Metastatic Cancer Model Research Articles

Artificial Diets with Altered Levels of Sulfur Amino Acids Induce Anticancer Activity in Mice with Metastatic Colon Cancer, Ovarian Cancer and Renal Cell Carcinoma.

Sulfur-containing amino acids methionine (Met), cysteine (Cys) and taurine (Tau) are common dietary constituents with important cellular roles. Met restriction is already known to exert in vivo anticancer activity. However, since Met is a precursor of Cys and Cys produces Tau, the role of Cys and Tau in the anticancer activity of Met-restricted diets is poorly understood. In this work, we screened the in vivo anticancer activity of several Met-deficient artificial diets supplemented with Cys, Tau or both. Diet B1 (6% casein, 2.5% leucine, 0.2% Cys and 1% lipids) and diet B2B (6% casein, 5% glutamine, 2.5% leucine, 0.2% Tau and 1% lipids) showed the highest activity and were selected for further studies. Both diets induced marked anticancer activity in two animal models of metastatic colon cancer, which were established by injecting CT26.WT murine colon cancer cells in the tail vein or peritoneum of immunocompetent BALB/cAnNRj mice. Diets B1 and B2B also increased survival of mice with disseminated ovarian cancer (intraperitoneal ID8 Tp53-/- cells in C57BL/6JRj mice) and renal cell carcinoma (intraperitoneal Renca cells in BALB/cAnNRj mice). The high activity of diet B1 in mice with metastatic colon cancer may be useful in colon cancer therapy.

Cancer cell eradication in a 6D metastatic tumor model with time delay

In this paper we study ultimate dynamics of one time delay cancer metastatic 6D model with chemotherapy. This model describes interactions between normal and cancer cells under chemotherapy agents that occurs in two tumor sites, primary and secondary. We derive ultimate upper bounds for normal and cancer cells; ultimate upper/lower bounds for the chemical concentration in the both of tumor sites and describe the location of the attracting set. The study of equilibrium points is included. Global asymptotic tumor eradication conditions are obtained by a two-step process. Firstly, using the localization method of compact invariant sets (LMCIS) we find conditions of the tumor clearance at the primary site. Further, exploiting the cascade structure of the whole system and properties of asymptotically autonomous and competitive systems we derive tumor eradication conditions at the secondary site under the assumption that cancer cells at the primary site are asymptotically eradicated. Based on these results, cancer eradication conditions of the whole system are obtained. In particular, it is shown that the ω-limit set of each trajectory starting in the nonnegative orthant is one of equilibrium points located in the plane which is free from both primary and secondary cancer cells.

Blood-tumor barrier opening by MRI-guided transcranial focused ultrasound in a preclinical breast cancer brain metastasis model improves efficacy of combinatorial chemotherapy.

Patients with metastatic breast cancer have high and continually increasing rates of brain metastases. During the course of the disease, brain metastases can occur in up to 30% of these patients. In most cases, brain metastases are diagnosed after significant disease progression. The blood-tumor barrier increases the difficulty of treating brain metastasis by preventing accumulation of chemotherapy within metastases at therapeutically effective concentrations. Traditional therapies, such as surgical resection, radiotherapy, and chemotherapy, have poor efficacy, as reflected by a low median survival rate of 5-8% after post-diagnosis. Low-intensity focused ultrasound (LiFUS) is a new treatment for enhancing drug accumulation within the brain and brain malignancies. In this study, we elucidate the effect of clinical LiFUS combined with chemotherapy on tumor survival and progression in a preclinical model of triple-negative breast cancer metastasis to the brain. LiFUS significantly increased the tumor accumulation of 14C-AIB and Texas Red compared to controls (p< 0.01). LiFUS-mediated opening of the BTB is size-dependent, which is consistent with our previous studies. Mice receiving LiFUS with combinatorial Doxil and paclitaxel showed a significant increase in median survival (60 days) compared to other groups. LiFUS plus combinatorial chemotherapy of paclitaxel and Doxil also showed the slowest progression of tumor burden compared to chemotherapy alone or individual chemotherapy and LiFUS combinations. This study shows that combining LiFUS with timed combinatorial chemotherapeutic treatment is a potential strategy for improving drug delivery to brain metastases.

