in translational research is limited by their poor correspondence to the genomic alterations and expression profiles that occur in actual patient tumors. In the last decade, increasing attention has been given to patient-derived tumor xenografts(PDTXs), which can faithfully recapitulate the histopathology, molecular characteristics, and therapeutic responses of the patient's tumor. However, the widespread development and utilization of PDTXs is restricted by factors such as the timeframe of establishment, lymphoma transformation during passaging, the immunodeficient microenvironment, and pharmacokinetic differences between mice and humans. In this review, we summarize the establishment and characterization of PDTX models for gastric cancer(GC). We then weigh the advantages and limitations of PDTXs when used to evaluate novel compounds, identify effective biomarkers, demonstrate resistance mechanisms, and predict clinical outcomes.

Murine models based on acute myeloid leukemia-initiating stem cells xenografting

Acute myeloid leukemia(AML) is an aggressive malignant disease defined by abnormal expansion of myeloid blasts. Despite recent advances in understanding AML pathogenesis and identifying their molecular subtypes based on somatic mutations, AML is still characterized by poor outcomes, with a 5-year survival rate of only 30%-40%, the majority of the patients dying due to AML relapse. Leukemia stem cells(LSC) are considered to be at the root of chemotherapeutic resistance and AML relapse. Although numerous studies have tried to better characterize LSCs in terms of surface and molecular markers, a specific marker of LSC has not been found, and still the most universally accepted phenotypic signature remains the surface antigens CD34+CD38- that is shared with normal hematopoietic stem cells. Animal models provides the means to investigate the factors responsible for leukemic transformation, the intrinsic differences between secondary post-myeloproliferative neoplasm AML and de novo AML, especially the signaling pathways involved in inflammation and hematopoiesis. However, AML proved to be one of the hematological malignancies that is difficult to engraft even in the most immunodeficient mice strains, and numerous ongoing attempts are focused to develop "humanized mice" that can support the engraftment of LSC. This present review is aiming to in-troduce the field of AML pathogenesis and the concept of LSC, to present the current knowledge on leukemic blasts surface markers and recent attempts to develop best AML animal models.

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.

Establishment,functional and genetic characterization of three novel patient-derived rectal cancer cell lines

AIM To establish patient-individual tumor models of rectal cancer for analyses of novel biomarkers, individual response prediction and individual therapy regimens.METHODS Establishment of cell lines was conducted by direct in vitro culturing and in vivo xenografting with subsequent in vitro culturing. Cell lines were in-depth characterized concerning morphological features, invasive and migratory behavior, phenotype, molecular profile including mutational analysis, protein expression, and confirmation of origin by DNA fingerprint. Assessment of chemosensitivity towards an extensive range of current chemotherapeutic drugs and of radiosensitivity was performed including analysis of a combined radioand chemotherapeutic treatment. In addition, glucose metabolism was assessed with 18 F-fluorodeoxyglucose(FDG) and proliferation with 18 F-fluorothymidine.RESULTS We describe the establishment of ultra-low passage rectal cancer cell lines of three patients suffering from rectal cancer. Two cell lines(HROC126, HROC284 Met) were established directly from tumor specimens while HROC239 T0 M1 was established subsequent to xenografting of the tumor. Molecular analysis classified all three cell lines as CIMP-0/non-MSI-H(sporadic standard) type. Mutational analysis revealed following mutational profiles: HROC126: APC^(wt), TP53^(wt), KRAS^(wt), BRAF^(wt), PTEN^(wt); HROC239 T0 M1: APC^(mut), P53^(wt), KRAS^(mut), BRAF^(wt), PTEN^(mut) and HROC284 Met: APC^(wt), P53^(mut), KRAS^(mut), BRAF^(wt), PTEN^(mut). All cell lines could be characterized as epithelial(EpCAM+) tumor cells with equivalent morphologic features and comparable growth kinetics. The cell lines displayed a heterogeneous response toward chemotherapy, radiotherapy and their combined application. HROC126 showed a highly radio-resistant phenotype and HROC284 Met was more susceptible to a combined radiochemotherapy than HROC126 and HROC239 T0 M1. Analysis of 18 F-FDG uptake displayed a markedly reduced FDG uptake of all three cell lines after combined radiochemotherapy. CONCLUSION These newly established and in-depth characterized ultra-low passage rectal cancer cell lines provide a useful instrument for analysis of biological characteristics of rectal cancer.

