Different Types Of Tumor Cells Research Articles

An antimicrobial peptide containing NGR motif has potent antitumor activity against CD13+ and CD13− tumor cells

Antimicrobial peptides (AMPs) with Asn-Gly-Arg (NGR) motif have potent cytotoxicity, preferably against tumor cells due to their binding to CD13 on tumor cells. However, the importance of αvβ3 expression for antitumor activity of AMPs containing NGR has not been clarified. This study was aimed at designing a new AMP containing NGR and testing their biological activity against different types of tumor cells with varying CD13 and αvβ3 expression. We first synthesized the new AMP containing NGR motif (CK21), which effectively entered into CD13+ HT-1080, but less into CD13- αvβ3+ MDA-MB-435 and further less into stable αvβ3-silencing MDA-MB-435 cells. Furthermore, CK21 displayed dose-dependent antiproliferation against these tumor cells and induced cell cycling arrest at G2/M phases and apoptosis of these tumor cells. In addition, CK21 inhibited the invasion of these tumor cells in vitro and inhibited the growth of implanted tumor cells in vivo. Particularly, the antitumor effect of CK21 in CD13+ HT-1080 was stronger than that of CD13- αvβ3+ MDA-MB-435 and much stronger than that of stable αvβ3-silencing MDA-MB-435. Our data indicated that the new AMPs containing NGR had potent antitumor activity against CD13+ or αvβ3+ tumor cells, preferably against CD13+ tumor cells, possibly through binding to CD13 or αvβ3 on tumor cells.

Interleukin-5 facilitates lung metastasis by modulating the immune microenvironment.

Although the lung is the most common metastatic site for cancer cells, biologic mechanisms regulating lung metastasis are not fully understood. Using heterotopic and intravenous injection models of lung metastasis in mice, we found that IL5, a cytokine involved in allergic and infectious diseases, facilitates metastatic colonization through recruitment of sentinel eosinophils and regulation of other inflammatory/immune cells in the microenvironment of the distal lung. Genetic IL5 deficiency offered marked protection of the lungs from metastasis of different types of tumor cells, including lung cancer, melanoma, and colon cancer. IL5 neutralization protected subjects from metastasis, whereas IL5 reconstitution or adoptive transfer of eosinophils into IL5-deficient mice exerted prometastatic effects. However, IL5 deficiency did not affect the growth of the primary tumor or the size of metastatic lesions. Mechanistic investigations revealed that eosinophils produce CCL22, which recruits regulatory T cells to the lungs. During early stages of metastasis, Treg created a protumorigenic microenvironment, potentially by suppressing IFNγ-producing natural killer cells and M1-polarized macrophages. Together, our results establish a network of allergic inflammatory circuitry that can be co-opted by metastatic cancer cells to facilitate lung colonization, suggesting interventions to target this pathway may offer therapeutic benefits to prevent or treat lung metastasis.

Role of runt-related transcription factor 2 in signal network of tumors as an inter-mediator

Runt-related transcription factor 2 (RUNX2) is a member of the polyomavirus enhancer-binding protein 2/core-binding factor superfamily. RUNX2 is known for its contribution to osteoblast phenotype and bone formation. In recent years, increasing attention has been focused on the relationship of Runx2 with tumorigenesis. In different types of tumor cells, RUNX2 cooperates with its co-activators or co-inhibitors, and mediates the responses of cells to various signaling pathways that are hyperactive in tumors. Thus, several downstream target genes of RUNX2 are activated when RUNX2 interacts with its co-factors, leading to a variety of effects on tumor cells (epithelial–mesenchymal transition, metastasis, proliferation, and osteolytic lesion). This review focuses on the involvement of RUNX2 in tumor cells in the crosstalk of diverse signaling pathways and its multiple functions to develop optimal and feasible approaches for clinical treatment based on the functions of RUNX2.

