Human recombinant Cripto-1 increases doubling time and reduces proliferation of HeLa cells independent of pro-proliferation pathways

Expression and prognostic value of Cripto-1 in early non-small cell lung cancer

OBJECTIVE

We aim to explore the expression of Cripto-1 (CR-1) protein in patients with early stage non-small cell lung cancer (NSCLC).

METHODS

We investigated CR-1 expression status in specimens obtained from 240 patients with resected NSCLC and 30 cases of para-carcinous normal lung tissues.

RESULTS

Compared with normal lung tissue, the positive expression of CR-1 protein in NSCLC was significantly increased (p < 0.005). Cox multivariate regression analysis showed that the expression of CR-1 protein was an independent prognostic factor for early stage NSCLC (p = 0.002).

CONCLUSION

Detecting CR-1 protein can predict the prognosis and recurrence in patients with NSCLC.

Organic Mass Cytometry Discriminating Cycle Stages of Single Cells with Small Molecular Indicators

Cell cycle is a significant factor toward cellular heterogeneity, so cell cycle discrimination is a precise measurement on the top of single-cell analysis. Single-cell analysis based on organic mass spectrometry has received great attention for its unique ability to profile single-cell metabolome, but the influence of cell cycle on cellular metabolome heterogeneity has been overlooked until now due to the lack of a compatible cell cycle discrimination method. Here, we report a robust protocol based on the combination of three small molecular indicators, consisting of two small molecular labels (Hoechst and docetaxel) and one cellular endogenous compound [phosphocholine (34:1)], to discriminate single cells at different cycle stages in real time by organic mass cytometry. More than 6000 HeLa cells were acquired by an improved organic mass cytometry system to build a cell cycle differentiation model. The model successfully discriminated single HeLa cells, SCC7, and Hep G2 cells, at G₀/G₁, S, and G₂/M stages with larger than 85% sensitivity and larger than 89% specificity. Along with cell cycle discrimination, obvious heterogeneity of amino acids, nucleotides, energy metabolic intermediates, and phospholipids was observed among single cells at different cycle stages by this protocol, further demonstrating the necessity of cell cycle discrimination for cellular metabolome heterogeneity research and the potential of more endogenous small molecular compounds for cell cycle discrimination.

Intra- and Inter-cellular Modeling of Dynamic Interaction between Zika Virus and Its Naturally Occurring Defective Viral Genomes

Here, we examine in silico the infection dynamics and interactions of two Zika virus (ZIKV) genomes: one is the full-length ZIKV genome (wild type [WT]), and the other is one of the naturally occurring defective viral genomes (DVGs), which can replicate in the presence of the WT genome, appears under high-MOI (multiplicity of infection) passaging conditions, and carries a deletion encompassing part of the structural and NS1 protein-coding region. Ordinary differential equations (ODEs) were used to simulate the infection of cells by virus particles and the intracellular replication of the WT and DVG genomes that produce these particles. For each virus passage in Vero and C6/36 cell cultures, the rates of the simulated processes were fitted to two types of observations: virus titer data and the assembled haplotypes of the replicate passage samples. We studied the consistency of the model with the experimental data across all passages of infection in each cell type separately as well as the sensitivity of the model's parameters. We also determined which simulated processes of virus evolution are the most important for the adaptation of the WT and DVG interplay in these two disparate cell culture environments. Our results demonstrate that in the majority of passages, the rates of DVG production are higher inC6/36 cells than in Vero cells, which might result in tolerance and therefore drive the persistence of the mosquito vector in the context of ZIKV infection. Additionally, the model simulations showed a slower accumulation of infected cells under higher activation of the DVG-associated processes, which indicates a potential role of DVGs in virus attenuation. IMPORTANCE One of the ideas for lessening Zika pathogenicity is the addition of its natural or engineered defective virus genomes (DVGs) (have no pathogenicity) to the infection pool: a DVG is redirecting the wild-type (WT)-associated virus development resources toward its own maturation. The mathematical model presented here, attuned to the data from interplays between WT Zika viruses and their natural DVGs in mammalian and mosquito cells, provides evidence that the loss of uninfected cells is attenuated by the DVG development processes. This model enabled us to estimate the rates of virus development processes in the WT/DVG interplay, determine the key processes, and show that the key processes are faster in mosquito cells than in mammalian ones. In general, the presented model and its detailed study suggest in what important virus development processes the therapeutically efficient DVG might compete with the WT; this may help in assembling engineered DVGs for ZIKV and other flaviviruses.

