Characterization of the Tumor-Microenvironment in Patient-Derived Cervix Xenografts (OCICx)

Clinical relevance and therapeutic predictive ability of hypoxia biomarkers in head and neck cancer tumour models

Tumour hypoxia promotes poor patient outcomes, with particularly strong evidence for head and neck squamous cell carcinoma (HNSCC). To effectively target hypoxia, therapies require selection biomarkers and preclinical models that can accurately model tumour hypoxia. We established 20 patient-derived xenograft (PDX) and cell line-derived xenograft (CDX) models of HNSCC that we characterised for their fidelity to represent clinical HNSCC in gene expression, hypoxia status and proliferation and that were evaluated for their sensitivity to hypoxia-activated prodrugs (HAPs). PDX models showed greater fidelity in gene expression to clinical HNSCC than cell lines, as did CDX models relative to their paired cell lines. PDX models were significantly more hypoxic than CDX models, as assessed by hypoxia gene signatures and pimonidazole immunohistochemistry, and showed similar hypoxia gene expression to clinical HNSCC tumours. Hypoxia or proliferation status alone could not determine HAP sensitivity across our 20 HNSCC and two non-HNSCC tumour models by either tumour growth inhibition or killing of hypoxia cells in an ex vivo clonogenic assay. In summary, our tumour models provide clinically relevant HNSCC models that are suitable for evaluating hypoxia-targeting therapies; however, additional biomarkers to hypoxia are required to accurately predict drug sensitivity.

An orthotopic prostate cancer model for new treatment development using syngeneic or patient-derived tumors

BACKGROUND

There are limited preclinical orthotopic prostate cancer models due to the technical complexity of surgical engraftment and tracking the tumor growth in the mouse prostate gland. Orthotopic xenografts recapitulate the tumor microenvironment, tumor stromal interactions, and clinical behavior to a greater extent than xenografts grown at subcutaneous or intramuscular sites.

METHODS

This study describes a novel micro-surgical technique for orthotopically implanting intact tumors pieces from cell line derived (transgenic adenocarcinoma mouse prostate [TRAMP]-C2) or patient derived (neuroendocrine prostate cancer [NEPC]) tumors in the mouse prostate gland and monitoring tumor growth using magnetic resonance (MR) imaging.

RESULTS

The TRAMP-C2 tumors grew rapidly to a predetermined endpoint size of 10 mm within 3 weeks, whereas the NEPC tumors grew at a slower rate over 7 weeks. The tumors were readily detected by MR and confidently identified when they were approximately 2-3 mm in size. The tumors were less well-defined on CT. The TRAMP-C2 tumors were characterized by amorphous sheets of poorly differentiated cells similar to a high-grade prostatic adenocarcinoma and frequent macroscopic peritoneal and lymph node metastases. In contrast, the NEPC's displayed a neuroendocrine morphology with polygonal cells arranged in nests and solid sheets and high count. There was a local invasion of the bladder and other adjacent tissues but no identifiable metastases. The TRAMP-C2 tumors were more hypoxic than the NEPC tumors.

CONCLUSIONS

This novel preclinical orthotopic prostate cancer mouse model is suitable for either syngeneic or patient derived tumors and will be effective in developing and advancing the current selection of treatments for patients with prostate cancer.

Creation and Validation of Patient-Derived Cancer Model Using Peritoneal and Pleural Effusion in Patients with Advanced Ovarian Cancer: An Early Experience

Background: The application of personalized cancer treatment based on genetic information and surgical samples has begun in the field of cancer medicine. However, a biopsy may be painful for patients with advanced diseases that do not qualify for surgical resection. Patient-derived xenografts (PDXs) are cancer models in which patient samples are transplanted into immunodeficient mice. PDXs are expected to be useful for personalized medicine. The aim of this study was to establish a PDX from body fluid (PDX-BF), such as peritoneal and pleural effusion samples, to provide personalized medicine without surgery. Methods: PDXs-BF were created from patients with ovarian cancer who had positive cytology findings based on peritoneal and pleural effusion samples. PDXs were also prepared from each primary tumor. The pathological findings based on immunohistochemistry were compared between the primary tumor, PDX, and PDX-BF. Further, genomic profiles and gene expression were evaluated using DNA and RNA sequencing to compare primary tumors, PDXs, and PDX-BF. Results: Among the 15 patients, PDX-BF was established for 8 patients (5 high-grade serous carcinoma, 1 carcinosarcoma, 1 low-grade serous carcinoma, and 1 clear cell carcinoma); the success rate was 53%. Histologically, PDXs-BF have features similar to those of primary tumors and PDXs. In particular, PDXs-BF had similar gene mutations and expression patterns to primary tumors and PDXs. Conclusions: PDX-BF reproduced primary tumors in terms of pathological features and genomic profiles, including gene mutation and expression. Thus, PDX-BF may be a potential alternative to surgical resection for patients with advanced disease.

FBXW7-loss Sensitizes Cells to ATR Inhibition Through Induced Mitotic Catastrophe

FBXW7 is a commonly mutated tumor suppressor gene that functions to regulate numerous oncogenes involved in cell-cycle regulation. Genome-wide CRISPR fitness screens identified a signature of DNA repair and DNA damage response genes as required for the growth of FBXW7-knockout cells. Guided by these findings, we show that FBXW7-mutant cells have high levels of replication stress, which results in a genotype-specific vulnerability to inhibition of the ATR signaling pathway, as these mutant cells become heavily reliant on a robust S-G2 checkpoint. ATR inhibition induces an accelerated S-phase, leading to mitotic catastrophe and cell death caused by the high replication stress present in FBXW7-/- cells. In addition, we provide evidence in cell and organoid studies, and mining of publicly available high-throughput drug screening efforts, that this genotype-specific vulnerability extends to multiple types of cancer, providing a rational means of identifying responsive patients for targeted therapy.

SIGNIFICANCE

We have elucidated the synthetic lethal interactions between FBXW7 mutation and DNA damage response genes, and highlighted the potential of ATR inhibitors as targeted therapies for cancers harboring FBXW7 alterations.

Establishment of a high-fidelity patient-derived xenograft model for cervical cancer enables the evaluation of patient's response to conventional and novel therapies

BACKGROUND

Recurrent or metastatic cervical cancer (r/m CC) often has poor prognosis owing to its limited treatment options. The development of novel therapeutic strategies has been hindered by the lack of preclinical models that accurately reflect the biological and genomic heterogeneity of cervical cancer (CC). Herein, we aimed to establish a large patient-derived xenograft (PDX) biobank for CC, evaluate the consistency of the biologic indicators between PDX and primary tumor tissues of patients, and explore its utility for assessing patient's response to conventional and novel therapies.

