Patient-derived xenografts of central nervous system metastasis reveal expansion of aggressive minor clones

BACKGROUND

The dearth of relevant tumor models reflecting the heterogeneity of human central nervous system metastasis (CM) has hindered development of novel therapies.

METHODS

We established 39 CM patient-derived xenograft (PDX) models representing the histological spectrum, and performed phenotypic and multi-omic characterization of PDXs and their original patient tumors. PDX clonal evolution was also reconstructed using allele-specific copy number and somatic variants.

RESULTS

PDXs retained their metastatic potential, with flank-implanted PDXs forming spontaneous metastases in multiple organs, including brain, and CM subsequent to intracardiac injection. PDXs also retained the histological and molecular profiles of the original patient tumors, including retention of genomic aberrations and signaling pathways. Novel modes of clonal evolution involving rapid expansion by a minor clone were identified in 2 PDXs, including CM13, which was highly aggressive in vivo forming multiple spontaneous metastases, including to brain. These PDXs had little molecular resemblance to the patient donor tumor, including reversion to a copy number neutral genome, no shared nonsynonymous mutations, and no correlation by gene expression.

CONCLUSIONS

We generated a diverse and novel repertoire of PDXs that provides a new set of tools to enhance our knowledge of CM biology and improve preclinical testing. Furthermore, our study suggests that minor clone succession may confer tumor aggressiveness and potentiate brain metastasis.

The noradrenergic profile of plasma metanephrine in neuroblastoma patients is reproduced in xenograft mice models and arise from PNMT downregulation

Metanephrines (MNs; normetanephrine (NMN), metanephrine (MN) and methoxytyramine (MT)) detected in urine or plasma represent the best biomarker for neuroblastoma (NB) diagnosis, however the metabolism of both catecholamine (CAT) and MNs remains enigmatic in NB. Using patient-derived xenograft (PDX) models derived from primary NB cells, we observed that the plasma levels of MNs in NB-PDX-bearing mice were comparable as in patients. Interestingly, murine plasma displayed an elevated fraction of glucuronidated forms of MNs relative to human plasma where sulfonated forms prevail. In tumors, the concentration ranges of MNs and CAT and the expression levels of the main genes involved in catecholamine metabolism were similar between NB-PDX and human NB tissues. Likewise, plasma and intratumoral profiles of individual MNs, with increased levels of MT and NMN relative to MN, were also conserved in mouse models as in patients. We further demonstrated the downregulation of the Phenylethanolamine N-Methyltransferase gene in NB biopsies and in NB-PDX explaining this biochemical phenotype, and giving a rational to the low levels of epinephrine and MN measured in NB affected patients. Thus, our subcutaneous murine NB-PDX models not only reproduce the phenotype of primary NB tumors, but also the metabolism of catecholamine as observed in patients. This may potentially open new avenues in preclinical studies for the follow up of novel therapeutic options for NB through the quantification of plasma MNs.

The Essential Factors of Establishing Patient-derived Tumor Model

Establishing an applicable preclinical model is vital for translational cancer research. Patient-derived xenograft has been important preclinical model systems and widely used for cancer research. Patient-derived xenograft models that represent the tumors of the patients are necessary to better translate research discoveries and to test potential therapeutic approaches. However, research in this field is hampered by the limited engraftment rate. In this review, we go over a large number of researches on patient-derived xenograft transplantation and firstly systematically summarize the main factors in methodology to successfully establish models. These results will be applied to the development of patient-derived xenograft leading to better preclinical research.

Breaking the Intracellular Redox Balance with Diselenium Nanoparticles for Maximizing Chemotherapy Efficacy on Patient-Derived Xenograft Models

Excessive oxidative stress in cancer cells can induce cancer cell death. Anticancer activity and drug resistance of chemotherapy are closely related to the redox state of tumor cells. Herein, five lipophilic Pt(IV) prodrugs were synthesized on the basis of the most widely used anticancer drug cisplatin, whose anticancer efficacy and drug resistance are closely related to the intracellular redox state. Subsequently, a series of cisplatin-sensitive and drug-resistant cell lines as well as three patient-derived primary ovarian cancer cells have been selected to screen those prodrugs. To verify if the disruption of redox balance can be combined with these Pt(IV) prodrugs, we then synthesized a polymer with a diselenium bond in the main chain for encapsulating the most effective prodrug to form nanoparticles (NP(Se)s). NP(Se)s can efficiently break the redox balance via simultaneously depleting GSH and augmenting ROS, thereby achieving a synergistic effect with cisplatin. In addition, genome-wide analysis via RNA-seq was employed to provide a comprehensive understanding of the changes in transcriptome and the alterations in redox-related pathways in cells treated with NP(Se)s and cisplatin. Thereafter, patient-derived xenograft models of hepatic carcinoma (PDX^HCC) and multidrug-resistant lung cancer (PDX^MDR) were established to evaluate the therapeutic effect of NP(Se)s, and a significant antitumor effect was achieved on both models with NP(Se)s. Overall, this study provides a promising strategy to break the redox balance for maximizing the efficacy of platinum-based cancer therapy.

