CASP1 is a target for combination therapy in pancreatic cancer

Gemcitabine (GEM) is commonly used as the first-line chemotherapeutic agent for treating pancreatic cancer (PC) patients. However, drug resistance is a major hurdle in GEM-based chemotherapy for PC. Recent studies have shown that pyroptosis, a type of programmed death, plays a significant regulatory role in cancer development and therapy. In this study, we observed an increase in the expression of Caspase-1(CASP1)/Gasdermin-D (GSDMD) in PC and found that high expression of CASP1 and GSDMD was associated with poor overall survival (OS) and progression-free survival (PFS) of PC patients. Knockdown of either CASP1 or GSDMD resulted in the inhibition of cell viability and migration in PC cells. More importantly, the knockdown of CASP1 or GSDMD enhanced GEM-induced cell death in PC cells. Interestingly, subsequent investigations demonstrated that enzymatically active CASP1 promoted GEM-induced cell death in PC cells. The activation of CASP1 by the DPP8/DPP9 inhibitor (Val-boroPro, VbP) increased GEM-induced cell death by inducing pyroptosis. These findings suggest that inhibiting CASP1 to suppress its oncogenic effects or activating it to promote cell pyroptosis both enhance the sensitivity of PC cells to GEM therapy.

Targeting NRF2 uncovered an intrinsic susceptibility of acute myeloid leukemia cells to ferroptosis

Drug resistance and poor treatment response are major obstacles to the effective treatment of acute myeloid leukemia (AML). A deeper understanding of the mechanisms regulating drug resistance and response genes in AML is therefore urgently needed. Our previous research has highlighted the important role of nuclear factor E2-related factor 2 (NRF2) in AML, where it plays a critical role in detoxifying reactive oxygen species and influencing sensitivity to chemotherapy. In this study, we identify a core set of direct NRF2 targets that are involved in ferroptosis, a novel form of cell death. Of particular interest, we find that glutathione peroxidase 4 (GPX4) is a key ferroptosis gene that is consistently upregulated in AML, and high expression of GPX4 is associated with poor prognosis for AML patients. Importantly, simultaneous inhibition of NRF2 with ML385 and GPX4 with FIN56 or RSL3 synergistically targets AML cells, triggering ferroptosis. Treatment with ML385 + FIN56/RSL3 resulted in a marked reduction in NRF2 and GPX4 expression. Furthermore, NRF2 knockdown enhanced the sensitivity of AML cells to the ferroptosis inducers. Taken together, our results suggest that combination therapy targeting both NRF2 and GPX4 may represent a promising approach for the treatment of AML.

Overexpression of CASP1 triggers acute promyelocytic leukemia cell pyroptosis and differentiation

Caspase-1 (CASP1)-mediated classical pyroptosis plays a key role in cancer development and management, however, the role of CASP1 and its regulation has not yet been documented for acute promyelocytic leukemia (APL). Here, we found that CASP1/GSDMD had lower expression in patients with APL and most other subtypes of primary de novo acute myeloid leukemia (AML) and was increased in all-trans-retinoic acid (ATRA)-treated APL cells. We showed that ATRA increases and activates CASP1 to trigger the pyroptosis and differentiation of APL cells. Mechanistically, ATRA could induce CASP1 expression via the IFNγ/STAT1 pathway in APL cells. In conclusion, ATRA-induced activation of CASP1 may serve as a suppressor in APL progression, as it triggers pyroptotic cell death and differentiation.

High expression of LOC541471, GDAP1, SOD1, and STK25 is associated with poor overall survival of patients with acute myeloid leukemia

BACKGROUND

Acute myeloid leukemia (AML) is an aggressive heterogeneous hematological malignancy with remarkably heterogeneous outcomes. This study aimed to identify potential biomarkers for AML risk stratification via analysis of gene expression profiles.

METHODS

RNA sequencing data from 167 adult AML patients in the Cancer Genome Atlas (TCGA) database were obtained for overall survival (OS) analysis, and 52 bone marrow (BM) samples from our clinical center were used for validation. Additionally, siRNA was used to investigate the role of prognostic genes in the apoptosis and proliferation of AML cells.

RESULTS

Co-expression of 103 long non-coding RNAs (lncRNAs) and mRNAs in the red module that were positively correlated with European Leukemia Network (ELN) risk stratification and age was identified by weighted gene co-expression network analysis (WGCNA). After screening by uni- and multivariate Cox regression, Kaplan-Meier survival, and protein-protein interaction analysis, four genes including the lncRNA LOC541471, GDAP1, SOD1, and STK25 were incorporated into calculating a risk score from coefficients of the multivariate Cox regression model. Notably, GDAP1 expression was the greatest contributor to OS among the four genes. Interestingly, the risk score, ELN risk stratification, and age were independent prognostic factors for AML patients, and a nomogram model constructed with these factors could illustrate and personalize the 1-, 3-, and 5-year OS rates of AML patients. The calibration and time-dependent receiver operating characteristic curves (ROCs) suggested that the nomogram had a good predictive performance. Furthermore, new risk stratification was developed for AML patients based on the nomogram model. Importantly, knockdown of LOC541471, GDPA1, SOD1, or STK25 promoted apoptosis and inhibited the proliferation of THP-1 cells compared to controls.

CONCLUSIONS

High expression of LOC541471, GDAP1, SOD1, and STK25 may be biomarkers for risk stratification of AML patients, which may provide novel insight into evaluating prognosis, monitoring progression, and designing combinational targeted therapies.

