Treatment Of Advanced Metastatic Disease Research Articles

Abstract 5742: Pharmacologic modulation of RNA splicing enhances anti-tumor immunity

Abstract Immune checkpoint blockade therapy has revolutionized cancer care, including the treatment of advanced metastatic disease. However, most patients derive little or no clinical benefit from these therapies and many cancer types are notoriously non-responsive. Motivated by (1) the correlation between tumor neoantigen abundance and anti-tumor immunity and (2) that most cancers are characterized by widespread dysregulation of RNA processing, we reasoned that pharmacologic modulation of RNA splicing might increase cancer cell immunogenicity via the generation of splicing-derived neoantigens. We demonstrated that two compounds which modulate RNA splicing via distinct mechanisms, inhibited tumor growth and enhanced response to immune checkpoint blockade in a manner dependent on host T cells and peptides presented on tumor MHC class I. Critical for their clinical translatability, therapeutic doses of splicing inhibitors were non-toxic, tolerated by the host immune system, and did not affect T cell activation, proliferation, and anti-cancer killing activities. Mechanistically, splicing modulation induced stereotyped, dose-dependent “splicing failure” — dramatic intron retention, alternative exon skipping, etc. — that was consistent across multiple mouse and human tumor types. By combining RNA-seq-based peptide predictions and mass spectrometry of the MHC I-bound immunopeptidome, we identified drug-induced, splicing-derived peptides that promote the expansion of antigen-specific CD8+ T cells and trigger anti-tumor T cell responses in vivo. These data definitively identify splicing modulation as an untapped source of immunogenic peptides and provide a means to enhance response to checkpoint blockade that is readily translatable to the clinic. Citation Format: James D. Thomas, Sydney X. Lu, Emma De Neef, Erich Sabio, Benoit Rousseau, Mathieu Gigoux, David A. Knorr, Benjamin Greenbaum, Yuval Elhanati, Simon J. Hogg, Andrew Chow, Arnab Ghosh, Abigail Xie, Dmitriy Zamarin, Daniel Cui, Caroline Erickson, Michael Singer, Hana Cho, Eric Wang, Bin Lu, Benjamin H. Durham, Harshal Shah, Diego Chowell, Austin M. Gabel, Yudao Shen, Jing Liu, Jian Jin, Matthew C. Rhodes, Richard E. Taylor, Henrik Molina, Jedd D. Wolchok, Taha Merghoub, Luis A. Diaz Jr, Omar Abdel-Wahab, Robert K. Bradley. Pharmacologic modulation of RNA splicing enhances anti-tumor immunity. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5742.

Neoadjuvant photodynamic therapy augments immediate and prolonged oxaliplatin efficacy in metastatic pancreatic cancer organoids.

Effective treatment of advanced metastatic disease remains the primary challenge in the management of inoperable pancreatic cancer. Current therapies such as oxaliplatin (OxPt)-based chemotherapy regimens (FOLFIRINOX) provide modest short-term survival improvements, yet with significant toxicity. Photodynamic therapy (PDT), a light-activated cancer therapy, demonstrated clinical promise for pancreatic cancer treatment and enhances conventional chemotherapies with non-overlapping toxicities. This study investigates the capacity of neoadjuvant PDT using a clinically-approved photosensitizer, benzoporphyrin derivative (BPD, verteporfin), to enhance OxPt efficacy in metastatic pancreatic cancer. Treatment effects were evaluated in organotypic three-dimensional (3D) cultures, clinically representative models that bridge the gap between conventional cell cultures and in vivo models. The temporally-spaced, multiparametric analyses demonstrated a superior efficacy for combined PDT+OxPt compared to each monotherapy alone, which was recapitulated on different organotypic pancreatic cancer cultures. The therapeutic benefit of neoadjuvant PDT to OxPt chemotherapy materialized in a time-dependent manner, reducing residual viable tissue and tumor viability in a manner not achievable with OxPt or PDT alone. These findings emphasize the need for intelligent combination therapies and relevant models to evaluate the temporal kinetics of interactions between mechanistically-distinct treatments and highlight the promise of PDT as a neoadjuvant treatment for disseminated pancreatic cancer.