Gene Expression Study on Similarity Effect of Thymoquinone on Epithelial Breast Cancer and Colorectal Cancer Cell Lines

Adenocarcinoma is known as a common type of cancer which includes 85% of breast carcinoma and 95% of colorectal carcinoma. Up until now, the cytotoxic effect of Thymoquinone on different types of tumor cells has been reported. It was hypothesized that Thymoquinone has similar effect on cancer arising from epithelial cells through gene expression analysis in MCF7 breast cancer and HT-29 colon cancer cell lines. The quantity and quality of RNA samples were identified using RNeasyPlus Mini kit and RNA 6000 Nano LabChip kit, respectively. The purified RNA samples of MCF7 cells were used in two-color 8×60K cDNA array platform with SurePrint Agilent technology. The hybridized cRNA/cDNA probes were identified due to labeling with red and green cyanine dyes using GEX hybridization buffer HI-RPM. LOWESS normalization reduced the dye bias on the array slide using feature extraction software. Gene ontology analysis was done after performing different steps of filtering to reduce not satisfied genes using Gene Spring software. Two-step RT-qPCR assay using Taq Man fast advanced master mix analyzed the most up and down regulated genes in MCF7 compared to HT-29 cancer cell lines. The 10 different cancer cell lines in a form of universal reference RNA was used as standard data set comparison and as a positive control RNA in cDNA array and RT-qPCR assay, respectively. The T-test statistical analysis of independent samples showed that there is no significant difference between two types of cell lines due to Thymoquinone treatment with p-value 0.844. Among the selected genes; CARD16, UGT1A8, SLC7A11, IFIT1, IF16 and IFIT3 were expressed significantly (0.009, 0.0001, 0.037, 0.098, 0.0001 and 0.033, respectively) in breast cancer compare to colon cancer cells. The findings indicated similar effect of Thymoquinone on cancer arising from epithelial cells.

TM-14 * THE ANGIOGENIC SWITCH LEADS TO A METABOLIC SWITCH IN HUMAN GLIOBLASTOMA

Invasion and angiogenesis are two of the major hallmarks of glioblastoma growth. While tumor cells in angiogenic areas undergo hypoxic stress, invasive tumor cells are often found in less hypoxic areas and in close vicinity to brain vessels. This difference in microenvironment most likely influences the metabolic profile of these two different types of tumor cells. However, there is a lack of suitable in vivo models for malignant glioma to experimentally separate invasive and angiogenic tumor cells in order to analyze their metabolism. In the present study we used a human GBM xenograft model with EGFR amplification that grows invasive and independent of angiogenesis. This tumor undergoes an angiogenic switch upon overexpression of a dominant-negative EGFR mutant. Here, we show that the transcription factors Smad3, BHLHE40, CEB/P and STAT3 are central transcriptional regulators of the angiogenic switch in this model. By using the REMBRANDT database to assess the clinical relevance of our model, we found that genes upregulated in the angiogenic xenografts are also upregulated in patient GBMs compared to low grades, while the genes upregulated in the invasive tumors are upregulated in low-grade gliomas compared to GBMs. Within the xenograft model, we analyzed the metabolic differences between invasive and angiogenic tumor phenotypes. In vivo MRI spectroscopy showed an upregulation of lactate and glutamine in the angiogenic compared to invasive xenografts. The upregulation of glycolysis in angiogenic xenografts was confirmed by enzymehistochemistry of key enzymes, which in addition showed a substantial upregulation of pentose-phosphate pathway activity. Analysis of mitochondrial respiratory chain revealed reduction of complex I in angiogenic xenografts compared to invasive xenografts. Thus, the use of glycolysis for energy production within human GBMs is highly dependent on the specific microenvironment. The metabolic flexibility of GBM cells highlights the difficulty of targeting one specific metabolic pathway for therapy.

