EPI-X4, a CXCR4 antagonist inhibits tumor growth in pancreatic cancer and lymphoma models

Endogenous peptide inhibitor for CXCR4 (EPI-X4) is a CXCR4 antagonist with potential for cancer therapy. It is a processed fragment of serum albumin from the hemofiltrate of dialysis patients. This study reports the efficacy of fifteen EPI-X4 derivatives in pancreatic cancer and lymphoma models. In vitro, the peptides were investigated for antiproliferation (cytotoxicity) by MTT assay. The mRNA expression for CXCR4 and CXCL12 was determined by RT-PCR, chip array and RNA sequencing. Chip array analysis yielded 634 genes associated with CXCR4/CXCL12 signaling. About 21% of these genes correlated with metastasis in the context of cell motility, proliferation, and survival. Expression levels of these genes were altered in pancreatic cancer (36%), lymphoma models (53%) and in patients' data (58%). EPI-X4 derivatives failed to inhibit cell proliferation due to low expression of CXCR4 in vitro, but inhibited tumor growth in the bioassays with significant efficacy. In the pancreatic cancer model, EPI-X4a, f and k inhibited mean tumor growth by > 50% and even caused complete remissions. In the lymphoma model, EPI-X4b, n and p inhibited mean tumor growth by > 70% and caused stable disease. Given the non-toxic and non-immunogenic properties of EPI-X4, these findings underscore its status as a promising therapy of pancreatic cancer and lymphoma and warrant further studies. SIMPLE SUMMARY: This study examined the value of chemokine receptor CXCR4 as an antineoplastic target for the endogenous peptide inhibitor of CXCR4 (EPI-X4), a 12-meric peptide derived from serum albumin. EPI-X4 inhibits CXCR4 interaction with its natural ligand, CXCL12 (SDF1). Therefore, malignancies (including pancreatic cancer and lymphoma) that depend on the CXCR4/CXCL12 pathway for progression can be targeted with EPI-X4. Of 634 genes that were linked to the CXCR4/CXCL12 pathway, 21% were associated with metastasis. In cultured human Suit2-007 pancreatic cancer cells, CXCR4 showed low to undetectable expression, which was why EPI-X4 did not inhibit pancreatic cancer cell proliferation. These findings were different in vivo, where CXCR4 was highly expressed and EPI-X4 inhibited tumor growth in rodents harboring pancreatic cancer or lymphoma. In the pancreatic cancer model, EPI-X4 derivatives a, f and k caused complete remissions, while in lymphomas EPI-X4 derivatives b, n and p caused stable disease.

Establishment and Thorough Characterization of Xenograft (PDX) Models Derived from Patients with Pancreatic Cancer for Molecular Analyses and Chemosensitivity Testing

Patient-derived xenograft (PDX) tumor models are essential for identifying new biomarkers, signaling pathways and novel targets, to better define key factors of therapy response and resistance mechanisms. Therefore, this study aimed at establishing pancreas carcinoma (PC) PDX models with thorough molecular characterization, and the identification of signatures defining responsiveness toward drug treatment. In total, 45 PC-PDXs were generated from 120 patient tumor specimens and the identity of PDX and corresponding patient tumors was validated. The majority of engrafted PDX models represent ductal adenocarcinomas (PDAC). The PDX growth characteristics were assessed, with great variations in doubling times (4 to 32 days). The mutational analyses revealed an individual mutational profile of the PDXs, predominantly showing alterations in the genes encoding KRAS, TP53, FAT1, KMT2D, MUC4, RNF213, ATR, MUC16, GNAS, RANBP2 and CDKN2A. Sensitivity of PDX toward standard of care (SoC) drugs gemcitabine, 5-fluorouracil, oxaliplatin and abraxane, and combinations thereof, revealed PDX models with sensitivity and resistance toward these treatments. We performed correlation analyses of drug sensitivity of these PDX models and their molecular profile to identify signatures for response and resistance. This study strongly supports the importance and value of PDX models for improvement in therapies of PC.

Abstract 44: An in vivo platform of pre-characterized renal cell carcinoma (RCC) patient-derived xenograft models allows the preclinical evaluation of patient-tailored intervention strategies

Renal cell carcinoma (RCC), is the most common kidney cancer of adults, originating in the lining of the proximal convoluted tubule. Prognosis is poor in patients with advanced or metastasized RCC. Drug resistance towards Standard of Care (SoC, incl. everolimus, sorafenib, or sunitinib) drugs develops frequently within months. Therefore, development of novel options to target acquired TKI resistance mechanisms in advanced and metastatic RCC is still an urgent medical need. Preclinical models with high translational relevance can promote the implementation of novel personalized therapies. To evaluate novel targeted therapies and their combinations in preclinical settings, patient-derived xenograft (PDX) models represent valuable tools. Responsible local ethics committees approved usage of patient tissue and all animal procedures. In this study, RCC tissue from 167 patients was collected and xenotransplanted in mice. Partially, a multi-region approach, xenografting tissue from different regions of one tumor, was used. PDX models were characterized by immunohistochemistry (Ki-67, CD31, Pax2 and Pax8 antibodies), gene expression, copy number variations and mutational analyses. To evaluate in vivo drug response of RCC PDX models, mice transplanted with PDX tumors were treated with bevacizumab (i.p.), with everolimus, sorafenib, or sunitinib (p.o.). Adopted clinical response criteria for solid tumors (RECIST) were applied to classify the anti-tumor activity of the tested compounds in RCC PDX models. Next generation sequencing (NGS, panel) and transcriptome data were used to compare primary tumors and metastases. A comprehensive panel of subcutaneous RCC PDX models with well-conserved molecular and pathological features over multiple passages was established. The overall take for the RCC PDX in this study was 21%. Tumor growth characteristics were heterogeneous throughout the different models but were stable during in vivo passaging. Drug screening towards four SoC drugs, targeting the VEGF and PI3K/mTOR pathway, revealed individual and heterogeneous response profiles in the PDX, resembling the clinical situation. Intra-tumor heterogeneity can be assessed via PDX models from multi-tumor regions from one patient in our platform. Development of corresponding in vitro cell culture models from the PDX enables advanced high throughput drug screening in a personalized context. Analyzing novel targeted molecules is possible due to the pre-established molecular characterization of the PDX at the genomic and expression level. In conclusion, we established a new and molecularly characterized panel of RCC PDX models with high relevance for translational preclinical research.