The potential clinical promise of ‘multimodality’ metronomic chemotherapy revealed by preclinical studies of metastatic disease

We present a rationale for further clinical development and assessment of metronomic chemotherapy on the basis of unexpected results obtained in translational mouse models of cancer involving treatment of advanced metastatic disease. Historically, mouse cancer therapy models have been dominated by treating established primary tumors or early stage low volume microscopic disease. Treatment of primary tumors is also almost always the case when using genetically engineered mouse models (GEMMs) of cancer or patient-derived xenografts (PDXs). Studies using such models, and others including transplanted cell lines, often yield highly encouraging results which are seldom recapitulated in the clinic, especially when assessed in randomized phase III clinical trials. While there are likely many different reasons for this discrepancy, one is likely the failure to recapitulate treatment of advanced visceral metastatic disease in mice. With this gap in mind, we have developed a number of models of metastatic human tumor xenografts (and more recently, of mouse tumors in syngeneic immunocompetent mice). A pattern of response we have observed with various targeted agents, e.g. VEGF pathway targeting antiangiogenic drugs or trastuzumab, is effective when treating primary tumors in contrast to a complete or severely reduced lack of such efficacy when treating advanced metastatic disease. Interestingly, an exception to this pattern has been observed using various continuous low-dose metronomic chemotherapy regimens, where counterintuitively, superior responses are observed in the metastatic setting, as well as superiority or equivalence of metronomic chemotherapy over standard maximum tolerated dose (MTD) chemotherapy, with lesser toxicity. The basis for these encouraging results may be related to the multiple mechanisms responsible for the anti-tumor effects and longer duration of metronomic chemotherapy regimens made possible by lesser toxicity. These include antiangiogenesis, stimulation of the immune system, stromal cell targeting in tumors, and possibly direct tumor cell targeting, including targeting cancer stem cells (CSCs). In addition, metronomic chemotherapy regimens minimize or even eliminate the problem of chemotherapy-induced host responses that may actually secondarily promote tumor growth and malignancy after causing an initial and beneficial anti-tumor response. We suggest that future preclinical studies of metronomic chemotherapy should be concentrated in the following areas: i) further comparative assessment of anti-tumor efficacy in primary vs metastatic treatment settings; ii) rigorous comparative assessment of conventional MTD chemotherapy vs metronomic chemotherapy using the same agent; iii) assessment of potential predictive biomarkers for metronomic chemotherapy, and methods to determine optimal biologic dose and schedule; and iv) a further detailed assessment of the potential of different chemotherapy drugs administered using MTD or metronomic regimens on stimulating or suppressing components of the innate or adaptive immune systems.

Planned Treatment of Advanced Metastatic Disease with Completion Ablation After Hepatic Resection

PurposeThe aim of this study is to describe a modified treatment strategy with image-guided percutaneous ablation after hepatic resection as a completion method to surgical eradication of liver metastases (“completion ablation [CA]”). MethodsWe conducted a retrospective analyses of patients who underwent CA within 180 days from the liver surgical resection to eradicate liver metastases present on the pre-surgical cross-sectional imaging or identified during intraoperative ultrasound that were not resected due to various reasons. Lesions treated with CA were evaluated for local tumor progression (LTP). Patients were evaluated for hepatic- and overall-recurrence-free survivals (hepatic-RFS and overall-RFS, respectively) and overall survival (OS). ResultsSixteen patients (10 females; median age 55 years, range 28–69) underwent CA of 21 lesions (median size 8 mm, range 6 to 22). Indications for the use of CA were small future liver remnant in 10 (63%), inability to identify the lesion during surgical exploration in 3 (19%), and technical difficulty of resection in 3 (19%) patients. No liver-related complications were recorded following the surgical resection or the CA procedures. Primary and secondary CA efficacy rates were 95 and 100%, respectively. LTP was 0% at a median clinical follow-up of 27 months (range 4.0–108 months). Five-year hepatic-RFS, overall-RFS, and OS were 36, 16, and 51%, respectively. ConclusionThe use of CA as a complement to surgical resection is safe and effective. Such approach could potentially expand the surgical candidacy for patients with limited liver functional reserve and reduce postoperative morbidity and mortality in this selected patient population with more advanced disease.

