Anti-tissue factor antibody conjugated with monomethyl auristatin E or deruxtecan in pancreatic cancer models.

Antibody-drug conjugates (ADCs) have been recognized as a promising class of cancer therapeutics. Tissue factor (TF), an initiator of the blood coagulation pathway, has been investigated regarding its relationship with cancer, and several preclinical and clinical studies have presented data on anti-TF ADCs, including tisotumab vedotin, which was approved in 2021. However, the feasibility of other payloads in the design of anti-TF ADCs is still unclear because no reports have compared payloads with different cytotoxic mechanisms. For ADCs targeting other antigens, such as Her2, optimizing the payload is also an important issue in order to improve in vivo efficacy. In this study, we prepared humanized anti-TF Ab (clone.1084) conjugated with monomethyl auristatin E (MMAE) or deruxtecan (DXd), and evaluated the efficacy in several cell line- and patient-derived xenograft models of pancreatic cancer. As a result, optimizing the drug / Ab ratio was necessary for each payload in order to prevent pharmacokinetic deterioration and maximize delivery efficiency. In addition, MMAE-conjugated anti-TF ADC showed higher antitumor effects in tumors with strong and homogeneous TF expression, while DXd-conjugated anti-TF ADC was more effective in tumors with weak and heterogeneous TF expression. Analysis of a pancreatic cancer tissue array showed weak and heterogeneous TF expression in most TF-positive specimens, indicating that the response rate to pancreatic cancer might be higher for DXd- than MMAE-conjugated anti-TF ADC. Nevertheless, our findings indicated that optimizing the ADC payloads individually in each patient could maximize the potential of ADC therapeutics.

Spheroid culture to select theoretical therapeutic drugs in intravascular large B-cell lymphoma.

Intravascular large B-cell lymphoma (IVLBCL) is a rare type of extranodal large B-cell lymphoma that is characterized by the proliferation of lymphoma cells in the lumina of small vessels. Recent progress uncovering the genetic characteristics associated with MYD88/CD79B mutations has stimulated interest in the use of drugs targeting B-cell receptor signaling, including Bruton's tyrosine kinase. However, difficulties in culturing ex vivo IVLBCL cells has hampered research on the development of novel therapies. In the present study, we demonstrated the establishment of an ex vivo culture system of IVLBCL cells obtained from patient-derived xenograft (PDX) models. The spheroid culture enabled us to culture IVLBCL PDX cells for more than 10 days and to explore the efficacy of drug treatments acting on these cells. We found that carfilzomib and ibrutinib were effective for treating IVLBCL in ex vivo experiments and conducted in vivo analyses to assess the efficacy of these drugs. Although the efficacy of carfilzomib was difficult to confirm due to its toxicity in our models, ibrutinib showed comparable efficacy to a standard combination of chemotherapy drugs. Together, our data provide a new culture method for IVLBCL PDX cells and a rationale for translating ibrutinib to clinical use in IVLBCL patients.

A Structure-Guided Genetic Modification Strategy: Developing Seneca Valley Virus Therapy against Nonsensitive Nonsmall Cell Lung Carcinoma.

Numerous studies have illustrated that the Seneca Valley virus (SVV) shows sufficient oncolytic efficacy targeting small cell lung cancer (SCLC). However, the therapeutics of nonsmall cell lung carcinoma (NSCLC, accounts for 85% of lung cancer cases) using oncolytic virus have been resisting due to the filtration of neutralizing antibody and limited reproduction capacity. Here, we employed structural biology and reverse genetics to optimize novel oncolytic SVV mutants (viral receptor-associated mutant SVV-S177A and viral antigenic peptide-related variant SVV-S177A/P60S) with increased infectivity and lower immunogenicity. The results of the NSCLC-bearing athymic mouse model demonstrated that wild-type (wt) SVV-HB extended the median overall survival (mOS) from 11 days in the PBS group to 19 days. Notably, the newly discovered mutations significantly (P < 0.001) prolonged the mOS from 11 days in the control cohort to 23 days in the SVV-S177A cohort and the SVV-S177A/P60S cohort. Taken together, we present a structure-guided genetic modification strategy for oncolytic SVV optimization and provide a candidate for developing oncolytic viral therapy against nonsensitive NSCLC. IMPORTANCE Nonsmall cell lung cancer (NSCLC) accounts for approximately 85% of lung cancer cases (more than 1.85 million cases with 1.48 million deaths in 2020). In the present study, two novel oncolytic SVV mutants modified based on structural biology and reverse genetics (viral receptor-associated mutant SVV-S177A and viral antigenic peptide-related mutant SVV-S177A/P60S) with increased infectivity or lower immunogenicity significantly (P < 0.001) prolonged the mOS from 11 days in the control cohort to 23 days in the SVV-S177A cohort and the SVV-S177A/P60S cohort in the NSCLC-bearing athymic mouse model, which may provide the direction for modifying SVV to improve the effect of oncolysis.