Citation Format: Dennis Kobelt, Dennis Gürgen, Michael Becker, Mathias Dahlmann, Susanne Flechsig, Elke Schaeffeler, Florian A. Büttner, Christian Schmees, Regina Bohnert, Jens Bedke, Matthias Schwab, Johann J. Wendler, Martin Schostak, Burkhard Jandrig, Wolfgang Walther, Jens Hoffmann. An in vivo platform of pre-characterized renal cell carcinoma (RCC) patient-derived xenograft models allows the preclinical evaluation of patient-tailored intervention strategies [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 44.

Abstract A039: Novel tetrazolo-pyridazine based MACC1 transcriptional inhibitors as promising anti-metastatic therapy

The leading cause of cancer related deaths is the formation of metastasis, frequently caused by insufficient therapies and limited therapy options. Novel compounds able to interfere with metastasis formation are therefore of tremendous interest. Colorectal Cancer (CRC) is the third most prevalent and second most lethal cancer worldwide. In CRC, metastasis formation is linked to poor patient survival and treatment failure. Up to 90% of CRC related deaths are attributed to metastasis formation. Identification of causative drivers of metastasis represents the basis for effective anti-metastatic therapy. Our lab newly identified the gene MACC1 (Metastasis Associated in Colon Cancer 1) in 2009. Since then, MACC1 has been established as a key causal molecule for tumor progression and metastasis formation. It was shown that MACC1 can function as a stage independent prognostic marker, predicting the onset of metastasis in stages I, II and III, based on tumor tissue analyses or through a blood based test with an accuracy of up to 85%. MACC1 promotes several cancer hallmark capabilitites, providing cells with a malignant phenotype. Further, MACC1 has been established as a prognostic and predictive biomarker for metastasis in CRC and more than 20 other solid cancer entities. We therefore searched for novel compounds targeting MACC1 transcription. A high-throughput screen employing HCT116 cells stably transfected with a MACC1 promoter-luciferase reporter construct with more than 118,500 compounds was conducted at the EMBL in Heidelberg. The screen revealed a Tetrazolo-pyridazine based compound as a promising lead for effective inhibition of MACC1 expression. We demonstrated that several SAR and Medchem-generated analogues of our lead compound effectively inhibit MACC1 gene expression and MACC1 driven cancer cell motility in vitro in CRC and cross entity cell lines. Further, they inhibit MACC1-induced tumor progression and metastasis in vivo in a CRC xenograft model in mice. Moreover, ADMET studies were conducted, confirming our compounds are likely to be orally active drugs with high stability in human plasma, low plasma protein binding and great permeability with neglectable efflux in MDR1-MDCKII assay. Through RNA-sequencing and subsequent gene set enrichment analysis a first hypothesis on the mode of action was shaped. An immune pathway has been identified as the most promising signaling pathway targeted by these compounds and is currently explored through knock down and signaling studies. Taken together, this novel class of small molecules represents promising candidates for anti-metastatic therapy in CRC and other solid cancer patients in a personalized medicine setting. Funding: This study is adviced and financed by the SPARK BIH Program

Citation Format: Paul Curtis Schöpe, Shixian Yan, Dennis Kobelt, Joe Lewis, Kerstin Putzker, Ulrike Uhrig, Edgar Specker, Jens Peter von Kries, Mathias Dahlmann, Hector E Sanchez-Ibarra, Anke Unger, Mia-Lisa Zischinsky, Bert Klebl, Peter Lindemann, Wolfgang Walther, Marc Nazaré, Ulrike Stein. Novel tetrazolo-pyridazine based MACC1 transcriptional inhibitors as promising anti-metastatic therapy [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 A039.

Clinically relevant glioblastoma patient-derived xenograft models to guide drug development and identify molecular signatures

Glioblastoma (GBM) heterogeneity, aggressiveness and infiltrative growth drastically limit success of current standard of care drugs and efficacy of various new therapeutic approaches. There is a need for new therapies and models reflecting the complex biology of these tumors to analyze the molecular mechanisms of tumor formation and resistance, as well as to identify new therapeutic targets. We established and screened a panel of 26 patient-derived subcutaneous (s.c.) xenograft (PDX) GBM models on immunodeficient mice, of which 15 were also established as orthotopic models. Sensitivity toward a drug panel, selected for their different modes of action, was determined. Best treatment responses were observed for standard of care temozolomide, irinotecan and bevacizumab. Matching orthotopic models frequently show reduced sensitivity, as the blood-brain barrier limits crossing of the drugs to the GBM. Molecular characterization of 23 PDX identified all of them as IDH-wt (R132) with frequent mutations in EGFR, TP53, FAT1, and within the PI3K/Akt/mTOR pathway. Their expression profiles resemble proposed molecular GBM subtypes mesenchymal, proneural and classical, with pronounced clustering for gene sets related to angiogenesis and MAPK signaling. Subsequent gene set enrichment analysis identified hallmark gene sets of hypoxia and mTORC1 signaling as enriched in temozolomide resistant PDX. In models sensitive for mTOR inhibitor everolimus, hypoxia-related gene sets reactive oxygen species pathway and angiogenesis were enriched. Our results highlight how our platform of s.c. GBM PDX can reflect the complex, heterogeneous biology of GBM. Combined with transcriptome analyses, it is a valuable tool in identification of molecular signatures correlating with monitored responses. Available matching orthotopic PDX models can be used to assess the impact of the tumor microenvironment and blood-brain barrier on efficacy. Our GBM PDX panel therefore represents a valuable platform for screening regarding molecular markers and pharmacologically active drugs, as well as optimizing delivery of active drugs to the tumor.

