Lnc-AC145676.2.1-6-3 can influence STX3-induced abnormal autophagy by sponging hsa-miR-1292-3p in intestinal aGVHD

OBJECTIVE

Intestinal acute graft-versus-host disease (aGVHD) is a serious complication of allogeneic hematopoietic stem cell transplantation (allo-HSCT). Abnormal autophagy levels in intestinal aGVHD have been confirmed in many studies. LncRNAs exert coregulatory functions and participate in a variety of intracellular regulatory processes. In this study, we investigated how lnc-AC145676.2.1-6-3 regulates dysregulated STX3-related autophagy in aGVHD.

MATERIALS AND METHODS

First, we established a mouse model of aGVHD by transplanting a mononuclear cell suspension from Balb/c donor mice treated with 60Co X-rays into CB6F1 recipient mice. STX3-related indicators were analyzed by Western blotting (WB) and immunohistochemistry which confirmed that STX3 plays an important role in dysregulating autophagy in intestinal aGVHD. TNF-αinduced Caco-2 cells, which is an in vitro model of intestinal barrier dysfunction, were established to verify the effect of STX3. The direct interaction between the partners of lnc-AC145676.2.1-6-3-mediated hsa-miR-1292-3p and STX3 axis was evaluated by the Dual-Luciferase activity assay. We performed PCR, WB, and immunofluorescence in Caco-2 cells to determine whether the abnormal autophagy levels were influenced by lnc-AC145676.2.1-6-3.

RESULTS

The results showed that lnc-AC145676.2.1-6-3 could significantly suppress the number of autophagic vacuoles, the LC3-II/I ratio, and beclin1 levels by increasing STX3 levels.

CONCLUSIONS

Lnc-AC145676.2.1-6-3 may play an important role in intestinal aGVHD by targeting STX3.

[CART therapy followed by allo-HSCT for patients with B-cell acute lymphoblastic leukemia relapsing after the first hematopoietic stem cell transplantation]

目的

观察嵌合抗原受体T细胞（CART）序贯二次异基因造血干细胞移植（allo-HSCT）治疗移植后复发急性B淋巴细胞白血病（B-ALL）的疗效。

方法

回顾性分析2015年10月至2020年6月在河北燕达陆道培医院接受二次allo-HSCT的41例B-ALL患者的临床资料，入选患者均为移植后骨髓形态学或髓外复发且二次移植前接受CART治疗。

结果

全部41例患者中男21例、女20例，二次移植时中位年龄为16（3～46）岁。移植后骨髓复发31例（75.6％）、髓外复发5例（12.2％）、骨髓和髓外复发5例（12.2％）。复发后接受CD19-CART治疗35例（85.4％）、CD22-CART治疗2例（4.9％）、CD19-CART联合CD22-CART治疗4例（9.8％）。二次移植后预期3年总生存（OS）率为48.9％（95％ CI 23.0％～70.6％）、无白血病生存（LFS）率为41.8％（95％ CI 17.3％～64.9％），累积复发率（RI）为8.8％（95％ CI 2.9％～26.4％），非复发相关死亡率（NRM）为51.1％（95％ CI 31.2％～83.6％）。首次移植后复发时间≤6个月组（10例）二次移植后1年OS率低于复发时间>6个月组（31例）［45.0％（95％ CI 12.7％～73.5％）对75.0％（95％ CI 51.4％～88.8％），P＝0.017］。

结论

CART序贯二次allo-HSCT可使部分造血干细胞移植后复发B-ALL患者获得长生存，但NRM较高，移植方案有待进一步改进。

[Comparison of the clinical outcomes of haploidentical and matched-sibling donor stem cell transplantation for T cell acute lymphoblastic leukemia in complete remission]

