Beyond Herceptin and Gleevec

Real-World Experiences of Next-Generation Sequencing in Oncology: From an Indian Multicenter Registry and Collaborative Centers

Background The integration of next-generation sequencing (NGS) in guiding personalized therapy for oncology faces the challenges, primarily, of cost and drug accessibility. Limited data from Indian academic centers accentuate the need for comprehensive insights into the real-world applications of NGS in oncology.

Methods The Network of Oncology Clinical Trials in India (NOCI), accessible at www.noci-india.com, compiled data on patients who underwent NGS for solid organ cancers from January 1, 2018, to December 31, 2021. This study aimed to elucidate the testing indications, sample types analyzed, and the resultant impact on patient care.

Results Analysis of data from six centers included 278 subjects, with 24 specimens (9%) excluded due to quality test failure. Tissue constituted 59.7% of specimens, blood 38.5%, and both 1.8%. Predominantly, NGS was employed for identifying BRCA1/2 mutations (56%) and for targeted therapy in non-small-cell lung cancer (NSCLC; 28%). Only 41 (16%) patients with other cancers underwent multigene NGS panels in pursuit of targetable mutations. Among them, 13 exhibited targetable mutations, and 3 received treatment based on NGS findings.

Conclusion This study underscores that the majority of NGS applications focused on screening for BRCA1/2 mutations and identifying targetable mutations in NSCLC. However, among those undergoing NGS for advanced cancers, only a limited number received personalized therapy. The findings underscore the challenges of utilizing NGS in off-label indications within resource-constrained settings.

Inhibition of Soluble Stem Cell Factor Promotes Intestinal Mucosal Repair

BACKGROUND

Incidences of inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, are escalating worldwide and can be considered a global public health problem. Given that the gold standard approach to IBD therapeutics focuses on reducing the severity of symptoms, there is an urgent unmet need to develop alternative therapies that halt not only inflammatory processes but also promote mucosal repair. Previous studies have identified increased stem cell factor (SCF) expression in inflamed intestinal mucosal tissues. However, the role that SCF plays in mediating intestinal inflammation and repair has not been explored.

METHODS

Changes in the expression of SCF were evaluated in the colonic tissue of healthy mice and during dextran sodium sulfate (DSS)-induced colitis. Furthermore, mucosal wound healing and colitis severity were analyzed in mice subjected to either mechanical biopsy or DSS treatment, respectively, following intestinal epithelial cell-specific deletion of SCF or anti-SCF antibody administration.

RESULTS

We report robust expression of SCF by intestinal epithelial cells during intestinal homeostasis with a switch to immune cell-produced SCF during colitis. Data from mice with intestinal epithelial cell-specific deletion of SCF highlight the importance of immune cell-produced SCF in driving the pathogenesis of colitis. Importantly, antibody-mediated neutralization of total SCF or the specific SCF248 isoform decreased immune cell infiltration and enhanced mucosal wound repair following biopsy-induced colonic injury or DSS-induced colitis.

CONCLUSIONS

These data demonstrate that SCF functions as a pro-inflammatory mediator in mucosal tissues and that specific neutralization of SCF248 could be a viable therapeutic option to reduce intestinal inflammation and promote mucosal wound repair in individuals with IBD.

Phosphorylation: A Fast Switch For Checkpoint Signaling

Checkpoint signaling involves a variety of upstream and downstream factors that participate in the regulation of checkpoint expression, activation, and degradation. During the process, phosphorylation plays a critical role. Phosphorylation is one of the most well-documented post-translational modifications of proteins. Of note, the importance of phosphorylation has been emphasized in aspects of cell activities, including proliferation, metabolism, and differentiation. Here we summarize how phosphorylation of specific molecules affects the immune activities with preference in tumor immunity. Of course, immune checkpoints are given extra attention in this book. There are many common pathways that are involved in signaling of different checkpoints. Some of them are integrated and presented as common activities in the early part of this chapter, especially those associated with PD-1/PD-L1 and CTLA-4, because investigations concerning them are particularly abundant and variant. Their distinct regulation is supplementarily discussed in their respective section. As for checkpoints that are so far not well explored, their related phosphorylation modulations are listed separately in the later part. We hope to provide a clear and systematic view of the phosphorylation-modulated immune signaling.

Trastuzumab-Coated Nanoparticles Loaded With Docetaxel for Breast Cancer Therapy

Docetaxel (DTX) is commonly used for breast cancer treatment. Tween 80 used for DTX dissolution in its clinical formulation causes severe hypersensitivity and other adverse reactions. In this study, trastuzumab (Tmab)-coated lipid-polymer hybrid nanoparticles (PLNs) were prepared, composed of poly (d, l-lactide-co-glycolide), PLGA; polyethylenimine (PEI); and lipids. The PLGA/PEI/lipid formed a hydrophobic core, while Tmab was electrostatically adsorbed on the surface of the PLNs as a ligand that targets human epidermal growth factor receptor 2 (HER2)-positive breast cancer cells. The resulting PLNs, electrostatically adsorbed Tmab-bearing PLGA/PEI/lipid nanoparticles (eTmab-PPLNs), had a mean particle size of 217.4 ± 13.36 nm, a ζ potential of 0.056 ± 0.315 mV, and good stability. In vitro, the eTmab-PPLNs showed increased cytotoxicity in HER2-postive BT474 cells but not in HER2-negative MCF7 cells. Studies of the ability of eTmab-PPLNs to target HER2 were performed. The uptake of eTmab-PPLNs was shown to be dependent on HER2 expression level. Therefore, eTmab-PPLNs provide a promising therapeutic for the treatment of breast cancer.

Ginsenoside Rg3: Potential Molecular Targets and Therapeutic Indication in Metastatic Breast Cancer

Breast cancer is still one of the most prevalent cancers and a leading cause of cancer death worldwide. The key challenge with cancer treatment is the choice of the best therapeutic agents with the least possible toxicities on the patient. Recently, attention has been drawn to herbal compounds, in particular ginsenosides, extracted from the root of the Ginseng plant. In various studies, significant anti-cancer properties of ginsenosides have been reported in different cancers. The mode of action of ginsenoside Rg3 (Rg3) in in vitro and in vivo breast cancer models and its value as an anti-cancer treatment for breast cancer will be reviewed.

