Cell migration driven by actomyosin filament assembly is a critical step in tumour invasion and metastasis. Herein, we report identification of myosin binding protein H (MYBPH) as a transcriptional target of TTF-1 (also known as NKX2-1 and TITF1), a master regulator of lung development that also plays a role as a lineage-survival oncogene in lung adenocarcinoma development. MYBPH inhibited assembly competence-conferring phosphorylation of the myosin regulatory light chain (RLC) as well as activating phosphorylation of LIM domain kinase (LIMK), unexpectedly through its direct physical interaction with Rho kinase 1 (ROCK1) rather than with RLC. Consequently, MYBPH inhibited ROCK1 and negatively regulated actomyosin organization, which in turn reduced single cell motility and increased collective cell migration, resulting in decreased cancer invasion and metastasis. Finally, we also show that MYBPH is epigenetically inactivated by promoter DNA methylation in a fraction of TTF-1-positive lung adenocarcinomas, which appears to be in accordance with its deleterious functions in lung adenocarcinoma invasion and metastasis, as well as with the paradoxical association of TTF-1 expression with favourable prognosis in lung adenocarcinoma patients.

Vascular smooth muscle cells (VSMCs) have two distinct phenotypes: contractile and synthetic. The major difference between these phenotypes lies in the magnitude of the contractile force produced by the cell. Although traction force microscopy (TFM) is often used to evaluate cellular contractile force, this method requires complex preprocessing and a sufficiently compliant substrate. To evaluate the contractile force and the phenotype of living VSMCs with minimal effort and in a manner independent of the substrate stiffness, we propose a photoelasticity-based method using retardation, which is related to the difference between the first and second principal stresses and their orientation. The results demonstrate that actin filaments co-localize with areas of high retardation in cells, indicating that the retardation of VSMCs is promoted by actin filaments. The retardation of cells treated with calyculin A and Y-27632 tended to be larger and smaller, respectively, than that of control cells. Cell traction force significantly correlates with total cell retardation ( r 2 = 0.38). The retardation of contractile VSMCs (passage 2) was significantly higher than that of synthetic VSMCs (passage 12). These results indicate that cell retardation can be used to assess cell contractile force and, thus, determine the phenotype of VSMCs.

Background The most common adverse event (AE) associated with opioid analgesics is opioid-induced constipation (OIC). Naldemedine (NAL) is widely used for the treatment of OIC. However, diarrhea has been reported as the most common treatment-emergent AE of NAL, and little is known about the risk factors associated with the development of diarrhea during NAL administration. This study examined the risk factors for NAL-induced diarrhea via a retrospective chart review of hospitalized patients. Methods The data of 101 hospitalized adult patients who received NAL for the first time for the treatment of OIC at Mie University Hospital between June 2017 and December 2018 were extracted from electronic medical records. According to the inclusion and exclusion criteria, 70 of the 101 patients were enrolled in this study. Diarrhea was defined as “diarrhea” on the medical record within 2 weeks of NAL administration. Univariate and multivariate analyses were performed to identify risk factors for the development of diarrhea in patients receiving NAL. Results Twenty-two of the 70 patients enrolled (31%) developed diarrhea within 2 weeks of NAL administration. The median duration (range) of NAL treatment before diarrhea onset was 3 (1–12) days. Patients with diarrhea had a significantly longer duration of opioid therapy before NAL administration than patients without diarrhea (P=0.002). Multivariate logistic regression analysis indicated that the independent risk factors for the development of NAL-induced diarrhea were NAL administration after more than 17 days of opioid therapy (odds ratio [OR]=7.539; P=0.016) and pancreatic cancer (OR=6.217; P=0.025). In fact, the incidence of diarrhea in patients who were administered NAL within a day of opioid therapy was significantly lower than that in patients who were administered NAL after more than 17 days of opioid therapy (13% vs. 54%, P=0.030). Conclusions These results suggested that a prolonged duration of opioid therapy prior to NAL initiation is associated with increased incidence of diarrhea.

Lung cancer is the leading cause of cancer death in most economically developed countries, with lung adenocarcinoma the most prevalent form. The vast majority of lung cancer-related deaths is caused by invasion and metastasis, thus it is crucially important to elucidate the underlying mechanisms. We previously reported that lung adenocarcinomas are addicted to sustained expression of TTF-1 (also know as NKX2–1 and TITF1), a lineage-specific transcription factor required for branching morphogenesis and physiological lung functions, while others subsequently reached similar conclusions in studies that used genome-wide searches for focal genomic aberrations in lung adenocarcinomas. However, TTF-1/NKX2–1 expression is paradoxically known to be associated with favourable prognosis in lung adenocarcinoma cases. Emerging evidence indicates that non-muscle myosin II (NM II) members, especially NM IIA, are crucially involved in cancer cell migration, invasion, and metastasis via bivalent binding to actin filaments. Rho kinase 1 (ROCK1), a downstream effecter of RhoA, has been shown to be a major positive regulator of that process, which is thought to be executed through phosphorylation of myosin regulatory light chain (RLC) and subsequent unfolding of NM IIA into an assembly competent form capable of NM IIA dimer formation. In addition, ROCK1 phosphorylates LIM domain kinase (LIMK) and stabilizes actin filaments through inactivation of the actin-depolymerising factor cofilin. However, how actomyosin organization in non-muscle cells is regulated to counter-balance the positive regulatory function of ROCK1 remains to be elucidated. Herein, we report identification of myosin binding protein H (MYBPH) as a transcriptional target of TTF-1/NKX2–1, a lineage-survival oncogene in lung adenocarcinoma. MYBPH inhibits assembly competence-conferring phosphorylation of RLC as well as activating phosphorylation of LIMK. These are unexpectedly implemented through direct physical interaction of MYBPH with ROCK1 rather than with RLC, leading to inhibition of the ROCK1 kinase activity. In addition, MYBPH is shown to directly bind with non-muscle myosin heavy chain IIA (NMHC IIA), resulting in inhibition of NMHC IIA assembly. Thus, the present findings demonstrate that MYBPH plays multi-facetted roles in negative regulation of actomyosin organization, which we find results in reduction of cell motility, invasion, and metastasis. Finally, we also show that MYBPH is epigenetically inactivated by promoter DNA methylation in a fraction of lung adenocarcinomas abundantly expressing TTF-1/NKX2–1, which appears to be in accordance with its deleterious function for lung adenocarcinoma invasion and metastasis, as well as with the paradoxical association of TTF-1/NKX2–1 expression with favourable prognosis in lung adenocarcinoma patients. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr LB-360. doi:10.1158/1538-7445.AM2011-LB-360

No abstract