目的

比较亲缘单倍型造血干细胞移植（HIDT）和同胞相合造血干细胞移植（MSDT）治疗完全缓解期（CR）急性T淋巴细胞白血病（T-ALL）的疗效。

方法

回顾性分析2012年5月至2017年5月间在河北燕达陆道培医院接受HIDT（81例）和MSDT（17例）的CR期T-ALL患者的临床特点和预后。

结果

HIDT组、MSDT组移植后100 d Ⅱ～Ⅳ度急性GVHD发生率分别为51.9％（95％CI42.0％～64.0％）、29.4％（95％CI 14.1％～61.4％）（P＝0.072），Ⅲ/Ⅳ度急性GVHD发生率分别为9.8％（95％CI 5.1％～19.1％）、11.8％（95％CI 3.2％～43.3％）（P＝1.000），巨细胞病毒（CMV）血症发生率分别为53.1％（95％CI 43.3％～65.2％）、29.4％（95％CI 14.1％～61.4％）（P＝0.115），EB病毒（EBV）血症发生率分别为35.8％（95％CI 26.8％～47.9％）、11.8％（95％CI 3.2％～43.3％）（P＝0.048）。HIDT、MSDT两组移植后5年总生存（OS）率分别为60.5％（95％CI 5.4％～49.0％）、68.8％（95％CI 11.8％～40.0％）（P＝0.315），无白血病生存（LFS）率分别为58.0％（95％CI 5.5％～46.5％）、68.8％（95％CI11.8％～40.0％）（P＝0.258），累积复发率分别为16.1％（95％ CI 9.8％～26.4％）、11.8％（95％ CI3.2％～43.3％）（P＝0.643），非复发死亡率（NRM）分别为25.9％（95％CI 17.9％～37.5％）、19.4％（95％CI6.9％～54.4％）（P＝0.386）。

结论

对于CR期T-ALL患者，当缺乏合适供者时，HIDT可作为替代选择。

[Threshold effects of body mass index on the bone mineral density of Chinese rural women in fluorosis area]

To explore the threshold effect of body mass index (BMI) on bone mineral density (BMD) in Chinese women living in the fluorosis area, we conducted a cross-sectional study and recruited 722 women in rural areas in Henan Province, China. After detection and analyses, we found that compared with the normal BMI group, the risk of osteoporosis in the overweight and obese groups were reduced by 32% and 69%, respectively. Threshold effect analysis showed that BMD was positively correlated with BMI when BMI was 16.8-31.2 kg/m²; while when BMI was greater than 31.2 kg/m², the correlation reached saturation. The correlation observed between low-to-moderate fluoride exposure and BMD in rural women was not significant.

[Prognostic analysis of allogeneic hematopoietic stem cell transplantation for Philadelphia chromosome-positive acute lymphoblastic leukemia in complete remission in the era of tyrosine kinase inhibitors]

目的

探讨在酪氨酸激酶抑制剂（TKI）时代Ph染色体阳性急性淋巴细胞白血病（Ph⁺ALL）在完全缓解（CR）状态下行异基因造血干细胞移植（allo-HSCT）的预后和影响因素。

方法

回顾性分析2012年5月至2017年5月河北燕达陆道培医院收治的116例在CR状态下行allo-HSCT的Ph⁺ALL患者的预后及其影响因素。

结果

116例患者中男72例，女44例。中位年龄20（4～64）岁。同胞全相合移植21例，亲缘单倍型移植77例，非血缘移植18例。5年总生存（OS）率为73.2％（95％CI 63.8％～80.5％），其中诊断至移植间隔时间<180 d的亚组5年OS率为87.5％。5年无病生存（DFS）率为61.4％（95％CI 51.8％～69.7％）。5年细胞形态及分子学水平复发累积发生率为18.5％（95％CI 12.6％～27.3％）。5年移植相关死亡率（TRM）为19.9％（95％CI 13.8％～28.7％）。多因素分析显示，15～39岁（HR＝2.730，P＝0.044）、诊断至移植间隔时间≥180 d（HR＝4.534，P＝0.010）、发生Ⅲ～Ⅳ度急性移植物抗宿主病（aGVHD）（HR＝7.558，P＝0.000）是影响患者OS的不利因素；发生局限型慢性移植物抗宿主病（cGVHD）是影响患者OS的有利因素（HR＝0.300，P＝0.034）。而性别、起病时WBC（<30×10⁹/L，≥30×10⁹/L）、BCR-ABL融合基因类型、体细胞突变类型、移植前状态（CR₁，>CR₁）、移植前微小残留病（MRD）水平（MRD阴性，MRD阳性）、预处理方案（全身照射方案，白消安为基础方案）、预处理方案强度、移植类型、GVHD预防方案（环孢素A，他克莫司）、抗胸腺细胞免疫球蛋白的种类、巨细胞病毒和EB病毒血症的有无对OS的影响无统计学意义。

