Humanβ-defensin-1 affects the mammalian target of rapamycin pathway and autophagy in colon cancer cells through long noncoding RNA TCONS_00014506

BACKGROUND Colorectal cancer has a low 5-year survival rate and high mortality.Humanβ-defensin-1(hBD-1)may play an integral function in the innate immune system,contributing to the recognition and destruction of cancer cells.Long non-coding RNAs(lncRNAs)are involved in the process of cell differentiation and growth.AIM To investigate the effect of hBD-1 on the mammalian target of rapamycin(mTOR)pathway and autophagy in human colon cancer SW620 cells.METHODS CCK8 assay was utilized for the detection of cell proliferation and determination of the optimal drug concentration.Colony formation assay was employed to assess the effect of hBD-1 on SW620 cell proliferation.Bioinformatics was used to screen potentially biologically significant lncRNAs related to the mTOR pathway.Additionally,p-mTOR(Ser2448),Beclin1,and LC3II/I expression levels in SW620 cells were assessed through Western blot analysis.RESULTS hBD-1 inhibited the proliferative ability of SW620 cells,as evidenced by the reduction in the colony formation capacity of SW620 cells upon exposure to hBD-1.hBD-1 decreased the expression of p-mTOR(Ser2448)protein and increased the expression of Beclin1 and LC3II/I protein.Furthermore,bioinformatics analysis identified seven lncRNAs(2 upregulated and 5 downregulated)related to the mTOR pathway.The lncRNA TCONS_00014506 was ultimately selected.Following the inhibition of the lncRNA TCONS_00014506,exposure to hBD-1 inhibited p-mTOR(Ser2448)and promoted Beclin1 and LC3II/I protein expression.CONCLUSION hBD-1 inhibits the mTOR pathway and promotes autophagy by upregulating the expression of the lncRNA TCONS_00014506 in SW620 cells.

Loss of monopolar spindle-binding protein 3B expression promotes colorectal cancer malignant behaviors by activation of target of rapamycin kinase/autophagy signaling

BACKGROUND Monopolar spindle-binding protein 3B(MOB3B)functions as a signal transducer and altered MOB3B expression is associated with the development of human cancers.AIM To investigate the role of MOB3B in colorectal cancer(CRC).METHODS This study collected 102 CRC tissue samples for immunohistochemical detection of MOB3B expression for association with CRC prognosis.After overexpression and knockdown of MOB3B expression were induced in CRC cell lines,changes in cell viability,migration,invasion,and gene expression were assayed.Tumor cell autophagy was detected using transmission electron microscopy,while nude mouse xenograft experiments were performed to confirm the in-vitro results.RESULTS MOB3B expression was reduced in CRC vs normal tissues and loss of MOB3B expression was associated with poor CRC prognosis.Overexpression of MOB3B protein in vitro attenuated the cell viability as well as the migration and invasion capacities of CRC cells,whereas knockdown of MOB3B expression had the opposite effects in CRC cells.At the molecular level,microtubule-associated protein light chain 3 II/I expression was elevated,whereas the expression of matrix metalloproteinase(MMP)2,MMP9,sequestosome 1,and phosphorylated mechanistic target of rapamycin kinase(mTOR)was downregulated in MOB3B-overexpressing RKO cells.In contrast,the opposite results were observed in tumor cells with MOB3B knockdown.The nude mouse data confirmed these in-vitro findings,i.e.,MOB3B expression suppressed CRC cell xenograft growth,whereas knockdown of MOB3B expression promoted the growth of CRC cell xenografts.CONCLUSION Loss of MOB3B expression promotes CRC development and malignant behaviors,suggesting a potential tumor suppressive role of MOB3B in CRC by inhibition of mTOR/autophagy signaling.

