An Assessment of the Utility of Tissue Smears in Rapid Cancer Profiling with Desorption Electrospray Ionization Mass Spectrometry (DESI-MS)

Mass spectrometry imaging with desorption electrospray ionization mass spectrometry (DESI-MS) is used to characterize cancer from ex vivo slices of tissues. The process is time-consuming. The use of tissue smears for DESI-MS analysis has been proposed as it eliminates the time required to snap-freeze and section the tissue. To assess the utility of tissue smears for rapid cancer characterization, principal component analysis (PCA) was performed to evaluate the concordance between DESI-MS profiles of breast cancer from tissue slices and smears prepared on various surfaces. PCA suggested no statistical discrimination between DESI-MS profiles of tissue sections and tissue smears prepared on glass, polytetrafluoroethylene (PTFE), and porous PTFE. However, the abundances of cancer biomarker ions varied between sections and smears, with DESI-MS analysis of tissue sections yielding higher ion abundances of cancer biomarkers compared with smears. Coefficient of variance (CV) analysis suggests DESI-MS profiles from tissue smears are as reproducible as the ones from tissue sections. The limit of detection with smear samples from single pixel analysis is comparable to tissue sections that average the signal from a tissue area of 0.01 mm². The smears prepared on the PTFE surface possessed a higher degree of homogeneity compared with the smears prepared on the glass surface. This allowed single MS scans (~1 s) from random positions across the surface of the smear to be used in rapid cancer typing with good reproducibility, providing pathologic information for cancer typing at speeds suitable for clinical utility. Graphical Abstract ᅟ.

Circulating Tumor Cells: Markers and Methodologies for Enrichment and Detection

Cancer is a leading cause of disease worldwide; however, nowadays many points of its initiation processes are unknown. In this chapter, we are focusing on the role of liquid biopsies in cancer detection and progression. CTCs are one of the main components of liquid biopsies, they represent a subset of tumor cells that have acquired the ability to disseminate from the primary tumor and intravasate to the circulatory system. The greatest challenge in the detection of CTCs is their rarity in the blood. Human blood consists of white blood cells (5-10 × 10⁶/mL), red blood cells (5-9 × 10⁹/mL), and platelets (2.5-4 × 10⁸/mL); very few CTCs will be present even in patients with known metastatic disease, with often less than one CTC per mL of blood. CTCs are found in frequencies on the order of 1-10 CTCs per mL of whole blood in patients with metastatic disease, and it is reduced in half for non-metastatic stages. Therefore, accurate methodologies for their capture and analysis are really important. The main aim of the present chapter is to describe different methodologies for CTCs capturing and analysis.

Digital PCR Improves Mutation Analysis in Pancreas Fine Needle Aspiration Biopsy Specimens

Applications of precision oncology strategies rely on accurate tumor genotyping from clinically available specimens. Fine needle aspirations (FNA) are frequently obtained in cancer management and often represent the only source of tumor tissues for patients with metastatic or locally advanced diseases. However, FNAs obtained from pancreas ductal adenocarcinoma (PDAC) are often limited in cellularity and/or tumor cell purity, precluding accurate tumor genotyping in many cases. Digital PCR (dPCR) is a technology with exceptional sensitivity and low DNA template requirement, characteristics that are necessary for analyzing PDAC FNA samples. In the current study, we sought to evaluate dPCR as a mutation analysis tool for pancreas FNA specimens. To this end, we analyzed alterations in the KRAS gene in pancreas FNAs using dPCR. The sensitivity of dPCR mutation analysis was first determined using serial dilution cell spiking studies. Single-cell laser-microdissection (LMD) was then utilized to identify the minimal number of tumor cells needed for mutation detection. Lastly, dPCR mutation analysis was performed on 44 pancreas FNAs (34 formalin-fixed paraffin-embedded (FFPE) and 10 fresh (non-fixed)), including samples highly limited in cellularity (100 cells) and tumor cell purity (1%). We found dPCR to detect mutations with allele frequencies as low as 0.17%. Additionally, a single tumor cell could be detected within an abundance of normal cells. Using clinical FNA samples, dPCR mutation analysis was successful in all preoperative FNA biopsies tested, and its accuracy was confirmed via comparison with resected tumor specimens. Moreover, dPCR revealed additional KRAS mutations representing minor subclones within a tumor that were not detected by the current clinical gold standard method of Sanger sequencing. In conclusion, dPCR performs sensitive and accurate mutation analysis in pancreas FNAs, detecting not only the dominant mutation subtype, but also the additional rare mutation subtypes representing tumor heterogeneity.

