Integrative analyses of RNA-seq and ChIP-seq Reveal MITF as a Target Gene of TFPI-2 in MDA231 Cells.

Breast cancer is the most prevalent cancer in female patients worldwide. Tissue factor pathway inhibitor 2 (TFPI-2) is identified as an important tumor suppressor in various cancers. Recent studies have shown that TFPI-2 translocates into the nucleus, where it modulates the transcription of the matrix metalloproteinase-2 (MMP-2) gene. However, its biological role and molecular mechanisms in the progression of breast cancer remain unclear. In this study, we identified 5125 differentially expressed genes (DEGs) from RNA sequencing (RNA-seq) in TFPI-2-overexpressing MDA231 cells compared with control cells. Gene ontology and Kyoto encyclopedia of genes and genomes (KEGG) analysis shown that cell cycle, cell differentiation, proteoglycans in cancer, and pathways associated with cancer were highly enriched in downregulated DEGs. Integration of the RNA-seq and ChIP-sequencing (ChIP-seq) data identified 73 genes directly controlled by TFPI-2 in MDA231 cells. Among them, melanocyte inducing transcription factor (MITF) gene expression was repressed by TFPI-2, which was further verified by a luciferase reporter assay and ChIP-quantitative PCR. Our study provides evidence of a novel role of TFPI-2 in human breast cancer involving targeting of the MITF.

Deletion of IL-27p28 induces CD8 T cell immunity against colorectal tumorigenesis.

Colorectal cancer (CRC) is a leading cause of cancer-related deaths worldwide, characterized by molecular and clinical heterogeneity. Interleukin (IL)-27, a heterodimeric cytokine composed of p28 and EBI3 subunits, has been reported to exert potent antitumor activity in several cancer models. However, the precise role of IL-27 in the pathogenesis of CRC remains unclear. Here, we show that during the azoxymethane (AOM)/dextran sodium sulfate (DSS)-induced CRC development, IL-27p28 levels are dramatically increased in peripheral blood and tumor tissues, and the cytokine is mainly produced by tumor-infiltrating myeloid cells. IL-27p28 deficient mice display tumor resistances in both inflammation-associated CRC model and syngeneic MC38 colon cancer model. Administration with IL-27p28 neutralizing antibody also reduces the tumor formation in AOM/DSS-treated mice. Mechanically, CD8+ T cells in IL-27p28-/- mice exhibit enhanced tumor infiltration and cytotoxicity, which can be largely attributed to activation of the Akt/mTOR signaling pathway. Furthermore, selective depletion of CD8+ T cells in IL-27p28-/- mice markedly accelerate tumor growth and almost abrogate the protective effects of IL-27p28 deficiency. Most interestingly, the expression of IL-27p28 is also upregulated in tumor tissues of CRC patients and those with high expression of IL-27p28 tend to have a poorer overall survival. Our results suggest that loss of IL-27p28 suppresses colorectal tumorigenesis by augmenting CD8+ T cell-mediated anti-tumor immunity. Targeting IL-27p28 could be developed as a novel strategy for the treatment of colorectal cancers.

Tislelizumab Plus Platinum and Etoposide Versus Placebo Plus Platinum and Etoposide as First-Line Treatment for Extensive-Stage SCLC (RATIONALE-312): A Multicenter, Double-Blind, Placebo-Controlled, Randomized, Phase 3 Clinical Trial.

