Application of a Biphasic Mathematical Model of Cancer Cell Drug Response for Formulating Potent and Synergistic Targeted Drug Combinations to Triple Negative Breast Cancer Cells

Triple negative breast cancer is a collection of heterogeneous breast cancers that are immunohistochemically negative for estrogen receptor, progesterone receptor, and ErbB2 (due to deletion or lack of amplification). No dominant proliferative driver has been identified for this type of cancer, and effective targeted therapy is lacking. In this study, we hypothesized that triple negative breast cancer cells are multi-driver cancer cells, and evaluated a biphasic mathematical model for identifying potent and synergistic drug combinations for multi-driver cancer cells. The responses of two triple negative breast cancer cell lines, MDA-MB-231 and MDA-MB-468, to a panel of targeted therapy drugs were determined over a broad range of concentrations. The analyses of the drug responses by the biphasic mathematical model revealed that both cell lines were indeed dependent on multiple drivers, and inhibitors of individual drivers caused a biphasic response: a target-specific partial inhibition at low nM concentrations, and an off-target toxicity at μM concentrations. We further demonstrated that combinations of drugs, targeting each driver, cause potent, synergistic, and cell-specific cell killing. Immunoblotting analysis of the effects of the individual drugs and drug combinations on the signaling pathways supports the above conclusion. These results support a multi-driver proliferation hypothesis for these triple negative breast cancer cells, and demonstrate the applicability of the biphasic mathematical model for identifying effective and synergistic targeted drug combinations for triple negative breast cancer cells.

Stavudine exposure results in developmental abnormalities by causing DNA damage, inhibiting cell proliferation and inducing apoptosis in mouse embryos

Stavudine is an anti-AIDS drug widely used to prevent HIV transmission from pregnant mothers to the fetuses in underdeveloped countries for its low price. However, there is still a controversy on whether stavudine affects embryo development. In the current study, embryotoxicity of stavudine was evaluated using cultured mouse embryos with the concentrations: 5, 10, 15 μM and vehicle control. The data indicated that the effect of stavudine was dose-dependent at early neurogenesis. Stavudine exposure reduced somite numbers, yolk sac diameter, crown-rump length, and increased the rate of embryonic degeneration compared with the control. We chose the lowest but clearly toxic concentration: 5 μM to investigate the molecular mechanisms of the damage. At the molecular level, stavudine produced DNA damage, increased the levels of the phospho-CHK1 and cleaved-caspase-3, and decreased the expression level of proliferating cell nuclear antigen. These changes indicated that stavudine caused a coordinated DNA damage response, inhibited cell proliferation, and induced apoptosis in the embryos. Collectively these results suggest that stavudine exposure disturbs the embryonic development, and its use in pregnant mothers should be re-examined.

Molecular basis for receptor tyrosine kinase A-loop tyrosine transphosphorylation

A long-standing mystery shrouds the mechanism by which catalytically repressed receptor tyrosine kinase domains accomplish transphosphorylation of activation loop (A-loop) tyrosines. Here we show that this reaction proceeds via an asymmetric complex that is thermodynamically disadvantaged because of an electrostatic repulsion between enzyme and substrate kinases. Under physiological conditions, the energetic gain resulting from ligand-induced dimerization of extracellular domains overcomes this opposing clash, stabilizing the A-loop-transphosphorylating dimer. A unique pathogenic fibroblast growth factor receptor gain-of-function mutation promotes formation of the complex responsible for phosphorylation of A-loop tyrosines by eliminating this repulsive force. We show that asymmetric complex formation induces a more phosphorylatable A-loop conformation in the substrate kinase, which in turn promotes the active state of the enzyme kinase. This explains how quantitative differences in the stability of ligand-induced extracellular dimerization promotes formation of the intracellular A-loop-transphosphorylating asymmetric complex to varying extents, thereby modulating intracellular kinase activity and signaling intensity.

