Patient-Derived Xenografts for Investigation of Acquired Resistance in Oncogene-Driven Cancers: Building a Better Mousetrap

Tubulin-binding peptide RR-171 derived from human umbilical cord serum displays antitumor activity against hepatocellular carcinoma via inducing apoptosis and activating the NF-kappa B pathway

Objectives

Hepatocellular carcinoma (HCC) still presents a high incidence of malignant tumours with poor prognosis. There is an urgent need for new therapeutic agents with high specificity, low toxicity and favourable solubility for the clinical treatment of HCC.

Materials and Methods

The bioactivity of human umbilical cord serum was investigated by proteomics biotechnology and a primitive peptide with certain biological activity was identified. The antitumour effect of RR‐171 was detected by cell viability assay in vitro, and determined by subcutaneous xenograft models assay and miniPDX assay in vivo. Pull‐down experiments were conducted to identify the potential targeting proteins of RR‐171. Immunofluorescence assay and tubulin polymerization assay were conducted to explore the relationship between RR‐171 and α‐tubulin. Fluorescence imaging in xenograft models was used to explore the biodistribution of RR‐171 in vivo. A phosphospecific protein microarray was performed to uncover the underlying signalling pathway by which RR‐171 induces tumour cell death.

Results

The results indicated that RR‐171 could be effective in the treatment of HCC in vivo and in vitro. RR‐171 could aggregate significantly in solid tumours and had no obvious systemic toxicity in vivo. RR‐171 could interact with α‐tubulin and activate the NF‐Kappa B pathway in HCC cells.

Conclusions

Taken together, RR‐171 exhibited significant antitumour activity against HCC in vivo and in vitro and could potentially be used in the clinical application of HCC.

The drugs screened by OncoVeeTM-Mini-PDX have significantly benefited the patient with HER2-positive advanced gastric cancer

Introduction

At present, the prognosis of HER2-positive advanced gastric cancer is extremely poor, and some patients fail to benefit from first-line Herceptin treatment, thus facing difficulties in choosing second-line drugs.

Case Report

Here, we report a 61-year-old male patient with HER2-positive advanced gastric cancer who is primarily resistant to Herceptin and has poor therapeutic effect.

Management & Outcome

Afterwards, the OncoVeeTM-MiniPDX-guided anticancer method was used to screen drugs for second-line treatment, which resulted in liquefaction and necrosis of the patient's lesions and improved liver function indicators, as well as rapid relief of the patient's clinical symptoms.

Discussion

In the treatment of the Herceptin-resistant patient with advanced gastric cancer, OncoVeeTM-MiniPDX method screened drugs and brought clinical benefits.

Mini-patient-derived xenograft assay based on microfluidic technology promises to be an effective tool for screening individualized chemotherapy regimens for advanced non-small cell lung cancer

Patient-derived xenograft (PDX) assay has been widely used in preclinical research in patients with multidrug-resistant lung cancer. One hundred patients with non-small cell lung cancer (NSCLC) were divided into MiniPDX group and conventional group, with 50 cases in each group. The MiniPDX assay was established by enriching high-purity tumor cells using microfluidic technology to detect the drug sensitivity of NSCLC cells. All patients underwent conventional computed tomography (CT) scans of lung and mediastinum at baseline and during follow-up. Kaplan-Meier method was used to compare the overall survival and progression-free survival of two groups. The sensitivity of the same drug in different tumor xenograft varied greatly. The overall survival, progression-free survival, and clinical benefit rate of patients in the MiniPDX-guided chemotherapy group were significantly longer than those in the conventional chemotherapy group. MiniPDX assay may be an effective tool for screening chemotherapy regimens in NSCLC patients.