Targeting Promoter-Associated Noncoding RNA In Vivo

There are many classes of noncoding RNAs (ncRNAs), with wide-ranging functionalities (e.g., RNA editing, mediation of mRNA splicing, ribosomal function). MicroRNAs (miRNAs) and long ncRNAs (lncRNAs) are implicated in a wide variety of cellular processes, including the regulation of gene expression. Incorrect expression or mutation of lncRNAs has been reported to be associated with several disease conditions, such a malignant transformation in humans. Importantly, pivotal players in tumorigenesis and cancer progression, such as c-Myc, may be regulated by lncRNA at promoter level. The function of lncRNA can be reduced with antisense oligonucleotides that sequester or degrade mature lncRNAs. In alternative, lncRNA transcription can be blocked by small interference RNA (RNAi), which had acquired, recently, broad interested in clinical applications. In vivo-jetPEI™ is a linear polyethylenimine mediating nucleic acid (DNA, shRNA, siRNA, oligonucelotides) delivery with high efficiency. Different in vivo delivery routes have been validated: intravenous (IV), intraperitoneal (IP), intratumoral, subcutaneous, topical, and intrathecal. High levels of nucleic acid delivery are achieved into a broad range of tissues, such as lung, salivary glands, heart, spleen, liver, and prostate upon systemic administration. In addition, in vivo-jetPEI™ is also an efficient carrier for local gene and siRNA delivery such as intratumoral or topical application on the skin. After systemic injection, siRNA can be detected and the levels can be validated in target tissues by qRT-PCR. Targeting promoter-associated lncRNAs with siRNAs (small interfering RNAs) in vivo is becoming an exciting breakthrough for the treatment of human disease.

IDENTIFYING CANCER SPECIFIC METABOLIC SIGNATURES USING CONSTRAINT-BASED MODELS

Cancer metabolism differs remarkably from the metabolism of healthy surrounding tissues, and it is extremely heterogeneous across cancer types. While these metabolic differences provide promising avenues for cancer treatments, much work remains to be done in understanding how metabolism is rewired in malignant tissues. To that end, constraint-based models provide a powerful computational tool for the study of metabolism at the genome scale. To generate meaningful predictions, however, these generalized human models must first be tailored for specific cell or tissue sub-types. Here we first present two improved algorithms for (1) the generation of these context-specific metabolic models based on omics data, and (2) Monte-Carlo sampling of the metabolic model ux space. By applying these methods to generate and analyze context-specific metabolic models of diverse solid cancer cell line data, and primary leukemia pediatric patient biopsies, we demonstrate how the methodology presented in this study can generate insights into the rewiring differences across solid tumors and blood cancers.

TaqMan Low Density Array: MicroRNA Profiling for Biomarker and Oncosuppressor Discovery

MicroRNAs (miRNAs) have gained a lot of interest as biomarkers and biotherapeutics in recent years. The discovery of miRNAs in circulation as recently as 2008, aided by rapid advances in high-throughput profiling techniques initiated an explosion of investigations dedicated to discovering circulating miRNAs as minimally invasive biomarkers. As miRNAs regulate many cellular processes, investigators are actively exploring their relevance in disease treatment by miRNA restoration. This chapter demonstrates an approach to discover miRNAs of biomarker and therapeutic potential by isolating miRNAs from cell lines, performing global miRNA profiling, investigating miRNA expression in clinical specimens and examining their therapeutic relevance by restoring miRNA expression using Lipofectamine in vitro.

Deconstructing the Metabolic Networks of Oncogenic Signaling Using Targeted Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS)

Metabolic reprogramming is recognized as an emerging hallmark of oncogenic signaling and cancer development. Hence the need to identify novel quantitative analytical platforms for studying metabolism in vitro and in vivo has dramatically increased. Here, we describe the experimental workflow for a targeted liquid chromatography-tandem mass spectrometry (LC-MS/MS) approach involving positive/negative ion switching to analyze >250 metabolites of central carbon metabolism, nucleotides, and amino acids.