METHODS

Sixty-nine fresh CC tumor tissues were implanted directly into immunodeficient mice to establish PDX models. The concordance of the PDX models with their corresponding primary tumors (PTs) was compared based on the clinical pathological features, protein biomarker levels, and genomic features through hematoxylin & eosin staining, immunohistochemistry, and whole exome sequencing, respectively. Moreover, the clinical information of CC patients, RNA transcriptome and immune phenotyping of primary tumors were integrated to identify the potential parameters that could affect the success of xenograft engraftment. Subsequently, PDX model was evaluated for its capacity to mirror patient's response to chemotherapy. Finally, PDX model and PDX-derived organoid (PDXO) were utilized to evaluate the therapeutic efficacy of neratinib and adoptive cell therapy (ACT) combination strategy for CC patients with human epidermal growth factor receptor 2 (HER2) mutation.

RESULTS

We established a PDX biobank for CC with a success rate of 63.8% (44/69). The primary features of established PDX tumors, including clinicopathological features, the expression levels of protein biomarkers including Ki67, α-smooth muscle actin, and p16, and genomics, were highly consistent with their PTs. Furthermore, xenograft engraftment was likely influenced by the primary tumor size, the presence of follicular helper T cells and the expression of cell adhesion-related genes in primary tumor tissue. The CC derived PDX models were capable of recapitulating the patient's response to chemotherapy. In a PDX model, a novel therapeutic strategy, the combination of ACT and neratinib, was shown to effectively inhibit the growth of PDX tumors derived from CC patients with HER2-mutation.

CONCLUSIONS

We established by far the largest PDX biobank with a high engraftment rate for CC that preserves the histopathological and genetic characteristics of patient's biopsy samples, recapitulates patient's response to conventional therapy, and is capable of evaluating the efficacy of novel therapeutic modalities for CC.

Application status and future prospects of the PDX model in lung cancer

Lung cancer is one of the most prevalent, fatal, and highly heterogeneous diseases that, seriously threaten human health. Lung cancer is primarily caused by the aberrant expression of multiple genes in the cells. Lung cancer treatment options include surgery, radiation, chemotherapy, targeted therapy, and immunotherapy. In recent decades, significant progress has been made in developing therapeutic agents for lung cancer as well as a biomarker for its early diagnosis. Nonetheless, the alternative applications of traditional pre-clinical models (cell line models) for diagnosis and prognosis prediction are constrained by several factors, including the lack of microenvironment components necessary to affect cancer biology and drug response, and the differences between laboratory and clinical results. The leading reason is that substantial shifts accrued to cell biological behaviors, such as cell proliferative, metastatic, invasive, and gene expression capabilities of different cancer cells after decades of growing indefinitely in vitro. Moreover, the introduction of individualized treatment has prompted the development of appropriate experimental models. In recent years, preclinical research on lung cancer has primarily relied on the patient-derived tumor xenograft (PDX) model. The PDX provides stable models with recapitulate characteristics of the parental tumor such as the histopathology and genetic blueprint. Additionally, PDXs offer valuable models for efficacy screening of new cancer drugs, thus, advancing the understanding of tumor biology. Concurrently, with the heightened interest in the PDX models, potential shortcomings have gradually emerged. This review summarizes the significant advantages of PDXs over the previous models, their benefits, potential future uses and interrogating open issues.

Establishment and genetically characterization of patient-derived xenograft models of cervical cancer

Purpose

Patient-derived xenograft (PDX) models were established to reproduce the clinical situation of original cancers and have increasingly been applied to preclinical cancer research. Our study was designed to establish and genetically characterize cervical cancer PDX models.

Methods

A total of 91 fresh fragments obtained from 22 surgically resected cervical cancer tissues were subcutaneously engrafted into female NOD-SCID mice. Hematoxylin and eosin (H&E) staining was performed to assess whether the established PDX models conserved the histological features of original patient cervical cancer tissues. Moreover, a Venn diagram was applied to display the overlap of all mutations detected in whole-genome sequencing (WGS) data from patient original cervical cancer (F0) and F2-, F3-PDX models. The whole exome sequencing (WES) and the “maftools” package were applied to determine the somatic mutations among primary cervical cancers and the established PDX models.

Results

Our study successfully developed a panel of cervical cancer PDX models and the latency time of cervical cancer PDX model establishment was variable with a progressive decrease as the passage number increased, with a mean time to initial growth of 94.71 days in F1 engraftment to 40.65 days in F3 engraftment. Moreover, the cervical cancer PDX models preserved the histological features of their original cervical cancer. WGS revealed that the genome of original cervical cancer was preserved with high fidelity in cervical cancer PDX models throughout the xenografting and passaging process. Furthermore, WES demonstrated that the cervical cancer PDX models maintained the majority somatic mutations of original cervical cancer, of which the KMT2D, LRP1B, NAV3, TP53, FAT1, MKI67 and PKHD1L1 genes were identified as the most frequently mutated genes.

Conclusions

The cervical cancer PDX models preserved the histologic and genetic characteristics of their original cervical cancer, which helped to gain a deeper insight into the genetic alterations and lay a foundation for further investigation of the molecular targeted therapy of cervical cancer.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12920-022-01342-5.

Validation of a Patient-Derived Xenograft Model for Cervical Cancer Based on Genomic and Phenotypic Characterization

Simple Summary

The rate of total tumor engraftment of patient-derived xenografts is 50% in cervical cancer. These cancers retain their histopathological characteristics. The gene mutations and expression patterns associated with carcinogenesis and infiltration and the expression levels of genes in extracellular vesicles released from the tumors are similar between patient-derived xenograft models and primary tumors. Patient-derived xenograft models of cervical cancer could be potentially useful tools for translational research.

Abstract

Patient-derived xenograft (PDX) models are useful tools for preclinical drug evaluation, biomarker identification, and personalized medicine strategies, and can be developed by the heterotopic or orthotopic grafting of surgically resected tumors into immunodeficient mice. We report the PDX models of cervical cancer and demonstrate the similarities among original and different generations of PDX tumors. Fresh tumor tissues collected from 22 patients with primary cervical cancer were engrafted subcutaneously into NOD.CB17-PrkdcSCID/J mice. Histological and immunohistochemical analyses were performed to compare primary and different generations of PDX tumors. DNA and RNA sequencing were performed to verify the similarity between the genetic profiles of primary and PDX tumors. Total RNA in extracellular vesicles (EVs) released from primary and PDX tumors was also quantified to evaluate gene expression. The total tumor engraftment rate was 50%. Histologically, no major differences were observed between the original and PDX tumors. Most of the gene mutations and expression patterns related to carcinogenesis and infiltration were similar between the primary tumor and xenograft. Most genes associated with carcinogenesis and infiltration showed similar expression levels in the primary tumor and xenograft EVs. Therefore, compared with primary tumors, PDX models could be potentially more useful for translational research.