Combinatorial treatment with statins and niclosamide prevents CRC dissemination by unhinging the MACC1-β-catenin-S100A4 axis of metastasis

Colorectal cancer (CRC) is the second-most common malignant disease worldwide, and metastasis is the main culprit of CRC-related death. Metachronous metastases remain to be an unpredictable, unpreventable, and fatal complication, and tracing the molecular chain of events that lead to metastasis would provide mechanistically linked biomarkers for the maintenance of remission in CRC patients after curative treatment. We hypothesized, that Metastasis-associated in colorectal cancer-1 (MACC1) induces a secretory phenotype to enforce metastasis in a paracrine manner, and found, that the cell-free culture medium of MACC1-expressing CRC cells induces migration. Stable isotope labeling by amino acids in cell culture mass spectrometry (SILAC-MS) of the medium revealed, that S100A4 is significantly enriched in the MACC1-specific secretome. Remarkably, both biomarkers correlate in expression data of independent cohorts as well as within CRC tumor sections. Furthermore, combined elevated transcript levels of the metastasis genes MACC1 and S100A4 in primary tumors and in blood plasma robustly identifies CRC patients at high risk for poor metastasis-free (MFS) and overall survival (OS). Mechanistically, MACC1 strengthens the interaction of β-catenin with TCF4, thus inducing S100A4 synthesis transcriptionally, resulting in elevated secretion to enforce cell motility and metastasis. In cell motility assays, S100A4 was indispensable for MACC1-induced migration, as shown via knock-out and pharmacological inhibition of S100A4. The direct transcriptional and functional relationship of MACC1 and S100A4 was probed by combined targeting with repositioned drugs. In fact, the MACC1-β-catenin-S100A4 axis by statins (MACC1) and niclosamide (S100A4) synergized in inhibiting cancer cell motility in vitro and metastasis in vivo. The MACC1-β-catenin-S100A4 signaling axis is causal for CRC metastasis. Selectively repositioned drugs synergize in restricting MACC1/S100A4-driven metastasis with cross-entity potential.

A Molecularly Characterized Preclinical Platform of Subcutaneous Renal Cell Carcinoma (RCC) Patient-Derived Xenograft Models to Evaluate Novel Treatment Strategies

Renal cell carcinoma (RCC) is a kidney cancer with an onset mainly during the sixth or seventh decade of the patient’s life. Patients with advanced, metastasized RCC have a poor prognosis. The majority of patients develop treatment resistance towards Standard of Care (SoC) drugs within months. Tyrosine kinase inhibitors (TKIs) are the backbone of first-line therapy and have been partnered with an immune checkpoint inhibitor (ICI) recently. Despite the most recent progress, the development of novel therapies targeting acquired TKI resistance mechanisms in advanced and metastatic RCC remains a high medical need. Preclinical models with high translational relevance can significantly support the development of novel personalized therapies. It has been demonstrated that patient-derived xenograft (PDX) models represent an essential tool for the preclinical evaluation of novel targeted therapies and their combinations. In the present project, we established and molecularly characterized a comprehensive panel of subcutaneous RCC PDX models with well-conserved molecular and pathological features over multiple passages. Drug screening towards four SoC drugs targeting the vascular endothelial growth factor (VEGF) and PI3K/mTOR pathway revealed individual and heterogeneous response profiles in those models, very similar to observations in patients. As unique features, our cohort includes PDX models from metastatic disease and multi-tumor regions from one patient, allowing extended studies on intra-tumor heterogeneity (ITH). The PDX models are further used as basis for developing corresponding in vitro cell culture models enabling advanced high-throughput drug screening in a personalized context. PDX models were subjected to next-generation sequencing (NGS). Characterization of cancer-relevant features including driver mutations or cellular processes was performed using mutational and gene expression data in order to identify potential biomarker or treatment targets in RCC. In summary, we report a newly established and molecularly characterized panel of RCC PDX models with high relevance for translational preclinical research.

MACC1-Induced Collective Migration Is Promoted by Proliferation Rather Than Single Cell Biomechanics

Metastasis-associated in colon cancer 1 (MACC1) is a marker for metastasis, tumor cell migration, and increased proliferation in colorectal cancer (CRC). Tumors with high MACC1 expression show a worse prognosis and higher invasion into neighboring structures. Yet, many facets of the pro-migratory effects are not fully understood. Atomic force microscopy and single cell live imaging were used to quantify biomechanical and migratory properties in low- and high-MACC1-expressing CRC cells. Furthermore, collective migration and expansion of small, cohesive cell colonies were analyzed using live cell imaging and particle image velocimetry. Lastly, the impact of proliferation on collective migration was determined by inhibition of proliferation using mitomycin. MACC1 did not affect elasticity, cortex tension, and single cell migration of CRC cells but promoted collective migration and colony expansion in vitro. Measurements of the local velocities in the dense cell layers revealed proliferation events as regions of high local speeds. Inhibition of proliferation via mitomycin abrogated the MACC1-associated effects on the collective migration speeds. A simple simulation revealed that the expansion of cell clusters without proliferation appeared to be determined mostly by single cell properties. MACC1 overexpression does not influence single cell biomechanics and migration but only collective migration in a proliferation-dependent manner. Thus, targeting proliferation in high-MACC1-expressing tumors may offer additional effects on cell migration.