A single nuclear polymorphism in let-7g binding site affects the doubling time of thyroid nodule by regulating KRAS-induced cell proliferation

As an indicator for the malignancy of thyroid nodules (TN), the doubling time of TN was studied in this study to evaluate the effect of rs712 polymorphism on the progression of TN. In addition, we aimed to study the potential molecular mechanisms underlying the pathological effect of rs712 polymorphism upon TN. A Taqman method was used to genotype the patients according to their rs712 polymorphism. Real-time polymerase chain reaction, western blot, Terminal deoxynucleotidyl transferase dUTP nick end labeling assay and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium (MTT) assay was conducted to study the correlation between KRAS expression and the pathological effect of rs712 polymorphism. In-silicon analysis and luciferase assay were utilized to establish the regulatory relationship between let-7g and KRAS. KRAS messenger RNA (mRNA)/protein levels in the GG group were upregulated with a decreased apoptosis index. KRAS mRNA was validated to be a virtual target of let-7g. In addition, the mRNA/protein level of KRAS as well as cell proliferation index was decreased in primary thyroid cancer cells genotyped as TT/TG and transfected with KRAS small interfering RNA (siRNA)/let-7g precursors. The cell apoptosis index was evidently elevated in the KRAS siRNA/let-7g precursors group compared with that in the scramble controls. Moreover, KRAS mRNA/protein only showed slight reduction when GG-genotyped primary thyroid cancer cells were transfected by let-7g precursors. Additionally, let-7g precursors exhibited no significant effect on cell proliferation index or cell apoptosis in GG cells. Rs712 polymorphism T>G in the 3'-untranslated region of KRAS interrupts the interactions between let-7g and KRAS mRNA, leading to a higher cell proliferation index and reduced doubling time of TN.

Silk Sericin Hydrolysate is a Potential Candidate as a Serum-Substitute in the Culture of Chinese Hamster Ovary and Henrietta Lacks Cells

The silk sericin hydrolysate (SSH) from the waste of silk processing as a substitute of fetal bovine serum (FBS) was used for the culture of Chinese hamster ovary (CHO) cells and Henrietta Lacks (Hela) strain of human cervical cancer cells. The survival ratio of these cells cultured in SSH media were similar to or higher than those in FBS media. Especially after the serum was replaced by low concentration of SSH at 15.0 μg/ml for 5 d, the proliferation of both cells was also similar to or higher than that of FBS group; the percentages of CHO and Hela cells in S-phase were 28.9 and 28.0%, respectively. The former is nearly two times that of FBS group, the latter is also higher than the control group. Reverse transcription-polymerase chain reaction (RT-PCR) revealed that among the differentially expressed genes, the relative expression of CXCL12 gene of CHO cells in SSH group increased, was three times that of serum group, and the relative expression of LCN2 gene of Hela cells increased 2.8 times, indicating that these related genes were activated to promote cell growth and proliferation. These results fully illustrated the hydrolysated sericin has a potential use as serum substitutes in cell culture.

Exogenous Cripto-1 Suppresses Self-Renewal of Cancer Stem Cell Model

Cripto-1 is a glycophosphatidylinositol (GPI) anchored signaling protein of epidermal growth factor (EGF)-Cripto-1-FRL1-Cryptic (CFC) family and plays a significant role in the early developmental stages and in the different types of cancer cells, epithelial to mesenchymal transition and tumor angiogenesis. Previously, we have developed cancer stem cells (miPS-LLCcm) from mouse iPSCs by culturing them in the presence of conditioned medium of Lewis Lung Carcinoma (LLC) cells for four weeks. Nodal and Cripto-1 were confirmed to be expressed in miPS-LLCcm cells by quantitative reverse transcription PCR (rt-qPCR) implying that Cr-1 was required in maintaining stemness. To investigate the biological effect of adding exogenous soluble CR-1 to the cancer stem cells, we have prepared a C-terminally truncated soluble form of recombinant human CR-1 protein (rhsfCR-1), in which the GPI anchored moiety was removed by substitution of a stop codon through site-directed mutagenesis. rhsfCR-1 effectively suppressed the proliferation and sphere forming ability of miPS-LLCcm cells in a dose-dependent manner in the range of 0 to 5 µg/mL, due to the suppression of Nodal-Cripto-1/ALK4/Smad2 signaling pathway. Frequency of sphere-forming cells was dropped from 1/40 to 1/69 by rhsfCR-1 at 1 µg/mL. Moreover, rhsfCR-1 in the range of 0 to 1 µg/mL also limited the differentiation of miPS-LLCcm cells into vascular endothelial cells probably due to the suppression of self-renewal, which should reduce the number of cells with stemness property. As demonstrated by a soluble form of exogenous Cripto-1 in this study, the efficient blockade would be an attractive way to study Cripto-1 dependent cancer stem cell properties for therapeutic application.