Association of growth traits with a structural variation downstream of the KCNJ11 gene: a large population-based study in chickens

1. The potassium voltage-gated channel subfamily J member 11 gene (KCNJ11) is involved in the insulin secretion pathway. Studies have shown that mutation in this gene is associated with muscle weakness. The objective of the present study was to establish the association between KCNJ11 gene polymorphism and chicken growth performance and to analyse its expression pattern. 2. A novel 163-bp insertion/deletion (indel) polymorphism was identified in the region downstream of the KCNJ11 gene in 2330 individuals from ten populations by polymerase chain reaction (PCR). An F₂ resource population was used to investigate the genetic effects of the chicken KCNJ11 gene. Association analysis showed that the indel was significantly associated with chicken growth traits and that the phenotypic value of the ins-ins (II) genotype is higher than that of the ins-del (ID) and del-del (DD) genotypes. 3. Gene expression for different genotypes showed that birds carrying the II allele had a higher expression level than the DD genotypes. Analysis of tissue and spatiotemporal expression patterns indicated that the KCNJ11 gene was highly expressed in muscle tissues, with the highest levels in muscle tissue at one week of age, and that a 10% crude protein diet reduced the expression of this gene, average daily gain and muscle fibre diameter. 4. The results suggested that this novel 163-bp indel has the potential to become a new target for marker-assisted selection.

Biphasic Mathematical Model of Cell-Drug Interaction That Separates Target-Specific and Off-Target Inhibition and Suggests Potent Targeted Drug Combinations for Multi-Driver Colorectal Cancer Cells

Quantifying the response of cancer cells to a drug, and understanding the mechanistic basis of the response, are the cornerstones for anti-cancer drug discovery. Classical single target-based IC₅₀ measurements are inadequate at describing cancer cell responses to targeted drugs. In this study, based on an analysis of targeted inhibition of colorectal cancer cell lines, we develop a new biphasic mathematical model that accurately describes the cell–drug response. The model describes the drug response using three kinetic parameters: ratio of target-specific inhibition, F₁, potency of target-specific inhibition, K_d1, and potency of off-target toxicity, K_d2. Determination of these kinetic parameters also provides a mechanistic basis for predicting effective combination targeted therapy for multi-driver cancer cells. The experiments confirmed that a combination of inhibitors, each blocking a driver pathway and having a distinct target-specific effect, resulted in a potent and synergistic blockade of cell viability, improving potency over mono-agent treatment by one to two orders of magnitude. We further demonstrate that mono-driver cancer cells represent a special scenario in which F₁ becomes nearly 100%, and the drug response becomes monophasic. Application of this model to the responses of >400 cell lines to kinase inhibitor dasatinib revealed that the ratio of biphasic versus monophasic responses is about 4:1. This study develops a new mathematical model of quantifying cancer cell response to targeted therapy, and suggests a new framework for developing rational combination targeted therapy for colorectal and other multi-driver cancers.

Cloning and expression analysis of PRL and PRLR genes in black Muscovy duck

1. Prolactin hormone (governed by the PRL gene) is secreted by the anterior pituitary of animals, which combines with its receptor (prolactin receptor, PRLR) to act on target cells. Both PRL and PRLR are mainly associated with reproductive performance. The genetic mechanism of nesting in poultry is not yet clear, and so the aim of the current study was to determine expression patterns of PRL and PRLR at different times across the breeding stages of black Muscovy ducks.2. In this study, the CDS regions of PRL and PRLR were determined by RACE sequencing. The expression levels of PRL and PRLR in the pituitary, ovary and uterus from the black Muscovy duck were compared and analysed during the pre-laying, laying and nesting periods.3. The results showed that PRL and PRLR are highly homologous in a variety of poultry species. The expression of the PRL gene in the pituitary was the highest, which was significantly higher than seen in the ovary and uterus. This trend ran through the entire prenatal period, i.e. the laying period and the nesting period. The expression level of the PRLR gene in the pituitary and ovary was generally low, and expression in the uterus was the highest. There was no significant difference in expression of the PRLR gene between pituitary and ovary during different periods, but the expression level of the PRLR gene in the uterus reached its highest level during the nesting stage, which was significantly higher than seen in the early laying period.