Calcium-binding protein S100P is a new target gene of MACC1, drives colorectal cancer metastasis and serves as a prognostic biomarker

Background

The metastasis inducing gene MACC1 is a prognostic and predictive biomarker for metastasis in several cancers. Its mechanism of inducing metastasis includes the transcriptional control of other cancer-related target genes. Here, we investigate the interplay with the metastasis driver S100P in CRC progression.

Methods

MACC1-dependent S100P expression was analysed by qRT-PCR. The binding of MACC1 to the S100P promoter was determined by ChIP. Alterations in cell proliferation and motility were determined by functional in vitro assays. In vivo metastasis after intrasplenic transplantation was assessed by bioluminescence imaging and evaluation of tumour growth and liver metastasis. The prognostic value of S100P was determined in CRC patients by ROC-based Kaplan–Meier analyses.

Results

Expression of S100P and MACC1 correlated positively in CRC cells and colorectal tumours. MACC1 was found binding to the S100P promoter and induces its expression. The overexpression of S100P increased proliferation, migration and invasion in vitro and significantly induced liver metastasis in vivo. S100P expression was significantly elevated in metachronously metastasising CRC and was associated with shorter metastasis-free survival.

Conclusions

We identified S100P as a transcriptional target gene of MACC1. Expression of S100P increases the metastatic potential of CRC cells in vitro and in vivo, and serves as a prognostic biomarker for metastasis-free survival of CRC patients, emphasising novel therapeutic interventions targeting S100P.

Combination of Wnt/β-Catenin Targets S100A4 and DKK1 Improves Prognosis of Human Colorectal Cancer

Metastasis is directly linked to colorectal cancer (CRC) patient survival. Wnt signaling through β-catenin plays a key role. Metastasis-inducing S100A4 is a Wnt/β-catenin target gene and a prognostic biomarker for CRC and other cancer types. We aimed to identify S100A4-dependent expression alterations to better understand CRC progression and metastasis for improved patient survival. S100A4-induced transcriptome arrays, confirmatory studies in isogenic CRC cell lines with defined β-catenin genotypes, and functional metastasis studies were performed. S100A4-regulated transcriptome examination revealed the transcriptional cross-regulation of metastasis-inducing S100A4 with Wnt pathway antagonist Dickkopf-1 (DKK1). S100A4 overexpression down-regulated DKK1, S100A4 knock-down increased DKK1. Recombinant DKK1 reduced S100A4 expression and S100A4-mediated cell migration. In xenografted mice, systemic S100A4-shRNA application increased intratumoral DKK1. The inverse correlation of S100A4 and DKK1 was confirmed in five independent publicly available CRC expression datasets. Combinatorial analysis of S100A4 and DKK1 in two additional independent CRC patient cohorts improved prognosis of overall and metastasis-free survival. The newly discovered transcriptional cross-regulation of Wnt target S100A4 and Wnt antagonist DKK1 is predominated by an S100A4-induced Wnt signaling feedback loop, increasing cell motility and metastasis risk. S100A4 and DKK1 combination improves the identification of CRC patients at high risk.

MACC1 regulates clathrin-mediated endocytosis and receptor recycling of transferrin receptor and EGFR in colorectal cancer

Metastasis Associated in Colon Cancer 1 (MACC1) is a novel prognostic, predictive and causal biomarker for tumor progression and metastasis in many cancer types, including colorectal cancer. Besides its clinical value, little is known about its molecular function. Its similarity to SH3BP4, involved in regulating uptake and recycling of transmembrane receptors, suggests a role of MACC1 in endocytosis. By exploring the MACC1 interactome, we identified the clathrin-mediated endocytosis (CME)-associated proteins CLTC, DNM2 and AP-2 as MACC1 binding partners. We unveiled a MACC1-dependent routing of internalized transferrin receptor towards recycling. Elevated MACC1 expression caused also the activation and internalization of EGFR, a higher rate of receptor recycling, as well as earlier and stronger receptor activation and downstream signaling. These effects are limited by deletion of CME-related protein interaction sites in MACC1. Thus, MACC1 regulates CME and receptor recycling, causing increased growth factor-mediated downstream signaling and cell proliferation. This novel mechanism unveils potential therapeutic intervention points restricting MACC1-driven metastasis.

MACC1 driven alterations in cellular biomechanics facilitate cell motility in glioblastoma

Background

Metastasis-associated in colon cancer 1 (MACC1) is an established marker for metastasis and tumor cell migration in a multitude of tumor entities, including glioblastoma (GBM). Nevertheless, the mechanism underlying the increased migratory capacity in GBM is not comprehensively explored.

Methods

We performed live cell and atomic force microscopy measurements to assess cell migration and mechanical properties of MACC1 overexpressing GBM cells. We quantified MACC1 dependent dynamics of 3D aggregate formation. For mechanistic studies we measured the expression of key adhesion molecules using qRT-PCR, and MACC1 dependent changes in short term adhesion to fibronectin and laminin. We then determined changes in sub-cellular distribution of integrins and actin in dependence of MACC1, but also in microtubule and intermediate filament organization.