Proteomic Resistance Biomarkers for PI3K Inhibitor in Triple Negative Breast Cancer Patient-Derived Xenograft Models

Simple Summary

The objective of this study is to identify potential proteomic biomarkers in triple negative breast cancer (TNBC) that associate with response to PI3K inhibitors which are in clinical trials. We tested a panel of TNBC patient-derived xenograft (PDX) models for their tumor growth response to a pan-PI3K inhibitor, BKM120. Proteomic analyses by reverse phase protein array (RPPA) of 182 markers were performed on baseline and post short-term treatment PDX samples, to correlate with tumor growth response. We identified several baseline and treatment induced proteomic biomarkers in association with resistance. These results provide important insights for the development of PI3K inhibitors in TNBC.

Abstract

PI3K pathway activation is frequently observed in triple negative breast cancer (TNBC). However, single agent PI3K inhibitors have shown limited anti-tumor activity. To investigate biomarkers of response and resistance mechanisms, we tested 17 TNBC patient-derived xenograft (PDX) models representing diverse genomic backgrounds and varying degrees of PI3K pathway signaling activities for their tumor growth response to the pan-PI3K inhibitor, BKM120. Baseline and post-treatment PDX tumors were subjected to reverse phase protein array (RPPA) to identify protein markers associated with tumor growth response. While BKM120 consistently reduced PI3K pathway activity, as demonstrated by reduced levels of phosphorylated AKT, percentage tumor growth inhibition (%TGI) ranged from 35% in the least sensitive to 84% in the most sensitive model. Several biomarkers showed significant association with resistance, including elevated baseline levels of growth factor receptors (EGFR, pHER3 Y1197), PI3Kp85 regulatory subunit, anti-apoptotic protein BclXL, EMT (Vimentin, MMP9, IntegrinaV), NFKB pathway (IkappaB, RANKL), and intracellular signaling molecules including Caveolin, CBP, and KLF4, as well as treatment-induced increases in the levels of phosphorylated forms of Aurora kinases. Interestingly, increased AKT phosphorylation or PTEN loss at baseline were not significantly correlated to %TGI. These results provide important insights into biomarker development for PI3K inhibitors in TNBC.

Corrigendum: Anlotinib Combined With Chemoradiotherapy Exhibits Significant Therapeutic Efficacy in Esophageal Squamous Cell Carcinoma

[This corrects the article DOI: 10.3389/fonc.2020.00995.].

Design of 18 nm Doxorubicin-Loaded 3-Helix Micelles: Cellular Uptake and Cytotoxicity in Patient-Derived GBM6 Cells

The fate of nanocarrier materials at the cellular level constitutes a critical checkpoint in the development of effective nanomedicines, determining whether tissue level accumulation results in therapeutic benefit. The cytotoxicity and cell internalization of ∼18 nm 3-helix micelle (3HM) loaded with doxorubicin (DOX) were analyzed in patient-derived glioblastoma (GBM) cells in vitro. The half-maximal inhibitory concentration (IC₅₀) of 3HM-DOX increased to 6.2 μg/mL from <0.5 μg/mL for free DOX in patient-derived GBM6 cells, to 15.0 μg/mL from 6.5 μg/mL in U87MG cells, and to 21.5 μg/mL from ∼0.5 μg/mL in LN229 cells. Modeling analysis of previous 3HM biodistribution results predicts that these cytotoxic concentrations are achievable with intravenous injection in rodent GBM models. 3HM-DOX formulations were internalized intact and underwent intracellular trafficking distinct from free DOX. 3HM was quantified to have an internalization half-life of 12.6 h in GBM6 cells, significantly longer than that reported for some liposome and polymer systems. 3HM was found to traffic through active endocytic processes, with clathrin-mediated endocytosis being the most involved of the pathways studied. Inhibition studies suggest substantial involvement of receptor recognition in 3HM uptake. As the 3HM surface is PEG-ylated with no targeting functionalities, protein corona-cell surface interactions, such as the apolipoprotein-low-density lipoprotein receptor, are expected to initiate internalization. The present work gives insights into the cytotoxicity, pharmacodynamics, and cellular interactions of 3HM and 3HM-DOX relevant for ongoing preclinical studies. This work also contributes to efforts to develop predictive mathematical models tracking the accumulation and biodistribution kinetics at a systemic level.

