Impact of L-type amino acid transporter 1 on intrahepatic cholangiocarcinoma.

BACKGROUND: Amino acid transporters, such as L-type amino acid transporter 1 (LAT1), have an effect on tumor growth, metastasis, and survival of various solid tumors. However, the role of LAT1 in patients with intrahepatic cholangiocarcinoma (IHCC) remains unknown. METHODS: Forty-six patients who had undergone initial hepatic resection for IHCC at Tokushima University Hospital were enrolled in this study. Immunohistochemical analysis of LAT1 and phosphorylated Akt (p-AKT) was performed using resected specimens. Clinicopathological factors, including prognosis, were analyzed between LAT1-high and LAT1-low groups. RESULTS: The LAT1-high group showed a higher proportion of periductal infiltrating type and higher carcinoembryonic antigen/carbohydrate antigen 19-9 levels compared with the LAT1-low group. Multivariate analysis revealed that LAT1-high expression was an independent prognostic factor for disease-free survival. Furthermore, the proportion of p-AKT positivity was higher in the LAT1-high group than in the LAT1-low group. CONCLUSIONS: LAT1 expression was associated with poor prognosis of IHCC and higher p-Akt expression. J. Med. Invest. 70 : 160-165, February, 2023.

Netrin-1 attenuates cerebral ischemia/reperfusion injury by limiting mitochondrial ROS and Ca2+ levels via activation of AKT phosphorylation and mitochondrial m-AAA protease AFG3L2.

Cerebral ischemia-reperfusion (I/R) injury as the consequence of revascularization after ischemic stroke is associated with mitochondrial dysfunction, oxidative stress, and neuron loss. In this study, we used a deprivation/reoxygenation (OGD/R) model to determine whether interactions between Netrin-1, AKT, and the mitochondrial AAA protease AFG3L2 could influence mitochondrial function in neurons after I/R. We found that Netrin-1 protects primary cortical neurons from OGD/R-induced cell death and regulates mitochondrial reactive oxygen species (ROS) and Ca2+ levels. The accumulation of mitochondrial calcium uniporter (MCU) subunits was monitored in cells by immunoblot analysis. Although the regulatory subunits MICU1 and MICU2 were relatively unaffected, the accumulation of the essential MCU regulator (EMRE) subunit was impaired. In OGD/R-induced cells, the 7 kDa form of EMRE was significantly reduced. Netrin-1 inhibited the accumulation of EMRE and mitochondrial Ca2+ levels by upregulating AFG3L2 and AKT activation. Loss of AFG3L2 or inhibition of AKT increased levels of 7 kDa EMRE. Moreover, overexpression of AKT increased the expression of AFG3L2 in Netrin-1-knockdown neurons after OGD/R. Our results demonstrate that Netrin-1 enhanced AFG3L2 protein expression via activation of AKT. We also observed that overexpression of Netrin-1 significantly reduced infarction size in an I/R-induced brain injury model in rats but not when AKT was inhibited. Our data suggest that AFG3L2 is a protein substrate of AKT and indicate that Netrin-1 attenuates cerebral I/R injury by limiting mitochondrial ROS and Ca2+ levels through activating AKT phosphorylation and AFG3L2.

Achievement of a durable response with eribulin for relapsed cardiac metastasis of uterine leiomyosarcoma after surgery: a case report and literature review.

BACKGROUND: Uterine leiomyosarcoma (U-LMS) is an aggressive malignancy linked to a high risk of metastasis to distant major organs. Although cardiac metastasis of U-LMS is extremely rare, it is often associated with life-threatening conditions, leading to dismal prognosis. Currently, there is no established therapy for patients with unresectable/relapsed cardiac metastasis of U-LMS. In this article, we report a case of locally relapsed cardiac metastasis of U-LMS, which occurred 3 years after surgical resection, successfully treated with eribulin. CASE DESCRIPTION: A 69-year-old female with cardiac symptoms (e.g., dyspnea, tachycardia, and easy fatigability) was sequentially treated with doxorubicin plus ifosfamide, gemcitabine plus docetaxel, and pazopanib. However, cardiac metastasis continued to grow despite treatment. Hence, eribulin was administered as fourth-line therapy. Exceptionally, eribulin markedly improved cardiac symptoms, and the patient achieved a durable response for 17 months without the development of severe adverse events. Moreover, the volume of the metastatic cardiac tumor was decreased by 70%. Despite the poor prognosis of this condition, the patient survived for 8 years from the diagnosis of cardiac metastasis due to surgery and the continuous administration of chemotherapies. CONCLUSIONS: Eribulin may be an effective and accessible treatment option for cardiac metastasis of U-LMS in patients with life-threatening conditions for whom surgery is not indicated. Additionally, the expression levels of phosphorylated AKT (p-AKT) may be a predictive biomarker for the sensitivity of patients with U-LMS to treatment with eribulin.

