Genome-scale CRISPR screening identifies cell cycle and protein ubiquitination processes as druggable targets for erlotinib-resistant lung cancer.

Erlotinib is highly effective in lung cancer patients with epidermal growth factor receptor (EGFR) mutations. However, despite initial favorable responses, most patients rapidly develop resistance to erlotinib soon after the initial treatment. This study aims to identify new genes and pathways associated with erlotinib resistance mechanisms in order to develop novel therapeutic strategies. Here, we induced knockout (KO) mutations in erlotinib-resistant human lung cancer cells (NCI-H820) using a genome-scale CRISPR-Cas9 sgRNA library to screen for genes involved in erlotinib susceptibility. The spectrum of sgRNAs incorporated among erlotinib-treated cells was substantially different to that of the untreated cells. Gene set analyses showed a significant depletion of \u27cell cycle process\u27 and \u27protein ubiquitination pathway\u27 genes among erlotinib-treated cells. Chemical inhibitors targeting genes in these two pathways, such as nutlin-3 and carfilzomib, increased cancer cell death when combined with erlotinib in both in vitro cell line and in vivo patient-derived xenograft experiments. Therefore, we propose that targeting cell cycle processes or protein ubiquitination pathways are promising treatment strategies for overcoming resistance to EGFR inhibitors in lung cancer

An integrative approach for exploring the nature of fibroepithelial neoplasms.

BACKGROUND: Malignant phyllodes tumour (MPT) is a rare breast malignancy with epithelial and mesenchymal features. Currently, there are no appropriate research models or effective targeted therapeutic approaches for MPT. METHODS: We collected fresh frozen tissues from nine patients with MPT and performed whole-exome and RNA sequencing. Additionally, we established patient-derived xenograft (PDX) models from patients with MPT and tested the efficacy of targeting dysregulated pathways in MPT using the PDX model from one MPT. RESULTS: MPT has unique molecular characteristics when compared to breast cancers of epithelial origin and can be classified into two groups. The PDX model derived from one patient with MPT showed that the mouse epithelial component increased during tumour growth. Moreover, targeted inhibition of platelet-derived growth factor receptor (PDGFR) and phosphoinositide 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) by imatinib mesylate and PKI-587 showed in vivo tumour suppression effects. CONCLUSIONS: This study revealed the molecular profiles of MPT that can lead to molecular classification and potential targeted therapy, and suggested that the MPT PDX model can be a useful tool for studying the pathogenesis of fibroepithelial neoplasms and for preclinical drug screening to find new therapeutic strategies for MPT

Genomic profile of metastatic breast cancer patient-derived xenografts established using percutaneous biopsy.

BACKGROUND: Metastatic breast cancer (mBC) is a complex and life-threatening disease and although it is difficult to cure, patients can benefit from sequential anticancer treatment, including endocrine therapy, targeted therapy and cytotoxic chemotherapy. The patient-derived xenograft (PDX) model is suggested as a practical tool to predict the clinical outcome of this disease as well as to screen novel drugs. This study aimed to establish PDX models in Korean patients and analyze their genomic profiles and utility for translational research. METHODS: Percutaneous core needle biopsy or punch biopsy samples were used for xenotransplantation. Whole exome sequencing and transcriptome analysis were performed to assess the genomic and RNA expression profiles, respectively. Copy number variation and mutational burden were analyzed and compared with other metastatic breast cancer genomic results. Mutational signatures were also analyzed. The antitumor effect of an ATR inhibitor was tested in the relevant PDX model. RESULTS: Of the 151 cases studied, 40 (26%) PDX models were established. Notably, the take rate of all subtypes, including the hormone receptor-positive (HR +) subtype, exceeded 20%. The PDX model had genomic fidelity and copy number variation that represented the pattern of its donor sample. TP53, PIK3CA, ESR1, and GATA3 mutations were frequently found in our samples, with TP53 being the most frequently mutated, and the somatic mutations in these genes strengthened their frequency in the PDX model. The ESR1 mutation, CCND1 amplification, and the APOBEC signature were significant features in our HR + HER2- PDX model. Fulvestrant in combination with palbociclib showed a partial response to the relevant patient\u27s tumor harboring the ESR1 mutation, and CCND1 amplification was found in the PDX model. AZD6738, an ATR inhibitor, delayed tumor growth in a relevant PDX model. CONCLUSIONS: Our PDX model was established using core needle biopsy samples from primary and metastatic tissues. Genomic profiles of the samples reflected their original tissue characteristics and could be used for the interpretation of clinical outcomes

Predictive biomarkers for 5-fluorouracil and oxaliplatin-based chemotherapy in gastric cancers via profiling of patient-derived xenografts.