Results

MACC1 increased the migratory speed and elastic modulus of GBM cells, but decreased cell-cell adhesion and inhibited the formation of 3D aggregates. These effects were not associated with altered mRNA expression of several key adhesion molecules or altered short-term affinity to laminin and fibronectin. MACC1 did neither change the organization of the microtubule nor intermediate filament cytoskeleton, but resulted in increased amounts of protrusive actin on laminin.

Conclusion

MACC1 overexpression increases elastic modulus and migration and reduces adhesion of GBM cells thereby impeding 3D aggregate formation. The underlying molecular mechanism is independent on the organization of microtubules, intermediate filaments and several key adhesion molecules, but depends on adhesion to laminin. Thus, targeting re-organization of the cytoskeleton and cell motility via MACC1 may offer a treatment option to impede GBM spreading.

Restoring Treatment Response in Colorectal Cancer Cells by Targeting MACC1-Dependent ABCB1 Expression in Combination Therapy

Treatment failure of solid cancers, represented by the development of drug resistance in the primary tumor or later outgrowth of drug resistant metastases, is the major cause of death for cancer patients. It represents an urgent clinical need for predictive biomarkers which indicate the success or failure of standard treatment regimens. Besides treatment prediction, interfering with cellular processes associated with drug resistance might improve treatment response by applying combination therapies. Metastasis-associated in colon cancer (MACC) 1 was identified in our group as a prognostic biomarker in human colorectal cancer, and has been established as key player, prognostic, and predictive biomarker for tumor progression and metastasis in a variety of solid cancers. Besides increased cell proliferation and motility, subsequently contributing to growth and metastatic spread of the primary tumor, MACC1 has also been shown to dysregulate apoptosis and is contributing to treatment resistance. Here we report the MACC1 dependent treatment resistance of colorectal cancer (CRC) cells to standard therapeutics like doxorubicin by upregulating ATP-binding cassette subfamily B member 1 (ABCB1) protein. Overexpression of MACC1 in CRC cells increased both its presence on the ABCB1 promoter and its transcriptional activity, resulting in elevated ABCB1 expression and thus treatment resistance to standard therapeutics. In contrast, depleting MACC1 increased intracellular drug concentrations, leading to better treatment response. We already identified the first MACC1 transcriptional inhibitors, such as lovastatin, by high-throughput screening of clinically approved small molecule drugs. These compounds inhibited cell motility in vitro but also restricted metastasis development in xenograft mouse models by reducing MACC1 expression. Here we report, that treating high MACC1 expressing CRC cells with a combination of statins and standard therapeutics increased the rate of cytotoxicity and resulted in higher treatment response.

Abstract 2000: Cancer metastasis driven by the novel MEK1 substrate MACC1 is restricted by clinically applicable MEK1 inhibitors

Cancer metastasis is responsible for >90% of cancer deaths and remains a major treatment challenge. In search of new drivers of metastasis we identified the novel, previously undescribed gene Metastasis-Associated in Colon Cancer 1 (MACC1) in human colorectal cancer (CRC). MACC1 induces fundamental processes like proliferation, migration, invasiveness and metastasis in xenografted and transgenic mice. MACC1 has been established by us and many other groups as key player, prognostic and predictive biomarker for tumor progression and metastasis in >20 solid cancer types. Proof-of-concept for MACC1 as a therapeutic target to restrict cancer progression and metastasis was provided by transcriptional and post-transcriptional downregulation of MACC1 for several solid cancers, including CRC. Specific inhibitors targeting MACC1 post-translational protein modifications to restrict tumor growth and metastasis are not identified so far. Here we report the identification of MACC1 as a newly identified substrate of the kinase MEK1 (MAP2K1). MEK1 directly phosphorylates MACC1 leading to accelerated and increased ERK1 activation. Mutating three potential hierarchical MACC1 tyrosine phosphorylation sites abrogates MACC1 dependent target gene expression like MET, cell proliferation and motility in cell culture and importantly, metastasis in mouse xenograft models. Targeting MEK1 by RNAi or by clinically applicable MEK1 inhibitors like AZD6244 and GSK1120212 reduces MACC1 tyrosine phosphorylation and restricts MACC1-induced metastasis formation. Our findings demonstrate that MAP kinase signaling is not linearly leading only to ERK activation, but branches at the level of MEK1. In summary, MACC1 tyrosine phosphorylation is decisive for tumor growth and metastasis. The fundamental finding of MACC1 being a newly identified MEK1 substrate opens new therapeutic options with potential for clinical translation. Targeting MACC1 tyrosine phosphorylation using MEK1 inhibitors thereby intervening in MACC1-induced metastasis aims at the ultimate goal of personalized therapies for inhibition of cancer progression and metastasis, resulting in improved patient survival. Since MACC1 is confirmed as decisive driver for tumor growth and metastasis in a variety of solid cancers, the findings made here for CRC might be translated to further solid tumor types. The usefulness of MACC1 as therapeutic target towards MEK1 inhibitor treatment requires confirmation in clinical trials.

Citation Format: Dennis Kobelt, Daniel Perez-Hernandez, Claudia Fleuter, Mathias Dahlmann, Fabian Zincke, Janice Smith, Rebekka Migotti, Susen Burock, Wolfgang Walther, Gunnar Dittmar, Ulrike S. Stein. Cancer metastasis driven by the novel MEK1 substrate MACC1 is restricted by clinically applicable MEK1 inhibitors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 2000.