Complete Response to Eribulin in a Patient with Unresectable Liposarcoma: A Case Report and Implications of New Biomarkers.

We herein report a rare case of unresectable liposarcoma that showed a complete response to eribulin. Furthermore, a low expression of phosphorylated AKT (p-AKT) on an immunohistological evaluation was observed. This result is consistent with our previous preclinical study that demonstrated the significance of p-AKT signaling for eribulin resistance in multiple subtypes of soft tissue sarcoma (STS) cells. This case highlights the potential benefits of eribulin as well as the mechanism underlying resistance to eribulin in patients with unresectable or metastatic STS, especially liposarcoma.

Significance and expression of p-Akt in oral squamous cell carcinoma.

Background: Oral cancer is considered as the sixth-most common malignant neoplasm in the world and the most common type is squamous cell carcinoma (SCC). Akt is a serine/threonine-protein kinase, that acts in the regulation of different signaling downstream pathways, including; proliferation, growth, cell metabolism, angiogenesis and survival. The objective of the present study was to show the expression of p-Akt and its prognostic effect in oral SCC (OSCC). Materials and Methods: A total of 72 cases of OSCC were included in this study; the expression of the Akt gene was done on 4 µm tumor sections using immunohistochemical staining of Akt antibody. Results: Histopathological examination showed that: (43) were GIII, (13) cases were GII, and (16) cases were GI. The positivity of immunohistochemical staining were appear as brown stain. Results showed increase expression of p-Akt in most cases of oral SCC and mean expression about (54.86 ± 31.58), and the expression of p-Akt was increased with the progression of the histological grade of the tumor. Conclusion: High expression of p-Akt and its relation with the progression of tumor grade and invasion of tumor may indicate the relationship between p-Akt expression and aggressiveness and progression of the tumor.

Efficacy of a Novel Oral Chemotherapeutic Agent, TAS-102, Against Human Oral Squamous Cell Carcinoma Cells.

BACKGROUND: TAS-102 is effective against unresectable advanced or recurrent colorectal and gastric cancer. However, its effect on oral squamous cell carcinoma (OSCC) is still unknown. Here, we tried to clarify the possible effect of TAS-102 against angiogenesis and proliferation of human OSCC cells. MATERIALS AND METHODS: 3-(4,5-Dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay, migration assay and mice xenograft models were used to determine the effect of TAS-102 on growth and migration of OSCC. The activity of phosphorylated nuclear factor kappa light-chain-enhancer of activated B-cells (NF-κB) (p-p65) in cells was detected by immunocytochemistry. The expression of p-AKT serine/threonine kinase 1 (p-AKT), p-p65, vascular endothelial growth factor (VEGF), fibroblast growth factor (FGF2) and CD31 in mouse tumors were detected by immunohistochemistry. RESULTS: TAS-102 significantly inhibited growth and migration of OSCC both in vitro and in vivo. It suppressed the activity of NF-κB in cells. TAS-102 down-regulated the expression of p-AKT, VEGF, FGF2 and CD31, which was associated with reduced vascularization of HSC2 tumor lesions. CONCLUSION: These findings suggest that TAS-102 might inhibit angiogenesis and proliferation of OSCC cells.

Inhibitory effect of gefitinib derivative LPY­9 on human glioma.