BET bromodomain inhibition rescues PD-1-mediated T-cell exhaustion in acute myeloid leukemia

Sustained expression of programmed cell death receptor-1 (PD-1) is correlated with the exhaustion of T cells, and blockade of the PD-1 pathway is an effective immunotherapeutic strategy for treating various cancers. However, response rates are limited, and many patients do not achieve durable responses. Thus, it is important to seek additional strategies that can improve anticancer immunity. Here, we report that the bromodomain and extraterminal domain (BET) inhibitor JQ1 inhibits PD-1 expression in Jurkat T cells, primary T cells, and T-cell exhaustion models. Furthermore, JQ1 dramatically impaired the expression of PD-1 and T-cell immunoglobulin mucin-domain-containing-3 (Tim-3) and promoted the secretion of cytokines in T cells from patients with acute myeloid leukemia (AML). In line with that, BET inhibitor-treated CD19-CAR T and CD123-CAR T cells have enhanced anti-leukemia potency and resistant to exhaustion. Mechanistically, BRD4 binds to the NFAT2 and PDCD1 (encoding PD-1) promoters, and NFAT2 binds to the PDCD1 and HAVCR2 (encoding Tim-3) promoters. JQ1-treated T cells showed downregulated NFAT2, PD-1, and Tim-3 expression. In addition, BET inhibitor suppressed programmed death-ligand 1 (PD-L1) expression and cell growth in AML cell lines and in primary AML cells. We also demonstrated that JQ1 treatment led to inhibition of leukemia progression, reduced T-cell PD-1/Tim-3 expression, and prolonged survival in MLL-AF9 AML mouse model and Nalm6 (B-cell acute lymphoblastic leukemia cell)-bearing mouse leukemia model. Taken together, BET inhibition improved anti-leukemia immunity by regulating PD-1/PD-L1 expression, and also directly suppressed AML cells, which provides novel insights on the multiple effects of BET inhibition for cancer therapy.

Anticancer effects of disulfiram in T-cell malignancies through NPL4-mediated ubiquitin-proteasome pathway

T-cell malignancies, including T-cell acute lymphoblastic leukemia (T-ALL) and T-cell lymphoma (TCL), are characterized by inferior treatment effects, high heterogeneity, poor prognosis, and a lack of specific therapeutic targets and drugs to improve outcome. Disulfiram (DSF) is a drug used to clinically control alcoholism that has recently been shown to be cytotoxic for multiple cancers. However, the underlying effects and mechanisms of DFS treatment in patients with T-cell malignancies are not well characterized. In this study, we report that DSF promotes apoptosis and inhibits the proliferation of malignant T-cell cell lines and primary T-ALL cells. We provide evidence that DSF exerts anticancer activity in T-cell malignancies by targeting the NPL4-mediated ubiquitin-proteasome pathway. Notably, high expression of NPL4 and 2 ubiquitin-proteasome pathway genes, anaphase-promoting complex subunit 1 (ANAPC1) and proteasome 26S subunit ubiquitin receptor, non-ATPase 2 (PSMD2), was significantly associated with unfavorable overall survival (OS) for patients with TCL and T-ALL (p < 0.05). More importantly, the weighted combination of NPL4, ANAPC1, and PSMD2 could visually display the 1-, 3-, and 5-year OS rates for patients with T-cell malignancies in a nomogram model and facilitate risk stratification. Specifically, risk stratification was an independent predictor of OS for patients with T-cell malignancies. In conclusion, DSF might induce apoptosis and inhibit the proliferation of malignant T-cells via the NPL4-mediated ubiquitin-proteasome pathway and offer a potential therapeutic option for T-cell malignancies.

MiR-204 suppresses the progression of acute myeloid leukemia through HGF/c-Met pathway

Acute myeloid leukemia (AML) was confirmed to be associated with hematopoietic insufficiency, as well as abnormal proliferation, differentiation or survival of myeloid progenitors. Multiple studies reported that microRNA-204 (miR-204) and Hepatocyte growth factor (HGF) played important roles in types of cancers. However, the potential molecular regulatory mechanism between miR-204 and HGF in AML remains to be further defined. Real-time PCR (RT-PCR) was adopted to detect the expression of miR-204 and HG. Relative protein levels were detected by western blot assay. The viability, cell cycle, apoptosis, migration, and invasion were analyzed by MTT, flow cytometry, and transwell assays. Moreover, the target relationship between miR-204 and HGF was predicted by MiRcode website and confirmed by luciferase reporter, RNA pull-down, and western blot assays. Our data suggested that miR-204 was downregulated in AML serum samples and cells. MiR-204 overexpression repressed cell proliferation, migration, invasion, and induced cell apoptosis in AML cells. HGF was upregulated in AML samples and cells, and HGF knockdown inhibited the malignancy of AML cells. In addition, HGF was directly targeted by miR-204. HGF overexpression reversed the effects of miR-204 mimic on AML cell proliferation, apoptosis, migration, and invasion. Besides, miR-204 regulated the c-Met signaling by targeting HGF, thereby regulating the downstream protein levels related to cell proliferation, apoptosis, migration, and invasion in AML cells. In conclusion, miR-204 could regulate AML progression through regulating the HGF/c-Met pathway.

Genetic variant spectrum in 265 Chinese patients with hemophagocytic lymphohistiocytosis: Molecular analyses of PRF1, UNC13D, STX11, STXBP2, SH2D1A, and XIAP

Hemophagocytic lymphohistiocytosis (HLH) is a rare life-threatening hyperinflammatory disease. This study aimed to investigate the frequencies and distributions of inherited variants in PRF1, UNC13D, STX11, STXBP2, SH2D1A, and XIAP genes in Chinese patients with HLH. A total of 265 patients diagnosed with HLH from January, 2010 to December, 2016 were recruited and analyzed for the 6 genes. Genetic variants were observed in 87 (32.83%) patients. 36 (13.58%) exhibited variants in UNC13D, 18 (6.79%) exhibited PRF1 variants, 10 (3.77%) had variants in XIAP, 9 (3.40%) exhibited variants in STXBP2, 6 (2.26%) carried variants in SH2D1A, 1 (0.38%) had STX11 variant, and 7 (2.64%) exhibited digenic variants. Monoallelic variants were the most common, which accounted for 49.43% of all cases with variants. All variants were confirmed to be germline-derived. The present study describes a distinct variant spectrum in Chinese patients with HLH, whereby UNC13D is the most frequently mutated gene with missense variants that are the most common molecular defects. The variant profile of Chinese HLH patients is quite different from that of Western cohorts but similar to that of Korean patients, yet showing its own uniqueness. This racial difference shows the role of genetic background in the occurrence of HLH.

