Prediction of the VeriStrat test in first-line therapy of pemetrexed-based regimens for advanced lung adenocarcinoma patients.

BACKGROUND: Although advanced non-squamous non-small cell lung cancer (NSCLC) patients have significantly better survival outcomes after pemetrexed based treatment, a subset of patients still show intrinsic resistance and progress rapidly. Therefore we aimed to use a blood-based protein signature (VeriStrat, VS) to analyze whether VS could identify the subset of patients who had poor efficacy on pemetrexed therapy. METHODS: This study retrospectively analysed 72 advanced lung adenocarcinoma patients who received first-line pemetrexed/platinum or combined with bevacizumab treatment. RESULTS: Plasma samples from these patients were analysed using VS and classified into the Good (VS-G) or Poor (VS-P) group. The relationship between efficacy and VS status was further investigated. Of the 72 patients included in this study, 35 (48.6%) were treated with pemetrexed plus platinum and 37 (51.4%) were treated with pemetrexed/platinum combined with bevacizumab. Among all patients, 60 (83.3%) and 12 (16.7%) patients were classified as VS-G and VS-P, respectively. VS-G patients had significantly better median progression-free survival (PFS) (Unreached vs. 4.2 months; P < 0.001) than VS-P patients. In addition, the partial response (PR) rate was higher in the VS-G group than that in the VS-P group (46.7% vs. 25.0%, P = 0.212). Subgroup analysis showed that PFS was also significantly longer in the VS-G group than that in the VS-P group regardless of whether patients received chemotherapy alone or chemotherapy plus bevacizumab. CONCLUSIONS: Our study indicated that VS might be considered as a novel and valid method to predict the efficacy of pemetrexed-based therapy and identify a subset of advanced lung adenocarcinoma patients who had intrinsic resistance to pemetrexed based regimens. However, larger sample studies are still needed to further confirm this result.

Nomogram model for predicting cause-specific mortality in patients with stage I small-cell lung cancer: a competing risk analysis.

BACKGROUND: The five-year cumulative incidence rate in patients diagnosed with stage I small-cell lung cancer (SCLC) who were instructed to undergo surgery was from 40 to 60%.The death competition influence the accuracy of the classical survival analyses. The aim of the study is to investigate the mortality of stage I small-cell lung cancer (SCLC) patients in the presence of competing risks according to a proportional hazards model, and to establish a competing risk nomogram to predict probabilities of both cause-specific death and death resulting from other causes. METHODS: The study subjects were patients diagnosed with stage I SCLC according to ICD-O-3. First, the cumulative incidence functions (CIFs) of cause-specific death, as well as of death resulting from other causes, were calculated. Then, a proportional hazards model for the sub-distribution of competing risks and a monogram were constructed to evaluate the probability of mortality in stage I SCLC patients. RESULTS: 1811 patients were included in this study. The five-year probabilities of death due to specific causes and other causes were 61.5 and 13.6%, respectively. Tumor size, extent of tumor, surgery, and radiotherapy were identified as the predictors of death resulting from specific causes in stage I SCLC. The results showed that surgery could effectively reduce the cancer-specific death, and the one-year cumulative incidence dropped from 34.5 to 11.2%. Like surgery, chemotherapy and radiotherapy improved the one-year survival rate. CONCLUSIONS: We constructed a predictive model for stage I SCLC using the data from the SEER database. The proportional sub-distribution models of competing risks revealed the predictors of death resulting from both specific causes and other causes. The competing risk nomogram that we built to predict the prognosis showed good reliability and could provide beneficial and individualized predictive information for stage I SCLC patients.

Downregulation of RUNX1/CBFß by MLL fusion proteins enhances hematopoietic stem cell self-renewal.