Development of Patient Derived Xenograft Models of Overt Spontaneous Breast Cancer Metastasis: A Cautionary Note.

Several approaches are being evaluated to improve the historically limited value of studying transplanted primary tumors derived by injection of cells from established cell lines for predicting subsequent cancer therapy outcomes in patients and clinical trials. These approaches include use of genetically engineered mouse models (GEMMs) of spontaneous tumors, or patient tumor tissue derived xenografts (PDXs). Almost all such therapy studies utilizing such models involve treatment of established primary tumors. An alternative approach we have developed involves transplanted human tumor xenografts derived from established cell lines to treat mice with overt visceral metastases after primary tumor resection. The rationale is to mimic the more challenging circumstance of treating patients with late stage metastatic disease. These metastatic models entail prior in vivo selection of heritable, phenotypically stable variants with increased aggressiveness for spontaneous metastasis; they were derived by orthotopic injection of tumor cells followed by primary tumor resection and serial selection of distant spontaneous metastases, from which variant cell lines having a more aggressive heritable metastatic phenotype were established. We attempted to adopt this strategy for breast cancer PDXs. We studied five breast cancer PDXs, with the emphasis on two, called HCI-001 and HCI-002, both derived from triple negative breast cancer patients. However significant technical obstacles were encountered. These include the inherent slow growth rates of PDXs, the rarity of overt spontaneous metastases (detected in only 3 of 144 mice), very high rates of tumor regrowths at the primary tumor resection site, the failure of the few human PDX metastases isolated to manifest a more aggressive metastatic phenotype upon re-transplantation into new hosts, and the formation of metastases which were derived from de novo mouse thymomas arising in aged SCID mice that we used for the experiments. We discuss several possible strategies that may be employed to overcome these limitations. Uncovering the basis of the failure to detect a high rate of overt spontaneous distant metastases having a heritable phenotype in PDX models may reveal new insights into the biology and treatment of advanced metastatic disease.

Abstract 3020: Patient-derived xenograft (PDX) models to study the role of breast cancer stem cells in metastasis formation

Abstract Although advances have been made in the treatment of localized breast cancer, there has been less progress in the treatment of advanced metastatic disease. This disease is an oncoming therapeutic challenge for breast cancer since it is always fatal. Conventional therapies may fail to target cancer stem cells (CSC). Metastatic breast cancer may thus benefit from current intensive research in the CSC field. Several studies suggest that CSCs are the only cancer cells responsible for metastasis formation. CSCs may have the ability to disseminate in blood circulation as circulating tumor cells (CTCs) and to colonize new sites. To better understand the biological processes that link CSCs and metastasis, we have generated a xenobank of 50 patient-derived xenografts (PDXs) of primary tumors grafted in the humanized mammary fat pad of immunodeficient mice. These models reflect the heterogeneity of primary tumors both at molecular and cellular level. Using a lentiviral vector, we infected our PDXs to obtain GFP-luciferase-positive models designed to monitor metastasis development from the orthotopic site. To mimick the patient therapeutic management, metastasis formation is monitored during tumor growth but also after tumor surgical removal. Metastases are collected and analyzed for histology and phenotype. The different metastatic patterns are correlated with the mutational profile of PDX. CTCs are also monitored at different time of the metastatic process using a specific filter (ISET) for cell characterization and phenotype. PDXs can be classified in tumor groups with similar metastatic tropisms. To depict the role of CSC from primary tumors in the tropism of their metastases, we collected and genomic profiled the ALDEFLUOR-positive CSCs in orthotopic tumors from different models with distinct metastatic pattern. These different PDX models lead to a better understanding of the role of breast CSCs in metastasis formation from CTCs to well-constituted metastasis and their study may identify targets able to design future therapeutic strategies. Citation Format: Christophe Ginestier, Danae Lartigue, Olivier Cabaud, Aurelie Malzac, Julien Wicinski, Emmanuelle Josselin, Pascal Finetti, Jose Adelaide, Francois Bertucci, Max Chaffanet, Daniel Birnbaum, Emmanuelle Charafe-Jauffret. Patient-derived xenograft (PDX) models to study the role of breast cancer stem cells in metastasis formation. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 3020. doi:10.1158/1538-7445.AM2014-3020