A Universal Gelfoam 3-D Histoculture Method to Establish Patient-derived Cancer Cells (3D-PDCC) Without Fibroblasts from Patient-derived Xenografts

BACKGROUND/AIM

The direct placement of patient tumors in 2-D culture on plastic or glass surfaces has inhibited the establishment of patient-derived cancer cells (PDCCs). The aim of the present study was to develop universal and efficient methods to prepare PDCCs.

MATERIALS AND METHODS

Fragments of patient-derived xenograft (PDX) tumors established form colon cancer liver metastasis (1 mm³) were placed on Gelfoam and cultured in DMEM.

RESULTS

PDX tumor fragments were cultured on Gelfoam. Cancer cells migrated from the explant and formed distinct 3-D structures in the Gelfoam. Each of the three PDCCs showed a distinct morphology. The cultures were essentially all cancer cells without fibroblasts, the opposite of what usually occurs in 2-D culture on plastic or glass. Gelfoam cultures could be readily passaged from one Gelfoam cube to anothers suggesting indefinite culture potential.

CONCLUSION

A potentially universal method to establish PDCC using PDX tumors and 3-D Gelfoam histoculture was developed.

Establishment of a patient-derived xenograft model and cell line of malignant transformation of mature cystic teratoma of the ovary

AIM

Malignant transformation of mature cystic teratoma (MTMCT) of the ovary is a rare gynecological malignancy and commonly arises in women older than 50 years of age. The most common histological type of MTMCT is squamous cell carcinoma (SCC), and the prognosis is extremely poor. Patient-derived xenograft (PDX) models are promising animal models for preclinical drug screening. Here, we report the generation of a new PDX model of MTMCT, and a new cell line established from the tumors of PDX model animals.

METHODS

Tumor tissue was obtained from a 32-year-old patient with MTMCT. To generate PDX, NSG (NOD.Cg-Prkdc^scid Il2rg^tm1Wjl /SzJ) mice, a strain of super-immunodeficient mice, were used. Tumor-bearing mice were sacrificed, followed by the collection of these tumors and re-transplantation into new NSG mice (in vivo passage). Tumor samples were also cultured in vitro. Adherent cells were continuously cultured and passaged, a cell line was established.

RESULTS

In the primary PDX mouse, tumor engraftment was confirmed 30 days after tumor implantation. After three times in vivo passage, we confirmed that the cryopreserved tumors could be engrafted even when transplanted into BALB/c nude mice. Using the tumor tissue at the time of the first in vivo passage, a new cell line NOSCC1 was established. PDX tumors and cell-line derived xenograft tumors exhibited similar morphology of SCC.

CONCLUSION

We established a new PDX model of MTMCT and a new cell line of it, which may be important tools for the development of new therapies and the elucidation of the carcinogenic mechanisms of MTMCT.

Near-Infrared Light Irradiation Induced Mild Hyperthermia Enhances Glutathione Depletion and DNA Interstrand Cross-Link Formation for Efficient Chemotherapy

DNA alkylating agents generally kill tumor cells by covalently binding with DNA to form interstrand or intrastrand cross-links. However, in the case of cisplatin, only a few DNA adducts (<1%) are highly toxic irreparable interstrand cross-links. Furthermore, cisplatin is rapidly detoxified by high levels of intracellular thiols such as glutathione (GSH). Since the discovery of its mechanism of action, people have been looking for ways to directly and efficiently remove intracellular GSH and increase interstrand cross-links to improve drug efficacy and overcome resistance, but there has been little breakthrough. Herein, we hypothesized that the anticancer efficiency of cisplatin can be enhanced through iodo-thiol click chemistry mediated GSH depletion and increased formation of DNA interstrand cross-links via mild hyperthermia triggered by near-infrared (NIR) light. This was achieved by preparing an amphiphilic polymer with platinum(IV) (Pt(IV)) prodrugs and pendant iodine atoms (iodides). The polymer was further used to encapsulate IR780 and assembled into Pt-I-IR780 nanoparticles. Induction of mild hyperthermia (43 °C) at the tumor site by NIR light irradiation had three effects: (1) it accelerated the GSH-mediated reduction of Pt(IV) in the polymer main chain to platinum(II) (Pt(II)); (2) it boosted the iodo-thiol substitution click reaction between GSH and iodide, thereby attenuating the GSH-mediated detoxification of cisplatin; (3) it increased the proportion of highly toxic and irreparable Pt-DNA interstrand cross-links. Therefore, we find that mild hyperthermia induced via NIR irradiation can enhance the killing of cancer cells and reduce the tumor burden, thus delivering efficient chemotherapy.