Circulating MACC1 Transcripts in Glioblastoma Patients Predict Prognosis and Treatment Response

Glioblastoma multiforme is the most aggressive primary brain tumor of adults, but lacks reliable and liquid biomarkers. We evaluated circulating plasma transcripts of metastasis-associated in colon cancer-1 (MACC1), a prognostic biomarker for solid cancer entities, for prediction of clinical outcome and therapy response in glioblastomas. MACC1 transcripts were significantly higher in patients compared to controls. Low MACC1 levels clustered together with other prognostically favorable markers. It was associated with patients’ prognosis in conjunction with the isocitrate dehydrogenase (IDH) mutation status: IDH1 R132H mutation and low MACC1 was most favorable (median overall survival (OS) not yet reached), IDH1 wildtype and high MACC1 was worst (median OS 8.1 months), while IDH1 wildtype and low MACC1 was intermediate (median OS 9.1 months). No patients displayed IDH1 R132H mutation and high MACC1. Patients with low MACC1 levels receiving standard therapy survived longer (median OS 22.6 months) than patients with high MACC1 levels (median OS 8.1 months). Patients not receiving the standard regimen showed the worst prognosis, independent of MACC1 levels (low: 6.8 months, high: 4.4 months). Addition of circulating MACC1 transcript levels to the existing prognostic workup may improve the accuracy of outcome prediction and help define more precise risk categories of glioblastoma patients.

MACC1-the first decade of a key metastasis molecule from gene discovery to clinical translation

Deciphering the paths to metastasis and identifying key molecules driving this process is one important issue for understanding and treatment of cancer. Such a key driver molecule is Metastasis Associated in Colon Cancer 1 (MACC1). A decade long research on this evolutionarily conserved molecule with features of a transcription factor as well as an adapter protein for versatile protein-protein interactions has shown that it has manifold properties driving tumors to their metastatic stage. MACC1 transcriptionally regulates genes involved in epithelial-mesenchymal transition (EMT), including those which are able to directly induce metastasis like c-MET, impacts tumor cell migration and invasion, and induces metastasis in solid cancers. MACC1 has proven as a valuable biomarker for prognosis of metastasis formation linked to patient survival and gives promise to also act as a predictive marker for individualized therapies in a broad variety of cancers. This review discusses the many features of MACC1 in the context of the hallmarks of cancer and the potential of this molecule as biomarker and novel therapeutic target for restriction and prevention of metastasis.

Expression of activating transcription factor 5 (ATF5) is increased in astrocytomas of different WHO grades and correlates with survival of glioblastoma patients

Background

ATF5 suppresses differentiation of neuroprogenitor cells and is overexpressed in glioblastoma (GBM). A reduction of its expression leads to apoptotic GBM cell death. Data on ATF5 expression in astrocytoma WHO grade II (low-grade astrocytoma [LGA]) are scarce and lacking on recurrent GBM.

Patients and methods

ATF5 mRNA was extracted from frozen samples of patients’ GBM (n=79), LGA (n=40), and normal brain (NB, n=10), quantified by duplex qPCR and correlated with retrospectively collected clinical data. ATF5 protein expression was evaluated by measuring staining intensity on immunohistochemistry.

Results

ATF5 mRNA was overexpressed in LGA (sevenfold, P<0.001) and GBM (tenfold, P<0.001) compared to NB, which was confirmed on protein level. Although ATF5 mRNA expression in GBM showed a considerable fluctuation range, groups of varying biological behavior, that is, local/multifocal growth or primary tumor/relapse and the tumor localization at diagnosis, were not significantly different. ATF5 mRNA correlated with the patients’ age (r=0.339, P=0.028) and inversely with Ki67-staining (r=−0.421, P=0.007). GBM patients were allocated to a low and a high ATF5 expression group by the median ATF5 overexpression compared to NB. Kaplan–Meier analysis and Cox regression indicated that ATF5 mRNA expression significantly correlated with short-term survival (t,12 months, median survival 18 vs 13 months, P=0.022, HR 2.827) and progression-free survival (PFS) (12 vs 6 months, P=0.024). This advantage vanished after 24 months (P=0.084).

Conclusion

ATF5 mRNA expression could be identified as an additional, though not independent factor correlating with overall survival and PFS. Since its inhibition might lead to the selective death of glioma cells, it might serve as a potential ubiquitous therapeutic target in astrocytic tumors.

Abstract 4099: Novel patient-derived 3D (PD3D) cell models and matched patient-derived xenografts (PDX) from peritoneal metastasis of colorectal cancer for drug testing and biomarker analysis

For patients with colorectal cancer (CRC) peritoneal metastases (PM) represent a terminal tumor stage with limited therapeutic options. To increase therapeutic efficacy and overall survival, availability of appropriate patient-derived 3D cell culture (PD3D) and patient-derived xenografts (PDX) models of PM could help improving the predictability of drug response for a specific tumor, but also foster the identification of novel biomarkers and therapeutic targets for CRC-PM patients. In this context, we generated the first scaffold-based PD3D and matching PDX models of CRC-PM as platform to test for chemotherapy response and to identify novel biomarkers.

For model establishment, surgical specimens were processed either for PD3D cell culture or transplanted subcutaneously (s.c.) onto immunocompromized NOD scid gamma (NSG) mice. For 3D cell culture models, tissue was dissected, digested and filtered before embedding into a scaffold matrix. For PDX models engrafted tumors were transferred to NMRI nu/nu mice for further passaging. They were characterized by histopathology, immunohistochemistry and gene expression analyses using real-time RT-PCR. Chemosensitivity of both sibling models was evaluated on a panel of conventional chemotherapeutic and of targeted drugs.