Advancements in melanoma cancer metastasis models.

Metastatic melanoma is a complex and deadly disease. Due to its complexity, the development of novel therapeutic strategies to inhibit metastatic melanoma remains an outstanding challenge. Our ability to study metastasis is advanced with the development of in vitro and in vivo models that better mimic the different steps of the metastatic cascade beginning from primary tumor initiation to final metastatic seeding. In this review, we provide a comprehensive summary of in vitro models, in vivo models, and in silico platforms to study the individual steps of melanoma metastasis. Furthermore, we highlight the advantages and limitations of each model and discuss the challenges of how to improve current models to enhance translation for melanoma cancer patients and future therapies.

Inhibition of CXCR4 Enhances the Efficacy of Radiotherapy in Metastatic Prostate Cancer Models.

Radiotherapy (RT) is a standard treatment for patients with advanced prostate cancer (PCa). Previous preclinical studies showed that SDF1α/CXCR4 axis could mediate PCa metastasis (most often to the bones) and cancer resistance to RT. We found high levels of expression for both SDF1α and its receptor CXCR4 in primary and metastatic PCa tissue samples. In vitro analyses using PCa cells revealed an important role of CXCR4 in cell invasion but not radiotolerance. Pharmacologic inhibition of CXCR4 using AMD3100 showed no efficacy in orthotopic primary and bone metastatic PCa models. However, when combined with RT, AMD3100 potentiated the effect of local single-dose RT (12 Gy) in both models. Moreover, CXCR4 inhibition also reduced lymph node metastasis from primary PCa. Notably, CXCR4 inhibition promoted the normalization of bone metastatic PCa vasculature and reduced tissue hypoxia. In conclusion, the SDF1α/CXCR4 axis is a potential therapeutic target in metastatic PCa patients treated with RT.

Construction of a predictive model for breast cancer metastasis based on lncRNAs.

There is currently a lack of biological markers to determine the risk of lymph node metastasis in breast cancer. A single long non-coding RNA (lncRNA) cannot accurately describe the heterogeneity of tumors. Thus, more accurate algorithms are needed to screen key pathogenic lncRNAs, and quantitative models are needed to describe the heterogeneity of breast cancer. A whole transcriptome sequencing data set of breast cancer tissue samples was downloaded from The Cancer Genome Atlas database (n=1,091). A weighted correlation network analysis was conducted to identify the hub lncRNAs associated with lymph node metastasis. A logistic regression analysis was conducted to construct the risk score model. The relationship between the risk scores and the key lncRNAs and the infiltration of the immune cell subtypes was also explored. A total of 3 common lncRNAs were identified between the differentially expressed lncRNA set and the hub lncRNA set; that is, zinc finger protein 582-antisense RNA 1 (ZNF582-AS1), metastasis-associated lung adenocarcinoma transcript 1 (MALAT1), and actin filament associated protein 1-antisense RNA 1 (AFAP1-AS1). The following formula was used to calculate the risk score: risk score =1.31 + 0.51 * ZNF582-AS1 - 0.66 * MALAT1 - 0.50 * AFAP1-AS1. The receiver operating characteristic curve showed that the areas under the curve for the risk score, ZNF582-AS1, MALAT1, and AFAP1-AS1 were 0.975, 0.793, 0.685, and 0764, respectively (P<0.05). The risk score was positively correlated with immune cell subtype infiltration. ZNF582-AS1, MALAT1, and AFAP1-AS1 are the key lncRNAs involved in the lymph node metastasis of breast cancer. Our risk score model, which was based on ZNF582-AS1, MALAT1 and AFAP1-AS1, can accurately predict the risk of breast cancer lymph node metastasis. ZNF582-AS1, MALAT1, and AFAP1-AS1 are potential biomarkers for the lymph node metastasis of breast cancer.