MicroRNA-451 from Human Umbilical Cord-Derived Mesenchymal Stem Cell Exosomes Inhibits Alveolar Macrophage Autophagy via Tuberous Sclerosis Complex 1/Mammalian Target of Rapamycin Pathway to Attenuate Burn-Induced Acute Lung Injury in Rats

Objective Our previous studies established that microRNA(miR)-451 from human umbilical cord mesenchymal stem cell-derived exosomes(hUC-MSC-Exos)alleviates acute lung injury(ALI).This study aims to elucidate the mechanisms by which miR-451 in hUC-MSC-Exos reduces ALI by modulating macrophage autophagy.Methods Exosomes were isolated from hUC-MSCs.Severe burn-induced ALI rat models were treated with hUC-MSC-Exos carrying the miR-451 inhibitor.Hematoxylin-eosin staining evaluated inflammatory injury.Enzyme-linked immunosorbnent assay measured lipopolysaccharide(LPS),tumor necrosis factor-α,and interleukin-1βlevels.qRT-PCR detected miR-451 and tuberous sclerosis complex 1(TSC1)expressions.The regulatory role of miR-451 on TSC1 was determined using a dual-luciferase reporter system.Western blotting determined TSC1 and proteins related to the mammalian target of rapamycin(mTOR)pathway and autophagy.Immunofluorescence analysis was conducted to examine exosomes phagocytosis in alveolar macrophages and autophagy level.Results hUC-MSC-Exos with miR-451 inhibitor reduced burn-induced ALI and promoted macrophage autophagy.MiR-451 could be transferred from hUC-MSCs to alveolar macrophages via exosomes and directly targeted TSC1.Inhibiting miR-451 in hUC-MSC-Exos elevated TSC1 expression and inactivated the mTOR pathway in alveolar macrophages.Silencing TSC1 activated mTOR signaling and inhibited autophagy,while TSC1 knockdown reversed the autophagy from the miR-451 inhibitor-induced.Conclusion miR-451 from hUC-MSC exosomes improves ALI by suppressing alveolar macrophage autophagy through modulation of the TSC1/mTOR pathway,providing a potential therapeutic strategy for ALI.

Rapamycin Potentiates the Antitumor Effect of 5-Fluorouracil in Colon Cancer by Enhancing Autophagy

Objective:To investigate whether the mTOR inhibitor rapamycin can enhance the growth suppression effect of 5-fluorouracil(5-FU)on colon cancer cells.Methods:CCK8 assays were used to examine cell survival.Flow cytometry and Western blotting were employed to detect cell proliferation,apoptosis,and related markers.Results:The combination of rapamycin and 5-FU exhibited greater cytotoxicity in cells compared to rapamycin or 5-FU alone.Notably,cells in the G0/G1 phase increased while cells in the S phase decreased in the combination group,consistent with changes in the levels of Cyclin D1 and PCNA.Rapamycin enhanced 5-FU-induced apoptosis in vitro by inducing caspase-dependent apoptosis,which is Bax/Bcl-2 related.Conclusion:The combination of rapamycin and 5-FU showed a significant synergistic anticancer effect by enhancing autophagy.This study supports that the combination of rapamycin with 5-FU is an effective and feasible approach for colorectal cancer treatment.

Rapamycin reverses ferroptosis by increasing autophagy in MPTP/MPP+-induced models of Parkinson's disease

Parkinson’s disease is a neurodegenerative disorder,and fe rroptosis plays a significant role in the pathological mechanism underlying Parkinson’s disease.Rapamycin,an autophagy inducer,has been shown to have neuroprotective effects in Parkinson’s disease.However,the link between rapamycin and ferroptosis in Parkinson’s disease is not entirely clear.In this study,rapamycin was administe red to a 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced Parkinson’s disease mouse model and a 1-methyl-4-phenylpyridinium-induced Parkinson’s disease PC12 cell model.The results showed that rapamycin improved the behavioral symptoms of Parkinson’s disease model mice,reduced the loss of dopamine neurons in the substantia nigra pars compacta,and reduced the expression of ferroptosis-related indicators(glutathione peroxidase 4,recombinant solute carrier family 7,member 11,glutathione,malondialdehyde,and reactive oxygen species).In the Parkinson’s disease cell model,rapamycin improved cell viability and reduced ferro ptosis.The neuroprotective effect of rapamycin was attenuated by a ferroptosis inducer(methyl(1S,3R)-2-(2-chloroacetyl)-1-(4-methoxycarbonylphenyl)-1,3,4,9-tetrahyyridoindole-3-carboxylate)and an autophagy inhibitor(3-methyladenine).Inhibiting ferro ptosis by activating autophagy may be an important mechanism by which rapamycin exerts its neuroprotective effects.Therefo re,the regulation of ferroptosis and autophagy may provide a therapeutic target for drug treatments in Parkinson’s disease.

