Pancreatic ductal adenocarcinoma (PDAC) is among the cancers with the poorest prognoses due to its highly malignant features. BTB and CNC homology 1 (BACH1) has been implicated in RAS-driven tumor formation. We focused on the role of BACH1 in PDAC, more than 90% of which have KRAS mutation. Knockdown of BACH1 in PDAC cell lines reduced cell migration and invasion, in part, by increasing E-cadherin expression, whereas its overexpression showed opposite effects. BACH1 directly repressed the expression of FOXA1 that is known to activate the expression of CDH1 encoding E-cadherin and to inhibit epithelial-to-mesenchymal transition. BACH1 also directly repressed the expression of genes important for epithelial cell adhesion including CLDN3 and CLDN4. In a mouse orthotopic implantation model, BACH1 was required for the high metastatic ability of AsPC-1 cells. IHC analysis of clinical specimens with a newly developed anti-BACH1 mAb revealed that high expression of BACH1 is a poor prognostic factor. These results suggest that the gene regulatory network of BACH1 and downstream genes including CDH1 contribute to the malignant features of PDAC by regulating epithelial-tomesenchymal transition.Significance: Greater understanding of the gene regulatory network involved in epithelial-to-mesenchymal transition of pancreatic cancer cells will provide novel therapeutic targets and diagnostic markers.

Background: Adenoid cystic carcinoma is a rare malignant tumor arising from exocrine glands such as the major and minor salivary glands of the paranasal sinuses or the external auditory canal. Although multiple retrospective clinical studies of ACC have been reported to date, clinical questions, such as 1) long-term prognosis beyond 20 years, 2) usefulness and suitability for treatment of therapeutic interventions, 3) therapeutic goal to aim for, and 4) prognosis by recurrence sites, are still unclear. Methods: To improve understanding and management of adenoid cystic carcinoma of the head and neck (ACC), a retrospective study with 58 new ACC cases between 1991 and 2016 was performed. The median observation period was 66.8 months (range 3-316 months). The overall clinical stages were as follows: I, 6.9%; II, 25.9%; III, 19.0%; and IV, 48.2%. Histology was cribriform/tubular type (C-T type) in 62.0% and solid type in 27.5%. The main treatment strategy was definitive surgery, which was performed in 75.2% of cases.

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<div>Abstract<p>Pancreatic ductal adenocarcinoma (PDAC) is among the cancers with the poorest prognoses due to its highly malignant features. BTB and CNC homology 1 (BACH1) has been implicated in RAS-driven tumor formation. We focused on the role of BACH1 in PDAC, more than 90% of which have <i>KRAS</i> mutation. Knockdown of BACH1 in PDAC cell lines reduced cell migration and invasion, in part, by increasing E-cadherin expression, whereas its overexpression showed opposite effects. BACH1 directly repressed the expression of <i>FOXA1</i> that is known to activate the expression of <i>CDH1</i> encoding E-cadherin and to inhibit epithelial-to-mesenchymal transition. BACH1 also directly repressed the expression of genes important for epithelial cell adhesion including <i>CLDN3</i> and <i>CLDN4</i>. In a mouse orthotopic implantation model, BACH1 was required for the high metastatic ability of AsPC-1 cells. IHC analysis of clinical specimens with a newly developed anti-BACH1 mAb revealed that high expression of BACH1 is a poor prognostic factor. These results suggest that the gene regulatory network of BACH1 and downstream genes including <i>CDH1</i> contribute to the malignant features of PDAC by regulating epithelial-to-mesenchymal transition.</p>Significance:<p>Greater understanding of the gene regulatory network involved in epithelial-to-mesenchymal transition of pancreatic cancer cells will provide novel therapeutic targets and diagnostic markers.</p></div>