Gene Silencing Using Multifunctionalized Gold Nanoparticles for Cancer Therapy

Multifunctionalized gold nanobeacons (Au-nanobeacon) combine, in a single and unique platform, targeting, detection and silencing providing an effective impact in clinics boosting cancer theranostics. Here, we describe a nano-integrated platform based on Au-nanobeacons able to detect and inhibit gene expression specifically in cancer cells. The surfaces of gold nanoparticles (AuNPs) are functionalized with targeting peptides to enhance tumor cell recognition and uptake, and with fluorescently labeled antisense DNA hairpin oligonucleotides to detect AuNPs. These oligonucleotides, upon recognition and hybridization to the target, open their structure resulting in separating apart the dye and the quencher allowing the fluorophore to emit light and to monitor the intracellular interactions of AuNPs with the target and the specific silencing of gene expression. This strategy allows inhibiting KRAS gene expression in colorectal carcinoma cell lines with no relevant toxicity for healthy fibroblasts. Importantly, this nano-integrated platform can be easily adapted to hybridize with any specific target thus providing real benefits for the diagnosis and treatment of cancer.

Inhibition of hepatitis C virus using siRNA targeted to the virus and Hsp90

Hepatitis C (HCV) is a viral disease affecting millions of people worldwide, and persistent HCV infection can lead to progressive liver disease with the development of liver cirrhosis and hepatocellular carcinoma. During treatment for hepatitis C, the occurrence of viral resistance is common. To reduce the occurrence of resistance, new viral treatments should target both viral and cellular factors. Many interactions occur between viral and host proteins during the HCV replication cycle and might be used for the development of new therapies against hepatitis C. Heat shock protein 90 (Hsp90) plays a role in the folding of cellular and viral proteins and also interacts with HCV proteins. In the present study, we knocked down the expression of the Hsp90 gene and inhibited viral replication using siRNA molecules. Reducing the expression of Hsp90 successfully decreased HCV replication. All siRNA molecules specific to the viral genome showed the efficient inhibition of viral replication, particularly siRNA targeted to the 5'UTR region. The combination of siRNAs targeting the viral genome and Hsp90 mRNA also successfully reduced HCV replication and reduced the occurrence of viral resistance. Moreover, these results suggest that an approach based on the combination of cellular and viral siRNAs can be used as an effective alternative for hepatitis C viral suppression.

Phage display-derived oligopeptide-functionalized probes for in vivo specific photoacoustic imaging of osteosarcoma

Specific detection of various tumor types remains crucial for designing effective treatment strategies. We demonstrate photoacoustic imaging (PAI) using high-affinity and high-specificity peptide-based probes for accurate and specific diagnosis of osteosarcoma. Herein, two new tumor-specific oligopeptides, termed PT6 and PT7, were identified using phage display-based screening on an osteosarcoma cell line (UMR-106). The identified oligopeptides were able to detect clinical osteosarcoma samples on tissue microarrays. Oligopeptide-conjugated PEGylated gold nanorods (PGNR) were designed to specifically target UMR-106 cells. More importantly, PAI revealed that both PGNR-PT6 and PGNR-PT7 could bind selectively to subcutaneous UMR-106 xenografts after systemic administration and enhance the contrast of osteosarcoma images by 170% and 230%, respectively, compared to tumor-bearing mice injected with PGNRs conjugated to scrambled oligopeptides. PAI employing PGNRs conjugated to specifically designed nanoprobes may provide a new method for tumor type-specific diagnosis of osteosarcoma.

Radiosensitization by the ATR Inhibitor AZD6738 through Generation of Acentric Micronuclei

AZD6738 is an orally active ATR inhibitor (ATRi) currently in phase I clinical trials. We found in vitro growth inhibitory activity of this ATRi in a panel of human cancer cell lines. We demonstrated radiosensitization by AZD6738 to single radiation fractions in multiple cancer cell lines independent of both p53 and BRCA2 status by the clonogenic assay. Radiosensitization by AZD6738 to clinically relevant doses of fractionated radiation was demonstrated in vitro using a 3D tumor spheroid model and, in vivo, AZD6738 radiosensitized by abrogating the radiation-induced G2 cell-cycle checkpoint and inhibiting homologous recombination. Mitosis with damaged DNA resulted in mitotic catastrophe as measured by micronucleus formation by live-cell fluorescent-ubiquitination cell-cycle imaging of cell-cycle progression and nuclear morphology. Induction of micronuclei was significantly more prominent for AZD6738 compared with inhibition of the downstream kinase CHK1 alone at isoeffective doses. Micronuclei were characterized as acentric chromosomal fragments, which displayed characteristics of increased DNA damage and cell-cycle dyssynchrony when compared with the primary nucleus. Mol Cancer Ther; 16(1); 25-34. ©2016 AACR.