Complexity of genome sequencing and reporting: Next generation sequencing (NGS) technologies and implementation of precision medicine in real life

The finalization of the Human Genome Project in 2003 paved the way for a deeper understanding of cancer, favouring a faster progression towards "personalized" medicine. Research in oncology has progressively focused on the sequencing of cancer genomes, to better understand the genetic basis of tumorigenesis and identify actionable alterations to guide cancer therapy. Thanks to the development of next-generation-sequencing (NGS) techniques, sequencing of tumoral DNA is today technically easier, faster and cheaper. Commercially available NGS panels enable the detection of single or global genomic alterations, namely gene mutation and mutagenic burden, both on germline and somatic DNA, potentially predicting the response or resistance to cancer treatments. Profiling of tumor DNA is nowadays a standard in cancer research and treatment. In this review we discuss the history, techniques and applications of NGS in cancer care, under a "personalized tailored therapy" perspective.

Phosphorylation: Implications in Cancer

Post translational modifications (PTMs) are involved in variety of cellular activities and phosphorylation is one of the most extensively studied PTM, which regulates a number of cellular functions like cell growth, differentiation, apoptosis and cell signaling in healthy condition. However, alterations in phosphorylation pathways result in serious outcomes in the form of diseases, especially cancer. Many signalling pathways including Tyrosine kinase, MAP kinase, Cadherin-catenin complex, Cyclin-dependent kinase etc. are major players of the cell cycle and deregulation in their phosphorylation-dephosphorylation cascade has been shown to be manifested in the form of various types of cancers. Tyrosine kinase family encompasses the greatest number of oncoproteins. MAPK cascade has an importance role in cancer growth and progression. Bcl-2 family proteins serve either proapoptotic or antiapoptotic function. Cadherin-catenin complex regulates cell adhesion properties and cyclins are the key regulators of cell cycle. Altered phosphorylations in any of the above pathways are strongly associated with cancer, at the same time they serve as the potential tergets for drug development against cancer. Drugs targeting tyrosine kinase are potent anticancer drugs. Inhibitors of MEK, PI3K and ERK signalling pathways are undergoing clinical trials. Thus, drugs targeting phosphorylation pathways represent a promising area for cancer therapy.

FOXM1 (Forkhead box M1) in tumorigenesis: overexpression in human cancer, implication in tumorigenesis, oncogenic functions, tumor-suppressive properties, and target of anticancer therapy

FOXM1 (Forkhead box M1) is a typical proliferation-associated transcription factor and is also intimately involved in tumorigenesis. FOXM1 stimulates cell proliferation and cell cycle progression by promoting the entry into S-phase and M-phase. Additionally, FOXM1 is required for proper execution of mitosis. In accordance with its role in stimulation of cell proliferation, FOXM1 exhibits a proliferation-specific expression pattern and its expression is regulated by proliferation and anti-proliferation signals as well as by proto-oncoproteins and tumor suppressors. Since these factors are often mutated, overexpressed, or lost in human cancer, the normal control of the foxm1 expression by them provides the basis for deregulated FOXM1 expression in tumors. Accordingly, FOXM1 is overexpressed in many types of human cancer. FOXM1 is intimately involved in tumorigenesis, because it contributes to oncogenic transformation and participates in tumor initiation, growth, and progression, including positive effects on angiogenesis, migration, invasion, epithelial-mesenchymal transition, metastasis, recruitment of tumor-associated macrophages, tumor-associated lung inflammation, self-renewal capacity of cancer cells, prevention of premature cellular senescence, and chemotherapeutic drug resistance. However, in the context of urethane-induced lung tumorigenesis, FOXM1 has an unexpected tumor suppressor role in endothelial cells because it limits pulmonary inflammation and canonical Wnt signaling in epithelial lung cells, thereby restricting carcinogenesis. Accordingly, FOXM1 plays a role in homologous recombination repair of DNA double-strand breaks and maintenance of genomic stability, that is, prevention of polyploidy and aneuploidy. The implication of FOXM1 in tumorigenesis makes it an attractive target for anticancer therapy, and several antitumor drugs have been reported to decrease FOXM1 expression.

Platinum resistance in breast and ovarian cancer cell lines

Breast and ovarian cancers are among the 10 leading cancer types in females with mortalities of 15% and 6%, respectively. Despite tremendous efforts to conquer malignant diseases, the war on cancer declared by Richard Nixon four decades ago seems to be lost. Approximately 21,800 women in the US will be diagnosed with ovarian cancer in 2011. Therefore, its incidence is relatively low compared to breast cancer with 207.090 prognosed cases in 2011. However, overall survival unmasks ovarian cancer as the most deadly gynecological neoplasia. Platinum-based chemotherapy is emerging as an upcoming treatment modality especially in triple negative breast cancer. However, in ovarian cancer Platinum-complexes for a long time are established as first line treatment. Emergence of a resistant phenotype is a major hurdle in curative cancer therapy approaches and many scientists around the world are focussing on this issue. This review covers new findings in this field during the past decade.

Epidermal growth factor and estrogen act by independent pathways to additively promote the release of the angiogenic chemokine CXCL8 by breast tumor cells

The tumor microenvironment contains multiple cancer-supporting factors, whose joint activities promote malignancy. Here, we show that epidermal growth factor (EGF) and estrogen upregulate in an additive manner the transcription and the secretion of the angiogenic chemokine CXCL8 (interleukin 8 [IL-8]) in breast tumor cells. In view of published findings on cross-regulatory interactions between EGF receptors and estrogen receptors in breast tumor cells, we asked whether the additive effects of EGF and estrogen were due to their ability to (1) induce intracellular cross talk and amplify shared regulatory pathways or (2) act in independent mechanisms, which complement each other. We found that stimulation by EGF alone induced the release of CXCL8 through signaling pathways involving ErbB2, ErbB1, Erk, and phosphoinositide 3-kinase (PI3K). ErbB2 and Erk were also involved in estrogen activities on CXCL8 but to a lower extent than with EGF. However, in the joint stimulatory setup, the addition of estrogen to EGF has led to partial (ErbB2, ErbB1, Erk) or complete (PI3K) shutoff of the involvement of these activation pathways in CXCL8 up-regulation. Furthermore, when costimulation by EGF + estrogen was applied, the effects of estrogen were channeled to regulation of CXCL8 at the transcription level, acting through the transcription factor estrogen receptor α (ERα). In parallel, in the joint stimulation, EGF acted independently at the transcription level through AP-1, to upregulate CXCL8 expression. The independent activities of EGF and estrogen on CXCL8 transcription reinforce the need to introduce simultaneous targeting of ErbBs and ERα to achieve effective therapy in breast cancer.

