Ultrastructure of interstitial cells of Cajal in myenteric plexus of human colon

The role of the interstitial cells of Cajal (ICC) associated with the myenteric plexus (ICC-MP) as regulators of the motility of the colonic external muscle remains unclear. Ultrastructural studies of myenteric interstitial cells are lacking in human colon. We therefore characterized the distinctive ultrastructure of these cells in the myenteric region of the colon by transmission electron microscopy of the region between the main muscle layers in all parts of the colon in unaffected areas of resected specimens from nine adult human patients. ICC-MP were similar in various colonic regions and had myoid features such as scattered caveolae, prominent intermediate filaments, and cytoplasmic dense bodies. We found characteristic dense membrane-associated bands with a patchy basal lamina, invaginating cellular protrusions (peg and socket junctions) between ICC and between ICC and muscle cells, and close contacts (<100 nm) between ICC and nerves. No gap junctions were observed. Fibroblast-like cells (FLC) were abundant showing well-developed secretory organelles, including coated vesicles, but lacked prominent intermediate filaments and caveolae. FLC had a patchy basal lamina, and peg and socket junctions were observed between them. Macrophage-like cells frequently occurred in close apposition with FLC and, more seldomly, with ICC-MP. The ultrastructure of ICC and FLC in the myenteric region of the human colon thus differs characteristically, but significant overlaps in the ultrastructure between ICC and FLC might complicate any interpretation in pathological ultrastructural studies of the human colonic muscle layer. An erratum to this article can be found at     

Identification of Glucagon Receptors in Rat Retina

In this study, we characterize the glucagon receptors on rat retinal particulate preparations. The specific binding of 125I-glucagon was saturable and reversible. Apparent equilibrium conditions were established within 30-45 min. Analysis of binding data is compatible with the existence of two classes of binding sites: a high-affinity class with a KD of 7 +/- 0.8 nM and a Bmax of 2.3 +/- 0.2 pmol/mg of protein and a low-affinity class with a KD of 84.4 +/- 2.5 nM and a Bmax of 16.5 +/- 2.3 pmol/mg of protein. The 125I-glucagon binding to retinal particulate preparation was not inhibited by 1 microM concentrations of insulin, atrial natriuretic factor, angiotensin II, somatostatin, and vasoactive intestinal peptide. However, synthetic human pancreatic growth hormone-releasing factor, hGRF-44, inhibited binding, although the concentration required for half-maximal displacement was 10-fold higher than that for native glucagon. Glucagon binding was GTP sensitive. Inclusion of 0.1 mM GTP in the binding assay produced an increase in the concentration of unlabeled glucagon required for half-maximal displacement of 125I-glucagon, from 23 to 220 nM. Glucagon stimulated adenylate cyclase formation in retinal particulate preparations. The concentration of glucagon required for half-maximal activation of retinal adenylate cyclase was 16.2 nM. These results suggest that glucagon may play a role as a neurosignal transmitter in rat retina.     

Ontogeny of immunoreactive glicentin in the human gastrointestinal tract and endocrine pancreas

The gestational time of appearance and distribution of immunoreactive glicentin was compared to that of immunoreactive glucagon in the gastrointestinal tract and endocrine pancreas of human fetuses, aged between 5 and 24 weeks, by an indirect immunoperoxidase method. With the glicentin antiserum No. R 64, the first immunoreactive cells were detected at the 10th week of gestation in the oxyntic mucosa and proximal small intestine, at the 8th week in the ileum and at the 12th week in the colon. In the endocrine pancreas, the first immunoreactive cells were observed as early as 8 weeks within the walls of the primitive pancreatic ductules. At a more advanced stage of development (12 weeks), they were found interspersed among the islet cell clusters and still later (16 weeks) inside the recognizable islets of Langerhans. With the glucagon antiserum No. GB 5667, no immunoreactive cells were demonstrated in the gastrointestinal tract whatever the age of the fetuses. In the endocrine pancreas, the first immunoreactive cells were observed at the 8th week of gestation in the pancreatic parenchyma. The distribution of glucagon-containing cells in the pancreas was similar to that of glicentin immunoreactivity throughout ontogenesis. In the pancreatic islets of one 18-week-old human fetus, the study of consecutive semithin sections treated by both antisera showed that the same cells were labelled. The significance of these findings concerning the role of glicentin as a glucagon precursor is discussed.     

Sustentacular cells in the fetal human adrenal medulla are immunoreactive with antibodies to brain S-100 protein

Summary Adrenal glands of human fetuses were investigated by means of an immunohistochemical method with the use of an anti-S-100 serum. S-100-immunoreactivity was recognized in sustentacular cells located among the chromaffin cells. A characteristic circular arrangement of the immunostained cells was found in the central region of the adrenal glands. It surrounded aggregations of non-argyrophilic, small, round cells, which were identified as the remaining sympathoblasts (primitive sympathetic cells).     