Structure and Recognition of a Novel HIV-1 gp120-gp41 Interface Antibody that Caused MPER Exposure through Viral Escape

A comprehensive understanding of the regions on HIV-1 envelope trimers targeted by broadly neutralizing antibodies may contribute to rational design of an HIV-1 vaccine. We previously identified a participant in the CAPRISA cohort, CAP248, who developed trimer-specific antibodies capable of neutralizing 60% of heterologous viruses at three years post-infection. Here, we report the isolation by B cell culture of monoclonal antibody CAP248-2B, which targets a novel membrane proximal epitope including elements of gp120 and gp41. Despite low maximum inhibition plateaus, often below 50% inhibitory concentrations, the breadth of CAP248-2B significantly correlated with donor plasma. Site-directed mutagenesis, X-ray crystallography, and negative-stain electron microscopy 3D reconstructions revealed how CAP248-2B recognizes a cleavage-dependent epitope that includes the gp120 C terminus. While this epitope is distinct, it overlapped in parts of gp41 with the epitopes of broadly neutralizing antibodies PGT151, VRC34, 35O22, 3BC315, and 10E8. CAP248-2B has a conformationally variable paratope with an unusually long 19 amino acid light chain third complementarity determining region. Two phenylalanines at the loop apex were predicted by docking and mutagenesis data to interact with the viral membrane. Neutralization by CAP248-2B is not dependent on any single glycan proximal to its epitope, and low neutralization plateaus could not be completely explained by N- or O-linked glycosylation pathway inhibitors, furin co-transfection, or pre-incubation with soluble CD4. Viral escape from CAP248-2B involved a cluster of rare mutations in the gp120-gp41 cleavage sites. Simultaneous introduction of these mutations into heterologous viruses abrogated neutralization by CAP248-2B, but enhanced neutralization sensitivity to 35O22, 4E10, and 10E8 by 10-100-fold. Altogether, this study expands the region of the HIV-1 gp120-gp41 quaternary interface that is a target for broadly neutralizing antibodies and identifies a set of mutations in the gp120 C terminus that exposes the membrane-proximal external region of gp41, with potential utility in HIV vaccine design.

Human cytomegalovirus infection downregulates vitamin-D receptor in mammalian cells

Vitamin D (VD) is essential for the human body and involved in a wide variety of critical physiological processes including bone, muscle, and cardiovascular health, as well as innate immunity and antimicrobial responses. Here, we elucidated the significance of the VD system in cytomegalovirus (CMV) infection, which is one of the most common opportunistic infections in immunocompromised or -suppressed patients. We found that expression of vitamin D receptor (VDR) was downregulated in CMV-infected cells within 12h [hrs] post infection [p.i.] to 12% relative to VDR expression in mock-infected fibroblasts and did not recover during the CMV replication cycle of 96h. None of the biologically active metabolites of VD, cholecalciferol, calcidiol, or calcitriol, inhibit CMV replication significantly in human fibroblasts. In a feedback loop, expression of CYP24A1 dropped to 3% by 12h p.i. and expression of CYP27B1 increased gradually during the replication cycle of CMV to 970% probably as a consequence of VDR inhibition. VDR expression was not downregulated during influenza virus or adenovirus replication. The potent synthetic vitamin D analog EB-1089 was not able to inhibit CMV replication or antagonize its effect on VDR expression. Only CMV replication, and none of the other viral pathogens evaluated, inhibited the vitamin D system in vitro. In view of the pleiotropism of VDR, CMV-mediated downregulation may have far-reaching virological, immunological, and clinical implications and thus warrant further evaluations in vitro and in vivo.