Abstract 1158: Microtubule perturbation regulates remodeling of tumor microenvironment by modulating the composition of tumor cell secretome

Abstract Microtubules (MTs) represent one of the most effective targets in cancer chemotherapy. However, MT-targeting drugs, such as the taxanes, often fail in the metastatic setting and mechanisms underlying drug resistance are poorly elucidated. An important process during tumor development and metastasis involves the dynamic remodeling of the 3D microenvironment surrounding the tumor cells which enables them to successfully proliferate and metastasize. We hypothesized that tumor cell MTs may regulate the cellular signaling process that controls tumor-mediated remodeling of the microenvironment by paracrine activation of fibroblasts. To assess the role of MT dynamics in the secretion of factors from the tumor cells that mediate communication with the microenvironment, we collected conditioned medium (CM) from untreated or paclitaxel (PTX)-pre-treated metastatic breast cancer MDA-MB-231 cells and applied it to HMF3S human mammary fibroblasts. We observed that CM from untreated 231 cells resulted in fibroblast activation as evidenced by their increased directional 3D cell motility towards a serum gradient. CM from PTX-pretreated 231 cells, at concentrations that suppress MT dynamics, but not from the PTX-resistant β-tubulin mutation 231 clone, 231K20T cells, did not result in activation of fibroblasts' 3D motility, suggesting that MT-mediated secretion of soluble factor(s) (secretome) underlies fibroblast activation. Mass-spectrometry analysis of CM derived from untreated or PTX-pretreated 231 cells identified proteins whose secretion was diminished following suppression of MT dynamics and which are involved in cell motility, cell-cell communication, or ECM remodeling, such as TGFβ, CTGF, c-Met, fibronectin, and lysyl oxidase 2. Treatment of 231-derived CM with an anti-TGFβ blocking antibody diminished HMF3S fibroblast motility in 3D, suggesting that the presence of TGFβ in the tumor cell secretome mediated the activation of tumor associated fibroblasts. To further probe the MT-dependent regulation of TGFβ secretion we showed that PTX treatment prevented trafficking of intracellular TGFβ to the cell surface in 231 cells, likely underlying its reduced secretion. Confocal reflectance and two-photon microscopic imaging revealed that CM treatment of HMF3S fibroblasts induced significant collagen remodeling comparable to treatment with exogenous TGFβ alone. Our findings point to a novel role of interphase MTs in tumor cell secretome and raise the possibility that MTs may regulate secretion of distinct soluble factors in different types of tumor cells, which then mediate the communication between tumor cell compartment and the tumor microenvironment. These novel insights have significant implications for the mechanism of action and resistance to MT inhibitors. Citation Format: Katsuhiro Kita, Andy Tran, Lewis M. Brown, Duane C. Hassane, Shawn Carey, Alexandre Matov, Cynthia A. Reinhart-King, Paraskevi Giannakakou. Microtubule perturbation regulates remodeling of tumor microenvironment by modulating the composition of tumor cell secretome. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1158. doi:10.1158/1538-7445.AM2014-1158

Organotin complexes containing carboxylate ligands with maleimide and naphthalimide derived partial structures: TrxR inhibition, cytotoxicity and activity in resistant cancer cells

Di-n-butyltin(IV) carboxylate and tri-n-butyltin(IV) carboxylate derivatives have demonstrated strong cytotoxic effects in different types of tumor cells. Complexes with carboxylate ligands that contain maleimide and naphthalimide derived partial structures were synthesized, characterized and investigated for inhibition of the tumor-relevant enzyme thioredoxin reductase and antiproliferative effects in cancer cells. The complexes were moderate inhibitors of thioredoxin reductase with activities in the micromolar range and triggered strong cytotoxic effects in MCF-7 breast cancer and HT-29 colon carcinoma cells. Interestingly, selected complexes were highly active in vincristine and daunorubicin resistant Nalm-6 cells.