In vitro 3D microfluidic peritoneal metastatic colorectal cancer model for testing different Oxaliplatin based HIPEC regimens

In vitro 3D microfluidic peritoneal metastatic colorectal cancer model for testing different Oxaliplatin based HIPEC regimens

Chemosensor with Ultra-High Fluorescence Enhancement for Assisting in Diagnosis and Resection of Ovarian Cancer.

Fluorescence imaging-guided diagnostics is one of the most promising approaches for facile detection of tumors in situ owing to its simple operation and non-invasiveness. As a crucial biomarker for primary ovarian cancers, β-galactosidase (β-gal) has been demonstrated to be the significant molecular target for visualization of ovarian tumors. Herein, a membrane-permeable fluorescent chemosensor (namely, LAN-βgal) was synthesized for β-gal-specific detection using the d-galactose residue as a specific recognition unit and LAN-OH (ΦF = 0.47) as a fluorophore. After β-gal was digested, the fluorescence of the initially quenched LAN-βgal (ΦF < 0.001) was enhanced by up to more than 2000-fold, which exceeded the fluorescence enhancement of other previously reported probes. We also demonstrated that the chemosensor LAN-βgal could visualize endogenous β-gal and distinguish ovarian cancer cells from normal ovarian cells. Further, the chemosensor LAN-βgal was successfully applied to visualize the back tumor-bearing mouse model and peritoneal metastatic ovarian cancer model in vivo. More importantly, through in situ spraying, the proposed chemosensor was successfully employed to assist in the surgical resection of ovarian cancer tumors due to its high tumor-to-normal (T/N) tissue fluorescence ratio of 218. To the best of our knowledge, this is the highest T/N tissue fluorescence ratio ever reported. We believe that the LAN-βgal chemosensor can be utilized as a new tool for the clinical diagnosis and treatment of ovarian cancer.

Abstract B050: Reproducible and effective preclinical models of prostate cancer metastasis established with PDXs

Abstract Metastatic castration resistant prostate cancer (mCRPC) is a lethal disease. Understanding the intricacy of this disease and developing targeted treatment is hampered by the lacking of clinically relevant animal models. LuCaP patient-derived xenografts (PDXs), established from advanced metastatic prostate cancer, are a large cohort that encompass the molecular and cellular heterogeneity of mCRPC. We have established four prostate cancer metastasis models from three androgen receptor (AR) positive lines (LuCaP136, LuCaP167 and LuCaP23.1) and one AR negative line LuCap145.2. The three AR positive LuCap lines metastasized to vertebrae and long bones with differing bone-associated histology while the AR negative LuCap145.2 metastasize to brain and spinal cord. The bone metastasis phenotypes of the models encompass: osteolytic (LuCaP136), mixed bone destruction and new bone formation (LuCaP167), and a highly osteoblastic histology (LuCaP23.1). LuCap136 and LuCap167 also metasize to soft tissues including adrenal, kidney and liver. Castration responses were studied on LuCap136 and LuCap167 models. Although both models are castration resistant, LuCap136 model initially are sensitive to castration with decreased tumor progression, and AR down-regulated in the metastatic sites. In contrast, tumor progression was not affected after castration in LuCap167 model. AR and ARV7 were up-regulated in metastatic cells. In summary, the LuCap PDX lines have the capacity for systemic growth in clinically accurate metastatic sites. In addition, the two AR positive models show different castration response which may be driven by different pathways. Understanding the complexity of these pathways would guide optimal selection of drug combinations to achieve the best outcome for patients with mCRPC. Citation Format: JuanJuan I. Yin, Asha Daryanani, Aian Alilin, Ross Lake, Kathy Kelly. Reproducible and effective preclinical models of prostate cancer metastasis established with PDXs [abstract]. In: Proceedings of the AACR Special Conference: Cancer Metastasis; 2022 Nov 14-17; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_2):Abstract nr B050.

