PD-L1基因多态性与结直肠癌患者奥沙利铂化疗疗效和安全性的相关性研究

目的:研究PD-L1/3'-UTR上单核苷酸多态性rs4143815与结直肠癌患者奥沙利铂化疗疗效及安全性的相关性。方法:首先,测定262例接受奥沙利铂化疗的结直肠癌患者rs4143815的基因型;然后,统计分析基因型与奥沙利铂化疗疗效、不良反应发生情况及临床病理参数的相关性。结果:PD-L1/3'-UTR上单核苷酸多态性rs4143815与奥沙利铂治疗的疗效显著相关(P=0.028);与C/C型相比,C/G型患者的化疗疗效更好(OR=2.10),而G/G型患者的疗效却更差(OR=0.49)。然而,G/G型患者的不良反应发生率更低(OR=0.46)。此外,PD-L1/3'-UTR上单核苷酸多态性rs4143815与结直肠癌的肿瘤大小显著相关,G/G型患者的肿瘤体积比C/C型患者更小(R=0.08)。结论:rs4143815与奥沙利铂治疗结直肠癌患者的疗效、安全性和肿瘤大小显著相关,可能成为预测结直肠癌患者奥沙利铂治疗的疗效和安全性的参考分子标志物。     

Optimal Sequence of Irinotecan and Oxaliplatin-Based Regimens in Metastatic Colorectal Cancer: A Population-Based Observational Study

The optimal sequence of irinotecan and oxaliplatin-based regimens for metastatic colorectal cancer remains unclear. We conducted a population-based observational study by retrospectively reviewing records from Taiwan’s National Health Insurance Research Database to explore this issue. Patients aged ≥20 years with metastatic colorectal cancer newly diagnosed between 2004 and 2008 (n = 9490) were enrolled in current study. Among these 9490 patients, 3895 patients (41.04%) did not receive any chemotherapy within the first three months after catastrophic illness registration. Patients who received best supportive care were older and had higher Charlson comorbidity indexes and incidences of comorbidities than those who received irinotecan-based regimens, oxaliplatin-based regimens, and 5-fluorouracil/capecitabine alone. Patients who received irinotecan followed by oxaliplatin-based regimens and those who received the reverse sequence were further stratified into arm A (n = 542) and arm B (n = 1156), respectively. The median first time to next treatment was not significantly different between arm A and arm B (210 days vs. 196 days; p = 0.17). However, the median second time to next treatment was longer in arm A than in arm B (155 days vs. 123 days; p = 0.006), which translated into a better overall survival (487 days vs. 454 days; p = 0.02). The crossover rate was higher in arm A than in arm B (47.84% vs. 41.61%; p<0.001). Multivariate Cox regression analyses showed that overall survival was comparable between the two chemotherapy sequences (p = 0.27). Our study suggested that irinotecan followed by oxaliplatin-based regimens might be a better chemotherapy treatment option for metastatic colorectal cancer than the reverse sequence given the higher crossover rate and potential overall survival benefit.     

Differential kinetics of cell surface loss of von Willebrand factor and its propolypeptide after secretion from Weibel-Palade bodies in living human endothelial cells

The time course for cell surface loss of von Willebrand factor (VWF) and the propolypeptide of VWF (proregion) following exocytosis of individual Weibel-Palade bodies (WPBs) from single human endothelial cells was analyzed. Chimeras of enhanced green fluorescent protein (EGFP) and full-length pre-pro-VWF (VWF-EGFP) or the VWF propolypeptide (proregion-EGFP) were made and expressed in human umbilical vein endothelial cells. Expression of VWF-EGFP or proregion-EGFP resulted in fluorescent rod-shaped organelles that recruited the WPB membrane markers P-selectin and CD63. The WPB secretagogue histamine evoked exocytosis of these fluorescent WPBs and extracellular release of VWF-EGFP or proregion-EGFP. Secreted VWF-EGFP formed distinctive extracellular patches of fluorescence that were labeled with an extracellular antibody to VWF. The half-time for dispersal of VWF-EGFP from extracellular patches was 323.5 +/- 146.2 s (+/-S.D., n = 20 WPBs). In contrast, secreted proregion-EGFP did not form extracellular patches but dispersed rapidly from its site of release. The half-time for dispersal of proregion-EGFP following WPB exocytosis was 2.98 +/- 1.88 s (+/-S.D., n = 32 WPBs). The slow rate of loss of VWF-EGFP is consistent with the adhesive nature of this protein for the endothelial membrane. The much faster rate of loss of proregion-EGFP indicates that this protein does not interact strongly with extracellular VWF or the endothelial membrane and consequently may not play an adhesive role at the endothelial cell surface.     