Crosstalk between mitochondrial ROS and depolarization in the potentiation of TRAIL-induced apoptosis in human tumor cells

We previously showed that membrane-depolarizing agents such as K+ and ATP-sensitive potassium (KATP) channel inhibitors potentiate tumor necrosis factor-related apoptosis‑inducing ligand (TRAIL)-induced apoptosis in human melanoma cells, but not in normal melanocytes. In this study, we investigated whether the tumor-selective effect of depolarization was observed among different tumor cell types and the mechanisms by which depolarization potentiates death pathways. We found that K+ and KATP channel inhibitors elicited similar apoptosis-potentiating effects in human tumor cells with different origins, including leukemia, melanoma and lung cancer cells. In contrast, minimal potentiation of apoptosis was observed in non-transformed lung cells. The potentiation was associated with increased mitochondrial and endoplasmic reticulum stress death pathways. Upregulation of surface TRAIL receptor-2 expression and modulation of the caspase-3 activation pathway seemed to play roles in the enhancement of death signaling. Moreover, the results showed that depolarization and mitochondria‑derived reactive oxygen species (mROS) mutually regulated one another. Depolarization potentiated TRAIL-induced mROS accumulation. Conversely, scavenging of mROS by the antioxidant MnTBaP reduced depolarization, whereas mROS accumulation caused by metabolic inhibitors potentiated the depolarization. These findings suggest a positive loop between depolarization and mROS accumulation. This may provide a rationale for the tumor-selective cytotoxicity and/or potentiation of TRAIL cytotoxicity of a wide variety of ROS-producing substances in different types of tumor cells.

Single-cell clones of liver cancer stem cells have the potential of differentiating into different types of tumor cells

Cancer stem cells (CSCs) are believed to be a promising target for cancer therapy because these cells are responsible for tumor development, maintenance and chemotherapy resistance. Finding out the critical factors regulating CSC fate is the key for target therapy of CSCs. Just as normal stem cells are regulated by their microenvironment (niche), CSCs are also regulated by cells in the tumor microenvironment. However, whether various tumor microenvironments can induce CSCs to differentiate into different cancer cells is not clear. Here, we show that single-cell-cloned CSCs, accidentally obtained from a human liver cancer microvascular endothelial cells, express classic stem cell markers, genes associated with self-renewal and pluripotent factors and possess colony-forming ability in vitro and the ability of serial transplantation in vivo. The single-cell-cloned CSCs treated with the different tumor cell/tissue-derived conditioned culture medium, which is a mimic of carcinoma microenvironment, could differentiate into corresponding tumor cells and express specific markers of the respective type of tumor cells at the gene, protein and cell levels, respectively. Interestingly, this multilineage differentiation potential of single-cell-cloned liver CSCs sharply declined after the specific knockdown of octamer-binding transcription factor 4 (Oct4) alone, even though they were under the same induction conditions (carcinoma microenvironments). These data support the hypothesis that single-cell-cloned liver CSCs have the potential of differentiating into different types of tumor cells, and the tumor microenvironment does play a crucial role in deciding differentiation directions. Simultaneously, Oct4 in CSCs is indispensable in this process. These factors are promising targets for liver CSC-specific therapy.

α-Lipoic acid-induced inhibition of proliferation and met phosphorylation in human non-small cell lung cancer cells