Patient-Derived Xenografts of High-Grade Serous Ovarian Cancer Subtype as a Powerful Tool in Pre-Clinical Research

(1) Background. PDX models have become the preferred tool in research laboratories seeking to improve development and pre-clinical testing of new drugs. PDXs have been shown to capture the cellular and molecular characteristics of human tumors better than simpler cell line-based models. More recently, however, hints that PDXs may change their characteristics over time have begun to emerge, emphasizing the need for comprehensive analysis of PDX evolution. (2) Methods. We established a panel of high-grade serous ovarian carcinoma (HGSOC) PDXs and developed and validated a 300-SNP signature that can be successfully utilized to assess genetic drift across PDX passages and detect PDX contamination with lymphoproliferative tissues. In addition, we performed a detailed histological characterization and functional assessment of multiple PDX passages. (3) Results. Our data show that the PDXs remain largely stable throughout propagation, with marginal genetic drift at the time of PDX initiation and adaptation to mouse host. Importantly, our PDX lines retained the major histological characteristics of the original patients' tumors even after multiple passages in mice, demonstrating a strong concordance with the clinical responses of their corresponding patients. (4) Conclusions. Our data underline the value of defined HGSOC PDXs as a pre-clinical tumor model.

Incorporating cross-voxel exchange into the analysis of dynamic contrast-enhanced imaging data: theory, simulations and experimental results

Predictions of tumour perfusion are key determinants of drug delivery and responsiveness to therapy. Pharmacokinetic models allow for the estimation of perfusion properties of tumour tissues but many assume no dispersion associated with tracer transport away from the capillaries and through the tissue. At the level of a voxel, this translates to assuming no cross-voxel tracer exchange, often leading to the misinterpretation of derived perfusion parameters. Tofts model (TM), a compartmental model widely used in oncology, also makes this assumption. A more realistic description is required to quantify kinetic properties of tracers, such as convection and diffusion. We propose a Cross-Voxel Exchange Model (CVXM) for analysing cross-voxel tracer kinetics.In silicodatasets quantifying the roles of convection and diffusion in tracer transport (which TM ignores) were employed to investigate the interpretation of Tofts' perfusion parameters compared to CVXM. TM returned inaccurate values ofKtransandvewhere diffusive and convective mechanisms are pronounced (up to 20% and 300% error respectively). A mathematical equation, developed in this work, predicts and gives the correct physiological interpretation of Tofts've.Finally, transport parameters were derived from dynamic contrast enhanced-magnetic resonance imaging of a TS-415 human cervical carcinoma xenograft by using TM and CVXM. The latter deduced lower values ofKtransandvecompared to TM (lower by up to 63% and 76% respectively). It also allowed the detection of a diffusive flux (mean diffusivity 155μm²s^-1) in the tumour tissue, as well as an increased convective flow at the periphery (mean velocity 2.3μm s^-1detected). The results serve as a proof of concept establishing the feasibility of using CVXM for accurately determining transport metrics that characterize the exchange of tracer between voxels. CVXM needs to be investigated further as its parameters can be linked to the tumour microenvironment properties (permeability, pressure…), potentially leading to enhanced personalized treatment planning.

Patient-Derived Xenograft Models in Cervical Cancer: A Systematic Review

BACKGROUND

Patient-derived xenograft (PDX) models have been a focus of attention because they closely resemble the tumor features of patients and retain the molecular and histological features of diseases. They are promising tools for translational research. In the current systematic review, we identify publications on PDX models of cervical cancer (CC-PDX) with descriptions of main methodological characteristics and outcomes to identify the most suitable method for CC-PDX.

METHODS

We searched on PubMed to identify articles reporting CC-PDX. Briefly, the main inclusion criterion for papers was description of PDX created with fragments obtained from human cervical cancer specimens, and the exclusion criterion was the creation of xenograft with established cell lines.

RESULTS

After the search process, 10 studies were found and included in the systematic review. Among 98 donor patients, 61 CC-PDX were established, and the overall success rate was 62.2%. The success rate in each article ranged from 0% to 75% and was higher when using severe immunodeficient mice such as severe combined immunodeficient (SCID), nonobese diabetic (NOD) SCID, and NOD SCID gamma (NSG) mice than nude mice. Subrenal capsule implantation led to a higher engraftment rate than orthotopic and subcutaneous implantation. Fragments with a size of 1-3 mm3 were suitable for CC-PDX. No relationship was found between the engraftment rate and characteristics of the tumor and donor patient, including histology, staging, and metastasis. The latency period varied from 10 days to 12 months. Most studies showed a strong similarity in pathological and immunohistochemical features between the original tumor and the PDX model.

CONCLUSION

Severe immunodeficient mice and subrenal capsule implantation led to a higher engraftment rate; however, orthotopic and subcutaneous implantation were alternatives. When using nude mice, subrenal implantation may be better. Fragments with a size of 1-3 mm3 were suitable for CC-PDX. Few reports have been published about CC-PDX; the results were not confirmed because of the small sample size.

Alpelisib and radiotherapy treatment enhances Alisertib-mediated cervical cancer tumor killing

Human papilloma virus (HPV) is the main causative agent in cervical cancers. High-risk HPV cancers, including cervical cancer, are driven by major HPV oncogene, E6 and E7, which promote uncontrolled cell growth and genomic instability. We have previously shown that the presence of HPV E7 sensitizes cells to inhibition of aurora kinases (AURKs), which regulates the control of cell entry into and through mitosis. Such treatment is highly effective at eliminating early tumors and reducing large, late tumors. In addition, the presence of HPV oncogenes also sensitizes cells to inhibition of phosphoinositide 3-kinases (PI3Ks), a family of enzymes involved in cellular functions such as cell growth and proliferation. Using MLN8237 (Alisertib), an oral, selective inhibitor of AURKs, we investigated whether Alisertib treatment can improve tumor response when combined with either radiotherapy (RT) treatment or with a PI3K inhibitor, BYL719 (Alpelisib). Indeed, both RT and Alpelisib significantly improved Alisertib-mediated tumor killing, and the promising achieved results warrant further development of these combinations, and potentially translating them to the clinics.