Challenges and Opportunities for Childhood Cancer Drug Development

Cancer in children is rare with approximately 15,700 new cases diagnosed in the United States annually. Through use of multimodality therapy (surgery, radiation therapy, and aggressive chemotherapy), 70% of patients will be "cured" of their disease, and 5-year event-free survival exceeds 80%. However, for patients surviving their malignancy, therapy-related long-term adverse effects are severe, with an estimated 50% having chronic life-threatening toxicities related to therapy in their fourth or fifth decade of life. While overall intensive therapy with cytotoxic agents continues to reduce cancer-related mortality, new understanding of the molecular etiology of many childhood cancers offers an opportunity to redirect efforts to develop effective, less genotoxic therapeutic options, including agents that target oncogenic drivers directly, and the potential for use of agents that target the tumor microenvironment and immune-directed therapies. However, for many high-risk cancers, significant challenges remain.

Patient-Derived Xenografts Can Be Reliably Generated from Patient Clinical Biopsy Specimens

BACKGROUND

Patient-derived xenografts (PDX) are clinically relevant human cancer models that can be used to guide individualized medicine. We aimed to generate PDX models from clinically obtained biopsy specimens (surgical or image-guided) hypothesizing that low volume biopsy specimens could provide sufficient viable tissue to successfully engraft PDX models from patients with unresectable or metastatic disease.

MATERIALS AND METHODS

We maintain a prospective high volume gastrointestinal malignancy PDX program. With informed consent and institutional approval, biopsy specimens (surgical or image-guided) were obtained from patients with unresectable or metastatic tumors: pancreatic adenocarcinoma (PDAC), cholangiocarcinoma, gastric and gallbladder carcinoma. Biopsies were implanted into immunodeficient mice. Tumor growth was monitored, viable tumor was passed into subsequent generations, and histopathology was confirmed.

RESULTS

In this study, biopsy specimens from 29 patients were used for PDX engraftment. Successful PDX engraftment was variable with highest engraftment rates in gastric and gallbladder carcinoma specimens (100%) compared to engraftment rates of 33% and 29% in PDAC and cholangiocarcinoma respectively. PDX models created from metastasis biopsies compared to unresectable primary tumor tissue demonstrated higher engraftment rates (69% versus 15.4%, p = 0.001). PDX models demonstrated higher engraftment rates when biopsies were obtained during surgical operations (n = 15) compared to image-guided (n = 14) (73% versus 14%, p = 0.003). Patient age, pretreatment status, or ischemic time was not different between biopsy methods.

CONCLUSIONS

PDX models can be successfully created from clinical biopsy specimens in patients with metastatic or unresectable GI cancers. The use of clinical biopsy specimens for PDX engraftment can expand the repertoire of stage-specific PDX models for downstream basic/translational research.

Establishment of a platform of non-small-cell lung cancer patient-derived xenografts with clinical and genomic annotation

BACKGROUND

Preclinical models that can better predict therapeutic activity in clinical trials are needed in this era of personalized cancer treatment. Herein, we established genomically and clinically annotated patient-derived xenografts (PDXs) from non-small-cell lung cancer (NSCLC) patients and investigated whether these PDXs would faithfully recapitulate patient responses to targeted therapy.

METHODS

Patient-derived tumors were implanted in immunodeficient mice and subsequently expanded via re-implantation. Established PDXs were examined by light microscopy, genomic profiling, and in vivo drug testing, and the successful engraft rate was analyzed with the mutation profile, histology, or acquisition method. Finally, the drug responses of PDXs were compared with the clinical responses of the respective patients.

RESULTS

Using samples from 122 patients, we established 41 NSCLC PDXs [30 adenocarcinoma (AD), 11 squamous cell carcinoma (SQ)], among which the following driver mutation were observed: 13 EGFR-mutant, 4 ALK-rearrangement, 1 ROS1-rearrangement, 1 PIK3CA-mutant, 1 FGFR1-amplification, and 2 KRAS-mutant. We rigorously characterized the relationship of clinical features to engraftment rate and latency rates. The engraft rates were comparable across histologic type. The AD engraft rate tended to be higher for surgically resected tissues relative to biopsies, whereas similar engraft rates was observed for SQ, irrespective of the acquisition method. Notably, EGFR-mutants demonstrated significantly longer latency time than EGFR-WT (86 vs. 37days, P = 0.007). The clinical responses were recapitulated by PDXs harboring driver gene alteration (EGFR, ALK, ROS1, or FGFR1) which regressed to their target inhibitors, suggesting that established PDXs comprise a clinically relevant platform.