α-Lipoic acid (α-LA), a naturally occurring anti-oxidant and co-factor for metabolic enzymes, suppresses the growth of different types of tumor cells. The mechanisms that are responsible for these results, however, remain to be elucidated. In the present study, we investigated the effects of α-LA on the proliferation and activation status of definitive receptor tyrosine kinases, epidermal growth factor receptor (EGFR) and Met/hepatocyte growth factor (HGF) receptor, in gefitinib-sensitive human non-small cell lung cancer cells harboring EGFRs with an activating mutation. The enantiomers R-α-LA and S-α-LA suppressed cell proliferation and increased the level of reactive oxygen species in HCC-827 and PC-9 human non-small cell lung cancer cells in an indistinguishable dose-dependent fashion. A phospho-receptor tyrosine kinase array and cell cycle analysis indicated that α-LA decreased tyrosine phosphorylation levels of EGFR, ErbB2, and Met, and this was associated with an inhibition in the cell-cycle transition from the G1 phase to the S phase without inducing apoptosis. Gefitinib, an inhibitor for EGFR tyrosine kinase, inhibited EGFR tyrosine phosphorylation/activation and proliferation of the cells. Instead, the addition of HGF induced Met tyrosine phosphorylation, and this was associated with a resistance to gefitinib-induced growth inhibition, which meant a gain in proliferative ability. In the presence of gefitinib and HGF, the addition of α-LA suppressed Met tyrosine phosphorylation, and this was associated with an inhibition in cell growth. These results suggest that the suppression of tyrosine phosphorylation/activation of growth factor receptors that is critical for the proliferation of human non-small cell lung cancer cells is a mechanism by which α-LA exerts growth inhibition for cancer cells.

Bisacylimidoselenocarbamates Cause G2/M Arrest Associated with the Modulation of CDK1 and Chk2 in Human Breast Cancer MCF-7 Cells

Bisacylimidoselenocarbamate derivatives (BSC) are potent anticancer agents with a strong cytotoxic activity against different types of tumour cells. Based in phosphatidylserine exposure on the cell membranes we show that BSC treatment resulted in enhanced cell death in leukaemia CCRF-CEM cells. DNA fragmentation detection in breast adenocarcinoma MCF-7 cells showed that BSC triggered cell death is concentration and time dependent. We also show that two of these compounds, BSC 3g and 3n, cause cell-cycle arrest in the late G2/M in MCF-7 cells. Consistent with this, a reduction in CDK1 and CDK2 expression with no change in cyclin A an B1 was observed in this cell line. Activation of caspase-2 was also detected. However, the involvement of the caspase-dependent pathway in the process of cell death induced by either BSC 3g or 3n is discarded since cell death could not be prevented by pretreatment with the pancaspase inhibitor z-VAD-fmk. Moreover, since reduced levels of p21(CIP1) and Chk2 proteins but no change in p53 levels could be detected in MCF-7 cells after BSC 3g or 3n treatment our results suggest that BSC treated cells die from lethal mitosis.

Assessment of Tracer 99mTc(V)-DMSA Uptake as a Measure of Tumor Cell Proliferation In Vitro

PurposeTo examine whether 99mTc(V)-DMSA could be used as a non-invasive measure of cancer cell proliferation.MethodsHuman breast cancer MCF-7, MDA-MB-231 and pII, and prostate cancer PC-3 cell lines were grown to 30, 50 and 100% confluency and pulsed with 99mTc(V)-DMSA in media for 60 min at 37°C. DNA synthesis was analysed by quantification of the S phase using flow cytometry, [methyl-3H]thymidine incorporation and expression of proliferation markers PCNA and Ki-67 using realtime PCR. One way ANOVA was used to compare groups.ResultsIn all cell lines rates of 99mTc(V)-DMSA uptake were inversely related to cell density. This was paralleled by similar trends in S phase proportions, [methyl-3H]thymidine incorporation and expression of PCNA and Ki-67.ConclusionRates of 99mTc(V)-DMSA uptake into different types of tumour cells correlate well with cell density that is useful as a non-invasive measure of tumour cellular proliferation in vivo.