The present study aimed to investigate the effects of a gefitinib derivative, LPY­9, on the proliferation, apoptosis and migration of human glioma cell line U251­MG by CCK8, Transwell or flow cytometry, and the effect of LPY­9 on the activity of caspase­3 enzyme and related proteins in the vascular endothelial growth factor (VEGF) and epidermal growth factor receptor (EGFR) pathways by western blot and ELISA. It was found that LPY­9 exhibited higher a inhibitory effect on the proliferation of U251­MG cell lines compared with gefitinib and it also exhibited a certain dose­dependence. Following LPY­9 treatment, typical apoptotic morphology was observed under the microscope after Giemsa staining. LPY­9 induced apoptosis at low concentration, and the activity of caspase­3 enzyme increased with the increase in drug concentration, significantly inhibiting the secretion of VEGF in a dose­dependent manner. The effect was notably more evident compared with gefitinib at the same concentration. The expression level of caspase­3 and cleaved caspase­3 increased with the increase in LPY­9 concentration; however, expression levels of VEGF, EGFR, phosphorylated AKT and PI3K decreased with the increase of LPY­9 concentration and no change was observed in the expression level of AKT. LPY­9 inhibited the proliferation of the human glioma cell line U251­MG, promoted apoptosis and effectively inhibited the migration of U251­MG cells. The effect of LPY­9 was more noticeable compared with gefitinib. The results of the present study may provide a foundation for further study and clinical research of this as an anti­tumor drug in animal models.

Silencing the COPB2 gene decreases the proliferation, migration and invasion of human triple-negative breast cancer cells.

Triple-negative breast cancer (TNBC) is highly invasive, has a high rate of recurrence and is associated with a poor clinical outcome when compared with non-TNBC due to a lack of effective and targeted treatments. The coatomer protein complex subunit ß2 (COPB2) is upregulated in various types of malignant cancer. The present study demonstrated that COPB2 expression levels were significantly upregulated in breast carcinoma HS-578T cells (clonal cells originating from TNBC) when compared with non-TNBC MCF-7 cells. HS-578T cells also exhibited higher rates of proliferation, invasion and transendothelial migration when compared with MCF-7 cells. Moreover, it was identified that genetically silencing the COPB2 gene using a lentivirus-short hairpin RNA inhibited the proliferative, colony formation, migratory and invasive properties of the TNBC HS-578T cells. Mediation of the COPB2 silencing effect may be associated with regulating the phosphorylation of serine/threonine kinase AKT in the PI3K/AKT signaling pathway. These results suggested the importance of COPB2 in promoting the proliferation of TNBC cells and identified COPB2 as a potential novel therapeutic target.

Miltirone induces cell death in hepatocellular carcinoma cell through GSDME-dependent pyroptosis.

Pyroptosis is a form of programmed cell death, and recently described as a new molecular mechanism of chemotherapy drugs in the treatment of tumors. Miltirone, a derivative of phenanthrene-quinone isolated from the root of Salvia miltiorrhiza Bunge, has been shown to possess anti-cancer activities. Here, we found that miltirone inhibited the cell viability of either HepG2 or Hepa1-6 cells, and induced the proteolytic cleavage of gasdermin E (GSDME) in each hepatocellular carcinoma (HCC) cell line, with concomitant cleavage of caspase 3. Knocking out GSDME switched miltirone-induced cell death from pyroptosis to apoptosis. Additionally, the induction effects of miltirone on GSDME-dependent pyroptosis were attenuated by siRNA-mediated caspase three silencing and the specific caspase three inhibitor Z-DEVD-FMK, respectively. Miltirone effectively elicited intracellular accumulation of reactive oxygen species (ROS), and suppressed phosphorylation of mitogen-activated and extracellular signal-regulated kinase (MEK) and extracellular regulated protein kinases 1/2 (ERK1/2) for pyroptosis induction. Moreover, miltirone significantly inhibited tumor growth and induced pyroptosis in the Hepa1-6 mouse HCC syngeneic model. These results provide a new insight that miltirone is a potential therapeutic agent for the treatment of HCC via GSDME-dependent pyroptosis.

Identification of pAKT as a pharmacodynamic marker for MER kinase in human melanoma G361 cells.