Dihydroartemisinin Inhibits the Proliferation of Esophageal Squamous Cell Carcinoma Partially by Targeting AKT1 and p70S6K

Dihydroartemisinin (DHA), a sesquiterpene lactone with endoperoxide bridge, is one of the derivatives of artemisinin. In addition to having good antimalarial properties, DHA exhibits anticancer effects including against malignant solid tumors. However, the mechanism by which DHA inhibits the progression of esophageal cancer, especially esophageal squamous cell carcinoma (ESCC), is unclear. In this study, DHA was found to inhibit the proliferation of ESCC, and the underlying molecular mechanisms were explored. DHA inhibited ESCC cells proliferation and anchorage-independent growth. Flow cytometry analysis revealed that DHA significantly blocked cell cycle in the G1 phase. The results of human phospho-kinase array revealed that DHA downregulated the levels of p70S6K^T389 and p70S6K^T421/S424. Furthermore, the levels of mTOR^S2448, p70S6K^T389, p70S6K^T421/S424 and RPS6^S235/S236 were decreased after DHA treatment in KYSE30 and KYSE150 cells. We then explored the proteins targeted by DHA to inhibit the mTOR-p70S6K-RPS6 pathway. Results of the in vitro kinase assay revealed that DHA significantly inhibited phosphorylation of mTOR^S2448 by binding to AKT1 and p70S6K kinases. In vivo, DHA inhibited the tumor growth of ESCC patient-derived xenografts and weakened p-mTOR, p-p70S6K, and p-RPS6 expression in tumor tissues. Altogether, our results indicate that DHA has antiproliferative effects in ESCC cells and can downregulate mTOR cascade pathway partially by binding to AKT1 and p70S6K. Thus, DHA has considerable potential for the prevention or treatment of ESCC.

High levels of human epididymis protein 4 mRNA and protein expression are associated with chemoresistance and a poor prognosis in pancreatic cancer

Pancreatic cancer is associated with an exceedingly poor prognosis, warranting the development of novel therapeutic strategies and discovery of prognostic predictors. Given that chemoresistance‑related molecules are reportedly associated with the poor prognosis of pancreatic cancer, the present study aimed to identify molecules that could be efficacious therapeutic targets for pancreatic cancer. First, 10 patient‑derived xenografts (PDXs) were established from patients with pancreatic cancer. Subsequently, after treating tumor tissue generated from the PDXs with standard drugs, next‑generation sequencing (NGS) was performed using these tissues. The results of NGS analysis and immunohistochemical analysis on 80 pancreatic cancer tissues revealed that human epididymis protein 4 (HE4) expression in the anticancer drug‑treated PDX group was higher than that in the untreated PDXs. In addition, chemoresistance ability was observed in tumor cell lines overexpressing HE4. Furthermore, Kaplan‑Meier analysis of tumor tissues from 80 patients with pancreatic cancer was performed and it was found that patients with a high HE4 expression level had a poor survival rate compared with those who had a low HE4 expression level. Multivariate analysis also indicated the high expression level of HE4 was an independent poor prognostic biomarker. Thus, it was concluded that high gene and protein expression levels of HE4 mediate chemoresistance and are independent prognostic factors for pancreatic cancer.

Xenograft-based, platform-independent gene signatures to predict response to alkylating chemotherapy, radiation, and combination therapy for glioblastoma

BACKGROUND

Predictive molecular biomarkers to select optimal treatment for patients with glioblastoma and other cancers are lacking. New strategies are needed when large randomized trials with correlative molecular data are not feasible.

METHODS

Gene signatures (GS) were developed from 31 orthotopic glioblastoma patient-derived xenografts (PDXs), treated with standard therapies, to predict benefit from radiotherapy (RT-GS), temozolomide (Chemo-GS), or the combination (ChemoRT-GS). Independent validation was performed in a heterogeneously treated clinical cohort of 502 glioblastoma patients with overall survival as the primary endpoint. Multivariate Cox analysis was used to adjust for confounding variables and evaluate interactions between signatures and treatment.

RESULTS

PDX models recapitulated the clinical heterogeneity of glioblastoma patients. RT-GS, Chemo-GS, and ChemoRT-GS were correlated with benefit from treatment in the PDX models. In independent clinical validation, higher RT-GS scores were associated with increased survival only in patients receiving RT (P = 0.0031, hazard ratio [HR] = 0.78 [0.66-0.92]), higher Chemo-GS scores were associated with increased survival only in patients receiving chemotherapy (P < 0.0001, HR = 0.66 [0.55-0.8]), and higher ChemoRT-GS scores were associated with increased survival only in patients receiving ChemoRT (P = 0.0001, HR = 0.54 [0.4-0.74]). RT-GS and ChemoRT-GS had significant interactions with treatment on multivariate analysis (P = 0.0009 and 0.02, respectively), indicating that they are bona fide predictive biomarkers.

