STAT6-targeting antisense oligonucleotides against solitary fibrous tumor

Solitary fibrous tumor (SFT) is a rare, non-hereditary soft tissue sarcoma thought to originate from fibroblastic mesenchymal stem cells. The etiology of SFT is thought to be due to an environmental intrachromosomal gene fusion between NGFI-A-binding protein 2 (NAB2) and signal transducer and activator protein 6 (STAT6) genes on chromosome 12, wherein the activation domain of STAT6 is fused with the DNA-binding domain of NAB2 resulting in the oncogenesis of SFT. All NAB2-STAT6 fusion variations discovered in SFTs contain the C-terminal of STAT6 transcript, and thus can serve as target site for antisense oligonucleotides (ASOs)-based therapies. Indeed, our in vitro studies show the STAT6 3' untranslated region (UTR)-targeting ASO (ASO 993523) was able to reduce expression of NAB2-STAT6 fusion transcripts in multiple SFT cell models with high efficiency (half-maximal inhibitory concentration: 116-300 nM). Encouragingly, in vivo treatment of SFT patient-derived xenograft mouse models with ASO 993523 resulted in acceptable tolerability profiles, reduced expression of NAB2-STAT6 fusion transcripts in xenograft tissues (21.9%), and, importantly, reduced tumor growth (32.4% decrease in tumor volume compared with the untreated control). Taken together, our study established ASO 993523 as a potential agent for the treatment of SFTs.

CD37 is a safe chimeric antigen receptor target to treat acute myeloid leukemia

Acute myeloid leukemia (AML) is characterized by the accumulation of immature myeloid cells in the bone marrow and the peripheral blood. Nearly half of the AML patients relapse after standard induction therapy, and new forms of therapy are urgently needed. Chimeric antigen receptor (CAR) T therapy has so far not been successful in AML due to lack of efficacy and safety. Indeed, the most attractive antigen targets are stem cell markers such as CD33 or CD123. We demonstrate that CD37, a mature B cell marker, is expressed in AML samples, and its presence correlates with the European LeukemiaNet (ELN) 2017 risk stratification. We repurpose the anti-lymphoma CD37CAR for the treatment of AML and show that CD37CAR T cells specifically kill AML cells, secrete proinflammatory cytokines, and control cancer progression in vivo. Importantly, CD37CAR T cells display no toxicity toward hematopoietic stem cells. Thus, CD37 is a promising and safe CAR T cell AML target.

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

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

Simvastatin Overcomes Resistance to Tyrosine Kinase Inhibitors in Patient-derived, Oncogene-driven Lung Adenocarcinoma Models

There is an unmet clinical need to develop novel strategies to overcome resistance to tyrosine kinase inhibitors (TKI) in patients with oncogene-driven lung adenocarcinoma (LUAD). The objective of this study was to determine whether simvastatin could overcome TKI resistance using the in vitro and in vivo LUAD models. Human LUAD cell lines, tumor cells, and patient-derived xenograft (PDX) models from TKI-resistant LUAD were treated with simvastatin, either alone or in combination with a matched TKI. Tumor growth inhibition was measured by the 3-(4,5-dimethylthiazol-2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) assay and expression of molecular targets was assessed by immunoblots. Tumors were assessed by histopathology, IHC stain, immunoblots, and RNA sequencing. We found that simvastatin had a potent antitumor effect in tested LUAD cell lines and PDX tumors, regardless of tumor genotypes. Simvastatin and TKI combination did not have antagonistic cytotoxicity in these LUAD models. In an osimertinib-resistant LUAD PDX model, simvastatin and osimertinib combination resulted in a greater reduction in tumor volume than simvastatin alone (P < 0.001). Immunoblots and IHC stain also confirmed that simvastatin inhibited TKI targets. In addition to inhibiting 3-hydroxy-3-methyl-glutaryl-CoA (HMG-CoA) reductase, RNA sequencing and Western blots identified the proliferation, migration, and invasion-related genes (such as PI3K/Akt/mTOR, YAP/TAZ, focal adhesion, extracellular matrix receptor), proteasome-related genes, and integrin (α3β1, αvβ3) signaling pathways as the significantly downregulated targets in these PDX tumors treated with simvastatin and a TKI. The addition of simvastatin is a safe approach to overcome acquired resistance to TKIs in several oncogene-driven LUAD models, which deserve further investigation.

Therapeutic efficacy of RAS inhibitor trametinib using a juvenile myelomonocytic leukemia patient-derived xenograft model

Juvenile myelomonocytic leukemia (JMML) is an aggressive pediatric leukemia with few effective treatments and poor outcomes even after stem cell transplantation, the only current curative treatment. We developed a JMML patient-derived xenograft (PDX) mouse model and demonstrated the in vivo therapeutic efficacy and confirmed the target of trametinib, a RAS-RAF-MEK-ERK pathway inhibitor, in this model. A PDX model was created through transplantation of patient JMML cells into mice, up to the second generation, and successful engraftment was confirmed using flow cytometry. JMML PDX mice were treated with trametinib versus vehicle control, with a median survival of 194 days in the treatment group versus 124 days in the control group (p = 0.02). Trametinib's target as a RAS pathway inhibitor was verified by showing inhibition of ERK phosphorylation using immunoblot assays. In conclusion, trametinib monotherapy significantly prolongs survival in our JMML PDX model by inhibiting the RAS pathway. Our model can be effectively used for assessment of novel targeted treatments, including potential combination therapies, to improve JMML outcomes.

Targeting CD73 with flavonoids inhibits cancer stem cells and increases lymphocyte infiltration in a triple-negative breast cancer mouse model

Introduction

Chemotherapy remains the mainstay treatment for triple-negative breast cancer (TNBC) due to the lack of specific targets. Given a modest response of immune checkpoint inhibitors in TNBC patients, improving immunotherapy is an urgent and crucial task in this field. CD73 has emerged as a novel immunotherapeutic target, given its elevated expression on tumor, stromal, and specific immune cells, and its established role in inhibiting anti-cancer immunity. CD73-generated adenosine suppresses immunity by attenuating tumor-infiltrating T- and NK-cell activation, while amplifying regulatory T cell activation. Chemotherapy often leads to increased CD73 expression and activity, further suppressing anti-tumor immunity. While debulking the tumor mass, chemotherapy also enriches heterogenous cancer stem cells (CSC), potentially leading to tumor relapse. Therefore, drugs targeting both CD73, and CSCs hold promise for enhancing chemotherapy efficacy, overcoming treatment resistance, and improving clinical outcomes. However, safe and effective inhibitors of CD73 have not been developed as of now.

Methods

We used in silico docking to screen compounds that may be repurposed for inhibiting CD73. The efficacy of these compounds was investigated through flow cytometry, RT-qPCR, CD73 activity, cell viability, tumorsphere formation, and other in vitro functional assays. For assessment of clinical translatability, TNBC patient-derived xenograft organotypic cultures were utilized. We also employed the ovalbumin-expressing AT3 TNBC mouse model to evaluate tumor-specific lymphocyte responses.

Results

We identified quercetin and luteolin, currently used as over-the-counter supplements, to have high in silico complementarity with CD73. When quercetin and luteolin were combined with the chemotherapeutic paclitaxel in a triple-drug regimen, we found an effective downregulation in paclitaxel-enhanced CD73 and CSC-promoting pathways YAP and Wnt. We found that CD73 expression was required for the maintenance of CD44highCD24low CSCs, and co-targeting CD73, YAP, and Wnt effectively suppressed the growth of human TNBC cell lines and patient-derived xenograft organotypic cultures. Furthermore, triple-drug combination inhibited paclitaxel-enriched CSCs and simultaneously improved lymphocyte infiltration in syngeneic TNBC mouse tumors.

Discussion

Conclusively, our findings elucidate the significance of CSCs in impairing anti-tumor immunity. The high efficacy of our triple-drug regimen in clinically relevant platforms not only underscores the importance for further mechanistic investigations but also paves the way for potential development of new, safe, and cost-effective therapeutic strategies for TNBC.

Preclinical Efficacy of Cabazitaxel Loaded Poly(2-alkyl cyanoacrylate) Nanoparticle Variants

Background

Biodegradable poly(alkyl cyanoacrylate) (PACA) nanoparticles (NPs) are receiving increasing attention in anti-cancer nanomedicine development not only for targeted cancer chemotherapy, but also for modulation of the tumor microenvironment. We previously reported promising results with cabazitaxel (CBZ) loaded poly(2-ethylbutyl cyanoacrylate) NPs (PEBCA-CBZ NPs) in a patient derived xenograft (PDX) model of triple-negative breast cancer, and this was associated with a decrease in M2 macrophages. The present study aims at comparing two endotoxin-free PACA NP variants (PEBCA and poly(2-ethylhexyl cyanoacrylate); PEHCA), loaded with CBZ and test whether conjugation with folate would improve their effect.