Establishment and characterization of a non-gestational choriocarcinoma patient-derived xenograft model.

BACKGROUND: Non-gestational choriocarcinoma (NGC) is a rare subtype of malignant germ cell tumour and there is no consensus on its treatment. The lack of suitable preclinical models for NGC is a challenge in drug discovery research. Patient-derived xenograft (PDX) models recapitulate the tumour microenvironment of the original cancer tissue. Therefore, they have received considerable attention for studies on rare cancer. Here, we aimed to establish a PDX model from a patient with recurrent NGC. METHODS: Fresh NGC tumour tissue was immediately transplanted into a severely immune-deficient mouse (NOD.Cg-Prkdcscid1l2rgtm1Wjl/SzJ) and maintained for more than three in vivo passages. Subsequently, we evaluated the molecular characteristics of the PDX model using immunohistochemistry, polymerase chain reaction, and RNA sequencing. Moreover, the PDX tumours were transplanted into BALB/c nude mice, and we evaluated their sensitivity for cisplatin and methotrexate. RESULTS: The PDX tumour maintained the morphological features of NGC. Moreover, Immunohistochemistry revealed that the human chorionic gonadotropin, cytokeratin 7, and EpCAM expression levels were similar to those in the primary tumour. Furthermore, serum human chorionic gonadotropin levels were elevated in both the primary tumour and the PDX models. Additionally, using PCR analysis with species-specific primers, we confirmed that the PDX tumour contained human genes and was derived from human tissue. Moreover, the gene expression profile of the NGC was compared with that of epithelial ovarian cancer samples and cell lines, and 568 dysregulated genes in the NGC were extracted. The expression of the dysregulated genes in PDX was significantly correlated with that in the primary tumour (R2 = 0.873, P < 0.001). Finally, we demonstrated that the PDX tumour was sensitive to cisplatin and methotrexate; therefore, its clinical response to the agents was similar to that of the primary tumour. CONCLUSIONS: We successfully established a PDX model of NGC, to the best of our knowledge, for the first time. The established PDX retained the molecular and transcriptome characteristics of the primary tumour and can be used to predict drug effects. It may facilitate further research and the development of novel therapeutic agents for NGC.

Biological evaluation of novel gemcitabine analog in patient-derived xenograft models of pancreatic cancer.

Gemcitabine (Gem) has been a standard first-line drug for pancreatic cancer (PCa) treatment; however, Gem's rapid metabolism and systemic instability (short half-life) limit its clinical outcome. The objective of this study was to modify Gem into a more stable form called 4-(N)-stearoyl-gemcitabine (4NSG) and evaluate its therapeutic efficacy in patient-derived xenograft (PDX) models from PCa of Black and White patients.Methods 4NSG was synthesized and characterized using nuclear magnetic resonance (NMR), elemental analysis, and high-performance liquid chromatography (HPLC). 4NSG-loaded solid lipid nanoparticles (4NSG-SLN) were developed using the cold homogenization technique and characterized. Patient-derived pancreatic cancer cell lines labeled Black (PPCL-192, PPCL-135) and White (PPCL-46, PPCL-68) were used to assess the in vitro anticancer activity of 4NSG-SLN. Pharmacokinetics (PK) and tumor efficacy studies were conducted using PDX mouse models bearing tumors from Black and White PCa patients.Results 4NSG was significantly stable in liver microsomal solution. The effective mean particle size (hydrodynamic diameter) of 4NSG-SLN was 82 ± 6.7 nm, and the half maximal inhibitory concentration (IC50) values of 4NSG-SLN treated PPCL-192 cells (9 ± 1.1 µM); PPCL-135 (11 ± 1.3 µM); PPCL-46 (12 ± 2.1) and PPCL-68 equaled to 22 ± 2.6 were found to be significantly lower compared to Gem treated PPCL-192 (57 ± 1.5 µM); PPCL-135 (56 ± 1.5 µM); PPCL-46 (56 ± 1.8 µM) and PPCL-68 (57 ± 2.4 µM) cells. The area under the curve (AUC), half-life, and pharmacokinetic clearance parameters for 4NSG-SLN were 3-fourfold higher than that of GemHCl. For in-vivo studies, 4NSG-SLN exhibited a two-fold decrease in tumor growth compared with GemHCl in PDX mice bearing Black and White PCa tumors.Conclusion 4NSG-SLN significantly improved the Gem's pharmacokinetic profile, enhanced Gem's systemic stability increased its antitumor efficacy in PCa PDX mice bearing Black and White patient tumors.