Abstract B049: Breast cancer-derived angiopoietin-like 7 regulates necrotic core formation and metastasis from the tumor interior

Abstract Necrosis in the tumor interior is a common feature of aggressive cancers that is associated with poor clinical prognosis and the development of metastasis. However, how the necrotic core promotes tumor cell dissemination and metastasis remains unclear. Foundational models for cancer metastasis research include mouse, zebrafish, and chick embryo, but identifying tumor cells in transit is painstaking. Here we used a rat model of breast cancer metastasis to increase detection of dissemination events. Owing to the large size and higher blood volume of rats, we collected 10 times more circulating tumor cells (CTCs) than from mice. In the rat model, tumor dissemination was temporally correlated with the emergence of necrosis in the tumor interior. These findings were corroborated by longitudinal study of CTC abundance and tissue necrosis markers in blood plasma from patients with metastatic breast cancer. Further, we observed that dilated blood vessels were located next to necrotic regions of the tumor and that their increase was concurrent with the initiation of intratumoral necrosis and increase in CTC abundance. Bulk RNA sequencing of mouse-to-rat xenograft tumor necrotic core compared to the non-necrotic rim revealed distinct tumor-specific and host-specific transcripts in the necrotic interior. We identified angiopoietin-like 7 (Angptl7) as a tumor-specific factor localized to the peri-necrotic zone. Functional studies showed that Angptl7 loss normalizes central necrosis, peri-necrotic dilated vessels, metastasis, and reduces circulating tumor cell counts to nearly zero. Mechanistically, Angptl7 promoted vascular permeability and supported vascular remodeling in the peri-necrotic zone. Taken together, these findings show that breast tumors actively produce factors controlling central necrosis formation and metastatic dissemination from the tumor core. Tumor dissemination events are localized spatially to dilated peri-necrotic vessels in the tumor interior, and tumor dissemination is dependent functionally on the expression of a factor, Angptl7, produced by peri-necrotic tumor cells. Our findings in breast cancer models, in conjunction with recent clinical observations, provide strong evidence for tumor dissemination from the tumor interior. Citation Format: Ami Yamamoto, Yin Huang, Brad A. Krajina, Margaux McBirney, Andrea E. Doak, Carolyn L. Wang, Michael C. Haffner, Kevin J. Cheung. Breast cancer-derived angiopoietin-like 7 regulates necrotic core formation and metastasis from the tumor interior [abstract]. In: Proceedings of the AACR Special Conference: Cancer Metastasis; 2022 Nov 14-17; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_2):Abstract nr B049.

Abstract IA012: Age related changes in the tumor microenvironment drive tumor progression

Abstract The stromal compartment plays a pivotal role in tumor progression. This is best illustrated in breast cancer bone metastases, where the stromal compartment supports tumor growth, albeit through poorly defined mechanisms. p38MAPKα is frequently expressed in tumor cells and surrounding stromal cells and its expression levels correlate with poor prognosis. Using clinically relevant breast cancer metastasis models, we show that orally administered, small-molecule inhibitors of p38MAPKα or its downstream kinase, MK2, each limited outgrowth of metastatic breast cancer cells in the bone and visceral organs. Further we found that this effect is mediated by inhibition of the p38MAPKα pathway within the stromal compartment. Beyond effectively limiting metastatic tumor growth, we also found that these inhibitors reduced tumor-associated and chemotherapy-induced bone loss, which is a devastating comorbidity for cancer patients that drastically impacts their quality of life. Mechanistic studies revealed that p38MAPKα’s ability to limit tumor growth within the bone is dependent on CD4 T cells and macrophages. To determine which cell types within the bone contribute to tumor growth and bone loss, we carried out single cell RNA-sequencing of stromal cells located within the bone metastatic lesion and cells outside the lesion. We found numerous differences that could explain how the stromal compartment contributes to tumor progression and bone loss and how inhibition of p38MAPKα or MK2 contribute. These data underscore the vital role stromal-derived factors play in tumor progression and identify the p38MAPK-MK2 pathway as a promising therapeutic target for metastatic disease and prevention of tumor-induced bone loss. Citation Format: Sheila A. Stewart. Age related changes in the tumor microenvironment drive tumor progression [abstract]. In: Proceedings of the AACR Special Conference: Aging and Cancer; 2022 Nov 17-20; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2022;83(2 Suppl_1):Abstract nr IA012.