Methods

Cytotoxicity assays and cellular uptake of NPs by flow cytometry were performed in different breast cancer cells. Biodistribution and efficacy studies were performed in PDX models of breast cancer. Tumor associated immune cells were analyzed by multiparametric flow cytometry.

Results

In vitro studies showed similar NP-induced cytotoxicity patterns despite difference in early NP internalization. On intravenous injection, the liver cleared the majority of NPs. Efficacy studies in the HBCx39 PDX model demonstrated an enhanced effect of drug-loaded PEBCA variants compared with free drug and PEHCA NPs. Furthermore, the folate conjugated PEBCA variant did not show any enhanced effects compared with the unconjugated counterpart which might be due to unfavorable orientation of folate on the NPs. Finally, analyses of the immune cell populations in tumors revealed that treatment with drug loaded PEBCA variants affected the myeloid cells, especially macrophages, contributing to an inflammatory, immune activated tumor microenvironment.

Conclusion

We report for the first time, comparative efficacy of PEBCA and PEHCA NP variants in triple negative breast cancer models and show that CBZ-loaded PEBCA NPs exhibit a combined effect on tumor cells and on the tumor associated myeloid compartment, which may boost the anti-tumor response.

A synergistic two-drug therapy specifically targets a DNA repair dysregulation that occurs in p53-deficient colorectal and pancreatic cancers

The tumor-suppressor p53 is commonly inactivated in colorectal cancer and pancreatic ductal adenocarcinoma, but existing treatment options for p53-mutant (p53Mut) cancer are largely ineffective. Here, we report a therapeutic strategy for p53Mut tumors based on abnormalities in the DNA repair response. Investigation of DNA repair upon challenge with thymidine analogs reveals a dysregulation in DNA repair response in p53Mut cells that leads to accumulation of DNA breaks. Thymidine analogs do not interrupt DNA synthesis but induce DNA repair that involves a p53-dependent checkpoint. Inhibitors of poly(ADP-ribose) polymerase (PARPis) markedly enhance DNA double-strand breaks and cell death induced by thymidine analogs in p53Mut cells, whereas p53 wild-type cells respond with p53-dependent inhibition of the cell cycle. Combinations of trifluorothymidine and PARPi agents demonstrate superior anti-neoplastic activity in p53Mut cancer models. These findings support a two-drug combination strategy to improve outcomes for patients with p53Mut cancer.

Transcriptomic, Proteomic, and Genomic Mutational Fraction Differences Based on HPV Status Observed in Patient-Derived Xenograft Models of Penile Squamous Cell Carcinoma

Metastatic penile squamous cell carcinoma (PSCC) has only a 50% response rate to first-line combination chemotherapies and there are currently no targeted-therapy approaches. Therefore, we have an urgent need in advanced-PSCC treatment to find novel therapies. Approximately half of all PSCC cases are positive for high-risk human papillomavirus (HR-HPV). Our objective was to generate HPV-positive (HPV+) and HPV-negative (HPV-) patient-derived xenograft (PDX) models and to determine the biological differences between HPV+ and HPV- disease. We generated four HPV+ and three HPV- PSCC PDX animal models by directly implanting resected patient tumor tissue into immunocompromised mice. PDX tumor tissue was found to be similar to patient tumor tissue (donor tissue) by histology and short tandem repeat fingerprinting. DNA mutations were mostly preserved in PDX tissues and similar APOBEC (apolipoprotein B mRNA editing catalytic polypeptide) mutational fractions in donor tissue and PDX tissues were noted. A higher APOBEC mutational fraction was found in HPV+ versus HPV- PDX tissues (p = 0.044), and significant transcriptomic and proteomic expression differences based on HPV status included p16 (CDKN2A), RRM2, and CDC25C. These models will allow for the direct testing of targeted therapies in PSCC and determine their response in correlation to HPV status.

Evaluating CD133 as a Radiotheranostic Target in Small-Cell Lung Cancer

Despite decades of work, small-cell lung cancer (SCLC) remains a frustratingly recalcitrant disease. Both diagnosis and treatment are challenges: low-dose computed tomography (the approved method used for lung cancer screening) is unable to reliably detect early SCLC, and the malignancy's 5 year survival rate stands at a paltry 7%. Clearly, the development of novel diagnostic and therapeutic tools for SCLC is an urgent, unmet need. CD133 is a transmembrane protein that is expressed at low levels in normal tissue but is overexpressed by a variety of tumors, including SCLC. We previously explored CD133 as a biomarker for a novel autoantibody-to-immunopositron emission tomography (PET) strategy for the diagnosis of SCLC, work that first suggested the promise of the antigen as a radiotheranostic target in the disease. Herein, we report the in vivo validation of a pair of CD133-targeted radioimmunoconjugates for the PET imaging and radioimmunotherapy of SCLC. To this end, [89Zr]Zr-DFO-αCD133 was first interrogated in a trio of advanced murine models of SCLC─i.e., orthotopic, metastatic, and patient-derived xenografts─with the PET probe consistently producing high activity concentrations (>%ID/g) in tumor lesions combined with low uptake in healthy tissues. Subsequently, a variant of αCD133 labeled with the β-emitting radiometal 177Lu─[177Lu]Lu-DTPA-A″-CHX-αCD133─was synthesized and evaluated in a longitudinal therapy study in a subcutaneous xenograft model of SCLC, ultimately revealing that treatment with a dose of 9.6 MBq of the radioimmunoconjugate produced a significant increase in median survival compared to a control cohort. Taken together, these data establish CD133 as a viable target for the nuclear imaging and radiopharmaceutical therapy of SCLC.

Thioredoxin Reductase Inhibitor Suppresses the Local Progression of Rhabdomyosarcoma With PDX Models

BACKGROUND/AIM

Chemoresistance in rhabdomyosarcoma (RMS) is associated with poor survival, necessitating the development of novel anticancer drugs. Auranofin (AUR), an anti-rheumatic drug, is a thioredoxin reductase (TXNRD) inhibitor with anticancer properties. Although patient-derived xenograft (PDX) models are essential for studying cancer biology, reports on sarcomas using the PDX model are scarce because of their rarity. This study aimed to investigate the effectiveness of AUR treatment in RMS using a PDX model to evaluate its impact on local progression.

MATERIALS AND METHODS

A 20-year-old woman who was diagnosed with alveolar RMS was used to generate the PDX model. RMS PDX tumors were implanted in nude mice and divided into non-treated (vehicle) and treated (AUR) groups. Tumor volume and weight were evaluated, and immunohistochemical staining was performed to evaluate local progression of the sarcoma. The relationship between the TXNRD-1 expression and survival probability of patients with RMS was evaluated using publicly available expression cohorts.

RESULTS

AUR significantly suppressed RMS tumor progression over time. It also significantly suppressed the tumor size and weight at the time of excision. Histological evaluation showed that AUR induced oxidative stress in the PDX mouse models and inhibited the local progression of RMS by inducing apoptosis. High TXNRD-1 expression was found to be a negative prognostic factor for overall survival in patients with RMS.

CONCLUSION

AUR-induced inhibition of TXNRDs can significantly impede the local progression of RMS through the oxidative stress-apoptosis pathway as demonstrated in PDX models. Thus, targeting TXNRD inhibition may be a promising therapeutic strategy for the treatment of RMS.

Vinorelbine Improves the Efficacy of Sorafenib against Hepatocellular Carcinoma: A Promising Therapeutic Approach

Hepatocellular carcinoma (HCC) is a leading global cause of cancer-related mortality. Despite the widespread adoption of sorafenib as the standard HCC treatment, its efficacy is constrained, frequently encountering resistance. To augment the effectiveness of sorafenib, this study investigated the synergy of sorafenib and vinorelbine using 22 HCC patient-derived xenograft (PDX) models. In this study, mice bearing HCC tumors were treated with the vehicle, sorafenib (15 mg/kg), vinorelbine (3 mg/kg), and sorafenib-vinorelbine combination (Sora/Vino). Rigorous monitoring of the tumor growth and side effects coupled with comprehensive histological and molecular analyses was conducted. The overall survival (OS) of mice bearing HCC orthotopic tumors was also assessed. Our data showed a notable 86.4% response rate to Sora/Vino, surpassing rates of 31.8% for sorafenib and 9.1% for vinorelbine monotherapies. Sora/Vino significantly inhibited tumor growth, prolonged OS of mice bearing HCC orthotopic tumors (p < 0.01), attenuated tumor cell proliferation and angiogenesis, and enhanced necrosis and apoptosis. The combination therapy effectively suppressed the focal adhesion kinase (FAK) pathway, which is a pivotal player in cell proliferation, tumor angiogenesis, survival, and metastasis. The noteworthy antitumor activity in 22 HCC PDX models positions Sora/Vino as a promising candidate for early-phase clinical trials, leveraging the established use of sorafenib and vinorelbine in HCC and other cancers.