Phosphorylation State-Dependent High Throughput Screening of the c-Met Kinase

High-throughput screening (HTS) of ~50,000 chemical compounds against phosphorylated and unphosphorylated c-Met, a tyrosine kinase receptor for hepatocyte growth factor (HGF), was carried out in order to compare hit rates, hit potencies and also to explore scaffolds that might serve as potential leads targeting only the unphosphorylated form of the enzyme. The hit rate and potency for the confirmed hit molecules were higher for the unphosphoryalted form of c-Met. While the target of small molecule inhibitor discovery efforts has traditionally been the phosphorylated form, there are now examples of small molecules that target unphosphorylated kinases. Screening for inhibitors of unphosphorylated kinases may represent a complementary approach for prioritizing chemical scaffolds for hit-to-lead follow ups.

Potential therapeutic effect of glycogen synthase kinase 3beta inhibition against human glioblastoma

PURPOSE

Glioblastoma represents the malignant brain tumor that is most refractory to treatment and in which the identification of molecular target(s) is urgently required. We investigated the expression, activity, and putative pathologic role of glycogen synthase kinase 3beta (GSK3beta), an emerging therapeutic target for neurodegenerative diseases, in human glioblastoma.

EXPERIMENTAL DESIGN

The active fraction of GSK3beta that is phosphorylated at the tyrosine 216 residue (pGSK3betaY216) was identified in glioblastoma cell lines. GSK3beta activity for phosphorylating its substrate was detected in these cells by nonradioisotopic in vitro kinase assay.

RESULTS

Higher expression levels of GSK3beta and pGSK3betaY216 were frequently detected in glioblastomas compared with nonneoplastic brain tissues. Inhibition of GSK3beta activity by escalating doses of a small-molecule inhibitor (AR-A014418) or inhibition of its expression by RNA interference induced the apoptosis and attenuated the survival and proliferation of glioblastoma cells in vitro. Inhibition of GSK3beta was associated with increased expression of p53 and p21 in glioblastoma cells with wild-type p53 and with decreased Rb phosphorylation and expression of cyclin-dependent kinase 6 in all glioblastoma cell lines. Administration of AR-A014418 at a low dose significantly sensitized glioblastoma cells to temozolomide and 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea, chemotherapeutic agents used in the clinical setting, as well as to ionizing radiation.

CONCLUSION

These results indicate that GSK3beta exerts a pathologic role by promoting the survival and proliferation of glioblastoma cells and by protecting them from apoptosis via the inactivation of p53- and/or Rb-mediated pathways. Consequently, we propose that GSK3beta provides a potential therapeutic target in glioblastoma.

Quantitative phosphoproteomics--an emerging key technology in signal-transduction research

Protein phosphorylation is the most important type of reversible post-translational modification involved in the regulation of cellular signal-transduction processes. In addition to controlling normal cellular physiology on the molecular level, perturbations of phosphorylation-based signaling networks and cascades have been implicated in the onset and progression of various human diseases. Recent advances in mass spectrometry-based proteomics helped to overcome many of the previous limitations in protein phosphorylation analysis. Improved isotope labeling and phosphopeptide enrichment strategies in conjunction with more powerful mass spectrometers and advances in data analysis have been integrated in highly efficient phosphoproteomics workflows, which are capable of monitoring up to several thousands of site-specific phosphorylation events within one large-scale analysis. Combined with ongoing efforts to define kinase-substrate relationships in intact cells, these major achievements have considerable potential to assess phosphorylation-based signaling networks on a system-wide scale. Here, we provide an overview of these exciting developments and their potential to transform signal-transduction research into a technology-driven, high-throughput science.

Focal adhesion components are essential for mammalian cell cytokinesis

The final stages in mammalian cytokinesis are poorly understood. Previously, we reported that the ADP-ribosyltransferase activity of Pseudomonas aeruginosa type III secreted toxin ExoT inhibits late stages of cytokinesis. Given that Crk adaptor proteins are the major substrates of ExoT ADP-ribosyltransferase activity, we tested the involvement of Crk in cytokinesis. We report that the focal adhesion-associated proteins, Crk and paxillin are essential for completion of cytokinesis. When their function is absent, the cytoplasmic bridge fails to resolve and the daughter cells fuse to form a binucleated cell. During cytokinesis, Crk is required for syntaxin-2 recruitment to the midbody, while paxillin is required for both Crk and syntaxin-2 localization to this compartment. Our data demonstrate that the subcellular localization and the activity of RhoA and citron K, which are essential for early stages of cytokinesis, are not dependent on paxillin, Crk or syntaxin-2. These studies reveal a novel role for Crk and paxillin in cytokinesis and suggest that focal adhesion complex, as a unit, may partake in this fundamental cellular process.

Naturally occurring homoisoflavonoids function as potent protein tyrosine kinase inhibitors by c-Src-based high-throughput screening

Protein tyrosine kinase (PTK) inhibitors represent emerging therapeutics for cancer chemoprevention. In our study, hematoxylin (26) was identified as one of the most remarkable c-Src inhibitors in an orthogonal compound-mixing library (32200 compounds) by using an ELISA-based automated high-throughput screening (HTS) strategy. Interestingly, hematoxylin was found to be an ATP competitive broad-spectrum PTK inhibitor in vitro, with IC50 values ranging from nanomolar to micromolar level. Further studies showed that such inhibition was associated with the PTK phosphorylation and subsequent downstream signaling pathways. The structure-activity relationship assessment of the PTK inhibitory potency of hematoxylin analogues isolated from Heamatoxylon campechianum was in good agreement with the result of concurrent molecular docking simulation: the catechol moiety in ring A and the hematoxylin-like three-dimensional structure were essential for c-Src-targeted activities. Hematoxylin and its natural analogues were substantially validated to function as a new class of PTK inhibitors.