Adoptive NK-cell transfer as a potential treatment paradigm for Wilms tumor: A preclinical study.

BACKGROUND: Natural killer (NK) cell therapy has been shown to be effective in the treatment of some cancers. However, the effects of this adoptive immunotherapy have not been investigated for Wilms tumor (WT). In this study, the effects of adoptive NK-cell transfer on a patient-derived xenograft (PDX) model of anaplastic WT were evaluated, and the impacts of cell source and ex vivo activation strategy on the therapeutic efficacy of NK-cell product were appraised. METHODS: NK cells were isolated from human peripheral blood mononuclear cells (NKPB ) and human cord blood (NKCB ), and were expanded and activated using a cytokine cocktail. Another group of NK cells (NKET ) was produced through activation with the exosomes extracted from previously challenged NKPB cells with WT. PDX-bearing mice were treated with clinically relevant doses of NKPB , NKCB , NKET , standard chemotherapy, and placebo (phosphate-buffered saline). RESULTS: PDX models treated with NKCB showed a better survival rate, though the difference among the study groups was not significant. Compared with the placebo control group, NKCB significantly improved the histopathologic response, NKPB significantly inhibited the proliferation of neoplastic cells, and NKET led to a significant decrease in the metastasis score (all p-values <.05). Standard chemotherapy provided the greatest tumor growth inhibition and the lowest mitotic count, though it did not show any significant advantage over NK-cell therapies in any of the outcome parameters in two-by-two comparisons. CONCLUSIONS: This study spotlights the efficacy of adoptive NK-cell transfer as a potential treatment candidate for high-risk WT.

The novel indomethacin derivative CZ-212-3 exerts antitumor effects on castration-resistant prostate cancer by degrading androgen receptor and its variants.

Androgen receptor (AR) serves as a main therapeutic target for prostate cancer (PCa). However, resistance to anti-androgen therapy (SAT) inevitably occurs. Indomethacin is a nonsteroidal anti-inflammatory drug that exhibits activity against prostate cancer. Recently, we designed and synthesized a series of new indomethacin derivatives (CZ compounds) via Pd (II)-catalyzed synthesis of substituted N-benzoylindole. In this study, we evaluated the antitumor effect of these novel indomethacin derivatives in castration-resistant prostate cancer (CRPC). Upon employing CCK-8 cell viability assays and colony formation assays, we found that these derivatives had high efficacy against CRPC tumor growth in vitro. Among these derivatives, CZ-212-3 exhibited the most potent efficacy against CRPC cell survival and on apoptosis induction. Mechanistically, CZ-212-3 significantly suppressed the expression of AR target gene networks by degrading AR and its variants. Consistently, CZ-212-3 significantly inhibited tumor growth in CRPC cell line-based xenograft and PDX models in vivo. Taken together, the data show that the indomethacin derivative CZ-212-3 significantly inhibited CRPC tumor growth by degrading AR and its variants and could be a promising agent for CRPC therapy.

Enhancing the Therapeutic Efficacy of Gefitinib in Human Non-Small-Cell Lung Cancer through Drug Combination.