Consistency between Primary Uterine Corpus Malignancies and Their Corresponding Patient-Derived Xenograft Models

Patient-derived xenograft (PDX) models retain the characteristics of tumors and are useful tools for personalized therapy and translational research. In this study, we aimed to establish PDX models for uterine corpus malignancies (UC-PDX) and analyze their similarities. Tissue fragments obtained from 92 patients with uterine corpus malignancies were transplanted subcutaneously into immunodeficient mice. Histological and immunohistochemical analyses were performed to compare tumors of patients with PDX tumors. DNA and RNA sequencing were performed to validate the genetic profile. Furthermore, the RNA in extracellular vesicles (EVs) extracted from primary and PDX tumors was analyzed. Among the 92 cases, 52 UC-PDX models were established, with a success rate of 56.5%. The success rate depended on tumor histology and staging. The pathological and immunohistochemical features of primary and PDX tumors were similar. DNA sequencing revealed similarities in gene mutations between the primary and PDX tumors. RNA sequencing showed similarities in gene expressions between primary and PDX tumors. Furthermore, the RNA profiles of the EVs obtained from primary and PDX tumors were similar. As UC-PDX retained the pathological and immunohistochemical features and gene profiles of primary tumors, they may provide a platform for developing personalized medicine and translational research.

Advancements and application prospects of three-dimensional models for primary liver cancer: a comprehensive review

Primary liver cancer (PLC) is one of the most commonly diagnosed cancers worldwide and a leading cause of cancer-related deaths. However, traditional liver cancer models fail to replicate tumor heterogeneity and the tumor microenvironment, limiting the study and personalized treatment of liver cancer. To overcome these limitations, scientists have introduced three-dimensional (3D) culture models as an emerging research tool. These 3D models, utilizing biofabrication technologies such as 3D bioprinting and microfluidics, enable more accurate simulation of the in vivo tumor microenvironment, replicating cell morphology, tissue stiffness, and cell-cell interactions. Compared to traditional two-dimensional (2D) models, 3D culture models better mimic tumor heterogeneity, revealing differential sensitivity of tumor cell subpopulations to targeted therapies or immunotherapies. Additionally, these models can be used to assess the efficacy of potential treatments, providing guidance for personalized therapy. 3D liver cancer models hold significant value in tumor biology, understanding the mechanisms of disease progression, and drug screening. Researchers can gain deeper insights into the impact of the tumor microenvironment on tumor cells and their interactions with the surrounding milieu. Furthermore, these models allow for the evaluation of treatment responses, offering more accurate guidance for clinical interventions. In summary, 3D models provide a realistic and reliable tool for advancing PLC research. By simulating tumor heterogeneity and the microenvironment, these models contribute to a better understanding of the disease mechanisms and offer new strategies for personalized treatment. Therefore, 3D models hold promising prospects for future PLC research.

Repurposing Metabolic Inhibitors in the Treatment of Colon Adenocarcinoma Patient-Derived Models

The effect of agonists on AMP-activated protein kinase (AMPK), mainly metformin and phenformin, has been appreciated in the treatment of multiple types of tumors. Specifically, the antitumor activity of phenformin has been demonstrated in melanomas containing the v-Raf murine sarcoma viral oncogene homolog B1 (BRAF) activating mutation. In this report, we elucidated the synergistic antitumor effects of biguanides with metabolism inhibitors on colon tumors. Phenformin with 2-deoxy-D-glucose (2DG) inhibited tumor cell growth in cancer cell lines, including HT29 cells harboring BRAF- and p53-mutations. Biochemical analyses showed that two chemotherapeutics exerted cooperative effects to reduce tumor growth through cell cycle arrest, apoptosis, and autophagy. The drugs demonstrated activity against phosphorylated ERK and the gain-of-function p53 mutant protein. To demonstrate tumor regressive effects in vivo, we established patient-derived models, including xenograft (PDX) and organoids (PDO). Co-treatment of biguanides with chemotherapeutics efficiently reduced the growth of patient-derived colon models in comparison to treatment with a single agent. These results strongly suggest that significant therapeutic advantages would be achieved by combining AMPK activators such as phenformin and cancer metabolic inhibitors such as 2DG.

Fucoxanthin Inhibits Development of Sigmoid Colorectal Cancer in a PDX Model With Alterations of Growth, Adhesion, and Cell Cycle Signals

BACKGROUND/AIM

Fucoxanthin (Fx), a dietary marine xanthophyll, exerts potent anticancer effects in various colorectal cancer (CRC) animal models. However, therapeutic effects of Fx in human cancer tissues remain unclear. A patient-derived xenograft (PDX) mouse model transplanted with cancer tissues from patients is widely accepted as the best preclinical model for evaluating the anticancer potential of drug candidates.

MATERIALS AND METHODS

Herein, we investigated the anticancer effects of Fx in PDX mice transplanted with cancer tissues derived from a patient with CRC (CRC-PDX) using LC-MS/MS- and western blot-based proteome analysis.

RESULTS

The tumor in the patient with CRC was a primary adenocarcinoma (T3N0M0, stage II) showing mutations of certain genes that were tumor protein p53 (TP53), AT-rich interaction domain 1A (ARID1A), neuroblastoma RAS viral oncogene homolog (NRAS), and PMS1 homolog 2 (PMS2). Administration of Fx significantly suppressed the tumor growth (0.6-fold) and tended to induce differentiation in CRC-PDX mice. Fx up-regulated glycanated-decorin (Gc-DCN) expression, and down-regulated Kinetochore-associated protein DSN1 homolog (DSN1), phospho(p) focal adhesion kinase (pFAK)(Tyr397), pPaxillin(Tyr31), and c-MYC involved in growth, adhesion, and/or cell cycle, in the tumors of CRC-PDX mice than in control mice. Alterations in the five proteins were consistent with those in human CRC HT-29 and HCT116 cells treated with fucoxanthinol (FxOH, a major metabolite of Fx).

CONCLUSION

Fx suppresses development of human-like CRC tissues, especially through growth, adhesion, and cell cycle signals.

Navigating relapsed hepatoblastoma: Predictive factors and surgical treatment strategy

OBJECTIVE

Hepatoblastoma (HB) is the most common primary hepatic malignancy in childhood. Relapse occurs in more than 50% of high-risk patients with a high mortality due to ineffective salvage therapies. The purpose of this study is to identify risk factors for relapsed HB and predictors of survival in a single tertiary referral center.

METHODS

A retrospective chart review showed 129 surgically treated HB patients from October 2004 to July 2020. Of the cohort, 22 patients presented with relapsed HB. Relapse was defined as re-appearance of malignancy after 4 weeks of normalized AFP and disappearance of all tumors on imaging.

RESULTS

Patients with relapsed HB had a 5-year overall survival (OS) of 45.4% compared to 93.1% in those without relapse (p = 0.001). When comparing PRETEXT IV, microvascular invasion, metastatic disease, and age on multivariate logistic regression, only PRETEXT IV was an independent risk factor for relapsed HB with an OR of 2.39 (95% CI: 1.16-4.96; p = 0.019). Mixed epithelial and mesenchymal HB (12/19, 63.2%) was the most common histology of primary tumors while pure epithelial HB (13/15, 86.6%) was the most common relapsed histology. Combination of surgical and medical therapy for relapsed disease was predictive of survival with an HR of 16.3 (95% CI: 1.783-149.091; p = 0.013) compared to only chemotherapy.

CONCLUSIONS

This study demonstrates that PRETEXT IV staging is an independent predictor of relapsed disease. The most common relapsed histology was epithelial, suggesting a potential selection or resistance of this component. Surgical resection is a critical component of multimodal therapy for relapsed HB.

ABCB1 Regulates Immune Genes in Breast Cancer

Background

Resistance to standard chemotherapy is a critical problem for breast cancer patients. The ATP-binding cassette (ABC) superfamily transporters actively pump out drugs and play an important role in chemoresistance. ABCB1 (ABC subfamily B, member 1, also named as multidrug resistance protein 1, MDR1) and suppressive myeloid-derived suppressor cells (MDSCs) potentially involve in chemoresistance of breast cancer. The relationship between ABCB1 and immune genes in breast cancer has not been widely studied.

Methods

Microarray and RNA sequencing data were obtained from The Cancer Genome Atlas Breast Invasive Carcinoma in Genomic Data Commons Data Portal and Gene Expression Omnibus database. A patient-derived xenograft (PDX) model of HER2+ breast cancer was established to investigate the association between ABCB1 and immune genes in breast cancer.

Results

Expression of ABCB1 increased in doxorubicin-selected MCF-7/ADR cells. High expression of ABCB1 mRNA is correlated with lymph-node metastasis and worse overall survival in patients with breast cancer. ABCB1 is positively correlated with IL6, CSF1, CSF3, and PTGS2. In the HER2+ stage IIA breast cancer PDX model, both doxorubicin and paclitaxel suppressed growth of P2 tumors. IL6, CSF1, CSF3, and PTGS2 expression were suppressed by paclitaxel but not doxorubicin. Intrasplenic MDSCs, including CD11b+Ly6G+ and CD11b+Ly6C+ cells, were more abundant than intratumor MDSCs in PDX-carrying nude mice. Clinically, the patient developed cancer recurrence after adjuvant chemotherapy with doxorubicin-based regimen and was well controlled after paclitaxel-trastuzumab combined therapy.