The organoid: A research model for ovarian cancer

Epithelial ovarian cancer (EOC) is a heterogeneous disease with a variety of distinct clinical and molecular characteristics. The currently available and common research models for EOC include tumor cell lines and patient-derived xenografts. However, these models have certain shortcomings: establishing a cell line is time-consuming, loss of genetic traits after long-term culture is a possibility, and investment is required in terms of animal care facilities. Therefore, better research models are required. Organoid technology was originally developed from colorectal cancer. Tumor organoid is a three-dimensional culture system and can help accurately recapture the tumor phenotype from the original tumor. Tumor organoid systems can overcome the above-mentioned shortcomings of the currently available research models. The organoid model can be used for culturing ovarian cancer subtypes, screening drugs, assessing genomes, and establishing biobanks. However, the currently available organoid models can only culture one type of cells, epithelial cells. Therefore, an organoid-on-a-chip device can be developed in the future to provide a microenvironment for cell–cell, cell–matrix, and cell–media interactions. Thus, organoid models can be used in ovarian cancer research and can generate a simulated in vivo system, enabling studies on the heterogeneity of ovarian cancer.

Patient-Derived Xenograft and Organoid Models for Precision Medicine Targeting of the Tumour Microenvironment in Head and Neck Cancer

Patient survival from head and neck squamous cell carcinoma (HNSCC), the seventh most common cause of cancer, has not markedly improved in recent years despite the approval of targeted therapies and immunotherapy agents. Precision medicine approaches that seek to individualise therapy through the use of predictive biomarkers and stratification strategies offer opportunities to improve therapeutic success in HNSCC. To enable precision medicine of HNSCC, an understanding of the microenvironment that influences tumour growth and response to therapy is required alongside research tools that recapitulate the features of human tumours. In this review, we highlight the importance of the tumour microenvironment in HNSCC, with a focus on tumour hypoxia, and discuss the fidelity of patient-derived xenograft and organoids for modelling human HNSCC and response to therapy. We describe the benefits of patient-derived models over alternative preclinical models and their limitations in clinical relevance and how these impact their utility in precision medicine in HNSCC for the discovery of new therapeutic agents, as well as predictive biomarkers to identify patients' most likely to respond to therapy.

Hypoxia-responsive nanoparticle based drug delivery systems in cancer therapy: An up-to-date review

Hypoxia is a salient feature observed in most solid malignancies that holds a pivotal role in angiogenesis, metastasis and resistance to conventional cancer therapeutic approaches, and thus enables cancer progression. However, the typical characteristics of hypoxic cells such as low oxygen levels and highly bio-reductive environment can offer stimuli-responsive drug release to aid in tumor-specific chemo, radio, photodyanamic and sonodynamic therapies. This approach based on targeting the poorly oxygenated tumor habitats offers the prospective to overcome the difficulties that arises due to heterogenic nature of tumor and could be possibly used in the design of diagnostic as well as therapeutic nanocarriers for targeting various types of solid cancers. Consequently, hypoxia triggered nanoparticle based drug delivery systems is a rapidly progressing research area in developing effective strategies to combat drug-resistance in solid tumors. The present review presents the recent advances in the development of hypoxia-responsive nanovehicles for drug delivery to heterogeneous tumors. The initial sections of the article provides insights into the development of hypoxia in growing cancer and its role in disease progression. The current limitations and the future prospective of hypoxia-stimulated nanomachines for cancer treatment are also discussed.

The fidelity of cancer cells in PDX models: Characteristics, mechanism and clinical significance

Patient-derived xenograft (PDX) models are widely used as preclinical cancer models and are considered better than cell culture models in recapitulating the histological features, molecular characteristics and intratumoral heterogeneity (ITH) of human tumors. While the PDX model is commonly accepted for use in drug discovery and other translational studies, a growing body of evidence has suggested its limitations. Recently, the fidelity of cancer cells within a PDX has been questioned, which may impede the future application of these models. In this review, we will focus the variable phenotypes of xenograft tumors and the genomic instability and molecular inconsistency of PDX tumors after serial transplantation. Next, we will discuss the underlying mechanism of ITH and its clinical relevance. Stochastic selection bias in the sampling process and/or deterministic clonal dynamics due to murine selective pressure may have detrimental effects on the results of personalized medicine and drug screening studies. In addition, we aim to identify a possible solution for the issue of fidelity in current PDX models and to discuss emerging next-generation preclinical models.

Establishment of patient-derived xenograft model in ovarian cancer and its influence factors analysis

AIM

Patient-derived xenograft (PDX) model has been applied to the study of breast cancer, lung cancer, colon cancer and other cancers. However, its feasibility in ovarian cancer has not been understood. This study aimed to establish ovarian cancer PDX model and reveal its influence factors.

METHODS

In this study, 27 patients in Obstetrics and Gynecology Hospital affiliated to Fudan University from May 2015 to May 2016 were employed to explore the method of PDX model in ovarian cancer and verify its feasibility.

RESULTS

Finally, five cases of PDX models were successfully established, and the tumor formation rate (TFR) was 18.52%. In addition, immunohistochemistry and transcriptome sequencing analysis showed that tumor of PDX model have similar gene expression, gene splicing, gene fusion and single nucleotide polymorphisms with primary tumor (R² = 0.741). Furthermore, it was revealed that compared to epithelial ovarian cancer, the TFR of PDX models with nonepithelial ovarian cancer was higher, while other factors such as the initiation site of tumor, the degree of tumor malignancy, the stage of tumor, the type of tumor and the species of experimental animals were not associated with the TFR.

CONCLUSION

Ovarian cancer PDX model, as a new scientific research model, can better keep the biological characteristics of primary tumor, which has great research value in ovarian cancer.

A Tumor-on-a-Chip System with Bioprinted Blood and Lymphatic Vessel Pair

Current in vitro anti-tumor drug screening strategies are insufficiently portrayed lacking true perfusion and draining microcirculation systems, which may post significant limitation in reproducing the transport kinetics of cancer therapeutics explicitly. Herein, we report the fabrication of an improved tumor model consisting of bioprinted hollow blood vessel and lymphatic vessel pair, hosted in a three-dimensional (3D) tumor microenvironment-mimetic hydrogel matrix, termed as the tumor-on-a-chip with bioprinted blood and lymphatic vessel pair (TOC-BBL). The bioprinted blood vessel was perfusable channel with opening on both ends while the bioprinted lymphatic vessel was blinded on one end, both of which were embedded in a hydrogel tumor mass, with vessel permeability individually tunable through optimization of the composition of the bioinks. We demonstrated that systems with different combinations of these bioprinted blood/lymphatic vessels exhibited varying levels of diffusion profiles for biomolecules and anti-cancer drugs. Our TOC-BBL platform mimicking the natural pathway of drug-tumor interactions would have the drug introduced through the perfusable blood vessel, cross the vascular wall into the tumor tissue via diffusion, and eventually drained into the lymphatic vessel along with the carrier flow. Our results suggested that this unique in vitro tumor model containing the bioprinted blood/lymphatic vessel pair may have the capacity of simulating the complex transport mechanisms of certain pharmaceutical compounds inside the tumor microenvironment, potentially providing improved accuracy in future cancer drug screening.