Von Willebrand factor targets IL-8 to Weibel-Palade bodies in an endothelial cell line

Vascular endothelial cells are able to store the chemotactic cytokine interleukin-8 (IL-8) in specialized storage vesicles, Weibel-Palade bodies, together with von Willebrand factor (VWF) and P-selectin. We investigated whether VWF plays a role in the sorting of IL-8 into these organelles. We examined the effect of VWF expression on IL-8 targeting in an endothelial cell line (EC-RF24). This cell line has retained the typical phenotypic characteristics of primary endothelial cells but has lost the capacity to produce VWF in appreciable amounts. EC-RF24 cells were retrovirally transduced with a vector encoding a VWF-green fluorescent protein chimera (VWF-GFP). This approach enables direct visualization of the cellular distribution and secretory behavior of the VWF-GFP hybrid. Expression of VWF-GFP resulted in the generation of Weibel-Palade body-like organelles as shown by the colocalization of VWF-GFP and P-selectin. VWF-GFP expressing EC-RF24 cells also showed significant colocalization of VWF-GFP with IL-8 in these storage vesicles. Live cell imaging revealed that the number of VWF-GFP-containing granules decreased upon cell stimulation. These observations indicate that VWF plays an active role in sequestering IL-8 into Weibel-Palade bodies.     

Intracellular storage and regulated secretion of von Willebrand factor in quantitative von Willebrand disease

Several missense mutations in the von Willebrand Factor (VWF) gene of von Willebrand disease (VWD) patients have been shown to cause impaired constitutive secretion and intracellular retention of VWF. However, the effects of those mutations on the intracellular storage in Weibel-Palade bodies (WPBs) of endothelial cells and regulated secretion of VWF remain unknown. We demonstrate, by expression of quantitative VWF mutants in HEK293 cells, that four missense mutations in the D3 and CK-domain of VWF diminished the storage in pseudo-WPBs, and led to retention of VWF within the endoplasmic reticulum (ER). Immunofluorescence and electron microscopy data showed that the pseudo-WPBs formed by missense mutant C1060Y are indistinguishable from those formed by normal VWF. C1149R, C2739Y, and C2754W formed relatively few pseudo-WPBs, which were often short and sometimes round rather than cigar-shaped. The regulated secretion of VWF was impaired slightly for C1060Y but severely for C1149R, C2739Y, and C2754W. Upon co-transfection with wild-type VWF, both intracellular storage and regulated secretion of all mutants were (partly) corrected. In conclusion, defects in the intracellular storage and regulated secretion of VWF following ER retention may be a common mechanism underlying VWD with a quantitative deficiency of VWF.     