RUNX1/CBFß (core binding factor [CBF]) is a heterodimeric transcription factor complex that is frequently involved in chromosomal translocations, point mutations, or deletions in acute leukemia. The mixed lineage leukemia (MLL) gene is also frequently involved in chromosomal translocations or partial tandem duplication in acute leukemia. The MLL protein interacts with RUNX1 and prevents RUNX1 from ubiquitin-mediated degradation. RUNX1/CBFß recruits MLL to regulate downstream target genes. However, the functional consequence of MLL fusions on RUNX1/CBFß activity has not been fully understood. In this report, we show that MLL fusion proteins and the N-terminal MLL portion of MLL fusions downregulate RUNX1 and CBFß protein expression via the MLL CXXC domain and flanking regions. We confirmed this finding in Mll-Af9 knock-in mice and human M4/M5 acute myeloid leukemia (AML) cell lines, with or without MLL translocations, showing that MLL translocations cause a hypomorph phenotype of RUNX1/CBFß. Overexpression of RUNX1 inhibits the development of AML in Mll-Af9 knock-in mice; conversely, further reducing Runx1/Cbfß levels accelerates MLL-AF9-mediated AML in bone marrow transplantation assays. These data reveal a newly defined negative regulation of RUNX1/CBFß by MLL fusion proteins and suggest that targeting RUNX1/CBFß levels may be a potential therapy for MLLs.

Stress hematopoiesis reveals abnormal control of self-renewal, lineage bias, and myeloid differentiation in Mll partial tandem duplication (Mll-PTD) hematopoietic stem/progenitor cells.

One mechanism for disrupting the MLL gene in myelodysplastic syndrome (MDS) and acute myeloid leukemia (AML) is through partial tandem duplication (MLL-PTD); however, the mechanism by which MLL-PTD contributes to MDS and AML development and maintenance is currently unknown. Herein, we investigated hematopoietic stem/progenitor cell (HSPC) phenotypes of Mll-PTD knock-in mice. Although HSPCs (Lin(-)Sca1(+)Kit(+) (LSK)/SLAM(+) and LSK) in Mll(PTD/WT) mice are reduced in absolute number in steady state because of increased apoptosis, they have a proliferative advantage in colony replating assays, CFU-spleen assays, and competitive transplantation assays over wild-type HSPCs. The Mll(PTD/WT)-derived phenotypic short-term (ST)-HSCs/multipotent progenitors and granulocyte/macrophage progenitors have self-renewal capability, rescuing hematopoiesis by giving rise to long-term repopulating cells in recipient mice with an unexpected myeloid differentiation blockade and lymphoid-lineage bias. However, Mll(PTD/WT) HSPCs never develop leukemia in primary or recipient mice, suggesting that additional genetic and/or epigenetic defects are necessary for full leukemogenic transformation. Thus, the Mll-PTD aberrantly alters HSPCs, enhances self-renewal, causes lineage bias, and blocks myeloid differentiation. These findings provide a framework by which we can ascertain the underlying pathogenic role of MLL-PTD in the clonal evolution of human leukemia, which should facilitate improved therapies and patient outcomes.

The ability of MLL to bind RUNX1 and methylate H3K4 at PU.1 regulatory regions is impaired by MDS/AML-associated RUNX1/AML1 mutations.

The mixed-lineage leukemia (MLL) H3K4 methyltransferase protein, and the heterodimeric RUNX1/CBFß transcription factor complex, are critical for definitive and adult hematopoiesis, and both are frequently targeted in human acute leukemia. We identified a physical and functional interaction between RUNX1 (AML1) and MLL and show that both are required to maintain the histone lysine 4 trimethyl mark (H3K4me3) at 2 critical regulatory regions of the AML1 target gene PU.1. Similar to CBFß, we show that MLL binds to AML1 abrogating its proteasome-dependent degradation. Furthermore, a subset of previously uncharacterized frame-shift and missense mutations at the N terminus of AML1, found in MDS and AML patients, impairs its interaction with MLL, resulting in loss of the H3K4me3 mark within PU.1 regulatory regions, and decreased PU.1 expression. The interaction between MLL and AML1 provides a mechanism for the sequence-specific binding of MLL to DNA, and identifies RUNX1 target genes as potential effectors of MLL function.