Targeting CXCL12/CXCR4 and myeloid cells to improve the therapeutic ratio in patient-derived cervical cancer models treated with radio-chemotherapy

BACKGROUND

The CXCL12/CXCR4 chemokine pathway is involved in cervical cancer pathogenesis and radiation treatment (RT) response. We previously reported that radiochemotherapy (RTCT) and concurrent administration of the CXCR4 inhibitor plerixafor improved primary tumour response. The aims of this study were to determine optimal sequencing of RTCT and plerixafor, the mechanisms responsible for improved response and the effect of plerixafor on late intestinal toxicity.

METHODS

Orthotopic cervical cancer xenografts were treated with RTCT (30 Gy in 2 Gy fractions and cisplatin) with or without concurrent, adjuvant or continuous plerixafor. The endpoints were growth delay and molecular and immune cell changes at the end of treatment. Late intestinal toxicity was assessed by histologic examination of the rectum 90 days after a single 20 Gy fraction.

RESULTS

RTCT increased CXCL12/CXCR4 signalling and the intratumoral accumulation of myeloid cells; the addition of plerixafor mitigated these effects. All of the RTCT and plerixafor arms showed prolonged tumour growth delay compared to RTCT alone, with the adjuvant arm showing the greatest improvement. Plerixafor also reduced late intestinal toxicity.

CONCLUSION

Adding Plerixafor to RTCT blunts treatment-induced increases in CXCL12/CXCR4 signalling, improves primary tumour response and reduces intestinal side effects. This combination warrants testing in future clinical trials.

Impact of hydrostatic pressure on phase-change contrast agent activation by pulsed ultrasound

A phase-change contrast agent (PCCA) can be activated from a liquid (nanodroplet) state using pulsed ultrasound (US) energy to form a larger highly echogenic microbubble (MB). PCCA activation is dependent on the ambient pressure of the surrounding media, so any increase in hydrostatic pressure demands higher US energies to phase transition. In this paper, the authors explore this basic relationship as a potential direction for noninvasive pressure measurement and foundation of a unique technology the authors are developing termed tumor interstitial pressure estimation using ultrasound (TIPE-US). TIPE-US was developed using a programmable US research scanner. A custom scan sequence interleaved pulsed US transmissions for both PCCA activation and detection. An automated US pressure sweep was applied, and US images were acquired at each increment. Various hydrostatic pressures were applied to PCCA samples. Pressurized samples were imaged using the TIPE-US system. The activation threshold required to convert PCCA from the liquid to gaseous state was recorded for various US and PCCA conditions. Given the relationship between the hydrostatic pressure applied to the PCCA and US energy needed for activation, phase transition can be used as a surrogate of hydrostatic pressure. Consistent with theoretical predictions, the PCCA activation threshold was lowered with increasing sample temperature and by decreasing the frequency of US exposure, but it was not impacted by PCCA concentration.

Nitroimidazole derivative incorporated liposomes for hypoxia-triggered drug delivery and enhanced therapeutic efficacy in patient-derived tumor xenografts

Hypoxia is not merely a tumor microenvironment byproduct, but rather an active participant in tumor development, invasion, and metastasis. Hypoxia contributes to poor outcomes in tumor treatment and has currently emerged as an important therapeutic target. In this work, a facile hypoxia-responsive liposomal drug delivery system was developed by incorporating derivatized nitroimidazole into liposome membranes. Under hypoxic conditions, hypoxia-induced reductive metabolism of the nitroimidazole derivative facilitated disassembly of the liposomes for triggered drug release. The liposomes showed high sensitivity to hypoxia, even at the cellular level, and could release payload in an oxygen-dependent manner, leading to high cytotoxicity in hypoxic conditions. In vivo fluorescence imaging revealed that there was a selective release of the liposomes at the hypoxic tumor site. As a result, the liposomes exhibited enhanced therapeutic efficacy in treating a hypoxic tumor in both cell line-derived and clinically relevant patient-derived xenograft models. Thus, hypoxia-responsive liposomes are a promising drug delivery system for hypoxia targeted tumor therapy. STATEMENT OF SIGNIFICANCE: 1. A facile but smart hypoxia-responsive liposomal drug delivery system is developed by incorporating nitroimidazole derivative, one of representative hypoxia-responsive moieties, into phospholipid bilayer of the liposomes. 2. The liposomes show extremely high sensitivity to hypoxia and can selectively release payload in hypoxic cells and hypoxic tumor. 3. The liposomes show enhanced therapeutic efficacy not only in cell line-derived xenograft model but also in clinically relevant patient-derived xenograft model, indicating their promising prospect in clinical application.

A patient derived xenograft model of cervical cancer and cervical dysplasia

Aim

To develop a patient derived xenograft (PDX) model of cervical cancer and cervical dysplasia using the subrenal capsule.

Methods

Cervical cancer (12 Squamous Cell Carcinoma, 1 Adenocarcinoma, 1 Adenosquamous Carcinoma), 7 cervical dysplasia biopsy and normal cervical tissues were transplanted beneath the renal capsule of immunocompromised NOD/SCID/gamma mice. Resulting tumours were harvested and portions serially transplanted into new recipient mice for up to three in vivo passages. Parent and xenograft tumours were examined by immunohistochemistry for p16^INK41, HPV, and CD-45. Single cell suspensions of mixed mouse and human, or human only cell populations were also transplanted.

Results

The overall engraftment rate for the primary cervical cancer PDX model was 71.4 ±12.5% (n = 14). Tumours maintained morphological, histoarchitecture and immunohistochemical features of the parent tumour, and demonstrated invasiveness into local tissues. Single cell suspensions did not produce tumour growth in this model. Mean length of time (32.4 +/- 3.5 weeks) for the transplanted tissue to generate a tumour in the animal was similar between successive transplantations. Three of four xenografted cervical dysplasia tissues generated microscopic cystic structures resembling dysplastic cervical tissue. Normal cervical tissue (4 of 5 xenografted) also developed microscopic cervical tissue grafts.

Conclusion

The subrenal capsule can be used for a PDX model of human cervical cancer with a good engraftment rate and the ability to model in vivo characteristics of cervical cancer. For the first time we have demonstrated that cervical dysplasia and normal cervical tissue generated microscopic tissues in a PDX model.