血清VEGF水平与贝伐珠单抗联合化疗治疗转移性结直肠癌患者疗效的关系研究

目的:研究血清血管内皮生长因子(VEGF)水平与贝伐珠单抗联合化疗治疗转移性结直肠癌患者疗效的关系。方法:选取2015年2月至2016年2月间我院收治的转移性结直肠癌患者80例,按照数字随机表法将患者随机分为观察组(n=40)和对照组(n=40)。对照组给予氟尿嘧啶/奥沙利铂(FOLFOX-6)方案治疗,观察组则在此基础上加用贝伐珠单抗5 mg/kg治疗,d1,两组均进行4个化疗周期,比较两组患者临床疗效及治疗前、治疗后血清VEGF水平,并分析血清VEGF与疗效的相关性。结果:观察组有效率(RR)为52.50%(21/40),高于对照组的30.00%(12/40)(P0.05)。治疗前两组患者血清VEGF水平差异无统计学意义(P0.05),治疗后两组患者血清VEGF水平均较治疗前显著降低,观察组患者血清VEGF水平显著低于对照组患者,观察组VEGF下降幅度显著高于对照组(均P0.05)。经秩相关分析显示,结直肠癌患者治疗后VEGF下降幅度与治疗疗效呈显著正相关(r=0.683,P=0.000)。结论:贝伐珠单抗联合化疗治疗转移性结直肠癌可显著降低患者血清VEGF水平,疗效更佳。     

No Survival Benefit from Adding Cetuximab or Panitumumab to Oxaliplatin-Based Chemotherapy in the First-Line Treatment of Metastatic Colorectal Cancer in KRAS Wild Type Patients: A Meta-Analysis

Background

The efficacy of combined therapies of oxaliplatin-based chemotherapy and anti-epidermal growth factor receptor (anti-EGFR) monoclonal antibodies (MAbs) remains controversial in colorectal cancer (CRC). The aim of this study is to estimate the efficacy and safety of adding cetuximab or panitumumab to oxaliplatin-based chemotherapy in the first line treatment in KRAS wild type patients with metastatic colorectal cancer (mCRC) through meta-analysis.

Methods

Medline, EMBASE, and Cochrane library, American Society of Clinical Oncology (ASCO) and European Society for Medical Oncology (ESMO) were searched. Eligible studies were randomized controlled trials (RCTs) which evaluated oxaliplatin-based chemotherapy with or without anti-EGFR drugs (cetuximab or panitumumab) in untreated KRAS wild type patients with mCRC. The outcomes included overall survival (OS), progression-free survival (PFS), overall response rate (ORR) and toxicities. Hazard ratios (HR) and risk ratio (RR) were used for the meta-analysis and were expressed with 95% confidence intervals.

Results

This meta-analysis included four RCTs with 1270 patients, and all of the patients were administered oxaliplatin-based chemotherapy regimens with or without anti-EGFR MAbs. The result of heterogeneity of OS was not significant. Compared with chemotherapy alone, the addition of cetuximab or panitumumab didn’t result in significant improvement in OS (HR = 1.00, 95%CI [0.88, 1.13], P = 0.95) or PFS (HR = 0.86, 95%CI [0.71, 1.04], P = 0.13). The subgroup analysis of cetuximab also revealed no significant benefit in OS (HR = 1.02, 95%CI [0.89, 1.18], P = 0.75) or in PFS (HR = 0.87, 95%CI [0.65, 1.17], P = 0.36). Patients who received combined therapy didn’t have a higher ORR (Risk Ratio = 1.08, 95%CI [0.86, 1.36]). Toxicities slightly increased in anti-EGFR drugs group.

Conclusions

The addition of cetuximab or panitumumab to oxaliplatin-based chemotherapy in first-line treatment of mCRC in wild type KRAS population did not improve efficacy in survival benefit and response rate. More RCTs are warranted to evaluate the combination of chemotherapy and targeted therapy.     

Oxaliplatin-based Chemotherapy Might Provide Longer Progression-Free Survival in KRAS Mutant Metastatic Colorectal Cancer

The identification of better regimens in currently available chemotherapeutic agents is crucial for treating patients with KRAS mutant metastatic colorectal cancer (mCRC). Records of mCRC patients who received first-line oxaliplatin- based or irinotecan-based regimens were reviewed retrospectively. Clinicopathologic features and treatment outcome of patients with first-line progression-free survival (PFS) and overall survival (OS) in association with KRAS mutation status were analyzed using the Cox proportional hazard model. Between 2007 and 2010, a total of 118 mCRC patients were enrolled. Among them, 67 were males and 51 were females. In patients who received first-line oxaliplatin-based regimens, the PFS was significantly longer in KRAS mutant patients (N = 32) than that in KRAS wild-type patients (N = 51). The median PFS was 8.5 months in KRAS mutant versus 5.8 months in KRAS wild-type patients (P = .008). In contrast, in patients who received first-line irinotecan-based regimens, the PFS was shorter in KRAS mutant patients (N = 15) than that in KRAS wild-type patients (N = 20). Median PFS was 3.9 months in KRAS mutant versus 6.0 months in KRAS wild-type patients (P = .23). Median OS between KRAS mutant and wild-type patients was not significantly different in both oxaliplatin-based and irinotecan-based regimens. In multivariate analyses, KRAS mutation remains an independent predictive factor for longer PFS in first-line oxaliplatin-based regimens. In conclusion, oxaliplatin-based chemotherapy in KRAS mutant mCRC might result in longer PFS than in KRAS wild-type mCRC.     