BACKGROUND: The MER signaling pathway represents an attractive therapeutic target for human cancers. Growth arrest-specific protein 6 (GAS6)-induced MER phosphorylation is often unstable and difficult to detect without pervanadate pretreatment in human cancer cells, posing a challenge for the development of selective MER kinase inhibitors. Here, we identified phosphorylated AKT (pAKT) as a specific pharmacodynamic marker for MER kinase inhibitors in human melanoma G361 cells. METHODS: The expression of MER, TYRO3, and AXL were profiled among multiple human cancer cells. To determine whether they play a role in the activation of pAKT, MER and TYRO3 were selectively depleted by small, interfering RNA knockdown. In addition, using AKT phosphorylation as a readout, a high-throughput cell-based assay was established in G361 cells for evaluation of the potency of potential inhibitors of MER pathway activation. RESULTS: We demonstrated that high levels of MER and TYRO3, but not AXL, were expressed in G361 cells. In these cells, pAKT was induced by GAS6 treatment, which could be reversed by AXL/MER inhibitors. We showed that GAS6-induced pAKT is only dependent on MER kinase, but not TYRO3, in G361 cells. Furthermore, we observed a correlation in potency between inhibition of pAKT in G361 cells and pMER in MER-overexpressing Ba/F3 cells by these inhibitors. CONCLUSIONS: In summary, we have demonstrated that GAS6-induced pAKT is a possible pharmacodynamic marker for the inhibition of MER kinase, and we have successfully developed a cell-based functional assay for screening small-molecule inhibitors of MER kinase for potential therapeutic utility in treating GAS6/MER-deregulated human cancers.

Simultaneous Knockdown of Sprouty2 and PTEN Promotes Axon Elongation of Adult Sensory Neurons.

Sprouty2 (Spry2) and phosphatase and tensin homolog deleted on chromosome 10 (PTEN) are both well-established regulators of receptor tyrosine kinase (RTK) signaling, and knockdown of Spry2 or PTEN enhances axon regeneration of dorsal root ganglia (DRG) neurons. The major role of Spry2 is the inhibition of the rat sarcoma RAS/extracellular signal-regulated kinase (ERK) pathway, whereas PTEN acts mainly as an inhibitor of the phosphoinositide 3-kinase (PI3K)/Akt pathway. In non-neuronal cells, Spry2 increases the expression and activity of PTEN, and PTEN enhances the amount of Spry2 by the inhibition of the microRNA-21 (miR-21) that downregulates Spry2. Applying dissociated DRG neuron cultures from wild-type (WT) or Spry2 deficient mice, we demonstrate that PTEN protein was reduced after 72 h during rapid axonal outgrowth on the laminin substrate. Furthermore, PTEN protein was decreased in DRG cultures obtained from homozygous Spry2-/- knockout mice. Vice versa, Spry2 protein was reduced by PTEN siRNA in WT and heterozygous Spry2+/- neurons. Knockdown of PTEN in DRG cultures obtained from homozygous Spry2-/- knockout mice promoted axon elongation without increasing axonal branching. Activation of Akt, but not ERK, was stronger in response to PTEN knockdown in homozygous Spry2-/- DRG neurons than in WT neurons. Together, our study confirms the important role of the signaling modulators Spry2 and PTEN in axon growth of adult DRG neurons. Both function as endogenous inhibitors of neuronal growth factor signaling and their simultaneous knockdown promotes axon elongation more efficiently than the single knockdown of each inhibitor. Furthermore, Spry2 and PTEN are reciprocally downregulated in adult DRG neuron cultures. Axon growth is influenced by multiple factors and our results demonstrate that the endogenous inhibitors of axon growth, Spry2 and PTEN, are co-regulated in adult DRG neuron cultures. Together, our data demonstrate that combined approaches may be more useful to improve nerve regeneration than targeting one single inhibitor of axon growth.

Effects of fluvoxamine on nerve growth factor-induced neurite outgrowth inhibition by dexamethasone in PC12 cells.

