Silencing of PTGS2 exerts promoting effects on angiogenesis endothelial progenitor cells in mice with ischemic stroke via repression of the NF-κB signaling pathway

The objective of the current study is to investigate the effect of PTGS2 on proliferation, migration, angiogenesis and apoptosis of endothelial progenitor cells (EPCs) in mice with ischemic stroke through the NF-κB signaling pathway. Middle cerebral artery occlusion (MCAO) model was established in mice. EPCs were identified, in which ectopic expression and depletion experiments were conducted. The mRNA and protein expression of related factors in tissues and cells were measured. Besides, proliferation, migration, angiogenesis, and apoptosis, as well as cell cycle distribution, of cells were determined. MCAO mice showed overexpression of interleukin-6 (IL-6), IL-17, and IL-23, and increased positive protein expression of PTGS2, as well as expression of PTGS2, nuclear factor-κB (NF-κB), tumor suppressor region 1 (TSP-1) and Bcl-2-associated X protein (Bax), but underexpression of vascular endothelial growth factor (VEGF), S-phase kinase associated protein 2 (Skp2), and B-cell lymphoma 2 (Bcl-2). Moreover, ectopic expression of tumor necrosis factor-α significantly elevated the expression of PTGS2, NF-κB, TSP-1, and Bax, as well as cell apoptosis and cell cycle arrest, but decreased the expression of VEGF, Skp2, and Bcl-2, as well as proliferation, migration and angiogenesis of EPCs, and the PTGS2-siRNA group showed an opposite trend. Taken together, we conclude that the specific knockdown of PTGS2 expression could repress the NF-κB signaling pathway, thereby inhibits apoptosis and promotes proliferation, migration and angiogenesis of EPCs, providing protective effect on mice with ischemic stroke.     

福安泰-03对人脐静脉内皮细胞凋亡和小鼠创伤愈合的影响

研究福安泰-03（Fuantai,FAT-03）对人脐静脉血管内皮细胞（humanumbilicalveinen－dothelialcells,HUVECs）凋亡和小鼠创伤愈合的影响。MTT法检查FAT-03对HUVECs和人低分化鼻咽癌细胞（CNE－2Z）生长的影响：聚碳酸酯膜小室趋化运动模型（Transwellmodel）检测,]FAT-03对HU-VECs运动能力的影响;荧光显微镜观察FAT-03作用下HUVECs的形态变化;膜联蛋白V-异硫氰酸荧光素（AnnexinV-fluoresceinisothiocyanate,AnnexinV-FITC）双染检测Ⅳm03对HUVECs早期凋亡的影响;流式细胞术分析FAT-03对HUVECs周期及凋亡的影响;Westernblot法分析FAT-03对HUVECs的血管内皮细胞生长因子（VEGF）、Bcl．2、Bax表达的影响;小鼠背部创伤模型检查FAT-03对组织修复的影响;免疫组化法检查FAT-03对创伤组织微血管密度（microvesseldensity,MVD）和VEGF表达的影响。结果显示,FAT-03明显抑制HUVECs细胞的增殖和迁移,其抑制效果与剂量和作用时间相关,作用HUVECs24,48,72h的Ic50值为0．22,0．17,0．09mg／mL,但FAT-03对CNE．2Z细胞的生长却无明显的影响;0．16mg／mLFAT-03作用HUVECs24h对细胞迁移的抑制率为57．9％（P＜0．01）：FAT_03处理HUVECs48h,细胞的早期凋亡率增加（P〈0．05）;FAT-03阻滞HUVECs于G0／Gl期,并呈现典型的凋亡峰;0．16mg／mLFAT-03作用48,72h,HUVECs的凋亡率分别为14．6％、41．7％：鲋m03下调HUVECs的VEGF和抑凋亡基因Bcl-2的表达,上调促凋亡基因Bax的表达,其效果与剂量相关。FAT-03明显延迟小鼠创伤的愈合,且其作用与剂量相关。FAT-03组小鼠创伤周围组织微血管密度和VEGF阳性表达细胞都明显减少。因此,可以推测,FAT-03抑制HUVECs增殖并诱导其凋亡;抑制创伤组织的血管生成,进而延迟创伤愈合;它的这些作用可能与其下调VEGF、Bcl-2的表达,上调Bax的表达相关。     

lncRNA RPL34-AS1 inhibits cell proliferation and invasion while promoting apoptosis by competitively binding miR-3663-3p/RGS4 in papillary thyroid cancer