Gastric cancer (GC) is commonly treated by chemotherapy using 5-fluorouracil (5-FU) derivatives and platinum combination, but predictive biomarker remains lacking. We develop patient-derived xenografts (PDXs) from 31 GC patients and treat with a combination of 5-FU and oxaliplatin, to determine biomarkers associated with responsiveness. When the PDXs are defined as either responders or non-responders according to tumor volume change after treatment, the responsiveness of PDXs is significantly consistent with the respective clinical outcomes of the patients. An integrative genomic and transcriptomic analysis of PDXs reveals that pathways associated with cell-to-cell and cell-to-extracellular matrix interactions enriched among the non-responders in both cancer cells and the tumor microenvironment (TME). We develop a 30-gene prediction model to determine the responsiveness to 5-FU and oxaliplatin-based chemotherapy and confirm the significant poor survival outcomes among cases classified as non-responder-like in three independent GC cohorts. Our study may inform clinical decision-making when designing treatment strategies

Development of high-throughput drug screening platform that reproduces the gastric cancer-specific microenvironment using 3D Bioprinting technology

In recent years, in vitro anticancer drug toxicity evaluation and drug screening tests have been increasingly attempted for the development of new drugs under conditions that reproduce an environment similar to the human body through 3D cell culture. Also, various studies have been conducted in the development of patient-derived xenograft (PDX) for investigating the efficacy of anti-cancer drugs. However, they still have the critical limitations, we have established in vitro gastric cancer PDX culture conditions using porcine gastric tissue-derived decellularized extracellular matrix (gastric dECM) to overcome their limitation. Our system provide a microenvironment for PDX growth in vitro. This process can improve production efficiency, reduce the time and cost for sub-culturing PDX and achieve mass production for drug screening. Furthermore, we confirmed different drug resistance depending on the type of PDX. These in vitro PDX culture platform might be used for various cancer drug screening as well as evaluation method to validate rapid patient-specific drug response.2

Reproduction of Tumor Microenvironment in the Multicellular 3D Bioprinted Drug Testing Platform using Patient-derived Tumor-laden Tissue-specific Bioinks

2

Development of an Ex Vivo Drug Testing Platform for Recapitulating Gastric Cancer-specific Microenvironment

Various studies have been conducted in the development of patient-derived xenograft (PDX) for investigating the efficacy of anti-cancer drugs. However, they still have the critical limitations, such as delay with engraftment time in mice and high maintenance cost. To overcome this limitation, we have established ex vivo gastric cancer PDX culture conditions using porcine stomach tissue-derived decellularized extracellular matrix (St-dECM). We fabricated a large number of samples from one PDX tissue in a day by cutting a single PDX into small pieces and encapsulating them into St-dECM. Our system provide a microenvironment for PDX growth in ex vivo. This process can improve production efficiency, reduce the time and cost for sub-culturing PDX and achieve mass production for drug screening. Furthermore, we confirmed different drug resistance depending on the type of PDX upon 5-fluorouracil treatment. These ex vivo PDX culture platform might be used for various cancer drug screening as well as evaluation method to validate rapid patient-specific drug response.1

A Novel Combination Treatment Targeting BCL-XL and MCL1 for KRAS/BRAF-mutated and BCL2L1-amplified Colorectal Cancers.

Colorectal cancer is the third most commonly diagnosed cancer in the world, and exhibits heterogeneous characteristics in terms of genomic alterations, expression signature, and drug responsiveness. Although there have been considerable efforts to classify this disease based on high-throughput sequencing techniques, targeted treatments for specific subgroups have been limited. KRAS and BRAF mutations are prevalent genetic alterations in colorectal cancers, and patients with mutations in either of these genes have a worse prognosis and are resistant to anti-EGFR treatments. In this study, we have found that a subgroup of colorectal cancers, defined by having either KRAS or BRAF (KRAS/BRAF) mutations and BCL2L1 (encoding BCL-XL) amplification, can be effectively targeted by simultaneous inhibition of BCL-XL (with ABT-263) and MCL1 (with YM-155). This combination treatment of ABT-263 and YM-155 was shown to have a synergistic effect in vitro as well as in in vivo patient-derived xenograft models. Our data suggest that combined inhibition of BCL-XL and MCL1 provides a promising treatment strategy for this genomically defined colorectal cancer subgroup. Mol Cancer Ther; 16(10); 2178-90. ©2017 AACR

Unstable Genome and Transcriptome Dynamics during Tumor Metastasis Contribute to Therapeutic Heterogeneity in Colorectal Cancers.