Identification of occult disseminated tumor cells by recombinant herpes simplex virus expressing GFP (HSV(GFP))

To develop a novel rapid protocol for the detection of occult disseminated tumor cells by a recombinant herpes simplex virus expressing GFP (HSV(GFP)). Tumor cells of seven cell lines were exposed to HSV(GFP) and then examined for GFP expression by fluorescence microscopy. Various numbers of tumor cells (10, 100, 1000, 10 000) were mixed into 2 ml human whole blood, separated with lymphocytes separation medium, exposed to HSV(GFP), incubated at 37°C for 6 - 24 h and then counted for the number of green cells under the fluorescence microscope. Some clinical samples including peripheral blood, pleural effusion, ascites, spinal fluid from tumor-bearing patients were screened using this protocol in parallel with routine cytological examination. HSV(GFP) was able to infect all 7 tumor cell lines indicating that the HSV(GFP) can be used to detect different types of tumor cells. The detection sensitivity was 10 cancer cells in 2 ml whole blood. In the clinical samples, there were 4/15 positive by routine cytological examination but 11/15 positive by HSV(GFP), indicating a higher sensitivity of this new protocol. Recombinant herpes simplex virus-mediated green fluorescence is a simple and sensitive technique for the identification of occult disseminated cancer cells including circulating tumor cells (CTCs).

Isolation and identification of cancer stem-like cells from side population of human prostate cancer cells

It has been widely verified by various sorting methods that cancer stem cells (CSCs) exist in different types of tumor cells or tissues. However, due to lack of specific stem cell surface markers, CSCs are very difficult to be separated from some cancer cells, which becomes the key barrier of functional studies of CSCs. The sorting method by side population cells (SP) lays a solid foundation for in-depth and comprehensive study of CSCs. To identify the existence of SP in prostate cancer cell lines, we applied flow cytometry sorting by SP to cultures of prostate cancer cell lines (TSU, LnCap, and PC-3), and the cancer stem-like characteristics of SP were verified through experiments in vitro and in vivo. The proportion of SP in TSU cells was calculated to be 1.60%±0.40% [Formula: see text], and that in PC-3 and LnCap cells was calculated to be 0.80%±0.05% and 0.60%±0.20%, respectively. The colony formation assay demonstrated that the colony formation rate of SP to non-SP sorted from TSU via flow cytometry was 0.495±0.038 to 0.177±0.029 in 500 cells, 0.505±0.026 to 0.169±0.024 in 250 cells, and 0.088±0.016 to 0.043±0.012 in 125 cells respectively. In the in vivo experiments, tumors were observed in all the mice on the 10th day after injecting 50 000 cells subcutaneously in SP group, whereas when 5×10(6) cells were injected in non-SP group, tumors were developed in only 4 out of 8 mice until the 3rd week before the end of the experiment. Our results revealed that prostate cancer cells contain a small subset of cells, called SP, possessing much greater capacity of colony formation and tumorigenic potential than non-SP. These suggest that SP in prostate cancer cells may play a key role in the self-renewal and proliferation, and have the characteristics of cancer stem-like cells. Dissecting these features will provide a new understanding of the function of prostate CSCs in tumorigenicity and transformation.

Compartment-specific bioluminescence imaging platform for the high-throughput evaluation of antitumor immune function

Conventional assays evaluating antitumor activity of immune effector cells have limitations that preclude their high-throughput application. We adapted the recently developed Compartment-Specific Bioluminescence Imaging (CS-BLI) technique to perform high-throughput quantification of innate antitumor activity and to show how pharmacologic agents (eg, lenalidomide, pomalidomide, bortezomib, and dexamethasone) and autologous BM stromal cells modulate that activity. CS-BLI-based screening allowed us to identify agents that enhance or inhibit innate antitumor cytotoxicity. Specifically, we identified compounds that stimulate immune effector cells against some tumor targets but suppressed their activity against other tumor cells. CS-BLI offers rapid, simplified, and specific evaluation of multiple conditions, including drug treatments and/or cocultures with stromal cells and highlights that immunomodulatory pharmacologic responses can be heterogeneous across different types of tumor cells. This study provides a framework to identify novel immunomodulatory agents and to prioritize compounds for clinical development on the basis of their effect on antitumor immunity.