Spatial frequency performance limitations of radiation dose optimization and beam positioning

The flexibility and sophistication of modern radiotherapy treatment planning and delivery methods have advanced techniques to improve the therapeutic ratio. Contemporary dose optimization and calculation algorithms facilitate radiotherapy plans which closely conform the three-dimensional dose distribution to the target, with beam shaping devices and image guided field targeting ensuring the fidelity and accuracy of treatment delivery. Ultimately, dose distribution conformity is limited by the maximum deliverable dose gradient; shallow dose gradients challenge techniques to deliver a tumoricidal radiation dose while minimizing dose to surrounding tissue. In this work, this 'dose delivery resolution' observation is rigorously formalized for a general dose delivery model based on the superposition of dose kernel primitives. It is proven that the spatial resolution of a delivered dose is bounded by the spatial frequency content of the underlying dose kernel, which in turn defines a lower bound in the minimization of a dose optimization objective function. In addition, it is shown that this optimization is penalized by a dose deposition strategy which enforces a constant relative phase (or constant spacing) between individual radiation beams. These results are further refined to provide a direct, analytic method to estimate the dose distribution arising from the minimization of such an optimization function. The efficacy of the overall framework is demonstrated on an image guided small animal microirradiator for a set of two-dimensional hypoxia guided dose prescriptions.

Increasing aggressiveness of patient-derived xenograft models of cervix carcinoma during serial transplantation

Four patient-derived xenograft (PDX) models (BK-12, ED-15, HL-16, LA-19) of carcinoma of the uterine cervix have been developed in our laboratory, and their stability during serial transplantation in vivo was investigated in this study. Two frozen cell stocks were established, one from xenografted tumors in passage 2 (early generation) and the other from xenografted tumors transplanted serially in mice for approximately two years (late generation), and the biology of late generation tumors was compared with that of early generation tumors. Late generation tumors showed higher incidence of lymph node metastases than early generation tumors in three models (ED-15, HL-16, LA-19), and the increased metastatic propensity was associated with increased tumor growth rate, increased microvascular density, and increased expression of angiogenesis-related and cancer stem cell-related genes. Furthermore, late generation tumors showed decreased fraction of pimonidazole-positive tissue (i.e., decreased fraction of hypoxic tissue) in two models (HL-16, LA-19) and decreased fraction of collagen-I-positive tissue (i.e., less extensive extracellular matrix) in two models (ED-15, HL-16). This study showed that serially transplanted PDXs may not necessarily mirror the donor patients’ diseases, and consequently, proper use of serially transplanted PDX models in translational cancer research requires careful molecular monitoring of the models.

Cancer initiating-cells are enriched in the CA9 positive fraction of primary cervix cancer xenografts

Numerous studies have suggested that Cancer Initiating Cells (CIC) can be identified/enriched in cell populations obtained from solid tumors based on the expression of cell surface marker proteins. We used early passage primary cervix cancer xenografts to sort cells based on the expression of the intrinsic hypoxia marker Carbonic Anhydrase 9 (CA9) and tested their cancer initiation potential by limiting dilution assay. We demonstrated that CICs are significantly enriched in the CA9⁺ fraction in 5/6 models studied. Analyses of the expression of the stem cell markers Oct4, Notch1, Sca-1 & Bmi1 showed a trend toward an increase in the CA9⁺ populations, albeit not significant. We present evidence that enhanced autophagy does not play a role in the enhanced growth of the CA9⁺ cells. Our study suggests a direct in vivo functional link between hypoxic cells and CICs in primary cervix cancer xenografts.

Targeting the CXCL12/CXCR4 pathway and myeloid cells to improve radiation treatment of locally advanced cervical cancer

Cervical cancer is the fourth most commonly diagnosed cancer and the fourth leading cause of cancer death in women worldwide. Approximately half of cervical cancer patients present with locally advanced disease, for which surgery is not an option. These cases are nonetheless potentially curable with radiotherapy and cisplatin chemotherapy. Unfortunately, some tumours are resistant to treatment, and lymph node and distant recurrences are major problems in patients with advanced disease at diagnosis. New targeted treatments that can overcome treatment resistance and reduce metastases are urgently needed. The CXCL12/CXCR4 chemokine pathway is ubiquitously expressed in many normal tissues and cancers, including cervical cancer. Emerging evidence indicates that it plays a central role in cervical cancer pathogenesis, malignant progression, the development of metastases and radiation treatment response. Pre-clinical studies of standard-of-care fractionated radiotherapy and concurrent weekly cisplatin plus the CXCR4 inhibitor Plerixafor (AMD3100) in patient-derived orthotopic cervical cancer xenografts have shown improved primary tumour response and reduced lymph node metastases with no increase in early or late side effects. These studies have pointed the way forward to future clinical trials of radiotherapy/cisplatin plus Plerixafor or other newly emerging CXCL12 or CXCR4 inhibitors in women with cervical cancer.

Tumor microenvironment determines response to a heat-activated thermosensitive liposome formulation of cisplatin in cervical carcinoma

Significant heterogeneity in the tumor microenvironment of human cervical cancer patients is known to challenge treatment outcomes in this population. The current standard of care for cervical cancer patients is radiation therapy and concurrent cisplatin (CDDP) chemotherapy. Yet this treatment strategy fails to control loco-regional disease in 10-30% of patients. In order to improve the loco-regional control rate, a thermosensitive liposome formulation of CDDP (HTLC) was developed to increase local concentrations of drug in response to mild hyperthermia (HT). The HTLC formulation in combination with local HT demonstrated a significant therapeutic advantage in comparison to free drug and Lipoplatin™ in ME-180 and SiHa xenograft models of human cervical cancer, as well as in four distinct cervical patient-derived xenograft models. Differential response to HTLC+HT treatment was observed between the ME-180 and SiHa tumor models. Tumor doubling time, in vitro cell sensitivity, and tumor drug accumulation were found to be non-predictive of treatment efficacy. Rather, tumor microenvironment parameters, in particular elevated levels of both tumor hypoxia and associated stromal content, were found to serve as the overriding factors that limit drug efficacy. The prognostic value of these markers may enable stratification of cervical cancer patients for implementation of personalized medicine in the clinical setting.

Hedgehog inhibition enhances efficacy of radiation and cisplatin in orthotopic cervical cancer xenografts

BACKGROUND

The Hedgehog (Hh) pathway is upregulated in cervical cancer and associated with poor outcome. We explored the effects of Hh pathway inhibition in combination with RTCT in a patient derived orthotopic cervical cancer xenograft model (OCICx).