New 2-Imino-2H-Chromene-3(N-aryl)carboxamides as Potential Cytotoxic Agents

Synthesis and structure activity relationships of four series of novel 2-imino-2H-chromene-3(N-aryl) carboxamides (V-VIII) have been described by bioisosteric replacement of usually present ketone at 2nd position of coumarin with imine. Various substitutents are introduced on aryl and chromene ring of iminocoumarin to investigate the effect of lipophilicity and electronic properties of substituents on cytotoxic activity against four human cancer cell lines. Novel 2-imino-2H-chromene-3(N-aryl)carboxamides (V-VIII) were synthesized by the reaction of substituted 2- cyanoacetamides with different salicyaldehydes in the presence of sodium acetate in glacial acetic acid. Compound VIa showed potent activity against MCF-7 (IC50 = 8.5 μM), PC-3 (IC50 = 35.0 μM), A-549 (IC50 = 0.9 μM) and Caco-2 (IC50 = 9.9 μM) cell lines. The anticancer results revealed that most of the synthesized compounds showed equipotent activity with the standard 5-fluorouracil and docetaxel on Caco-2 and MCF-7 cell lines, respectively.

[Cucurbitacin I (JSI-124)-induced apoptosis of HepG2 cells via p53 signaling pathway]

Objective To study the mechanism underlying cucurbitacin I (JSI-124) inducing cell apoptosis in human hepatoma HepG2 cells. Methods HepG2 cells were exposed to 0.01, 0.10, 1.00 and 10.00 μmol/L JSI-124 for 24, 48 and 72 hours. Cell proliferation was detected by CCK-8 assay; the nuclear morphological changes were observed by Hoechst 33258 staining; the formation of tumor cell colonies was visualized by violet staining; and cell apoptosis was detected by annexin V-FITC/PI double staining combined with flow cytometry. Furthermore, the mRNA expression levels of p53 and its downstream Bax, Fas and MDM2 genes were measured by quantitative real-time PCR, and the protein levels of P53 and activated caspase-3 were evaluated by Western blotting. Results JSI-124 inhibited the proliferation and induced Hoechst 33258-stained chromatin condensation in HepG2 cells in a concentration- and time-dependent manner. Flow cytometry revealed that 1.00 μmol/L JSI-124 treatment increased the apoptotic rate significantly in HepG2 cells compared with the control cells. Furthermore, JSI-124 significantly enhanced the mRNA expressions of p53 and its downstream apoptotic factors, including Bax and Fas, but did not change the gene expression of the p53 tumor suppressor, MDM2. The 48-hour treatment of JSI-124 in HepG2 cells significantly increased the levels of p53 and cleaved caspase-3 proteins. Conclusion JSI-124 induces the apoptosis of HepG2 cells through the activation of p53 and its downstream pro-apoptotic factors.

HOXA13 upregulation in gastric cancer is associated with enhanced cancer cell invasion and epithelial-to-mesenchymal transition

OBJECTIVE

In this study, we investigated the association between HOXA13 dysregulation and gastric cancer progression. We also explored the functional role of HOXA13 in invasion and epithelial-to-mesenchymal transition (EMT) of gastric cancer cells and the possible signaling pathway it might involve in.

MATERIALS AND METHODS

The microarray (E-GEOD-19826) examined the transcription profiles of 12 adjacent normal/tumor-matched gastric tissues was downloaded from the ArrayExpress and reanalyzed. Immunohistochemistry (IHC) staining was performed to assess HOXA13 expression in 23 stage I and 69 stage II/III/IV gastric cancer tissues. The human gastric cancer cell line AGS and SGC-7901 cells were transfected with HOXA13 siRNA and then were subjected to detection of epithelial and mesenchymal markers and cell invasion. The involvement of HOXA13 in TGF-β signaling was further studied.

RESULTS

HOXA13 is one of the most upregulated genes in gastric cancer tissues compared to adjacent normal tissues. Also, HOXA13 is further upregulated in the higher stage tumors. HOXA13 staining was significantly stronger in stage II/III/IV tumors than in stage I tumors. HOXA13 siRNA significantly restored the epithelial property and reduced the mesenchymal property of the cancer cells. Transwell assay showed that HOXA13 siRNA impaired the invasion capability of the cancer cells. The gastric cancer cells with HOXA13 knockdown had decreased expression of p-SMAD2 and p-SMAD3.

CONCLUSIONS

This study provides additional evidence about the association between HOXA13 upregulation and gastric cancer progression. Also, we showed that HOXA13 contributes to invasion and EMT of gastric cancer cells via the TGF-b signaling pathway.