Ubiquitin ligase A20 regulates p53 protein in human colon epithelial cells

Background

Intestinal polyps may further develop into colon cancer; the pathogenesis is not clear. The p53 gene is an important anti-cancer gene in the body, which is suppressed in cancer. The ubiquitin E3 ligase A20 (A20) plays a role in regulating the activities of epithelial cells. This study was designed to investigate the role of the colon polyp epithelium-derived A20 in the pathogenesis of colon cancer.

Results

Eighty-eight colon cancer patients and 136 colon polyp patients were recruited into this study. Human colon cancer tissue, the epithelium of adenomas polyp and hyperplastic polyp showed high levels of A20, which had a positive correlation with the cancerous tendency of colon polyps. The levels of A20 were much higher in the adenomas and hyperplastic polyps than that in the inflammatory polyps; the latter showed less cancerous tendency. A20 bound p53 to form complexes in colon cancer tissue and colon polyps. Over expression of A20 suppresses P53 protein levels in the HEK293 cells.

Conclusions

A20 may play an important role in the cancerous tendency of colon polyposis.     

结肠腺癌组织中COX-2和PTEN蛋白表达与临床病理特征的相关性分析

目的检测环氧合酶-2（COX-2）和PTEN蛋白在结肠癌中的表达,探讨两基因表达与临床病理因素的关系以及二者之间的关系。方法选择2010年1月-2012年4月在我校附属医院行根治手术切除的结肠腺癌组织56例,另取同期活检15例非肿瘤结肠黏膜组织作为对照,采用免疫组织化学方法检测COX-2和PTEN蛋白的表达情况。结果COX-2在结肠腺癌组织中阳性率高于非肿瘤结肠黏膜组织（82．1% vs 13．3％,P〈0．05）;PTEN在结肠腺癌组织中阳性率低于非肿瘤结肠黏膜组织（51．8％vs 100．0％,P〈0．05）。COX-2与PTEN的表达与Duke分期及有无淋巴结转移有关,而与性别、年龄和组织学分型无明显相关。结肠腺癌组织中COX-2和PTEN的表达呈负相关（r=-0．357,P=0．007）。结论COX-2表达上调及PTEN失表达与结肠腺癌的发生发展、浸润、转移有关,两指标联合检测有助于结肠腺癌生物学行为的评估。     

O-GlcNAcylation is a novel regulator of lung and colon cancer malignancy

O-GlcNAc is a monosaccharide attached to serine or threonine hydroxyl moieties on numerous nuclear and cytoplasmic proteins; O-GlcNAcylation is dynamically regulated by O-GlcNAc transferase (OGT) and O-GlcNAcase (OGA). Although recent studies have shown that O-GlcNAcylation plays essential roles in breast cancer progression, it is also necessary to know whether O-GlcNAcylation is involved in other types of human cancer. In this study, O-GlcNAcylation levels and the expressions of OGT and OGA in human lung and colon cancer tissues were examined by immunohistochemistry analysis. We found that O-GlcNAcylation as well as OGT expression was significantly elevated in the cancer tissues compared with that in the corresponding adjacent tissues. Additionally, the roles of O-GlcNAcylation in the malignancy of lung and colon cancer were investigated in vitro. The results showed that O-GlcNAcylation markedly enhanced the anchorage-independent growth of lung and colon cancer cells; O-GlcNAcylation could also enhance lung and colon cancer invasion in a context-dependent manner. All together, this study suggests that O-GlcNAcylation might play important roles in lung and colon cancer formation and progression, and may be a valuable target for diagnosis and therapy of cancer.     

Combined dual effect of modulation of human neutrophils’ oxidative burst and inhibition of colon cancer cells proliferation by hydroxycinnamic acid derivatives

Colon cancer is one of the most incident cancers in the Western World. While both genetic and epigenetic factors may contribute to the development of colon cancer, it is known that chronic inflammation associated to excessive production of reactive oxygen and nitrogen species by phagocytes may ultimately initiate the multistep process of colon cancer development. Phenolic compounds, which reveal antioxidant and antiproliferative activities in colon cancer cells, can be a good approach to surpass this problem. In this work, hydroxycinnamic amides and the respective acid precursors were tested in vitro for their capacity to modulate human neutrophils’ oxidative burst and simultaneously to inhibit growth of colon cancer cells. A phenolic amide derivative, caffeic acid hexylamide (CAHA) (4) was found to be the most active compound in both assays, inhibiting human neutrophils’ oxidative burst, restraining the inflammatory process, inhibiting growth of colon cancer cells and triggering mitochondrial dysfunction that leads cancer cells to apoptosis. Altogether, these achievements can contribute to the understanding of the relationship between antioxidant and anticancer activities and based on the structure–activity relationships (SAR) established can be the starting point to find more effective phenolic compounds as anticancer agents.     