METHODS

5E1, a monoclonal antibody for SHH, or Sonidegib (LDE225), a clinical SMO inhibitor (Novartis) were added to RTCT. We investigated tumour growth delay, metastasis and GI toxicity using orthotopic cervical cancer xenografts models. The xenografts were treated with radiotherapy (15 × 2 Gy daily fractions over 3 weeks) and weekly cisplatin 4 mg kg^-1 concurrently, with or without 5E1 or Sonidegib (LDE225). The Hh inhibitors were administered by subcutaneous injection (5E1; 20 mg kg^-1 weekly for 3 weeks), or by oral gavage (Sonidegib; 60 mg kg^-1 daily for 3 weeks).

RESULTS

We observed that both Hh inhibitors administered with RTCT were well tolerated and showed increased tumour growth delay, and reduced metastasis, with no increase in acute GI-toxicity relative to RTCT alone.

CONCLUSIONS

Our data suggest Hh can be a valid therapeutic target in cervical cancer and supports data suggesting a potential therapeutic role for targeting Hh in patients undergoing RTCT. This warrants further investigation in clinical trials.

Plerixafor Improves Primary Tumor Response and Reduces Metastases in Cervical Cancer Treated with Radio-Chemotherapy

Purpose: There is an important need to improve the effectiveness of radio-chemotherapy (RTCT) for cervical cancer. The CXCL12/CXCR4 pathway can influence RT response by recruiting normal myeloid cells to the tumor microenvironment that in turn can exert radioprotective effects, and may promote metastases. The objective of this study was to explore the efficacy and toxicity of combining RTCT with CXCL12/CXCR4 inhibition in cervical cancer.Experimental Design: CXCR4 expression was measured in 115 patients with cervical cancer. Two primary orthotopic cervical cancer xenografts (OCICx) with different levels of CXCR4 expression were treated with RT (30 Gy: 15 daily fractions) and weekly cisplatin (4 mg/kg), with or without the CXCR4 inhibitor Plerixafor (5 mg/kg/day). The endpoints were tumor growth delay and lymph node metastases. Acute intestinal toxicity was assessed using a crypt cell assay.Results: There was a fivefold variation in CXCR4 mRNA expression in the patient samples, and good correlation between the expression in patients and in the xenografts. The combination of RTCT and Plerixafor produced substantial tumor growth delay and reduced lymph node metastases compared with RTCT alone in both of the xenograft models. There was a trend toward reduced acute intestinal toxicity with the addition of Plerixafor to RTCT. There were no changes in normal organ morphology to suggest increased late toxicity.Conclusions: This study demonstrates that the addition of Plerixafor to standard RTCT improves primary tumor response and reduces metastases in cervical cancer with no increase in toxicity. This combination warrants further investigation in phase I/II clinical trials. Clin Cancer Res; 23(5); 1242-9. ©2016 AACR.

Characterization of Breast Cancer Preclinical Models Reveals a Specific Pattern of Macrophage Polarization

Drug discovery efforts have focused on the tumor microenvironment in recent years. However, few studies have characterized the stroma component in patient-derived xenografts (PDXs) and genetically engineered mouse models (GEMs). In this study, we characterized the stroma in various models of breast cancer tumors in mice. We performed transcriptomic and flow cytometry analyses on murine populations for a series of 25 PDXs and the two most commonly used GEMs (MMTV-PyMT and MMTV-erBb2). We sorted macrophages from five models. We then profiled gene expression in these cells, which were also subjected to flow cytometry for phenotypic characterization. Hematopoietic cell composition, mostly macrophages and granulocytes, differed between tumors. Macrophages had a specific polarization phenotype related to their M1/M2 classification and associated with the expression of genes involved in the recruitment, invasion and metastasis processes. The heterogeneity of the stroma component of the models studied suggests that tumor cells modify their microenvironment to satisfy their needs. Our observations suggest that such models are of relevance for preclinical studies.

Patient-derived xenograft models of squamous cell carcinoma of the uterine cervix

Patient-derived xenograft (PDX) models of cancer are considered to reflect the biology and treatment response of human tumors to a larger extent than xenograft models initiated from established cell lines. The characterization of a panel of four novel PDX models of cervical carcinoma of the uterine cervix is described in this communication. The outcome of treatment differed substantially among the donor patients, and the PDX models were found to mirror the histology, aggressiveness, and metastatic propensity of the donor patients' tumors. Two of the models (BK-12 and LA-19) were highly metastatic, one model (ED-15) was poorly metastatic, and one model (HL-16) was non-metastatic. The primary tumors of the two highly metastatic models showed high density of intratumoral lymphatics, whereas the other two models did not develop intratumoral lymphatics. The potential of the models to metastasize to lymph nodes was associated with high expression of both angiogenesis-related genes and cancer stem cell-related genes. The models may be highly valuable for studying mechanisms linking lymph node metastasis to lymphangiogenesis, hemangiogenesis, and the presence of cancer stem cells.

Patient-derived xenograft models in gynecologic malignancies

In the era of targeted therapies, patients with gynecologic malignancies have not yet been major beneficiaries of this new class of agents. This may reflect the fact that the main tumor types-ovarian, uterine, and cervical--are a highly heterogeneous group of cancers with variable response to standard chemotherapies and the lack of models in which to study the diversity of these cancers. Cancer-derived cell lines fail to adequately recapitulate molecular hallmarks of specific cancer subsets and complex microenvironments, which may be critical for sensitivity to targeted therapies. Patient-derived xenografts (PDX) generated from fresh human tumor without prior in vitro culture, combined with whole genome expression, gene copy number, and sequencing analyses, could dramatically aid the development of novel therapies for gynecologic malignancies. Gynecologic tumors can be engrafted in immunodeficient mice with a high rate of success and within a reasonable time frame. The resulting PDX accurately recapitulates the patient's tumor with respect to histologic, molecular, and in vivo treatment response characteristics. Orthotopic PDX develop complications relevant to the clinic, such as ascites and bowel obstruction, providing opportunities to understand the biology of these clinical problems. Thus, PDX have great promise for improved understanding of gynecologic malignancies, serve as better models for designing novel therapies and clinical trials, and could underpin individualized, directed therapy for patients from whom such models have been established.

Establishment of orthotopic primary cervix cancer xenografts

Standard treatment for women who are diagnosed with stage IIB through IVA cervical cancer consists of cisplatin-based chemotherapy and radiation. Current options for patients with recurrent and metastatic disease are limited, and their median overall survival is <12 months. To date, biologic therapy has had little impact on survival, so identification of potential new targets is urgently required to develop novel therapeutic strategies. Developing relevant animal models for human cervix cancer is important to further enhance our understanding of the characteristics of these tumors and for identification and assessment of novel therapies. We have established a panel of orthotopically passaged xenografts (OCICx) by implanting cervix tumor pieces from patient biopsies directly into the cervix of mice. The tumors have been passaged up to five generations, were characterized histologically for tumor and stromal content and, where possible, related to similar measurements in the original patient biopsy. The tumors were found to metastasize to the para-aortic lymphnodes allowing assessment of their metastatic potential. Preliminary studies demonstrate aberrant expression of genes in the Hedgehog (Hh) pathway in the xenografts similar to findings in primary cervix cancers. The OCICx xenografts represent unique models to test strategies for targeting essential pathways in cervix cancer and metastasis.