Papillary thyroid cancer (PTC) accounts for 80% of all thyroid cancers and seriously impacts the quality of people's lives. Long noncoding RNAs (lncRNAs) play an important role in PTC. In previous studies, thousands of lncRNAs were screened to study their potential relationships with PTC. The aim of this study was to investigate the effect of RPL34-AS1 in PTC and to explore its potential mechanisms. Bioinformatic analyses were performed to characterize the possible function and biological features of RPL34-AS1. Apoptosis, proliferation, and invasion were detected to assess the effect of RPL34-AS1. Cell proliferation was measured using a Cell Counting Kit-8 assay. Western blot analysis was used to assess the apoptosis proteins Bax and Bcl-2. Cell invasion was measured using a Transwell assay. Quantitative real-time polymerase chain reaction (qRT-PCR) analysis was performed to examine RPL34-AS1, miR-3663-3P, and RGS4 expression. Dual-luciferase assay was performed to assess the binding of miR-3663-3P by RPL34-AS1. RIP experiment was used to verify the combination between miR-3663-3p and RGS4. We found that overexpression of RPL34-AS1 could inhibit proliferation and invasion while promoting apoptosis in PTC cell lines. Moreover, RPL34-AS1 could also competitively bind miR-3663-3p and exert its function by regulating the miR-3663-3p/RGS4 in PTC cell lines. We found a previously uncharacterized lncRNA, RPL34-AS1, and studied its function and mechanism in PTC. Our research will provide new insights into PTC and new clues for its clinical treatment.     

VEGF-E activates endothelial nitric oxide synthase to induce angiogenesis via cGMP and PKG-independent pathways

Vascular endothelial growth factor-A (VEGF), which binds to both VEGF receptor-1 (Flt1) and VEGFR-2 (KDR/Flk-1), requires nitric oxide (NO) to induce angiogenesis in a cGMP-dependent manner. Here we show that VEGF-E, a VEGFR-2-selective ligand stimulates NO release and tube formation in human umbilical vein endothelial cells (HUVEC). Inhibition of phospholipase Cgamma (PLCgamma) with U73122 abrogated VEGF-E induced endothelial cell migration, tube formation and NO release. Inhibition of endothelial nitric oxide synthase (eNOS) using l-NNA blocked VEGF-E-induced NO release and angiogenesis. Pre-incubation of HUVEC with the soluble guanylate cyclase inhibitor, ODQ, or the protein kinase G (PKG) inhibitor, KT-5823, had no effect on angiogenesis suggesting that the action of VEGF-E is cGMP-independent. Our data provide the first demonstration that VEGFR-2-mediated NO signaling and subsequent angiogenesis is through a mechanism that is dependent on PLCgamma but independent of cGMP and PKG.     

急性白血病患者骨髓组织血管新生与Bcl-2蛋白关系的研究

目的：探讨急性白血病患者骨髓组织血管新生与Bcl-2蛋白的关系,为临床治疗白血病提供可靠的理论依据。方法：回顾性分析2007年3月～2011月6月我院收治的42例急性白血病患者和42例增生性贫血和疑为血液系统疾病的患者作为对照组的临床资料。结果：对照组患者骨髓组织中的微血管密度（MVD）、血管内皮生长因子（VEGF）及Bcl-2蛋白的表达水平均显著低于急性白血病患者,两组比较差异有极显著统计学意义（P〈0.01）。急性白血病患者骨髓组织中VEGF、MVD及Bcl-2蛋白之间,彼此两两呈正相关性。结论：Bcl-2蛋白的阳性表达在白血病的抗凋亡与血管新生方面,都发挥着重要的作用,通过对Bcl-2蛋白的研究,为临床治疗白血病提供了一条诊断、治疗白血病的新思路。     

Silencing of long noncoding RNA LEF1-AS1 prevents the progression of hepatocellular carcinoma via the crosstalk with microRNA-136-5p/WNK1