CONCLUSIONS

Using a novel PDX-driven methodology, we developed and validated 3 platform-independent molecular signatures that predict benefit from standard of care therapies for glioblastoma. These signatures may be useful to personalize glioblastoma treatment in the clinic and this approach may be a generalizable method to identify predictive biomarkers without resource-intensive randomized trials.

A cell-penetrating MARCKS mimetic selectively triggers cytolytic death in glioblastoma

Glioblastoma (GBM) is an aggressive malignancy with limited effectiveness of standard of care therapies including surgery, radiation, and temozolomide chemotherapy necessitating novel therapeutics. Unfortunately, GBMs also harbor several signaling alterations that protect them from traditional therapies that rely on apoptotic programmed cell death. Because almost all GBM tumors have dysregulated phosphoinositide signaling as part of that process, we hypothesized that peptide mimetics derived from the phospholipid binding domain of Myristoylated alanine-rich C-kinase substrate (MARCKS) could serve as a novel GBM therapeutic. Using molecularly classified patient-derived xenograft (PDX) lines, cultured in stem-cell conditions, we demonstrate that cell permeable MARCKS effector domain (ED) peptides potently target all GBM molecular classes while sparing normal human astrocytes. Cell death mechanistic testing revealed that these peptides produce rapid cytotoxicity in GBM that overcomes caspase inhibition. Moreover, we identify a GBM-selective cytolytic death mechanism involving plasma membrane targeting and intracellular calcium accumulation. Despite limited relative partitioning to the brain, tail-vein peptide injection revealed tumor targeting in intracranially implanted GBM PDX. These results indicate that MARCKS ED peptide therapeutics may overcome traditional GBM resistance mechanisms, supporting further development of similar agents.

Anti-Cancer Activity of As4O6 and its Efficacy in a Series of Patient-Derived Xenografts for Human Cervical Cancer

Purpose: To investigate the anti-cancer effects of tetraarsenic hexoxide (TAO, As₄O₆) in cervical cancer cell lines and in a series of patient-derived xenograft (PDX) mouse models. Methods: Human cervical cancer cell lines, including HeLa, SiHa and CaSki, and human umbilical vein endothelial cells (HUVECs), were used to evaluate the anti-cancer activity of TAO. Cellular proliferation, apoptosis, and enzyme-linked immunosorbent assay (ELISA) for matrix metallopeptidase 2 (MMP-2) and 9 (MMP-9) were assessed. The tumor weights of the PDXs that were given TAO were measured. The PDXs included primary squamous cell carcinoma, primary adenocarcinoma, recurrent squamous cell carcinoma, and recurrent adenocarcinoma. Results: TAO significantly decreased cellular proliferation and increased apoptosis in cervical cancer cell lines and HUVEC. The functional studies on the cytotoxicity of TAO revealed that it inhibited the activation of Akt and vascular endothelial growth factor receptor 2 (VEGFR2). It also decreased the concentrations of MMP-2 in both cervical cancer cell lines and HUVECs. Active caspase-3 and p62 were both increased by the treatment of TAO, indicating increased rates of apoptosis and decreased rates of autophagy, respectively. In vivo studies with PDXs revealed that TAO significantly decreased tumor weight for both primary squamous cell carcinoma and adenocarcinoma of the cervix. However, this anti-cancer effect was not seen in PDXs with recurrent cancers. Nevertheless, the combination of TAO with cisplatin significantly decreased tumor weight in PDX models for both primary and recurrent cancers. Conclusions: TAO exerted inhibitory effects on angiogenesis, cellular migration, and autophagy, and it showed stimulatory effects on apoptosis. Overall, it demonstrated anti-cancer effects in animal models for human cervical cancer.

A Novel Orthotopic Patient-Derived Xenograft Model of Radiation-Induced Glioma Following Medulloblastoma