Relationship between environmental conditions, TRI5 gene expression and deoxynivalenol production in stored Lentinula edodes infected with Fusarium graminearum

This study made the first attempt to relate the production of deoxynivalenol (DON) to the expression of TRI5 gene in Fusarium graminearum as a function of interacting environmental factors (water activity (aw) (0.95-0.98), temperature (20-30 °C) and incubation time (7 day-28 day)), so as to investigate its production mechanisms in Lentinula edodes. Changes in temperature, water activity and incubation time could significantly (P<0.01) affect DON production and TRI5 gene expression. The highest DON concentration (793.5±27.4 μg/kg) and TRI5 gene expression (2−ΔΔCt=38.8±4.8) were observed when the cultures were incubated at 20 °C and 0.98 aw for 21 days. Multi-regression analysis was performed and nonlinear models based on polynomial equations were established to uncover the individual effects of temperature, water activity and incubation time as well as their interactions on DON production and TRI5 gene expression. The established model was further used to develop contour maps to predict the DON production and TRI5 gene expression in relation to storage conditions in L. edodes. Highly significant positive correlation between DON production and fold TRI5 gene expression (R=0.5534, P<0.0001) was observed in this commodity. The production mechanisms of DON in L. edodes revealed in the present study will be beneficial for developing more effective targeted control strategies.

SEGMENTATION OF ORGANS AT RISK IN THORACIC CT IMAGES USING A SHARPMASK ARCHITECTURE AND CONDITIONAL RANDOM FIELDS

Cancer is one of the leading causes of death worldwide. Radiotherapy is a standard treatment for this condition and the first step of the radiotherapy process is to identify the target volumes to be targeted and the healthy organs at risk (OAR) to be protected. Unlike previous methods for automatic segmentation of OAR that typically use local information and individually segment each OAR, in this paper, we propose a deep learning framework for the joint segmentation of OAR in CT images of the thorax, specifically the heart, esophagus, trachea and the aorta. Making use of Fully Convolutional Networks (FCN), we present several extensions that improve the performance, including a new architecture that allows to use low level features with high level information, effectively combining local and global information for improving the localization accuracy. Finally, by using Conditional Random Fields (specifically the CRF as Recurrent Neural Network model), we are able to account for relationships between the organs to further improve the segmentation results. Experiments demonstrate competitive performance on a dataset of 30 CT scans.

Occurrence and exposure assessment of multiple mycotoxins in dried fruits based on liquid chromatography-tandem mass spectrometry

A reliable analytical method based on liquid chromatography-tandem mass spectrometry was developed for simultaneous determination of aflatoxin B1 (AFB1), aflatoxin B2 (AFB2), aflatoxin G1, aflatoxin G2, ochratoxin A (OTA), deoxynivalenol, T-2 and HT-2 toxin, and zearalenone (ZEA) in various dried fruits. A simple one-step sample extraction without using clean-up cartridges made the established method less labour consuming and less expensive, while optimisation of the several important MS/MS parameters, i.e. the scan time and run segments, ensured its sensitivity and selectivity. After careful validation of the method by determining the linearity (R2>0.99), recovery (77.8-115.9%), precision (relative standard deviation ≤19.5%) and sensitivity (limits of quantification in the range of 0.1-10 μg/kg), a survey of 125 dried fruit samples including 25 pistachios, 28 dried longans, 32 raisins and 40 dried dates randomly collected from different markets in Shanghai, China, was performed. Results revealed that 32.0% of samples were contaminated with different mycotoxins, among which, OTA was the most frequent contaminant with the incidence of 29.6% attaining the concentration levels in the range of 0.4-212.6 μg/kg. ZEA was positively found in 2 pistachio samples with the concentrations of 84.9 μg/kg and 426.9 μg/kg. Trace amounts of AFB1 (0.8 μg/kg) and AFB2 (0.2 μg/kg) were also observed in one pistachio sample and one dried longan sample, respectively. To the best of our knowledge, this is the first report to reveal the real situations of mycotoxin contaminations in various dried fruits in China.

HLA-A*11:188: a new allele identified by sequence-based typing in a Chinese blood donor

A novel allele HLA-A*11:188 differs from HLA-A*11:01:01 by a single mutation at position 439 in exon 3.

Identification of the novel HLA-C*03:240 allele

HLA-C*03:240 differs from HLA-C*03:42 by a single nucleotide substitution that results in a missense mutation Tyr 99 Cys (TAT to TGT).

Comparison of long-term and short-term administration of itraconazole for primary antifungal prophylaxis in recipients of allogeneic hematopoietic stem cell transplantation: a multicenter, randomized, open-label trial

BACKGROUND

The optimal agents and duration of primary antifungal prophylaxis in recipients of allogeneic hematopoietic stem cell transplantation (allo-HSCT) remain a matter of discussion.

OBJECTIVE

Our objective was to compare the efficacy and safety of long-term and short-term administration of itraconazole (ITCZ) for primary antifungal prophylaxis in allo-HSCT recipients.