Anticarcinogenic effect of Umbelliferone in human prostate carcinoma: An in vitro study

PURPOSE

To explore the chemoprotective effect of umbelliferone (UF) on prostate cancer cell lines, i.e. primary stage (LnCap) and last stage (PC3) prostate cancer together with the effect on the induction of apoptosis and alteration on cell cycle arrest.

METHODS

Various concentrations of UF were evaluated against the different prostate cancer cell lines. Lipopolysaccharide (LPS) induced cytokines related factor profiling, proinflammatory cytokines, and inflammatory mediators were studied using Western blot analysis.

RESULTS

UF showed significant apoptotic effect. Moreover, treatment with UF did not show apoptosis or cell cycle arrest on the non-cancerous cells including BHP-1, suggesting a selective tumor cell specific effect. UF treatment also enhanced the expression of Bax in PC3 cells, but had no significant effect on the activation of nuclear factor κB (NF-κB). Thus, the apoptosis induction was independent of NF-κB activation.

CONCLUSION

The results of the present investigation confirmed the chemoprotective effect of UF in early-stage (Ln- Cap) and late-stage (PC3) prostate cancer cells.

Bioinformatics Meets Biomedicine: OncoFinder, a Quantitative Approach for Interrogating Molecular Pathways Using Gene Expression Data

We propose a biomathematical approach termed OncoFinder (OF) that enables performing both quantitative and qualitative analyses of the intracellular molecular pathway activation. OF utilizes an algorithm that distinguishes the activator/repressor role of every gene product in a pathway. This method is applicable for the analysis of any physiological, stress, malignancy, and other conditions at the molecular level. OF showed a strong potential to neutralize background-caused differences between experimental gene expression data obtained using NGS, microarray and modern proteomics techniques. Importantly, in most cases, pathway activation signatures were better markers of cancer progression compared to the individual gene products. OF also enables correlating pathway activation with the success of anticancer therapy for individual patients. We further expanded this approach to analyze impact of micro RNAs (miRs) on the regulation of cellular interactome. Many alternative sources provide information about miRs and their targets. However, instruments elucidating higher level impact of the established total miR profiles are still largely missing. A variant of OncoFinder termed MiRImpact enables linking miR expression data with its estimated outcome on the regulation of molecular processes, such as signaling, metabolic, cytoskeleton, and DNA repair pathways. MiRImpact was used to establish cancer-specific and cytomegaloviral infection-linked interactomic signatures for hundreds of molecular pathways. Interestingly, the impact of miRs appeared orthogonal to pathway regulation at the mRNA level, which stresses the importance of combining all available levels of gene regulation to build a more objective molecular model of cell.

Stimulation of cellular senescent processes, including secretory phenotypes and anti-oxidant responses, after androgen deprivation therapy in human prostate cancer

Endocrine resistance is a major problem in prostate cancer. Recent studies suggest that cellular plasticity plays a key role in therapy resistance. Yet little is known about the cellular changes of human prostate cancer after androgen deprivation therapy (ADT). In this study, we investigated cellular senescence, senescence-associated secretory phenotypes (SASPs), and anti-oxidant responses. Hormone ablation upregulated senescence-associated (SA)-β-Gal activity in prostate glands, as well as the expressions of p27^KIP1 and p53, in a mouse castration model. In line with this, the expressions of p21^CIP1 and p27^KIP1 were significantly more upregulated in human non-pathological prostatic glands after ADT than in untreated specimens. In a study of SASP markers, the expressions of IL6 and IL8 were also more upregulated in human non-pathological prostatic glands after ADT than in untreated specimens. IL6, IL8, and MMP2 were expressed more strongly in human prostate cancer specimens resected after ADT than in untreated tumors. Of note, treatment with the anti-oxidant reagent NAC significantly suppressed SA-β-Gal activity in androgen-sensitive human prostate cancer LNCaP cells. In immunohistochemical analyses on anti-oxidant response genes, NRF2 and NQO1 were more upregulated after hormone ablation in human prostate gland and carcinoma specimens after ADT than in untreated specimens or in murine prostate glands after castration. Taken together, these findings suggest that ADT induces cellular senescence processes accompanied by secretory phenotypes and anti-oxidant responses in prostate. These cellular changes may be attractive targets for preventing endocrine resistance in prostate cancer.