A mixed blessing for liver transplantation patients—Rapamycin

Background:Liver transplantation(LT)is an effective treatment option for end-stage liver disease.Mammalian target of rapamycin(m TOR)inhibitors,such as rapamycin,are widely used post LT.Data sources:In this review,we focused on the anti-cancer activities and metabolic side effects of rapamycin after LT.The literature available on Pub Med for the period of January 1999-September 2022 was reviewed.The key words were rapamycin,sirolimus,liver transplantation,hepatocellular carcinoma,diabetes,and lipid metabolism disorder.Results:Rapamycin has shown excellent effects and is safer than other immunosuppressive regimens.It has exhibited excellent anti-cancer activity and has the potential in preventing hepatocellular carcinoma(HCC)recurrence post LT.Rapamycin is closely related to two long-term complications after LT,diabetes and lipid metabolism disorders.Conclusions:Rapamycin prevents HCC recurrence post LT in some patients,but it also induces metabolic disorders.Reasonable use of rapamycin benefits the liver recipients.

Fasting produces antidepressant-like effects via activating mammalian target of rapamycin complex 1 signaling pathway in ovariectomized mice

Recent studies have shown that a 9-hour fast in mice reduces the amount of time spent immobile in the forced swimming test.Howeve r,whether 9-hour fasting has therapeutic effects in female mice with depressive symptoms has not been established.Therefore,in this study,we simulated perimenopausal depression via an ovariectomy in mice,and subjected them to a single 9-hour fasting 7 days later.We found that the ovariectomy increased the time spent immobile in the forced swimming test,inhibited expression of the mammalian target of rapamycin complex 1 signaling pathway in the hippocampus and prefro ntal cortex,and decreased the density of dendritic spines in the hippocampus.The 9-hour acute fasting alleviated the above-mentioned phenomena.Furthermore,all of the antidepressant-like effects of 9-hour fasting were reve rsed by an inhibitor of the mammalian to rget of rapamycin complex 1.Electrophysiology data showed a remarkable increase in long-term potentiation in the hippocampal CA1 of the ovariectomized mice subjected to fasting compared with the findings in the ovariectomized mice not subjected to fasting.These findings show that the antidepressant-like effects of 9-hour fasting may be related to the activation of the mammalian target of the rapamycin complex 1 signaling pathway and synaptic plasticity in the mammalian hippocampus.Thus,fasting may be a potential treatment for depression.

Real-world five-year outcomes of FlexyRap®cobalt-chromium rapamycin-eluting stents with biodegradable polymer in patients with de-novo coronary artery disease

BACKGROUND The use of biodegradable polymer drug-eluting stents(BP-DES)has been proven to minimize restenosis and stent thrombosis.The current post-marketing monitoring was observed at the 5-year clinical outcomes of individuals who had been treated with FlexyRap®DES in the real world.AIM To assess the safety and effectiveness of FlexyRap®DES at the 5-year follow-up in real-world settings.METHODS Findings from a retrospective,multi-center,observational,post-market clinical follow-up study of patients treated with FlexyRap®DES for de novo coronary artery disease(CAD)were reported.During the 12-mo follow-up,the primary endpoint was target lesion failure,which was defined as the composite of cardiovascular death, target vessel myocardial infarction(TV-MI), and clinically driven target lesion revascularization.RESULTS The data of 500 patients received with FlexyRap®DES was obtained at the completion of the surveillance timeline of 5-year.After the implantation of FlexyRap®DES,the device success rate was 100%.Adverse events that led to major bleeding,permanent disability,or death were not experienced in the patients.The major adverse cardiac event rate at 12-mo,3-year,and 5-year follow-up was 1(0.2%),0(0%),and 1(0.2%)respectively with 0(0%)cardiovascular death,2(0.4%)TV-MI,and 0(0%)TLR compositely.Furthermore,late stent thrombosis was found in 2(0.4%)patients at the follow-up of 12-mo,very late stent thrombosis was observed in 2 patients(0.4%)at 3-year follow-up.CONCLUSION FlexyRap®DES was proved to be safe and efficacious in real-world patients with de novo CAD,indicating a lowered rate of cardiac events and stent thrombosis at 5-year follow-up.

