肺癌miR-146a表达及其对细胞增殖、侵袭及迁移的影响

目的探讨微小RNA-146a(miR-146a)在肺癌组织和细胞中的表达和甲基化状态,及其对A549细胞增殖、侵袭、迁移的影响及可能机制。方法收集2018年1月至2019年4月在我院行根治性手术的非小细胞肺癌组织和对应癌旁组织,实时荧光定量PCR(QPCR)和甲基化特异性PCR(MSP)检测miR-146a的表达水平和甲基化状态,并分析甲基化状态与肺癌临床病理特征的关系。采用5-氮杂-2’-脱氧胞苷(5-AZA-2’-dC)处理A549细胞(处理组),MTT、Transwell实验和划痕实验检测处理组细胞增殖、侵袭和迁移活性。采用Western blotting检测Notch1和发状分裂相关增强子1(Hes-1)蛋白表达。结果肺癌组织和A549细胞中miR-146a表达量分别为0.63±0.28、0.85±0.11,均低于癌旁正常组织和BEAS-2B细胞(P<0.05)。MSP检测显示肺癌组织miR-146a甲基化率为62.5%(50/80),高于癌旁组织(P<0.05);miR-146a甲基化状态与肿瘤直径、TNM分期、淋巴结转移有关(P<0.05)。处理组细胞miR-146a表达水平为2.15±0.48,高于空白对照组(P<0.05);处理组细胞增殖、侵袭和迁移活性均低于空白对照组(P<0.05)。处理组Notch1蛋白和Hes-1蛋白表达水平分别为0.24±0.05和0.22±0.06,均低于空白对照组(P<0.05)。结论启动子异常甲基化导致在肺癌组织和细胞中miR-146a表达量降低,可能通过减弱对Notch1/Hes-1信号通路的抑制作用,促进肺癌细胞增殖、侵袭和转移,miR-146a有望成为肺癌新的生物治疗靶点。     

Pathogenesis of chronic lymphocytic leukemia and the development of novel therapeutic strategies

Chronic lymphocytic leukemia (CLL) is the most common adult leukemia in Western countries and is characterized by the clonal expansion of mature CD5⁺ B cells. There have been substantial advances in the field of CLL research in the last decade, including the identification of recurrent mutations, and clarification of clonal architectures, signaling molecules, and the multistep leukemogenic process, providing a comprehensive understanding of CLL pathogenesis. Furthermore, the development of therapeutic approaches, especially that of molecular target therapies against CLL, has markedly improved the standard of care for CLL. This review focuses on the recent insights made in CLL leukemogenesis and the development of novel therapeutic strategies.     

Suppression of KIF3A inhibits triple negative breast cancer growth and metastasis by repressing Rb‐E2F signaling and epithelial‐mesenchymal transition

Triple negative breast cancer (TNBC) displays higher heterogeneity, stronger invasiveness, higher risk of metastasis and poorer prognosis compared with major breast cancer subtypes. KIF3A, a member of the kinesin family of motor proteins, serves as a microtubule‐directed motor subunit and has been found to regulate early development, ciliogenesis and tumorigenesis. To explore the expression, regulation and mechanism of KIF3A in TNBC, 3 TNBC cell lines, 98 cases of primary TNBC and paired adjacent tissues were examined. Immunohistochemistry, real‐time PCR, western blot, flow cytometry, short hairpin RNA (shRNA) interference, 3‐(4,5‐dimethylthiazol‐2‐yl)‐2,5‐diphenyltetrazolium bromide (MTT), colony formation techniques, transwell assays, scratch tests, and xenograft mice models were used. We found that KIF3A was overexpressed in TNBC and such high KIF3A expression was also associated with tumor recurrence and lymph node metastasis. Silencing of KIF3A suppressed TNBC cell proliferation by repressing the Rb‐E2F signaling pathway and inhibited migration and invasion by repressing epithelial‐mesenchymal transition. The tumor size was smaller and the number of lung metastatic nodules was lower in KIF3A depletion MDA‐MB‐231 cell xenograft mice than in the negative control group. In addition, KIF3A overexpression correlated with chemoresistance. These results suggested that high expression of KIF3A in TNBC was associated with the tumor progression and metastasis.     

Nuclear magnetic resonance‐based tissue metabolomic analysis clarifies molecular mechanisms of gastric carcinogenesis

Gastric cancer (GC) is one of the deadliest cancers worldwide, and the progression of gastric carcinogenesis (GCG) covers multiple complicated pathological stages. Molecular mechanisms of GCG are still unclear. Here, we undertook NMR‐based metabolomic analysis of aqueous metabolites extracted from gastric tissues in an established rat model of GCG. We showed that the metabolic profiles were clearly distinguished among 5 histologically classified groups: control, gastritis, low‐grade gastric dysplasia, high‐grade gastric dysplasia (HGD), and GC. Furthermore, we carried out metabolic pathway analysis based on identified significant metabolites and revealed significantly disturbed metabolic pathways closely associated with the 4 pathological stages, including oxidation stress, choline phosphorylation, amino acid metabolism, Krebs cycle, and glycolysis. Three metabolic pathways were continually disturbed during the progression of GCG, including taurine and hypotaurine metabolism, glutamine and glutamate metabolism, alanine, aspartate, and glutamate metabolism. Both the Krebs cycle and glycine, serine, and threonine metabolism were profoundly impaired in both the HGD and GC stages, potentially due to abnormal energy supply for tumor cell proliferation and growth. Furthermore, valine, leucine, and isoleucine biosynthesis and glycolysis were significantly disturbed in the GC stage for higher energy requirement of the rapid growth of tumor cells. Additionally, we identified potential gastric tissue biomarkers for metabolically discriminating the 4 pathological stages, which also showed good discriminant capabilities for their serum counterparts. This work sheds light on the molecular mechanisms of GCG and is of benefit to the exploration of potential biomarkers for clinically diagnosing and monitoring the progression of GCG.     