CONCLUSION

The establishment of genetically and clinically annotated NSCLC PDXs can yield a robust preclinical tool for biomarker, therapeutic target, and drug discovery.

Guided chemotherapy based on patient-derived mini-xenograft models improves survival of gallbladder carcinoma patients

Background

Gallbladder carcinoma is highly aggressive and resistant to chemotherapy, with no consistent strategy to guide first line chemotherapy. However, patient-derived xenograft (PDX) model has been increasingly used as an effective model for in preclinical study of chemosensitivity.

Methods

Mini-PDX model was established using freshly resected primary lesions from 12 patients with gallbladder to examine the sensitivity with five of the most commonly used chemotherapeutic agents, namely gemcitabine, oxaliplatin, 5-fluorouracil, nanoparticle albumin-bound (nab)-paclitaxel, and irinotecan. The results were used to guide the selection of chemotherapeutic agents for adjunctive treatment after the surgery. Kaplan–Meier method was used to compare overall survival (OS) and disease free survival (DFS) with 45 patients who received conventional chemotherapy with gemcitabine and oxaliplatin.

Results

Cell viability assays based on mini-PDX model revealed significant heterogeneities in drug responsiveness. Kaplan–Meier analysis showed that patients in the PDX-guided chemotherapy group had significantly longer median OS (18.6 months; 95% CI 15.9–21.3 months) than patients in the conventional chemotherapy group (13.9 months; 95% CI 11.7–16.2 months) (P = 0.030; HR 3.18; 95% CI 1.47–6.91). Patients in the PDX-guided chemotherapy group also had significantly longer median DFS (17.6 months; 95% CI 14.5–20.6 months) than patients in the conventional chemotherapy group (12.0 months; 95% CI 9.7–14.4 months) (P = 0.014; HR 3.37; 95% CI 1.67–6.79).

Conclusion

The use of mini-PDX model to guide selection of chemotherapeutic regimens could improve the outcome in patients with gallbladder carcinoma.

Prognostic value of the expression of cancer stem cell-related markers CD133 and CD44 in hepatocellular carcinoma: From patients to patient-derived tumor xenograft models

High expression of cancer stem cell (CSC) markers is related to poor prognosis of patients with hepatocellular carcinoma (HCC). However, the expression of these markers in patient-derived xenograft (PDX) models and the relationship of the expression levels of these markers between HCC patients and their PDX models at subsequent low passages are unclear. To investigate the prognostic impact of putative CSC markers in patients with HCC and in related PDX models, the expression of CD133, CD90, CD44, ALDH1, CK7, CK19, OCT4, SOX2, vimentin, nestin, CD13 and EpCam were assessed by quantitative reverse transcription-PCR (qRT-PCR) and then were validated using immunohistochemistry in tumor or peritumoral tissues from patients and tumor tissues from PDX models. Cumulative survival analysis of the patients and animals was conducted using the Kaplan-Meier method and the log-rank test. Only the expression levels of CD133 and CD44 were higher in tumor tissues than in the peritumoral tissues of HCC patients by qRT-PCR. High consistency of the prognostic value of the expression of CD133/CD44 was observed in HCC patients and the PDX models. High expression levels of CD133 and CD44 were positively related to the poor prognosis of HCC patients and to that in the PDX models. PDX HCC models in the present study have been suggested to be predictive of disease outcome, which could shed light on personalized medicine and the mechanisms of CSC marker expression on prognosis.