Conclusion

ABCB1 was a poor predictor of HER2+ LN- breast cancer. Regulation of immune genes by ABCB1 contributed to cancer recurrence and treatment effect. The PDX model was suitable for investigation the expression of target genes and expansion of immune cells.

Introduction of Androgen Receptor Targeting shRNA Inhibits Tumor Growth in Patient-Derived Prostate Cancer Xenografts

Patient-derived xenograft (PDX) models have been established as important preclinical cancer models, overcoming some of the limitations associated with the use of cancer cell lines. The utility of prostate cancer PDX models has been limited by an inability to genetically manipulate them in vivo and difficulties sustaining PDX-derived cancer cells in culture. Viable, short-term propagation of PDX models would allow in vitro transfection with traceable reporters or manipulation of gene expression relevant to different studies within the prostate cancer field. Here, we report an organoid culture system that supports the growth of prostate cancer PDX cells in vitro and permits genetic manipulation, substantially increasing the scope to use PDXs to study the pathobiology of prostate cancer and define potential therapeutic targets. We have established a short-term PDX-derived in vitro cell culture system which enables genetic manipulation of prostate cancer PDXs LuCaP35 and BM18. Genetically manipulated cells could be re-established as viable xenografts when re-implanted subcutaneously in immunocompromised mice and were able to be serially passaged. Tumor growth of the androgen-dependent LuCaP35 PDX was significantly inhibited following depletion of the androgen receptor (AR) in vivo. Taken together, this system provides a method to generate novel preclinical models to assess the impact of controlled genetic perturbations and allows for targeting specific genes of interest in the complex biological setting of solid tumors.

Smoking induces WEE1 expression to promote docetaxel resistance in esophageal adenocarcinoma

Esophageal adenocarcinoma (EAC) patients have poor clinical outcomes, with an overall 5-year survival rate of 20%. Smoking is a significant risk factor for EAC. The role of WEE1, a nuclear kinase that negatively regulates the cell cycle in normal conditions, in EAC tumorigenesis and drug resistance is not fully understood. Immunohistochemistry staining shows significant WEE1 overexpression in human EAC tissues. Nicotine, nicotine-derived nitrosamine ketone, or 2% cigarette smoke extract treatment induces WEE1 protein expression in EAC, detected by western blot and immunofluorescence staining. qRT-PCR and reporter assay indicates that smoking induces WEE1 expression through miR-195-5p downregulation in EAC. ATP-Glo cell viability and clonogenic assay confirmed that WEE1 inhibition sensitizes EAC cells to docetaxel treatment in vitro. A TE-10 smoking machine with EAC patient-derived xenograft mouse model demonstrated that smoking induces WEE1 protein expression and resistance to docetaxel in vivo. MK-1775 and docetaxel combined treatment improves EAC patient-derived xenograft mouse survival in vivo. Our findings demonstrate, for the first time, that smoking-induced WEE1 overexpression through miRNA dysregulation in EAC plays an essential role in EAC drug resistance. WEE1 inhibition is a promising therapeutic method to overcome drug resistance and target treatment refractory cancer cells.

Therapeutic Efficacy of Temsirolimus in a Patient-derived Model of Metastatic Fibrolamellar Hepatocellular Carcinoma

BACKGROUND/AIM

Fibrolamellar hepatocellular carcinoma (FLHCC) is a rare tumor presenting in younger patients without chronic liver disease. Up to 80-100% develop recurrent disease, necessitating additional surgery or systemic treatment. Systemic options and pre-clinical treatment studies are lacking. We previously described patient-derived xenograft (PDX) development, allowing for pre-clinical studies. Herein, we develop FLHCC PDX models and utilize these to define tumor characteristics and determine the efficacy of systemic agents.

MATERIALS AND METHODS

Primary and lymph node metastatic tumor tissues were obtained at the time of FLHCC resection in two patients. Tumor lysates were screened for protein upregulation. Cell lines were generated from metastatic and primary tumor tissue. The viability of the cell lines was assessed after treatment with temsirolimus, gemcitabine/oxaliplatin, and FOLFIRINOX. Two PDX models were developed from metastatic tissue. For in vivo studies, tumor-bearing mice were treated with temsirolimus, FOLFIRINOX, and Gemcitabine/oxaliplatin.

RESULTS

PDX models were successfully generated from metastatic FLHCC, which closely recapitulated the original tumor. Upregulation of mTOR was seen in metastatic tissue compared to primary tumors. Cell lines from metastatic tissue demonstrated significant sensitivity to temsirolimus. In vivo testing of PDX models demonstrated a significant response to single-agent temsirolimus with minimal toxicity.

CONCLUSION

Herein, we demonstrate the feasibility of developing PDX models that closely recapitulate FLHCC. Upregulation of mTOR was seen in metastatic tissue compared to primary tissue. The efficacy of mTOR inhibition with temsirolimus treatment suggests that the upregulation of the mTOR pathway may be a significant mechanism for growth in metastatic lesions and a potential target for therapeutics.

Evaluating cancer cell line and patient-derived xenograft recapitulation of tumor and non-diseased tissue gene expression profiles in silico

BACKGROUND

Preclinical models like cancer cell lines and patient-derived xenografts (PDXs) are vital for studying disease mechanisms and evaluating treatment options. It is essential that they accurately recapitulate the disease state of interest to generate results that will translate in the clinic. Prior studies have demonstrated that preclinical models do not recapitulate all biological aspects of human tissues, particularly with respect to the tissue of origin gene expression signatures. Therefore, it is critical to assess how well preclinical model gene expression profiles correlate with human cancer tissues to inform preclinical model selection and data analysis decisions.

AIMS

Here we evaluated how well preclinical models recapitulate human cancer and non-diseased tissue gene expression patterns in silico with respect to the full gene expression profile as well as subsetting by the most variable genes, genes significantly correlated with tumor purity, and tissue-specific genes.

METHODS

By using publicly available gene expression profiles across multiple sources, we evaluated cancer cell line and patient-derived xenograft recapitulation of tumor and non-diseased tissue gene expression profiles in silico.

RESULTS

We found that using the full gene set improves correlations between preclinical model and tissue global gene expression profiles, confirmed that glioblastoma (GBM) PDX global gene expression correlation to GBM tumor global gene expression outperforms GBM cell line to GBM tumor global gene expression correlations, and demonstrated that preclinical models in our study often failed to reproduce tissue-specific expression. While including additional genes for global gene expression comparison between cell lines and tissues decreases the overall correlation, it improves the relative rank between a cell line and its tissue of origin compared to other tissues. Our findings underscore the importance of using the full gene expression set measured when comparing preclinical models and tissues and confirm that tissue-specific patterns are better preserved in GBM PDX models than in GBM cell lines.

CONCLUSION

Future studies can build on these findings to determine the specific pathways and gene sets recapitulated by particular preclinical models to facilitate model selection for a given study design or goal.

Proteome-wide Profiling of Asymmetric Dimethylated Arginine in Human Breast Tumors

Arginine methylation catalyzed by protein arginine methyltransferases (PRMTs) is a prevalent post-translational modification (PTM) that regulates diverse cellular processes. Aberrant expression of type I PRMTs that catalyze asymmetric arginine dimethylation (ADMA) is often found in cancer, though little is known about the ADMA status of substrate proteins in tumors. Using LC-MS/MS along with pan-specific ADMA antibodies, we performed global mapping of ADMA in five patient-derived xenograft (PDX) tumors representing different subtypes of human breast cancer. In total, 403 methylated sites from 213 proteins were identified, including 322 novel sites when compared to the PhosphositesPlus database. Moreover, using peptide arrays in vitro, approximately 70% of the putative substrates were validated to be methylated by PRMT1, PRMT4, and PRMT6. Notably, when compared with our previously identified ADMA sites from breast cancer cell lines, only 75 ADMA sites overlapped between cell lines and PDX tumors. Collectively, this study provides a useful resource for both PRMT and breast cancer communities for further exploitation of the functions of PRMT dysregulation during breast cancer progression.

Humanized Mouse Models for Immuno-oncology Drug Discovery

Breakthroughs in cancer treatment with immunotherapeutics have provided long-term patient benefits for many different types of cancer. However, complete response is not achieved in many patients and tumor types, and the mechanisms underlying this lack of response are poorly understood. Despite this, numerous new targets, therapeutics, and drug combinations are being developed and tested in clinical trials. Preclinical models that recapitulate the complex human tumor microenvironment and the interplay between tumor and immune cells within the cancer-immunity cycle are needed to improve our understanding and screen new therapeutics for efficacy and safety/toxicity. Humanized mice, encompassing human tumors and human immune cells engrafted on immunodeficient mice, have been widely used for many years in immuno-oncology, with developments to improve both the humanization and the translational value central to the next generation of models. In this overview, we discuss recent advances in humanized models relevant to immuno-oncology drug discovery, the advantages and limitations of such models, the application of humanized models for efficacy and safety assessments of immunotherapeutics, and the potential opportunities. © 2023 Crown Bioscience. Current Protocols published by Wiley Periodicals LLC.