Wnt/β-Catenin Signaling Pathway as Chemotherapeutic Target in Breast Cancer: An Update on Pros and Cons

The Wnt/β-catenin pathway, in addition to playing a crucial role in the development of the mammary gland during embryogenesis and during pregnancy, is one of the most commonly altered pathways in breast cancer. Accumulating findings from in vitro and in vivo and clinical studies have been suggestive of this pathway as a potential chemotherapy target. However, approved chemotherapeutic agents targeting this pathway are still missing for the treatment of patients with cancer. None of the clinical trials on the Wnt/β-catenin pathway inhibitors have translated beyond phase I/II studies. Hence, detailed analysis of the alterations in this pathway and the therapeutic agents modulating Wnt/β-catenin signaling components in breast cancer is warranted. The present review explored the latest developments in the association of deregulation in the Wnt/β-catenin signal cascade with the pathogenesis of breast cancer, the progress in identifying the potential chemotherapeutic drugs inhibiting this pathway, and the status of these compounds in clinical trials of breast cancer.     

Inhibiting Pathways Predicted From a Steroid Hormone Gene Signature Yields Synergistic Antitumor Effects in NSCLC

IntroductionMounting evidence supports a role for estrogen signaling in NSCLC progression. We previously reported a seven-gene signature that predicts prognosis in estrogen receptor β positive (ERβ+) NSCLC. The signature defines a network comprised of ER and human EGFR-2/3 (HER2/HER3) signaling.MethodsWe tested the efficacy of combining the pan-HER inhibitor, dacomitinib, with the estrogen antagonist, fulvestrant, in ERβ+ NSCLC models with differing genotypes. We assessed the potency of this combination on xenograft growth and survival of host mice, and the ability to reverse the gene signature associated with poor outcome.ResultsSynergy was observed between dacomitinib and fulvestrant in three human ERβ+ NSCLC models: 201T (wild-type EGFR), A549 (KRAS mutant), and HCC827 (EGFR 19 deletion) with combination indices of 0.1-0.6. The combination, but not single agents, completely reversed the gene signature associated with poor prognosis in a mechanism that is largely mediated by activator protein 1 downregulation. In vivo, the combination also induced tumor regression and reversed the gene signature. In HCC827 xenografts treated with the combination, survival of mice was prolonged after therapy discontinuation, tumors that recurred were less aggressive, and two mechanisms of HER inhibitor resistance involving c-Met activation and PTEN loss were blocked.ConclusionsThe combination of an ER blocker and a pan-HER inhibitor provides synergistic efficacy in different models of ERβ+ NSCLC. Our data support the use of this combination clinically, considering its ability to induce potent antitumor effects and produce a gene signature that predicts better clinical outcomes.     

七氟烷预处理对大鼠骨髓间充质干细胞在缺氧复氧环境下的作用和机制初探

目的:研究七氟烷预处理对大鼠骨髓间充质干细胞（MSCs）在缺氧复氧环境下的作用和机制初探。方法:分离培养SD大鼠骨髓间充质干细胞,通过流式细胞仪和诱导分化培养鉴定其免疫表型和分化潜能。细胞随机分为3组:组1空白对照组;组2缺氧复氧组（缺氧24 h,复氧24 h）;组3七氟烷预处理组（2%七氟烷预处理2 h后,缺氧24 h,复氧24 h）。处理后收集各组细胞,用流式细胞仪测定其凋亡率,线粒体膜电位变化及细胞周期。Western blot测定细胞外调节蛋白激酶（ERK）的蛋白表达。结果:与组2相比,组3 MSCs凋亡率明显下降,处于S期细胞增多,细胞增殖能力增强。Western blot结果显示:与组2相比,组3磷酸化ERK蛋白表达上升。结论:七氟烷预处理能提高缺氧复氧环境下骨髓间充质干细胞存活率,降低MSCs凋亡数量,并能增强MSCs的增殖能力,这一机制与七氟烷促进MSCs细胞p-ERK蛋白表达相关。     

Adaptive response of resistant cancer cells to chemotherapy

Despite advances in cancer therapeutics and the integration of personalized medicine, the development of chemoresistance in many patients remains a significant contributing factor to cancer mortality. Upon treatment with chemotherapeutics, the disruption of homeostasis in cancer cells triggers the adaptive response which has emerged as a key resistance mechanism. In this review, we summarize the mechanistic studies investigating the three major components of the adaptive response, autophagy, endoplasmic reticulum (ER) stress signaling, and senescence, in response to cancer chemotherapy. We will discuss the development of potential cancer therapeutic strategies in the context of these adaptive resistance mechanisms, with the goal of stimulating research that may facilitate the development of effective cancer therapy.