Discovery of tetrazolo-pyridazine-based small molecules as inhibitors of MACC1-driven cancer metastasis

Metastasis is directly linked to poor prognosis of cancer patients and warrants search for effective anti-metastatic drugs. MACC1 is a causal key molecule for metastasis. High MACC1 expression is prognostic for metastasis and poor survival. Here, we developed novel small molecule inhibitors targeting MACC1 expression to impede metastasis formation. We performed a human MACC1 promoter-driven luciferase reporter-based high-throughput screen (HTS; 118.500 compound library) to identify MACC1 transcriptional inhibitors. HTS revealed 1,2,3,4-tetrazolo[1,5-b]pyridazine-based compounds as efficient transcriptional inhibitors of MACC1 expression, able to decrease MACC1-induced cancer cell motility in vitro. Structure-activity relationships identified the essential inhibitory core structure. Best candidates were evaluated for metastasis inhibition in xenografted mouse models demonstrating metastasis restriction. ADMET showed high drug-likeness of these new candidates for cancer therapy. The NFκB pathway was identified as one mode of action targeted by these compounds. Taken together, 1,2,3,4-tetrazolo[1,5-b]pyridazine-based compounds are effective MACC1 inhibitors and pose promising candidates for anti-metastatic therapies particularly for patients with MACC1-overexpressing cancers, that are at high risk to develop metastases. Although further preclinical and clinical development is necessary, these compounds represent important building blocks for an individualized anti-metastatic therapy for solid cancers.

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.

Cantharidin and Its Analogue Norcantharidin Inhibit Metastasis-Inducing Genes S100A4 and MACC1

Colorectal cancer (CRC) is the third most prevalent and second deadliest cancer worldwide. In addition, metastasis directly causes up to 90% of all CRC deaths, highlighting the metastatic burden of the disease. Biomarkers such as S100A4 and MACC1 aid in identifying patients with a high risk of metastasis formation. High expression of S100A4 or MACC1 and to a greater extent the combination of both biomarkers is a predictor for metastasis and poor patient survival in CRC. MACC1 is a tumor-initiating and metastasis-promoting oncogene, whereas S100A4 has not been shown to initiate tumor formation but can, nevertheless, promote malignant tumor growth and metastasis formation. Cantharidin is a natural drug extracted from various blister beetle species, and its demethylated analogue norcantharidin has been shown in several studies to have an anti-cancer and anti-metastatic effect in different cancer entities such as CRC, breast cancer, and lung cancer. The impact of the natural compound cantharidin and norcantharidin on S100A4 and MACC1 gene expression, cancer cell migration, motility, and colony formation in vitro was tested. Here, for the first time, we have demonstrated that cantharidin and norcantharidin are transcriptional inhibitors of S100A4 and MACC1 mRNA expression, protein expression, and motility in CRC cells. Our results clearly indicate that cantharidin and, to a lesser extent, its analogue norcantharidin are promising compounds for efficient anti-metastatic therapy targeting the metastasis-inducing genes S100A4 and MACC1 for personalized medicine for cancer patients.