In the present study, we examined the effects of fluvoxamine on nerve growth factor (NGF)-induced neurite outgrowth inhibition by dexamethasone (DEX) in PC12 cells. Fluvoxamine increased NGF-induced neurite outgrowth. Compared with co-treatment with NGF and fluvoxamine, p-Akt levels were higher than the values without fluvoxamine. The phosphorylated extracellular regulated kinase 1/2 levels were slightly increased by co-treatment with NGF and fluvoxamine. Fluvoxamine concentration-dependently improved NGF-induced neurite outgrowth inhibition by DEX. Fluvoxamine also improved the decrease in the NGF-induced p-Akt level caused by DEX. Interestingly, the sigma-1 receptor antagonist NE-100 blocked the improvement effects of fluvoxamine on NGF-induced neurite outgrowth inhibition by DEX. The selective sigma-1 receptor agonist PRE-084 also improved NGF-induced neurite outgrowth inhibition by DEX, which is blocked by NE-100. These results indicate that the improvement effects of fluvoxamine on NGF-induced neurite outgrowth inhibition by DEX may be attributable to the phosphorylation of Akt and the sigma-1 receptor.

The protective effect of quercetin on vascular endothelial progenitor cells by regulating PI3K/AKT signaling pathway and its mechanisms / 中国药理学通报

Aim To study the protective effect of quercetin ( Que) on vascular endothelial progenitor cells ( EPCs) under oxidative stress and the underlying mechanisms. Methods The human umbilical cord blood EPCs were separated .differentiated and randomized into two groups, namely, hydrogen peroxide (H202) group, in which the oxidative stress damage EPCs model was established by adding H202 of 500 jjunol • L"1 ,and Que intervention group,in which Que pretreated with a concentration of 60 jimol • L~' and 90 p.mol • L'1 was added for 30 min respectively, and then 500 jimol • L"1 H202 was added for co-culture. WST-1 method was used to assess the proliferation of EPCs after 12,24 and 48 h culture. Western blot was used to detect the expression levels of Akt and phos- phorylated Akt. Real-time fluorescence RT-PCR was employed to determine the expression levels of PI3K and AKT3 mRNA. Results Compared with blank control group,the proliferation capacity of EPCs treated with hydrogen peroxide was significantly reduced. The expression of Akt protein in EPCs decreased significantly, and the relative expression of PI3K and AKT3 mRNA decreased significantly ( P < 0. 01, P < 0. 05 ). After 60,90 jtmol • L"1 Que was added for 12,24 and 48 h,respectively,the proliferation capacity of damaged EPCs cells increased significantly, and the difference was statistically significant compared with the model group (fcO. 05). At the same time, the protein expression of p-Akt in EPCs significantly increased ( P < 0.05),and mRNA expression of PI3K and AKT3 increased ( P < 0. 01 ). Conclusions Que can fix the EPCs oxidative stress induced by H202 ,and its mecha-nism may be through the activation of PI3K/AKT signaling pathway, reducing the influence of oxidative stress on cerebrovascular lesions,and promoting the proliferation and differentiation of cerebrovascular EPCs.

DJ-1 promotes survival of human colon cancer cells under hypoxia by modulating HIF-1α expression through the PI3K-AKT pathway.

BACKGROUND: Protein/nucleic acid deglycase (DJ-1) and hypoxia-inducible factor-1α (HIF-1α) play significant roles in the progression of various types of cancer and are associated with the phosphatidylinositol 3-kinase (PI3K) pathway. However, their functions in colorectal cancer (CRC) have not been identified. The aim of this study was to analyze the putative signaling pathway encompassing DJ-1, PI3K, and HIF-1α in a series of CRC tissues and cell lines. PURPOSE: This study aimed at exploring the expression status of DJ-1 in colon cancer and its role in survival of cancer cell lines. METHODS: The expression and localization of DJ-1, PI3K-p110α, phosphorylated Akt (p-AKT), and HIF-1α were determined by immunohistochemistry in 73 resected CRC tissues. The effect of DJ-1 on cell activity was explored by in vitro knockdown and overexpression experiments in SW480 and HT-29 cells. The cells were treated with a PI3K inhibitor (LY294002 or wortmannin), and p-AKT and HIF-1α protein expression were then analyzed. Apoptosis was analyzed by flow cytometry. The expression levels of several HIF-1 target genes were assessed under hypoxic conditions by reverse transcription-PCR and Western blot. Xenograft tumor growth studies were conducted in DJ-1 knockdown or overexpression cells. RESULTS: High DJ-1 expression was found in 68.49% (50/73) of CRC tissues and associated with larger tumor size and advanced clinical stages. DJ-1 expression was positively associated with PI3K-p110α, p-AKT, and HIF-1α expression in CRC. HIF-1α and p-AKT protein levels were lower in SW480 and HT-29 cells with stable DJ-1 knockdown than in those with DJ-1 overexpression. PI3K inhibitors almost completely blocked DJ-1-induced AKT phosphorylation. However, the expression of HIF-1α was partially preserved after treatment with PI3K inhibitors. We also show that DJ-1 is necessary for the transcriptional ability of HIF-1α and CRC cell survival after hypoxic stress. Moreover, DJ-1 promoted the growth of established tumor xenografts in nude mice. CONCLUSION: Our findings are the first to show that DJ-1 is overexpressed in CRC. We suggest a model in which DJ-1 mediates CRC cell survival by regulating the PI3K-AKT-HIF-1α pathway.