Generation and Assessment of Fusions Between HDACi and TKi

Chimeric compounds combine the structural features of inhibitors of histone deacetylases (HDACi) and tyrosine kinase inhibitors (TKi), and therefore unite the effects of a dual-targeting strategy in one compound. Here, we describe the generation of such hybrid molecules. Small molecules, known as TKi, are combined with a Zn²⁺ chelating motive, preferentially a hydroxamic acid, in addition. The resulting small molecules also can inhibit histone deacetylases, which are dependent on the catalytically active Zn²⁺. Moreover, we summarize how the growth-inhibitory effects of these combined compounds can be determined with a simple proliferation assay with a leukemic cell line.

Concerted action of histone methyltransferases G9a and PRMT-1 regulates PGC-1α-RIG-I axis in IFNγ treated glioma cells

IFNγ induced de-differentiation markers are negatively regulated by retinoic acid inducible gene (RIG-I) in glioma cells. In addition to RIG-I, IFNγ treatment increased H3K9me2; histone methyltransferases (HMTs) G9a and protein arginine methyltransferase-1 (PRMT-1) levels. While G9a inhibition further increased IFNγ induced RIG-I, PRMT-1 inhibition abrogated IFNγ elevated RIG-I levels. IFNγ induced Sp1 and NFκB served as negative regulators of RIG-I, with decreased occupancy of Sp1 and NFκB observed on the RIG-I promoter. A diminished H3K9Me2 enrichment was observed at the NFκB but not at Sp-1 binding site. IFNγ induced PPAR gamma coactivator-1 alpha (PGC-1α) positively regulated RIG-I; with PRMT-1 and G9a affecting PGC-1α in a counter-regulatory manner. These findings demonstrate how concerted action of HMTs aid PGC-1α driven RIG-I for the sustenance of glioma cells in a de-differentiated state.

Glyceraldehyde-3-phosphate dehydrogenase promotes cancer growth and metastasis through upregulation of SNAIL expression

Glyceraldehyde-3-phosphate dehydrogenase (GAPDH) plays an important role in multiple cellular functions including metabolism and gene transcription. Our previous study showed that GAPDH expression was elevated in colon cancer and further upregulated in liver metastatic tissues, suggesting a possilbe role of GAPDH in promoting cancer metastasis. The present study was designed to investigate the underlying mechanism, using multiple experimental approaches including genetic silencing of GAPDH expression by short hairpin RNA (shRNA) and biochemcial/molecular analyses of the key events involved in glycolytic metabolism and epithelial-mesenchymal transition (EMT). We showed that silencing of GAPDH expression resulted in a significant reduction of glycolysis in colon cancer cell lines, accompanied by a decrease in cell proliferation and an apparent change in cell morphology associated with alterations in actin expression and phalloidine staining patterns. Furthermore, GAPDH suppression also caused a downregulation of gene expression involved in cancer stem-like cells and EMT. CHIP assay and co-immunoprecipitation revealed that GAPDH physically interacted with the transcriptional factor Sp1 and enhance the expression of SNAIL, a major regulator of EMT. Suppression of GAPDH expression resulted in a signficant decrease in SNAIL expression, leading to inhibition of EMT and attenuation of colon cancer cell migration in vitro and reduced metastasis in vivo. Overall, the present study suggests that GAPDH plays an important role in cancer metastasis by affecting EMT through regulation of Sp1-mediated SNAIL expression.

Differential effects of the enantiomers of tamsulosin and tolterodine on P-glycoprotein and cytochrome P450 3A4