Alternatively Spliced Isoforms of MUC4 and ADAM12 as Biomarkers for Colorectal Cancer Metastasis.

There is a pertinent need to develop prognostic biomarkers for practicing predictive, preventive and personalized medicine (PPPM) in colorectal cancer metastasis. The analysis of isoform expression data governed by alternative splicing provides a high-resolution picture of mRNAs in a defined condition. This information would not be available by studying gene expression changes alone. Hence, we utilized our prior data from an exon microarray and found ADAM12 and MUC4 to be strong biomarker candidates based on their alternative splicing scores and pattern. In this study, we characterized their isoform expression in a cell line model of metastatic colorectal cancer (SW480 & SW620). These two genes were found to be good prognostic indicators in two cohorts from The Cancer Genome Atlas database. We studied their exon structure using sequence information in the NCBI and ENSEMBL genome databases to amplify and validate six isoforms each for the ADAM12 and MUC4 genes. The differential expression of these isoforms was observed between normal, primary and metastatic colorectal cancer cell lines. RNA-Seq analysis further proved the differential expression of the gene isoforms. The isoforms of MUC4 and ADAM12 were found to change expression levels in response to 5-Fluorouracil (5-FU) treatment in a dose-, time- and cell line-dependent manner. Furthermore, we successfully detected the protein isoforms of ADAM12 and MUC4 in cell lysates, reflecting the differential expression at the protein level. The change in the mRNA and protein expression of MUC4 and ADAM12 in primary and metastatic cells and in response to 5-FU qualifies them to be studied as potential biomarkers. This comprehensive study underscores the importance of studying alternatively spliced isoforms and their potential use as prognostic and/or predictive biomarkers in the PPPM approach towards cancer.

Synthetic Lethal Interaction with BCL-XL Blockade Deepens Response to Cetuximab in Patient-Derived Models of Metastatic Colorectal Cancer.

Approximately 20% of patients with RAS wild-type metastatic colorectal cancer (mCRC) experience objective responses to the anti-EGFR antibody cetuximab, but disease eradication is seldom achieved. The extent of tumor shrinkage correlates with long-term outcome. We aimed to find rational combinations that potentiate cetuximab efficacy by disrupting adaptive dependencies on antiapoptotic molecules (BCL2, BCL-XL, MCL1). Experiments were conducted in patient-derived xenografts (PDX) and organoids (PDXO). Apoptotic priming was analyzed by BH3 profiling. Proapoptotic and antiapoptotic protein complexes were evaluated by co-immunoprecipitation and electroluminescence sandwich assays. The effect of combination therapies was assessed by caspase activation in PDXOs and by monitoring PDX growth. A population trial in 314 PDX cohorts, established from as many patients, identified 46 models (14.6%) with appreciable (>50% tumor shrinkage) but incomplete response to cetuximab. From these models, 14 PDXOs were derived. Cetuximab primed cells for apoptosis, but only concomitant blockade of BCL-XL precipitated cell death. Mechanistically, exposure to cetuximab induced upregulation of the proapoptotic protein BIM and its sequestration by BCL-XL. Inhibition of BCL-XL resulted in displacement of BIM, which was not buffered by MCL1 and thereby became competent to induce apoptosis. In five PDX models, combination of cetuximab and a selective BCL-XL inhibitor triggered apoptosis and led to more pronounced tumor regressions and longer time to relapse after treatment discontinuation than cetuximab alone. In mCRC tumors that respond to cetuximab, antibody treatment confers a synthetic-lethal dependency on BCL-XL. Targeting this dependency unleashes apoptosis and increases the depth of response to cetuximab.