MiR-1260b inhibitor enhances the chemosensitivity of colorectal cancer cells to fluorouracil by targeting PDCD4/IGF1.

Colorectal cancer (CRC) is the most common malignant tumor type and has become resistant to 5-fluorouracil (5-FU) in recent decades, which is one of the most popular therapies. Recently, microRNA (miRNA or miR) has been investigated as a potential therapeutic strategy for CRC. However, there has been little investigation of the underlying mechanism of the association between expression of miRNA and chemosensitivity. The present study aimed to investigate the effect of miR-1260b inhibitor on CRC cells, and their chemosensitivity to 5-FU, by treating them with the miR-1260b inhibitor. miR-1260b inhibitor was demonstrated to significantly promote the proliferation and invasion of the CRC cell line, HCT116, and to increase the apoptotic rate. Furthermore, it was validated that programmed cell death 4 (PDCD4) was a direct target of miR-1260b inhibitor in CRC with bioinformatics tools and a luciferase assay. Western blot analysis revealed that miR-1260b inhibitor could significantly decrease PDCD4 expression, and downregulate the expression of phosphorylated-Akt (p-Akt) and phosphorylated-extracellular-signal-regulated kinase (p-ERK). In conclusion, it was confirmed that the anti-tumor effect of the miR-1260b inhibitor was conducted by blocking the phosphorylated 3-kinase/Akt pathway as dysregulated protein expression induced by miR-1260b inhibitor was rescued by insulin-like growth factor. Notably, miR-1260b inhibitor could significantly enhanced the chemoresponse of HCT116 cells to 5-FU via reduced proliferation, increased apoptosis, and downregulation of PDCD4, p-Akt and p-ERK protein expression. In summary, the present study may provide a novel direction for future clinical therapy to enhance the chemosensitivity of tumor cells.

Downregulation of lncRNA H19 inhibits migration and invasion of human osteosarcoma through the NF-κB pathway.

The present study aimed to investigate the role of long non-coding RNA (lncRNA) H19 in the development of osteosarcoma and to determine the underlying mechanism involved. A total of 40 patients with osteosarcoma were selected and the expression level of H19 in tumor tissue and adjacent healthy tissue was detected by reverse transcription­quantitative polymerase chain reaction. Survival curves were plotted using the Kaplan­Meier method to investigate the prognostic value of H19 expression level for patients with osteosarcoma. H19 knockdown osteosarcoma cell lines were constructed using small interfering (si)RNA transfection. Cell migration and invasion abilities were measured by Transwell migration and invasion assays, respectively. Western blot analysis was performed to detect the expression levels of phosphatidylinositol 3­kinase (PI3K), phospho (p)­PI3K, RAC­alpha serine/threonine­protein kinase (AKT), p­AKT and NF­κB inhibitor α (IκBα) in osteosarcoma cells transfected with H19 siRNA. Expression level of H19 was significantly elevated in tumor tissue compared with adjacent healthy tissue. Expression level of H19 was positively associated with distant metastasis of osteosarcoma (P<0.01), but not with gender and age. Overall survival of patients with osteosarcoma with high H19 level was significantly shorter compared with patients with low H19 expression (P<0.05). H19 knockdown significantly reduced migration and invasion ability of osteosarcoma cells. Significantly decreased levels of p­PI3K and p­AKT, and elevated level of IκBα were observed in H19 knockdown osteosarcoma cells compared with control osteosarcoma cells, while no significant differences in levels of PI3K and AKT were observed. Therefore, the present study demonstrated that knockdown of lncRNA H19 can inhibit migration and invasion of human osteosarcoma cells by inhibiting the nuclear factor-κB pathway.