Study on the molecular mechanism of rapamycin-induced autophagy in acute T lymphoblastic leukemia cells

Objective:To study the effect of different concentrations of rapamycin on the proliferation of acute leukemia CD4^(+)T-Jurkat cells,and to explore its mechanism from the aspect of autophagy.Methods:The effect of different concentrations of rapamycin on cell proliferation was detected by MTT assay;Apoptosis rate and cell cycle arrest were detected by flow cytometry;The changes of autophagic lysosomes were observed by acridine orange staining;Transcriptome sequencing data were used to analyze the differential expression of autophagy-related genes;The transcription and protein expression levels of autophagy-related genes were detected by RT-qPCR and Western Blot;The chromatin accessibility of the promoter region of autophagy gene was analyzed by FAIRE-qPCR.Results:Compared with the control group,rapamycin inhibited the proliferation of Jurkat cells in a concentration-and time-dependent manner.The cell cycle was arrested in G0/G1 phase,but it could not effectively induce apoptosis.Observed by acridine orange staining,the number of autophagic lysosomes increased after administration.RNA-seq data showed that rapamycin could significantly affect the transcription level of autophagy-related genes.After Jurkat cells were treated with different concentrations of rapamycin for 48 h,10 nM and 20 nM rapamycin could up-regulate the expression of ULK1,ATG13,ATG16L2,PI3K3R1,Raptor genes and down-regulate the expression of MAPK1 gene.At 50 nM,the expression levels of each gene were down-regulated.The chromatin accessibility of the autophagy gene promoter region also changed,which was basically consistent with the trend of gene expression.Conclusion:Rapamycin can inhibit the proliferation of Jurkat cells,block cell cycle and induce autophagy.Low concentrations of rapamycin promoted the expression of autophagy-related genes,while high concentrations inhibited their expression.

Osteopontin promotes gastric cancer progression via phosphatidylinositol-3-kinase/protein kinase B/mammalian target of rapamycin signaling pathway

BACKGROUND Gastric cancer(GC)is one of the most common malignant tumors.Osteopontin(OPN)is thought to be closely related to the occurrence,metastasis and prognosis of many types of tumors.AIM To investigate the effects of OPN on the proliferation,invasion and migration of GC cells and its possible mechanism.METHODS The mRNA and protein expression of OPN in the GC cells were analyzed by realtime quantitative-reverse transcription polymerase chain reaction and western blotting,and observe the effect of varying degree expression OPN on the proliferation and other behaviors of GC.Next,the effects of OPN knockdown on GC cells migration and invasion were examined.The short hairpin RNA(shRNA)and negative control shRNA targeting OPN-shRNA were transfected into the cells according to the manufacturer’s instructions.Non transfected cells were classified as control in the identical transfecting process.24 h after RNA transfection cell proliferation activity was detected by 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-diphenytetrazoliumromide assay,and cell invasiveness and migration were detected by Trans well assay.Meanwhile,the expression of protein kinase B(AKT),matrix metalloproteinase 2(MMP-2)and vascular endothelial growth factor(VEGF)in the human GC cell lines was detected by reverse transcription polymerase chain reaction and western blotting.RESULTS The results of this study revealed that OPN mRNA and protein expression levels were highly expressed in SGC-7901 cells.OPN knockdown by specific shRNA noticeably reduced the capabilities of proliferation,invasion and migration of SGC-7901 cells.Moreover,in the experiments of investigating the underlying mechanism,results showed that OPN knockdown could down-regulated the expression of MMP-2 and VEGF,it also decreased the phosphorylation of AKT.Meanwhile,the protein expression levels of MMP-2,VEGF and phosphorylated AKT was noticeable lower than that in control group in the GC cells after they were added to phosphatidylinositol-3-kinase(PI3K)inhibitor(LY294002).CONCLUSION These results suggested that OPN though PI3K/AKT/mammalian target of rapamycin signal pathway to upregulate MMP-2 and VEGF expression,which contribute SGC-7901 cells to proliferation,invasion and migration.Thus,our results demonstrate that OPN may serve as a novel prognostic biomarkers as well as a potential therapeutic targets for GC.