Long noncoding RNAs (lncRNAs) have been recognized as cancer-associated biological molecules, favoring hepatocellular carcinoma (HCC) progression. This study was conducted to elucidate the effects lncRNA lymphoid enhancer-binding Factor 1 antisense RNA (LEF1-AS1) on the pathological development of HCC, along with the crosstalk involving microRNA-136-5p (miR-136-5p) and with-no-K (lysine) kinase 1 (WNK1). The study recruited primary HCC tissues and their corresponding nonneoplastic liver tissues. The gain- and loss-of-function studies were performed in HCC cells HuH-7 and tumor xenografts in nude mice. The dual luciferase reporter gene assay system, RNA pull-down, and radioimmunoprecipitation assays were applied to detect their interactions among lncRNA LEF1-AS1, miR-136-5p, and WNK1. 5-Ethynyl-2′-deoxyuridine staining, scratch test, Transwell assays, and in vitro tube formation assays were conducted to examine HCC cell proliferation, migration, and invasion and HUVEC angiogenesis. HCC tissues and cells contained high lncRNA LEF1-AS1 expression. LncRNA LEF1-AS1 upregulation triggered markedly increased HCC cell proliferation, migration, and invasion and human umbilical vein endothelial cell angiogenesis. In vivo silencing lncRNA LEF1-AS1 resulted in reduced tumor cell vitality and matrix metalloproteinase-9 and the vascular endothelial growth factor expression. Additionally, the role of lncRNA LEF1-AS1 was found to be largely dependent on WNK1. Association of lncRNA LEF1-AS1 with WNK1 blocked the inhibitory effect of miR-136-5p on WNK1, which was confirmed by in vivo experiments. Altogether, our results revealed an important role of lncRNA LEF1-AS1 in regulating the HCC progression by regulating WNK1, providing a potential biomarker for the therapeutic modalities regarding HCC.     

The effect of obestatin on porcine ovarian granulosa cells

The aim of our in vitro experiments was to investigate the role of obestatin, a newly discovered metabolic hormone produced in the stomach and other tissues, in the direct control of ovarian cell proliferation, apoptosis and secretion. Porcine granulosa cells were cultured in the presence of obestatin (0, 1, 10 and 100ng/ml medium). The expression of intracellular peptides associated with proliferation (PCNA, cyclin B1, MAP kinase), as well as markers of apoptosis (Bax, p53, Caspase 3), were detected using immunocytochemistry and Western immunoblotting. Secretion of progesterone (P(4)), testosterone (T) and estradiol (E(2)) was measured by EIA. Addition of obestatin (1-100ng/ml) to the culture medium significantly stimulated the expression of PCNA and resulted in an increase in expression of cyclin B1 and MAPK. It also significantly increased the percentage of cells containing the apoptotic and anti-proliferating peptides p53, Caspase 3 and Bax. At 10 and 100ng/ml, obestatin promoted the secretion of P(4), but not T or E(2). Our results are the first demonstration that obestatin directly controls porcine ovarian cell functions: it can stimulate proliferation (accumulation of rPCNA, cyclin B1 and MAPK), apoptosis (expression of p53, Caspase 3 and Bax) and the secretion of progesterone.     

VEGF和PCNA在骨肉瘤组织中的表达及其临床意义

目的:探讨血管内皮生长因子(VEGF)和增殖细胞核抗原(PCNA)在骨肉瘤组织中的表达及其与微血管密度(MVD)、预后的关系。方法:用免疫组织化学法检测64例骨肉瘤组织中VEGF、PCNA的表达和MVD。结果:VEGF阳性表达主要在胞浆,PCNA的阳性表达主要在胞核。VEGF、PCNA表达与MVD存在显著关联(P<0.05),与骨肉瘤转移和5年生存率有显著关联性(P<0.05)。VEGF表达与PCNA表达密切相关(P<0.05)。结论:VEGF和PCNA指标可作为判断骨肉瘤预后的重要指标。     

Long noncoding MAGI2-AS3 promotes colorectal cancer progression through regulating miR-3163/TMEM106B axis