[Brain protection strategy and effectivity in pulmonary thromboendarterectomy]

Objective: To summarize the experience and effectivity of brain protection in 25 patients who suffered from chronic thromboembolic pulmonary hypertension (CTEPH) and received pulmonary thromboendarterectomy (PTE) under deep hypothermic circulatory arrest. Methods: Retrospective analysis of 25 PTE surgeries in our center from December 2016 to August 2018. All cases were completed underdeep hypothermic circulatory arrest. Standard brain protections were strictly executed, including: balanced and controlled extracorporeal circulation cooling, cerebral oxygen saturation (rSO(2)) monitoring, strictly control of circulatory arrest time, and etc. The neurological adverse events during the perioperative period were recorded and statistically analyzed, and the intelligence level and cognitive function of the patients were evaluated by MMSE scale and MoCA scale before surgery and discharge. Results: All the 25 patients successfully completed the surgery, and 1 patient (4%) died of postoperative infection. The mean pulmonary arterial pressure decreased from (52.9±16.7) mmHg before surgery to (23.6±8.1) mmHg immediately after surgery (t=10.01, P<0.01), and(20.7±7.9) mmHg at 3 months follow-up (t=10.73, P<0.01). Pulmonary vascular resistance decreased from 975.4 (788.6-1 292.8) dyn·s·cm(-5) to 376.1 (283.6-565.5) dyn·s·cm(-5) (Z=5.34, P<0.01). Neurological complications occurred in 3 patients during the perioperative period, including 2 patients with hypoxic encephalopathy, and 1 patient with cerebral hemorrhage. All 3 patients fully recovered before discharge. Univariate analysis showed that the duration of rSO(2)<40% and the maximum decrease rate of rSO(2) from baseline were significantly correlated with postoperative neurological damage. Multivariate analysis showed only time of rSO(2)<40% was significantly correlated with postoperative neurological damage. There was no significant difference in MMSE and MoCA score before and after surgery (P>0.05). Conclusions: Adequate brain protection measures are essential to reduce the neurological complications of PTE surgery. Real-time intraoperative monitoring of rSO(2) and strict control of circulatory arrest time can further reduce the occurrence of neurological damage.

Golgi membrane protein GP73 modified-liposome mediates the antitumor effect of survivin promoter-driven HSVtk in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common types of cancer worldwide, and there is currently no effective therapeutic strategy in clinical practice. Gene therapy has great potential for decreasing tumor-induced mortality but has been clinically limited because of the lack of tumor-specific targets and insufficient gene transfer. The study of targeted transport of therapeutic genes in HCC treatment seems to be very important. In this study, we evaluated a gene therapy approach targeting HCC using the herpes simplex virus thymidine kinase/ganciclovir (HSVtk/GCV) suicide gene system in HCC cell lines and in an in vivo human HCC xenograft mouse model. GP73-modified liposomes targeted gene delivery to the tumor tissue, and the survivin promoter drove HSVtk expression in the HCC cells. Our results showed that the survivin promoter was specifically activated in tumor cells and HSVtk was expressed selectively in tumor cells. Combined with GCV treatment, HSVtk expression resulted in suppression of HCC cell proliferation via enhancing apoptosis. Moreover, tail vein injection of GP73-HSVtk significantly suppressed the growth of xenograft tumors through an apoptosis-dependent pathway and extended the survival of tumor-bearing mice without damaging the mice liver functions. Taken together, this study demonstrates an effective cancer-specific gene therapy strategy using the herpes simplex virus thymidine kinase/ganciclovir (HSVtk/GCV) suicide gene system for HCC that can be further developed for future clinical trials.

The histone H3 lysine-27 demethylase UTX plays a critical role in colorectal cancer cell proliferation

Background

Ubiquitously transcribed tetratricopeptide repeat, X chromosome (UTX) is an H3K27me3 demethylase, a permissive mark associated with active gene transcription. UTX has been linked to various human cancers. Colorectal cancer (CRC) ranks 3rd among the most common cancers worldwide. However, the role of UTX in colorectal cancer has rarely been reported.