Trastuzumab therapy vs tetracycline controlled ERBB2 downregulation: influence on tumour development in an ERBB2-dependent mouse tumour model

Trastuzumab (Herceptin) has improved therapy of breast cancer. Only patients overexpressing ERBB2 are treated with trastuzumab, whereas its use in tumours without ERBB2 expression is useless. This led to the concept that the subgroup of trastuzumab-sensitive tumours is ‘ERBB2-dependent’, meaning that ERBB2 signalling is indispensable for growth of these tumours. We used a mouse model that allows anhydrotetracycline (ATc)-controlled downregulation of ERBB2 in tumour tissue. ERBB2 mRNA and protein expression were downregulated below detection limit leading to a macroscopically complete tumour remission within 14 days. Tumour remission was accompanied by a strong decrease in proliferation, a moderate increase in apoptosis, as well as dephosphorylation of ERK1/2 and AKT/PKB. These data clearly indicate ERBB2 dependence. Therefore, a high sensitivity to trastuzumab may be suspected. Surprisingly, trastuzumab caused a much weaker effect compared to ATc-induced ERBB2 downregulation, although a decrease in ERBB2 membrane localisation was induced. Only a slight decrease in proliferation and a weak transient increase in apoptosis were observed. Interestingly, tumours responded to trastuzumab by a sharp fivefold increase in phosphorylated AKT/PKB as well as a 3.5- and 5.3-fold increase in AKT1 and AKT2 mRNA levels, respectively. In conclusion, ‘ERBB2 dependence’ is not sufficient to define trastuzumab-responsive tumours. The suboptimal effect of trastuzumab compared to the maximally possible effect induced by ATc demonstrates a high potential for improved ERBB2 blocking therapies.

Effect of deleterious nsSNP on the HER2 receptor based on stability and binding affinity with herceptin: a computational approach

In this study, we identified the most deleterious non-synonymous SNP of ERBB2 (HER2) receptors by its stability and investigated its binding affinity with herceptin. Out of 135 SNPs, 10 are nsSNPs in the coding region, in which one of the nsSNP (SNPid rs4252633) is commonly found to be damaged by I-Mutant 2.0, SIFT and PolyPhen servers. With this effort, we modelled the mutant HER2 protein based on this deleterious nsSNP (rs4252633). The modeled mutant showed less stability than native HER 2 protein, based on both total energy of the mutant and stabilizing residues in the mutant protein. This is due to a deviation between the mutant and the native HER2, having an RMSD of about 2.81 A. Furthermore, we compared the binding efficiency of herceptin with native and mutant HER2 receptors. We found that herceptin has a high binding affinity with mutant HER2 receptor, with a binding energy of -24.40 kcal/mol, as compared to the native type, which has a binding energy of -15.26 kcal/mol due to six-hydrogen bonding and two salt bridges exist between herceptin and the mutant type, whereas the native type establishes four hydrogen bonds and two salt bridges with herceptin. This analysis portrays that mutant type has two additional hydrogen bonds with herceptin compared with the native type. Normal mode analysis also showed that the two amino acids, namely Asp596 and Glu598 of mutant HER2, forming additional hydrogen bonding with herceptin, had a slightly higher flexibility than the native type. Based on our investigations, we propose that SNPid rs4252633 could be the most deleterious nsSNP for HER2 receptor, and that herceptin could be the best drug for mutant compared to the native HER2 target.

Rational design of competitive prolactin/growth hormone receptor antagonists

There is increasing evidence that prolactin (PRL) and growth hormone (GH) act as growth-promoters of breast tumors. Recent arguments have accumulated to suggest that when they are locally-produced within the mammary tissue, these hormones, acting by an autocrine-paracrine mechanism may have enhanced, or even specific functions compared to endocrine PRL and GH. Classical drugs blocking pituitary hormone production (dopamine and somatostatin analogs) are ineffective on extrapituitary expression of PRL/GH genes, therefore the undesirable effects of these locally-produced hormones remain a target of interest for alternative strategies. This has encouraged the development of competitive PRL and/or GH receptor antagonists, which involve engineered variants of natural receptor ligands (PRL or GH) aimed at blocking receptor activation rather than hormone production in peripheral tissues. This article overviews the rational design of this new class of molecules, their specific molecular features (receptor specificity, biological properties, etc.) and whenever available, the data that have been obtained in cell or animal models of breast cancer.

Multiparameter noninvasive assessment of treatment susceptibility, drug target inhibition and tumor response guides cancer treatment

New cancer therapies are increasingly molecular-pathway specific. The evaluation of these novel therapies would be greatly facilitated by the development of noninvasive methods to assess multiple tumor cellular and molecular parameters. Using fluorescent probes specific for HER2/neu (AF750-trastuzumab) and apoptosis (Cy5.5-Annexin), we demonstrate a multichannel near infrared molecular imaging approach that yields accurate and early assessment of treatment susceptibility, drug target inhibition and tumor response during HER2-targeted therapy of orthotopic human mammary carcinomas in mice with trastuzumab (Herceptin). This combined approach detects both partial treatment response (tumor growth inhibition without regression) as well as therapeutic resistance before alterations in tumor growth are apparent. Partially responsive tumors exhibit increased Annexin signal when trastuzumab is combined with a cytotoxic agent (paclitaxel), which predicts subsequent tumor regression and suggests that imaging can guide therapy optimization. This multiparametric imaging approach has great potential in the clinical setting for determining patient eligibility, adequate drug dosing and early biological response of molecularly-targeted cancer therapies.

