Search

Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), omega-3 polyunsaturated fatty acids (ω-3 PUFAs) derived from fish oil, are widely used as dietary supplements and FDA-approved treatments for hypertriglyceridemia. However, studies investigating the effects of EPA and DHA on colorectal carcinogenesis (CRC) have yielded conflicting results. The factors that determine these discrepant results remain unknown. Resolvins, oxidative metabolites of EPA and DHA, inhibit key pro-tumorigenic cytokine and chemokine signaling of colorectal cancer (e.g., IL-6, IL-1β, and CCL2). 15-lipoxygenase-1 (ALOX15), a critical enzyme for resolvin generation is commonly lost during human CRC. Whether ALOX15 expression, as a host factor, modulates the effects of EPA and DHA on CRC remains unknown. Therefore, we evaluated the effects of ALOX15 transgenic expression in colonic epithelial cells on resolvin generation by EPA and DHA and CRC in mouse models representative of human CRC. Our results revealed that 1) EPA and DHA effects on CRC were diverse, ranging from suppressive to promotive, and these effects were occasionally altered by the formulations of EPA and DHA (free fatty acid, ethyl ester, triglyceride); 2) EPA and DHA uniformly suppressed CRC in the presence of intestinal ALOX15 transgenic expression, which induced the production of resolvins, decreased colonic CCL3-5 and CXCL-5 expression and tumor associated macrophages while increasing CD8 T cell abundance in tumor microenvironment; and 3) RvD5, the predominant resolvin produced by ALOX15, inhibited macrophage generation of pro-tumorigenic cytokines. These findings demonstrate the significance of intestinal ALOX15 expression as a host factor in determining the effects of EPA and DHA on CRC., Significance: Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are widely used as dietary supplements and FDA-approved treatments for hypertriglyceridemia. Studies of EPA and DHA effects on colorectal carcinogenesis (CRC) have revealed inconsistencies; factors determining the direction of their impact on CRC have remained unidentified. Our data show that EPA and DHA effects on CRC were divergent and occasionally influenced by their formulations. More importantly, intestinal 15-lipoxgenase-1 (ALOX15) expression modulated EPA and DHA effects on CRC, leading to their consistent suppression of CRC. ALOX15 promoted EPA and DHA oxidative metabolism to generate resolvins, which inhibited key pro-tumorigenic inflammatory cytokines and chemokines, including IL-6. IL-1β, and CCL2. ALOX15 is therefore an important host factor in determining EPA and DHA effects on CRC.

BACKGROUND Solitary fibrous tumors (SFT), rare soft-tissue neoplasms, are usually found in the thoracic cavity, and a uterine origin is extremely rare. SFTs with insulin-like growth factor-II (IGF-II) production induce non-islet cell tumor-induced hypoglycemia (NICTH), referred to as Doege-Potter syndrome. CASE REPORT A 70-year-old woman presented with urinary retention, and imaging revealed a huge mass occupying almost the entire pelvic space. She had a history of hysterectomy for leiomyoma of the uterus 7 years earlier. In her present course, she developed hypoglycemia, and NICTH was suspected. Her previous uterine specimen was reexamined, and immunohistochemistry (IHC) revealed the specimen to be CD34-positive and alpha-smooth muscle actin-negative, indicating that the uterine specimen was not leiomyoma but SFT. Therefore, the present pelvic tumor was considered to be a recurrence of SFT with NICTH, namely Doege-Potter syndrome. Surgical resection was performed, and the pathological examination showed the same histologic features as the previous uterine specimen, while IHC revealed the present specimen to be positive for CD34, signal transducers and activator of transcription 6, and IGF-II, consistent with the diagnosis of recurrent SFT with IGF-II production. The patient's hypoglycemia improved after tumor resection. To confirm the IGF-II secretion from the SFT, we conducted immunoblotting of the patient's perioperative serum, with results showing that the strong band of IGF-II in the preoperative serum disappeared after surgery. CONCLUSIONS Because SFTs, especially those with Doege-Potter syndrome, often recur, sometimes with a very long interval, long-term cautious surveillance is required, even after complete tumor resection.

APC mutations activate aberrant β-catenin signaling to drive initiation of colorectal cancer; however, colorectal cancer progression requires additional molecular mechanisms. PPAR-delta (PPARD), a downstream target of β-catenin, is upregulated in colorectal cancer. However, promotion of intestinal tumorigenesis following deletion of PPARD in Apc min mice has raised questions about the effects of PPARD on aberrant β-catenin activation and colorectal cancer. In this study, we used mouse models of PPARD overexpression or deletion combined with APC mutation ( Apc Δ580 ) in intestinal epithelial cells (IEC) to elucidate the contributions of PPARD in colorectal cancer. Overexpression or deletion of PPARD in IEC augmented or suppressed β-catenin activation via up- or downregulation of BMP7/TAK1 signaling and strongly promoted or suppressed colorectal cancer, respectively. Depletion of PPARD in human colorectal cancer organoid cells inhibited BMP7/β-catenin signaling and suppressed organoid self-renewal. Treatment with PPARD agonist GW501516 enhanced colorectal cancer tumorigenesis in Apc Δ580 mice, whereas treatment with PPARD antagonist GSK3787 suppressed tumorigenesis. PPARD expression was significantly higher in human colorectal cancer-invasive fronts versus their paired tumor centers and adenomas. Reverse-phase protein microarray and validation studies identified PPARD-mediated upregulation of other proinvasive pathways: connexin 43, PDGFRβ, AKT1, EIF4G1, and CDK1. Our data demonstrate that PPARD strongly potentiates multiple tumorigenic pathways to promote colorectal cancer progression and invasiveness. SIGNIFICANCE: These findings address long-standing, important, and unresolved questions related to the potential role of PPARD in APC mutation-dependent colorectal tumorigenesis by showing PPARD activation enhances APC mutation-dependent tumorigenesis., (©2019 American Association for Cancer Research.)

Mucocele of the appendix due to endometriosis is extremely rare, and there are only 10 previously reported cases in the English literature. We report a case of mucocele of the appendix due to endometriosis and provide the first review of the literature. A 43-year-old woman was admitted to the hospital because of recurrent right lower abdominal pain during her menstrual periods. Colonoscopy revealed submucosal tumor-like elevations of the appendiceal orifice. Computed tomography and magnetic resonance imaging of the abdomen suggested cystic lesions near the appendix. Consequently, mucocele of the appendix was suspected preoperatively. An open ileocecal resection was performed. Multiple cystic lesions were observed around the appendix. The cystic lesions contained mucus. Histopathological examination was consistent with a mucocele of the appendix due to endometriosis. The postoperative course was uneventful. We present the first review of the literature to clarify the clinical features.

We report an extremely rare case of primary pancreatic plasmacytoma. A 56-year-old man had a 4-cm mass in the pancreatic tail and received distal pancreatectomy. This mass mainly consisted of plasma cells, but we failed to demonstrate their monoclonality in spite of the immunohistological staining. One and a half years later, this patient's right inguinal node swelled, and this node also showed a dense plasma cell infiltration. A very precise immunohistological staining was performed for this lymph node and the previous pancreatic mass, and both were diffusely positive for kappa light chain, IgG, and CD38. In the absence of myeloma elsewhere, we thus reached the correct diagnosis of primary pancreatic plasmacytoma, which later metastasized to lymph nodes. In the presence of the plasma cell proliferation in a pancreatic mass, plasmacytoma should be taken into consideration, and a more careful immunohistological staining is definitely necessary.