RNAi沉默STAT3基因联合mTOR抑制剂rapamycin诱导BEL-7402肝癌细胞凋亡

目的:探讨PI3K/AKT/mTOR和JAK/STAT3 2条信号转导途径共同作用对肝癌细胞凋亡的影响,为肝癌基因治疗提供依据。方法:选取对数生长期BEL-7402细胞,随机分为对照组、mTOR抑制剂rapamycin(Rapa)组、阴性质粒组、阴性质粒+Rapa组、STAT3-siRNA质粒组和STAT3-siRNA质粒+Rapa组,应用LipofectamineTM2000转染试剂将含有目的基因的质粒转染BEL-7402细胞,同时应用rapamycin,分别采用流式细胞术和Hoechst33258荧光染色检测细胞凋亡率和形态学的变化,JC-1荧光染色观察线粒体膜电位(ΔΨm)变化,Western blotting法检测活性caspase-3蛋白表达水平。结果:STAT3-siRNA+Rapa组细胞凋亡率为60.22%±0.87%,明显高于其他各组(P<0.05),且细胞ΔΨm明显降低(27.28%±1.82%,P<0.05);Hoechst33258荧光染色检测,见STAT3-siRNA有大量细胞出现细胞核聚集、边缘化和核碎裂等典型细胞凋亡形态;Western blotting检测,STAT3-siRNA+Rapa组活性caspase-3蛋白表达水平明显高于其他各组(P<0.05)。结论:RNAi沉默BEL-7402肝癌细胞STAT3基因联合rapamycin可促进BEL-7402肝癌细胞的凋亡,二者具有明显的协同作用。

RAPAMYCIN产生菌SIIA9268的分类与鉴定

从我国湖北省武汉东湖土壤中分离到一株链霉菌，编号ＳＩＩＡ９２６８，其代谢产物具有免疫抑制作用，经鉴别活性物质与Ｒａｐａｍｙｃｉｎ为同一物质。该菌株在形态培养特征和生理生化特征上与已知的吸水链霉菌相似，但又有一定的差别，故定名为吸水链霉菌东湖变种（Ｓｔｒｅｐｔｏ－ｍｙｃｅｓｈｙｇｒｏｓｃｏｐｉｃｕｓｄｏｎｇｈｕｅｎｓｉｓＳＩＩＡ９２６８）。

Rapamycin药物涂层支架在冠心病中的临床应用

目的:探讨Rapamycin涂层支架临床应用的安全性和有效性。方法:25例冠心病患者行Rapamycin涂层支架植入术为药物支架组,12例行普通支架植入的患者为普通支架组,分别记录两组一般情况、术中支架植入情况以及随访结果,并比较两组的临床应用情况。结果:药物支架组合并高血压病和糖尿病及高LP(a)者明显多于普通支架组。药物支架组在左前降支植入者20例,占80%,普通支架组左前降支植入者5例,占41.67%;药物支架植入的血管直径较普通支架为小(P<0.05,P<0.01),而最大扩张压力和扩张时间在药物支架组明显高于普通支架组。结论:Rapamycin涂层支架植入是安全有效的介入手术,在防治PTCA支架术后再狭窄方面有良好的应用前景。

Neuroprotective effects of rapamycin on spinal cord injury in rats by increasing autophagy and Akt signaling

