MACC1 Regulates LGR5 to Promote Cancer Stem Cell Properties in Colorectal Cancer.

Colorectal cancer (CRC) is one of the leading causes of cancer-related deaths worldwide. The high mortality is directly associated with metastatic disease, which is thought to be initiated by colon cancer stem cells, according to the cancer stem cell (CSC) model. Consequently, early identification of those patients who are at high risk for metastasis is crucial for improved treatment and patient outcomes. Metastasis-associated in colon cancer 1 (MACC1) is a novel prognostic biomarker for tumor progression and metastasis formation independent of tumor stage. We previously showed an involvement of MACC1 in cancer stemness in the mouse intestine of our MACC1 transgenic mouse models. However, the expression of MACC1 in human CSCs and possible implications remain elusive. Here, we explored the molecular mechanisms by which MACC1 regulates stemness and the CSC-associated invasive phenotype based on patient-derived tumor organoids (PDOs), patient-derived xenografts (PDXs) and human CRC cell lines. We showed that CD44-enriched CSCs from PDO models express significantly higher levels of MACC1 and LGR5 and display higher tumorigenicity in immunocompromised mice. Similarly, RNA sequencing performed on PDO and PDX models demonstrated significantly increased MACC1 expression in ALDH1(+) CSCs, highlighting its involvement in cancer stemness. We further showed the correlation of MACC1 with the CSC markers CD44, NANOG and LGR5 in PDO models as well as established cell lines. Additionally, MACC1 increased stem cell gene expression, clonogenicity and sphere formation. Strikingly, we showed that MACC1 binds as a transcription factor to the LGR5 gene promoter, uncovering the long-known CSC marker LGR5 as a novel essential signaling mediator employed by MACC1 to induce CSC-like properties in human CRC patients. Our in vitro findings were further substantiated by a significant positive correlation of MACC1 with LGR5 in CRC cell lines as well as CRC patient tumors. Taken together, this study indicates that the metastasis inducer MACC1 acts as a cancer stem cell-associated marker. Interventional approaches targeting MACC1 would potentially improve further targeted therapies for colorectal cancer patients to eradicate CSCs and prevent cancer recurrence and distant metastasis formation.

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.

Epidemiological and clinical characteristics and management of oropharyngeal tularemia outbreak.

BACKGROUND/AIM: The purpose of this study was to determine the epidemiological and clinical characteristics of patients diagnosed with tularemia and the effectiveness of the administered treatments. MATERIALS AND METHODS: Patients treated in our hospital between January 2009 and March 2011 and diagnosed with tularemia were evaluated retrospectively. Patients' epidemiological and clinical characteristics, administered treatments, and posttreatment findings were recorded on patient monitoring forms. RESULTS: At anamnesis, 29% of patients used water from wells and 71% used water from the network supply; moreover, 48.4% had a history of contact with animals and 87.1% a history of lethargy. At physical examination, 96.8% had a mass in the neck and 90.3% had fever. Gentamycin + doxycycline therapy was administered to 45.2% of patients, while levofloxacin, gentamycin, and streptomycin were used for the other patients. After treatment, neck masses persisted in 48.4% of patients and complaints of lethargy and fever in 6.5%. Treatment of these patients was initiated once tularemia had been diagnosed, as test results were announced about 3 weeks later. Lymphadenopathy excision was performed on 19.4% of patients in whom neck mass persisted. CONCLUSION: Appropriate empiric antibiotherapy should be commenced in patients presenting with neck mass, fever, and lethargy in regions with tularemia epidemics.