Generation of Orthotopic Patient-Derived Xenografts in Humanized Mice for Evaluation of Emerging Targeted Therapies and Immunotherapy Combinations for Melanoma

Current methodologies for developing PDX in humanized mice in preclinical trials with immune-based therapies are limited by GVHD. Here, we compared two approaches for establishing PDX tumors in humanized mice: (1) PDX are first established in immune-deficient mice; or (2) PDX are initially established in humanized mice; then established PDX are transplanted to a larger cohort of humanized mice for preclinical trials. With the first approach, there was rapid wasting of PDX-bearing humanized mice with high levels of activated T cells in the circulation and organs, indicating immune-mediated toxicity. In contrast, with the second approach, toxicity was less of an issue and long-term human melanoma tumor growth and maintenance of human chimerism was achieved. Preclinical trials from the second approach revealed that rigosertib, but not anti-PD-1, increased CD8/CD4 T cell ratios in spleen and blood and inhibited PDX tumor growth. Resistance to anti-PD-1 was associated with PDX tumors established from tumors with limited CD8+ T cell content. Our findings suggest that it is essential to carefully manage immune editing by first establishing PDX tumors in humanized mice before expanding PDX tumors into a larger cohort of humanized mice to evaluate therapy response.

Meckel's Diverticulum Carcinoma Is Arrested by Oxaliplatinum and Eradicated by 5-Fluorouracil in a PDX Mouse Model Indicating Candidate First-line Treatment for a Rare Cancer

BACKGROUND/AIM

Meckel's diverticulum carcinoma (MDCa) is extremely rare. It is often advanced when found, and the prognosis is poor. Effective treatment for this cancer has not yet been developed. We previously established a patient-derived xenograft (PDX) nude-mouse model of MDCa. In the present study, we investigated the efficacy of oxaliplatinum (L-OHP) and 5-fluorouracil (5-FU) on an MDCa PDX nude-mouse model.

MATERIALS AND METHODS

PDX mouse models of MDCa were divided into three groups (five mice per group): untreated control; L-OHP-treated; and 5-FU-treated. Tumor volumes of the three groups were compared after 2 weeks.

RESULTS

L-OHP arrested tumor growth (p=0.038) and 5-FU apparently eradicated the tumor (p=0.007).

CONCLUSION

L-OHP and 5-FU are candidates for clinical first-line therapy of MDCa.

Stratification of Tamoxifen Synergistic Combinations for the Treatment of ER+ Breast Cancer

Breast cancer alone accounts for the majority of cancer deaths among women, with the most commonly diagnosed subtype being estrogen receptor positive (ER+). Survival has greatly improved for patients with ER+ breast cancer, due in part to the development of antiestrogen compounds, such as tamoxifen. While treatment of the primary disease is often successful, as many as 30% of patients will experience recurrence and metastasis, mainly due to developed endocrine therapy resistance. In this study, we discovered two tamoxifen combination therapies, with simeprevir and VX-680, that reduce the tumor burden in animal models of ER+ breast cancer more than either compound or tamoxifen alone. Additionally, these tamoxifen combinations reduced the expression of HER2, a hallmark of tamoxifen treatment, which can facilitate acquisition of a treatment-resistant phenotype. These combinations could provide clinical benefit by potentiating tamoxifen treatment in ER+ breast cancer.

Prediction of pathological response grading for esophageal squamous carcinoma after neoadjuvant chemoradiotherapy based on MRI imaging using PDX

Introduction

To confirm the efficacy of magnetic resonance-diffusion weighted imaging (MR-DWI) in esophageal squamous cell carcinoma (ESCC) early pathological response prediction and assessment to neoadjuvant chemoradiotherapy (nCRT) using patient-derived xenografts (PDXs).

Methods

PDX-bearing mice were randomly divided into two groups: the experimental group receiving cisplatin combined with radiotherapy, whereas the control group receiving normal saline. MRI scans were performed in treatment groups in the before, middle, and end of treatment. The correlations between tumor volumes, ADC values and tumor pathological response at different time nodes were explored. Then, expression of proliferation marker and apoptotic marker were detected using immunohistochemistry, and apoptosis rate was detected by TUNEL assay to further verify the results observed in the PDX models.

Results

The ADC values of the experimental group were significantly higher than the control group in the both middle and end stage of treatment (all P< 0.001), however, significant difference was only observed in tumor volume at the end stage of treatment (P< 0.001). Furthermore, the △ADC_mid-pre in our study may able to identify tumors with or without pCR to nCRT at an early stage, due to these changes were prior to the changes of tumor volume after treatment. Finally, TUNEL results also showed that the apoptosis rate of the experiment groups increased the most in the middle stage of treatment, especially the groups with pCR, but the highest apoptosis rate occurred in the end of the treatment. Further, the two PDX models with pCR exhibited the highest levels of apoptotic marker (Bax), and lowest levels of proliferation marker (PCNA and Ki-67) in the both middle and end stage of the treatment.

Conclusions

ADC values could be used to determine the tumor's response to nCRT, especially in the middle stages of treatment and before the tumor tissue morphology changes, and further, the ADC values were consistent with the potential biomarkers reflecting histopathological changes. Therefore, we suggest that radiation oncologists could refer to the ADC values in the middle stages of treatment when predicting the tumor histopathological response to n CRT in patients with ESCC.

Longitudinal characterization of primary osteosarcoma and derived subcutaneous and orthotopic relapsed patient-derived xenograft models

Osteosarcoma is a rare bone cancer in adolescents and young adults with a dismal prognosis because of metastatic disease and chemoresistance. Despite multiple clinical trials, no improvement in outcome has occurred in decades. There is an urgent need to better understand resistant and metastatic disease and to generate in vivo models from relapsed tumors. We developed eight new patient-derived xenograft (PDX) subcutaneous and orthotopic/paratibial models derived from patients with recurrent osteosarcoma and compared the genetic and transcriptomic landscapes of the disease progression at diagnosis and relapse with the matching PDX. Whole exome sequencing showed that driver and copy-number alterations are conserved from diagnosis to relapse, with the emergence of somatic alterations of genes mostly involved in DNA repair, cell cycle checkpoints, and chromosome organization. All PDX patients conserve most of the genetic alterations identified at relapse. At the transcriptomic level, tumor cells maintain their ossification, chondrocytic, and trans-differentiation programs during progression and implantation in PDX models, as identified at the radiological and histological levels. A more complex phenotype, like the interaction with immune cells and osteoclasts or cancer testis antigen expression, seemed conserved and was hardly identifiable by histology. Despite NSG mouse immunodeficiency, four of the PDX models partially reconstructed the vascular and immune-microenvironment observed in patients, among which the macrophagic TREM2/TYROBP axis expression, recently linked to immunosuppression. Our multimodal analysis of osteosarcoma progression and PDX models is a valuable resource to understand resistance and metastatic spread mechanisms, as well as for the exploration of novel therapeutic strategies for advanced osteosarcoma.

Intranasal delivery of nanoliposomal SN-38 for treatment of diffuse midline glioma

OBJECTIVE

Diffuse midline gliomas, including diffuse intrinsic pontine gliomas (DIPGs), are among the most malignant and devastating childhood brain cancers. Despite aggressive treatment, nearly all children with these tumors succumb to their disease within 2 years of diagnosis. Due to the anatomical location of the tumors within the pons, surgery is not a treatment option, and distribution of most systematically administered drugs is limited by the blood-brain barrier (BBB). New drug delivery systems that bypass the BBB are desperately needed to improve outcomes of DIPG patients. Intranasal delivery (IND) is a practical and noninvasive drug delivery system that bypasses the BBB and delivers the drugs to the brain through the olfactory and trigeminal neural pathways. In this study, the authors evaluated the efficacy of nanoliposomal (LS) irinotecan (CPT-11) and an active metabolite of CPT-11, 7-ethyl-10-hydroxycamptothecin (SN-38), using IND in DIPG patient-derived xenograft models.

METHODS

In vitro responses to LS-CPT-11 and LS-SN-38 in DIPG cells were evaluated with cell viability, colony formation, and apoptosis assays. The cellular uptakes of rhodamine-PE (Rhod)-labeled LS-CPT-11 and LS-SN-38 were analyzed with fluorescence microscopy. Mice bearing DIPG patient-derived xenografts were treated with IND of LS-control (empty liposome), LS-CPT-11, or LS-SN-38 by IND for 4 weeks. In vivo responses were measured for tumor growth by serial bioluminescence imaging and animal subject survival. The concentration of SN-38 in the brainstem tumor administered by IND was determined by liquid chromatography-mass spectrometry (LC-MS). Immunohistochemical analyses of the proliferative and apoptotic responses of in vivo tumor cells were performed with Ki-67 and TUNEL staining.