结论

TKI时代Ph⁺ALL在CR状态下行allo-HSCT时，影响生存的因素有年龄、诊断至移植间隔时间和发生重度aGVHD。

[Comparison of three different types of donor hematopoietic stem cell transplantation for intermediate and high-risk myelodysplastic syndrome]

目的

比较半相合移植（Haplo-HSCT）、无关供者移植（MUD-HSCT）及同胞相合移植（MSD-HSCT）治疗中高危骨髓增生异常综合征（MDS）的疗效及其预后影响因素。

方法

回顾性分析2001年8月至2015年5月接受异基因造血干细胞移植（allo-HSCT）治疗的167例中高危MDS患者病例资料，比较不同移植方式下患者的预后特征及预后影响因素。

结果

存活患者中位随访60（12~177）个月。5年实际累积无病生存（DFS）率为67.8%（95% CI 60.0%~75.6%），其中MSD-HSCT组为68.0%（95% CI 54.1%~81.9%），MUD-HSCT组为77.4%（95% CI 62.1%~92.7%），Haplo-HSCT组为64.0%（95% CI 52.4%~75.6%），三组比较差异无统计学意义（P=0.632）。单因素分析结果显示移植前病程>12个月者累积DFS率明显低于≤12个月者（P=0.018）。5年累积复发死亡率和移植相关死亡率（TRM）与上面危险因素均无明显相关性。

结论

Haplo-HSCT治疗MDS疗效显著，可以作为重要的替代供者，特别是在缺乏MSD而病情紧急没有时间去等待搜索MUD的情况下，可以主动选择；移植前病程是影响DFS的重要因素。

Short-term effect of metronomic chemotherapy of low-dose Tegafur on patients with primary hepatic carcinoma after radiofrequency ablation

OBJECTIVE

To investigate the therapeutic effect of metronomic chemotherapy with low-dose Tegafur on patients with primary hepatic carcinoma (PHC) after radiofrequency ablation (RFA).

PATIENTS AND METHODS

PHC patients who underwent RFA were assigned to RFA + Tegafur group and RFA group, respectively. Patients in RFA + Tegafur group received metronomic chemotherapy with low-dose Tegafur after RFA. PHC patients in RFA group only received radiofrequency ablation. Therapeutic efficacy of the two groups was prospectively analyzed within 18 months after RFA. Disease control rate (DCR) and progression-free survival (PFS) in both groups were evaluated.

RESULTS

Follow-up data showed that DCR in RFA + Tegafur group and RFA group at 9 months after RFA was 93.3% and 73.4%, respectively (p=0.038). Within the 18-month follow-up, median PFS in RFA + Tegafur group and RFA group was 16.25 months and 12.25 months, respectively (p<0.001). One-year PFS in RFA group was 53.3%, which was remarkably lower than that of RFA + Tegafur group (83.3%, p=0.012). Moreover, the prevalence of major complications in the present study was 13.3%. No treatment-related death occurred in both groups.

CONCLUSIONS

Metronomic chemotherapy with low-dose Tegafur after RFA can slow down tumor progression and prolong the progression-free survival of PHC patients.