METHODS

This multicenter, randomized, open-label pilot study was performed in 4 transplant centers in China. Recipients of allo-HSCT without a history of invasive fungal disease (IFD) were randomly assigned to the long-term or the short-term arm. Randomization was carried out by a center computer system. Intravenous ITCZ was given to the patients in both study arms with a loading dose of 400 mg/day for 2 days followed by 200 mg/day until day +14 or when the white blood cell count was >1.0 × 10(9) /L, and then switched to oral ITCZ solution; prophylaxis was continued until day +30 post transplantation in the short-term arm or until day +90 in the long-term arm. The trough serum concentrations of ITCZ also were measured. The primary study endpoint was the incidence of IFD (proven, probable, and possible) within day +90 post transplantation.

RESULTS

A total of 128 recipients were enrolled in this study; 59 of them were randomized to the long-term arm and 62 were randomized to the short-term arm, forming the modified intent-to-treat (mITT) set. The incidence of IFD within day +90, the primary endpoint, was not significantly different between the 2 arms for the mITT set (6.78% in the long-term arm vs. 6.45% in the short-term arm, P = 0.94), or for the per-protocol set (6.90% in the long-term arm vs. 6.67% in the short-term arm, P = 0.96). From day +30 to day +90, the incidence of IFD was 0% and 6.45%, respectively, in the patients with long-term and short-term prophylaxis for the mITT set (P = 0.11). The mean trough serum concentrations of ITCZ was maintained at >500 ng/mL throughout administration. The incidences of withdrawal because of drug-related adverse events in patients with long-term and short-term prophylaxis were 6.78% and 0%, respectively (P = 0.05).

CONCLUSIONS

Long-term and short-term administration of ITCZ both seemed effective in preventing IFD in recipients of allo-HSCT. Further study with large sample size should be performed to evaluate this result. ITCZ shows the same pharmacokinetics in recipients of allo-HSCT as in non-recipients.

Radiosensitivity of human prostate cancer cells can be modulated by inhibition of 12-lipoxygenase

Nearly 30% of prostate cancer (PCa) patients treated with potentially curative doses relapse at the sites of irradiation. How some tumor cells acquire radioresistance is poorly understood. The platelet-type 12-lipoxygenases (12-LOX)-mediated arachidonic acid metabolism is important in PCa progression. Here we show that 12-LOX confers radioresistance upon PCa cells. Treatment with 12-LOX inhibitors baicalein or BMD122 sensitizes PCa cells to radiation, without radiosensitizing normal cells. 12-LOX inhibitors and radiation, when combined, have super additive or synergistic inhibitory effects on the colony formation of both androgen-dependent LNCaP and androgen-independent PC-3 PCa cells. In vivo, the combination therapy significantly reduced tumor growth.

Short-chain fatty acids induced autophagy serves as an adaptive strategy for retarding mitochondria-mediated apoptotic cell death

Short-chain fatty acids (SCFAs) are the major by-products of bacterial fermentation of undigested dietary fibers in the large intestine. SCFAs, mostly propionate and butyrate, inhibit proliferation and induce apoptosis in colon cancer cells, but clinical trials had mixed results regarding the anti-tumor activities of SCFAs. Herein we demonstrate that propionate and butyrate induced autophagy in human colon cancer cells to dampen apoptosis whereas inhibition of autophagy potentiated SCFA induced apoptosis. Colon cancer cells, after propionate treatment, exhibited extensive characteristics of autophagic proteolysis: increased LC3-I to LC3-II conversion, acidic vesicular organelle development, and reduced p62/SQSTM1 expression. Propionate-induced autophagy was associated with decreased mTOR activity and enhanced AMP kinase activity. The elevated AMPKα phosphorylation was associated with cellular ATP depletion and overproduction of reactive oxygen species due to mitochondrial dysfunction involving the induction of MPT and loss of Δψ. In this context, mitochondria biogenesis was initiated to recover cellular energy homeostasis. Importantly, when autophagy was prevented either pharmacologically (3-MA or chloroquine) or genetically (knockdown of ATG5 or ATG7), the colon cancer cells became sensitized toward propionate-induced apoptosis through activation of caspase-7 and caspase-3. The observations indicate that propionate-triggered autophagy serves as an adaptive strategy for retarding mitochondria-mediated apoptotic cell death, whereas application of an autophagy inhibitor (Chloroquine) is expected to enhance the therapeutic efficacy of SCFAs in inducing colon tumor cell apoptosis.

Role of eicosanoids in prostate cancer progression

Metabolism of arachidonic acid through cyclooxygenase, lipoxygenase, or P450 epoxygenase pathways leads to the formation of various bioactive eicosanoids. In this review, we discuss alterations in expression pattern of eicosanoid-generating enzymes found during prostate tumor progression and expound upon their involvement in tumor cell proliferation, apoptosis, motility, and tumor angiogenesis. The expression of cyclooxygenase-2, 12-lipoxygenase, and 15-lipoxygenase-1 are up-regulated during prostate cancer progression. It has been demonstrated that inhibitors of cyclooxygenase-2, 5-lipoxygenase and 12-lipoxygenase cause tumor cell apoptosis, reduce tumor cell motility and invasiveness, or decrease tumor angiogenesis and growth. The eicosanoid product of 12-lipoxygenase, 12(S)-hydroeicosatetraenoic acid, is found to activate Erkl/2 kinases in LNCaP cells and PKCalpha in rat prostate AT2.1 tumor cells. Overexpression of 12-lipoxygenase and 15-lipoxygenase-1 in prostate cancer cells stimulate prostate tumor angiogenesis and growth, suggesting a facilitative role for 12-lipoxygenase and 15-lipoxygenase-1 in prostate tumor progression. The expression of 15-lipoxygenase-2 is found frequently to be lost during the initiation and progression of prostate tumors. 15(S)-hydroxyeicosatetraenoic acid, the product of 15-lipoxygenase-2, inhibits proliferation and causes apoptosis in human prostate cancer cells, suggesting an inhibitory role for 15-lipoxygenase-2 in prostate tumor progression. The regulation of prostate cancer progression by eicosanoids, in either positive or negative ways, provides an exciting possibility for management of this disease.