Rapamycin treatment has been shown to increase autophagy activity and activate Akt phosphorylation, suppressing apoptosis in several models of ischemia reperfusion injury. However, little has been studied on the neuroprotective effects on spinal cord injury by activating Akt phosphorylation. We hypothesized that both effects of rapamycin, the increased autophagy activity and Akt signaling, would contribute to its neuroprotective properties. In this study, a compressive spinal cord injury model of rat was created by an aneurysm clip with a 30 g closing force. Rat models were intraperitoneally injected with rapamycin 1 mg/kg, followed by autophagy inhibitor 3-methyladenine 2.5 mg/kg and Akt inhibitor IV 1 μg/kg. Western blot assay, immunofluorescence staining and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling assay were used to observe the expression of neuronal autophagy molecule Beclin 1, apoptosis-related molecules Bcl-2, Bax, cytochrome c, casp ase-3 and Akt signaling. Our results demonstrated that rapamycin inhibited the expression of mTOR in injured spinal cord tissue and up-regulated the expression of Beclin 1 and phosphorylated-Akt. Rapamycin prevented the decrease of bcl-2 expression in injured spinal cord tissue, reduced Bax, cytochrome c and caspase-3 expression levels and reduced the number of apoptotic neurons in injured spinal cord tissue 24 hours after spinal cord injury. 3-Methyladenine and Akt inhibitor IV intervention suppressed the expression of Beclin-1 and phosphorylated-Akt in injured spinal cord tissue and reduced the protective effect of rapamycin on apoptotic neurons. The above results indicate that the neuroprotective effect of rapamycin on spinal cord injury rats can be achieved by activating autophagy and the Akt signaling pathway.

Immunosuppressive potency of mechanistic target of rapamycin inhibitors in solid-organ transplantation

Mammalian target of rapamycin, also known as me-chanistic target of rapamycin(m TOR) is a protein kinase that belongs to the PI3K/AKT/m TOR signaling pathway, which is involved in several fundamental cellular functions such as cell growth, proliferation, and survival. This protein and its associated pathway have been implicated in cancer development and the regulation of immune responses, including the rejection response generated following allograft transplantation. Inhibitors of m TOR(m TORi) such as rapamycin and its derivative everolimus are potent immunosuppressive drugs that both maintain similar rates of efficacy and could optimize the renal function and diminish the side effects compared with calcineurin inhibitors. These drugs are used in solid-organ transplantationtoinduceimmunosuppression while also promoting the expansion of CD4+CD25+FOXP3+ regulatory T-cells that could favor a scenery of immu-nological tolerance. In this review, we describe the mechanisms by which inhibitors of m TOR induce sup-pression by regulation of these pathways at different levels of the immune response. In addition, we par-ticularly emphasize about the main methods that are used to assess the potency of immunosuppressive drugs, highlighting the studies carried out about immunosuppressive potency of inhibitors of m TOR.

Adenosine triphosphate promotes locomotor recovery after spinal cord injury by activating mammalian target of rapamycin pathway in rats

The mammalian target of rapamycin （mTOR） pathway plays an important role in neuronal growth, proliferation and differentiation. To better understand the role of mTOR pathway involved in the induction of spinal cord injury, rat models of spinal cord injury were established by modified Allen＇s stall method and interfered for 7 days by intraperitoneal administration of mTOR activator adenosine triphosphate and mTOR kinase inhibitor rapamycin. At 1-4 weeks after spinal cord injury induction, the Basso, Beattie and Bresnahan locomotor rating scale was used to evaluate rat locomotor function, and immunohistochemical staining and western blot analysis were used to detect the expression of nestin （neural stem cell marker）, neuronal nuclei （neuronal marker）, neuron specific enolase, neurofilament protein 200 （axonal marker）, glial fibrillary acidic protein （astrocyte marker）, Akt, mTOR and signal transduction and activator of transcription 3 （STAT3）. Results showed that adenosine triphosphate-mediated Akt/mTOR/STAT3 pathway increased endogenous neural stem cells, induced neurogenesis and axonal growth, inhibited excessive astrogliosis and improved the locomotor function of rats with spinal cord injury.