Endothelial cell confluence regulates Weibel-Palade body formation

Secretory granules called Weibel-Palade bodies (WPBs) containing Von Willebrand factor (VWF) are characteristic of the mammalian endothelium. We hypothesized that vascular-specific antigens such as VWF are linked to endothelial identity and proliferation in vitro. To test this idea, the cellular accumulation of VWF in WPBs was monitored as a function of cell proliferation, confluence and passage number in human umbilical vein endothelial cells (HUVECs). We found that as passage number increased the percentage of cells containing VWF in WPBs was reduced significantly, whilst the protein was still detected within the secretory pathway at all times. However, the endothelial-specific marker protein, PECAM-1, is present on all cells even when WPBs are absent, indicating partial maintenance of endothelial identity. Biochemical studies show that a significant pool of immature pro-VWF can be detected in sub-confluent HUVECs; however, a larger pool of mature, processed VWF is detected in confluent cells. Newly synthesized VWF must thus be differentially sorted and packaged along the secretory pathway in semi-confluent versus confluent endothelial cells. Our studies thus show that WPB formation is linked to the formation of a confluent endothelial monolayer.     

Endothelial cell confluence regulates Weibel-Palade body formation

Secretory granules called Weibel-Palade bodies (WPBs) containing Von Willebrand factor (VWF) are characteristic of the mammalian endothelium. We hypothesized that vascular-specific antigens such as VWF are linked to endothelial identity and proliferation in vitro. To test this idea, the cellular accumulation of VWF in WPBs was monitored as a function of cell proliferation, confluence and passage number in human umbilical vein endothelial cells (HUVECs). We found that as passage number increased the percentage of cells containing VWF in WPBs was reduced significantly, whilst the protein was still detected within the secretory pathway at all times. However, the endothelial-specific marker protein, PECAM-1, is present on all cells even when WPBs are absent, indicating partial maintenance of endothelial identity. Biochemical studies show that a significant pool of immature pro-VWF can be detected in sub-confluent HUVECs; however, a larger pool of mature, processed VWF is detected in confluent cells. Newly synthesized VWF must thus be differentially sorted and packaged along the secretory pathway in semi-confluent versus confluent endothelial cells. Our studies thus show that WPB formation is linked to the formation of a confluent endothelial monolayer.     

Complex Changes in von Willebrand Factor-Associated Parameters Are Acquired during Uncomplicated Pregnancy

Background

The coagulation protein von Willebrand Factor (VWF) is known to be elevated in pregnancy. However, the timing and nature of changes in VWF and associated parameters throughout pregnancy are not well understood.

Objectives

To better understand the changes in VWF provoked by pregnancy, we studied VWF-associated parameters in samples collected over the course of healthy pregnancies.

Methods

We measured VWF antigen (VWF:Ag), VWF propeptide (VWFpp), Factor VIII (FVIII), and ADAMTS13 activity in samples collected from 46 women during pregnancy and at non-pregnant baseline. We also characterized pregnant vs. non-pregnant VWF multimer structure in 21 pregnancies, and performed isoelectric focusing (IEF) of VWF in two pregnancies which had samples from multiple trimesters.