Radiation-induced glioma (RIG) is a highly aggressive brain cancer arising as a consequence of radiation therapy. We report a case of RIG that arose in the brain stem following treatment for paediatric medulloblastoma, and the development and characterisation of a matched orthotopic patient-derived xenograft (PDX) model (TK-RIG915). Patient and PDX tumours were analysed using DNA methylation profiling, whole genome sequencing (WGS) and RNA sequencing. While initially thought to be a diffuse intrinsic pontine glioma (DIPG) based on disease location, results from methylation profiling and WGS were not consistent with this diagnosis. Furthermore, clustering analyses based on RNA expression suggested the tumours were distinct from primary DIPG. Additional gene expression analysis demonstrated concordance with a published RIG expression profile. Multiple genetic alterations that enhance PI3K/AKT and Ras/Raf/MEK/ERK signalling were discovered in TK-RIG915 including an activating mutation in PIK3CA, upregulation of PDGFRA and AKT2, inactivating mutations in NF1, and a gain-of-function mutation in PTPN11. Additionally, deletion of CDKN2A/B, increased IDH1 expression, and decreased ARID1A expression were observed. Detection of phosphorylated S6, 4EBP1 and ERK via immunohistochemistry confirmed PI3K pathway and ERK activation. Here, we report one of the first PDX models for RIG, which recapitulates the patient disease and is molecularly distinct from primary brain stem glioma. Genetic interrogation of this model has enabled the identification of potential therapeutic vulnerabilities in this currently incurable disease.

Patient-Derived Xenografts as an Innovative Surrogate Tumor Model for the Investigation of Health Disparities in Triple Negative Breast Cancer

Despite a decline in overall incidence rates for cancer in the past decade, due in part to impressive advancements in both diagnosis and treatment, breast cancer (BC) remains the leading cause of cancer-related deaths in women. BC alone accounts for ∼30% of all new cancer diagnoses in women worldwide. Triple-negative BC (TNBC), defined as having no expression of the estrogen or progesterone receptors and no amplification of the HER2 receptor, is a subtype of BC that does not benefit from the use of estrogen receptor-targeting or HER2-targeting therapies. Differences in socioeconomic factors and cell intrinsic and extrinsic characteristics have been demonstrated in Black and White TNBC patient tumors. The emergence of patient-derived xenograft (PDX) models as a surrogate, translational, and functional representation of the patient with TNBC has led to the advances in drug discovery and testing of novel targeted approaches and combination therapies. However, current established TNBC PDX models fail to represent the diverse patient population and, most importantly, the specific ethnic patient populations that have higher rates of incidence and mortality. The primary aim of this review is to emphasize the importance of using clinically relevant translatable tumor models that reflect TNBC human tumor biology and heterogeneity in high-risk patient populations. The focus is to highlight the complexity of BC as it specifically relates to the management of TNBC in Black women. We discuss the importance of utilizing PDX models to study the extracellular matrix (ECM), and the distinct differences in ECM composition and biophysical properties in Black and White women. Finally, we demonstrate the crucial importance of PDX models toward novel drug discovery in this patient population.

ZenoFishDb v1.1: A Database for Xenotransplantation Studies in Zebrafish

Rapidly accumulating literature has proven feasibility of the zebrafish xenograft models in cancer research. Nevertheless, online databases for searching the current zebrafish xenograft literature are in great demand. Herein, we have developed a manually curated database, called ZenoFishDb v1.1 (https://konulab.shinyapps.io/zenofishdb), based on R Shiny platform aiming to provide searchable information on ever increasing collection of zebrafish studies for cancer cell line transplantation and patient-derived xenografts (PDXs). ZenoFishDb v1.1 user interface contains four modules: DataTable, Visualization, PDX Details, and PDX Charts. The DataTable and Visualization pages represent xenograft study details, including injected cell lines, PDX injections, molecular modifications of cell lines, zebrafish strains, as well as technical aspects of the xenotransplantation procedures in table, bar, and/or pie chart formats. The PDX Details module provides comprehensive information on the patient details in table format and can be searched and visualized. Overall, ZenoFishDb v1.1 enables researchers to effectively search, list, and visualize different technical and biological attributes of zebrafish xenotransplantation studies particularly focusing on the new trends that make use of reporters, RNA interference, overexpression, or mutant gene constructs of transplanted cancer cells, stem cells, and PDXs, as well as distinguished host modifications.

PDX: Moving Beyond Drug Screening to Versatile Models for Research Discovery

Patient-derived xenografts (PDXs) are tools of the trade for many researchers from all disciplines and medical specialties. Most endocrinologists, and especially those working in oncology, commonly use PDXs for preclinical drug testing and development, and over the last decade large collections of PDXs have emerged across all tumor streams. In this review, we examine how the field has evolved to include PDXs as versatile resources for research discoveries, providing evidence for guidelines and changes in clinical practice.

Biological Characterization and Therapeutics for Subscalp Recurrent in Intracranial Glioblastoma

Purpose

Gliomas are common intracranial tumors, of which 70% are malignant gliomas. Glioblastoma multiforme (GBM) is the most aggressive tumor, and patients with GBM have a median survival time of only 9–12 months; extracranial recurrence of GBM is very rare. A therapeutic strategy for this kind of recurrent tumor is lacking.