RESULTS

LS-SN-38 inhibited DIPG cell growth and colony formation and increased apoptosis, outperforming LS-CPT-11. Rhod-labeled LS-SN-38 showed intracellular fluorescence signals beginning at 30 minutes and peaking at 24 hours following treatment. LC-MS analysis revealed an SN-38 concentration in the brainstem tumor of 0.66 ± 0.25 ng/ml (5.43% ± 0.31% of serum concentration). IND of LS-SN-38 delayed tumor growth and significantly prolonged animal survival compared with IND of LS-control (p < 0.0001) and LS-CPT-11 (p = 0.003). IND of LS-SN-38 increased the number of TUNEL-positive cells and decreased the Ki-67-positive cells in the brainstem tumor.

CONCLUSIONS

This study demonstrates that IND of LS-SN-38 bypasses the BBB and enables efficient and noninvasive drug delivery to the brainstem tumor, providing a promising therapeutic approach for treating DIPG.

The future of patient-derived xenografts in prostate cancer research

Patient-derived xenografts (PDXs) are generated by engrafting human tumours into mice. Serially transplantable PDXs are used to study tumour biology and test therapeutics, linking the laboratory to the clinic. Although few prostate cancer PDXs are available in large repositories, over 330 prostate cancer PDXs have been established, spanning broad clinical stages, genotypes and phenotypes. Nevertheless, more PDXs are needed to reflect patient diversity, and to study new treatments and emerging mechanisms of resistance. We can maximize the use of PDXs by exchanging models and datasets, and by depositing PDXs into biorepositories, but we must address the impediments to accessing PDXs, such as institutional, ethical and legal agreements. Through collaboration, researchers will gain greater access to PDXs representing diverse features of prostate cancer.

Viability Analysis and High-Content Live-Cell Imaging for Drug Testing in Prostate Cancer Xenograft-Derived Organoids

Tumor organoids have been pushed forward as advanced model systems for in vitro oncology drug testing, with the eventual goal to direct personalized cancer treatments. However, drug testing efforts suffer from a large variation in experimental conditions for organoid culturing and organoid treatment. Moreover, most drug tests are restricted to whole-well viability as the sole read-out, thereby losing important information about key biological aspects that might be impacted due to the use of administered drugs. These bulk read-outs also discard potential inter-organoid heterogeneity in drug responses. To tackle these issues, we developed a systematic approach for processing organoids from prostate cancer (PCa) patient-derived xenografts (PDXs) for viability-based drug testing and identified essential conditions and quality checks for consistent results. In addition, we generated an imaging-based drug testing procedure using high-content fluorescence microscopy in living PCa organoids to detect various modalities of cell death. Individual organoids and cell nuclei in organoids were segmented and quantified using a dye combination of Hoechst 33342, propidium iodide and Caspase 3/7 Green, allowing the identification of cytostatic and cytotoxic treatment effects. Our procedures provide important insights into the mechanistic actions of tested drugs. Moreover, these methods can be adapted for tumor organoids originating from other cancer types to increase organoid-based drug test validity, and ultimately, accelerate clinical implementation.

The evolution of cancer genomic medicine in Japan and the role of the National Cancer Center Japan

The journey to implement cancer genomic medicine (CGM) in oncology practice began in the 1980s, which is considered the dawn of genetic and genomic cancer research. At the time, a variety of activating oncogenic alterations and their functional significance were unveiled in cancer cells, which led to the development of molecular targeted therapies in the 2000s and beyond. Although CGM is still a relatively new discipline and it is difficult to predict to what extent CGM will benefit the diverse pool of cancer patients, the National Cancer Center (NCC) of Japan has already contributed considerably to CGM advancement for the conquest of cancer. Looking back at these past achievements of the NCC, we predict that the future of CGM will involve the following: 1) A biobank of paired cancerous and non-cancerous tissues and cells from various cancer types and stages will be developed. The quantity and quality of these samples will be compatible with omics analyses. All biobank samples will be linked to longitudinal clinical information. 2) New technologies, such as whole-genome sequencing and artificial intelligence, will be introduced and new bioresources for functional and pharmacologic analyses (e.g., a patient-derived xenograft library) will be systematically deployed. 3) Fast and bidirectional translational research (bench-to-bedside and bedside-to-bench) performed by basic researchers and clinical investigators, preferably working alongside each other at the same institution, will be implemented; 4) Close collaborations between academia, industry, regulatory bodies, and funding agencies will be established. 5) There will be an investment in the other branch of CGM, personalized preventive medicine, based on the individual's genetic predisposition to cancer.

Advances in preclinical models of prostate cancer for research discovery

There is longstanding interest in the role of androgens in the aetiology of prostate cancer, one of the most common malignancies worldwide. In this review, we reflect on the ways that knowledge of prostate development and hormone action have catalysed advances in the management of patients with prostate cancer. The use of hormone therapies to treat prostate cancer has changed significantly over time, including the emergence of androgen receptor signalling inhibitors (ARSI). These compounds have improved outcomes for patients with castration-resistant prostate cancer, which was once considered 'androgen-independent' but is clearly still driven by androgen receptor signalling in many cases. There is also a need for new therapies to manage neuroendocrine prostate cancer, which is not responsive to hormonal agents. One of the major gaps is understanding how treatment-induced neuroendocrine prostate cancer emerges and whether it can be re-sensitised to treatment. Patient-derived models, including patient-derived xenografts (PDXs), will be instrumental in facilitating future discoveries in these areas. Developments in the use of PDXs have been fostered by lessons from the field of endocrinology, such as the role of stroma and hormones in normal and developmental tissues. Thus, there is ongoing reciprocity between the discoveries in endocrinology and advances in prostate cancer research and treatment.

A Novel Hydrogel-Based 3D In Vitro Tumor Panel of 30 PDX Models Incorporates Tumor, Stromal and Immune Cell Compartments of the TME for the Screening of Oncology and Immuno-Therapies

Human-relevant systems that mimic the 3D tumor microenvironment (TME), particularly the complex mechanisms of immuno-modulation in the tumor stroma, in a reproducible and scalable format are of high interest for the drug discovery industry. Here, we describe a novel 3D in vitro tumor panel comprising 30 distinct PDX models covering a range of histotypes and molecular subtypes and cocultured with fibroblasts and PBMCs in planar (flat) extracellular matrix hydrogels to reflect the three compartments of the TME-tumor, stroma, and immune cells. The panel was constructed in a 96-well plate format and assayed tumor size, tumor killing, and T-cell infiltration using high-content image analysis after 4 days of treatment. We screened the panel first against the chemotherapy drug Cisplatin to demonstrate feasibility and robustness, and subsequently assayed immuno-oncology agents Solitomab (CD3/EpCAM bispecific T-cell engager) and the immune checkpoint inhibitors (ICIs) Atezolizumab (anti-PDL1), Nivolumab (anti-PD1) and Ipilimumab (anti-CTLA4). Solitomab displayed a strong response across many PDX models in terms of tumor reduction and killing, allowing for its subsequent use as a positive control for ICIs. Interestingly, Atezolizumab and Nivolumab demonstrated a mild response compared to Ipilimumab in a subset of models from the panel. We later determined that PBMC spatial proximity in the assay setup was important for the PD1 inhibitor, hypothesizing that both duration and concentration of antigen exposure may be critical. The described 30-model panel represents a significant advancement toward screening in vitro models of the tumor microenvironment that include tumor, fibroblast, and immune cell populations in an extracellular matrix hydrogel, with robust and standardized high content image analysis in a planar hydrogel. The platform is aimed at rapidly screening various combinations and novel agents and forming a critical conduit to the clinic, thus accelerating drug discovery for the next generation of therapeutics.

Application of Drug Testing Platforms in Circulating Tumor Cells and Validation of a Patient-Derived Xenograft Mouse Model in Patient with Primary Intracranial Ependymomas with Extraneural Metastases

Primary intracranial ependymoma is a challenging tumor to treat despite the availability of multidisciplinary therapeutic modalities, including surgical resection, radiotherapy, and adjuvant chemotherapy. After the completion of initial treatment, when resistant tumor cells recur, salvage therapy needs to be carried out with a more precise strategy. Circulating tumor cells (CTCs) have specifically been detected and validated for patients with primary or recurrent diffused glioma. The CTC drug screening platform can be used to perform a mini-invasive liquid biopsy for potential drug selection. The validation of potential drugs in a patient-derived xenograft (PDX) mouse model based on the same patient can serve as a preclinical testing platform. Here, we present the application of a drug testing model in a six-year-old girl with primary ependymoma on the posterior fossa, type A (EPN-PFA). She suffered from tumor recurrence with intracranial and spinal seeding at 2 years after her first operation and extraneural metastases in the pleura, lung, mediastinum, and distant femoral bone at 4 years after initial treatment. The CTC screening platform results showed that everolimus and entrectinib could be used to decrease CTC viability. The therapeutic efficacy of these two therapeutic agents has also been validated in a PDX mouse model from the same patient, and the results showed that these two therapeutic agents significantly decreased tumor growth. After precise drug screening and the combination of focal radiation on the femoral bone with everolimus chemotherapy, the whole-body bone scan showed significant shrinkage of the metastatic tumor on the right femoral bone. This novel approach can combine liquid biopsy, CTC drug testing platforms, and PDX model validation to achieve precision medicine in rare and challenging tumors with extraneural metastases.