Methods

RT-qPCR, immunoblotting assays (WB), and immunohistochemistry staining were conducted to explore the UTX expression levels in CRC tissues and surrounding normal tissues. CCK-8 assays, colony formation assays, and flow cytometry were also used to determine the potential role of UTX in CRC cell proliferation in vitro. A cell line-derived xenograft model was performed to determine on the role of UTX in HCT116 cell proliferation in vivo. The protein expression levels of UTX, KIF14, AKT, and GAPDH were examined by WB.

Results

Compared with surrounding normal tissues, UTX was upregulated in CRC tissues. Knockdown of UTX significantly inhibited proliferation and caused G0/G1 cell cycle arrest in CRC cell lines, and overexpression of UTX significantly promoted proliferation in CRC cells. Furthermore, knockdown of UTX significantly inhibited tumour growth in vivo. In addition, knockdown of UTX decreased the expression of KIF14 and pAKT and increased the expression of P21.

Conclusions

Our findings indicate that knockdown of UTX inhibits CRC cell proliferation and causes G0/G1 cell cycle arrest through downregulating expression of KIF 14 and pAKT. Thus, UTX may serve as a novel biomarker in CRC.

Effective Dimensionality Reduction for Visualizing Neural Dynamics by Laplacian Eigenmaps

With the development of neural recording technology, it has become possible to collect activities from hundreds or even thousands of neurons simultaneously. Visualization of neural population dynamics can help neuroscientists analyze large-scale neural activities efficiently. In this letter, Laplacian eigenmaps is applied to this task for the first time, and the experimental results show that the proposed method significantly outperforms the commonly used methods. This finding was confirmed by the systematic evaluation using nonhuman primate data, which contained the complex dynamics well suited for testing. According to our results, Laplacian eigenmaps is better than the other methods in various ways and can clearly visualize interesting biological phenomena related to neural dynamics.

Ponatinib Inhibits Proliferation and Induces Apoptosis of Liver Cancer Cells, but Its Efficacy Is Compromised by Its Activation on PDK1/Akt/mTOR Signaling

Ponatinib is a multi-target protein tyrosine kinase inhibitor, and its effects on hepatocellular carcinoma cells have not been previously explored. In the present study, we investigated its effects on hepatocellular carcinoma cell growth and the underlying mechanisms. Toward SK-Hep-1 and SNU-423 cells, ponatinib induces apoptosis by upregulation of cleaved caspase-3 and -7 and promotes cell cycle arrest in the G1 phase by inhibiting CDK4/6/CyclinD1 complex and phosphorylation of retinoblastoma protein. It inhibits the growth-stimulating mitogen-activated protein (MAP) kinase pathway, the phosphorylation of Src on both negative and positive regulation sites, and Jak2 and Stat3 phosphorylation. Surprisingly, it also activates the PDK1, the protein kinase B (Akt), and the mechanistic target of rapamycin (mTOR) signaling pathway. Blocking mTOR signaling strongly sensitizes cells to inhibition by ponatinib and makes ponatinib a much more potent inhibitor of hepatocellular carcinoma cell proliferation. These findings demonstrate that ponatinib exerts both positive and negative effects on hepatocellular cell proliferation, and eliminating its growth-stimulating effects by drug combination or potentially by chemical medication can significantly improve its efficacy as an anti-cancer drug.

Neural stem cells promote glioblastoma formation in nude mice

PURPOSE

Neural stem cells (NSCs) have been characterized with the ability of self-renewal and neurogenesis, which has inspired lots of studies to clarify the functions of NSCs in neural injury, ischemic stroke, brain inflammation and neurodegenerative diseases. We focused on the relationship of NSCs with glioblastoma, since we have discovered that recurrent glioblastomas were inclined to be derived from subventricular zone (SVZ), where NSCs reside. We want to clarify whether NSCs are involved in glioblastoma relapse.

METHODS

Immunocytochemistry was used to confirm the stemness of NSCs. The Cell Counting Kit-8 was used to measure the proliferation of cells. Migration abilities were examined by wound healing and transwell assays, and tumor formation abilities were confirmed in nude mice.

RESULTS

We found in experiments that NSCs promoted proliferation of a glioblastoma cell line-Ln229, the migration ability of Ln229 cells was motivated by co-cultured with NSCs. Tumor formation of Ln229 cells was also accelerated in nude mice when co-transplanted with NSCs. In immunohistochemistry, we found that the Sox2- and Ki67-positive cells were much higher in co-transplanted groups than that of control groups.