Development and characterization of a colon PDX model that reproduces drug responsiveness and the mutation profiles of its original tumor

Cultures of primary tumors are very useful as a personalized screening system for effective therapeutic options. We here describe an effective method of reproducing human primary colon tumors through primary culture and a mouse xenograft model. A total of 199 primary colon tumor cultures were successfully established under optimized conditions to enrich for tumor cells and to expand it for long-term storage in liquid nitrogen. To examine whether these stored cultures retained original tumor properties, fifty primary cultures were xenografted into NOD-SCID mouse. Histological and tumor marker analysis of four representative tumor xenografts revealed that all of the xenograft retained its primary tumor characteristics. Oncomap analysis further showed no change in the major mutations in the xenografts, confirming that our method faithfully reproduced human colon tumors. A drug sensitivity assay revealed that two of the primary cultures were hypersensitive to oxaliplatin rather than 5-FU, which was used in the patients, suggesting it as an effective therapeutic option. We thus present an effective, reproducible preclinical model for testing various personalized therapeutic options in colon cancer patients.

One mouse, one patient paradigm: New avatars of personalized cancer therapy

Over the last few decades, study of cancer in mouse models has gained popularity. Sophisticated genetic manipulation technologies and commercialization of these murine systems have made it possible to generate mice to study human disease. Given the large socio-economic burden of cancer, both on academic research and the health care industry, there is a need for in vivo animal cancer models that can provide a rationale that is translatable to the clinic. Such a bench-to-bedside transition will facilitate a long term robust strategy that is economically feasible and clinically effective to manage cancer. The major hurdles in considering mouse models as a translational platform are the lack of tumor heterogeneity and genetic diversity, which are a hallmark of human cancers. The present review, while critical of these pitfalls, discusses two newly emerging concepts of personalized mouse models called "Mouse Avatars" and Co-clinical Trials. Development of "Mouse Avatars" entails implantation of patient tumor samples in mice for subsequent use in drug efficacy studies. These avatars allow for each patient to have their own tumor growing in an in vivo system, thereby allowing the identification of a personalized therapeutic regimen, eliminating the cost and toxicity associated with non-targeted chemotherapeutic measures. In Co-clinical Trials, genetically engineered mouse models (GEMMs) are used to guide therapy in an ongoing human patient trial. Murine and patient trials are conducted concurrently, and information obtained from the murine system is applied towards future clinical management of the patient's tumor. The concurrent trials allow for a real-time integration of the murine and human tumor data. In combination with several molecular profiling techniques, the "Mouse Avatar" and Co-clinical Trial concepts have the potential to revolutionize the drug development and health care process. The present review outlines the current status, challenges and the future potential of these two new in vivo approaches in the field of personalized oncology.

Hypoxia and metastasis in an orthotopic cervix cancer xenograft model

BACKGROUND

Hypoxia can promote tumor metastasis by mechanisms that are believed to result from changes in gene expression. The current study examined the role of putative metastatic genes regulated by cyclic hypoxia in relation to metastasis formation in orthotopic models of cervix cancer.

METHODS

Orthotopic tumors derived from ME180 human cervix cancer cells or from early generation human cervix cancer xenografts were exposed to cyclic hypoxic conditions during growth in vivo and tumor growth and lymphnode metastases were monitored. Expression of the chemokine receptor CXCR4 and various genes in the Hedgehog (Hh) pathway were inhibited using genetic (inducible shRNA vs CXCR4) small molecule (AMD3100) or antibody (5E1) treatment (CXCR4 and Hh genes, respectively) during tumor growth.

RESULTS

As reported previously, exposure of tumor bearing mice to cyclic hypoxia caused a reduction of tumor growth but a large increase in metastasis. Inhibition of CXCR4 or Hh gene activity during tumor growth further reduced primary tumor size and reduced lymphatic metastasis to levels below those seen in control mice exposed to normoxic conditions.

CONCLUSION

Blocking CXCR4 or Hh gene expression are potential therapeutic pathways for improving cervix cancer treatment.

Establishment of patient-derived non-small cell lung cancer xenograft models with genetic aberrations within EGFR, KRAS and FGFR1: useful tools for preclinical studies of targeted therapies

BACKGROUND

Patient-derived tumor xenograft models have been established and increasingly used for preclinical studies of targeted therapies in recent years. However, patient-derived non-small cell lung cancer (NSCLC) xenograft mouse models are relatively few in number and are limited in their degree of genetic characterization and validation. In this study, we aimed to establish a variety of patient-derived NSCLC models and characterize these for common genetic aberrations to provide more informative models for preclinical drug efficacy testing.

METHODS

NSCLC tissues from thirty-one patients were collected and implanted into immunodeficient mice. Established xenograft models were characterized for common genetic aberrations, including detection of gene mutations within EGFR and KRAS, and genetic amplification of FGFR1 and cMET. Finally, gefitinib anti-tumor efficacy was tested in these patient-derived NSCLC xenograft models.

RESULTS

Ten passable patient-derived NSCLC xenograft models were established by implantation of NSCLC specimens of thirty-one patients into immunodeficient mice. Genetic aberrations were detected in six of the models, including one model with an EGFR activating mutation (Exon19 Del), one model with KRAS mutation, one model with both KRAS mutation and cMET gene amplification, and three models with FGFR1 amplification. Anti-tumor efficacy studies using gefitinib demonstrated that the EGFR activating mutation model had superior sensitivity and that the KRAS mutation models were resistant to gefitinib. The range of gefitinib responses in the patient-derived NSCLC xenograft models were consistent with the results reported from clinical trials. Furthermore, we observed that patient-derived NSCLC models with FGFR1 gene amplification were insensitive to gefitinib treatment.

CONCLUSIONS

Ten patient-derived NSCLC xenograft models were established containing a variety of genetic aberrations including EGFR activating mutation, KRAS mutation, and FGFR1 and cMET amplification. Gefitinib anti-tumor efficacy in these patient-derived NSCLC xenografts containing EGFR and KRAS mutation was consistent with the reported results from previous clinical trials. Thus, data from our panel of patient-derived NSCLC xenograft models confirms the utility of these models in furthering our understanding of this disease and aiding the development of personalized therapies for NSCLC patients.