Cyclooxygenase, lipoxygenase and tumor angiogenesis

Arachidonic acid metabolism through cyclooxygenase (COX) and lipoxygenase (LOX) pathways generates various biologically active lipids that play important roles in inflammation, thrombosis and tumor progression. Angiogenesis, the formation of new capillary vessels from preexisting ones, underpins a number of physiological processes and participates in the development of several pathological conditions such as arthritis, cancer and various eye diseases. The formation of new capillary vessels is a multistep process that involves endothelial cell proliferation, migration and tube formation. In the present review, we survey the literature on the regulation of angiogenesis by arachidonate metabolites, especially those from the COX and 12-LOX pathways in the context of tumor growth, and put forward some unanswered but important questions for future studies.

[Changes in the activity of platelet L-arginine/nitric oxide pathway in hypercholesterolemia patients]

OBJECTIVE

To investigate the changes of the platelet L-arginine (L-Arg)/nitric oxide (NO) pathway in hypercholesterolemia patients.

METHODS

The platelet NO production in 21 hypercholesterolemia (HC) patients and 26 normal individuals was assayed by spectrum, the NOS activity and the transportation of L-Arg were determined by (3)H-labelled L-Arg.

RESULTS

The NO production in hypercholesterolemic platelets [(24.06 +/- 3.70) nmol/10(8) platelets] was decreased significantly as compared with normal controls [(28.39 +/- 4.45) nmol/10(8) platelets] (P < 0.01), and so did the NOS activity [(1.46 +/- 0.47) pmol/10(8) platelets] vs (1.81 +/- 0.50) pmol/10(8) platelets]. The transportation of L-Arg by hypercholesterolemia platelets also decreased significantly than that by normal controls. The Vmax in the former [(46.84 +/- 3.39) pmol x (10(7) platelets)(-1) x min(-1)] was significantly lower than that in the latter [(53.89 +/- 3.45) pmol x (10(7) platelets)(-1) x min(-1)]. There was no difference between the two groups in K(d) (P > 0.05).

CONCLUSIONS

The activity of the L-arg/NO pathway in hypercholesterolemia platelets is decreased significantly as compared with normal controls, implying that it is probably one of the reasons for the hyperactivity of hypercholesterolemia platelets.

[Influence of pravastatin on expression of platelet CD(62P) and CD(41) in patients with hypercholesterolemia in vitro and in vivo]

OBJECTIVE

To study in vitro and in vivo effect of hypercholesterolemia (HC) on expression of platelet CD(62P) and CD(41) and their changes after treatment with pravastatin.

METHODS

Twenty patients with HC were given 10 - 20 mg/d pravastatin orally for 4 - 8 weeks. Changes of blood cholesterol and expression of platelet CD(62P) and CD(41) were detected by flow cytometry.

RESULTS

After 4 and 8 weeks' treatment, blood cholesterol level and platelet aggregation function decreased. The expression of CD(62P) average fluorescence intensity decreased from 31.8 +/- 7.8 to 27.2 +/- 6.9 and 26.8 +/- 4.9; CD(62P) (%) from (31.3 +/- 9.3)% to (26.4 +/- 7.4)% and (25.3 +/- 9.1)% (P < 0.05); CD(41) from 483.2 +/- 263.9 to 348.1 +/- 192.4 and 306.8 +/- 128.0 (P < 0.05), respectively. Similar results were obtained in vitro study.

CONCLUSION

Improvement of platelet function and expressions of CD(62P) and CD(41) in HC patients after prevastatin treatment may be resulted from enhancing arteriosclerosis regression. It suggested from the in vitro result that pravastatin might play a direct effect on platelet function.

Eicosanoid 12(S)-HETE activates phosphatidylinositol 3-kinase

The arachidonic acid metabolite of 12 lipoxygenase, 12(S)-hydroxyeicosatetraenoic acid (12(S)-HETE) promotes metastatic behavior of tumor cells. In this study we set out to identify 12(S)-HETE signaling pathways, and their contribution to cellular functions in A431 epidermoid carcinoma. (1) 12(S)-HETE stimulated phosphotyrosine associated PI3 kinase activity. (2) 12(S)-HETE stimulated ERK1/2 in a PI3 kinase dependent manner. (3) PI3 kinase affected the 12(S)-HETE stimulated Raf/MEK/ERK cascade at the level of MEK. (4) 12(S)-HETE stimulated ERK1/2 via PKCzeta. (5) 12(S)-HETE stimulated cell migration on laminin, which was eliminated by PI3 kinase and cPKC inhibitors, but it was unaffected by inhibition of ERK1/2.

Expression, subcellular localization and putative function of platelet-type 12-lipoxygenase in human prostate cancer cell lines of different metastatic potential

The involvement of 12-lipoxygenase (12-LOX) expression and function in tumor metastasis has been demonstrated in several murine tumor cell lines. In addition, 12-LOX expression was detected in human prostatic tumors and correlated to the clinical stage of disease. Here we provide data that human prostate cancer cell lines express the platelet-type isoform of 12-LOX at both the mRNA and protein levels, and immunohistochemistry revealed 12-LOX expression in human prostate tumors. The enzyme was localized to the plasma membrane, cytoplasmic organelles and nucleus in non-metastatic cells (PC-3 nm) and to the cytoskeleton and nucleus in metastatic cells (DU-145). After orthotopic/intraprostatic injection of tumor cells into SCID mice, the metastatic prostate carcinoma cells (DU-145) expressed 12-LOX at a significantly higher level compared with the non-metastatic counterparts, PC-3nm. The functional involvement of 12-LOX in the metastatic process was demonstrated when DU-145 cells were pretreated in vitro with the 12-LOX inhibitors N-benzyl-N-hydroxy-5-phenylpentamide (BHPP) or baicalein, the use of which significantly inhibited lung colonization. These data suggest a potential involvement of 12-LOX in the progression of human prostate cancer.