CONCLUSIONS

These results imply the potential role that NSCs play in speeding up tumor formation in the process of glioblastoma relapse, providing the basis for dealing with newly diagnosed glioblastoma patients, which may help postpone the recurrence of glioblastoma as far as possible through preprocessing the tumor-adjacent SVZ tissue.

MRPL35 Is Up-Regulated in Colorectal Cancer and Regulates Colorectal Cancer Cell Growth and Apoptosis

Mitochondrial ribosome proteins (MRPs), which are encoded by the nuclear genomic DNA, are important for mitochondrial-encoded protein synthesis and mitochondrial function. Emerging evidence suggests that several MRPs also exhibit important extra-mitochondrial functions, such as involvement in apoptosis, protein biosynthesis, and signal transduction. In this study, we demonstrate a significant role of MRP L35 (MRPL35) in colorectal cancer (CRC). The expression of MRPL35 was higher in CRC tissues than in matched cancer-adjacent tissues and higher in CRC cells than in normal mucosal epithelial cells. Higher MRPL35 expression in CRC tissue correlated with shorter overall survival for CRC patients. In vitro, down-regulation of MRPL35 led to increased production of reactive oxygen species (ROS) together with DNA damage, loss of cell proliferation, G₂/M arrest, a decrease in mitochondrial membrane potential, apoptosis, and autophagy induction. MRPL35 knockdown inhibited tumor proliferation in a CRC xenograft nude mouse model. Furthermore, overexpression of MRPL35 or treatment of cells with the ROS scavenger, N-acetyl cysteine, abrogated ROS production, cell cycle arrest, and apoptosis in vitro. These findings suggest that MRPL35 plays an essential role in the development of CRC and may be a potential therapeutic target for CRC.

Abstract P6-02-14: Not presented

This abstract was not presented at the conference.

Citation Format: Xing W, Li Q, Sun G, Cao R, Chen B, Jiang C, Ma L, Wang K. Not presented [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-02-14.

Abstract P2-01-25: Not presented

This abstract was not presented at the conference.

Citation Format: Xing W, Li Q, Cao R, Sun G, Jiang C. Not presented [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P2-01-25.

Drug Sensitivity Screening and Targeted Pathway Analysis Reveal a Multi-Driver Proliferative Mechanism and Suggest a Strategy of Combination Targeted Therapy for Colorectal Cancer Cells

Treatment of colorectal cancer mostly relies on traditional therapeutic approaches, such as surgery and chemotherapy. Limited options of targeted therapy for colorectal cancer narrowly focus on blocking cancer-generic targets VEGFR and EGFR. Identifying the oncogenic drivers, understanding their contribution to proliferation, and finding inhibitors to block such drivers are the keys to developing targeted therapy for colorectal cancer. In this study, ten colorectal cancer cell lines were screened against a panel of protein kinase inhibitors blocking key oncogenic signaling pathways. The results show that four of the 10 cell lines did not respond to any kinase inhibitors significantly, the other six were mildly inhibited by AZD-6244, BMS-754807, and/or dasatinib. Mechanistic analyses demonstrate that these inhibitors independently block the MAP kinase pathway, IR/IGF-1R/AKT pathway, and Src kinases, suggesting a multi-driver nature of proliferative signaling in these cells. Most of these cell lines were potently and synergistically inhibited by pair-wise combinations of these drugs. Furthermore, seven of the 10 cell lines were inhibited by the triple combination of AZD-6244/BMS-754807/dasatinib with IC₅₀’s between 10 and 84 nM. These results suggest that combination targeted therapy may be an effective strategy against colorectal cancer.