Downregulation of miR-210 expression inhibits proliferation, induces apoptosis and enhances radiosensitivity in hypoxic human hepatoma cells in vitro

Hypoxia is a common feature of solid tumors and an important contributor to tumor radioresistance. miR-210 is the most consistently and robustly induced microRNA under hypoxia in different types of tumor cells and normal cells. In the present study, to explore the feasibility of miR-210 as an effective therapeutic target, lentiviral-mediated anti-sense miR-210 gene transfer technique was employed to downregulate miR-210 expression in hypoxic human hepatoma SMMC-7721, HepG2 and HuH7 cells, and phenotypic changes of which were analyzed. Hypoxia led to an increased hypoxia inducible factor-1α (HIF-1α) and miR-210 expression and cell arrest in the G0/G1 phase in all cell lines. miR-210 downregulation significantly suppressed cell viability, induced cell arrest in the G0/G1 phase, increased apoptotic rate and enhanced radiosensitivity in hypoxic human hepatoma cells. Moreover, apoptosis-inducing factor, mitochondrion-associated, 3 (AIFM3) was identified as a direct target gene of miR-210. AIFM3 downregulation by siRNA attenuated radiation induced apoptosis in miR-210 downregulated hypoxic human hepatoma cells. Taken together, these data suggest that miR-210 might be a potential therapeutic target and specific inhibition of miR-210 expression in combination with radiotherapy might be expected to exert strong anti-tumor effect on hypoxic human hepatoma cells.

Doxorubicin-loaded human serum albumin nanoparticles surface-modified with TNF-related apoptosis-inducing ligand and transferrin for targeting multiple tumor types

Human serum albumin (HSA) nanoparticles (NPs) surface modified with tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) and transferrin, and containing doxorubicin were designed and prepared. Surface amines of HSA were reversibly protected with dimethylmaleic anhydride (DMMA), and HSA-NPs were prepared using a desolvation technique. Furthermore, the surfaces of HSA-NPs were modified with thiolated TRAIL or transferrin using sulfosuccinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate (Sulfo-SMCC). The prepared TRAIL/transferrin plus doxorubicin HSA-NPs were characterized by TEM, FE-SEM, and particle size analysis, and their cytotoxic and apoptotic activities were evaluated in several cancer cell lines, namely, HCT 116, doxorubicin-resistant MCF-7, and CAPAN-1. In addition, the tumor-targeting abilities of NPs were assessed using an infrared imaging system in HCT 116-xenografted nu/nu mice. Results showed that the TRAIL/transferrin/doxorubicin HSA-NPs had remarkable cytotoxic and apoptotic activities in all cancer cells examined with a general or a drug-resistant character, and that these NPs had obvious synergistic cytotoxic effects particularly on CAPAN-1 cells. Moreover, these HSA-NPs were effectively localized to tumors in a HCT 116-xenografted nu/nu mouse over 32 h. The findings of this study suggest that the described TRAIL/transferrin/doxorubicin HSA-NPs are a useful targeting agent capable of killing different types of tumor cells in various tissue organs.

Volumetric and Angiogenic Evaluation of Antitumor Effects with Acoustic Liposome and High-Frequency Ultrasound

Acoustic liposomes (AL) have their inherent echogenicity and can add functionality in serving as drug carriers with tissue specificity. Nonuniform vascular structures and vascular branches/bends are evaluated by imaging the intravascular movement locus of ALs with high-frequency ultrasound (HF-US) imaging. However, the evaluation of antitumor effects on angiogenesis by ALs and HF-US imaging has not been reported. Here, we show that the combination of ALs and an HF-US imaging system is capable of noninvasively evaluating antitumor volumetric and angiogenic effects in preclinical mouse models of various cancers. In this study, the antitumor effects of cisplatin on tumor growth and angiogenesis in mice bearing two different types of tumor cells were assessed. By tracking each AL flowing in the vessel and transferring the images to personal computers, microvessel structures were mapped and reconstructed using the color difference based on SD method. The antitumor effects were confirmed with an in vivo bioluminescence imaging system and immunohistochemical analysis. Our results show that cisplatin inhibits tumor growth by decreasing intratumoral vessel area but does not affect the angiogenesis ratio in the tumor. The vascular occupancy in the outer region of the tumor was larger than that in the inner region; however, both occupancies were similar to those of the control tumor. We propose that this method of mapping microvessels with ALs and an HF-US system can serve as a new molecular imaging method for the assessment of angiogenesis and can be applied to evaluate the antitumor effects by various therapeutic agents.