Materials and Methods

We present a case of a patient with extracranial recurrence of subscalp GBM. The subscalp tumor was resected and xenotransplanted into BALB/C nude mice. Then, glioma cells were isolated from the xenograft models and passaged in vitro. HE staining, immunohistochemistry, CCK-8 assays, karyotypic analysis, short tandem repeat STR analysis and flow cytometry were used to analyze the biological characteristics and malignant phenotype of these established cells. The cells and xenografts were then used as preclinical models to evaluate the antitumor efficacy of oncolytic herpes simplex virus 1 (oHSV-1).

Results

The isolated cells, which were named BT-01, were positive for Nestin and GFAP. The main characteristics of BT-01 cells were that they harbored glioblastoma stem-like cells (GSCs) and that they possessed highly aggressive migration capacities compared with the existing cell lines U87-MG and U251-MG. Moreover, BT-01 cells tolerated the chemotherapeutic drug temozolomide. Our study showed that oHSV-1 could replicate in and repress the growth of BT-01 cells and significantly inhibit tumor growth in xenograft models.

Conclusion

Taken together, our results showed that a new recurrent glioblastoma cell line was established, which can be useful for research on recurrent glioblastoma. We provided a reliable preclinical model to evaluate the antitumor efficacy of oHSV-1 in vivo and a promising therapy for recurrent GBM.

Neuroblastoma patient-derived cultures are enriched for a mesenchymal gene signature and reflect individual drug response

Ex vivo evaluation of personalized models can facilitate individualized treatment selection for patients, and advance the discovery of novel therapeutic options. However, for embryonal malignancies, representative primary cultures have been difficult to establish. We developed patient‐derived cell cultures (PDCs) from chemo‐naïve and post–treatment neuroblastoma tumors in a consistent and efficient manner, and characterized their in vitro growth dynamics, histomorphology, gene expression, and functional chemo‐response. From 34 neuroblastoma tumors, 22 engrafted in vitro to generate 31 individual PDC lines, with higher engraftment seen with metastatic tumors. PDCs displayed characteristic immunohistochemical staining patterns of PHOX2B, TH, and GD2 synthase. Concordance of MYCN amplification, 1p and 11q deletion between PDCs and patient tumors was 83.3%, 72.7%, and 80.0% respectively. PDCs displayed a predominantly mesenchymal‐type gene expression signature and showed upregulation of pro‐angiogenic factors that were similarly enriched in culture medium and paired patient serum samples. When tested with standard‐of‐care cytotoxics at human C_max‐equivalent concentrations, MYCN‐amplified and non‐MYCN‐amplified PDCs showed a differential response to cyclophosphamide and topotecan, which mirrored the corresponding patients’ responses, and correlated with gene signatures of chemosensitivity. In this translational proof‐of‐concept study, early‐phase neuroblastoma PDCs enriched for the mesenchymal cell subpopulation recapitulated the individual molecular and phenotypic profile of patient tumors, and highlighted their potential as a platform for individualized ex vivo drug‐response testing.

Bitter melon juice intake with gemcitabine intervention circumvents resistance to gemcitabine in pancreatic patient-derived xenograft tumors

Chemoresistance to gemcitabine (GEM)-a frontline chemotherapeutic, resulting from its dysfunctional uptake and metabolism in cancer cells, is a major contributing factor for failed therapy in pancreatic cancer (PanC) patients. Therefore, there is an urgent need for agents that could reverse GEM resistance and allow continued chemosensitivity to the drug. We employed natural nontoxic agent (with anti-PanC potential) bitter melon juice (BMJ) and GEM to examine their combinatorial benefits against tumorigenesis of PanC patient-derived xenograft (PDX)-pancreatic ductal adenocarcinomas explants PDX272 (wild-type KRAS), PDX271 (mutant KRAS and SMAD4), and PDX266 (mutant KRAS). Anti-PanC efficacy of single agents vs combination in the three tumor explants, both at the end of active dosing regimen and following a drug-washout phase were compared. In animal studies, GEM alone treatment significantly inhibited PDX tumor growth, but effects were not sustained, as GEM-treated tumors exhibited regrowth posttreatment termination. However, combination-regimen displayed enhanced and sustained efficacy. Mechanistic assessments revealed that overcoming GEM resistance by coadministration with BMJ was possibly due to modulation of GEM transport/metabolism pathway molecules (ribonucleotide reductase regulatory subunit M1, human equilibrative nucleoside transporter 1, and deoxycytidine kinase). Study outcomes, highlighting significantly higher and sustained efficacy of GEM in combination with BMJ, make a compelling case for a clinical trial in PanC patients, wherein BMJ could be combined with GEM to target and overcome GEM resistance. In addition, given their specific effectiveness against KRAS-mutant tumors, this combination could be potentially beneficial to a broader PanC patient population.