[Effect of NCCN (2015) risk stratification on prognosis of patients with acute myeloid leukemia after allogeneic hematopoietic stem cell transplantation]

Objective: To analyze the effect of NCCN (2015) risk stratification on prognosis of patients with acute myeloid leukemia (AML) after allogeneic hematopoietic stem cell transplantation (allo-HSCT) . Methods: Retrospective analysis of 258 patients with AML in CR (186 cases in CR(1), 72 cases in CR(2)) who underwent allogeneic HSCT in our hospital between April 2012 and March 2015 according to NCCN (2015) risk stratification. Of them, 63 cases were classified as low risk, 112 cases intermediate risk and 83 cases high risk. Results: ①With the median follow up of 18 (5-41) months, two-year disease free surviva (DFS) in 258 patients was 78.0% (95% CI 60.4%-96.6%) . Two-year DFS in AML after transplantation was 78.6% (95% CI 61.0%-96.2%) in low risk, 76.0% (95% CI 84.0%-93.6%) in intermediate risk and 80.3% (95% CI 62.7%-97.9%) (P=0.886) in high risk groups respectively. ②Univariate analysis showed that DFS has no significant difference in patient age, the median disease course before HSCT, the WBC number at the beginning of the disease, blood routine and chromosomes examination before transplantation, extramedullary disease before transplantation, disease status before transplantation, conditioning regimen, donor type, donor and recipient sex, recipient blood type, transfused MNC number, transfused CD34(+) cell number and transfused CD3(+) cell number. DFS was significant lower in primary AML than that in secondary AML (P=0.006) and also lower in MRD positive than that in MRD negative (P=0.003) . The accumulative relapse was significant higher in CR(2) compared to that in CR(1) (P=0.046) . Accumulative non-relapse mortality (NRM) was significanlyt higher in secondary AML compared to that in primary AML (P=0.004) and also higher in MRD positive compared to that in MRD negative (P=0.010) . ③Multivariate analysis showed that MRD positive was the only significant factor in DFS and NRM. Conclusion: Allo-HSCT treatment of AML CR patients could achieve a high efficacy, which is similar between CR(1) and CR(2) patients. There is no significant correlation between NCCN (2015) risk stratification and the prognosis of AML patients with allo-HSCT treatment. Pre-conditioning MRD status monitored by multiparameter flow cytometry was the only impact factor on DFS and NRM in allo-HSCT for CR-AML patients.

[Effect of minimal residual disease monitoring by multiparameter flow cytometry pre-conditioning on prognosis of acute myeloid leukemia after allogeneic hematopoietic stem cell transplantation]

目的

分析预处理前多参数流式细胞术（MFC）监测的骨髓微小残留病（MRD）对急性髓系白血病（AML）异基因造血干细胞移植（allo-HSCT）预后的影响，探讨MFC监测MRD在AML allo-HSCT预后评估中的价值。

方法

回顾性分析2012年4月至2015年3月行allo-HSCT的186例AML患者，预处理前骨髓细胞形态学均达第1次完全缓解（CR₁）。采用8色MFC对预处理前骨髓进行MRD检测，任何水平异常均定义为MRD阳性。

结果

①186例AML患者中151例MRD阴性；35例MRD阳性，其中25例MRD<1%，10例MRD为1%~3%。②2年总体无病生存（DFS）率为80.0%（95% CI 68.5%~92.3%）。与MRD阴性组比较，MRD阳性组DFS率低[62.9%（95% CI 50.6%~75.2%）对88.9%（95%CI 76.6%~100.0%），P<0.001]、复发率高[11.4%（95%CI 4.1%~29.0%）对3.3%（95%CI 0.6%~20.9%），P=0.003]、非复发死亡率（NRM）高[25.7%（95%CI 8.1%~43.3%）对7.9%（95%CI 1.3%~26.5%），P=0.001]。继发性AML组DFS率低（P=0.004），NRM高（P=0.003）。③多因素分析结果显示预处理前MFC检测的MRD阳性是DFS[HR=4.565（95%CI 2.918~9.482），P<0.001]、复发[HR=5.854（95% CI 1.538~22.288），P=0.010]及非复发死亡[HR=3.379（95%CI 1.361~8.391），P=0.009]的独立危险因素。

结论

预处理前MFC监测的MRD阳性是影响allo-HSCT治疗CR₁-AML独立危险因素，MFC监测MRD可用于AML allo-HSCT的预后评估。

TGF-β1 promotes human hepatic carcinoma HepG2 cells invasion by upregulating autophagy

OBJECTIVE

To study the role of TGF-β1 in autophagy and invasion ability of human hepatic carcinoma HepG2 cells.