Intracellular delivery of artificial transcription factors fused to the protein transduction domain of HIV-1 Tat.

Protein transduction domains (PTDs), such as the TAT peptide derived from HIV Tat protein, may transduce macromolecules into cells. In the present study, the TAT peptide-fused artificial transcription factors (ATFs) were generated by fusion of the N-terminal TAT peptide with SV40 promoter-targeted three-fingered C2H2 zinc finger proteins and the KRAB transcriptional repression domain. The fusion proteins were then expressed in an E .coli system and purified by Ni-NTA affinity chromatography. The purified fusion proteins were tested on mammalian cell lines CHO DG44 and L929. TAT-ATF-S, which contains the zinc fingers that bind to the SV40 promoter with high specificity, exhibited the desired transcriptional repression activity to the reported genes, indicating the successful cellular delivery and desired conformation of TAT-ATF-S. Our study has provided a new strategy for intracellular ATF delivery.

Whole-Transcriptome Analysis Highlights Adenylyl Cyclase Toxins-Derived Modulation of NF-κB and ERK1/2 Pathways in Macrophages.

Edema toxin (ET), one of the main toxic factors of Bacillus anthracis (B. anthracis), is a kind of potent adenylate cyclase (AC). B. anthracis has adapted to resist macrophage microbicidal mechanisms in part by secreting ET. To date, there is limited information on the pathogenic mechanisms used by ET to manipulate macrophage function, especially at the transcriptome level. We used RNA sequencing to study transcriptional changes in RAW264.7 cells treated with ET. We aimed to identify molecular events associated with the establishment of infection and followed changes in cellular proteins. Our results indicate that ET inhibited TNF-α expression in the RAW264.7 mouse macrophage cell line by activating the cAMP/PKA pathway. ET challenge of macrophages induced a differential expression of genes that participate in multiple macrophage effector functions such as cytokine production, cell adhesion, and the inflammatory response. Furthermore, ET influenced the expression of components of the ERK1/2, as well as the NF-αB signaling pathways. We also showed that ET treatments inhibit the phosphorylation of the ERK1/2 protein. ET also attenuated NF-αB subunit p65 phosphorylation and transcriptional activity of NF-αB via the cAMP/PKA pathway in macrophages. Since the observed modulatory effects were characteristic only of the bacterial exotoxin ET, we propose this may be a mechanism used by B. anthracis to manipulate macrophages and establish systemic infection.

Latexin regulates sex dimorphism in hematopoiesis via gender-specific differential expression of microRNA 98-3p and thrombospondin 1.

Hematopoietic stem cells (HSCs) have the ability to self-renew and differentiate to all blood cell types. HSCs and their differentiated progeny show sex/gender differences. The fundamental mechanisms remain largely unexplored. We previously reported that latexin (Lxn) deletion increased HSC survival and repopulation capacity in female mice. Here, we find no differences in HSC function and hematopoiesis in Lxn knockout (Lxn-/-) male mice under physiologic and myelosuppressive conditions. We further find that Thbs1, a downstream target gene of Lxn in female HSCs, is repressed in male HSCs. Male-specific high expression of microRNA 98-3p (miR98-3p) contributes to Thbs1 suppression in male HSCs, thus abrogating the functional effect of Lxn in male HSCs and hematopoiesis. These findings uncover a regulatory mechanism involving a sex-chromosome-related microRNA and its differential control of Lxn-Thbs1 signaling in hematopoiesis and shed light on the process underlying sex dimorphism in both normal and malignant hematopoiesis.

Real-time arrhythmia detection using convolutional neural networks.