The interaction between tumor cells and the tumor microenvironment (TME) significantly influences tumorigenesis, so TME-targeted therapy has attracted widespread attention. We have previously demonstrated that the combination of dipyridamole, bestatin, and dexamethasone (DBD mix, DBDx) is effective against heterogeneous human pancreatic cancer and hepatocellular carcinoma in mouse xenograft models. To further expand the therapeutic potential of this drug combination, herein, we investigated the antitumor efficacy and the underlying mechanism of DBDx and the combination of DBDx and gefitinib in different mouse xenograft models of human non-small-cell lung cancer (NSCLC). Three human cancer cell lines H460, PG, and A431 were used to determine the apoptosis and growth inhibition induced by DBDx, gefitinib, and their combinations. Changes in epidermal growth factor receptor (EGFR) signaling pathway-related proteins were analyzed following treatment using western blotting. In vitro, DBDx strongly inhibited the proliferation of tumor cells, whereas the combined treatment exhibited a significant synergistic effect. Compared with DBDx, the combination treatment further induced apoptosis and downregulated the expression of molecules associated with EGFR signaling pathway. In vivo, compared with DBDx alone, the combination treatment distinctly inhibited tumor growth in mouse xenograft models of human NSCLC. Overall, our results indicate that the combination of DBDx and gefitinib in the treatment of human NSCLC is very promising, which warrants further translational studies.

CD70 antibody-drug conjugate as a potential therapeutic agent for uterine leiomyosarcoma.

BACKGROUND: Uterine leiomyosarcoma is a rare and aggressive gynecologic malignancy originating in the myometrium of the uterine corpus that tends to recur even after complete surgical excision. Current therapeutic agents have only modest effects on uterine leiomyosarcoma. Although antibodies and antibody-drug conjugates have been recognized as useful targeted therapies for other cancers, no study has yet evaluated the effects of this approach on uterine leiomyosarcoma. OBJECTIVE: This study aimed to examine the activity of tumoral CD70 in uterine leiomyosarcoma and assess the antitumor activity of CD70-antibody-drug conjugate treatment in uterine leiomyosarcoma. STUDY DESIGN: Target membrane proteins were screened by profiling and comparing membrane protein expression in 3 uterine leiomyosarcoma cell lines (SK-UT-1, SK-LMS-1, and SKN) and normal uterine myometrium cells using the isobaric tags for relative and absolute quantitation labeling method. Western blotting, fluorescence-activated cell sorting analyses, and immunohistochemistry were used to examine CD70 expression in the membrane proteins in uterine leiomyosarcoma cell lines and clinical samples. We developed an antibody-drug conjugate with a monoclonal antibody of the target membrane protein linked to monomethyl auristatin F and investigated its antitumor effects against uterine leiomyosarcoma (in vitro, in vivo, and in patient-derived xenograft models). RESULTS: CD70 was identified as a specific antigen highly expressed in uterine leiomyosarcoma cell lines. Of the 3 uterine leiomyosarcoma cell lines, CD70 expression was confirmed in SK-LMS-1 cells by western blotting and fluorescence-activated cell sorting analysis. CD70 overexpression was observed in 19 of 21 (90.5%) tumor specimens from women with uterine leiomyosarcoma. To generate CD70-antibody-drug conjugate, anti-CD70 monoclonal antibody was conjugated with a novel derivative of monomethyl auristatin F. CD70-antibody-drug conjugate showed significant antitumor effects on SK-LMS-1 cells (half maximal inhibitory concentration, 0.120 nM) and no antitumor effects on CD70-negative uterine leiomyosarcoma cells. CD70-antibody-drug conjugate significantly inhibited tumor growth in the SK-LMS-1 xenograft mouse model (tumor volume, 129.8 vs 285.5 mm3; relative reduction, 54.5%; P<.001) and patient-derived xenograft mouse model (tumor volume, 128.1 vs 837.7 mm3; relative reduction, 84.7%; P<.001). CONCLUSION: Uterine leiomyosarcoma tumors highly express CD70 and targeted therapy with CD70-antibody-drug conjugate may have a potential therapeutic implication in the treatment of uterine leiomyosarcoma.

Patient-Derived Xenograft Models in Breast Cancer Research.