The same panel of drugs was used in 15 matched PD3D/PDX models and revealed individual response patterns both in PD3D and PDX. Most interestingly, different drug response pattern was observed in models derived from tumor tissue of the omentum vs. tissue from the peritoneum of the same patient.

Our results demonstrate, that matched models maintain basic characteristics such as the morphology of the patient tumor in early passages, reflect heterogeneous response rates, and can be used as preclinical platform for translational studies of potential clinical use.

Citation Format: Christian RA Regenbrecht, Guido Gambara, Eva Pachmayr, Alessandra Silvestri, Mathias Dahlmann, Bernadette Brzezicha, Britta Buettner, Beate Rau, Ulrich Keilholz, Urike Stein, Wolfgang Walther. Novel patient-derived 3D (PD3D) cell models and matched patient-derived xenografts (PDX) from peritoneal metastasis of colorectal cancer for drug testing and biomarker analysis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4099.

Statin and rottlerin small-molecule inhibitors restrict colon cancer progression and metastasis via MACC1

MACC1 (Metastasis Associated in Colon Cancer 1) is a key driver and prognostic biomarker for cancer progression and metastasis in a large variety of solid tumor types, particularly colorectal cancer (CRC). However, no MACC1 inhibitors have been identified yet. Therefore, we aimed to target MACC1 expression using a luciferase reporter-based high-throughput screening with the ChemBioNet library of more than 30,000 compounds. The small molecules lovastatin and rottlerin emerged as the most potent MACC1 transcriptional inhibitors. They remarkably inhibited MACC1 promoter activity and expression, resulting in reduced cell motility. Lovastatin impaired the binding of the transcription factors c-Jun and Sp1 to the MACC1 promoter, thereby inhibiting MACC1 transcription. Most importantly, in CRC-xenografted mice, lovastatin and rottlerin restricted MACC1 expression and liver metastasis. This is-to the best of our knowledge-the first identification of inhibitors restricting cancer progression and metastasis via the novel target MACC1. This drug repositioning might be of therapeutic value for CRC patients.

Abstract 4119: Tyrosine phosphorylation of MACC1 is essential and druggable for colorectal cancer metastasis restriction

We identified the previously undescribed gene Metastasis Associated in Colon Cancer 1 (MACC1). MACC1 is a metastasis inducer and prognostic biomarker for colorectal cancer (CRC). MACC1 has meanwhile been confirmed as decisive driver for tumorigenesis and metastasis for a broad variety of solid cancers. Here we aim to identify the impact of defined tyrosine phosphorylations on the function of the metastasis inducer MACC1.

In silico identified MACC1 tyrosine phosphorylation (pY) sites were ranked and most promising positions were site-directed mutated in wildtype (wt) MACC1 constructs. Human CRC cells were transduced with these constructs. Tyrosine phosphorylation was quantified by selected reaction monitoring (SRM)-mass spectrometry. Effects of pY-MACC1 mutants on cell migration, proliferation, dissemination and colony formation were assessed in cell culture as well as on liver metastasis formation in human CRC-xenografted mice. To identify MACC1-phosphorylating kinases the MACC1 interactome was identified using mass spectrometry. Most promising binding partners were validated by immunoprecipitation. Impact of inhibitors targeting kinases phosphorylating MACC1 was assessed on MACC1-induced tumor growth and liver metastasis in human CRC-xenografted mice by in vivo imaging.

We report that tyrosine phosphorylation of MACC1 is hierarchical and essential for motility and proliferation in cell culture, as well as for tumor growth and metastasis in mice. We identified kinases for MACC1 phosphorylation. Targeting these kinases using inhibitors employed in clinical trials restricts MACC1-induced tumor growth and metastasis in mice.

MACC1 tyrosine phosphorylation is crucial for metastasis and is druggable by small molecule inhibitors. This fundamental finding opens new therapeutic options for inhibition of MACC1-induced cancer metastasis.

Citation Format: Dennis Kobelt, Gunnar Dittmar, Claudia Fleuter, Janice Smith, Mathias Dahlmann, Rebekka Migotti, Peter M. Schlag, Ulrike S. Stein. Tyrosine phosphorylation of MACC1 is essential and druggable for colorectal cancer metastasis restriction. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 4119. doi:10.1158/1538-7445.AM2015-4119

RAGE Mediates the Pro-Migratory Response of Extracellular S100A4 in Human Thyroid Cancer Cells

BACKGROUND

Expression of the small calcium-binding protein S100A4 is associated with poor prognosis in patients with thyroid cancer (TC). The authors have previously shown that S100A4 is a target for relaxin and insulin-like peptide 3 signaling in TC cells and that S100A4 is secreted from human TC cells. Although the pro-migratory role of intracellular S100A4 in binding to non-muscle myosin is well known, this study investigated here whether extracellular S100A4 contributes to TC migration.

METHODS

Human cell lines of follicular, papillary, and undifferentiated thyroid cancer, primary patient TC cells, and TC tissues were utilized to discover the presence of the receptor of advanced glycation end products (RAGE) in TC cells and TC tissues. Fluorescence imaging, protein pull-down assays, Western blot, siRNA protein silencing, small GTPase inhibitors, cell proliferation, and cell migration assays were used to investigate the interaction of extracellular S100A4 with RAGE in promoting a TC migratory response.

RESULTS

It was demonstrated that RAGE served as receptor for extracellular S100A4 mediating cell migration in TC cells. The RAGE-mediated increase in cell migration was dependent on the intracellular RAGE signaling partner diaphanous-1 (Dia-1) and involved the activation of the small GTPases Cdc42 and RhoA. Although extracellular S100A4 consistently activated ERK signaling in TC cells, it was shown that ERK signaling was not mediated by RAGE and not essential for the migratory response in TC cells.