The Chemotherapeutic Efficacy of Hyaluronic Acid Coated Polymeric Nanoparticles against Breast Cancer Metastasis in Female NCr-Nu/Nu Nude Mice.

Polyethylene glycol (PEG) coated Poly lactic-co-glycolic acid (PLGA) nanoparticles (NPs) for cancer treatment are biocompatible, nonimmunogenic and accumulate in tumour sites due to the enhanced permeability and retention (EPR). Doxorubicin (DOX) is a potent but cardiotoxic anticancer agent. Hyaluronic acid (HA) occurs naturally in the extra-cellar matrix and binds to CD44 receptors which are overexpressed in cancer metastasis, proven to be characteristic of cancer stem cells and responsible for multidrug resistance. In this study, an athymic mice model of breast cancer metastasis was developed using red fluorescent protein (RFP)-labelled triple negative cancer cells. The animals were divided into four treatment groups (Control, HA-PEG-PLGA nanoparticles, PEG-PLGA nanoparticles, and Free DOX). The tumour size growth was assessed until day 25 when animals were sacrificed. Mice treated with HA-PEG-PLGA NPs inhibited tumour growth. The tumour growth at day 25 (118% ± 13.0) was significantly (p &lt; 0.05) less than PEG-PLGA NPs (376% ± 590 and control (826% ± 970). Fluorescent microscopy revealed that HA-PEG-PLGA NPs had significantly (p &lt; 0.05) less metastasis in liver, spleen, colon, and lungs as compared to control and to Free DOX groups. The efficacy of HA-PEG-PLGA NPs was proven in vivo. Further pharmacokinetic and toxicity studies are required for this formulation to be ready for clinical research.

Bifunctional cancer cell-based vaccine concomitantly drives direct tumor killing and antitumor immunity.

The administration of inactivated tumor cells is known to induce a potent antitumor immune response; however, the efficacy of such an approach is limited by its inability to kill tumor cells before inducing the immune responses. Unlike inactivated tumor cells, living tumor cells have the ability to track and target tumors. Here, we developed a bifunctional whole cancer cell-based therapeutic with direct tumor killing and immunostimulatory roles. We repurposed the tumor cells from interferon-β (IFN-β) sensitive to resistant using CRISPR-Cas9 by knocking out the IFN-β-specific receptor and subsequently engineered them to release immunomodulatory agents IFN-β and granulocyte-macrophage colony-stimulating factor. These engineered therapeutic tumor cells (ThTCs) eliminated established glioblastoma tumors in mice by inducing caspase-mediated cancer cell apoptosis, down-regulating cancer-associated fibroblast-expressed platelet-derived growth factor receptor β, and activating antitumor immune cell trafficking and antigen-specific T cell activation signaling. This mechanism-based efficacy of ThTCs translated into a survival benefit and long-term immunity in primary, recurrent, and metastatic cancer models in immunocompetent and humanized mice. The incorporation of a double kill-switch comprising herpes simplex virus-1 thymidine kinase and rapamycin-activated caspase 9 in ThTCs ensured the safety of our approach. Arming naturally neoantigen-rich tumor cells with bifunctional therapeutics represents a promising cell-based immunotherapy for solid tumors and establishes a road map toward clinical translation.

Animal models of bone metastatic prostate cancer.