Cardiovascular diseases, such as heart attack and congestive heart failure, are the leading cause of death both in the United States and worldwide. The current medical practice for diagnosing cardiovascular diseases is not suitable for long-term, out-of-hospital use. A key to long-term monitoring is the ability to detect abnormal cardiac rhythms, i.e., arrhythmia, in real-time. Most existing studies only focus on the accuracy of arrhythmia classification, instead of runtime performance of the workflow. In this paper, we present our work on supporting real-time arrhythmic detection using convolutional neural networks, which take images of electrocardiogram (ECG) segments as input, and classify the arrhythmia conditions. To support real-time processing, we have carried out extensive experiments and evaluated the computational cost of each step of the classification workflow. Our results show that it is feasible to achieve real-time arrhythmic detection using convolutional neural networks. To further demonstrate the generalizability of this approach, we used the trained model with processed data collected by a customized wearable sensor from a lab setting, and the results shown that our approach is highly accurate and efficient. This research provides the potentials to enable in-home real-time heart monitoring based on 2D image data, which opens up opportunities for integrating both machine learning and traditional diagnostic approaches.

Establishment of tetracycline-inducible, survivin-expressing CHO cell lines by an optimized screening method.

An optimized method based on tetracycline-inducible gene expression system T-REx was developed to screen and evaluate Tet repressor (TetR)-expressing cell lines using enhanced green fluorescence protein (EGFP) as reporter gene. To verify the effectiveness of the method, two TetR-expressing Chinese hamster ovary (CHO) cell lines, CHO-TR B2 (stringent) and B5 (less stringent), in which the EGFP genes were variantly controlled by tetracycline, were used to construct cell lines expressing the anti-apoptosis gene survivin upon induction with tetracycline. The resulting stable clones were analyzed for survivin expression. The analysis showed that all four B5-derived clones exhibited leaky survivin expression in the absence of tetracycline, while the B2-derived clones did not. DNA laddering and annexin V/PI staining assays further indicated that although tetracycline-inducible expression of survivin conferred resistance to NH4Cl- and staurosporine-induced apoptosis in both the B2- and the B5-derived stable cell lines, the B2-derived cell lines showed more stringent regulation in the absence of tetracycline. This represents successful utilization of the present screening method.

Sex differences in normal and malignant hematopoiesis.

Hematopoiesis is a continuous and well-regulated process requiring both the capacity for self-renewal and the potential for differentiation of hematopoietic stem cells. Multiple studies indicate that sex hormones exert significant effects on not only hematopoietic stem and progenitor cells, but also the development of hematopoietic lineages, resulting in sexual dimorphisms in normal hematopoiesis. Hematologic malignancies comprise a wide variety of cancers affecting the blood, bone marrow, and lymphatic system, such as leukemia, lymphoma, myeloma, myelodysplastic syndrome, and myeloproliferative diseases. Overall, males are at greater risk and have worse prognosis for most of these malignancies compared with females. A better understanding of the differences between male and female could be of substantial value in research as well as clinical management.

Recent Advances in Lipid Nanoparticles for Delivery of mRNA.

Messenger RNA (mRNA), which is composed of ribonucleotides that carry genetic information and direct protein synthesis, is transcribed from a strand of DNA as a template. On this basis, mRNA technology can take advantage of the body's own translation system to express proteins with multiple functions for the treatment of various diseases. Due to the advancement of mRNA synthesis and purification, modification and sequence optimization technologies, and the emerging lipid nanomaterials and other delivery systems, mRNA therapeutic regimens are becoming clinically feasible and exhibit significant reliability in mRNA stability, translation efficiency, and controlled immunogenicity. Lipid nanoparticles (LNPs), currently the leading non-viral delivery vehicles, have made many exciting advances in clinical translation as part of the COVID-19 vaccines and therefore have the potential to accelerate the clinical translation of gene drugs. Additionally, due to their small size, biocompatibility, and biodegradability, LNPs can effectively deliver nucleic acids into cells, which is particularly important for the current mRNA regimens. Therefore, the cutting-edge LNP@mRNA regimens hold great promise for cancer vaccines, infectious disease prevention, protein replacement therapy, gene editing, and rare disease treatment. To shed more lights on LNP@mRNA, this paper mainly discusses the rational of choosing LNPs as the non-viral vectors to deliver mRNA, the general rules for mRNA optimization and LNP preparation, and the various parameters affecting the delivery efficiency of LNP@mRNA, and finally summarizes the current research status as well as the current challenges. The latest research progress of LNPs in the treatment of other diseases such as oncological, cardiovascular, and infectious diseases is also given. Finally, the future applications and perspectives for LNP@mRNA are generally introduced.