Colorectal cancer (CRC), is mostly derived from normal colon epithelial cells, and has been reported to be one of most common gastrointestinal malignancies globally. An increasing number of researchers have claimed that long noncoding RNAs (lncRNAs) exert significant functions in tumor progression. Nevertheless, the function of MAGI2-AS3 remains uncertain in CRC. The expression of MAGI2-AS3, miR-3163, and transmembrane protein 106B (TMEM106B) messenger RNA was examined by quantitative real-time polymerase chain reaction. Cell apoptosis was measured by caspase-3 activity test. Cell proliferation was tested by cell-counting kit 8 and 5-ethynyl-2′-deoxyuridine assays. Cell migration was detected by transwell assay. Western blot analysis examined the protein expression of TMEM106B. The expression of Ki-67 was evaluated by immunohistochemistry assay. The binding capacity between miR-3163 and MAGI2-AS3 (or TMEM106B) was studied by radioimmunoprecipitation and luciferase reporter assays. The expression of MAGI2-AS3 and TMEM106B was conspicuously upregulated whereas miR-3163 presented lower expression in CRC cells. MAGI2-AS3 deficiency facilitated cell apoptosis but hampered cell proliferation and migration. MAGI2-AS3 combined with miR-3163 and negatively regulated miR-3163 expression. In addition, the administration of sh-MAGI2-AS3 or miR-3163 mimics suppressed CRC cell growth in vivo. Subsequently, miR-3163 targeted TMEM106B and the transfection of sh-MAGI2-AS3 or miR-3163 mimics downregulated TMEM106B expression. Rescue assays verified that TMEM106B overexpression recovered the effects of MAGI2-AS3 inhibition on cell apoptosis, proliferation, and migration in CRC. MAGI2-AS3 drives CRC progression through regulating miR-3163/TMEM106B axis. This supplies innovative insights on the investigation of molecular mechanism in CRC progression.     

lncRNA RPL34-AS1通过靶向调控miR-575表达对卵巢癌SKOV3细胞增殖和凋亡的影响

目的探究RPL34-AS1对卵巢癌细胞增殖、迁移的影响及其作用机制。 方法取对数生长期SKOV3细胞用无血清培养基同步化12 h,将pcDNA、pcDNA-RPL34-AS1、si-NC、si-RPL34-AS1、anti-miR-NC、anti-miR-575转染至SKOV3细胞中,分别记为pcDNA组、pcDNA-RPL34-AS1组、si-NC组、si-RPL34-AS1组、anti-miR-NC组、anti-miR-575组;将pcDNA-RPL34-AS1与miR-NC、miR-575分别共转染至SKOV3细胞中,记为pcDNA-RPL34-AS1+miR-NC组、pcDNA-RPL34-AS1+miR-575组。实时荧光定量PCR （RT-qPCR）检测临床组织标本及转染后各组细胞中RPL34-AS1和miR-575的表达水平;双荧光素酶报告实验检测RPL34-AS1和miR-575的靶向关系;四甲基偶氮唑盐比色法（MTT）检测细胞存活率;流式细胞术检测细胞凋亡;蛋白质印迹（Western blot）法检测细胞周期蛋白D1（Cyclin D1）、细胞周期蛋白依赖性激酶抑制剂1A （p21）、B细胞淋巴瘤/白血病-2 （Bcl-2）、Bcl-2相关X蛋白（Bax）蛋白表达水平。两组间比较采用独立样本t检验,多组间比较采用单因素方差分析,组间两两比较采用LSD-t检验。 结果与癌旁组织相比,卵巢癌组织中RPL34-AS1表达水平降低（1.00±0.08比0.47±0.05）,miR-575表达水平升高（1.01±0.07比3.12±0.28）（P < 0.05）。转染si-RPL34-AS1后,细胞活性升高（48 h：0.68±0.06比0.55±0.05;72 h：0.99±0.08比0.71±0.06）,G1期细胞所占比例降低（13.42±1.38比32.15±2.11）,S期细胞所占比例升高（53.75±5.22比34.69±3.41）,细胞凋亡率降低（4.31±0.42比9.25±0.91）,CyclinD1、Bcl-2表达水平升高（0.92±0.08比0.71±0.07;0.86±0.07比0.61±0.06）,p21、Bax表达水平降低（0.13±0.02比0.29±0.03;0.19±0.02比0.31±0.03） （P均< 0.05）。RPL34-AS1靶向调控miR-575,过表达RPL34-AS1或抑制miR-575后可抑制细胞活性,阻滞细胞周期和促进细胞凋亡。miR-575过表达逆转了RPL34-AS1过表达对卵巢癌SKOV3细胞增殖抑制和凋亡促进的作用。 结论过表达RPL34-AS1可抑制卵巢癌SKOV3细胞增殖,促进细胞凋亡,其机制可能与下调miR-575有关。     

