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21,245 result(s) for "Neoplasms, Experimental - drug therapy"
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Validation of Core Ingredients and Molecular Mechanism of Cinobufotalin Injection Against Liver Cancer
Cinobufotalin injection has obvious curative effects on liver cancer patients with less toxicity and fewer side effects than other therapeutic approaches. However, the core ingredients and mechanism underlying these anti-liver cancer effects have not been fully clarified due to its complex composition. Multidimensional network analysis was used to screen the core ingredients, key targets and pathways underlying the therapeutic effects of cinobufotalin injection on liver cancer, and and experiments were performed to confirm the findings. By construction of ingredient networks and integrated analysis, eight core ingredients and ten key targets were finally identified in cinobufotalin injection, and all of the core ingredients are tightly linked with the key targets, and these key targets are highly associated with the cell cycle-related pathways, supporting that both cinobufotalin injection and its core ingredients exert anti-liver cancer roles by blocking cell cycle-related pathways. Moreover, and experiments confirmed that either cinobufotalin injection or one of its core ingredients, cinobufagin, significantly inhibited cell proliferation, colony formation, cell cycle progression and xenograft tumor growth, and the key target molecules involved in the cell cycle pathway such as CDK1, CDK4, CCNB1, CHEK1 and CCNE1, exhibit consistent changes in expression after treatment with cinobufotalin injection or cinobufagin. Interestingly, some key targets CDK1, CDK4, PLK1, CHEK1, TTK were predicted to bind with multiple of core ingredients of cinobufotalin injection, and the affinity between one of the critical ingredients cinobufagin and key target CDK1 was further confirmed by SPR assay. Cinobufotalin injection was confirmed to includes eight core ingredients, and they play therapeutic effects in liver cancer by blocking cell cycle-related pathways, which provides important insights for the mechanism of cinobufotalin injection antagonizing liver cancer and the development of novel small molecule anti-cancer drugs.
Targeted therapy for HER2 positive breast cancer
Introduction Breast cancer is the second most common cause of death for women behind lung cancer and the most common cause of cancer deaths for women aged 45–55 years old (CDC.gov 2012). Although there continue to be enormously large numbers of disease incidence, deaths have been declining due to the disease with two hallmark time frames. The first occurred during the mid to late 1980’s when hormonal therapy was introduced as a treatment for ER/PR positive breast cancer. The second occurred in the late 1990’s when trastuzumab was introduced in treating HER2 positive breast cancer. These remarkable accomplishments in developing novel targeted therapies for breast cancer, along with a better understanding of the disease biology have improved disease outcome over the past 20 years. This article reviews the data presented at 2012 American Society of Clinical Oncology and 2012 San Antonio Breast Cancer Symposium regarding progress made in the field of HER2 positive breast cancer and examines the future of HER2 targeted therapy.
Epithelial-to-mesenchymal transition is not required for lung metastasis but contributes to chemoresistance
The role of epithelial-to-mesenchymal transition (EMT) in metastasis is a longstanding source of debate, largely owing to an inability to monitor transient and reversible EMT phenotypes in vivo . Here we establish an EMT lineage-tracing system to monitor this process in mice, using a mesenchymal-specific Cre-mediated fluorescent marker switch system in spontaneous breast-to-lung metastasis models. We show that within a predominantly epithelial primary tumour, a small proportion of tumour cells undergo EMT. Notably, lung metastases mainly consist of non-EMT tumour cells that maintain their epithelial phenotype. Inhibiting EMT by overexpressing the microRNA miR-200 does not affect lung metastasis development. However, EMT cells significantly contribute to recurrent lung metastasis formation after chemotherapy. These cells survived cyclophosphamide treatment owing to reduced proliferation, apoptotic tolerance and increased expression of chemoresistance-related genes. Overexpression of miR-200 abrogated this resistance. This study suggests the potential of an EMT-targeting strategy, in conjunction with conventional chemotherapies, for breast cancer treatment. An epithelial-to-mesenchymal transition (EMT) lineage-tracing system in a mouse model of breast-to-lung metastasis reveals that although some cells undergo EMT in a primary epithelial tumour, the lung metastases mainly arise from cells that have not undergone EMT; in addition, cells that have undergone EMT appear more resistant to chemotherapy. No requirement for EMT in metastasis It has been suggested that epithelial-to-mesenchymal transition (EMT), in which epithelial cells depolarize and adopt a fibroblast-like morphology, is a requirement for metastasis to occur. Other studies imply that the importance of EMT relies on cell-culture-based manipulation of EMT regulators. In this issue of Nature , two groups present results that suggest that EMT is not a prerequisite for metasasis. Dingcheng Gao and colleagues trace the fate of cells that have undergone EMT in mouse model for breast-to-lung metastasis. They find that although some cells undergo EMT in a primary epithelial tumour, the lung metastases mainly contain cells that have not undergone EMT. However, cells that have undergone EMT appear more resistant to chemotherapy. A microRNA that targets key EMT regulators is shown not to affect metastasis, but to reduce survival of EMT cells following chemotherapy. Raghu Kalluri and colleagues delete Twist or Snail — transcription factors that induce EMT — in a mouse model for pancreatic ductal adenocarcinoma. This leads to an increase in cell proliferation, and a greater sensitivity to chemotherapeutic agent gemcitabine, with no effect on invasion and metastasis.