MATERIALS AND METHODS

Cultured HepG2 cells were treated with different concentrations of TGF-β1 for 24 h. The protein expression levels of autophagy relative marker LC3 and Beclin1 were detected by Western blot. The effect of TGF-β1 on invasion ability of HepG2 cells was detected with transwell method.

RESULTS

The results demonstrated that TGF-β1 was able to activate autophagy of HepG2 cells in a dose-dependent manner. Autophagy inhibitor 3-methyladenine (3-MA) could reverse TGF-β1 induced autophagy process. Also, TGF-β1 significantly promotes the invasion ability of HepG2 cells; however, this process could effectively reverse by autophagy inhibitor 3-MA.

CONCLUSIONS

TGF-β1 enhances HepG2 cells invasion by upregulating autophagy.

Cardiovascular research is thriving in China

Cardiovascular disease has become the leading cause of death and constitutes a serious public health issue in China. Faced with the burgeoning epidemic of cardiovascular disease and the huge burden and economic losses it causes, the Chinese government has attached the utmost importance to cardiovascular research, increasing funding to support basic and clinical studies, integrating resources and recruiting outstanding talent from overseas. The continued and growing support from the government has yielded substantial changes in terms of new discoveries, scientific publications and drug research and development within the last decade. In spite of the advances in cardiovascular research, China still faces significant challenges ahead in encouraging innovation, developing the prevention-oriented health policies and strengthening international collaboration.

Innovations in the assessment of transplant center performance: implications for quality improvement

Continuous quality improvement efforts have become a central focus of leading health care organizations. The transplant community has been a pioneer in periodic review of clinical outcomes to ensure the optimal use of limited donor organs. Through data collected from the Organ Procurement and Transplantation Network (OPTN) and analyzed by the Scientific Registry of Transplant Recipients (SRTR), transplantation professionals have intermittent access to specific, accurate and clinically relevant data that provides information to improve transplantation. Statistical process control techniques, including cumulative sum charts (CUSUM), are designed to provide continuous, real-time assessment of clinical outcomes. Through the use of currently collected data, CUSUMs can be constructed that provide risk-adjusted program-specific data to inform quality improvement programs. When retrospectively compared to currently available data reporting, the CUSUM method was found to detect clinically significant changes in center performance more rapidly, which has the potential to inform center leadership and enhance quality improvement efforts.

Kinetics of the endocytotic pathway of Low Density Lipoprotein (LDL) in human endothelial cells line under shear stress: an in vitro confocal microscopy study

We studied the effect of mechanical forces (shear stress) on the kinetics of internalization of native LDL and ox-LDL in endothelial cell line ECV304. This study was performed by using Confocal microscopy and FRET with two carbocyanine dyes, 1,1'-dioctadecyl-3,3,3',3'-tetramethylindocarbocyanine perchlorate (DiO) as the donor and 3,3'-dioctadecyloxacarbocyanine perchlorate (DiI) as the receptor. The cells were incubated with a culture medium containing either 10 microg/ml DiI-LDL or DiO-LDL in static conditions or subjected to a laminar flow under a Confocal Laser Scanning Microscope (SP2 Leica, Germany). The results showed: (1) the possibility to evaluate the kinetics of LDL endocytosis in living cells, (2) shear stress in comparison with control group more effectively enhanced LDL uptake, (3) ox-LDL (>50 microg/ml) >4 hours incubation was found to affect the cells as reflected by their detachment at low shear stress.