Expression, subcellular localization and putative function of platelet-type 12-lipoxygenase in human prostate cancer cell lines of different metastatic potential

The involvement of 12-lipoxygenase (12-LOX) expression and function in tumor metastasis has been demonstrated in several murine tumor cell lines. In addition, 12-LOX expression was detected in human prostatic tumors and correlated to the clinical stage of disease. Here we provide data that human prostate cancer cell lines express the platelet-type isoform of 12-LOX at both the mRNA and protein levels, and immunohistochemistry revealed 12-LOX expression in human prostate tumors. The enzyme was localized to the plasma membrane, cytoplasmic organelles and nucleus in non-metastatic cells (PC-3 nm) and to the cytoskeleton and nucleus in metastatic cells (DU-145). After orthotopic/intraprostatic injection of tumor cells into SCID mice, the metastatic prostate carcinoma cells (DU-145) expressed 12-LOX at a significantly higher level compared with the non-metastatic counterparts, PC-3nm. The functional involvement of 12-LOX in the metastatic process was demonstrated when DU-145 cells were pretreated in vitro with the 12-LOX inhibitors N-benzyl-N-hydroxy-5-phenylpentamide (BHPP) or baicalein, the use of which significantly inhibited lung colonization. These data suggest a potential involvement of 12-LOX in the progression of human prostate cancer.

Eicosanoid regulation of angiogenesis in human prostate carcinoma and its therapeutic implications

Cancer of the prostate is the most commonly diagnosed cancer in America. There are several lines of evidence implicating the involvement of arachidonate 12-lipoxygenase, an enzyme metabolizing arachidonic acid to form 12(S)-hydroxyeicosatetraenoic acid (HETE), in prostate cancer progression. First, as prostate cancer reaches a more advanced stage, the level of 12-lipoxygenase expression is increased. Second, overexpression of 12-lipoxygenase in human prostate cancer cells stimulates angiogenesis and tumor growth. Third, an inhibitor of 12-lipoxygenase has been found effective against metastatic prostate tumor growth, and the inhibition of 12-lipoxygenase is related with the reduction of tumor angiogenesis. Collectively, these studies suggest that 12-lipoxygenase regulates tumor angiogenesis in prostate cancer and that inhibition of 12-lipoxygenase is a novel therapeutic approach for the treatment of prostate cancers.

Eicosanoid regulation of angiogenesis: role of endothelial arachidonate 12-lipoxygenase

Angiogenesis, the formation of new capillaries from preexisting blood vessels, is a multistep, highly orchestrated process involving vessel sprouting, endothelial cell migration, proliferation, tube differentiation, and survival. Eicosanoids, arachidonic acid (AA)-derived metabolites, have potent biologic activities on vascular endothelial cells. Endothelial cells can synthesize various eicosanoids, including the 12-lipoxygenase (LOX) product 12(S)-hydroxyeicosatetraenoic acid (HETE). Here we demonstrate that endogenous 12-LOX is involved in endothelial cell angiogenic responses. First, the 12-LOX inhibitor, N-benzyl-N-hydroxy-5-phenylpentanamide (BHPP), reduced endothelial cell proliferation stimulated either by basic fibroblast growth factor (bFGF) or by vascular endothelial growth factor (VEGF). Second, 12-LOX inhibitors blocked VEGF-induced endothelial cell migration, and this blockage could be partially reversed by the addition of 12(S)-HETE. Third, pretreatment of an angiogenic endothelial cell line, RV-ECT, with BHPP significantly inhibited the formation of tubelike/cordlike structures within Matrigel. Fourth, overexpression of 12-LOX in the CD4 endothelial cell line significantly stimulated cell migration and tube differentiation. In agreement with the critical role of 12-LOX in endothelial cell angiogenic responses in vitro, the 12-LOX inhibitor BHPP significantly reduced bFGF-induced angiogenesis in vivo using a Matrigel implantation bioassay. These findings demonstrate that AA metabolism in endothelial cells, especially the 12-LOX pathway, plays a critical role in angiogenesis.

Identification of 12-lipoxygenase interaction with cellular proteins by yeast two-hybrid screening

The platelet isoform of 12-lipoxygenase (12-LOX) is expressed in a variety of human tumors. 12-LOX metabolizes arachidonic acid to 12(S)-hydroxyeicosateraenoic acid (12(S)-HETE), which induces a number of cellular responses associated with tumor progression and metastasis. Little is known about 12-LOX regulation and no direct regulators of 12-LOX activity have been identified. To identify potential regulators of 12-LOX, we isolated cDNAs encoding 12-LOX interacting proteins using the yeast two-hybrid system. We screened a yeast two-hybrid interaction library from human epidermoid carcinoma A431 cells and identified four cellular proteins that interact specifically with 12-LOX. We identified type II keratin 5, lamin A, the cytoplasmic domain of integrin beta4 subunit and a phosphoprotein C8FW as 12-LOX interacting proteins. Here, we demonstrated that keratin 5, a 58 kD protein required for formation of 8 nm intermediate filaments, binds to 12-LOX in human tumor cells and may contribute to the regulated trafficking of 12-LOX. We also showed that lamin A binds 12-LOX in human tumor cells. These proteins provide the first candidate regulators of 12-LOX.