Metastatic disease is a main cause of mortality in prostate cancer and remains to be incurable despite emerging new treatment agents. Development of novel treatment agents are confined within the boundaries of our knowledge of bone metastatic prostate cancer. Exploration into the underlying mechanism of metastatic tumorigenesis and treatment resistance will further expose novel targets for novel treatment agents. Up to date, many of these researches have been conducted with animal models which have served as classical tools that play a pivotal role in understanding the fundamental nature of cancer. The ability to reproduce the natural course of prostate cancer would be of profound value. However, currently available models do not reproduce the entire process of tumorigenesis to bone metastasis and are limited to reproducing small portions of the entire process. Therefore, knowledge of available models and understanding the strengths and weaknesses for each model is key to achieve research objectives. In this article, we take an overview of cell line injection animal models and patient derived xenograft models that have been applied to the research of human prostate cancer bone metastasis.

The ADAM9/WISP-1 axis cooperates with osteoblasts to stimulate primary prostate tumor growth and metastasis.

Background: Metastatic prostate cancer (PCa) predicts a poor prognosis and lower likelihood of survival. Osteoblasts (OBs) are known to be responsible for the synthesis and mineralization of bone, although it is unclear as to whether PCa in the prostate gland cooperates with OBs in bone to promote PCa malignant transformation. We aimed to elucidate how primary PCa cells cooperate with distal OBs and contribute to the vicious cycle that leads to metastatic PCa. Methods: N-cadherin, E-cadherin, and Twist protein expression were measured by Western blot. Twist translocation into the nucleus was detected by the immunofluorescence (IF) assay. Enzyme-linked immunosorbent assay (ELISA) detected protein levels in human serum samples. Levels of candidate protein expression were examined by the human cytokine array. Prostate tumor growth and metastasis were analyzed by orthotopic and metastatic prostate cancer models, respectively. Immunohistochemistry (IHC) staining was used to observe ADAM metallopeptidase domain 9 (ADAM9) and WNT1 inducible signaling pathway protein 1 (WISP-1) expression in tissue. Results: Our in vitro and in vivo analyses have now discovered that primary PCa expressing ADAM9 protein enables the transformation of OBs into PCa-associated osteoblasts (PCa-OBs), inducing WISP-1 secretion from PCa-OBs in the bone microenvironment. The upregulation of WISP-1 in bone provided feedback to primary PCa and promoted PCa cell aggressiveness via epithelial-mesenchymal transition (EMT) activity. Elevated levels of WISP-1 expression were detected in the serum of patients with PCa. ADAM9 levels were overexpressed in tumor tissue from PCa patients; ADAM9 blockade interrupted OB-induced release of WISP-1 and also suppressed primary tumor growth and distal metastasis in orthotopic PCa mouse models. Conclusion: Our study suggests that the ADAM9/WISP-1 axis assists with metastatic PCa progression. Thus, targeting the ADAM9/WISP-1 axis may help to prevent the malignant phenotypes of PCa cells.

Unfavorable tumor responses to immunotherapy in the liver: Lessons learned from clinical and preclinical studies

Objective: Immunotherapy with immune checkpoint inhibitors (ICIs) has become a standard of care for many malignancies. The tumor microenvironment (TME) varies across different organs and affects tumor initiation, progression, and treatment outcomes. Organ-specific differential responses to ICIs have been observed in various cancers. The underlying mechanisms warrant further investigation. Data Sources and Study Selection: We enrolled relevant clinical and preclinical studies conducted by our groups and others. Current evidence and data were reviewed and future implication was discussed. Results: In patients with advanced hepatocellular carcinoma or esophageal cancer, non-small cell lung cancer, or melanoma with liver metastases, the efficacy of ICI-based therapy was generally lower in the liver than in other organs. The mouse liver cancer study showed that myeloid-derived suppressor cells (MDSCs) might play a role in immunosuppressive TME in the liver as compared to subcutaneous tissues; targeting MDSCs enhanced anti-tumor efficacy in the liver. The metastatic colon cancer models showed that monotherapy with anti-programmed death ligand-1 (PD-L1) antibody was less effective in suppressing tumor growth in the liver than in subcutaneous tissues. Mechanistically, modulation of hepatic innate immune cells was associated with the improved response of anti-PD-L1 antibody in the liver. Conclusion: The relatively unfavorable tumor response to immunotherapy in the liver of various cancers may be attributable to the immunosuppressive hepatic TME. Future comprehensive immune profiling is required to identify key factors and mechanisms in specific organs to overcome immunosuppressive TME, particularly in the liver.