In vivo molecular target assessment of matrix metalloproteinase inhibition
A number of different matrix metalloproteinase (MMP) inhibitors have been developed as cytostatic and anti-angiogenic agents and are currently in clinical testing. One major hurdle in assessing the efficacy of such drugs has been the inability to sense or image anti-proteinase activity directly and non-invasively in vivo . We show here that novel, biocompatible near-infrared fluorogenic MMP substrates can be used as activatable reporter probes to sense MMP activity in intact tumors in nude mice. Moreover, we show for the first time that the effect of MMP inhibition can be directly imaged using this approach within hours after initiation of treatment using the potent MMP inhibitor, prinomastat (AG3340). The developed probes, together with novel near-infrared fluorescence imaging technology will enable the detailed analysis of a number of proteinases critical for advancing the therapeutic use of clinical proteinase inhibitors.
Rb1 and Trp53 cooperate to suppress prostate cancer lineage plasticity, metastasis, and antiandrogen resistance
Prostate cancer relapsing from antiandrogen therapies can exhibit variant histology with altered lineage marker expression, suggesting that lineage plasticity facilitates therapeutic resistance. The mechanisms underlying prostate cancer lineage plasticity are incompletely understood. Studying mouse models, we demonstrate that Rb1 loss facilitates lineage plasticity and metastasis of prostate adenocarcinoma initiated by Pten mutation. Additional loss of Trp53 causes resistance to antiandrogen therapy. Gene expression profiling indicates that mouse tumors resemble human prostate cancer neuroendocrine variants; both mouse and human tumors exhibit increased expression of epigenetic reprogramming factors such as Ezh2 and Sox2. Clinically relevant Ezh2 inhibitors restore androgen receptor expression and sensitivity to antiandrogen therapy. These findings uncover genetic mutations that enable prostate cancer progression; identify mouse models for studying prostate cancer lineage plasticity; and suggest an epigenetic approach for extending clinical responses to antiandrogen therapy.
Selective in vivo metabolic cell-labeling-mediated cancer targeting
Metabolic labeling of the cell surface with a caged azide sugar enabled cleavage-mediated activation by enzymes overexpressed in cancer cells, allowing enhanced targeted delivery of a doxorubicin conjugate through copper-free click chemistry. Distinguishing cancer cells from normal cells through surface receptors is vital for cancer diagnosis and targeted therapy. Metabolic glycoengineering of unnatural sugars provides a powerful tool to manually introduce chemical receptors onto the cell surface; however, cancer-selective labeling still remains a great challenge. Herein we report the design of sugars that can selectively label cancer cells both in vitro and in vivo . Specifically, we inhibit the cell-labeling activity of tetraacetyl- N -azidoacetylmannosamine (Ac 4 ManAz) by converting its anomeric acetyl group to a caged ether bond that can be selectively cleaved by cancer-overexpressed enzymes and thus enables the overexpression of azido groups on the surface of cancer cells. Histone deacetylase and cathepsin L-responsive acetylated azidomannosamine, one such enzymatically activatable Ac 4 ManAz analog developed, mediated cancer-selective labeling in vivo , which enhanced tumor accumulation of a dibenzocyclooctyne–doxorubicin conjugate via click chemistry and enabled targeted therapy against LS174T colon cancer, MDA-MB-231 triple-negative breast cancer and 4T1 metastatic breast cancer in mice.
Potential role of intratumor bacteria in mediating tumor resistance to the chemotherapeutic drug gemcitabine
Growing evidence suggests that microbes can influence the efficacy of cancer therapies. By studying colon cancer models, we found that bacteria can metabolize the chemotherapeutic drug gemcitabine (2′,2′-difluorodeoxycytidine) into its inactive form, 2′,2′-difluorodeoxyuridine. Metabolism was dependent on the expression of a long isoform of the bacterial enzyme cytidine deaminase (CDDL), seen primarily in Gammaproteobacteria. In a colon cancer mouse model, gemcitabine resistance was induced by intratumor Gammaproteobacteria, dependent on bacterial CDDL expression, and abrogated by cotreatment with the antibiotic ciprofloxacin. Gemcitabine is commonly used to treat pancreatic ductal adenocarcinoma (PDAC), and we hypothesized that intratumor bacteria might contribute to drug resistance of these tumors. Consistent with this possibility, we found that of the 113 human PDACs that were tested, 86 (76%) were positive for bacteria, mainly Gammaproteobacteria.