INTRODUCTION: Extensive-stage SCLC (ES-SCLC) prognosis remains poor. The phase 3 RATIONALE-312 study aimed to evaluate the efficacy and safety of tislelizumab plus chemotherapy as first-line treatment for ES-SCLC. METHODS: RATIONALE-312 is a randomized, double-blind, placebo-controlled trial, conducted in the People's Republic of China. Eligible patients with previously untreated ES-SCLC were randomized 1:1 to receive four cycles of tislelizumab 200 mg or placebo, with etoposide plus carboplatin or cisplatin intravenously every 3 weeks, followed by tislelizumab 200 mg or placebo as maintenance. The primary end point was overall survival (OS). Secondary end points included progression-free survival and safety. RESULTS: Between July 22, 2019 and April 21, 2021, 457 patients were randomized to tislelizumab (n = 227) or placebo (n = 230), plus chemotherapy. Baseline demographics were generally balanced between arms. At the data cutoff (April 19, 2023), the median study follow-up was 14.2 months (interquartile range: 8.6-25.3). Tislelizumab plus chemotherapy exhibited a statistically significant OS benefit versus placebo plus chemotherapy (stratified hazard ratio = 0.75 [95% confidence interval (CI): 0.61-0.93]; one-sided p = 0.0040; median: 15.5 [95% CI: 13.5-17.1] versus 13.5 mo [95% CI: 12.1-14.9], respectively). Progression-free survival was significantly improved in the tislelizumab versus placebo arm (stratified hazard ratio = 0.64 [95% CI: 0.52-0.78]; p < 0.0001; median: 4.7 [95% CI: 4.3-5.5] versus 4.3 mo [95% CI: 4.2-4.4], respectively). Grade greater than or equal to 3 treatment-related adverse events were reported in 86% of patients in each treatment arm and were mostly hematologic. CONCLUSIONS: Tislelizumab plus chemotherapy exhibited statistically significant clinical benefit and manageable safety compared with placebo plus chemotherapy as first-line treatment in patients with advanced ES-SCLC.

Effectiveness and safety of anlotinib with or without S-1 in the treatment of patients with advanced hepatocellular carcinoma in a Chinese population: a prospective, phase 2 study.

BACKGROUND: The aim of the study was to observe the safety and efficacy of anlotinib (ANL) alone or combined with S-1 in the first-line treatment of advanced hepatocellular carcinoma (HCC). PATIENTS AND METHODS: Fifty-four patients with untreated advanced HCC who could not be resected were randomly divided into the ANL group (n = 27) and ANL+S-1 group (n = 27). The ANL group was given 10 mg ANL orally once a day for 14 consecutive days, stopped for 1 week, and repeated every 21 days. The ANL+S-1 group was given 10 mg ANL once a day orally and 40 mg S-1 twice a day orally for 14 consecutive days, stopped for 1 week, repeated every 21 days. All patients were treated until the disease progressed or toxicity became unacceptable. For patients who could not tolerate adverse reactions, the ANL dose should be reduced to 8 mg per day. CT or MRI was reviewed every 6 weeks to evaluate the efficacy. RESULTS: A total of 44 patients were included in the results analysis, including 22 patients in the ANL group and 22 patients in the ANL+S-1 group. In the ANL group, the objective response rate (ORR) was 4.5% (1/22), the disease control rate (DCR) was 77.3% (17/22), the median progression-free survival (PFS) was 4.2 months (95% CI: 3.6-6.0) and the median overall survival (mOS) was 7.0 months (95% CI: 6.3-9.0). In the ANL+S-1 group, the ORR was 18.2% (4/22), the DCR was 59.1% (13/22), the median PFS was 4.0 months (95% CI: 3.6-5.4) and the mOS was 6.0 months (95% CI: 5.5-7.4). There was no significant difference in ORR (p = 0.345) or DCR (p = 0.195) between the two groups. Adverse reactions were mainly hypertension, anorexia, fatigue, liver transaminase heightened and hand and foot skin reaction. CONCLUSIONS: ANL monotherapy was effective in the treatment of advanced HCC, and adverse reactions have been able to tolerated.

Efficacy and safety of KN046, a novel bispecific antibody against PD-L1 and CTLA-4, in patients with non-small cell lung cancer who failed platinum-based chemotherapy: a phase II study.