Patient-derived xenograft (PDX) model can be used as a platform to study the individual patient's sensitivity to targeted agents as well as its ability to guide our understanding in various aspects of tumor biology including the tumor's clonal evolution and interaction with microenvironment. In this chapter, we review the history of PDX models in various tumor types. Additionally, we highlight the key studies that suggested potential value of PDX models in cancer treatment. Specifically, we will briefly introduce several studies on the issue of PDX models for precision medicine. In latter part of this chapter, we focus on the studies that used PDX models to investigate the molecular biology of breast cancer that underlies the process of drug resistance and tumor metastasis. Also, we will address our own experience in developing PDX models using breast cancer tissues from Korean breast cancer patients.

PDXGEM: patient-derived tumor xenograft-based gene expression model for predicting clinical response to anticancer therapy in cancer patients.

BACKGROUND: Cancer is a highly heterogeneous disease with varying responses to anti-cancer drugs. Although several attempts have been made to predict the anti-cancer therapeutic responses, there remains a great need to develop highly accurate prediction models of response to the anti-cancer drugs for clinical applications toward a personalized medicine. Patient derived xenografts (PDXs) are preclinical cancer models in which the tissue or cells from a patient's tumor are implanted into an immunodeficient or humanized mouse. In the present study, we develop a bioinformatics analysis pipeline to build a predictive gene expression model (GEM) for cancer patients' drug responses based on gene expression and drug activity data from PDX models. RESULTS: Drug sensitivity biomarkers were identified by performing an association analysis between gene expression levels and post-treatment tumor volume changes in PDX models. We built a drug response prediction model (called PDXGEM) in a random-forest algorithm by using a subset of the drug sensitvity biomarkers with concordant co-expression patterns between the PDXs and pretreatment cancer patient tumors. We applied the PDXGEM to several cytotoxic chemotherapies as well as targeted therapy agents that are used to treat breast cancer, pancreatic cancer, colorectal cancer, or non-small cell lung cancer. Significantly accurate predictions of PDXGEM for pathological response or survival outcomes were observed in extensive independent validations on multiple cancer patient datasets obtained from retrospective observational studies and prospective clinical trials. CONCLUSION: Our results demonstrated the strong potential of using molecular profiles and drug activity data of PDX tumors in developing a clinically translatable predictive cancer biomarkers for cancer patients. The PDXGEM web application is publicly available at http://pdxgem.moffitt.org .

Report of the use of patient-derived xenograft models in the development of anticancer drugs in Japan.

Cell line-derived xenograft (CDX) models created by implanting cancer cell lines into immunodeficient mice have contributed largely to the development of cancer drug therapies. However, cell lines often lose their original biological characteristics through many passages and cancer tissues in CDX models have many cancer cells and few cancer stromal cells, therefore CDX models are currently considered not suitable for predicting the results of clinical studies. Conversely, patient-derived xenograft (PDX) models are gaining importance, as human cancer biological characteristics and microenvironments are recreated by implanting tumor tissue into immunodeficient mice. These highly expected, evidently beneficial PDX models have been used in some basic research and are becoming more generalized. However, quality control and quality assurance criteria have not been established for them, and challenges and problems in the utilization of valuable PDX models in drug development have yet to be clarified. In this report, we conducted a questionnaire survey among researchers in Japanese academic institutions and pharmaceutical companies to understand the current status of PDX models in Japan. Based on the questionnaire results, we summarized the situations surrounding respondent's utilization and quality control in the development of anticancer drugs and proposed several measures to facilitate the utilization of PDX models in the development of anticancer drugs.

[Research progression in neural invasion model of pancreatic cancer].

Pancreatic cancer is a malignant tumor of the digestive system with occult onset, low early diagnosis rate, rapid progression and poor prognosis. Perineural invasion (PNI) of pancreatic cancer is considered as an important factor which leads to the poor prognosis of pancreatic cancer. Neural invasion models of pancreatic cancer can simulate the occurrence and development of neural invasion of pancreatic cancer under the complex tumor microenvironment, which is an important carrier to study the molecular mechanism, early diagnosis and treatment improvement of PNI of pancreatic cancer. The current PNI model could be broadly divided into in vivo model and in vitro model, and in vivo model could further be divided into ectopic model and in situ model. Recently, based on the in vivo and in vitro models, genetically engineered mouse models and patient-derived xenograft models have been applied. Here, the preparation methods, clinical uses and limitations of the commonly used neural invasion in vitro and in vivo models of pancreatic cancer are reviewed.