Abstract 1452: Examination of mechanisms involved in spontaneous melanoma metastasis to CNS

Abstract Cerebral metastases occur in a majority of metastatic melanoma patients and are the major cause of mortality in those cases. Testing of novel therapeutic approaches has been slowed by the absence of appropriate preclinical models of spontaneous metastatic melanoma, particularly spontaneous CNS metastasis. To examine the efficacy of potentially promising treatment regimens, a highly visceral metastatic variant of the human melanoma WM239 cell line, named 6-4L, was developed and used to test the effectiveness of metronomic chemotherapy in the treatment of advanced metastatic disease. Concurrent low-dose cyclophosphomide/vinblastine led to significant disease control of mice with overt metastases in lungs, liver and lymph nodes. Among mice that survived the long-term treatment, 20% showed the presence of spontaneous brain metastases which likely emerged as a result of prolonged survival mediated by the therapy. From these, 2 cell lines (131/4-5B1 and 131/4-5B2) were generated which metastasize spontaneously to brain parenchyma. This constitutes the first model of heritable spontaneous melanoma brain metastasis by a human cell line from a subdermal transplant, without any therapeutic intervention. Characterization shows two salient functional alterations that may contribute to this phenotype 1) adhesion to brain-endothelial cells and 2) proliferation in the presence of brain-derived factors. When compared to poorly or highly metastatic cell lines (WM239A and 113/6-4L respectively), microarray analysis shows that 4-5B1/B2 cell lines have markedly different expression profiles. These cell lines show differential expression of 108 genes, thirteen of which share a common alteration for both brain-metastatic cell lines, including ednrb (endothelin receptor B) and bcl2a1 (BCL2-related protein A1), which stand out as potentially relevant. These molecules have been previously associated with increased proliferation in the presence of ENT-3; a peptide expressed in the brain, as well as resistance to TNF induced apoptosis and increased metastatic potential. Lentiviral vectors were used to induce stable upregulation of these genes in the otherwise non-brain metastatic parental 113/6-4L cell line. This upregulation mediated an increase in metastatic potential and, in the case of EDNRB, increased intracranial tumor growth. Future efforts will focus on characterizing the alterations in these cell lines, to confirm their clinical relevance and to test novel inhibitors for treating melanoma brain metastases. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 1452.

Abstract C49: Combination treatment with metronomic cyclophosphamide and the EGFR monoclonal antibody nimotuzumab is efficacious and non-toxic in a preclinical model of advanced triple negative breast cancer