Omeprazole Inhibits Glioblastoma Cell Invasion and Tumor Growth

Background: The aryl hydrocarbon receptor (AhR) is expressed in gliomas and the highest staining is observed in glioblastomas. A recent study showed that the AhR exhibited tumor suppressor-like activity in established and patient-derived glioblastoma cells and genomic analysis showed that this was due, in part, to suppression of CXCL12, CXCR4 and MMP9. Methods: Selective AhR modulators (SAhRMs) including AhR-active pharmaceuticals were screened for their inhibition of invasion using a spheroid invasion assay in patient-derived AhR-expressing 15-037 glioblastoma cells and in AhR-silenced 15-037 cells. Invasion, migration and cell proliferation were determined using spheroid invasion, Boyden chambers and scratch assay, and XTT metabolic assays for cell growth. Changes in gene and gene product expression were determined by real-time PCR and Western blot assays, respectively. In vivo antitumorigenic activity of omeprazole was determined in SCID mice bearing subcutaneous patient-derived 15-037 cells. Results: Results of a screening assay using patient-derived 15-037 cells (wild-type and AhR knockout) identified the AhR-active proton pump inhibitor omeprazole as an inhibitor of glioblastoma cell invasion and migration only AhR-expressing cells but not in cells where the AhR was downregulated. Omeprazole also enhanced AhR-dependent repression of the pro-invasion CXCL12, CXCR4 and MMP9 genes, and interactions and effectiveness of omeprazole plus temozolomide were response-dependent. Omeprazole (100 mg/kg/injection) inhibited and delayed tumors in SCID mice bearing patient-derived 15-037 cells injected subcutaneously. Conclusion: Our results demonstrate that omeprazole enhances AhR-dependent inhibition of glioblastoma invasion and highlights a potential new avenue for development of a novel therapeutic mechanism-based approach for treating glioblastoma.

ROS-Activatable siRNA-Engineered Polyplex for NIR-Triggered Synergistic Cancer Treatment

Small interfering RNA (siRNA) shows excellent pharmaceutical prospects in treating diverse life-threatening diseases. Photodynamic therapy (PDT) is a clinically employed noninvasive treatment method that can trigger selective damage toward targeted tissue and cells. However, insufficient delivery of siRNA and photosensitizer to cancer cells remarkably hindered the application of siRNA and PDT in the treatment of cancer. In this study, a unique reactive oxygen species (ROS)-activatable polyplex, which consists of the PEGylated cationic polymer, ROS-cleavable linker, photosensitizer Ce6, and RRM2-against siRNA, termed PPTC/siRNA, was engineered. Upon irradiation of near-infrared (NIR) light, the polyplex efficiently generated ROS, which triggered degradation of the ROS-sensitive linker, disassembling the complex, destabilization of the cell membrane, and significantly accelerated cellular entry and endosomal escape of siRNA. Besides achieving effective siRNA internalization and gene silence in cancer cells in vitro, PPTC/siRNA synergistically inhibited tumor growth in both cell line-derived xenograft and patient-derived xenograft hepatocellular carcinoma murine models by repressing the RRM2 expression (reducing cell proliferation) and triggering photodynamic killing (enhancing cell apoptosis). The proposed polyplex also showed ideal safety profiles both in cell line and in animal. It provides a novel strategy for NIR-triggered RNAi and PDT combinational cancer treatment.

Generation of Glioblastoma Patient-Derived Intracranial Xenografts for Preclinical Studies

Glioblastoma multiforme (GBM) is the most malignant primary brain cancer affecting adults. Therapeutic options for GBM have remained the same for over a decade with no significant improvement. Many therapies that are successful in culture have failed in patients, likely due to the complex microenvironment in the brain, which has yet to be reproduced in any culture model. Furthermore, the high passage number of cultured cells and clonal selection fail to recapitulate the molecular and genomic signatures of GBM. We have established orthotopic patient-derived xenografts (PDX) from 37 GBM patients with human GBM. Of the 69 patient samples analyzed, we were successful in passaging 37 lines three or more generations (53.6%). After phenotypic characterization of the xenografted tumor tissue, two different growth patterns emerged highly invasive or localized. The phenotype was dependent on malignancy and previous treatment of the patient from which the xenograft was derived. Physiologically, mice exhibited symptoms more quickly with each subsequent passage, particularly in the localized tumors. Study of these physiologically relevant human xenografts in mice will enable therapeutic screenings in a microenvironment that more closely resembles GBM and may allow development of individualized patient models which may eventually be used for simulating treatment.