BACKGROUND: This study aimed to evaluate the efficacy and safety of KN046, a novel recombinant humanised antibody targeting PD-L1 and CTLA-4 in advanced non-small cell lung cancer (NSCLC) patients after failure or intolerance to platinum-based chemotherapy. METHODS: In this multi-centre, open-label phase II clinical trial, patients were enroled after failure or intolerance to platinum-based chemotherapy. KN046 at 3 mg/kg or 5 mg/kg was administered intravenously every 2weeks. The primary end-point was objective response rate (ORR) evaluated by a blinded independent review committee (BIRC). RESULTS: A total of 30 and 34 patients were included in the 3 mg/kg (cohort A) and 5 mg/kg (cohort B) cohorts. On 31st August 2021, the median follow-up duration was 24.08 months (interquartile [IQR], 22.28, 24.84) and 19.35months (IQR, 17.25, 20.90) in the 3 mg/kg and 5 mg/kg cohorts, respectively. BIRC-assessed ORRs were 13.3% and 14.7% in the 3 mg/kg and 5 mg/kg cohorts, respectively. Median progression-free survival was 3.68 (95% confidence interval [CI] 3.22-7.29) and 3.68 (95%CI 1.81-7.39) months, while overall survival was 19.70 (95.5%CI 15.44-not estimated [NE]) and 13.04 (95.5%CI 9.86-NE) months, respectively. The most common treatment-related adverse events (TRAEs) were anaemia (28.1%), hyperglycaemia (26.7%), and infusion-related reactions (26.7%). The incidence rates of grade ≥ 3 TRAEs and TRAEs leading to treatment discontinuation were 42.2% and 14.1%, respectively. CONCLUSIONS: Both 3 mg/kg and 5 mg/kg KN046 showed promising efficacy and favourable safety profile for advanced NSCLC after failure or intolerance to previous platinum-based chemotherapy. TRIAL REGISTRATION NUMBER: NCT03838848.

Case report: Novel junctional sarcoplasmic reticulum protein 1 intergenic region-anaplastic lymphoma kinase fusion in a patient with lung adenocarcinoma responds to alectinib.

Novel anaplastic lymphoma kinase (ALK) fusions are still being discovered in non-small cell lung cancer (NSCLC). Most patients with ALK+ NSCLC respond favorably to ALK tyrosine kinase inhibitors. In this case report, we identified a novel nonreciprocal ALK fusion, namely, junctional sarcoplasmic reticulum protein 1 (JSRP1) intergenic region-ALK fusion (Jintergenic: A20) via next-generation sequencing in a female patient initially diagnosed with stage IV B lung adenocarcinoma. Further examination of biopsy specimen and analysis of clinical samples by a multidisciplinary team confirmed the diagnosis of ALK+ NSCLC. At the 2- and 4-months follow-up after receiving alectinib, the patient responded rapidly, implying that alectinib had a remarkable therapeutic effect. We identified a novel JSRP1 intergenic region-ALK fusion as a carcinogenic mutation that responds to alectinib, thereby expanding the spectrum of ALK fusion partners in ALK + NSCLC. This study may help clinicians detect oncogenic mutations and provide timely treatment to patients with ALK+ NSCLC.

A prospective, open-label, multicenter phase IV clinical trial on the safety and efficacy of lobaplatin-based chemotherapy in advanced breast cancer.

Background: Since lobaplatin (LBP) has been approved to treat metastatic breast cancer in China, this study aimed to evaluate the safety and efficacy of LBP-based chemotherapy in clinical practice. Methods: This trial was a prospective, open-label, multicenter phase IV clinical trial that enrolled patients with unresectable locally advanced or recurrent/metastatic breast cancer from 34 sites between July 2013 and March 2017. Patients were treated with LBP monotherapy or in combination for four to six cycles. The primary endpoint was safety. Secondary endpoints included progression-free survival (PFS), objective response rate (ORR), and disease control rate (DCR). Results: A total of 1179 patients were analyzed; 59 (5.0%) were treated with LBP alone, 134 (11.4%) with LBP plus paclitaxel, 263 (22.3%) with LBP plus docetaxel, 237 (20.1%) with LBP plus gemcitabine, 403 (34.2%) with LBP plus vinorelbine, and 83 (7.0%) with other LBP-based regimens. The overall incidence of adverse events (AEs) was 95.2%, and 57.9% of patients had grade >3 AEs. The most common grade >3 AEs were neutropenia (43.9%), leukopenia (39.4%), anemia (17.8%), and thrombopenia (17.7%). LBP monotherapy showed the lowest incidence of grade >3 AEs (39.0%), followed by LBP plus docetaxel (52.9%), LBP plus paclitaxel (59.0%), LBP plus vinorelbine (62.5%), and LBP plus gemcitabine (62.9%). The ORR and DCR were 36.8 and 77.0%, respectively. The median PFS was 5.5 months (95% confidence interval: 5.2-5.9). Conclusion: LBP-based chemotherapy shows favorable efficacy in patients with advanced breast cancer, with manageable safety profile. Trial registration: This trial was registered with ChiCTR.org.cn, ChiCTR-ONC-13003471.