The cancer cell's "power plants" as promising therapeutic targets: an overview

This introductory article to the review series entitled "The Cancer Cell's Power Plants as Promising Therapeutic Targets" is written while more than 20 million people suffer from cancer. It summarizes strategies to destroy or prevent cancers by targeting their energy production factories, i.e., "power plants." All nucleated animal/human cells have two types of power plants, i.e., systems that make the "high energy" compound ATP from ADP and P( i ). One type is "glycolysis," the other the "mitochondria." In contrast to most normal cells where the mitochondria are the major ATP producers (>90%) in fueling growth, human cancers detected via Positron Emission Tomography (PET) rely on both types of power plants. In such cancers, glycolysis may contribute nearly half the ATP even in the presence of oxygen ("Warburg effect"). Based solely on cell energetics, this presents a challenge to identify curative agents that destroy only cancer cells as they must destroy both of their power plants causing "necrotic cell death" and leave normal cells alone. One such agent, 3-bromopyruvate (3-BrPA), a lactic acid analog, has been shown to inhibit both glycolytic and mitochondrial ATP production in rapidly growing cancers (Ko et al., Cancer Letts., 173, 83-91, 2001), leave normal cells alone, and eradicate advanced cancers (19 of 19) in a rodent model (Ko et al., Biochem. Biophys. Res. Commun., 324, 269-275, 2004). A second approach is to induce only cancer cells to undergo "apoptotic cell death." Here, mitochondria release cell death inducing factors (e.g., cytochrome c). In a third approach, cancer cells are induced to die by both apoptotic and necrotic events. In summary, much effort is being focused on identifying agents that induce "necrotic," "apoptotic" or apoptotic plus necrotic cell death only in cancer cells. Regardless how death is inflicted, every cancer cell must die, be it fast or slow.

Inhibition of GSK-3 beta activity attenuates proliferation of human colon cancer cells in rodents

The authors' recent discovery that glycogen synthase kinase-3beta (GSK-3beta) participates in colon cancer cells' survival and proliferation prompted us to investigate whether GSK-3beta inhibition alters proliferation of colon cancer cells in vivo. Groups of four or five athymic mice (Balb/c, nu/nu) with subcutaneous xenografts of SW480 human colon cancer cells were treated with dimethyl sulfoxide (DMSO) or different doses (1, 2 and 5 mg/kg body weight) of either small-molecule GSK-3beta inhibitor (SB-216763 and AR-A014418) by intraperitoneal injection three times per week for 5 weeks. Compared with DMSO (a diluent of the GSK-3beta inhibitors) as a control, either GSK-3beta inhibitor significantly inhibited proliferation of cancer cell xenografts in the rodents in a dose-dependent manner. Histochemical and immunohistochemical analysis of tumor xenografts demonstrated a significant, dose-dependent decrease in fractions of proliferating cells and an increase in the incidence of apoptosis of cancer cells in mice treated with either GSK-3beta inhibitor. No adverse events or effects were observed in the rodents during the course of treatment, except for rare lethal accidents due to intraperitoneal injection. Morphological examination showed no apparent pathologic changes in major organs including the lungs, liver, pancreas, kidneys, spleen and large bowel of rodents treated with DMSO and the GSK-3beta inhibitors. The results indicate that the GSK-3beta inhibitors would be a novel class of therapeutic agent for colon cancer.

Clinical Translation of Genotyping and Haplotyping Data

The completion of the Human Genome Project has raised expectations for the translation of genomic knowledge into clinical forms that would lead to improved diagnosis of diseases and identification of new drug targets. Such an opportunity is quite challenging within science and society, although there is still uncertainty regarding its outcomes in new drug development and healthcare. Undoubtedly, however, the recent approval by the US FDA of the first two pharmacogenomic tests for genotyping drug-metabolising enzymes is expected to empower and eventually lead to general applicability of various genetic diagnostic tools to improve pharmacotherapy outcomes in the post-genomic era. To this end, the application of genomic knowledge and technologies in everyday clinical practice leads personalised medicine concepts towards the achievement of individualised drug selection and dosage profiling (i.e. pharmacotyping) for ensuring maximum drug effectiveness and safety. Within this framework, pharmacogenomic information can implement the existing clinical pharmacology experience in clinical diagnosis and drug delivery. The latter can be further advanced through the development of workflow information-based operating systems in healthcare to support the utilisation, assessment and outcome of engaged clinical and genomic information. Such a direction may help to suitably revise and adjust clinical regulatory guidelines as well as clinical pharmacology guidelines. This will further facilitate better designing of clinical trials for new drug development as well as pharmacovigilance registries and evaluation of these data. To critically describe the existing environment, this article comprehensively discusses scientific efforts aimed at making clinical translation of genotyping and haplotyping data more efficient and productive in forms that are readily applicable in everyday healthcare. In addition, specific and systematic pharmacogenomic and clinical attempts related to the development of new molecularly targeted drugs, as well as improvement of the efficacy and safety of commonly prescribed drugs, are presented. To this end, the clinical pharmacogenomic experience gained thus far in the use of tyrosine kinase inhibitors in oncology, as well as the process of empowerment through the use of genomic knowledge of the cardiac safety of drugs modulating the function of the human ether-à-go-go-related gene (HERG) potassium channel, represent examples of how the implementation of clinical experience with genomic information guides the development of new drugs and the improvement of pharmacotherapy outcomes.

Insulin growth factor-I and epidermal growth factor receptors recruit distinct upstream signaling molecules to enhance AKT activation in mammary epithelial cells

IGF-I and epidermal growth factor (EGF) stimulate both normal mammary epithelial cell (MEC) growth and tumorigenesis. Whereas both growth factors increase DNA synthesis in MECs, how they evoke a greater response in combination when they activate similar signaling pathways remains unknown. In the present study, we investigated the signaling pathways by which these mitogens act in concert to increase DNA synthesis. Only EGF activated the MAPK pathway, and no further increase in MAPK activation was observed when both mitogens were added together. Both growth factors activated the phosphatidylinositol-3 kinase pathway, and simultaneous treatment enhanced phosphorylation of both AKT and its downstream target, p70S6K. The enhanced activation of AKT was observed at multiple time points (5 and 15 min) and growth factor concentrations (2.5-100 ng/ml). IGF-I activated AKT via insulin receptor substrate-1 and p85, the regulatory subunit of phosphatidylinositol-3 kinase. Treatment with EGF had no effect on insulin receptor substrate-1; however, it activated the EGF receptor, SHC, and c-Src. EGF treatment caused the association of SHC with Grb2 and Gab2 with phospho-SHC, phospho-Gab1, Grb2, and p85. Interestingly, inhibition of Src activation blocked the ability of EGF, but not IGF-I, to activate AKT. This corresponded with a decrease in phosphorylation of the EGF receptor and its association with phospho-SHC as well as downstream signaling. Unexpectedly, inhibition of Src increased basal MAPK activation. This is the first study to show that EGF and IGF-I use separate upstream components within a given MEC line to enhance AKT phosphorylation, contributing to increased DNA synthesis.