2 型糖尿病患者胰高血糖素及胰岛素水平检测及临床意义

目的:探讨2型糖尿病患者经标准馒头餐试验后胰高血糖素、胰岛素水平变化及其临床意义。方法:选取我院2014年3月至2015年3月收治的80例2型糖尿病患者为试验组,均接受标准馒头餐试验,对其餐前及餐后0.5 h、1 h、2 h胰高血糖素及胰岛素水平进行检测,并与同期80例血糖无异常的健康对照组作比较。结果:健康对照组餐前及餐后胰高血糖素水平无明显变化(P0.05),而试验组餐前胰高血糖素水平明显高于健康对照组(P0.05),且餐后明显升高,在餐后1 h达到峰值,餐后0.5 h、1h、2 h均明显高于健康对照组(P0.01)。健康对照组餐后胰岛素水平明显升高,在餐后1 h达到峰值后开始降低,较餐前略高,但差异平无统计学意义(P0.05);试验组餐前胰岛素水平明显低于健康对照组(P0.05),且餐后水平升高幅度缓慢,餐后0.5 h、1 h、2h均明显低于健康对照组(P0.05);实验组胰岛素抵抗指数(HOMA-IR)明显高于健康对照组,经Pearson相关分析,试验组餐后0.5 h、1 h、2 h胰高血糖素水平与HOMA-IR均呈明显的正相关(r=0.273、0.335、0.368,P0.05)。结论:2型糖尿病患者血糖高表达与胰高血糖素、胰岛素水平密切相关,胰高血糖素可拮抗胰岛素,及时检测二者的水平对临床准确评估病情具有重要的意义。     

Projections of 5-hydroxytryptamine-immunoreactive neurons in guinea-pig distal colon

The presence of 5-hydroxytryptamine in enteric neurons of the guinea-pig distal colon was demonstrated by immunohistochemistry and the projections of the neurons were determined. 5-Hydroxytryptamine-containing nerve cells were observed in the myenteric plexus but no reactive nerve cells were found in submucous ganglia. Varicose reactive nerve fibres were numerous in the ganglia of both the myenteric and submucous plexuses, but were infrequent in the longitudinal muscle, circular muscle, muscularis mucosae and mucosa. Reactivity also occurred in enterochromaffin cells. Lesion studies showed that the axons of myenteric neurons projected anally to provide innervation to the circular muscle and submucosa and to other more anally located myenteric ganglia. The results suggest that a major population of 5-hydroxytryptamine neurons in the colon is descending interneurons, most of which extend for 10 to 15 mm in the myenteric plexus and innervate both 5-hydroxytryptamine and non-5-hydroxytryptamine neurons.     

Ontogeny and distribution of certain endocrine cells in the human fetal large intestine

Summary In 9 fetuses, 9 to 24 weeks-old, the occurrence and relative distribution of argentaffin cells, as well as of cells immunoreactive to somatostatin (SRIF), glucagon-like polypeptide (GLI), pancreatic polypeptide (PP) and substance P (SP) were studied in five segments of the colon (appendix, cecum, ascending colon, descending colon, and rectosigmoid). For each colonic segment, data concerned with the occurrence of endocrine cells were expressed either as mean absolute numbers of specific cells per entire mucosal section, or as cell densities per mm³ of mucosa after calculation of the mucosal volume of the sections. Argentaffin, GLI, SRIF and PP immunoreactive cells are all present in relatively large numbers, scattered along the entire length of the colonic mucosa as early as the 9th–10th week of gestation, whereas substance P-containing cells occur sporadically and first appear during the 14th–17th week. Until the 20th week, with progressing embryonic development, an increase was determined in absolute numbers per section of all types of endocrine cells in all segments of the colon. This observation is clearly related to the general growth of the colonic mucosa, since cell densities per mm³ of mucosa do not greatly change or even decrease during gestation. However, it is possible that densities of argentaffin, GLI and BPP cells increase in the appendix around the 14th–17th week of gestation. Between the 20th and 24th week, absolute numbers of cells per section remain stable or slightly increase, while cell densities tend rather to decrease in all segments. These data demonstrate that some endocrine cells are present very early in the human fetal colon, but their functional significance remains to be elucidated.This work was supported by the Institut National de la Santé et de la Recherche Médicale (INSERM)     

A novel histone deacetylase inhibitor Chidamide induces apoptosis of human colon cancer cells

Many studies have demonstrated that histone deacetylase (HDAC) inhibitors induce various tumor cells to undergo apoptosis, and such inhibitors have been used in different clinical trials against different human cancers. In this study, we designed and synthesized a novel HDAC inhibitor, Chidamide. We showed that Chidamide was able to increase the acetylation levels of histone H3 and to inhibit the PI3K/Akt and MAPK/Ras signaling pathways, which resulted in arresting colon cancer cells at the G1 phase of the cell cycle and promoting apoptosis. As a result, the proliferation of colon cancer cells was suppressed in vitro. Our data support the potential application of Chidamide as an anticancer agent in treating colon cancer. Future studies are needed to demonstrate its in vivo efficacy.     