Combination Therapy of Capecitabine with Cyclophosphamide as a Second-Line Treatment after Failure of Paclitaxel plus Bevacizumab Treatment in a Human Triple Negative Breast Cancer Xenograft Model

We examined the antitumor efficacy of the capecitabine (CAPE) plus cyclophosphamide (CPA) combination as a 2nd-line therapy after paclitaxel (PTX) plus bevacizumab (BEV) treatment in a xenograft model of human triple negative breast cancer (TNBC) cell line, MX-1. After tumor growth was confirmed, PTX (20 mg/kg;i.v.) + BEV (5 mg/kg;i.p.) treatment was started (Day 1). Each agent was administered once a week for 5 weeks and tumor regression was observed for at least the first 3 weeks. For 2nd-line treatment, we selected mice in which the tumor volume had increased from day 29 to day 36 and was within 130 - 250 mm3 on day 36. After randomization of mice selected on day 36, CPA (10 mg/kg;p.o.) and CAPE (539 mg/kg;p.o.) were administered daily for 14 days (days 36 - 49), followed by cessation of the drugs for 1 week. The tumor growth on day 57 was significantly suppressed in the CPA, CAPE and CAPE + CPA groups as compared with the control group (p < 0.05). Furthermore, the antitumor activity on day 57 of CAPE + CPA was significantly stronger than that of CPA or CAPE alone (p < 0.05). The thymidine phosphorylase (TP) level in tumor tissue was evaluated by immunohistochemistry on day 50, and was significantly higher in the CPA group than those in the control group (p < 0.05). Upregulation of TP in tumor tissues by CPA treatment would increase the 5-FU level in tumor tissues treated with CAPE. This would explain the possible mechanism that made CAPE + CPA superior to CAPE alone in the 2nd-line treatment. Our preclinical results suggest that the CAPE + CPA combination therapy may be effective as 2nd-line therapy after disease progression in PTX + BEV 1st-line treatment for TNBC patients.

Establishment of various biliary tract carcinoma cell lines and xenograft models for appropriate preclinical studies

We recently reported several driver genes of biliary tract carcinoma(BTC) that are known to play important roles in oncogenesis and disease progression. Although the need for developing novel therapeutic strategies is increasing, there are very few BTC cell lines and xenograft models currently available for conducting preclinical studies. Using a total of 88 surgical BTC specimens and 536 immunodeficient mice, 28 xenograft models and 13 new BTC cell lines, including subtypes, were established. Some of our cell lines were found to be resistant to gemcitabine, which is currently the first choice of treatment, thereby allowing highly practical preclinical studies to be conducted. Using the aforementioned cell lines and xenograft models and a clinical pathological database of patients undergoing BTC resection, we can establish a preclinical study system and appropriate parameters for drug efficacy studies to explore new biomarkers for practical applications in the future studies.

头颈部恶性肿瘤研究模型的演化

恶性肿瘤发生发展的机制探索以及抗癌药物治疗疗效的评估均有赖于各种体内与体外研究模型的建立。近几十年间,随着生物医学技术的快速发展,恶性肿瘤的体内外研究模型也发生了巨大的变化。基因检测技术从单基因到多基因的进展促进了生物信息学飞速发展和恶性肿瘤概念的转变;体外细胞研究模型从单层的二维培养、原代培养向立体的三维构型发展,从而更好地重现肿瘤组织的细胞间交互作用与功能;体内动物研究模型由传统的致癌物诱导、细胞或组织形成移植瘤逐渐演变为基因编辑的动物模型或人源性肿瘤异种移植模型,从而可以针对性地研究相关基因在肿瘤发生发展中的作用;传统的临床研究也从简单的临床回顾性研究更多地向前瞻性研究转变,Ⅰ期/Ⅱ期/Ⅲ期临床研究,研究者发起的临床研究以及真实世界临床研究,这些研究为临床研究增添了活力。目前恶性肿瘤研究模型存在的主要不足包括模型的单一性、对肿瘤微环境的模拟不足、动物肿瘤模型与人类肿瘤差异性,以及缺乏对个性化医疗的考量。未来仍需要进一步研发和优化研究模型,并更有效地将不同模型整合起来,形成一个优化的整体实验模型系统。本文将系统回顾恶性肿瘤研究模型的演化并对相关模型进行阐述,为科研工作者进行恶性肿瘤的研究提供合理的研究模型。

Patient-derived xenograft platform of OSCC： a renewable human bio-bank for preclinical cancer research and a new co-clinical model for treatment optimization

Advances in next-generation sequencing and bioinformatics have begun to reveal the complex genetic landscape in human cancer genomes, including oral squamous cell carcinoma （OSCC）. Sophisticated preclinical models that fully represent intra- and inter-tumoral heterogeneity are required to understand the molecular diversity of cancer and achieve the goal of personalized therapies. Patient-derived xenograft （PDX） models generated from human tumor samples that can retain the histological and genetic features of their donor tumors have been shown to be the preferred preclinical tool in translational cancer research compared with other conventional preclinical models. Specifically, genetically well-defined PDX models can be applied to accelerate targeted antitumor drug development and biomarker discovery. Recently, we have successfully established and characterized an OSCC PDX panel as part of our tumor bio-bank for translational cancer research. In this paper, we discuss the establishment, characterization, and preclinical applications of the PDX models. In particular, we focus on the classification and applications of the PDX models based on validated annotations, including clinicopathological features, genomic profiles, and pharmacological testing information. We also explore the translational value of this well-annotated PDX panel in the development of co-clinical trials for patient stratification and treatment optimization in the near future. Although various limitations still exist, this preclinical approach should be further tested and improved.