Effects of the potential chemopreventive agent DMU-135 on adenoma development in the ApcMin+ mouse

DMU-135 (3,4-Methylenedioxy-3',4',5'-trimethoxy chalcone) is a novel anticancer prodrug designed to be activated into a potent tyrosine kinase inhibitor by the tumour selective enzyme activity of the cytochrome P450 enzyme CYP1B1. CYP1B1 is selectively expressed in a wide variety of tumours including colon. The hypothesis was tested that DMU-135 would inhibit Apc(Min/+) mouse gastrointestinal adenoma formation. From 4-18 weeks of age animals received DMU-135 (0.2% w:w) in AIN93G diet. DMU-135 was well tolerated, induced no systemic side-effects and reduced adenoma multiplicity by 46 +/- 18.3% compared to controls (p < 0.001). Further characterisation of this promising chemopreventive agent is required.

Mechanisms of Disease: cancer targeting and the impact of oncogenic RET for medullary thyroid carcinoma therapy

Growing evidence supports the concept of oncogene dependence for cancer development; inhibition of the initiating oncogene can result in revertion of the neoplastic phenotype. The outstanding role of the RET proto-oncogene in the development of medullary thyroid carcinoma (MTC) is well established. With the emerging knowledge concerning the signal transduction pathways leading to subsequent neoplastic transformation, oncogenic activated RET becomes a highly attractive target for selective cancer therapy. A variety of novel approaches that target RET directly or indirectly have recently emerged and an increasing number are currently being assessed in clinical trials. In view of these findings, it becomes strikingly obvious that inhibition of RET oncogene function can be a viable option for the treatment of MTC. We summarize the current evidence for RET involvement in the etiology of MTC, and the therapeutic targeting of this process in preclinical and clinical studies.

Antibodies for angiogenesis inhibition, vascular targeting and endothelial cell transcytosis

The endothelium is increasingly recognized as a target for biomedical intervention, not only for its accessibility to molecular agents coming from the blood-stream, but also for the active role played by endothelial cell proliferation to support diseases such as cancer, blinding ocular disorders and chronic inflammatory conditions. The notion that solid tumors cannot grow beyond a size of few millimeters without inducing the proliferation of new blood vessels has stimulated the search for mediators of angiogenesis and for inhibitors of this process, culminating in the approval of a humanized monoclonal antibody to VEGF-A for oncology applications. In parallel, researchers have begun to consider imaging and therapeutic strategies based on the selective delivery of bioactive agents to the new blood vessels, mediated by monoclonal antibody derivatives. Recently, the field of vascular targeting research has been extended to the investigation of molecular agents that may mediate endothelial cell transcytosis, in the hope to overcome this body barrier for drug delivery. This article reviews some of the most significant advances in these areas, and outlines future challenges and opportunities.

A parallel-gradient microfluidic chamber for quantitative analysis of breast cancer cell chemotaxis

Growth factor-induced chemotaxis of cancer cells is believed to play a critical role in metastasis, directing the spread of cancer from the primary tumor to secondary sites in the body. Understanding the mechanistic and quantitative behavior of cancer cell migration in growth factor gradients would greatly help in future treatment of metastatic cancers. Using a novel microfluidic chemotaxis chamber capable of simultaneously generating multiple growth factor gradients, we examined the migration of the human metastatic breast cancer cell line MDA-MB-231 in various conditions. First, we quantified and compared the migration in two gradients of epidermal growth factor (EGF) spanning different concentrations: 0-50 ng/ml and 0.1-6 ng/ml. Cells showed a stronger response in the 0-50 ng/ml gradient. However, the fact that even a shallow gradient of EGF can induce chemotaxis, and that EGF can direct migration over a large dynamic range of gradients, confirms the potency of EGF as a chemoattractant. Second, we investigated the effect of antibody against the EGF receptor (EGFR) on MDA-MB-231 chemotaxis. Quantitative analysis indicated that anti-EGFR antibody impaired both motility and directional orientation (CI = 0.03, speed = 0.71 microm/min), indicating that cell motility was induced by the activation of EGFR. The ability to compare, in terms of quantitative parameters, the effects of different pharmaceutical inhibitors, as well as subtle differences in experimental conditions, will aid in our understanding of mechanisms that drive metastasis. The microfluidic chamber described in this work will provide a platform for cell-based assays that can be used to compare the effectiveness of different pharmaceutical compounds targeting cell migration and metastasis.

Phosphoproteomics in analyzing signaling pathways

A surprisingly fewer than expected number of genes in the human genome suggests that sophistication of its biologic system is, in part, due to complex regulation of protein activities. The activities of most cellular proteins are regulated by post-translational modifications. One of the most important post-translational modifications is reversible protein phosphorylation, which decorates more than 30% of the proteome and regulates signal transduction pathways under normal conditions as well as in disorders such as diabetes, neurodegenerative diseases, autoimmune diseases and several forms of cancers. This review examines the recent developments in mass spectrometry-based methods for phosphoproteome analysis and its applications for the study of signal transduction pathways. The basic principles of non-mass spectrometry-based methods, such as chemical genetics and flow cytometry-based approaches, are also discussed as well as their specific advantages to signaling studies. Finally, signaling pathways are discussed in the light of large-scale protein interaction studies. The proteomic methods addressed in this review are emerging as some of the essential components in systems biology, which seeks to describe signaling networks through integration of diverse types of data and, in the future, to allow computational simulations of complex biologic pathways in health and disease.