Patient-derived xenograft mouse models to investigate tropism to the central nervous system and retina of primary and secondary central nervous system lymphoma

AIMS

How and why lymphoma cells home to the central nervous system and vitreoretinal compartment in primary diffuse large B-cell lymphoma of the central nervous system remain unknown. Our aim was to create an in vivo model to study lymphoma cell tropism to the central nervous system.

METHODS

We established a patient-derived central nervous system lymphoma xenograft mouse model and characterised xenografts derived from 4 primary and 4 secondary central nervous system lymphoma patients using immunohistochemistry, flow cytometry and nucleic acid sequencing technology. In reimplantation experiments, we analysed dissemination patterns of orthotopic and heterotopic xenografts and performed RNA sequencing of different involved organs to detect differences at the transcriptome level.

RESULTS

We found that xenografted primary central nervous system lymphoma cells home to the central nervous system and eye after intrasplenic transplantation, mimicking central nervous system and primary vitreoretinal lymphoma pathology, respectively. Transcriptomic analysis revealed distinct signatures for lymphoma cells in the brain in comparison to the spleen as well as a small overlap of commonly regulated genes in both primary and secondary central nervous system lymphoma.

CONCLUSION

This in vivo tumour model preserves key features of primary and secondary central nervous system lymphoma and can be used to explore critical pathways for the central nervous system and retinal tropism with the goal to find new targets for novel therapeutic approaches.

Discovering Synergistic Compounds with BYL-719 in PI3K Overactivated Basal-like PDXs

Basal-like triple-negative breast cancer (TNBC) tumor cells are difficult to eliminate due to resistance mechanisms that promote survival. While this breast cancer subtype has low PIK3CA mutation rates when compared to estrogen receptor-positive (ER+) breast cancers, most basal-like TNBCs have an overactive PI3K pathway due to gene amplification or high gene expression. BYL-719 is a PIK3CA inhibitor that has been found to have low drug-drug interactions, which increases the likelihood that it could be useful for combinatorial therapy. Alpelisib (BYL-719) with fulvestrant was recently approved for treating ER+ breast cancer patients whose cancer had developed resistance to ER-targeting therapy. In these studies, a set of basal-like patient-derived xenograft (PDX) models was transcriptionally defined with bulk and single-cell RNA-sequencing and clinically actionable mutation profiles defined with Oncomine mutational profiling. This information was overlaid onto therapeutic drug screening results. BYL-719-based, synergistic two-drug combinations were identified with 20 different compounds, including everolimus, afatinib, and dronedarone, which were also found to be effective at minimizing tumor growth. These data support the use of these drug combinations towards cancers with activating PIK3CA mutations/gene amplifications or PTEN deficient/PI3K overactive pathways.

Establishment of patient-derived xenografts of retinoblastoma and choroidal melanoma on the avian chorioallantoic membrane

Purpose

To develop a viable in vivo chorioallantoic membrane (CAM) model to study the growth and invasion of patient-derived retinoblastoma (RB) and choroidal melanoma (CM) xenografts (PDXs). The study utilizes primary tumor samples instead of cancer cell lines, which provides a more authentic representation of tumors due to conserved morphology and heterogeneity.

Methods

Fertilized chicken eggs were procured, windowed, and their CAM layers were dropped. On embryonic development day (EDD) 10, freshly cut patient-derived CM and RB tumors were implanted on the CAM layer and the setup was incubated for 7 days. The tumor-embedded CAM layer was harvested on EDD 17, and the extracted tumor samples were subjected to hematoxylin and eosin staining and immunohistochemical analysis to evaluate the extent of tumor invasion.

Results

Significant changes in the vascularity around the RB and CM PDXs were observed, indicating an angiogenic environment. The cross-sectional histological view of the tumor implant site revealed the invasion of both the tumors into the CAM mesoderm. Invasion of CM into CAM mesoderm was visualized in the form of pigmented nodules, and that of RB was indicated by synaptophysin and Ki-67 positivity in Immunohistochemistry (IHC).

Conclusion

The CAM xenograft model was successfully able to support the growth of CM and RB PDXs and their invasion in CAM, thus presenting as a feasible alternative to mammalian models for studying tumorigenicity and invasiveness of ocular tumors. Moreover, this model can further be utilized to develop personalized medicine by inoculating patient-specific tumors for preclinical drug screening.

Chick Chorioallantoic Membrane as a Patient-Derived Xenograft Model for Uveal Melanoma: Imaging Modalities for Growth and Vascular Evaluation

BACKGROUND

Patient-derived tumor xenografts (PDXs) have emerged as valuable preclinical in vivo models in oncology as they largely retain the polygenomic architecture of the human tumors from which they originate. Although animal models are accompanied by cost and time constraints and a low engraftment rate, PDXs have primarily been established in immunodeficient rodent models for the in vivo assessment of tumor characteristics and of novel therapeutic cancer targets. The chick chorioallantoic membrane (CAM) assay represents an attractive alternative in vivo model that has long been used in the research of tumor biology and angiogenesis, and can overcome some of these limitations.

METHODS

In this study, we reviewed different technical approaches for the establishment and monitoring of a CAM-based uveal melanoma PDX model. Forty-six fresh tumor grafts were acquired after enucleation from six uveal melanoma patients and were implanted onto the CAM on ED7 with Matrigel and a ring (group 1), with Matrigel (group 2), or natively without Matrigel or a ring (group 3). Real-time imaging techniques, such as various ultrasound modalities, optical coherence tomography, infrared imaging, and imaging analyses with Image J for tumor growth and extension, as well as color doppler, optical coherence angiography, and fluorescein angiography for angiogenesis, were performed on ED18 as alternative monitoring instruments. The tumor samples were excised on ED18 for histological assessment.

RESULTS

There were no significant differences between the three tested experimental groups regarding the length and width of the grafts during the development period. A statistically significant increase in volume (p = 0.0007) and weight (p = 0.0216) between ED7 and ED18 was only documented for tumor specimens of group 2. A significant correlation of the results for the cross-sectional area, largest basal diameter, and volume was documented between the different imaging and measurement techniques and the excised grafts. The formation of a vascular star around the tumor and of a vascular ring on the base of the tumor was observed for the majority of the viable developing grafts as a sign of successful engraftment.

CONCLUSION

The establishment of a CAM-PDX uveal melanoma model could elucidate the biological growth patterns and the efficacy of new therapeutic options in vivo. The methodological novelty of this study, investigating different implanting techniques and exploiting advances in real-time imaging with multiple modalities, allows precise, quantitative assessment in the field of tumor experimentation, underlying the feasibility of CAM as an in vivo PDX model.

Identification of the α2 chain of interleukin-13 receptor as a potential biomarker for predicting castration resistance of prostate cancer using patient-derived xenograft models

BACKGROUND

Several treatment strategies use upfront chemotherapy or androgen receptor axis-targeting therapies for metastatic prostate cancer. However, there are no useful biomarkers for selecting appropriate patients who urgently require these treatments.

METHODS

Novel patient-derived xenograft (PDX) castration-sensitive and -resistant models were established and gene expression patterns were comprehensively compared. The function of a gene highly expressed in the castration-resistant models was evaluated by its overexpression in LNCaP prostate cancer cells. Protein expression in the tumors and serum of patients was examined by immunohistochemistry and ELISA, and correlations with castration resistance were analyzed.

RESULTS

Expression of the α2 chain of interleukin-13 receptor (IL13Rα2) was higher in castration-resistant PDX tumors. LNCaP cells overexpressing IL13Rα2 acquired castration resistance in vitro and in vivo. In tissue samples, IL13Rα2 expression levels were significantly associated with castration-resistant progression (p < 0.05). In serum samples, IL13Rα2 levels could be measured in 5 of 28 (18%) castration-resistant prostate cancer patients.

CONCLUSION

IL13Rα2 was highly expressed in castration-resistant prostate cancer PDX models and was associated with the castration resistance of prostate cancer cells. It might be a potential tissue and serum biomarker for predicting castration resistance in prostate cancer patients.

Current status and clinical application of patient-derived tumor organoid model in kidney and prostate cancers

Urological cancers such as kidney, bladder, prostate, and testicular cancers are the most common types of cancers worldwide with high mortality and morbidity. To date, traditional cell lines and animal models have been broadly used to study pre-clinical applications and underlying molecular mechanisms of urological cancers. However, they cannot reflect biological phenotypes of real tissues and clinical diversities of urological cancers in vitro system. In vitro models cannot be utilized to reflect the tumor microenvironment or heterogeneity. Cancer organoids in three-dimensional culture have emerged as a promising platform for simulating tumor microenvironment and revealing heterogeneity. In this review, we summarize recent advances in prostate and kidney cancer organoids regarding culture conditions, advantages, and applications of these cancer organoids. [BMB Reports 2023; 56(1): 24-31].