鼻息肉与鼻咽癌标本VEGF水平及微血管密度对比及其临床意义

目的:对比研究鼻咽癌和鼻息肉标本中VEGF表达强度及MVD差异,同时分析VEGF、MVD和鼻咽癌临床特征的相关性。方法:纳入我科就诊的鼻咽癌患者57例,鼻息肉患者50例。采用免疫组化SABC法检测癌组织、癌旁组织、及息肉组织中中VEGF蛋白的表达,及MVD强度。分析VEGF、MVD和鼻咽癌患者性别、临床分期、颈部淋巴结转移、远处转移、血清EBV-Ig A阳性、WHO病理分型相关性。统计分析随访结果,对可能影响鼻咽癌预后的因素进行Cox回归模型分析。结果:鼻咽癌组织、鼻咽癌旁组织、鼻息肉组织中VEGF表达、MVD强度具有明显差异(p0.05)。不同鼻咽癌临床分期、是否发生远处转移、不同WHO病理分型和VEGF表达、MVD强度具有明显差异(p0.05)。Cox回归方程显示,远处转移、病理分型、VEGF表达强度是影响鼻咽癌生存的独立危险因素(p0.05)。结论:鼻咽癌高表达VEGF,促进新生血管,形成高密度微小血管,和鼻咽癌远处转移密切相关,降低其生存率。     

热疗联合奥沙利铂对SW480细胞增殖和凋亡的影响

目的:观察奥沙利铂联合热疗对人结肠癌细胞SW480增殖及凋亡的影响,确定联合用药的效果,为临床方案提供参考。方法:采用MTT(四唑盐)法检测热疗、奥沙利铂及联合用药对细胞增殖的影响;瑞士吉姆萨染色法观察细胞形态;流式细胞仪检测细胞凋亡和周期;Western blot检测Bax、Bcl-2以及Caspase8蛋白表达量变化;q PCR检测Bax、Bcl-2以及Caspase8 m RNA的积累。结果:热疗联合奥沙利铂可以显著抑制细胞增殖,与对照组相比,热疗组、化疗组、联合组细胞凋亡率分别为16.2%、20.5%和36.1%,具有显著性差异(P0.01);细胞学形态中,热疗组细胞发生皱缩,化疗组细胞膜破裂;化疗将细胞阻滞在G2/M期,热疗和联合组将细胞阻滞S期;Western blot和qPCR显示Bax/Bcl-2比值上升,Caspase8表达量增加,联合组三种蛋白的表达量均与对照组具有显著性差异(P0.01)。结论:热疗联合奥沙利铂可以显著促进细胞凋亡,提高治疗效果,为结肠癌的治疗提供参考。     

幽门螺杆菌感染促进胃炎儿童胃粘膜细胞的增殖

本研究旨在探讨幽门螺杆菌感染对小儿慢性胃炎患者细胞增殖的影响,使用内镜检查消化不良患者的上消化道症状,使用改良的Giemsa染色检测胃粘膜活组织中幽门螺杆菌,用苏木精/曙红和改良的吉姆萨染色活组织,并通过光学显微镜研究染色后胃粘膜样品组织病理学变化,RT-PCR检测各组胃粘膜细胞中调控细胞凋亡的Bcl-2、Bcl-xl、Bax和PCNA的mRNA表达,提取胃粘膜细胞蛋白质,利用蛋白质免疫印迹分析蛋白质浓度。组织化学染色结果表明,与对照相比,患有胃炎和幽门杆菌感染后的胃炎患者胃粘膜细胞明显增加,且幽门螺杆菌感染后细胞增殖更显著(p<0.05);幽门螺杆菌感染后Bcl-2和Bcl-xl,PCNA在患者体内表达显著上调(p<0.05),而细胞促凋亡因子Bax基因在胃炎患者感染幽门螺杆菌后被显著下调(p<0.05),蛋白免疫印迹分析Bcl-2,Bcl-xl,Bax和PCNA蛋白表达趋势与基因表达一致,说明结果可靠。幽门螺杆菌感染会显著提高慢性胃炎儿童患者胃粘膜细胞的增殖。     

lncRNA ZFPM2-AS1 promotes proliferation via miR-18b-5p/VMA21 axis in lung adenocarcinoma