PURPOSE: Genomic and transcriptomic alterations during metastasis are considered to affect clinical outcome of colorectal cancers, but detailed clinical implications of metastatic alterations are not fully uncovered. We aimed to investigate the effect of metastatic evolution on EXPERIMENTAL DESIGN: We developed and analyzed patient-derived xenograft (PDX) models from 35 patients with colorectal cancer including 5 patients with multiple organ metastases (MOMs). We performed whole-exome, DNA methylation, and RNA sequencing for patient and PDX tumors. With samples from patients with MOMs, we conducted phylogenetic and subclonal analysis and RESULTS: Phylogenetic analysis using mutation, expression, and DNA methylation data in patients with MOMs showed that mutational alterations were closely connected with transcriptomic and epigenomic changes during the tumor evolution. Subclonal analysis revealed that initial primary tumors with larger number of subclones exhibited more dynamic changes in subclonal architecture according to metastasis, and loco-regional and distant metastases occurred in a parallel or independent fashion. The PDX models from MOMs demonstrated therapeutic heterogeneity for targeted treatment, due to subclonal acquisition of additional mutations or transcriptomic activation of bypass signaling pathway during tumor evolution. CONCLUSIONS: This study demonstrate

Genomic profile of metastatic breast cancer patient-derived xenografts established using percutaneous biopsy

Background Metastatic breast cancer (mBC) is a complex and life-threatening disease and although it is difficult to cure, patients can benefit from sequential anticancer treatment, including endocrine therapy, targeted therapy and cytotoxic chemotherapy. The patient-derived xenograft (PDX) model is suggested as a practical tool to predict the clinical outcome of this disease as well as to screen novel drugs. This study aimed to establish PDX models in Korean patients and analyze their genomic profiles and utility for translational research. Methods Percutaneous core needle biopsy or punch biopsy samples were used for xenotransplantation. Whole exome sequencing and transcriptome analysis were performed to assess the genomic and RNA expression profiles, respectively. Copy number variation and mutational burden were analyzed and compared with other metastatic breast cancer genomic results. Mutational signatures were also analyzed. The antitumor effect of an ATR inhibitor was tested in the relevant PDX model. Results Of the 151 cases studied, 40 (26%) PDX models were established. Notably, the take rate of all subtypes, including the hormone receptor-positive (HR +) subtype, exceeded 20%. The PDX model had genomic fidelity and copy number variation that represented the pattern of its donor sample. TP53, PIK3CA, ESR1, and GATA3 mutations were frequently found in our samples, with TP53 being the most frequently mutated, and the somatic mutations in these genes strengthened their frequency in the PDX model. The ESR1 mutation, CCND1 amplification, and the APOBEC signature were significant features in our HR + HER2- PDX model. Fulvestrant in combination with palbociclib showed a partial response to the relevant patients tumor harboring the ESR1 mutation, and CCND1 amplification was found in the PDX model. AZD6738, an ATR inhibitor, delayed tumor growth in a relevant PDX model. Conclusions Our PDX model was established using core needle biopsy samples from primary and metastatic tissues. Genomic profiles of the samples reflected their original tissue characteristics and could be used for the interpretation of clinical outcomes.This research was supported by a grant from the Korea Health Technol‑ogy R&D Project through the Korea Health Industry Development Institute (KHIDI), funded by the Ministry of Health & Welfare, Republic of Korea (800–20200226). This work was also supported by a grant from the National Research Foundation of Korea (NRF), funded by the Ministry of Science and ICT (MSIT), the Republic of Korea (0411–20200059), and partially supported by a Seoul National University Hospital research Grant (04-2016-0630). C. Lee was a distinguished Ewha Womans University Professor supported in part by the Ewha Womans University Research grant of 2017-2018. Also, this study is supported in part by the operational funds from The First Afliated Hospital of Xian Jiaotong Universit