Prostaglandin E2/EP signaling in the tumor microenvironment of colorectal cancer

This article belongs to the Special Issue Molecular and Translational Research on Colorectal CancerThe number of colorectal cancer (CRC) patients is increasing worldwide. Accumulating evidence has shown that the tumor microenvironment (TME), including macrophages, neutrophils, and fibroblasts, plays an important role in the development and progression of CRC. Although targeting the TME could be a promising therapeutic approach, the mechanisms by which inflammatory cells promote CRC tumorigenesis are not well understood. When inflammation occurs in tissues, prostaglandin E2 (PGE2) is generated from arachidonic acid by the enzyme cyclooxygenase-2 (COX-2). PGE2 regulates multiple functions in various immune cells by binding to the downstream receptors EP1, EP2, EP3, and EP4, and plays an important role in the development of CRC. The current therapies targeting PGE2 using non-steroidal anti-inflammatory drugs (NSAIDs) or COX-2 inhibitors have failed due to the global prostanoid suppression resulting in the severe adverse effects despite the fact they could prevent tumorigenesis. Therefore, therapies targeting the specific downstream molecules of PGE2 signaling could be a promising approach. This review highlights the role of each EP receptor in the TME of CRC tumorigenesis and their therapeutic potential

Transforming growth factor-β signaling pathway in colorectal cancer and its tumor microenvironment

Transforming growth factor-beta (TGF-β) signaling is one of the important cellular pathways that play key roles for tissue maintenance. In particular, it is important in the context of inflammation and tumorigenesis by modulating cell growth, differentiation, apoptosis, and homeostasis. TGF-β receptor type 2 (TGFBR2) mutations affected by a mismatch repair deficiency causes colorectal cancers (CRCs) with microsatellite instability, which is, however, associated with relatively better survival rates. On the other hand, loss of SMAD4, a transcription factor in the TGF-β superfamily signaling, promotes tumor progression. Loss of heterozygosity on chromosome 18 can case SMAD4-deficient CRC, which results in poorer patients’ survival. Such bidirectional phenomenon driven by TGF-β signaling insufficiency reflects the complexity of this signaling pathway in CRC. Moreover, recent understanding of CRC at the molecular level (consensus molecular subtype classification) provides deep insight into the important roles of TGF-β signaling in the tumor microenvironment. Here we focus on the TGF-β signaling in CRC and its interaction with the tumor microenvironment. We summarize the molecular mechanisms of CRC tumorigenesis and progression caused by disruption of TGF-β signaling by cancer epithelial cells and host stromal cells

Fluorescence diagnosis of metastatic lymph nodes using 5-aminolevulinic acid (5-ALA) in a mouse model of colon cancer.

[Background]Lymph node metastasis is one of the most critical prognostic factors in patients with colorectal cancer. Although regional lymph nodes should be surgically resected and pathologically examined, techniques for the intraoperative diagnosis of lymph node metastasis remain to be well established. Fluorescence diagnosis using 5-aminolevulinic acid (5-ALA) is a promising technique for evaluating various malignancies. After exogenous administration of 5-ALA, protoporphyrin IX (PPIX) accumulates in malignant cells and can be detected as red fluorescence. In this study, we investigated the usefulness of fluorescence diagnosis using 5-ALA for the detection of lymph node metastasis in a mouse model of colon cancer. [Materials and Methods]An orthotopic colon cancer model was prepared by inoculating the cecal wall of nude mice with HCA7, a human colon adenocarcinoma cell line. After 3 wk, 40 mg/kg of 5-ALA was administered intraperitoneally (IP) or orally (PO). Fluorescence diagnosis with a D-Light System (Karl Storz) was then performed after 3 or 6 h. [Results]In the IP group, PPIX fluorescence was detected in metastatic lymph nodes as well as in other malignant lesions, including primary tumors and abdominal implantations, while non-metastatic nodes were fluorescence-negative. In contrast, no obvious fluorescence was detected in cancerous tissues in the PO group. [Conclusions]PPIX fluorescence induced by intraperitoneal injection of 5-ALA allows metastatic lymph nodes to be accurately diagnosed in this mouse model. This technique may facilitate the intraoperative diagnosis of lymph node metastases from colon cancer in a clinical setting

Laparoscopy endoscopy cooperative surgery for gastric plexiform fibromyxoma: a case report

[Background] Gastric submucosal tumors are commonly treated by partial resection under laparoscopy. However, the surgical resection of gastric submucosal tumors sometimes causes deformation of the stomach, especially in the case of intraluminal tumors located near the pylorus or esophagogastric junction. Such deformations can result in impaired diet intake and reduced quality of life. Laparoscopic endoscopic cooperative surgery has been developed to overcome these problems. This is the first report to describe a case of gastric plexiform fibromyxoma, a rare gastric submucosal tumor, that was successfully resected by laparoscopic endoscopic cooperative surgery. [Case presentation] A 36-year-old Japanese woman presented with epigastric pain and anemia. Gastrointestinal endoscopy revealed a submucosal tumor in the gastric antrum. Because a definitive diagnosis could not be obtained and the tumor was located near the pylorus, we performed laparoscopic endoscopic cooperative surgery as diagnostic therapy. The postoperative course was favorable with no complications, such as delayed gastric emptying or outlet obstruction. The tumor was pathologically diagnosed as gastric plexiform fibromyxoma. [Conclusions] Laparoscopic endoscopic cooperative surgery is a useful approach for diagnostic therapy for rare submucosal tumors to avoid the deformation of the stomach, especially when the tumor is located near the pylorus

Impact of neoadjuvant chemotherapy on physical fitness, physical activity, and health-related quality of life of patients with resectable esophageal cancer.