Thromboxane A(2) regulation of endothelial cell migration, angiogenesis, and tumor metastasis

Prostaglandin endoperoxide H synthases and their arachidonate products have been implicated in modulating angiogenesis during tumor growth and chronic inflammation. Here we report the involvement of thromboxane A(2), a downstream metabolite of prostaglandin H synthase, in angiogenesis. A TXA(2) mimetic, U46619, stimulated endothelial cell migration. Angiogenic basic fibroblast growth factor (bFGF) or vascular endothelial growth factor (VEGF) increased TXA(2) synthesis in endothelial cells three- to fivefold. Inhibition of TXA(2) synthesis with furegrelate or CI reduced HUVEC migration stimulated by VEGF or bFGF. A TXA(2) receptor antagonist, SQ29,548, inhibited VEGF- or bFGF-stimulated endothelial cell migration. In vivo, CI inhibited bFGF-induced angiogenesis. Finally, development of lung metastasis in C57Bl/6J mice intravenously injected with Lewis lung carcinoma or B16a cells was significantly inhibited by thromboxane synthase inhibitors, CI or furegrelate sodium. Our data demonstrate the involvement of TXA(2) in angiogenesis and development of tumor metastasis.

The beta4 integrin subunit rescues A431 cells from apoptosis through a PI3K/Akt kinase signaling pathway

To study whether alpha6beta4 integrin regulates apoptosis, human A431 cells were plated on bacteria plates in the presence or absence of mAb beta4. In the absence of mAb beta4, A431 cells demonstrated morphological characteristics of apoptosis by 24 h and most cells died by 48 h. In contrast, in the presence of mAb beta4, cells remained viable, and at the end of 48 h, 70-80% of cells survived. Treatment of A431 cells with mAb beta4 resulted in tyrosine phosphorylation of the p85 subunit of PI3 kinase; PI3 kinase activity increased within 15 min and peaked at 60 min. Stimulation of beta4 in A431 cells resulted in a time-dependent phosphorylation of Akt with a concomitant and parallel phosphorylation of Bad. Inactivation of PI3 kinase with inhibitors blocked the anti-apoptotic effect induced by mAb beta4. These are the first results to suggest that ligation of alpha6beta4 integrin protects cells from apoptosis through a PI3K/Akt kinase signaling pathway.

Platelet-type 12-lipoxygenase in a human prostate carcinoma stimulates angiogenesis and tumor growth

Previously, we found a positive correlation between the expression of platelet-type 12-lipoxygenase (12-LOX) and the progression of human prostate adenocarcinoma (PCa; Gao et al., Urology, 46: 227-237, 1995). To determine the role of 12-LOX in PCa progression, we generated stable 12-LOX-transfected PC3 cells, which synthesize high levels of 12-LOX protein and 12(S)-hydroxyeicosatetraenoic acid metabolite. In vitro, 12-LOX-transfected PC3 cells demonstrated a proliferation rate similar to neo controls. However, following s.c. injection into athymic nude mice, 12-LOX-transfected PC3 cells formed larger tumors than did the controls. Decreased necrosis and increased vascularization were observed in the tumors from 12-LOX-transfected PC3 cells. Both endothelial cell migration and Matrigel implantation assays indicate that 12-LOX-transfected PC3 cells were more angiogenic than their neo controls. These data indicate that 12-LOX stimulates human PCa tumor growth by a novel angiogenic mechanism.

Inhibition of terminal differentiation and matrix calcification in cultured avian growth plate chondrocytes by Rous sarcoma virus transformation

Endochondral bone formation involves the progression of epiphyseal growth plate chondrocytes through a sequence of developmental stages which include proliferation, differentiation, hypertrophy, and matrix calcification. To study this highly coordinated process, we infected growth plate chondrocytes with Rous sarcoma virus (RSV) and studied the effects of RSV transformation on cell proliferation, differentiation, matrix synthesis, and mineralization. The RSV-transformed chondrocytes exhibited a distinct bipolar, fibroblast-like morphology, while the mock-infected chondrocytes had a typical polygonal morphology. The RSV-transformed chondrocytes actively synthesized extracellular matrix proteins consisting mainly of type I collagen and fibronectin. RSV-transformed cells produced much less type X collagen than was produced by mock-transformed cells. There also was a significant reduction of proteoglycan levels secreted in both the cell-matrix layer and culture media from RSV-transformed chondrocytes. RSV-transformed chondrocytes expressed two- to- threefold more matrix metalloproteinase, while expressing only one-half to one-third of the alkaline phosphatase activity of mock infected cells. Finally, RSV-transformed chondrocytes failed to calcify the extracellular matrix, while mock-transformed cells deposited high levels of calcium and phosphate into their extracellular matrix. These results collectively indicate that RSV transformation disrupts the preprogrammed differentiation pattern of growth plate chondrocytes and inhibit chondrocyte terminal differentiation and mineralization. They also suggest that the expression of extracellular matrix proteins, type II and type X collagens, and the cartilage proteoglycans are important for chondrocyte terminal differentiation and matrix calcification.

Induction and characterization of metallothionein in chicken epiphyseal growth plate cartilage chondrocytes

Following exposure to cadmium or zinc, chickens were sacrificed and the liver, kidney, and bone epiphyseal growth plates harvested. When cytosolic extracts of the growth plate cartilage were fractionated by gel filtration chromatography, a protein with high metal-binding capacity and low ultraviolet (UV) absorbance eluted in the same position as liver metallothionein (MT) and a MT standard. Cd or Zn treatment resulted in a 25-fold or 5-fold induction in growth plate MT, respectively. In liver the greatest level of MT induction was seen with short-term Cd exposures. In contrast, MT levels in the growth plate increased as the duration of Cd exposure increased. Induction of MT in growth plate chondrocyte cell cultures was observed for media Cd concentrations of > or = 0.1 microM and Zn concentrations of > or = 100 microM. Basal and inducible levels of MT declined through the culture period and were lowest in the terminally differentiated mineralized late stages of the culture. Alkaline phosphatase activity was also lowest in the late-stage cultures, while total cellular protein increased throughout the culture period. Treatment of chondrocytes with Zn prior to Cd exposure resulted in a protective induction of MT. Pre-treatment of chondrocytes with dexamethasone resulted in suppressed synthesis of MT upon Cd exposure and greater Cd toxicity. Both Cd and Zn resulted in significantly increased levels of MT mRNA in chondrocyte cell cultures. Dexamethasone treatment resulted in an approximate 2- to 3-fold increase in MT mRNA. This is contrary to the finding that MT protein levels were decreased by dexamethasone. The findings suggest that an increased rate of MT degradation in dexamethasone-treated and late-stage chondrocyte cultures may be associated with the terminally differentiated phenotype.