Recombinant Human IL-11 Promotes Lung Adenocarcinoma A549 Cell Growth and EMT through Activating STAT3/HIF-1α/EMT Signaling Pathway.

BACKGROUND: Interleukin-11 (IL-11) could promote invasion and metastasis of cancer cells, however, its mechanism is unclear. OBJECTIVE: This study aimed to investigate the effects of recombinant human IL-11 (rhIL-11) on lung cancer cell metastasis and growth. METHODS: Human lung cancer cell, A549, was cultured and subcutaneously injected into mice to establish Xenograft tumor models. Tumor models were divided into control, rhIL-11 transplantation (250 µg/kg/day), and rhIL-11 transplantation (500 µg/kg/day) group. Tumor volumes were recorded and measured 6 times. Hypoxia- Inducible Factor 1α (HIF1α), snail, slug, Signal Transducers/Activators of Transcription-3 (STAT3), E-cadherin, twist, and vimentin levels were evaluated using western blot and Real-Time PCR (RT-PCR). RESULTS: Sizes of subcutaneous tumors increased following measurement time. rhIL-11 treatment significantly enhanced HIF1α and STAT3 expression in rhIL-11 treatment groups compared to the control group (p<0.05). However, no remarkable differences were discovered between rhIL-11 (250 µg/kg/day) and rhIL-11 (500 µg/kg/day) group (p>0.05). rhIL-11 treatments significantly increased twist, and slug expressions compared to control group (p<0.05), especially for rhIL-11 (500 µg/kg/day) treatment, which triggered significantly higher effects on twist and slug expressions compared to those in the control group (p<0.05). Vimentin and snail mRNA levels were significantly up-regulated and E-cadherin level was significantly down-regulated in rhIL-11 treatment groups compared to the control group (p<0.05). Meanwhile, rhIL-11 at a dosage of 500 µg/kg/day triggered remarkably higher effects on vimentin, snail, and E-cadherin expressions compared to those in rhIL-11 (250 µg/kg/day) group (p<0.05). CONCLUSION: rhIL-11 transplantation promoted growth and Epithelial-Mesenchymal Transition (EMT) of A549 cells, which might be associated with STAT3/HIF-1α/EMT signaling pathway activation.

Bevacizumab biosimilar LY01008 compared with bevacizumab (Avastin) as first-line treatment for Chinese patients with unresectable, metastatic, or recurrent non-squamous non-small-cell lung cancer: A multicenter, randomized, double-blinded, phase III trial.