CONCLUSION

The data have identified the RAGE/Dia-1 signaling system as a mediator for the pro-migratory response of extracellular S100A4 in human TC. Thus, therapeutic targeting of the RAGE/Dia-1/small GTPases signaling may successfully reduce local invasion and metastasis in TC.

RNA Interference for Antimetastatic Therapy

The suppression of genes involved in tumor progression, metastasis formation, or therapy resistance by RNA interference is a promising tool to treat cancer disease. Efficient delivery of interfering molecules and their sustained presence in tumor cells are required for therapeutic success. This chapter describes a method of systemic application of shRNA expression plasmid via tail vein injection in xenograft mice, causing the sustained reduction of target gene expression in the primary tumor. By choosing S100A4 as a metastasis driving target gene, this therapeutic approach restricted the formation of distant colorectal cancer metastases after intrasplenic transplantation. In vivo imaging of bioluminescent cancer cells allows the monitoring of tumor growth and metastasis formation over time. End point analysis of the trial included scoring of the metastatic burden and the quantification of target gene expression in the tumor. Average S100A4 expression in tumor tissues was reduced by 30 %, causing a 70 % decrease of liver metastases.

Systemic shRNA mediated knock down of S100A4 in colorectal cancer xenografted mice reduces metastasis formation

The metastasis-inducing protein S100A4 was found to be a prognostic indicator for the development of metachronous metastases. S100A4 expression levels correlate with the formation of human colorectal cancer metastases and shorter patients’ survival. Inhibition of S100A4 expression in patients might therefore result in decreased metastasis formation and prolonged survival. In the present study, we used shRNA expression plasmids to inhibit S100A4 expression in the colorectal cancer cell lines HCT116, SW620 and DLD-1. Cell lines with reduced S100A4 expression showed reduced cell migration and invasion in vitro. The knock-down of S100A4 expression also led to significantly diminished formation of liver metastases when intrasplenically transplanted in mice (P = 0.004). We then focused on the therapeutic potential of systemically applied shRNA expression plasmids acting on S100A4 via repeated hydrodynamics-based tail vein injection of plasmid DNA. Mice, intrasplenically transplanted with HCT116 cells and treated systemically with S100A4-shRNA plasmids, showed a decrease of S100A4 and MMP9 expression levels, resulting in significantly reduced liver metastases (P = 0.005). In summary, we show for the first time the intratumoral knock-down of S100A4 via systemic application of S100A4-shRNA plasmid DNA, which restricts metastasis formation in a xenografted mouse model of colorectal cancer.

Subcellular compartmentation and differential catalytic properties of the three human nicotinamide mononucleotide adenylyltransferase isoforms

Nicotinamide mononucleotide adenylyltransferase (NMNAT) is the central enzyme of the NAD biosynthetic pathway. Three human NMNAT isoforms have recently been identified, but isoform-specific functions are presently unknown, although a tissue-specific role has been suggested. Analyses of the subcellular localization confirmed NMNAT1 to be a nuclear protein, whereas NMNAT2 and -3 were localized to the Golgi complex and the mitochondria, respectively. This differential subcellular localization points to an organelle-specific, nonredundant function of each of the three proteins. Comparison of the kinetic properties showed that particularly NMNAT3 exhibits a high tolerance toward substrate modifications. Moreover, as opposed to preferred NAD+ synthesis by NMNAT1, the other two isoforms could also form NADH directly from the reduced nicotinamide mononucleotide, supporting a hitherto unknown pathway of NAD generation. A variety of physiological intermediates was tested and exerted only minor influence on the catalytic activities of the NMNATs. However, gallotannin was found to be a potent inhibitor, thereby compromising its use as a specific inhibitor of poly-ADP-ribose glycohydrolase. The presence of substrate-specific and independent nuclear, mitochondrial, and Golgi-specific NAD biosynthetic pathways is opposed to the assumption of a general cellular NAD pool. Their existence appears to be consistent with important compartment-specific functions rather than to reflect simple functional redundance.

Palladium-catalyzed sequential alkylation-alkenylation reactions and their application to the synthesis of fused aromatic rings

The synthesis of fused aromatic carbocycles from aryl iodides and difunctional acceptors is outlined. This methodology is based on a palladium-catalyzed aromatic substitution followed by an intramolecular Heck sequence. Under the optimized conditions (Pd(OAc)(2) (10 mol %), tri-2-furylphosphine (20-30 mol %), norbornene (2 equiv), Cs(2)CO(3) (2 equiv), CH(3)CN, reflux), bromoenoates react with aryl iodides bearing numerous substituents (F, Cl, CF(3), Me, etc.). The expanded description of our initial work as well as the use of polysubstituted aryl iodides is described.

Risk factors for urinary lithotripsy-associated sepsis

OBJECTIVES

To identify risk factors for sepsis following urinary extracorporeal shock wave lithotripsy (ESWL).

DESIGN

Retrospective case-control study with two control groups.

SETTING

A rural, 570-bed, regional referral center.

RESULTS

Six cases (four bacteremias and two fungemias) were compared with two sets of 18 controls. Cases had a higher frequency and number of urinary tract infections prior to the procedure and tended to have larger stone size.

CONCLUSIONS

Patients undergoing ESWL who are at high risk for infectious complications may be identified by preprocedure evaluation. Such patients may require alternative prophylactic regimens and close postprocedure follow-up.