Protein kinases and phosphatases as therapeutic targets in cancer

Protein phosphorylation plays key roles in many physiological processes and is often deregulated in pathological conditions. Our current understanding of how protein kinases and phosphatases orchestrate the phosphorylation changes that control cellular functions has made these enzymes potential drug targets for the treatment of many diseases. The success of the tyrosine kinase inhibitor Gleevec in the treatment of some cancers has further invigorated the development of kinase inhibitors as anti-cancer drugs. A large number of these compounds are currently undergoing clinical trials and there is much expectation on the therapeutic potential of these molecules, as more specific and less toxic drugs than currently used generic chemotherapeutic agents. In this manuscript, we review the current status of more than 30 protein kinase inhibitors with proven or potential therapeutic value for cancer treatment. These include inhibitors of receptor and cytosolic tyrosine kinases as well as compounds that target different families of serine/threonine kinases involved in signalling and cell cycle regulation. We also briefly touch on the prospects of phosphatase inhibitors. The combination of kinase inhibitors to target different components of signalling pathways that are found deregulated in tumours is also emerging as an interesting approach for cancer therapy.

Differentiation of human airway epithelia is dependent on erbB2

A clinical case documented a reversible change in airway epithelial differentiation that coincided with the initiation and discontinuation of trastuzumab, an anti-erbB2 antibody. This prompted the investigation into whether blocking the erbB2 receptor alters differentiation of the airway epithelium. To test this hypothesis, we treated an in vitro model of well-differentiated human airway epithelia with trastuzumab or heregulin-alpha, an erbB ligand. In addition, coculturing with human lung fibroblasts tested whether in vivo subepithelial fibroblasts function as an endogenous source of ligands able to activate erbB receptors expressed by the overlying epithelial cells. Epithelia were stained with hematoxylin and eosin and used for morphometric analysis. Trastuzumab treatment decreased the ciliated cell number by 49% and increased the metaplastic, flat cell number by 640%. Heregulin-alpha treatment increased epithelial height and decreased the number of metaplastic and nonciliated columnar cells, whereas it increased the goblet cell number. We found that normal human lung fibroblasts express transforming growth factor-alpha, heparin-binding epidermal-like growth factor, epiregulin, heregulin-alpha, and amphiregulin, all of which are erbB ligands. Cocultures of airway epithelia with primary fibroblasts increased epithelial height comparable to that achieved following heregulin-alpha treatment. These data show that erbB2 stimulation is required for maintaining epithelial differentiation. Furthermore, the mesenchyme underlying the airway epithelium secretes a variety of erbB ligands that may direct various pathways of epithelial differentiation.

Naphthofuroquinone derivatives: Inhibition of receptor tyrosine kinases

A series of dinaphtho[1,2-b;2',3'-d]furan-7,12-dione derivatives were synthesized and evaluated for inhibitory activities against receptor tyrosine kinases. The naphthofuroquinone compounds with dialkylaminoethoxy group at C(5)-position (7, 8, 10, and 11) manifested strong inhibitory activities against epidermal growth factor receptor and vascular endothelial growth factor receptor. Docking study of 11 with EGFR was also performed.

Information networks in the mammary gland

Unique developmental features during puberty, pregnancy, lactation and post-lactation make the mammary gland a prime object to explore genetic circuits that control the specification, proliferation, differentiation, survival and death of cells. Steroids and simple peptide hormones initiate and carry out complex developmental programmes, and reverse genetics has been used to define the underlying mechanistic connections.

Improving pharmacotherapy outcomes by pharmacogenomics: from expectation to reality?

The genomic era is now a reality and the extraction of genomic information with a practical value in healthcare represents the next challenge following the completion of the Human Genome Project. To this end, the first pharmacogenomics test approved by the US Food & Drug Administration for assessing cytochrome P450 (CYP)2D6 and CYP2C19 genotype in the implementation of pharmacotherapy decisions in patients, is expected to improve pharmaceutical care outcomes, at least for drugs that are substrates or inhibitors of these enzymes. Furthermore, the progress already achieved and the experience gained in the fields of pharmacogenomics and personalized medicine has clearly demonstrated that an interdisciplinary approach could better serve the target of improving pharmacotherapy outcomes in routine clinical practice. Such an approach will obviously move drug prescription towards pharmacotyping, a stage where the drug selection and dosage process carried out by medical practitioners for any given patient will be advanced by genomic knowledge and information.

Recent insights into the cell biology of bladder smooth muscle

Much of current biomedical research is focused on the development of 'targeted therapies' based on detailed knowledge about the signals that mediate aberrant cellular behavior in a given disease. Although this concept has been used most widely in cancer treatment, the same strategy applies to nonmalignant conditions such as pathologic tissue expansion in the genitourinary tract. A rigorous understanding of the key molecular events and pathways that underlie normal and pathologic activity of the bladder would allow us to identify potential targets for rational drug design. In this review, I will summarize our current understanding of cell signaling in bladder smooth muscle and highlight potential targets for drug-based treatment of tissue remodeling in the lower urinary tract.

Activation of p53-dependent apoptosis by acute ablation of glycogen synthase kinase-3beta in colorectal cancer cells

PURPOSE

The restoration of checkpoint mechanisms may provide a rational anticancer approach, but the molecular circuitries of how this can be achieved therapeutically are poorly understood. A pivotal signaling network in colorectal cancer cells involves glycogen synthase kinase-3beta (GSK3beta), a multifunctional kinase whose role in tumor cell survival is not defined.

EXPERIMENTAL DESIGN

We used molecular, genetic, and pharmacologic antagonists of GSK3beta in p53+/+ or p53-/- colorectal cancer cells. We monitored kinase activity in immunoprecipitation, protein expression by immunoblotting, and cell death by multiparametric flow cytometry. A xenograft colorectal cancer model was used to study antitumor activity in vivo.