Lung cancer has been proved to be one of the most common kinds of cancers around the globe. Meanwhile, as the predominant type of lung cancer, lung adenocarcinoma (LUAD) has received increasing attention in cancer research. Long noncoding RNAs (lncRNAs) are known to be associated with oncogenesis and progression of various cancers. However, many lncRNAs have not been thoroughly detected in LUAD. In this study, through bioinformatics analysis we found that zinc finger protein multitype 2 antisense RNA 1 (ZFPM2-AS1) was associated with poor prognosis of LUAD patients. Also, ZFPM2-AS1 was detected to be overexpressed in LUAD tissues and cells. Furthermore, ZFPM2-AS1 could promote the proliferation of LUAD cells. Next, miR-18b-5p was found to bind with and negatively regulated by ZFPM2-AS1. VMA21, target gene of miR-18b-5p, could bind with and be negatively regulated by miR-18b-5p. More importantly, both ZFPM2-AS1 and VMA21 were found to be attached to the RNA-induced silencing complex constructed from miR-18b-5p and Ago2. Also, ZFPM2-AS1 could regulate the expression of VMA21. Therefore, ZFPM2-AS1 were confirmed to regulate VMA21 by competitively binding with miR-18b-5p. Finally, rescue assays confirmed that ZFPM2-AS1 could regulate LUAD cell proliferation via miR-18b-5p/VMA21 axis.     

Aberrant expression of lncRNAs SNHG6, TRPM2-AS1, MIR4435-2HG,and hypomethylation of TRPM2-AS1 promoter in colorectal cancer

Accumulating evidence has indicated that deregulation of lncRNAs plays essential roles in colorectal cancer (CRC) carcinogenesis. The goal of this study was to analyze the expression of lncRNAs in colorectal cancer and their association with clinicopathological variables. Bioinformatics analysis of published CRC microarray data was performed to identify the important lncRNAs. The expression levels of candidate genes were assessed in the human colon cancer/normal cell lines, CRC, adenomatous colorectal polyps, and their marginal tissues by qRT-PCR. Moreover, the methylation status of the TRPM2-AS1 promoter was studied using qMSP assay. Furthermore, we investigated the molecular mechanisms of these lncRNAs in CRC progression using in silico analysis. Microarray analysis revealed that lncRNAs SNHG6, MIR4435-2HG, and TRPM2-AS1 were upregulated in CRC. These results were validated in colon cell lines. Moreover, qRT-PCR showed that the expression levels of SNHG6 and TRPM2-AS1 were upregulated in the colorectal tumor tissues compared with their paired tissues. Nonetheless, there was no significant increase in MIR4435-2HG expression in CRC samples. Furthermore, we observed a significant hypomethylation of TRPM2-AS1 promoter and its activation in CRC tissues. By in silico analysis, we found that the lncRNAs upregulation could promote proliferation and drug resistance of colorectal cancer cells via miRNAs sponging and modulation of their targets expression. In conclusion, based on our results upregulation of SNHG6 and TRPM2-AS1, and hypomethylation of TRPM2-AS1 promoter might be considered as potential diagnostic biomarkers for CRC initiation and development.     

Type 2 cGMP-dependent protein kinase regulates proliferation and differentiation in the colonic mucosa

Signaling through cGMP has emerged as an important regulator of tissue homeostasis in the gastrointestinal tract, but the mechanism is not known. Type 2 cGMP-dependent protein kinase (PKG2) is a major cGMP effector in the gut epithelium, and the present studies have tested its importance in the regulation of proliferation and differentiation in the mouse colon and in colon cancer cell lines. Tissue homeostasis was examined in the proximal colon of Prkg2(-/-) mice using histological markers of proliferation and differentiation. The effect of ectopic PKG2 on proliferation and differentiation was tested in vitro using inducible colon cancer cell lines. PCR and luciferase reporter assays were used to determine the importance of Sox9 downstream of PKG2. The colons of Prkg2(-/-) mice exhibited crypt hyperplasia, increased epithelial apoptosis, and reduced numbers of differentiated goblet and enteroendocrine cells. Ectopic PKG2 was able to inhibit proliferation and induce Muc2 and CDX2 expression in colon cancer cells, but did not significantly affect cell death. PKG2 reduced Sox9 levels and signaling, suggesting possible involvement of this pathway downstream of cGMP in the colon. The work presented here demonstrates a novel antiproliferative and prodifferentiation role for PKG2 in the colon. These homeostatic functions of PKG2 were reproducible in colon cancer cells lines where downregulation of Sox9 is a possible mechanism. The similarities in phenotype between PKG2 and GCC knockout mice positions PKG2 as a likely mediator of the homeostatic effects of cGMP signaling in the colon.