Quinone-induced apoptosis in human colon adenocarcinoma cells via DT-diaphorase mediated bioactivation

DT-diaphorase (DTD) activity has been related to bioactivation and cytotoxicity of antitumor quinones. A pair of human colon adenocarcinoma cell lines, HT29 and BE, were used in this study to examine the role of DTD in antitumor quinone induced apoptosis. HT29 cells have elevated levels of DTD whereas BE cells lack functional DTD due to a point mutation which results in a complete lack of DTD activity. MeDZQ, a quinone that is efficiently bioactivated by DTD, induced apoptosis both in HT29 and BE cells, but with a much higher incidence in HT29, as assessed by morphological criteria and the formation of oligonucleosomal fragments of DNA. Two other quinone compounds which are also substrates for DTD, i.e. streptonigrin and mitomycin C, also preferentially induced apoptosis in HT29 cells, which could be inhibited by dicoumarol. Our data suggest that bioreductive activation of antitumor quinones by DTD results in induction of apoptosis in human colon carcinoma cells.     

Alpha-tocopheryl succinate sensitizes human colon cancer cells to exisulind-induced apoptosis

Sulindac sulfone (also known as exisulind) and its chemical derivatives are promising anticancer agents capable of inducing apoptosis in a variety of malignant cell types with minimal toxicity to normal cells. Here, we tested the ability of alpha-tocopheryl succinate (TOS), another promising anticancer agent, to sensitize colon cancer cells to exisulind-induced apoptosis. We found that sub-apoptotic doses of TOS greatly enhanced exisulind-induced growth suppression and apoptosis in the HCT116, LoVo and SNU-C4 human colon cancer cell lines. Our results revealed that this was accounted for primarily by an augmented cleavage of poly(ADP-ribose) polymerase (PARP) and enhanced activation of caspase-8, -9 and -3. Pretreatment with z-VAD-FMK (a pan-caspase inhibitor), z-IETD-FMK (a caspase-8 inhibitor) or z-LEHD-FMK (a caspase-9 inhibitor) blocked TOS and exisulind cotreatment-induced PARP cleavage and apoptosis. Furthermore, TOS/exisulind cotreatment induced JNK phosphorylation, while pretreatment with SP600151 (a JNK inhibitor) partially blocked cotreatment-induced caspase-dependent PARP cleavage and apoptosis. Taken together, these findings indicate that TOS sensitizes human colon cancer cells to exisulind-induced apoptosis. Apoptotic synergy induced by exisulind plus TOS seems likely to be mediated through a mechanism involving activation of caspases and JNK. S.-J. Lim, Y.-J. Lee both authors are contributed equally to this study.     

NSAIDs activate PTEN and other phosphatases in human colon cancer cells: novel mechanism for chemopreventive action of NSAIDs

Studies on chemoprevention of colorectal cancer have generated increasing interest. The mechanisms involved in NSAIDs chemopreventive action are not fully elucidated. In this study, we examined in human colon cancer cells the effect of indomethacin and NS-398 (a pre-clinical selective COX-2 inhibitor) on expression of 96 genes of the EGF/PDGF signaling pathways essential for cell proliferation, migration, and survival. We found that indomethacin and NS-398 treatment significantly upregulated expression of the tumor suppressor gene, PTEN, the MAP kinase phosphatase-3, MKP-3, and the protein tyrosine phosphatase, SHP2. Additionally, NS-398 treatment increased expression of apoptotic genes such as BAD, STAT1, and CASP3. These results suggest that as a consequence of increased expression of phosphatases such as PTEN and the resulting dephosphorylation of kinases, NSAIDs can negatively regulate the EGF/PDGF pathways in colon cancer cells-a novel mechanism for NSAIDs' chemopreventive actions.     

Presence of immunoreactive adrenomedullin in human and bovine milk

We examined by radioimmunoassay the presence of immunoreactive adrenomedullin (ir-AM) in human and bovine milk. Milk samples displaced ¹²⁵I-AM from the AM-antiserum in parallel to the standard curve. RP-HPLC revealed a main immunoreactive peak eluting as synthetic AM. Concentrations in human milk ranged between 140 and 404 pg/mL. In cow, the levels of AM were 73.5 ± 3.8 pg/mL. Bovine milk products had AM levels similar to those found in fresh bovine milk. Human milk had growth promoting activity on the human intestinal cell line Int-407 that could be partially blocked with an anti-AM antibody.