Metabolomic changes of the multi (-AGC-) kinase inhibitor AT13148 in cells, mice and patients are associated with NOS regulation
IntroductionTo generate biomarkers of target engagement or predictive response for multi-target drugs is challenging. One such compound is the multi-AGC kinase inhibitor AT13148. Metabolic signatures of selective signal transduction inhibitors identified in preclinical models have previously been confirmed in early clinical studies. This study explores whether metabolic signatures could be used as biomarkers for the multi-AGC kinase inhibitor AT13148.ObjectivesTo identify metabolomic changes of biomarkers of multi-AGC kinase inhibitor AT13148 in cells, xenograft / mouse models and in patients in a Phase I clinical study.MethodsHILIC LC–MS/MS methods and Biocrates AbsoluteIDQ™ p180 kit were used for targeted metabolomics; followed by multivariate data analysis in SIMCA and statistical analysis in Graphpad. Metaboanalyst and String were used for network analysis.ResultsBT474 and PC3 cells treated with AT13148 affected metabolites which are in a gene protein metabolite network associated with Nitric oxide synthases (NOS). In mice bearing the human tumour xenografts BT474 and PC3, AT13148 treatment did not produce a common robust tumour specific metabolite change. However, AT13148 treatment of non-tumour bearing mice revealed 45 metabolites that were different from non-treated mice. These changes were also observed in patients at doses where biomarker modulation was observed. Further network analysis of these metabolites indicated enrichment for genes associated with the NOS pathway. The impact of AT13148 on the metabolite changes and the involvement of NOS-AT13148- Asymmetric dimethylarginine (ADMA) interaction were consistent with hypotension observed in patients in higher dose cohorts (160-300 mg).ConclusionAT13148 affects metabolites associated with NOS in cells, mice and patients which is consistent with the clinical dose-limiting hypotension.
Targeting of tumour-infiltrating macrophages via CCL2/CCR2 signalling as a therapeutic strategy against hepatocellular carcinoma
ObjectiveHepatocellular carcinoma (HCC) is an aggressive malignancy with limited effective treatment options. An alternative strategy is to target cells, such as tumour-infiltrating macrophages, in the HCC tumour microenvironment. The CCL2/CCR2 axis is required for recruitment of monocytes/macrophages and is implicated in various aspects of liver pathology, including HCC. We investigated the feasibility of CCL2/CCR2 as a therapeutic target against HCC.DesignCCL2 expression was analysed in two independent HCC cohorts. Growth of three murine HCC cells was evaluated in an orthotopic model, a postsurgical recurrence model and a subcutaneous model in mice after blocking CCL2/CCR2 axis by a novel CCR2 antagonist or knocking out of host CCR2. In vivo macrophage or T cell depletion and in vitro cell coculture were further conducted to investigate CCL2/CCR2-mediated crosstalk between tumour-associated macrophages (TAMs) and tumour cells.ResultCCL2 is overexpressed in human liver cancers and is prognostic for patients with HCC. Blockade of CCL2/CCR2 signalling with knockout of CCR2 or with a CCR2 antagonist inhibits malignant growth and metastasis, reduces postsurgical recurrence, and enhances survival. Further, therapeutic blocking of the CCL2/CCR2 axis inhibits the recruitment of inflammatory monocytes, infiltration and M2-polarisation of TAMs, resulting in reversal of the immunosuppression status of the tumour microenvironment and activation of an antitumorous CD8+ T cell response.ConclusionsIn patients with liver cancer, CCL2 is highly expressed and is a prognostic factor. Blockade of CCL2/CCR2 signalling suppresses murine liver tumour growth via activating T cell antitumour immune response. The results demonstrate the translational potential of CCL2/CCR2 blockade for treatment of HCCs.
Iron oxide nanoparticles inhibit tumour growth by inducing pro-inflammatory macrophage polarization in tumour tissues
Until now, the Food and Drug Administration (FDA)-approved iron supplement ferumoxytol and other iron oxide nanoparticles have been used for treating iron deficiency, as contrast agents for magnetic resonance imaging and as drug carriers. Here, we show an intrinsic therapeutic effect of ferumoxytol on the growth of early mammary cancers, and lung cancer metastases in liver and lungs. In vitro , adenocarcinoma cells co-incubated with ferumoxytol and macrophages showed increased caspase-3 activity. Macrophages exposed to ferumoxytol displayed increased mRNA associated with pro-inflammatory Th1-type responses. In vivo , ferumoxytol significantly inhibited growth of subcutaneous adenocarcinomas in mice. In addition, intravenous ferumoxytol treatment before intravenous tumour cell challenge prevented development of liver metastasis. Fluorescence-activated cell sorting (FACS) and histopathology studies showed that the observed tumour growth inhibition was accompanied by increased presence of pro-inflammatory M1 macrophages in the tumour tissues. Our results suggest that ferumoxytol could be applied ‘off label’ to protect the liver from metastatic seeds and potentiate macrophage-modulating cancer immunotherapies. The Food and Drug Administration (FDA)-approved iron supplement ferumoxytol, which contains iron oxide nanoparticles, can suppress growth of early mammary cancers and lung cancer metastasis by inducing pro-inflammatory M1 type macrophage polarization in the tumour tissue, offering a new ‘off label’ application for an approved drug.