Results

VWF:Ag and FVIII levels were significantly increased during pregnancy. ADAMTS13 activity was unchanged. VWFpp levels increased much later in pregnancy than VWF:Ag, resulting in a progressive decrease in VWFpp:Ag ratios. FVIII:VWF ratios also decreased in pregnancy. Most pregnancies exhibited a clear loss of larger VWF multimers and altered VWF triplet structure. Further evidence of acquired VWF qualitative changes in pregnancy was found in progressive, reversible shifts in VWF IEF patterns over gestation.

Conclusions

These data support a new view of pregnancy in which VWF can acquire qualitative changes associated with advancing gestational age. Modeling supports a scenario in which both increased VWF production and doubling of the VWF half-life would account for the data observed. We propose that gestation induces a prolongation in VWF survival, which likely contributes to increased total VWF levels and altered VWF structure.     

Coagulation Activation in Children with Sickle Cell Disease Is Associated with Cerebral Small Vessel Vasculopathy

Background

Thrombotic complications in Sickle Cell Disease (SCD) arise since infancy, but the role of the coagulation system in children has been poorly explored. To determine its role in the development of clinical complications in childhood we measured coagulation and endothelial parameters in children with SCD at steady state.

Methods

Markers of thrombin generation, fibrin dissolution and endothelial activation were evaluated in 38 children with SS-Sβ°, 6 with SC disease and 50 age and blood group matched controls. Coagulation variables were correlated with markers of hemolysis and inflammation, with the presence of cerebral and lung vasculopathy and with the frequency of clinical complications.

Results

SS-Sβ° patients presented higher levels of factor VIII, von Willebrand factor antigen (VWF:Ag) and collagen binding activity, tissue plasminogen activator antigen (t-PA:Ag), D-dimer, p-selectin, prothrombin fragment1+2 (F1+2) and lower ADAMTS-13:activity/VWF:Ag (p<0.05) compared to controls and SC patients. In SS-Sβ° patients coagulation variables correlated positively with markers of inflammation, hemolysis, and negatively with HbF (p<0.05). Patients with cerebral silent infarcts showed significant decrease in t-PA:Ag and ADAMTS-13 Antigen and a tendency toward higher D-dimer, F1+2, TAT compared to patients without them. D-dimer was associated with a six fold increased risk of cerebral silent infarcts. No correlation was found between coagulation activation and large vessel vasculopathy or other clinical events except for decreased t-PA:Ag in patients with tricuspid Rigurgitant Velocity >2.5m/sec.

Conclusions

SS-Sβ° disease is associated with extensive activation of the coagulation system at steady state since young age. ADAMTS-13 and t-PA:Ag are involved in the development of cerebral silent infarcts.     

Does the Chemotherapy Backbone Impact on the Efficacy of Targeted Agents in Metastatic Colorectal Cancer? A Systematic Review and Meta-Analysis of the Literature

ImportanceThe EGFR inhibitors (EGFR-I) cetuximab and panitumumab and the angiogenesis inhibitors (AIs) bevacizumab and aflibercept have demonstrated varying efficacy in mCRC.ObjectiveTo document the overall impact of specific chemotherapy regimens on the efficacy of targeted agents in treating patients with mCRC. Data sources: MEDLINE, EMBASE and Cochrane databases were searched to 2014, supplemented by hand-searching ASCO/ESMO conference abstracts.ResultsEGFR-I added to irinotecan-based chemotherapy modestly improved OS with HR 0.90 (95% CI 0.81–1.00, p = 0.04), but more so PFS with HR 0.77 (95% CI 0.69–0.86, p<0.00001). No benefit was evident for EGFR-I added to oxaliplatin-based chemotherapy (OS HR 0.97 (95% CI 0.87–1.09) and PFS HR 0.92 (95% CI 0.83–1.02)). Significant oxaliplatin-irinotecan subgroup interactions were present for PFS with I² = 82%, p = 0.02. Further analyses of oxaliplatin+EGFR-I trials showed greater efficacy with infusional 5FU regimens (PFS HR 0.82, 95% CI 0.72–0.94) compared to capecitabine (HR 1.09; 95% CI 0.91–1.30) and bolus 5FU (HR 1.07; 95% CI 0.79–1.45); subgroup interaction was present with I² = 72%, p = 0.03. The oxaliplatin-irinotecan interaction was not evident for infusional 5FU regimens. For AIs, OS benefit was observed with both oxaliplatin-based (HR 0.83) and irinotecan-based (HR 0.77) regimens without significant subgroup interactions. Oxaliplatin+AI trials showed no subgroup interactions by type of FP, whilst an interaction was present for irinotecan+AI trials although aflibercept was only used with infusional FP (I² = 89.7%, p = 0.002).