Evaluation of CD44 and CD133 as markers of liver cancer stem cells in Egyptian patients with HCV-induced chronic liver diseases versus hepatocellular carcinoma

Background

Cancer stem cells (CSCs) play a critical role in tumor development, progression, metastasis and recurrence.

Aim

To evaluate hepatic expression of CD44 and CD133 in Egyptian patients with HCV-induced chronic liver diseases and hepatocellular carcinomas (HCCs), and to assess its correlation with inflammatory activity scores, stages of fibrosis (in chronic hepatitis with or without cirrhosis) and grades of HCC.

Methods

This prospective case-control study was conducted on eighty subjects who attended the Tropical Diseases Department, Al-Azhar University Hospital, and in collaboration with Theodor Bilharz Research Institute (2014–2016). They were divided as follows: A) Control healthy group: Ten individuals with serologically negative HCV-Ab and HBsAg, and histopathologically normal liver, B) Seventy patients subdivided into 3 groups; Twenty subjects each, as: HCV-Ab+ non-cirrhotic, HCV-Ab+ cirrhotic and HCC. Necroinflammatory activity and fibrosis in non-neoplastic liver biopsies were scored according to the METAVIR scoring system. CD44 and CD133 immunostaining was evaluated in all groups semi-quantitatively using H score. Statistical analysis was performed by SPSS version 22, using independent-samples t-test.

Results

Our study showed a significant increase of mean CD44 & CD133 expression values with disease progression among the groups (p<0.05). Their expressions increased significantly with the inflammatory activity scores and stages of fibrosis, reaching the highest values in A3F4 score compared to A1F1 (p<0.05). Moreover, there was a significant increase of their expressions across HCC grades (p<0.05), however with no significant correlation with focal lesions size.

Conclusion

CSCs clusters exhibiting CD133+ and/or CD44+ profiles were identified in chronic hepatitis, liver cirrhosis and HCC. CD133 and CD44 expressions significantly corresponded to the increased inflammatory activity, fibrosis stages and higher tumor grades. Therefore, evaluation of CD44 and CD133 expression profiles as CSCs markers in non-neoplastic liver and HCCs can help in development of novel therapeutic agents for HCC targeting and prevention.

Combine and conquer: challenges for targeted therapy combinations in early phase trials

Our increasing understanding of cancer biology has led to the development of molecularly targeted anticancer drugs. The full potential of these agents has not, however, been realised, owing to the presence of de novo (intrinsic) resistance, often resulting from compensatory signalling pathways, or the development of acquired resistance in cancer cells via clonal evolution under the selective pressures of treatment. Combinations of targeted treatments can circumvent some mechanisms of resistance to yield a clinical benefit. We explore the challenges in identifying the best drug combinations and the best combination strategies, as well as the complexities of delivering these treatments to patients. Recognizing treatment-induced toxicity and the inability to use continuous pharmacodynamically effective doses of many targeted treatments necessitates creative intermittent scheduling. Serial tumour profiling and the use of parallel co-clinical trials can contribute to understanding mechanisms of resistance, and will guide the development of adaptive clinical trial designs that can accommodate hypothesis testing, in order to realize the full potential of combination therapies.

Tryptophan PET Imaging of the Kynurenine Pathway in Patient-Derived Xenograft Models of Glioblastoma