Tylvalosin demonstrates anti-parasitic activity and protects mice from acute toxoplasmosis.

AIMS: Toxoplasmosis, caused by Toxoplasma gondii (Tg), is one of the most prevalent zoonotic diseases worldwide. Currently, safe and efficient therapeutic options for this disease are still being developed, and are urgently needed. Tylvalosin (Tyl), a broad-spectrum third-generation macrolide, exhibits anti-bacterial, anti-viral, and anti-inflammatory properties. The present study aims to explore the anti-parasitic and immunomodulation activities of Tyl against Tg, and the underlying mechanism. MAIN METHODS: Adhesion, invasion, replication, proliferation, plaque, reversibility, immunofluorescence assays and transmission electron microscopy were utilized to determine the anti-Toxoplasma effect of Tyl. With acute toxoplasmosis model and rabies virus-induced brain inflammation model, the anti-toxoplasmosis and immunomodulation activities of Tyl were assessed by colorimetric assay, histopathological and Oil red O staining, and real-time quantitative PCR. The involved molecular mechanisms were investigated by western blotting and immunohistochemical staining. KEY FINDINGS: Tyl (5 and 10 µg/ml) can inhibit Tg propagation, and damage its ultrastructure irreversibly. The combination of Tyl and Pyrimethamine (Pyr) exhibits a better synergistic effect. Tyl (50 and 100 mg/kg) treatment intraperitoneally can delay mice death and improve survival rate, accompanying the reduced histopathological score and parasite load in the indicated tissues, espically for ileum, liver, spleen, lung and brain. Furthermore, Tg can modulate host phospho-p38 MAPK (pp38), subtilisin/kexin-isozyme-1 (SKI-1)-sterol regulatory element binding protein-1 (SREBP-1) (SKI-1-SREBP-1) pathway and peroxisome proliferators-activated receptor δ (PPARδ), while Tyl is able to reverse these signal pathways close to normal levels. SIGNIFICANCE: Our findings indicate that Tyl exhibits anti-Toxoplasma activity and protects mice from acute toxoplasmosis.

Overexpression of survivin and cyclin D1 in CHO cells confers apoptosis resistance and enhances growth in serum-free suspension culture.

To optimize Chinese hamster ovary (CHO) cell culture to recombinant protein therapeutic production, we stably overexpressed survivin and cyclin D1 in three CHO DG44-derived cell lines. The modifications conferred increases of 56-94% in S-phase fractions and decreases of 33-43% in early-stage apoptosis fractions. Clone 6.3, which expressed the highest levels of survivin and cyclin D1, reached significantly greater cell densities in suspension (2.7 × 10(6) cells/ml) following serum deprivation. Nude mice inoculated with the modified cells showed no tumorigenesis suggesting that the CHO DG44-derived cell lines are viable candidates for biopharmaceutical production.

Interactions of Hematopoietic Stem Cells with Bone Marrow Niche.