Patient-derived models: Advanced tools for precision medicine in neuroblastoma

Neuroblastoma is a childhood cancer derived from the sympathetic nervous system. High-risk neuroblastoma patients have a poor overall survival and account for ~15% of childhood cancer deaths. There is thus a need for clinically relevant and authentic models of neuroblastoma that closely resemble the human disease to further interrogate underlying mechanisms and to develop novel therapeutic strategies. Here we review recent developments in patient-derived neuroblastoma xenograft models and in vitro cultures. These models can be used to decipher mechanisms of metastasis and treatment resistance, for drug screening, and preclinical drug testing. Patient-derived neuroblastoma models may also provide useful information about clonal evolution, phenotypic plasticity, and cell states in relation to neuroblastoma progression. We summarize current opportunities for, but also barriers to, future model development and application. Integration of patient-derived models with patient data holds promise for the development of precision medicine treatment strategies for children with high-risk neuroblastoma.

A novel preclinical model of craniospinal irradiation in pediatric diffuse midline glioma demonstrates decreased metastatic disease

Background

Diffuse midline glioma (DMG) is an aggressive pediatric central nervous system tumor with strong metastatic potential. As localized treatment of the primary tumor improves, metastatic disease is becoming a more important factor in treatment. We hypothesized that we could model craniospinal irradiation (CSI) through a DMG patient-derived xenograft (PDX) model and that CSI would limit metastatic tumor.

Methods

We used a BT245 murine orthotopic DMG PDX model for this work. We developed a protocol and specialized platform to deliver craniospinal irradiation (CSI) (4 Gy x2 days) with a pontine boost (4 Gy x2 days) and compared metastatic disease by pathology, bioluminescence, and MRI to mice treated with focal radiation only (4 Gy x4 days) or no radiation.

Results

Mice receiving CSI plus boost showed minimal spinal and brain leptomeningeal metastatic disease by bioluminescence, MRI, and pathology compared to mice receiving radiation to the pons only or no radiation.

Conclusion

In a DMG PDX model, CSI+boost minimizes tumor dissemination compared to focal radiation. By expanding effective DMG treatment to the entire neuraxis, CSI has potential as a key component to combination, multimodality treatment for DMG designed to achieve long-term survival once novel therapies definitively demonstrate improved local control.

Current status and clinical application of patient-derived tumor organoid model in kidney and prostate cancers

Urological cancers such as kidney, bladder, prostate, and testicular cancers are the most common types of cancers worldwide with high mortality and morbidity. To date, traditional cell lines and animal models have been broadly used to study pre-clinical applications and underlying molecular mechanisms of urological cancers. However, they cannot reflect biological phenotypes of real tissues and clinical diversities of urological cancers in vitro system. In vitro models cannot be utilized to reflect the tumor microenvironment or heterogeneity. Cancer organoids in three-dimensional culture have emerged as a promising platform for simulating tumor microenvironment and revealing heterogeneity. In this review, we summarize recent advances in prostate and kidney cancer organoids regarding culture conditions, advantages, and applications of these cancer organoids. [BMB Reports 2023; 56(1): 24-31].

Repurposed benzydamine targeting CDK2 suppresses the growth of esophageal squamous cell carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the leading causes of cancer death worldwide. It is urgent to develop new drugs to improve the prognosis of ESCC patients. Here, we found benzydamine, a locally acting non-steroidal anti-inflammatory drug, had potent cytotoxic effect on ESCC cells. Benzydamine could suppress ESCC proliferation in vivo and in vitro. In terms of mechanism, CDK2 was identified as a target of benzydamine by molecular docking, pull-down assay and in vitro kinase assay. Specifically, benzydamine inhibited the growth of ESCC cells by inhibiting CDK2 activity and affecting downstream phosphorylation of MCM2, c-Myc and Rb, resulting in cell cycle arrest. Our study illustrates that benzydamine inhibits the growth of ESCC cells by downregulating the CDK2 pathway.

A Genomically and Clinically Annotated Patient-Derived Xenograft Resource for Preclinical Research in Non-Small Cell Lung Cancer

Patient-derived xenograft (PDX) models are an effective preclinical in vivo platform for testing the efficacy of novel drugs and drug combinations for cancer therapeutics. Here we describe a repository of 79 genomically and clinically annotated lung cancer PDXs available from The Jackson Laboratory that have been extensively characterized for histopathologic features, mutational profiles, gene expression, and copy-number aberrations. Most of the PDXs are models of non-small cell lung cancer (NSCLC), including 37 lung adenocarcinoma (LUAD) and 33 lung squamous cell carcinoma (LUSC) models. Other lung cancer models in the repository include four small cell carcinomas, two large cell neuroendocrine carcinomas, two adenosquamous carcinomas, and one pleomorphic carcinoma. Models with both de novo and acquired resistance to targeted therapies with tyrosine kinase inhibitors are available in the collection. The genomic profiles of the LUAD and LUSC PDX models are consistent with those observed in patient tumors from The Cancer Genome Atlas and previously characterized gene expression-based molecular subtypes. Clinically relevant mutations identified in the original patient tumors were confirmed in engrafted PDX tumors. Treatment studies performed in a subset of the models recapitulated the responses expected on the basis of the observed genomic profiles. These models therefore serve as a valuable preclinical platform for translational cancer research.

SIGNIFICANCE

Patient-derived xenografts of lung cancer retain key features observed in the originating patient tumors and show expected responses to treatment with standard-of-care agents, providing experimentally tractable and reproducible models for preclinical investigations.

Sabizabulin, a Potent Orally Bioavailable Colchicine Binding Site Agent, Suppresses HER2+ Breast Cancer and Metastasis

HER2+ breast cancer accounts for 15% of all breast cancer cases. Current frontline therapy for HER2+ metastatic breast cancer relies on targeted antibodies, trastuzumab and pertuzumab, combined with microtubule inhibitors in the taxane class (paclitaxel or docetaxel). It is well known that the clinical efficacy of taxanes is limited by the development of chemoresistance and hematological and neurotoxicities. The colchicine-binding site inhibitors (CBSIs) are a class of promising alternative agents to taxane therapy. Sabizabulin (formerly known as VERU-111) is a potent CBSI that overcomes P-gp-mediated taxane resistance, is orally bioavailable, and inhibits tumor growth and distant metastasis in triple negative breast cancer (TNBC). Herein, we demonstrate the efficacy of sabizabulin in HER2⁺ breast cancer. In vitro, sabizabulin inhibits the proliferation of HER2+ breast cancer cell lines with low nanomolar IC₅₀ values, inhibits clonogenicity, and induces apoptosis in a concentration-dependent manner. In vivo, sabizabulin inhibits breast tumor growth in the BT474 (ER+/PR+/HER2+) xenograft model and a HER2+ (ER-/PR-) metastatic patient-derived xenograft (PDX) model, HCI-12. We demonstrate that sabizabulin is a promising alternative agent to target tubulin in HER2+ breast cancer with similar anti-metastatic efficacy to paclitaxel, but with the advantage of oral bioavailability and lower toxicity than taxanes.

Plocabulin, a Novel Tubulin Inhibitor, Has Potent Antitumour Activity in Patient-Derived Xenograft Models of Soft Tissue Sarcoma

A clinically relevant subset of patients with soft tissue sarcoma presents with either locally advanced or upfront metastatic disease, or will develop distant metastases over time, despite successful treatment of their primary tumour. The currently available systemic agents to treat such advanced cases only provide modest disease control and are not active in all histological subtypes. Thus, there is an unmet need for novel and more efficacious agents to improve the outcome of this rare disease. In the current preclinical in vivo study, we evaluated plocabulin, a novel tubulin inhibitor, in five distinct histological subtypes of soft tissue sarcoma: dedifferentiated liposarcoma, leiomyosarcoma, undifferentiated sarcoma, intimal sarcoma and CIC-rearranged sarcoma. The efficacy was tested in seven patient-derived xenograft models, which were generated by the engraftment of tumour fragments from patients directly into nude mice. The treatment lasted 22 days, and the efficacy of the drug was assessed and compared to the doxorubicin and vehicle groups by volumetric analysis, histopathology and immunohistochemistry. We observed tumour volume control in all the tested histological subtypes. Additionally, in three sarcoma subtypes, extensive central necrosis, associated with significant tumour regression, was seen. This histological response is explained by the drug’s vascular-disruptive properties, reflected by a decreased total vascular area in the xenografts. Our results demonstrate the in vivo efficacy of plocabulin in the preclinical models of soft tissue sarcoma and corroborate the findings of our previous study, which demonstrated similar vascular-disruptive effects in gastrointestinal stromal tumours—another subtype of soft tissue sarcoma. Our data provide a convincing rationale for further clinical exploration of plocabulin in soft tissue sarcomas.