[Establishment of patient derived xenograft model of high-grade mucinous carcinoma peritonei accompanied with signet ring cells and identification of biological characteristics].

Objective: To establish the patient derived xenograft (PDX) model of pseudomyxoma peritonei (PMP), and identify the key characteristics of tumor biology of this model, in order to provide a reliable model for studying the pathological mechanisms and new therapeutic strategies of PMP. Methods: PMP tumor tissue was obtained from surgery and cut into pieces after washing. Then tumor pieces were implanted subcutaneously in BAL B/c-nu mice for 6 stable passages. In the 7th passage, tumor tissue was implanted orthotopically into abdomen. Subcutaneous tumor and orthotopic tumor were then homogenized to make tumor cell suspension, implanted into abdomen of 10 BAL B/c-nu mice through midline laparotomy, 100 µl for each. The key experimental parameters including body weight changes in the observation period, experimental peritoneal cancer index (ePCI) score at the autopsy, histopathological and immunohistochemical characteristics, and gene expression profiles by high-throughput whole-genome exon sequencing were detected and recorded. Results: The successful rate of established orthotopic PDX model of human PMP was 100% (10/10). The animals showed smooth body weight increases after tumor inoculation until day 27, then the body weight began to decrease steadily. Widespread tumor dissemination of PMP tumor through the whole abdomen was found by autopsy, including the diaphragm, liver, spleen, stomach, kidney, parietal peritoneum, bowel and mesenterium. Gelatinous ascites was also observed in abdominopelvic cavity. The ePCI score ranged from 5 to 9, with a 8 of median ePCI. Histopathological studies showed peritoneal mucinous carcinomatosis accompanied with signet ring cells (PMCA-S), obvious tumor cell atypia and parenchymal invasion.Immunohistochemistry showed the expressions of MUC1, MUC2, MUC5AC, CEA, CA199, CK20, CDX-2 and Ki-67 were positive, MUC6, CK7 and p53 were negative. Whole-exome sequencing identified that the most significant genetic alteration is the exon10 missense mutation c. 1621A>C of KIT gene, the mutation abundance was 89.7%. Conclusion: PDX model of PMCA-S is successfully established, which displays the characters of high-degree malignancy, high proliferation and strong aggressiveness.

[Advances in the mouse models of myeloid leukemia].

Mouse animal models are the most commonly used experimental tools in scientific research, which have been widely favored by researchers. The animal model of mouse leukemia appeared in the 1930s. During the past 90 years, researchers have developed various types of mouse leukemia models to simulate the development and treatment of human leukemia in order to promote effectively the elucidation of the molecular mechanism of leukemia' development and progression, as well as the development of targeted drugs for the treatment of leukemia. Considering that to myeloid leukemia, especially acute myeloid leukemia, there currently is no good clinical treatment, it is urgent to clarify its new molecular mechanism and develop new therapeutic targets. This review focuses on the various types of mouse models about myeloid leukemia used commonly in recent years, including mouse strains, myeloid leukemia cell types, and modeling methods, which are expected to provide a reference for relevant researchers to select animal models during myeloid leukemia research.

Establishment and genomic characterizations of patient-derived esophageal squamous cell carcinoma xenograft models using biopsies for treatment optimization.