Systematic evaluation of sericin protein as a substitute for fetal bovine serum in cell culture

Fetal bovine serum (FBS) shows obvious deficiencies in cell culture, such as low batch to batch consistency, adventitious biological contaminant risk, and high cost, which severely limit the development of the cell culture industry. Sericin protein derived from the silkworm cocoon has become increasingly popular due to its diverse and beneficial cell culture characteristics. However, systematic evaluation of sericin as a substitute for FBS in cell culture medium remains limited. In this study, we conducted cellular morphological, physiological, and transcriptomic evaluation on three widely used mammalian cells. Compared with cells cultured in the control, those cultured in sericin-substitute medium showed similar cellular morphology, similar or higher cellular overall survival, lower population doubling time (PDT), and a higher percentage of S-phase with similar G2/G1 ratio, indicating comparable or better cell growth and proliferation. At the transcriptomic level, differentially expressed genes between cells in the two media were mainly enriched in function and biological processes related to cell growth and proliferation, reflecting that genes were activated to facilitate cell growth and proliferation. The results of this study suggest that cells cultured in sericin-substituted medium perform as well as, or even better than, those cultured in FBS-containing medium.

Curcumin-docetaxel co-loaded nanosuspension for enhanced anti-breast cancer activity

PURPOSE

A curcumin-docetaxel co-loaded nanosuspension with increased anti-breast cancer activity was developed. Curcumin is a potential anticancer agent with p-glycoprotein (p-gp) inhibiting activity may be co-administered with docetaxel as a nanosuspension to enhance its anticancer effect by increasing the oral bioavailability and decreasing drug efflux.

METHODS

Nanosuspensions of curcumin and docetaxel were prepared by precipitation-homozenisation technique and evaluated for particle size, polydispersity, zeta potential and drug release. The in vitro MTT assay was conducted using MCF-7 for anti-breast cancer activity. The in vivo biodistribution by radiolabeling and tumor inhibition study was conducted in mice.

RESULTS

Homogenous nanosuspensions of 80 ± 20 nm were obtained with increased solubility. The drugs as nanosuspensions showed higher cytotoxicity on MCF-7 cell line compared to their suspensions due to the increased in vitro cellular uptake. Due to this increased solubility, sensitization of tumor cells and inhibition of p-gp the in-vivo results showed greater tumor inhibition rate of up to 70% in MCF-7 treated mice. Histopathological results showed higher apoptotic activity and reduced level of angiogenesis.

CONCLUSIONS

The in vitro and in vivo study of the nanosuspensions has shown that Co-administration of Curcumin as a p-gp inhibitor with docetaxel may have the potential to increase the anti-breast cancer efficacy of both drugs.

CRIPTO overexpression promotes mesenchymal differentiation in prostate carcinoma cells through parallel regulation of AKT and FGFR activities

Members of the EGF-CFC (Cripto, FRL-1, Cryptic) protein family are increasingly recognized as key mediators of cell movement and cell differentiation during vertebrate embryogenesis. The founding member of this protein family, CRIPTO, is overexpressed in various human carcinomas. Yet, the biological role of CRIPTO in this setting remains unclear. Here, we find CRIPTO expression as especially high in a subgroup of primary prostate carcinomas with poorer outcome, wherein resides cancer cell clones with mesenchymal traits. Experimental studies in PCa models showed that one notable function of CRIPTO expression in prostate carcinoma cells may be to augment PI3K/AKT and FGFR1 signaling, which promotes epithelial-mesenchymal transition and sustains a mesenchymal state. In the observed signaling events, FGFR1 appears to function parallel to AKT, and the two pathways act cooperatively to enhance migratory, invasive and transformation properties specifically in the CRIPTO overexpressing cells. Collectively, these findings suggest a novel molecular network, involving CRIPTO, AKT, and FGFR signaling, in favor of the emergence of mesenchymal-like cancer cells during the development of aggressive prostate tumors.

Cripto-1 Promotes the Epithelial-Mesenchymal Transition in Esophageal Squamous Cell Carcinoma Cells

Esophageal carcinoma is a major public health problem worldwide and one of the most aggressively malignant neoplasms. Although considerable diagnostic and therapeutic progress has been made in recent years, the prognosis of EC patients still remains dismal due to high rates of recurrence/metastasis and invasion. Previous studies have demonstrated that Epithelial mesenchymal transition (EMT) is proposed as a critical mechanism for the acquisition of malignant phenotypes by epithelial cells. Several lines of evidence have shown that Cripto-1 plays an important oncogenic role during tumorigenesis by promoting EMT. The aim of our study was to evaluate the significance of Cripto-1 which plays a role in EMT and its metastasis in esophageal carcinoma. Data of this study suggest that Cripto-1 overexpression is connected with the tumorigenesis and progression of esophageal carcinoma; shRNA might be feasible for the inhibition of the invasion and metastasis of esophageal carcinoma.