免疫抑制剂Rapamycin的研究进展

新型免疫抑制剂Ｒａｐａｍｙｃｉｎ具有优于环孢菌素、ＦＫ５０６的免疫抑制活性。它能抑制生长因子或细胞因子引起的细胞增殖。动物实验表明它对急、慢性排斥反应、加速移植排斥反应、移植物抗宿主病等均有其独到的疗效。此外它也可用于多种实验性自身免疫病的治疗。本文就Ｒａ－ｐａｍｙｃｉｎ的体内外免疫抑制作用特点，作用机制及毒副反应等研究进展作简要介绍。

Combination of Rapamycin and Imatinib in Treating Refractory Chronic Myeloid Leukemia Myeloid Blast Crisis:a Case Report

HRONIC myeloid leukemia （CML） is characterized by the presence of the BCR/ABL fusion gene, which is the result of a reciprocal translo cation between chromosomes 9 and 22, calledPhiladelphia （Ph） chromosome. Imatinib mesylate （imatinib）, a specific small molecular inhibitor of BCR/ABL, could improve the prognosis of CML and is now the standard drug applied in all phases of this disease} Despite the efficacy of imatinib, the development of resistance and the persistence of minimal residual disease have seriously impaired the efficiency of this medicine. Resistance may develop through several different mechanisms, such as mutations in the Abl kinase domain, BCR/ABL overexpression, or compensatory phosphatidylinositol 3 kinase （PI3K）/Akt/ mammalian target of rapamycin （mTOR） activation.2,3 Rapamycin, with mTOR as a potential therapeutic target, has been studied in patients with hematologic malignancies. Here we report a case of refractory CML myeloid blast crisissuccessfully treated by the combination of rapamycin and imatinib.

Role of mammalian target of rapamycin complex 2 in primary and secondary liver cancer

The mammalian target of rapamycin(mTOR)acts in two structurally and functionally distinct protein complexes,mTOR complex 1(mTORC1)and mTOR complex 2(mTORC2).Upon deregulation,activated mTOR signaling is associated with multiple processes involved in tumor growth and metastasis.Compared with mTORC1,much less is known about mTORC2 in cancer,mainly because of the unavailability of a selective inhibitor.However,existing data suggest that mTORC2 with its two distinct subunits Rictor and mSin1 might play a more important role than assumed so far.It is one of the key effectors of the PI3K/AKT/mTOR pathway and stimulates cell growth,cell survival,metabolism,and cytoskeletal organization.It is not only implicated in tumor progression,metastasis,and the tumor microenvironment but also in resistance to therapy.Rictor,the central subunit of mTORC2,was found to be upregulated in different kinds of cancers and is associated with advanced tumor stages and a bad prognosis.Moreover,AKT,the main downstream regulator of mTORC2/Rictor,is one of the most highly activated proteins in cancer.Primary and secondary liver cancer are major problems for current cancer therapy due to the lack of specific medical treatment,emphasizing the need for further therapeutic options.This review,therefore,summarizes the role of mTORC2/Rictor in cancer,with special focus on primary liver cancer but also on liver metastases.

Rapamycin增强上皮性卵巢癌细胞株对顺铂的敏感性研究

目的比较单独mTOR抑制剂Rapamycin、单独顺铂或联合2种制剂对上皮性卵巢癌SKOV3、ES-2细胞增殖和凋亡的影响。方法采用Westernblot检测Rapamycin对mTOR的抑制效应,检测顺铂对mTOR信号通路的影响度。采用单独Rapamycin、单独顺铂或联合2种制剂作用于上皮性卵巢癌SKOV3和ES-2细胞,运用MTT和FCM比较不同治疗方案对其增殖和凋亡的影响。结果在正常培养条件下,100nmol/LRapamycin作用24h,上皮性卵巢癌细胞内p-mTOR表达显著抑制;顺铂可影响上皮性卵巢癌ES-2细胞mTOR信号通路的激活情况;与单独顺铂作用和单独Rapamycin作用比较,联合两种制剂显著增加SKOV3和ES-2细胞的早期凋亡率,抑制细胞增殖(P均<0.05)。结论mTOR信号通路在上皮性卵巢癌顺铂化疗中发挥调节作用,Rapamycin可通过抑制mTOR激活而增强顺铂的杀伤作用。