Conclusion and Relevance

The addition of EGFR-I to irinotecan-based chemotherapy has consistent efficacy, regardless of FP regimen, whereas EGFR-I and oxaliplatin-based regimens were most active with infusional 5FU. No such differential activity was observed with the varying chemotherapy schedules when combined with AIs.     

Interaction of Shiga Toxin with the A-domains and Multimers of von Willebrand Factor

Shiga toxin (Stx) produced by enterohemorrhagic Escherichia coli causes diarrhea-associated hemolytic-uremic syndrome (DHUS), a severe renal thrombotic microangiopathy. We investigated the interaction between Stx and von Willebrand Factor (VWF), a multimeric plasma glycoprotein that mediates platelet adhesion, activation, and aggregation. Stx bound to ultra-large VWF (ULVWF) secreted from and anchored to stimulated human umbilical vein endothelial cells, as well as to immobilized VWF-rich human umbilical vein endothelial cell supernatant. This Stx binding was localized to the A1 and A2 domain of VWF monomeric subunits and reduced the rate of ADAMTS-13-mediated cleavage of the Tyr¹⁶⁰⁵-Met¹⁶⁰⁶ peptide bond in the A2 domain. Stx-VWF interaction and the associated delay in ADAMTS-13-mediated cleavage of VWF may contribute to the pathophysiology of DHUS.     

Regulatory Components of the Alternative Complement Pathway in Endothelial Cell Cytoplasm,Factor H and Factor I,Are Not Packaged in Weibel-Palade Bodies

It was recently reported that factor H, a regulatory component of the alternative complement pathway, is stored with von Willebrand factor (VWF) in the Weibel-Palade bodies of endothelial cells. If this were to be the case, it would have therapeutic importance for patients with the atypical hemolytic-uremic syndrome that can be caused either by a heterozygous defect in the factor H gene or by the presence of an autoantibody against factor H. The in vivo Weibel-Palade body secretagogue, des-amino-D-arginine vasopressin (DDAVP), would be expected to increase transiently the circulating factor H levels, in addition to increasing the circulating levels of VWF. We describe experiments demonstrating that factor H is released from endothelial cell cytoplasm without a secondary storage site. These experiments showed that factor H is not stored with VWF in endothelial cell Weibel-Palade bodies, and is not secreted in response in vitro in response to the Weibel-Palade body secretagogue, histamine. Furthermore, the in vivo Weibel-Palade body secretagogue, DDAVP does not increase the circulating factor H levels concomitantly with DDAVP-induced increased VWF. Factor I, a regulatory component of the alternative complement pathway that is functionally related to factor H, is also located in endothelial cell cytoplasm, and is also not present in endothelial cell Weibel-Palade bodies. Our data demonstrate that the factor H and factor I regulatory proteins of the alternative complement pathway are not stored in Weibel-Palade bodies. DDAVP induces the secretion into human plasma of VWF —- but not factor H.     

BLOC-2 subunit HPS6 deficiency affects the tubulation and secretion of von Willebrand factor from mouse endothelial cells