Role of Ca2+ in the effects of shear stress and TNF-alpha on caveolin-1 expression

The aim of this work was to study the influences of Ca2+ (medium free calcium, with BAPTA, with 100 mM Ca2+, 100 mM Ca2++10 microM ionomycin) on the expression of caveolin-1 (structural protein of caveolae) of endothelial cells (ECs) submitted to mechanical forces (shear stress) or biochemical stimulation (TNF-alpha). We found that shear stress enhanced the caveolin-1 expression. Simultaneously, the caveolin-1 expression is dependant on [Ca2+]i: [Ca2+]free medium+100 microM BAPTA<[Ca2+]free medium<[Ca2+]100 mM<[Ca2+]100 mM+10 microM ionomycin. In contrast, TNF-alpha induced a decrease of caveolin-1 in the cells, whatever the [Ca2+]i. These results suggest that there could be a synergistic effect between shear stress and Ca2+ on caveolin-1 expression but an inflammatory stimulation (TNF-alpha) induces a down regulation of caveolin-1 expression.

Optimum nitrogen use and reduced nitrogen loss for production of rice and wheat in the Yangtse Delta region

A long-term field and lysimeter experiment under different amount of fertilizer-N application was conducted to explore the optimal N application rates for a high productive rice-wheat system and less N leaching loss in the Yangtse Delta region. In this region excessive applications of N fertilizer for the rice-wheat production has resulted in reduced N recovery rates and environment pollution. Initial results of the field experiments showed that the optimal N application rate increased with the yield. On the two major paddy soils (Hydromorphic paddy soil and Gleyed paddy soil) of the region, the optimal N application rate was 225-270 kg N hm(-2) for rice and 180-225 kg N hm(-2) for wheat, separately. This has resulted in the highest number of effective ears and Spikelets per unit area, and hence high yield. Nitrogen leaching in the form of NO(3-)-N occurs mainly in the wheat-growing season and in the ponding and seedling periods of the paddy field. Its concentration in the leachate increased with the N application rate in the lysimeter experiment. When the application rate reached 225 kg N hm(-2), the concentration rose to 5.4-21.3 mgN l(-1) in the leachate during the wheat-growing season. About 60% of the leachate samples determined contained NO(3-)-N beyond the criterion (NO(3-)-N 10 mg l(-1)) for N pollution. In the field experiment, when the N application rate was in the range of 270-315 kg hm(-2), the NO(3-)-N concentration in the leachate during the wheat-growing season ranged from 1.9 to 11.0 mg l(-1). About 20% of the leachate samples reached close to, and 10% exceeded, the criterion for N pollution. Long-term accumulation of NO(3-)-N from leaching will no doubt constitute a potential risk of N contamination of the groundwater in the Yangtse Delta Region.

Caveolin-1 redistribution in human endothelial cells induced by laminar flow and cytokine

Caveolin-1 is a principal component of caveolae and is involved in signaling transduction in a number of cells. A hypothesis was proposed in this work that mechanical forces due to flow induce caveolin-1 translocation. So the changes of caveolin-1 expression and distribution in cultured endothelial cells (HUVECs) exposed to a steady laminar flow were studied. For comparing with the influence of cytokine, caveolin-1 in the cells stimulated by TNF-alpha was also investigated. Indirect immunofluorescence and double fluorescence labeling showed that in control cells, caveolin-1 was primarily localized on the cell surface, which corresponded to the peripheral distribution of F-actin, and presented some local concentrations. In the cells exposed to a laminar flow (1.0 Pa), caveolin-1 distribution showed a time-dependent variation. After 24 h of shear, the local concentration of caveolin-1 was found, in the most cells, at upstream side of cell body. Also more caveolin-1 molecules were observed in the cells. In contrast, TNF-alpha induced a decrease of caveolin-1 in cells. The redistribution of caveolin-1 seems to be correlated to F-actin organization.