Hematopoietic stem cells (HSCs) are ultimately responsible for the lifelong renewal of all blood cell lineages. In the bone marrow (BM), HSCs reside in specialized microenvironments referred to as the "niche." HSC niche consists of complex components including heterogeneous cell populations, growth factors, and extracellular matrix molecules. The crosstalk between HSCs and their niche is essential to regulate the survival, self-renewal, migration, quiescence, and differentiation of HSCs. The application of mice models with endogenous ablation of specific cell types, advanced imaging technologies, high-throughput single-cell RNA sequencing, and single-cell mass cytometry methods have provided deep insights into communications between HSCs and niche cells. In this chapter, we have focused on three important cell types in the BM niche: mesenchymal stem cells (MSCs), osteoblasts (OBs), and endothelial cells (ECs). In order to address the interaction between HSCs and these three cell populations in BM niche, we have described methodology for (1) collecting total BM from femur and tibia of C57BL/6 mice; (2) analyzing or sorting of MSCs, OBs, and ECs based on the selection of surface markers CD45, Ter119, CD31, Sca1, and CD51 with flow cytometry; and (3) co-culturing the sorted cells with purified HSCs for further functional assays of HSCs.

Lipid metabolism is a novel and practical source of potential targets for antiviral discovery against porcine parvovirus.

How parvovirus manipulates host lipid metabolism to facilitate its propagation, pathogenicity and consequences for disease, is poorly characterized. Here, we addressed this question using porcine parvovirus (PPV) to understand the complex interactions of parvovirus with lipid metabolism networks contributing to the identification of novel and practical antiviral candidates. PPV significantly alters host lipid composition, characteristic of subclasses of phospholipids and sphingolipids, and induces lipid droplets (LDs) formation via regulating calcium-independent PLA2ß (iPLA2ß), phospholipase Cγ2 (PLCγ2), diacylglycerol kinase α (DKGα), phosphoinositide 3-kinase (PI3K), lysophosphatidic acid acyltransferase θ (LPAATθ), and sphingosine kinases (SphK1 and SphK2). PPV utilizes and exploits these enzymes as well as their metabolites and host factors including MAPKs (p38 and ERK1/2), protein kinase C (PKC) and Ca2+ to induce S phase arrest, apoptosis and incomplete autophagy, all benefit to PPV propagation. PPV also suppresses prostaglandin E2 (PGE2) synthesis via downregulating cyclooxygenase-1 (COX-1), indicating PPV hijacks COX-1-PGE2 axis to evade immune surveillance. Our data support a model where PPV to establishes an optimal environment for its propagation and pathogenicity via co-opting host lipid metabolism, being positioned as a source of potential targets.

Plasma cytokines interleukin-18 and C-X-C motif chemokine ligand 10 are indicative of the anti-programmed cell death protein-1 treatment response in lung cancer patients.

BACKGROUND: Although programmed cell death protein-1 (PD-1)/programmed death ligand-1 (PD-L1) checkpoint inhibitors have shown prominent efficacy for treatment of advanced lung cancer, the outcomes of metastatic lung cancer remain poor throughout the world. Although progression-free survival (PFS) and overall survival (OS) have improved in the first- and second-line therapy settings for advanced lung cancer, the response rates to PD-1/PD-L1 inhibition range from 20% to 40%. Furthermore, patients may be at risk for immune-related adverse events (irAEs); hence, appropriate patient selection is crucial. This study aimed to identify a panel of plasma cytokines representing prognostic and predictive biomarkers of the response to anti-PD-1/PD-L1 treatment. METHODS: We prospectively studied 32 lung cancer patients who received anti-PD-1/PD-L1 antibody immunotherapy. Plasma cytokines in peripheral blood samples were evaluated and analyzed using flow cytometry at the time of diagnosis and at 2 months after the initiation of PD-1/PD-L1 inhibition. RESULTS: The baseline plasma concentrations of interleukin-18 (IL-18) and C-X-C motif chemokine ligand 10 (CXCL10) were correlated with the degree of tumor response. Moreover, the magnitude of plasma IL-18 and CXCL10 level fluctuations were correlated significantly with the objective tumor response to anti-PD-1/PD-L1 immunotherapy, and patients with high CXCL10 expression had significantly shorter PFS than those with low CXCL10 expression. A strong positive correlation between the fluctuation of IL-18 and interleukin-8 (IL-8) levels was detected, as was a negative correlation between the fluctuation of IL-18 and CXCL10 levels. The level of plasma C-C motif chemokine ligand 5 (CCL5) was significantly higher in patients with irAEs than in those without irAEs. CONCLUSIONS: Plasma cytokines are related to the clinical efficacy of PD-1/PD-L1 inhibitors. IL-18 and CXCL10 are potential predictive markers for anti-PD-1/PD-L1 therapy in lung cancer patients and may play an important role in selecting patients who would benefit from PD-1/PD-L1 inhibitors.