BACKGROUND: Previous studies have demonstrated the preclinical pharmacological and toxicological consistency, and clinical pharmacokinetic equivalence of bevacizumab biosimilar LY01008 with reference bevacizumab (Avastin). This randomized controlled trial aimed to compare the efficacy and safety of LY01008 with Avastin in first-line treatment of Chinese patients with advanced or recurrent non-squamous non-small cell lung cancer (NSCLC). METHODS: Stage IIIB-IV NSCLC patients with evaluable lesions, good physical status, and adequate organ functions from 67 centers across China were randomized in a ratio of 1:1 to receive LY01008 or Avastin 15 mg/kg intravenously in combination with paclitaxel/carboplatin (combined treatment) for 4-6 cycles, followed by maintenance monotherapy with LY01008 until disease progression, intolerable toxicity, or death. The primary endpoint was objective response rate (ORR) in accordance with Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 confirmed by independent radiological review committees (IRRC). Secondary endpoints included disease control rate (DCR), duration of response (DoR), progression-free survival (PFS), overall survival (OS), and safety. This study was registered in ClinicalTrials.gov (NCT03533127). RESULTS: Between December 15th , 2017, and May 15th , 2019, a total of 649 patients were randomized to the LY01008 (n = 324) or Avastin (n = 325) group. As of September 25th , 2019 for primary endpoint analysis, 589 patients received ORR evaluation, with a median number of combined treatment cycles of 5 (range 1-6) and median duration of treatment of 3.0 (range 0.0-5.1) months. ORR of response-evaluable patients in the LY01008 and Avastin groups were 48.5% and 53.0%, respectively. The stratified ORR ratio was 0.91 (90% CI 0.80-1.04, within the prespecified equivalence margin of 0.75-1.33). Up to May 15th , 2020, with a median follow-up of 13.6 (range 0.8-28.4) months, no notable differences in DCR, median DoR, median PFS, median OS, and 1-year OS rate were observed between the LY01008 and Avastin groups. There were no clinically meaningful differences in safety and immunogenicity across treatment groups. CONCLUSIONS: LY01008 demonstrated similarity to Avastin in terms of efficacy and safety in Chinese patients with advanced or recurrent non-squamous NSCLC. LY01008 combined with paclitaxel/carboplatin is expected to become a new treatment option for unresectable, metastatic, or recurrent non-squamous NSCLC patients in the first-line setting.

Association of HIF-1α and NDRG2 Expression with EMT in Gastric Cancer Tissues.

OBJECTIVE: This study aims to investigate the differences in the expression of hypoxia-inducible factor-1α (HIF-1α), N-myc downstream-regulated gene 2 (NDRG2) and epithelial mesenchymal transition (EMT)-related proteins in normal gastric tissues, gastric cancer tissues and lymph node metastasis. METHODS: Immunohistochemistry was used to detect the expression of HIF-1α, NDRG2, E-cadherin, Snail and Twist in normal gastric tissues, gastric cancer tissues and lymph node metastasis. RESULTS: In normal gastric tissues, HIF-1α was not expressed, NDRG2 was highly expressed. There was a significant between the expression of NDRG2 and Snail, as well as of NDRG2 and Twist. In gastric cancer tissues, there was no statistically difference between the expression of HIF-1α and E-cadherin, NDRG2 and E-cadherin. However, there was a significant difference in expression between the expression of HIF-1α and Snail, HIF-1α and Twist, NDRG2 and Snail, and NDRG2 and Twist. In lymph node metastasis tissues, we show that HIF-1α was highly expressed, while NDRG2 was not, and the difference between the expression of HIF-1α and E-cadherin, HIF-1α and Snail, HIF-1α and Twist was not significant. CONCLUSION: HIF-1α may promote EMT, possibly by inhibiting the expression of NDRG2.

LncRNA DGCR5 regulates the non-small cell lung cancer cell growth, migration, and invasion through regulating miR-211-5p/EPHB6 axis.

Non-small cell lung cancer (NSCLC) accounts for about 80% of lung cancers worldwide. In recent years, importance of noncoding RNAs including long noncoding RNA and microRNA in regulating tumor progression has been appreciated. Abnormally expression of DiGeorge syndrome critical region gene 5 (DGCR5) was found in multiple human cancers but its function in NSCLC is largely unknown. Reverse transcription quantitative polymerase chain reaction (RT-qPCR) was conducted to explore DGCR5 expression level in NSCLC. Bioinformatic analyses were conducted to explore the targets of DGCR5. Cell counting kit-8 assay, wound-healing assay, and transwell invasion assay were performed to analyze functions of DGCR5. RT-qPCR revealed that DGCR5 expression in NSCLC cells was significantly lower than in normal cell. DGCR5 overexpression suppresses NSCLC cell growth, migration, and invasion. Online algorithms found EPH receptor B6 (EPHB6) and DGCR5 contains same miR-211-5p binding region. The predicted connections were further validated by luciferase activity reporter assay. Recue experiments showed DGCR5 regulates NSCLC cell behaviors via targeting miR-211-5p/EPHB6. These findings collectively identified DGCR5/miR-211-5p/EPHB6 triple axis in NSCLC, which may novel understanding regarding the tumorigenesis of NSCLC.