Shear stress induces caveolin-1 translocation in cultured endothelial cells

Considering that vascular endothelial caveolae could be flow sensors converting mechanical stimuli into chemical signals transmitted into the cell, this work studied, in vitro, the change of caveolin-1 expression and distribution of cultured endothelial cells exposed to laminar flows. Experimental results showed that, in control cells, caveolin-1 were primarily localized on the cell surface, and presented some local concentrations. In cells exposed to laminar flows, caveolin-1 distribution showed a time-dependent variation. After 24 h of shear (1.0 Pa), the expression of caveolin-1 increased and a local caveolin-1 concentration was found, in most cells, at the upstream side of the cell body where the hydrostatic pressure and the spatial gradient of shear stress were at a maximum. As a comparison, tumor necrosis factor-a induced a decrease of caveolin-1 in the cells.

Regulation of von willebrand factor of human endothelial cells exposed to laminar flows: an in vitro study

The effect of laminar flow on the regulation of von Willebrand Factor (vWF) of cultured human umbilical vein endothelial cells (HUVECs) was studied. Confluent endothelial monolayers were exposed to shear stresses (0.2 and 1.0 Pa) from 2 to 24 h. vWF was labelled with indirect immunofluorescence method and observed with 3D fluorescence microscopy. The distribution of vWF and the cytoskeleton organization were observed simultaneously by double fluorescence labelling. More actin stress fibers and an increased release of vWF appeared in the cells exposed to flow at the same time. The qualitative and quantitative results showed that there was not only a shear-dependent regulation but also a time-dependent modification. For a short-time shear stimulation, both 0.2 Pa and 1.0 Pa shear stresses induced a release of vWF from the endothelial cells. In contrast, after 24 h exposure to 1.0 Pa shear flow, vWFs were much more in the cells than that in the cells exposed to 0.2 Pa for 24 h (p < 0.01) or that in the control cells (p < 0.05). TNF-alpha caused a decrease of vWF and Weibel-Palade bodies in the cells.

Okadaic acid-mediated induction of the c-fos gene in estrogen receptor-negative human breast carcinoma cells utilized, in part, posttranscriptional mechanisms involving adenosine-uridine-rich elements

Signal transduction via modulation of phosphorylation after selective inhibition of protein phosphatase (PP) 1 and/or PP2A appears to play a role in okadaic acid (OA)-mediated effects. Treatment of several estrogen receptor-negative human breast carcinoma (HBC) cells with 100 nM OA resulted in induction of c-fos, c-myc, and cyclin-dependent kinase inhibitor p21WAF1/CIP1 genes. Transfections of various luciferase reporter constructs in HBC cells revealed involvement of activator protein-1-dependent as well as -independent pathways in induction of the c-fos gene by OA. MDA-MB-468 HBC cells were stably transfected with plasmids expressing luciferase, chimeric luciferase- c-fos 3' untranslated region (3'UTR), or chimeric luciferase-p21WAF1/CIP 3'UTR mRNAs. Expression of chimeric luciferase-c-fos and luciferase-p21WAF1/CIP1 mRNAs was elevated by OA in several independent sublines. Actinomycin D chase experiments revealed an enhanced rate of decay of luciferase-c-fos mRNA, whereas treatment with OA caused approximately 3.5-fold enhanced stability of the chimeric luciferase-c-fos mRNA only. By transfecting different plasmids containing deletions of c-fos 3'UTR, OA-responsive sequences were mapped to an 86-nucleotide, AU-rich region. UV cross-linking experiments using HBC cell cytosolic proteins showed multiple complexes with the AU-rich region subfragments of c-fos, as well as c-myc and p21WAF1/CIP1 mRNAs. OA enhanced binding of a novel Mr approximately 75,000 protein present in the cytosolic extracts of HBC cells to the AU-rich RNA probes of all of the above three genes. Taken together, OA regulation of HBC cell gene expression involves the activator protein-1 pathway, as well as enhanced binding of a novel Mr approximately 75,000 protein to an AU-rich region of the 3'UTRs of the target genes.