Engineering magnetotactic bacteria MVs to synergize chemotherapy, ferroptosis and immunotherapy for augmented antitumor therapy.

One main obstacle to targeted cancer therapies is the immunosuppressive tumor microenvironment, which can facilitate tumor growth and induce resistance to antitumor treatments. Recent studies have indicated that treatment combined with immunotherapy often yields a better prognosis than monotherapy. Bacterial membrane vesicles (MVs), nanostructures released from the membrane of bacteria, can be used as natural nanocarriers for drug delivery and stimulate an immune response because of their immunogenicity. Inspired by the development of synergistic therapeutic strategies, we herein propose a novel nanovaccine-based platform to achieve chemotherapy, ferroptosis therapy, and immunotherapy simultaneously. By simply culturing magnetotactic bacteria in the medium with doxorubicin (DOX) and then extracting specialized MVs (BMVs), BMV@DOX, which are membrane vesicles containing iron ions and DOX, were obtained. We confirmed that in BMV@DOX, the BMV component can stimulate the innate immune system, DOX acts as the chemotherapeutic agent and iron ions will induce ferroptosis. Furthermore, BMV@DOX vesicles modified with DSPE-PEG-cRGD peptides (T-BMV@DOX) have minimized systemic toxicity and increased tumor-specificity. We demonstrated that the smart MVs-based nanovaccine system not only showed superior performance in the treatment of 4T1 breast cancer but also effectively restrained the growth of drug-resistant MCF-7/ADR tumors in mice. Moreover, the nanovaccine could abrogate in vivo lung metastasis of tumor cells in a 4T1-Luc cell induced-lung breast cancer metastasis model. Collectively, the MVs-based nanoplatform offers an alternative promise for surmounting the limitations of monotherapy and may deserve further study for application in synergistic cancer therapy.

Abstract IA015: Combined single cell atlasing and organoid modeling reveal progressive plasticity during human colorectal cancer metastasis

Abstract Metastatic cancers invariably relapse due to the emergence of therapy resistant subclones that are capable of self-renewal, slow cell-cycling, tumor re-initiation and therapy resistance. However, the molecular mechanisms that underpin the phenotypic plasticity of metastasis stem cells, their relationship to tumor initiating cancer stem cells and macrometastasis, and the co-evolution of the immune response to dynamically emerging tumor regenerative states are not understood. We are adopting a patient-derived functional biospecimen approach combining (1) hypothesis-generation using transcriptomics, epigenomics and spatial/histological analysis of patient samples of primary and metastatic gastrointestinal (GI) cancer with (2) mechanistic dissection in cutting-edge patient-derived organoid models, including co-cultures with immune/stromal cells, and (3) genetically engineered and orthotopic transplantation models of metastatic GI cancer. By profiling, lineage tracing and genetically interrogating the evolving transcriptomic and chromatin landscapes of regenerative metastatic states, we are defining the molecular mechanisms that underpin the phenotypic plasticity of metastatic cancer, and the co-evolution of the tumor microenvironmental response to dynamically emerging tumor regenerative states. Our approach is unveiling crucial signaling nodes required for metastatic plasticity that can be therapeutically targeted to improve outcomes for patients with advanced cancer. Citation Format: Karuna Ganesh. Combined single cell atlasing and organoid modeling reveal progressive plasticity during human colorectal cancer metastasis [abstract]. In: Proceedings of the AACR Special Conference on Colorectal Cancer; 2022 Oct 1-4; Portland, OR. Philadelphia (PA): AACR; Cancer Res 2022;82(23 Suppl_1):Abstract nr IA015.