MicroRNA-211 promotes non-small-cell lung cancer proliferation and invasion by targeting MxA.

Recent studies have shown that microRNAs play a pivotal role in the pathogenesis of cancer. In our current study, the expression levels of microRNA-211 (miR-211) were measured in human non-small-cell lung cancer (NSCLC) tissues and cell lines. We found that miR-211 expression levels were increased in NSCLC tissues and cell lines and that the overexpression of miR-211 promotes cell proliferation and invasion. Using bioinformatics, we demonstrated that miR-211 binds to the 3'-untranslated region of MxA and overexpression of miR-211 suppresses the expression of MxA at both the transcriptional and translational levels in NSCLC cell lines. Furthermore, knockdown of MxA increased the proliferation and invasion of NSCLC cell lines in vitro. High levels of miR-211 expression were associated with a shorter survival time in patients with NSCLC. Taken together, these results suggest that miR-211 promotes tumor proliferation and invasion by regulating MxA expression in NSCLC. This study provides insights into molecular mechanisms of miR-211-mediated tumorigenesis and oncogenesis.

Sox12 Is a Cancer Stem-Like Cell Marker in Hepatocellular Carcinoma.

Recent studies on molecular carcinogenesis suggest that the chemo-resistance of some cancers is largely due to presence of cancer stem cells (CSCs), which affect the chemotherapy outcome for hepatocellular carcinoma (HCC). However, currently no consensus on a CSC phenotype in HCC has been obtained. Here, we examined Sox12 as a novel CSC marker in HCC. Sox12+ versus Sox12- cells were purified from HCC cell lines. The Sox12+ cells were compared with Sox12- HCC cells for tumor sphere formation, chemo-resistance, tumor formation after serial adoptive transplantations in nude mice, and the frequency of developing distal metastasis. We found that compared to Sox12- HCC cells, Sox12+ HCC cells generated significantly more tumor spheres in culture, were more chemo-resistant to cisplatin, were detected in circulation more frequently, and formed distal tumor more frequently. Moreover, Sox12 appeared to functionally contribute to the stemness of HCC cells. Thus, we conclude that Sox12 may be a novel marker for enriching CSCs in HCC.

Overexpression of STAT3/pSTAT3 was associated with poor prognosis in gastric cancer: a meta-analysis.

Signal transducer and activator of transcription 3 (STAT3) and phospho-STAT3 (pSTAT3) play important roles in the development of gastric cancer. STAT3 is often associated with cell survival, proliferation, and transformation. The prognostic value of STAT3/pSTAT3 in patients with gastric cancer remains controversial in numerous published studies. The aim of this study was to summarize recent findings relevant to the prognostic role of STAT3 and pSTAT3 in patients with gastric cancer. A meta-analysis was performed by searching Web of Knowledge, EMBASE, and PubMed to identify studies on the prognostic impact of STAT3/pSTAT3 in gastric cancers in August 2014. In all, 10 studies were included in the analysis. Data were collected for comparing survival rates in patients with high STAT3 levels compared to those with low levels. Pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated. Sensitivity analysis was conducted, and publication bias was evaluated. Eventually, 1667 cases of gastric cancer were subjected to the final analysis. Among patients with gastric cancer, poor survival was predicted by higher expressions of STAT3 (HR=2.30; 95% CI=1.13-4.68; P=0.02) and pSTAT3 (HR=1.75; 95% CI=1.17-2.61; P=0.006). Moreover, overexpression of STAT3 was associated with poor tumor stage. Additionally, our analysis did not show any statistically significant effect of publication bias regarding STAT3 or pSTAT3. The results of this meta-analysis demonstrated that overexpression of STAT3 and pSTAT3 was associated with poor prognosis in gastric cancer.