Evidence for activated Lck protein tyrosine kinase as the driver of proliferation in acute myeloid leukemia cell, CTV-1

Acute myeloid leukemia (AML) is a heterogeneous group of fast growing cancers of myeloid progenitor cells, for which effective treatments are still lacking. Identification of signaling inhibitors that block their proliferation could reveal the proliferative mechanism of a given leukemia cell, and provide small molecule drugs for targeted therapy for AML. In this study, kinase inhibitors that block the majority of cancer signaling pathways are evaluated for their inhibition of two AML cell lines of the M5 subtypes, CTV-1 and THP-1. While THP-1 cells do not respond to any of these inhibitors, CTV-1 cells are potently inhibited by dasatinib, bosutinib, crizotinib, A-770041, and WH-4-23, all potent inhibitors for Lck, a Src family kinase. CTV-1 cells contain a kinase activity that phosphorylates an Lck-specific peptide substrate in an Lck inhibitor-sensitive manner. Furthermore, the Lck gene is over-expressed in CTV-1, and it contains four mutations, two of which are located in regions critical for Lck negative regulation, and are confirmed to activate Lck. Collectively, these results provide strong evidence that mutated and overexpressed Lck is driving CTV-1 proliferation. While Lck activation and overexpression is rare in AML, this study provides a potential therapeutic strategy for treating patients with a similar oncogenic mechanism.

The clinical significance of perineural invasion in patients with de novo metastatic prostate cancer

BACKGROUND

The clinical value of perineural invasion (PNI) in patients with localized prostate cancer (PCa) is widely explored. However, its role in metastatic PCa (mPCa) remains unknown.

OBJECTIVES

We aim to investigate the clinical significance of PNI in patients with mPCa.

MATERIALS AND METHODS

Data of 515 mPCa patients between 2012 and 2018 were retrospectively studied. PNI and its intensity were identified by prostate biopsy. The prognostic value of PNI was evaluated by Kaplan-Meier curves and Cox proportional-hazards model.

RESULTS

Perineural invasion was detected in 170/515 (33.0%) cases. Among them 73/170 (42.9%) and 97/170 (57.1%) harbored unifocal PNI (uni-PNI) and multifocal PNI (multi-PNI), respectively. Compared to patients without PNI, those with PNI had statistically shorter castration-resistant PCa-free survival (CFS) and numerically shorter overall survival (OS) (mCFS: 15.4- vs. 18.5-Mo, p = 0.015; mOS: 63.8- vs. 71.4-Mo, p = 0.108). Patients harboring multi-PNI were associated with poorer clinical outcomes than those with uni-PNI (mCFS: 12.4- vs. 18.0-Mo, p = 0.040; mOS: 39.7-Mo vs. NR, p = 0.018) or those without PNI (mCFS: 12.4- vs. 18.5-Mo, p = 0.002; mOS: 39.7- vs. 71.4-Mo, p = 0.002). Totally, neither uni-PNI nor multi-PNI was an independent risk factor impacting survival outcomes in multivariate analyses. While remarkably, for patients with favorable/intermediate-risk mPCa, multi-PNI was an independent adverse prognosticator for both CFS and OS (CFS: HR: 1.705, 95% CI: 1.029-2.825, p = 0.038; OS: HR: 3.294, 95% CI: 1.464-7.413, p = 0.004).

DISCUSSION AND CONCLUSION

This study filled the blank of the clinical significance of PNI in mPCa. We found that multi-PNI could distinguish men with relatively poor prognosis from patients initially regarded as with favorable survival outcomes by other prognosticators, and thus, avoid disease underestimation in this group of patients. Our finding would help physicians have a deeper understanding of the heterogeneity of mPCa and make better individualized therapeutic strategy.

Structural versatility that serves the function of the HRD motif in the catalytic loop of protein tyrosine kinase, Src

Site-directed mutagenesis is a traditional approach for structure-function analysis of protein tyrosine kinases, and it requires the generation, expression, purification, and analysis of each mutant enzyme. In this study, we report a versatile high throughput bacterial screening system that can identify functional kinase mutants by immunological detection of tyrosine phosphorylation. Two key features of this screening system are noteworthy. First, instead of blotting bacterial colonies directly from Agar plates to nitrocellulose membrane, the colonies were cultured in 96-well plates, and then spotted in duplicate onto the membrane with appropriate controls. This made the screening much more reliable compared with direct colony blotting transfer. A second feature is the parallel use of a protein tyrosine phosphatase (PTP)-expressing host and a non-PTP-expressing host. Because high activity Src mutants are toxic to the host, the PTP system allowed the identification of Src mutants with high activity, while the non-PTP system identified Src mutants with low activity. This approach was applied to Src mutant libraries randomized in the highly conserved HRD motif in the catalytic loop, and revealed that structurally diverse residues can replace the His and Arg residues, while the Asp residue is irreplaceable for catalytic activity.