Retinoic acid treatment elevates matrix metalloproteinase-2 protein and mRNA levels in avian growth plate chondrocyte cultures

Matrix metalloproteinases (MMPs) play a crucial role in tissue remodeling. In growth plate (GP) cartilage, extensive remodeling occurs at the calcification front. To study the potential involvement of MMPs in retinoic acid (RA) regulation of skeletal development, we studied the effect of all-trans-RA on MMPs levels in mineralizing chicken epiphyseal chondrocyte primary cultures. When treated for 4 day periods on days 10 and 17, RA increased levels of an approximately 70 kDa gelatinase activity. The N-terminal sequence of the first 20 amino acid residues of the purified enzyme was identical to that deduced from chicken MMP-2 cDNA. Time-course studies indicated that RA elevated MMP-2 activity levels in the cultures within 16 h. This increase was inhibited by cycloheximide and was enhanced by forskolin. The increase in MMP-2 activity induced by RA was accompanied by an increase in MMP-2 mRNA levels and was abolished by treatment with cycloheximide. This upregulation of MMP levels by RA in GP chondrocytes is consistent with its effects on osteoblasts and osteosarcoma cells and opposite its inhibitory effects on fibroblasts and endothelial cells. It may well be related to the breakdown of the extracellular matrix in the GP and would be governed by the availability of RA at the calcification front where extensive vascularization also occurs.

Retinoic acid stimulates matrix calcification and initiates type I collagen synthesis in primary cultures of avian weight-bearing growth plate chondrocytes

The effect of retinoic acid (RA) on primary cultures of growth plate chondrocytes obtained from weight-bearing joints was examined, Chondrocytes were isolated from the tibial epiphysis of 6- to 8-week-old broiler-strain chickens and cultured in either serum-containing or serum-free media. RA was administered at low levels either transiently or continuously after the cells had become established in culture. Effects of RA on cellular protein levels, alkaline phosphatase (AP) activity, synthesis of proteoglycan (PG), matrix calcification, cellular morphology, synthesis of tissue-specific types of collagen, and level of matrix metalloproteinase (MMP) activity were explored. RA treatment generally increased AP activity and stimulated mineral deposition, especially if present continuously. RA also caused a shift in cell morphology from spherical/polygonal to spindle-like. This occurred in conjunction with a change in the type of collagen synthesized: type X and II collagens were decreased, while synthesis of type I collagen was increased. There was also a marked increase in the activity of MMP. Contrasting effects of continuous RA treatment on cellular protein levels were seen: they were enhanced in serum-containing media, but decreased in serum-free HL-1 media. Levels of RA as low as 10 nM significantly inhibited PG synthesis and caused depletion in the levels of PG in the medium and cell-matrix layer. Thus, in these appendicular chondrocytes, RA suppressed chondrocytic (PG, cartilage-specific collagens) and enhanced osteoblastic phenotype (cell morphology, type I collagen, alkaline phosphatase, and mineralization).

Defect in formation of functional matrix vesicles by growth plate chondrocytes in avian tibial dyschondroplasia: evidence of defective tissue vascularization

Avian tibial dyschondroplasia (ATD), a disease characterized by an almost total lack of mineralization in affected areas of growth plate cartilage, may involve defective matrix vesicle (MV) mineralization. To explore the biochemical defect in ATD, both normal and diseased tissue were analyzed for the amount of isolatable MVs, their chemical composition, and their ability to induce mineral formation. We found significantly fewer MVs in ATD tissue, and in contrast to normal MVs, which rapidly mineralized when incubated in synthetic cartilage lymph, those isolated from ATD lesions induced only limited mineralization even after prolonged incubation. Analysis by detergent extraction revealed a nearly dysfunctional nucleational core in ATD MVs. Thus, in ATD tissue, there is a defect in the formation of MVs, and those that form are nearly inactive. There were also alterations in the lipid-dependent Ca2+(-)binding proteins (annexins) in ATD MVs. There were lower levels of annexins II and VI in endogenously produced collagenase-released matrix vesicles (CRMVs), but not in matrix vesicle-enriched microsomes (MVEMs) produced by tissue homogenization. These findings indicate that there is insufficient Ca2+ in ATD cells to enable incorporation of the annexins into MVs. Finally, there was evidence of phospholipid breakdown in ATD MVs, as well as in ATD tissue generally. This indicated that the ATD lesions were becoming necrotic. Taken together, these findings indicate that there is a defect in tissue vascularization such that the supply of mineral ions and nutrients to ATD cartilage is inadequate to support normal MV formation and subsequent mineralization.

[Research on the different blood types umbilical cord blood hematopoietic progenitors mixed culture in vitro]

Using single layer agar culture method, we make a study on culture of human hematopoietic progenitor cell from umbilical cord blood. The result showed the mean value of the granulocyte macrophage progenitor cells (CFU-GM) from twenty neonates cord blood was 95.6 +/- 36.5/10(6) MNC. We compared the mixed culture of two different blood types neonates cord blood hematopoietic progenitors with single sample and found little difference between them in number and growth characteristics. This may provide a theoretical basis for clinical transplantation of mixed human cord progenitor cells.

Optoelectronic implementation of a compression-attraction-sphere associative memory using an optical spatial pattern-encoding method

A compression-attraction-sphere associative-memory model is proposed. An optoelectronic implementation of its inner-product architecture using an optical spatial pattern-encoding method is demonstrated bycomputer simulations and preliminary experiments.