Increasing evidence demonstrates the immunosuppressive kynurenine pathway's (KP) role in the pathophysiology of human gliomas. To study the KP in vivo, we used the noninvasive molecular imaging tracer α-[(11)C]-methyl-l-tryptophan (AMT). The AMT-positron emission tomography (PET) has shown high uptake in high-grade gliomas and predicted survival in patients with recurrent glioblastoma (GBM). We generated patient-derived xenograft (PDX) models from dissociated cells, or tumor fragments, from 5 patients with GBM. Mice bearing subcutaneous tumors were imaged with AMT-PET, and tumors were analyzed to detect the KP enzymes indoleamine 2,3-dioxygenase (IDO) 1, IDO2, tryptophan 2,3-dioxygenase, kynureninase, and kynurenine 3-monooxygenase. Overall, PET imaging showed robust tumoral AMT uptake in PDX mice with prolonged tracer accumulation over 60 minutes, consistent with AMT trapping seen in humans. Immunostained tumor tissues demonstrated positive detection of multiple KP enzymes. Furthermore, intracranial implantation of GBM cells was performed with imaging at both 9 and 14 days postimplant, with a marked increase in AMT uptake at 14 days and a corresponding high level of tissue immunostaining for KP enzymes. These results indicate that our PDX mouse models recapitulate human GBM, including aberrant tryptophan metabolism, and offer an in vivo system for development of targeted therapeutics for patients with GBM.

Comparing Patient-Derived Xenograft and Computational Response Prediction for Targeted Therapy in Patients of Early-Stage Large Cell Lung Cancer

PURPOSE

Targeted therapy (TT) provides highly effective cancer treatment for appropriately selected individuals. A major challenge of TT is to select patients who would benefit most.

EXPERIMENTAL DESIGN

The study uses cancer material from 25 patients primarily diagnosed with non-small cell lung cancer (NSCLC). Patient-derived xenografts (PDXs) are treated with cetuximab and erlotinib. Treatment response is measured by tumor shrinkage comparing tumor volume at day 25 (V25) with tumor volume at baseline (V0). Shrinkage below 40% is considered as treatment response: V25/V0 < 0.4 (<40%). Furthermore, RNA-seq data from each tumor sample are used to predict tumor response to either treatment using an in silico molecular signaling map (MSM) approach.

RESULTS

PDX response was 40% (10/25; 95% CI [21.13%, 61.34%]) under cetuximab and 20% (5/25; 95% CI [6.83%, 40.70%]) under erlotinib. MSM predicted response was 48% (12/25; 95% CI [27.8%, 68.7%]) under cetuximab and 40% (10/25; 95% CI [21.13%, 61.34%]) under erlotinib. Agreement between PDX and MSM response prediction is substantial under cetuximab and erlotinib: 84% (21/25, P = 0.001) and 80% (20/25, P = 0.003). A total of 5 from the 25 patients have been treated with cetuximab showing a clinical response identical to both predictions.

CONCLUSIONS

For NSCLC patients, this proof-of-concept study shows a considerable agreement in response prediction from MSM and PDX approaches, but MSM saves time and laboratory resources. Our result indicates the potential of MSM-based approach for clinical decision making when selecting cancer TTs. Clin Cancer Res; 22(9); 2167-76. ©2015 AACR.

From Mice to Men and Back: An Assessment of Preclinical Model Systems for the Study of Lung Cancers

INTRODUCTION

Studies of preclinical models are essential for determining the biology of lung cancers and testing new and novel therapeutic approaches. We review the commonly used preclinical models for lung cancers and evaluate their strengths and weaknesses.

METHODS

We searched the MEDLINE database via PubMed using combinations of the following medical subject headings: lung cancer; animal models, mice; cell line, tumor; cell culture, mice; transgenic, mice; SCID, transplantation; heterologous; and genetic engineering. We reviewed the relevant published articles.

RESULTS

Multiple examples of the three major preclinical models-tumor cell lines, patient-derived xenografts, and genetically engineered mouse models-exist and have been used by investigators worldwide, with more than 15,000 relevant publications. Each model has its strengths and actual or potential weaknesses. In addition, newer forms of these models have been proposed or are in use as potential improvements over the conventional models.

CONCLUSIONS

A large number and variety of models have been developed and extensively used for the study of all major types of lung cancer. While they remain the cornerstone of preclinical studies, each model has its individual strengths and weaknesses. These must be carefully evaluated and applied to the proposed studies to obtain the maximum usefulness from the models.