BACKGROUND: Squamous cell carcinoma is the dominant type of esophageal cancer in China with many patients initially diagnosed at advanced stage. Patient-derived xenografts (PDX) models have been developed to be an important platform for preclinical research. This study aims to establish and characterize PDX models using biopsy tissue from advanced esophageal cancer patients to lay the foundation of preclinical application. METHODS: Fresh endoscopic biopsy tissues were harvested from patients with advanced esophageal cancer and implanted subcutaneously into NOD/SCID mice. Then, the PDXs were serially passaged for up to four generations. Transplantation was analyzed and genomic characteristics of xenografts were profiled using next-generation sequencing. RESULTS: Twenty-five PDX models were established (13.3%, 25/188). The latency period was 75.12 ± 19.87 days (50-120 days) for the first passage and it decreased with increasing passaging. Other than tumor stages, no differences were found between transplantations of xenografts and patient characteristics, irrespective of chemotherapy. Histopathological features and chemosensitivity of PDXs were in great accordance with primary patient tumors. Each PDX was assessed for molecular characteristics including copy number variations, somatic mutations, and signaling pathway abnormalities and these were similar to patient results. CONCLUSIONS: Our PDX models were established from real time biopsies and molecularly profiled. They might be promising for drug development and individualized therapy.

Noninvasive Detection of HER2 Expression in Gastric Cancer by 64Cu-NOTA-Trastuzumab in PDX Mouse Model and in Patients.

The purpose of this study was to establish the quality control and quantify the novel 64Cu-NOTA-Trastuzumab in gastric cancer patient-derived xenografts (PDX) mice models and patients by applying the molecular imaging technique. Trastuzumab was labeled with 64Cu using NCS-Bz-NOTA as bifunctional chelator, and hIgG1 was labeled with the same procedures as a negative control agent. HER2-positive (case 176, n = 12) and HER2-negative (case 168, n = 3) PDX models were established and validated by Western blot, DNA amplification, and immunohistochemistry (IHC). Both models were conducted for micro-PET imaging by tail injection of 18.5 MBq of 64Cu-NOTA-Trastuzumab or 64Cu-NOTA-hIgG1. Radioprobe uptake in tumor and main organs was quantified by region of interested (ROI) analysis of the micro-PET images and autoradiography. Finally, gastric cancer patients were enrolled in preliminary 64Cu-NOTA-Trastuzumab PET/CT scans. NOTA-Trastuzumab was efficiently radiolabeled with 64Cu over a 99% radiochemical purity and 17.5 GBq/µmol specific activity. The immune activity was preserved as the nonmodified antibody, and the radiopharmaceutical proved to be stable for up to 5 half-decay lives of 64Cu both in vitro and in vivo. Two serials of PDX gastric cancer models were successfully established: case 176 for HER2 positive and case 168 for HER2 negative. In micro-PET imaging studies, 64Cu-NOTA-Trastuzumab exhibits a significant higher tumor uptake (11.45 ± 0.42 ID%/g) compared with 64Cu-NOTA-IgG1 (3.25 ± 0.28 ID%/g, n = 5, p = 0.0004) at 36 h after intravenous injection. Lower level uptake of 64Cu-NOTA-Trastuzumab (6.35 ± 0.48 ID%/g) in HER2-negative PDX tumor models further confirmed specific binding of the radioprobe. Interestingly, the coinjection of 2.0 mg of Trastuzumab (15.52 ± 1.97 ID%/g) or 2.0 mg of hIgG1 (15.64 ± 3.54 ID%/g) increased the 64Cu-NOTA-Trastuzumab tumor uptake in PDX tumor (HER2+) models compared with 64Cu-NOTA-Trastuzumab alone ( p < 0.05) at 36 h postinjection. There were good correlations between micro-PET images and IHC ( n = 4) and autoradiography in PDX (HER2+) tumor tissues. Therefore, 64Cu-NOTA-Trastuzumab successfully translated to clinical PET imaging, and 64Cu-NOTA-Trastuzumab PET/CT scan in gastric cancer patients showed good detection ability. In conclusion, we reported quality control and application of novel 64Cu-NOTA-Trastuzumab for HER2 expression in PDX gastric cancer mice models and gastric cancer patients. Moreover, 64Cu-NOTA-Trastuzumab holds great potential for noninvasive PET detection, staging, and follow-up of HER2 expression in gastric cancer.

Current Update of Patient-Derived Xenograft Model for Translational Breast Cancer Research.