Post-transcriptional regulation of the DNA damage-inducible gadd45 gene in human breast carcinoma cells exposed to a novel retinoid CD437

The biologically active synthetic retinoid CD437 (6-[3-adamantyl-4-hydroxyphenyl]-2-naphthalene, AHPN) and different human breast carcinoma (HBC) cell lines were used to examine the possible mechanism(s) of gadd45 induction. Northern blot analysis of mRNA isolated from MCF-7, MDA-MB-468 and MDA-MB-231 HBC cell lines demonstrated a progressive increase in the 1.4 kb gadd45 transcript after exposure to 1 microM CD437. Western blot analysis showed increased gadd45 protein levels in MDA-MB-468 HBC cells following exposure to CD437. CD437 increased gadd45 mRNA levels by approximately 20-fold in MDA-MB-468 cells, however, the transcriptional activity was increased approximately 2-3-fold as demonstrated by the human gadd45 promoter-luciferase reporter construct and nuclear run-off assays. Sublines of MDA-MB-468 HBC cells expressing stably integrated GADD45 cDNA fragments were obtained and CD437-dependent induction of GADD45 analyzed. We report that approximately 300 nt located in the 5"-untranslated region (5"-UTR) of gadd45 mRNA are involved in the CD437-dependent 4-fold enhanced stability of gadd45 transcripts. MDA-MB-468 cells were stably transfected with either a plasmid having a CMV promoter-driven rabbit beta-globin gene or plasmids having a CMV promoter-driven chimeric gadd45 5"-UTR-rabbit beta-globin gene, where the entire gadd45 5"-UTR (from +1 to +298) or a 45 bp subfragment of the gadd45 5"-UTR (from +10 to +55) was positioned at the 5"-end of the rabbit beta-globin gene. CD437 was found to up-regulate expression of both the chimeric gadd45 -rabbit beta-globin transcripts, suggesting that cis element(s) involved in the CD437-dependent enhanced stability of gadd45 mRNA are contained in the 45 nt of the 5"-UTR of the gadd45 mRNA.

Overexpression of bcl-2 or bcl-XL fails to inhibit apoptosis mediated by a novel retinoid

Overexpression of bcl-2 or bcl-XL has been found to inhibit the induction of apoptosis in malignant cells by a large number of agents including a wide variety of chemotherapeutic drugs. CD437 ¿6-[3-(1-adamantyl)-4 hydroxyphenyl]-2-naphthalene carboxylic acid¿ is a novel retinoid that induces apoptosis in a number of malignant cells through a unique mechanism of action. The addition of 1 microM CD437 to HL-60/NEO cells resulted in capase 3 (CPP32) activation and poly(ADP-ribose) polymerase (PARP) cleavage in 3 h whereas in bcl-2- or bcl-XL-overexpressing HL-60 cells CD437 induced CPP32 activation and PARP cleavage in 6 h. Although 50 and 300 nM CD437 were required to induce PARP cleavage in HL-60/NEO and HL-60/bcl-2, HL-60/bcl-XL cells, respectively, maximal apoptosis in both cell lines was achieved utilizing 300 nM CD437. All three cell lines, however, share identical dose-response curves in terms of their growth inhibition, suggesting that CD437-mediated inhibition of growth and induction of apoptosis represent two distinct and separable processes. In addition, CD437 induces GI arrest as well as p21WAFI/CIPI mRNA expression in these cells despite the overexpression of bcl-2 or bcl-XL. CD437 induced mitochondrial instability as indicated by cytochrome c leakage into the cytoplasm in all three cell lines. CD437 also induced growth inhibition and apoptosis of an apoptosis-resistant variant of the HL-60 cell line (HCW-2), which switched expression from bcl-2 to bcl-XL. CD437-mediated apoptosis is not accompanied by downregulation of bcl-2 or bcl-XL or upregulation of bax. The reason for the inability of bcl-2 or bcl-XL overexpression to inhibit CD437-mediated apoptosis is unclear. The ability of CD437 to initiate apoptosis in a spectrum of malignant cells without interference from bcl-2 or bcl-XL overexpression suggests that CD437 may possess significant therapeutic potential in the treatment of malignancy.