Abstract Low dose, metronomic chemotherapy with cyclophosphamide has shown activity in the treatment of advanced breast cancer, and has been paired with targeted agents such as trastuzumab and bevacizumab for long term therapy, with encouraging results. The epidermal growth factor receptor (EGFR) pathway may be a relevant target for the treatment of triple-negative breast cancer, a tumor type with an aggressive behavior and limited therapeutic options. Nimotuzumab is a humanized monoclonal antibody targeting EGFR with an affinity that is lower than currently approved agents, such as cetuximab and panitumumab. This leads to preferential targeting of EGFR-overexpressing tumors, minimizing toxicity, making it well suited for long term dosing, including possible combination therapy with minimally toxic chemotherapeutic regimens, when treating tumors with high EGFR expression. The objective of this study was to evaluate nimotuzumab in combination with metronomic cyclophosphamide in a preclinical model of advanced, triple negative breast cancer. Increasingly aggressive metastatic variants of the MDA-MB-231 human breast cancer cell line were selected through passage in vivo, resulting in a line termed 164/8-1B, characterized as highly metastatic to many organs, including lymph nodes, lung, and brain. This variant also had increased EGFR expression compared to the parental cell line. Combination therapy with nimotuzimab twice weekly and continous low-dose cyclophosphamide resulted in significant primary tumor growth delay in the metastatic variant, compared to the parental cell line. In addition, the combination resulted in a significant survival advantage over cyclophosphamide alone in the advanced metastatic model. Nimotuzumab displayed single agent activity in primary tumor xenografts but not in the treatment of advanced metastatic disease. Primary tumor regrowth in the mammary fat pad occurred with similar frequency across treatment groups, however the resulting tumor size was decreased in mice receiving combination treatment. Lymph node metastasis was observed in 40–60% of mice in each treatment group, with the exception of those that received combination therapy, where no gross evidence of lymphadenomegaly was observed. Finally, cell lines established from lung metastases from 3 mice receiving combination therapy showed EGFR expression, suggesting that resistance to treatment was not associated with loss of target expression. In conclusion, combination therapy with low dose, continuous cyclophosphamide and the EGFR monoclonal antibody nimotuzumab was an efficacious regimen in this advanced, metastatic, triple negative, EGFR overexpressing breast cancer model, and would be expected to be minimally toxic to patients. This combination approach should be considered for this patient population in future clinical trials. Citation Information: Mol Cancer Ther 2009;8(12 Suppl):C49.

Brain magnetic resonance imaging changes after sorafenib and sunitinib chemotherapy in patients with advanced renal cell and breast carcinoma

The authors report novel imaging findings associated with the treatment of sorafenib (Nexavar) and sunitinib (Sutant), 2 agents used in the treatment of advanced metastatic disease. Patients with renal cell and breast carcinoma metastases to the brain were identified from the prospective database at the Penn State Hershey Medical Center and Penn State Cancer Institute. Four patients who received sorafenib or sunitinib after surgical or radiosurgical treatment of their metastases were identified from the database. Clinical and/or radiographic changes consisting of seizures and cognitive or motor changes were described, associated with an increase in peritumoral edema and enhancement. These findings were observed to improve with discontinuation of the medications. The administration of sorafenib and sunitinib in patients with metastatic breast and renal cell carcinoma may lead to reversible clinical and imaging changes following surgical or radiosurgical treatment of their brain lesions. The authors hypothesize that leakage of the drug across a locally impaired blood-brain barrier contributes to peritumoral edema and inflammation, which may be erroneously interpreted as disease progression.

The contributions of cyclooxygenase-2 to tumor angiogenesis.

Cyclooxygenase-2 (COX-2) is an immediate early response gene that can be induced by a variety of tumor promoters, cytokines, growth factors and hypoxia. COX-2 overexpression is linked to all stages of carcinogenesis with the enzyme localized to the neoplastic cells, microvascular endothelial cells, and stromal fibroblasts. The contributions of COX-2 in tumor angiogenesis include: (a) the increased expression of the proangiogenic growth factor VEGF; (b) the production of the eicosanoid products thromboxane A2, PGE2 and PGI2 that can directly stimulate endothelial cell migration and growth factor-induced angiogenesis; and potentially, (c) the inhibition of endothelial cell apoptosis by stimulation of Bcl-2 or Akt activation. Selective pharmacological inhibitors of COX-2 as angiosuppressive agents could have therapeutic benefit in the treatment of neoplastic disease from prevention through treatment of advanced metastatic disease. These agents are safe and well tolerated and can be added to chemotherapy and radiation therapy where angiogenesis inhibitors appear to provide at least additive therapeutic benefit.