RasGRF2 promotes migration and invasion of colorectal cancer cells by modulating expression of MMP9 through Src/Akt/NF-κB pathway

Ras-specific guanine nucleotide-releasing factor 2 (RasGRF2) is a member of the guanine nucleotide exchange factors family which is expressed in a variety of tissues and cancer. However, the role of RasGRF2 in cancer is less reported, especially in colorectal cancer(CRC). Hence, the present study aimed to investigated the function of RasGRF2 and ways in which it affects tumor progression in CRC samples and cell lines. We first measured RasGRF2 mRNA level in 26 paired tumor and nontumor colon tissues after colon cancer surgical resection, and determined RasGRF2 protein level in 97 paired paraffin-embedded colon cancer tissues, and found that levels of RasGRF2 mRNA and protein were increased in colorectal tumor tissues, compared with adjacent non-tumor tissues. We then examined the effects of RasGRF2 knockdown on proliferation, migration and invasion were analyzed in CRC cells (SW480, HCT116 and LS174T). HCT116 cells with RasGRF2 knockdown were injected into the tail vein in nude mice to yield metastatic model, and tumor metastasis was measured as well. We found that knockdown of RasGRF2 in CRC cells reduced their migration and invasion in vitro and metastasis in mice. Furthermore, we explored the underlying molecular mechanism for RasGRF2-mediated CRC migration and invasion. The results showed that knockdown of RasGRF2 in CRC cells impairing the expression of MMP9 and inhibiting the activation of Src/Akt and NF-κB signaling. We conclude that RasGRF2 plays a role in controlling migration and invasion of CRC and modulates the expression of MMP9 through Src/PI 3-kinase and the NF-κB pathways.

Comparative analysis of the blood transcriptomes between wolves and dogs

Dogs were domesticated by human and originated from wolves. Their evolutionary relationships have attracted much scientific interest due to their genetic affinity but different habitats. To identify the differences between dogs and wolves associated with domestication, we analysed the blood transcriptomes of wolves and dogs by RNA-Seq. We obtained a total of 30.87 Gb of raw reads from two dogs and three wolves using RNA-Seq technology. Comparisons of the wolf and dog transcriptomes revealed 524 genes differentially expressed genes between them. We found that some genes related to immune function (DCK, ICAM4, GAPDH and BSG) and aerobic capacity (HBA1, HBA2 and HBB) were more highly expressed in the wolf. Six differentially expressed genes related to the innate immune response (CCL23, TRIM10, DUSP10, RAB27A, CLEC5A and GCH1) were found in the wolf by a Gene Ontology enrichment analysis. Immune system development was also enriched only in the wolf group. The ALAS2, HMBS and FECH genes, shown to be enriched by the Kyoto Encyclopedia of Genes and Genomes analysis, were associated with the higher aerobic capacity and hypoxia endurance of the wolf. The results suggest that the wolf might have greater resistance to pathogens, hypoxia endurance and aerobic capacity than dogs do.

Clinical Complications of Combined Phacoemulsification and Vitrectomy for Eyes with Coexisting Cataract and Vitreoretinal Diseases

Purpose

To discuss the intraoperative and postoperative complications of combining phacoemulsification and foldable intraocular lens (IOL) implantation with pars plana vitrectomy in eyes with significant cataract and coexisting vitreoretinal diseases.

Methods

This retrospective study consisted of 186 eyes of 149 patients with various vitreoretinal abnormalities and visually significant cataracts. Vitreoretinal surgery was combined with clear corneal phacoemulsification and foldable IOL implantation. Main outcome measures were the intraoperative and postoperative complications at from 6 to 56 months.