The pregnane X receptor (PXR) is a transcription factor regulating P-glycoprotein (P-gp; ABCB1)-mediated transport and cytochrome P450 3A4 (CYP3A4)-mediated metabolism of xenobiotics thereby affecting the pharmacokinetics of many drugs and potentially modulating clinical efficacy. Thus, pharmacokinetic drug-drug interactions can arise from PXR activation. Here, we examined whether the selective α1-adrenoreceptor blocker tamsulosin or the antagonist of muscarinic receptors tolterodine affect PXR-mediated regulation of CYP3A4 and of P-gp at the messenger RNA (mRNA) and protein level in an enantiomer-specific way. In addition, the effect of tamsulosin and tolterodine on P-gp activity was evaluated. We used quantitative real-time PCR, gene reporter assay, western blotting, rhodamine efflux assay, and calcein assay for determination of expression, activity, and inhibition of P-glycoprotein. The studied compounds significantly and concentration-dependently increased PXR activity in the ABCB1-driven luciferase-based reporter gene assay. We observed much stronger induction of ABCB1 mRNA by S-tamsulosin as compared to the R or racemic form. R or racemic form of tolterodine and R-tamsulosin concentration-dependently increased P-gp protein expression; the latter also enhanced P-gp efflux function in a rhodamine-based efflux assay. R-tamsulosin and all forms of tolderodine slightly inhibited P-gp. The effect on CYP3A4 expression followed the same pattern but was much weaker. Taken together, tamsulosin and tolterodine are demonstrated to interfere with P-gp and CYP3A4 regulation in an enantiomer-specific way.

Graphene Quantum Dots-Capped Magnetic Mesoporous Silica Nanoparticles as a Multifunctional Platform for Controlled Drug Delivery, Magnetic Hyperthermia, and Photothermal Therapy

A multifunctional platform is reported for synergistic therapy with controlled drug release, magnetic hyperthermia, and photothermal therapy, which is composed of graphene quantum dots (GQDs) as caps and local photothermal generators and magnetic mesoporous silica nanoparticles (MMSN) as drug carriers and magnetic thermoseeds. The structure, drug release behavior, magnetic hyperthermia capacity, photothermal effect, and synergistic therapeutic efficiency of the MMSN/GQDs nanoparticles are investigated. The results show that monodisperse MMSN/GQDs nanoparticles with the particle size of 100 nm can load doxorubicin (DOX) and trigger DOX release by low pH environment. Furthermore, the MMSN/GQDs nanoparticles can efficiently generate heat to the hyperthermia temperature under an alternating magnetic field or by near infrared irradiation. More importantly, breast cancer 4T1 cells as a model cellular system, the results indicate that compared with chemotherapy, magnetic hyperthermia or photothermal therapy alone, the combined chemo-magnetic hyperthermia therapy or chemo-photothermal therapy with the DOX-loaded MMSN/GQDs nanosystem exhibits a significant synergistic effect, resulting in a higher efficacy to kill cancer cells. Therefore, the MMSN/GQDs multifunctional platform has great potential in cancer therapy for enhancing the therapeutic efficiency.

Myeloid cells are required for PD-1/PD-L1 checkpoint activation and the establishment of an immunosuppressive environment in pancreatic cancer

BACKGROUND

Pancreatic cancer is characterised by the accumulation of a fibro-inflammatory stroma. Within this stromal reaction, myeloid cells are a predominant population. Distinct myeloid subsets have been correlated with tumour promotion and unmasking of anti-tumour immunity.

OBJECTIVE

The goal of this study was to determine the effect of myeloid cell depletion on the onset and progression of pancreatic cancer and to understand the relationship between myeloid cells and T cell-mediated immunity within the pancreatic cancer microenvironment.

METHODS

Primary mouse pancreatic cancer cells were transplanted into CD11b-diphtheria toxin receptor (DTR) mice. Alternatively, the iKras* mouse model of pancreatic cancer was crossed into CD11b-DTR mice. CD11b+ cells (mostly myeloid cell population) were depleted by diphtheria toxin treatment during tumour initiation or in established tumours.

RESULTS

Depletion of myeloid cells prevented KrasG12D-driven pancreatic cancer initiation. In pre-established tumours, myeloid cell depletion arrested tumour growth and in some cases, induced tumour regressions that were dependent on CD8+ T cells. We found that myeloid cells inhibited CD8+ T-cell anti-tumour activity by inducing the expression of programmed cell death-ligand 1 (PD-L1) in tumour cells in an epidermal growth factor receptor (EGFR)/mitogen-activated protein kinases (MAPK)-dependent manner.

CONCLUSION

Our results show that myeloid cells support immune evasion in pancreatic cancer through EGFR/MAPK-dependent regulation of PD-L1 expression on tumour cells. Derailing this crosstalk between myeloid cells and tumour cells is sufficient to restore anti-tumour immunity mediated by CD8+ T cells, a finding with implications for the design of immune therapies for pancreatic cancer.