Neoadjuvant chemotherapy (NAC) followed by radical surgery is the standard treatment for patients with resectable esophageal squamous cell carcinoma (ESCC) in Japan. However, some adverse events associated with NAC may result in a decrease in physical fitness that may influence the patient's ability to tolerate surgery. The purpose of this study was to evaluate the impact of NAC on physical fitness, physical activity, and health-related quality of life (HRQOL) of patients with ESCC

Hydrodynamic stress stimulates growth of cell clusters via the ANXA1/PI3K/AKT axis in colorectal cancer

Cancer cells are exposed to various stresses in vivo, including hydrodynamic stress (HDS). HDS on cancer cells in the blood stream can influence the metastatic potential. Recent studies revealed that circulating tumor cell clusters are more responsible for metastasis than circulating single cells. Nevertheless, most studies on HDS are based on single cells prepared from established cancer cell lines. Here, we used cancer tissue-originated spheroids (CTOS) as a patient-derived, 3D organoid model to investigate the effect of HDS on cancer cell clusters. We found that HDS induced the growth of cancer cell clusters in a population of colorectal CTOSs. Microarray analyses revealed that the multifunctional protein, Annexin 1 (ANXA1), was upregulated upon HDS exposure. Chemically-induced membrane damage also triggered the expression of ANXA1. A knockdown of ANXA1 revealed that ANXA1 regulated HDS-stimulated growth in colorectal CTOSs. Mechanistically, activating the PI3K/AKT pathway downstream of ANXA1 contributed to the phenotype. These findings demonstrate that HDS induces the growth of cancer cell clusters via ANXA1/PI3K/AKT axis, which helps to elucidate the pro-metastatic feature of circulating cancer cell clusters

Classification of Standard Model Particles in E6E_6 Orbifold Grand Unified Theories

We classify the standard model fermions, which originate from bulk fields of the $\bf{27}$ or $\bar{\bf{27}}$ representation after orbifold breaking, in $E_6$ grand unified theories on 5 or 6-dimensional space-time, under the condition that $q$, $e^c$ and $u^c$ survive as zero modes.Comment: 24 pages, typos corrected, to appear in IJMP

Preoperative chemoradiotherapy for locally advanced low rectal cancer using intensity-modulated radiotherapy to spare the intestines: a single-institutional pilot trial

The irradiated volume of intestines is associated with gastrointestinal toxicity in preoperative chemoradiotherapy for rectal cancer. The current trial prospectively explored how much of the irradiated volume of intestines was reduced by intensity-modulated radiotherapy (IMRT) compared with 3-dimensional conformal radiotherapy (3DCRT) and whether IMRT might alleviate the acute gastrointestinal toxicity in this population. The treatment protocol encompassed preoperative chemoradiotherapy using IMRT plus surgery for patients with clinical T3–4, N0–2 low rectal cancer. IMRT delivered 45 Gy per 25 fractions for gross tumors, mesorectal and lateral lymph nodal regions, and tried to reduce the volume of intestines receiving 15 Gy (V₁₅ Gy) < 120 cc and V₄₅ Gy ≤ 0 cc, respectively, while keeping target coverage. S-1 and irinotecan were concurrently administered. Acute gastrointestinal toxicity, rates of clinical downstaging, sphincter preservation, local regional control (LRC) and overall survival (OS) were evaluated. Twelve enrolled patients completed the chemoradiotherapy protocol. The volumes of intestines receiving medium to high doses were reduced by the current IMRT protocol compared to 3DCRT; however, the predefined constraint of V15 Gy was met only in three patients. The rate of ≥ grade 2 gastrointestinal toxicity excluding anorectal symptoms was 17%. The rates of clinical downstaging, sphincter preservation, three-year LRC and OS were 75%, 92%, 92% and 92%, respectively. In conclusion, preoperative chemoradiotherapy using IMRT for this population might alleviate acute gastrointestinal toxicity, achieving high LRC and sphincter preservation; although further advancement is required to reduce the irradiated volume of intestines, especially those receiving low doses

Prevalence and safety of robotic surgery for gastrointestinal malignant tumors in Japan

[Aim] The National Health Insurance system has reimbursed robotic gastrointestinal surgery since April 2018 in Japan. Additionally, strict facility and surgeon standards were established by the government and the academic society. This study aimed to evaluate the prevalence and safety of robotic surgery using a Japanese nationwide web-based database. [Methods] Patients who underwent the following robotic surgeries for malignant tumors in 2018 were included: esophagectomy (RE), total gastrectomy (RTG), distal gastrectomy (RDG), proximal gastrectomy (RPG), low anterior resection (RLAR), and rectal resections other than RLAR (RRR). The number of cases and surgical mortality rates each month were calculated to evaluate the prevalence and safety of robotic procedures. [Results] A total of 3281 patients underwent robotic gastrointestinal surgery. The monthly number of robotic surgeries nearly doubled in April 2018 when they were initially reimbursed by the National Health Insurance system. Operative mortality rates were 0.9%, 0.4%, 0.2%, and 2.8% for RE (n = 330), RTG (n = 239), RDG (n = 1167), and RPG (n = 109), respectively. No mortality was observed in RLAR (n = 1062) or RRR (n = 374). [Conclusion] Robotic surgery for gastrointestinal malignant tumors was safely introduced into daily clinical practice along with rigorous surgeon and facility standards in Japan