Results

The most common intraoperative complication was iatrogenic retinal hole (5.3%), transient corneal edema (3.2%), and posterior capsule break (2.1%). The most common postoperative complication was posterior capsule opacification (21.5%) and elevated intraocular pressure (9.7%), macular edema (8.1%), fibrinous reaction (6.9%), vitreous hemorrhage (3.7%), posterior synechiae (3.7%), and recurrent retinal detachment (3.2%). Postoperatively, in 162 eyes (87.1%), visual acuity improved by 3 lines or more on the Snellen chart. In 14 eyes (7.5%), vision remained within 3 lines of preoperative levels and in 10 eyes (5.3%), vision had decreased at the last follow-up.

Conclusions

Postoperative complications did not increase significantly in the combined phacoemulsification and vitreoretinal surgery. Combined vitreoretinal surgery and phacoemulsification with foldable IOL implantation is safe and effective in treating vitreoretinal abnormalities coexisting with cataract. Based on extensive experience with the combined procedure, the authors suggest that combined surgery is recommended in select patients having simultaneous vitreoretinal pathologic changes and cataract.

Taurine attenuates acrylamide-induced apoptosis via a PI3K/AKT-dependent manner

As a potent neurotoxic agent, acrylamide (ACR) is formed in food processing at higher temperature. Taurine (TAU), a nonessential amino acid, is used to cure neurodegenerative disorders, followed by activation of the phosphatidylinositol 3-kinase/protein kinase B (PI3K/AKT) signaling pathway. In this article, we certified that antiapoptotic efficacy of TAU in vivo and vitro. ACR-treated rats received TAU by drinking water 2 weeks after ACR intoxication. The results showed that in treated rats, TAU alleviated ACR-induced neuronal apoptosis, which was associated with the activation of PI3K/AKT signaling pathway. TAU attenuated apoptosis caused by ACR through observing terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL)-positive cells, measure of protein expression of Bcl-2, Bax, and caspase 3 activity. TAU-induced antiapoptotic effect is PI3K/AKT-dependent, which was proved in ACR-intoxicated ventral spinal cord 4.1 cells in the presence of AKT inhibitor, MK-2206. Therefore, our results demonstrated that TAU-attenuated ACR-induced apoptosis in vivo through a PI3K/AKT-dependent manner provided new sights in the molecular mechanism of TAU protection against ACR-induced neurotoxicity.

RNA-sequencing study of peripheral blood mononuclear cells in sporadic Ménière's disease patients: possible contribution of immunologic dysfunction to the development of this disorder

To date, the pathogenesis of Ménière's disease (MD) remains unclear. This study aims to investigate the possible relationship between potential immune system-related genes and sporadic MD. The whole RNA-sequencing (RNA-seq) technology was used to analyse the transcriptome of peripheral blood mononuclear cells of three MD patients and three control individuals. Of 366 differentially expressed genes (DEGs), 154 genes were up-regulated and 212 genes were down-regulated (|log₂ fold change| > 1 and P < 0·05). Gene ontology (GO) enrichment analysis illustrated that immune relevant factors played a key role in the pathogenesis of MD. Of 366 DEGs, we focused upon analysing the possible immune-related genes, among which the significantly up-regulated genes [glutathione S-transferase mu 1 (GSTM1), transmembrane protein 176 (TMEM176)B, TMEM176A] and down-regulated genes [solute carrier family 4 member (SLC4A)10 and SLC4A1] especially drew our attention. The mRNA expression levels of GSTM1, TMEM176B, TMEM176A, SLC4A1 and SLC4A10 were analysed by quantitative reverse transcription-polymerase chain reaction (qRT-PCR). The serum concentration of GSTM1, TMEM176B and SLC4A10 proteins were measured by enzyme-linked immunosorbent assay (ELISA). Considering the results of qRT-PCR and ELISA, it was noteworthy that GSTM1 exhibited the highest fold change between two groups, which was consistent with the deep sequencing results by RNA-seq. In conclusion, our study first offers a new perspective in MD development on the basis of RNA expression patterns, suggesting that immune factors might be involved in the MD pathogenesis. Remarkably, GSTM1 might be a possible candidate gene for the diagnostic biomarker of MD and provides the basis for further biological and functional investigations.