Hermansky-Pudlak syndrome(HPS) is a recessive disorder with bleeding diathesis, which has been linked to platelet granule defects. Both platelet granules and endothelial Weibel-Palade bodies(WPBs)are members of lysosome-related organelles(LROs) whose formation is regulated by HPS protein associated complexes such as BLOC(biogenesis of lysosome-related organelles complex)-1,-2,-3, AP-3(adaptor protein complex-3) and HOPS(homotypic fusion and protein sorting complex). Von Willebrand factor(VWF) is critical to hemostasis, which is stored in a highly-multimerized form as tubules in the WPBs. In this study, we found the defective, but varying, release of VWF into plasma after desmopressin(DDAVP) stimulation in HPS1(BLOC-3 subunit), HPS6(BLOC-2 subunit), and HPS9(BLOC-1 subunit)deficient mice. In particular, VWF tubulation, a critical step in VWF maturation, was impaired in HPS6 deficient WPBs. This likely reflects a defective endothelium, contributing to the bleeding tendency in HPS mice or patients. The differentially defective regulated release of VWF in these HPS mouse models suggests the need for precise HPS genotyping before DDAVP administration to HPS patients.     

Co-distribution of von Willebrand factor and fibronectin in cultured rhesus endothelial cells

Summary The synthesis and secretion of von Willebrand factor (VWF, or Factor VIII-related antigen) and fibronectin by cultured endothelial cells from rhesus monkey choroid retina were demonstrated by immunofluorescence, immunoperoxidase and single radial immunodiffusion techniques. Both VWF and fibronectin are localized in intracellular granules and extracellular fibrils. The results of double immunofluorescence staining and post-embedding immunoelectron microscopy showed that there was a co-distribution of VWF and fibronectin not only in pericellular fibrils where they co-aligned with each other to be the components of extracellular matrix, but also in intracellular granules, suggesting they were synthesized or translocated in the same compartment.     

贝伐单抗二线治疗转移性结直肠癌的临床观察

目的:观察贝伐单抗二线治疗转移性结直肠癌患者的临床疗效和毒副反应。方法:回顾性分析2008年8月至2011年10月我院经组织病理学证实的转移性结直肠癌患者21例,一线治疗进展后,二线治疗方案中加用贝伐单抗,用法为5mg/kg,每2-3周1次,与化疗方案同步。化疗方案以奥沙利铂及伊立替康为基础,完成2-3周期治疗后评定疗效,观察毒副反应。结果:21例患者中PR1例,SD11例,PD9例,客观缓解率为4.8%,疾病控制率为57.1%,中位TTP为3.7个月。患者出现的不良反应有骨髓抑制、皮疹、恶心呕吐、腹泻、肝功能损害、神经毒性等,贝伐单抗所致高血压的发生率为14.3%(3/21),鼻衄发生率为4%(2/21)。结论:二线治疗中使用贝伐单抗,对一线治疗进展后的转移性结直肠癌疗效有限,毒副反应可耐受。     

The NFY transcription factor inhibits von Willebrand factor promoter activation in non-endothelial cells through recruitment of histone deacetylases

Human von Willebrand factor (VWF) gene sequences +155 to +247 contain cis-acting elements that contribute toward endothelial specific activation of the VWF promoter. Analyses of this region demonstrated the presence of a GATA-binding site that is necessary for the promoter activation in endothelial cells. We have reported recently the presence of a novel NFY-binding sequence in this region that does not conform to the consensus NFY-binding sequence CCAAT. NFY was shown to function as a repressor of the VWF promoter through interaction with this novel binding site. Here we report that the NFY interacts with histone deacetylases (HDACs) in a cell type-specific manner and recruits them to the VWF promoter to inhibit the promoter activity in non-endothelial cells. Analyses of the acetylation status of histones in the chromatin region containing the VWF promoter sequences demonstrated that these sequences are associated with acetylated histone H4 specifically in endothelial cells. It was also demonstrated that HDACs are specifically recruited to the same chromatin region in non-endothelial cells. We also demonstrated that GATA6 is the GATA family member that interacts with the VWF promoter and that GATA6 is associated with NFY specifically in non-endothelial cells. We propose that NFY recruits HDACs to the VWF promoter, which may result in deacetylation of GATA6 as well as of histones in non-endothelial cells, thus leading to promoter inactivation. In endothelial cells, however, association of HDACs, NFY, and GATA6 is interrupted potentially through endothelial cell-specific signaling/mechanism, thus favoring the balance toward acetylation and activation of the VWF promoter.