Despite recent advances in the treatment of patients with breast cancer (BrCa), BrCa remains the third leading cause of cancer death for women in the US due to intrinsic or acquired resistance to therapy. Continued understanding of gene expression profiling and genomic sequencing has clarified underlying intratumoral molecular heterogeneity. Recently, the patient-derived xenograft (PDX) models have emerged as a novel tool to address the issues of BrCa genomics and tumor heterogeneity, and to critically transform translational BrCa research in the preclinical setting. PDX models are generated by xenografting cancer tissue fragments obtained from patients to immune deficient mice, and can be passaged into next generations of mice. Generally, in contrast to conventional xenograft using cancer cell lines, PDXs are biologically more stable and recapitulate the individual tumor morphology, gene expression, and drug susceptibility of each patient. PDX may better model the original patient's tumor by retaining tumor heterogeneity, gene expression, and similar response to treatment. PDX models are thus thought to be more translationally relevant, especially as a drug development tool, because PDXs can capture the genetic character and heterogeneity that exists within a single patient's tumor and across a population of patients' tumors. PDX models also hold enormous potential for identifying predictive markers for therapeutic response. It has been repeatedly shown that PDX models demonstrate similar levels of activity as compared to the clinical response to therapeutic interventions. Therefore, this enables identification of therapeutic interventions that can most likely benefit a patient. This allows us to address the issues of BrCa genomics and tumor heterogeneity using PDXs in "pre-clinical" trials. Herein, we reviewed recent scientific development and future perspectives using PDX models in BrCa.

Suppressor of cytokine signaling-1 gene therapy induces potent antitumor effect in patient-derived esophageal squamous cell carcinoma xenograft mice.

Chronic inflammation is involved in cancer growth in esophageal squamous cell carcinoma (ESCC), which is a highly refractory cancer with poor prognosis. This study investigated the antitumor effect and mechanisms of SOCS1 gene therapy for ESCC. Patients with ESCC showed epigenetics silencing of SOCS1 gene by methylation in the CpG islands. We infected 10 ESCC cells with an adenovirus-expressing SOCS1 (AdSOCS1) to examine the antitumor effect and mechanism of SOCS1 overexpression. SOCS1 overexpression markedly decreased the proliferation of all ESCC cell lines and induced apoptosis. Also, SOCS1 inhibited the proliferation of ESCC cells via multiple signaling pathways including Janus kinase (JAK)/signal transducer and activator of transcription (STAT) and focal adhesion kinase (FAK)/p44/42 mitogen-activated protein kinase (p44/42 MAPK). Additionally, we established two xenograft mouse models in which TE14 ESCC cells or ESCC patient-derived tissues (PDX) were subcutaneously implanted. Mice were intra-tumorally injected with AdSOCS1 or control adenovirus vector (AdLacZ). In mice, tumor volumes and tumor weights were significantly lower in mice treated with AdSOCS1 than that with AdLacZ as similar mechanism to the in vitro findings. The Ki-67 index of tumors treated with AdSOCS1 was significantly lower than that with AdLacZ, and SOCS1 gene therapy induced apoptosis. These findings demonstrated that overexpression of SOCS1 has a potent antitumor effect against ESCC both in vitro and in vivo including PDX mice. SOCS1 gene therapy may be a promising approach for the treatment of ESCC.

Characterization of ascites-derived tumor cells from an endometrial cancer patient.

Improved treatment outcomes for the endometrial cancer patient requires precision methods to investigate the biology of this disease and clinically relevant models to test treatment drugs. Hence, we applied a personalized platform to investigate whether in vitro and in vivo models could accurately predict effective treatment regimens. We successfully expanded ascites-derived tumor cells from an endometrial cancer patient with malignant ascites using ascites collected prior to chemotherapy treatment. Hematoxylin-eosin and immunohistochemistry staining of ascites-derived tumor cells confirmed the source of endometrial cancer cells. Ascites-derived tumor cells were sensitive to cisplatin and doxorubicin single-agent treatments in CCK-8 assay and 3-D culture, a condition that more closely mimics the in vivo environment. We further showed that ascites-derived tumor cells from this patient could form tumors in NOD/SCID mice with preserved morphological characteristics. A remarkable concordance between the clinical response of cisplatin and the results of in vitro and in vivo drug tests reflected the reliability of our personalized approach in this case. Together, our results indicated that an effective platform for ex vivo and in vivo culture of ascites-derived tumor cells from our endometrial cancer patient could be applied to identify treatment options, and may be commonly used in treating cancer patients with malignant ascites in the future.