Leucine promotes differentiation of porcine myoblasts through the protein kinase B (Akt)/Forkhead box O1 signalling pathway.

Leucine, one of the branched-chain amino acids, is the only amino acid to regulate protein turnover in skeletal muscle. Leucine not only increases muscle protein synthesis, but also decreases muscle protein degradation. It is well documented that leucine plays a positive role in differentiation of murine muscle cells. However, the role of leucine on porcine myoblast differentiation and its mechanism remains unclear. In this study, porcine myoblasts were induced to differentiate with differentiation medium containing different concentrations of leucine, and wortmannin was used to interdict the activity of protein kinase B (Akt). We found that leucine increased the number of myosin heavy chain-positive cells and creatine kinase activity. Moreover, leucine increased the mRNA and protein levels of myogenin and myogenic determining factor (MyoD). In addition, leucine increased the levels of phosphorylated Akt/Akt and phosphorylated Forkhead box O1 (P-FoxO1)/FoxO1, as well as decreased the protein level of FoxO1. However, wortmannin, a specific repressor of PI3K/Akt signalling pathway, attenuated the positive role of leucine on porcine myoblast differentiation. Our results suggest that leucine promotes porcine myoblast differentiation through the Akt/FoxO1 signalling pathway.

Pathogenic Role of mTORC1 and mTORC2 in Pulmonary Hypertension.

Concentric lung vascular wall thickening due to enhanced proliferation of pulmonary arterial smooth muscle cells is an important pathological cause for the elevated pulmonary vascular resistance reported in patients with pulmonary arterial hypertension. We identified a differential role of mammalian target of rapamycin (mTOR) complex 1 and complex 2, two functionally distinct mTOR complexes, in the development of pulmonary hypertension (PH). Inhibition of mTOR complex 1 attenuated the development of PH; however, inhibition of mTOR complex 2 caused spontaneous PH, potentially due to up-regulation of platelet-derived growth factor receptors in pulmonary arterial smooth muscle cells, and compromised the therapeutic effect of the mTOR inhibitors on PH. In addition, we describe a promising therapeutic strategy using combination treatment with the mTOR inhibitors and the platelet-derived growth factor receptor inhibitors on PH and right ventricular hypertrophy. The data from this study provide an important mechanism-based perspective for developing novel therapies for patients with pulmonary arterial hypertension and right heart failure.

A nomogram based on phosphorylated AKT1 for predicting locoregional recurrence in patients with oesophageal squamous cell carcinoma.

Background: The AKT signalling pathway controls survival and growth in many malignant tumours. However, the prognostic value of phosphorylated AKT1 (p-AKT1) for locoregional-progression free survival (LPFS) in oesophageal squamous cell carcinoma (ESCC) has not been established. Our aim was to develop a nomogram to predict local recurrence using p-AKT1 and main clinical characteristics in patients with thoracic ESCC undergoing radical three-field lymph node dissection. Methods: Immunohistochemistry was performed to examine p-AKT1 expression in 181 thoracic ESCC patients. The Kaplan-Meier method was used to calculate LPFS. Cox regression analysis was also performed to evaluate prognostic factors. A nomogram comprising biological and clinical factors was established to predict LPFS. Results: The 5-year LPFS rate was 63.9%. Multivariate analysis revealed that expression of p-AKT1 (p<0.001), pathologic N category (p=0.004) and number of lymph nodes retrieved (p=0.001) were independent prognostic factors for LPFS. Increased expression of p-AKT1 was associated with decreased LPFS in patients with ESCC. In addition, a nomogram was established based on all significant independent factors for locoregional recurrence risk. Harrell's c-index for predicting LPFS was 0.78. Conclusion: Activation of AKT1 was associated with poor locoregional control in ESCC patients. The nomogram, based on p-AKT1 expression and clinically significant parameters, could be used as an accurate stratification model for predicting locoregional recurrence in patients with ESCC after radical resection.