[Weekly irinotecan plus capecitabine as a second-line chemotherapy for advanced gastric cancer: an analysis of 21 cases].

OBJECTIVE: To evaluate the efficacy and adverse effects of weekly irinotecan combined with capecitabine as a second-line chemotherapy for treatment of advanced gastric cancer. METHODS: Twenty-one patients with advanced gastric cancer who had failed first-line therapy received irinotecan on days 1 and 8 plus capecitabine on days 1-14 for a 21-day cycle. Each patient was treated for at least two cycles and evaluated 4 weeks later for the responses. RESULTS: Of the 21 patients, none showed complete remission (CR), 5 (23.8%) showed partial remission (PR), 6 (28.6%) showed stable disease (SD) and 10 (47.6%) showed progressive disease (PD). The overall response rate was 23.8%, and 11 patients (52.4%) benefited (CR+PR+SD) from the clinical therapy, with a mean time to tumor progression of 3.61±0.97 months. The main adverse effects of this regimen included myelosuppression, nausea, vomiting and diarrhea. CONCLUSION: The regimen of weekly irinotecan plus capecitabine has a definite effect for treatment of advanced gastric cancer with tolerable toxicity.

[The effects of pravastatin on platelet-derived nitric oxide system in rabbits].

OBJECTIVE: To observe the effects of pravastatin on platelet-derived nitric oxide system in hypercholesterolemia (HC) and atherosclerosis (AS) in rabbits, and the relationship between these changes and atherosclerosis courses. METHODS: Thirty male New Zealand white rabbits were randomly divided into three groups, 12 in group A, 12 in group B, and 6 in group C. All of them were fed daily with cholesterol-rich food during the first 12 weeks. In addition, in group A, pravastatin (10 mg) was orally administered daily. At the end of the 12th week, 6 in group A and B were killed randomly and their aortas were removed and the pathologic changes were observed. In the following 12 weeks, food enriched with cholesterol was substituted with normal food in all three groups. Pravastatin treatment was continued or started in the remaining members of group A and group B, but not in group C. At the end 24th week, all rabbits were killed and their aortas were examined for the fatty-streaks or atherosclerotic plaques. The expressions of endothelial NOS (eNOS) mRNA and inducible NOS (iNOS ) mRNA, NOS activity, NO production and the level of the serum lipids were measured at 0, 6th, 12th, 18th and 24th week. RESULTS: The expression levels of platelet-derived NOS mRNA, eNOS mRNA ratio in group A had no difference at above time points, while in group B were reduced significantly at 6th week and 12th week compared with at 0 week (P <0.01), and increased at 18th week and 24th week compared with 12th week (P <0.05). The expression levels of eNOS mRNA in group C were reduced at 6th, 12th and 18th, 24th week compared with 0 week (P <0.05 and P <0.01, respectively), and were reduced in groups B and C compared with group A at 6th ,12th week (P < 0.05) and increased in group A and B compared with group C at 18th, 24th week (P <0.01). The expression levels of iNOS/mRNA among the three groups had no difference. Pathologic finding of the arteries: AS was not found in group A from the 12th to 24th week. While in group B, there were a lot of fatty-streaks on the entire intima of all large arteries at the 12th week. There were also fatty-streaks in the ascending aorta, but were improved at the 24th week. In group C, there were marked plaques in the entire aorta at the 24th week. CONCLUSIONS: The expressions of platelet-derived eNOS mRNA, NOS activity, NO production are decreased in HC or AS rabbits. Pravastatin can up-regulate expressions of platelet-derived eNOS mRNA, NOS activity, leading to preventing or improving the pathological courses of AS.