RESULTS

Treatment of p53+/+ colorectal cancer cells with pharmacologic inhibitors of GSK3beta resulted in sustained elevation of p53, with up-regulation of p21(Waf1/Cip1) and loss of survivin levels. Molecular targeting of GSK3beta by overexpression of a GSK3beta dominant-negative mutant, or acute-silencing of GSK3beta by RNA interference, reproduced the induction of transcriptionally active p53 in colorectal cancer cells. This pathway was recapitulated by deregulated Wnt/T-cell factor signaling, with elevation of the tumor suppressor p14ARF, and reduced expression of the p53 antagonist, MDM2. Rather than cell cycle arrest, GSK3beta blockade resulted in p53-dependent apoptosis, which was contributed by acute loss of survivin and inhibition of colorectal cancer growth in mice.

CONCLUSIONS

Acute ablation of GSK3beta in colorectal cancer cells activates p53-dependent apoptosis and antagonizes tumor growth. This pathway may be exploited for rational treatment of colorectal cancer patients retaining wild-type p53.

Priorities and standards in pharmacogenetic research

The current enthusiasm for pharmacogenetics draws much of its inspiration from the relatively few examples of polymorphisms that have marked and seemingly clinically relevant effects on drug response. In this regard, pharmacogenetic research has paralleled the study of human disease, which has enjoyed success in identifying mutations underlying mendelian conditions. Progress in deciphering the genetics of complex diseases, involving the interaction of multiple genes with each other and with the environment has been considerably less successful. In most instances, drug responses will probably also prove to be complex, influenced by both the environment and multiple genetic factors. For pharmacogenetics to deliver on its potential, this complexity will need to be recognized and accommodated, both in basic research and in clinical application of pharmacogenetics. As the attention of researchers begins to shift toward more systematic pharmacogenetic investigations, we suggest some priorities and standards for pharmacogenetic research.

Proteomic Characterization of the Angiogenesis Inhibitor SU6668 Reveals Multiple Impacts on Cellular Kinase Signaling

Knowledge about molecular drug action is critical for the development of protein kinase inhibitors for cancer therapy. Here, we establish a chemical proteomic approach to profile the anticancer drug SU6668, which was originally designed as a selective inhibitor of receptor tyrosine kinases involved in tumor vascularization. By employing immobilized SU6668 for the affinity capture of cellular drug targets in combination with mass spectrometry, we identified previously unknown targets of SU6668 including Aurora kinases and TANK-binding kinase 1. Importantly, a cell cycle block induced by SU6668 could be attributed to inhibition of Aurora kinase activity. Moreover, SU6668 potently suppressed antiviral and inflammatory responses by interfering with TANK-binding kinase 1-mediated signal transmission. These results show the potential of chemical proteomics to provide rationales for the development of potent kinase inhibitors, which combine rather unexpected biological modes of action by simultaneously targeting defined sets of both serine/threonine and tyrosine kinases involved in cancer progression.

Role of contractile prostaglandins and Rho-kinase in growth factor-induced airway smooth muscle contraction

Background

In addition to their proliferative and differentiating effects, several growth factors are capable of inducing a sustained airway smooth muscle (ASM) contraction. These contractile effects were previously found to be dependent on Rho-kinase and have also been associated with the production of eicosanoids. However, the precise mechanisms underlying growth factor-induced contraction are still unknown. In this study we investigated the role of contractile prostaglandins and Rho-kinase in growth factor-induced ASM contraction.

Methods

Growth factor-induced contractions of guinea pig open-ring tracheal preparations were studied by isometric tension measurements. The contribution of Rho-kinase, mitogen-activated protein kinase (MAPK) and cyclooxygenase (COX) to these reponses was established, using the inhibitors Y-27632 (1 μM), U-0126 (3 μM) and indomethacin (3 μM), respectively. The Rho-kinase dependency of contractions induced by exogenously applied prostaglandin F_2α (PGF_2α) and prostaglandin E₂ (PGE₂) was also studied. In addition, the effects of the selective FP-receptor antagonist AL-8810 (10 μM) and the selective EP₁-antagonist AH-6809 (10 μM) on growth factor-induced contractions were investigated, both in intact and epithelium-denuded preparations. Growth factor-induced PGF_2α-and PGE₂-release in the absence and presence of Y-27632, U-0126 and indomethacin, was assessed by an ELISA-assay.

Results

Epidermal growth factor (EGF)-and platelet-derived growth factor (PDGF)-induced contractions of guinea pig tracheal smooth muscle preparations were dependent on Rho-kinase, MAPK and COX. Interestingly, growth factor-induced PGF_2α-and PGE₂-release from tracheal rings was significantly reduced by U-0126 and indomethacin, but not by Y-27632. Also, PGF_2α-and PGE₂-induced ASM contractions were largely dependent on Rho-kinase, in contrast to other contractile agonists like histamine. The FP-receptor antagonist AL-8810 (10 μM) significantly reduced (approximately 50 %) and the EP₁-antagonist AH-6809 (10 μM) abrogated growth factor-induced contractions, similarly in intact and epithelium-denuded preparations.

Conclusion

The results indicate that growth factors induce ASM contraction through contractile prostaglandins – not derived from the epithelium – which in turn rely on Rho-kinase for their contractile effects.

Quantifying molecular specificity of alphavbeta3 integrin-targeted optical contrast agents with dynamic optical imaging

Dynamic fluorescence images were obtained from a subcutaneous human Kaposi's sarcoma tumor (KS1767) model immediately following the intravenous injection of an integrin-targeting cyanine dye conjugate, Cy5.5-c(KRGDf). The fluorescence images, acquired via an intensified charge-coupled device detection system, were used in conjunction with a pharmacokinetic (PK) model to determine kinetic properties of target binding in the presence and absence of a competitive ligand, free c(KRGDf). The results indicate that the conjugate dye behaves similarly in normal tissue to the free Cy5.5 dye while it possesses increased uptake in tumor tissue. The change in pharmacokinetic parameters obtained from dynamic imaging of Cy5.5-c(KRGDf) after administration of c(KRGDf) as a competitive ligand to the integrin receptor suggests that (i) the increased uptake of Cy5.5-c(KRGDf) is molecularly specific and that (ii) receptor turnover occurs within 24 h. In addition, PK analysis enables quantification of an in vivo c(KRGDf) binding constant attributable to integrin binding. In vivo pharmacokinetic analysis based on rapid and dynamic optical imaging may be potentially useful for evaluating the presence and turnover rate of disease markers that are potential targets of molecular medicine.