Identification of serum biomarkers to predict pemetrexed/platinum chemotherapy efficacy for advanced lung adenocarcinoma patients by data-independent acquisition (DIA) mass spectrometry analysis with parallel reaction monitoring (PRM) verification.

BACKGROUND: Pemetrexed/platinum chemotherapy has been the standard chemotherapy regimen for lung adenocarcinoma patients, but the efficacy varies considerably. METHODS: To discover new serum biomarkers to predict the efficacy of pemetrexed/platinum chemotherapy, we analyzed 20 serum samples from advanced lung adenocarcinoma patients who received pemetrexed/platinum chemotherapy with the data-independent acquisition (DIA) quantitative mass spectrometry (MS). RESULTS: The 20 patients were categorized as "good response" [12 patients achieving partial response (PR)] and "poor response" [8 patients with progressive disease (PD)] groups. Altogether 23 significantly different expressed proteins were identified, which had relative ratios higher than 1.2 or lower than -0.83, with 7 proteins having an area under the curve (AUC) above 0.8. To further validate the DIA results, we used the parallel reaction monitoring (PRM) method to examine 16 candidate serum biomarkers in the study cohort of 20 patients and another cohort of 22 advanced lung adenocarcinoma patients (16 PR and 6 PD). Quantitative validation using PRM correlated well with the DIA results, and 10 promising proteins exhibited a similar up- or downregulation. It is worth noting that glutathione peroxidase 3 (GPX3) exhibits significant upregulation in the poor response group compared with the good response group, which was validated by both DIA and PRM methods. CONCLUSIONS: Our study confirmed that combined DIA MS and PRM approaches were effective in identifying serum predictive biomarkers for advanced lung adenocarcinoma patients. Further studies are needed to explore the potential biological mechanism underlying these biomarkers.

Effects of cidofovir on human papillomavirus-positive cervical cancer cells xenografts in nude mice.

Cidofovir (CDV) is an acyclic nucleoside phosphonate analog that shows broad spectrum anti-DNA virus activity. In this study, we have investigated the influence of cidofovir on the tumor xenografts derived from HeLa and SiHa cells on nude mice. The HeLa/SiHa xenografts in nude mice were established by inoculating cells subcutaneously. Administration of cidofovir by intratumoral injection led to significant tumor reduction. Enhanced protein levels of p53 and p-pRb within the tumor samples were observed. Immunohistology analysis of the tumor sections indicated decreased PCNA index and increased apoptosis index. Our study gives more evidence and explanation on in vivo inhibition effect of cidofovir on HPV genome-positive cervical carcinoma cell line xenografts.

CHIP functions an E3 ubiquitin ligase of Runx1.

Runx1 is a key factor in the generation and maintenance of hematopoietic stem cells. Improper expression and mutations in Runx1 are frequently implicated in human leukemia. Here, we report that CHIP, the carboxyl terminus of Hsc70-interacting protein, also named Stub1, physically interacts with Runx1 through the TPR and Charged domains in the nucleus. Over-expression of CHIP directly induced Runx1 ubiquitination and degradation through the ubiquitin-proteasome pathway. Interestingly, we found that CHIP-mediated degradation of Runx1 is independent of the molecular chaperone Hsp70/90. Taken together, we propose that CHIP serves as an E3 ubiquitin ligase that regulates Runx1 protein stability via an ubiquitination and degradation mechanism that is independent of Hsp70/90.