Enhanced anti-tumor efficacy by co-delivery of doxorubicin and paclitaxel with amphiphilic methoxy PEG-PLGA copolymer nanoparticles

The use of single chemotherapeutic drug has shown some limitations in anti-tumor treatment, such as development of drug resistance, high toxicity and limited regime of clinical uses. The combination of two or more therapeutic drugs is feasible means to overcome the limitations. Co-delivery strategy has been proposed to minimize the amount of each drug and to achieve the synergistic effect for cancer therapies. Attempts have been made to deliver chemotherapeutic drugs simultaneously using drug carriers, such as micelles, liposomes, and inorganic nanoparticles (NPs). Here we reported core-shell NPs that were doubly emulsified from an amphiphilic copolymer methoxy poly(ethylene glycol)-poly(lactide-co-glycolide) (mPEG-PLGA). These NPs offered advantages over other nanocarriers, as they were easy to fabricate by improved double emulsion method, biocompatible, and showed high loading efficacy. More importantly, these NPs could co-deliver hydrophilic doxorubicin (DOX) and hydrophobic paclitaxel (TAX). The drug-loaded NPs possessed a better polydispersity, indicating that they are more readily subject to controlled size distribution. Studies on drug release and cellular uptake of the co-delivery system demonstrated that both drugs were effectively taken up by the cells and released simultaneously. Furthermore, the co-delivery nanocarrier suppressed tumor cells growth more efficiently than the delivery of either DOX or TAX at the same concentrations, indicating a synergistic effect. Moreover, the NPs loading drugs with a DOX/TAX concentration ratio of 2:1 showed the highest anti-tumor activity to three different types of tumor cells. This nanocarrier might have important potential in clinical implications for co-delivery of multiple anti-tumor drugs with different properties.

Abstract 476: Defining two populations of prostate cancer cells with distinct molecular, biological, and tumor-propagating properties

Abstract Prostate cancer (PCa) is a heterogeneous malignancy containing different types of tumor cells. The cellular basis underlying PCa cell heterogeneity and functional importance of different PCa cell populations in maintaining tumor homeostasis and mediating castration-resistant progression remain poorly understood. By whole-genome microarray analysis, time-lapse videomicroscopy, serial tumor transplantations, and other functional assays, here we report the distinct molecular, cell biological, and tumor-propagating properties of PCa cells that express high (i.e., PSA+) and low (PSA−/lo) levels of PSA. PSA−/lo PCa cells are relatively quiescent and resistant to multiple stresses, exhibit high clonogenic potential, and possess long-term tumor-propagating capacity in intact male mice. They preferentially express stem cell-associated genes and epigenetic profiles and can generate PSA+ cells by either asymmetric or symmetric cell division. Of great clinic significance, PSA−/lo PCa cells can initiate robust tumor development in fully castrated hosts and survive experimental androgen-deprivation therapy. In contrast, PSA+ PCa cells, despite being highly tumorigenic in androgen-proficient hosts, possess more limited tumor-propagating capacity, mainly undergo symmetric division, and are sensitive to castration. Our data together suggest that the two populations of PCa cells appear to play differential roles in tumor maintenance and PSA−/lo cells may represent an important source of castration-resistant PCa cells. Our findings have important implications in understanding PCa cell heterogeneity, tumor response to the mainstay antiandrogen therapies, and emergence of castration-resistant PCa. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 476. doi:10.1158/1538-7445.AM2011-476