Autoregulation and heterogeneity in expression of human Cripto-1

Cripto-1 (CR-1) is involved in various processes in embryonic development and cancer. Multiple pathways regulate CR-1 expression. Our present work demonstrates a possible positive feedback circuit where CR-1 induces its own expression. Using U-87 MG cells treated with exogenous CR-1, we show that such induction involves ALK4/SMAD2/3 pathway. Stochasticity in gene expression gives rise to heterogeneity in expression in genetically identical cells. Positive feedback increases such heterogeneity and often gives rise to two subpopulations of cells, having higher and lower expression of a gene. Using flow cytometry, we show that U-87 MG cells have a minuscule subpopulation with detectable expression of CR-1. Induction of CR-1 expression, by exogenous CR-1, increases the size of this CR-1 positive subpopulation. However, even at very high dose, most of the cells remain CR-1 negative. We show that population behavior of CR-1 induction has a signature similar to bimodal expression expected in a transcriptional circuit with positive feedback. We further show that treatment of U-87 MG cells with CR-1 leads to higher expression of drug efflux protein MDR-1 in the CR-1 positive subpopulation, indicating correlated induction of these two proteins. Positive feedback driven heterogeneity in expression of CR-1 may play crucial role in phenotypic diversification of cancer cells.

CXCL12/CXCR4 axis confers adriamycin resistance to human chronic myelogenous leukemia and oroxylin A improves the sensitivity of K562/ADM cells

This study was aimed at investigating the reversal effect of oroxylin A, a naturally bioactive monoflavonoid separated and purified from Scutellaria baicalensis Georgi, in human chronic myeloid leukemia (CML) and the underlying mechanisms. The results showed that CXCL12 could enhance the resistance of K562 cells to adriamycin (ADM) by increasing the expression of CXCR4, up-regulating the downstream PI3K/Akt pathway, and promoting translocation of NF-κB dimers into nucleus and subsequently decreasing the expression of apoptosis-related proteins in K562 cells. And we found that ADM resistance was partially reversed by CXCR4 siRNA transfection. Moreover, the sensitivity enhancement of oroxylin A was demonstrated by decreasing the expression of CXCR4 at both protein and mRNA levels, via PI3K/Akt/NF-κB pathway and triggering the apoptosis pathway in vitro. In addition, the in vivo study showed that oroxylin A increased apoptosis of leukemic cells with low systemic toxicity, and the mechanism was the same as in vitro study. In conclusion, all these results showed that oroxylin A improved the sensitivity of K562/ADM cells by increasing apoptosis in leukemic cells and decreasing the expression of CXCR4 and PI3K/Akt/NF-κB pathway, and probably served as a most promising agent for CML treatment.

Tubeless biochip for chemical stimulation of cells in closed-bioreactors: anti-cancer activity of the catechin–dextran conjugate

Here we introduce a tubeless microbioreactor for chemically stimulation of cells in microchambers, based on automatic cell valving, hydrostatic-pressure pumping and on-chip liquid reservoirs.

Amelioration of cancer stem cells in macrophage colony stimulating factor-expressing U87MG-human glioblastoma upon 5-fluorouracil therapy

Macrophage colony stimulating factor (MCSF) regulates growth, proliferation and differentiation of haematopoietic cell lineages. Many cancers are known to secrete high level of MCSF, which recruit macrophages into the tumour micro-environment, supporting tumour growth. Herein, we report the cloning of MCSF and subsequent generation of U87MG expressing MCSF stable cell line (U87-MCSF). Cytotoxicity of anti-cancer drug 5-fluorouracil (5-FU) was evaluated on both U87MG and U87-MCSF cells. Interestingly, the proliferation of U87-MCSF cells was less (p<0.001) than that of U87MG cells alone, after treatment with 5-FU. Significant decrease in expression levels of cyclin E and A2 quantified by real time PCR analysis corroborated the reduced proliferation of 5-FU treated U87-MCSF cells. However, JC-1 staining did not reveal any apoptosis upon 5-FU treatment. Notch-1 upregulation induced a possible epithelial-mesenchymal transition in U87-MCSF cells, which accounted for an increase in the proportion of CD24^high/CD44^less cancer stem cells in U87-MCSF cells after 5-FU treatment. The elevated resistance of U87-MCSF cells towards 5-FU was due to the increase in the expressions (10.2 and 6 fold) of ABCB1 and mdm2, respectively. Furthermore, increase in expressions of ABCG1, mdm2 and CD24 was also observed in U87MG cells after prolonged incubation with 5-FU. Our studies provided mechanistic insights into drug resistance of U87MG cells and also described the pivotal role played by MCSF in augmenting the resistance of U87MG cells to 5-FU.