Chemotherapy In Breast Cancer Cells Research Articles

Epigenetic modulators combination with chemotherapy in breast cancer cells.

Despite the concerning adverse effects on tumour development, epigenetic drugs are very promising in cancer treatment. The aim of this study was to compare the differential effects of standard chemotherapy regimens (FEC: 5-fluorouracil plus epirubicine plus cyclophosphamide) in combination with epigenetic modulators (decitabine, valproic acid): (a) on gene methylation levels of selected tumour biomarkers (LINE-1, uPA, PAI-1, DAPK); (b) their expression status (uPA and PAI-1); (c) differentiation status (5meC and H3K27me3). Furthermore, cell survival as well as changes concerning the invasion capacity were monitored in cell culture models of breast cancer (MCF-7, MDA-MB-231). A significant overall decrease of cell survival was observed in the FEC-containing combination therapies for both cell lines. Methylation results showed a general tendency towards increased demethylation of the uPA and PAI-1 gene promoters for the MCF-7 cells, as well as the proapoptotic DAPK gene in the treatment regimens for both cell lines. The uPA and PAI-1 antigen levels were mainly increased in the supernatant of FEC-only treated MDA-MB-231 cells. DAC-only treatment induced an increase of secreted uPA protein in MCF-7 cell culture, while most of the VPA-containing regimens also induced uPA and PAI-1 expression in MCF-7 cell fractions. Epigenetically active substances can also induce a re-differentiation in tumour cells, as shown by 5meC, H3K27me3 applying ICC. SIGNIFICANCE OF THE STUDY: Epigenetic modulators especially in the highly undifferentiated and highly malignant MDA-MB-231 tumour cells significantly reduced tumour malignancy thus; further clinical studies applying specific combination therapies with epigenetic modulators may be warranted.

Co-delivery of cisplatin and doxorubicin by carboxylic acid functionalized poly (hydroxyethyl methacrylate)/reduced graphene nanocomposite for combination chemotherapy of breast cancer cells

In this study a novel pH-responsive magnetic nanocomposite based on reduced graphene oxide was developed for combination of doxorubicin (Dox)-cisplatin (Cis) delivery to destroy the MCF-7 cell line. For this purpose, polyhydroxyethyl methacrylate (PHEMA) was bonded to the reduced graphene oxide through ATRP polymerization using grafting from method. Then the PHEMA hydroxy groups were converted to succinyloxy groups by polyesterification with succinic anhydride. The physicochemical properties of the nanocomposite were investigated via FTIR, SEM, XRD, DLS and TGA analysis. Unique structure of nanocomposite led to simultaneous encapsulation of Dox (75%) and Cis (82%) through ionic interaction, π–π stacking and hydrogen bonding. The obtained nanocomposite was uptake by MCF-7 cells at early first hour because of nanocomposite small size (below 70 nm). Cell viability assay results revealed that the Dox&Cis-loaded nanocomposite showed the highest rate of MCF-7 cells at lowest concentration (IC50 = 0.798 µg/mL) compared to treatment groups received single drug-loaded nanocomposite and free drugs. Dox&Cis-loaded nanocomposite exhibited a synergistic influence with the combination index (CI) value <1. The cell cycle analysis results revealed that the highest amount of apoptosis (cells population in sub G1 was 75%) was observed in the Dox&Cis-loaded nanocomposite treatment group compared with the single drug-loaded nanocomposite and free drugs. Our findings confirmed that combinational therapy by Dox and Cis graphene oxide-based nanocomposite has increased the cytotoxicity in MCF-7 cells by stimulating the apoptotic response.

SIPA1 enhances SMAD2/3 expression to maintain stem cell features in breast cancer cells.

SIPA1, a GTPase activating protein that negatively regulates Ras-related protein (Rap), is a potential modulator of tumor metastasis and recurrence. In this study, we first showed that SIPA1 facilitated the stemness features of breast cancer cells, such as of tumorsphere formation capability and the expression of stemness marker CD44. In addition, SIPA1 promoted the expression of four stemness-associated transcription factors through increasing the expression of SMAD2 and SMAD3 in vitro and in vivo. The stemness features were abolished by blocking the phosphorylation of SMAD3 with its specific inhibitor SIS3. Furthermore, SIPA1 decreased the breast cancer cell sensitivity to chemotherapy drugs. This effect was, however, competitively reversed by blocking the SMAD3 phosphorylation by SIS3 treatment in breast cancer cells. Taken together, SIPA1 promotes and sustains the stemness of breast cancer cells and their resistance to chemotherapy by increasing the expression of SMAD2 and SMAD3, and blocking SMAD3 phosphorylation could suppress the cancer cell stemness and increase the sensitivity to chemotherapy in breast cancer cells expressing a high level of SIPA1.

Artichoke Polyphenols Sensitize Human Breast Cancer Cells to Chemotherapeutic Drugs via a ROS-Mediated Downregulation of Flap Endonuclease 1.

Combined treatment of several natural polyphenols and chemotherapeutic agents is more effective comparing to the drug alone in inhibiting cancer cell growth. Polyphenolic artichoke extracts (AEs) have been shown to have anticancer properties by triggering apoptosis or reactive oxygen species- (ROS-) mediated senescence when used at high or low doses, respectively. Our aim was to explore the chemosensitizing potential of AEs in order to enhance the efficacy of conventional chemotherapy in breast cancer cells. We employed breast cancer cell lines to assess the potential synergistic effect of a combined treatment of AEs/paclitaxel (PTX) or AEs/adriamycin (ADR) and to determine the underlying mechanisms correlated to this potential therapeutic approach. Our data shows that AEs/PTX reduced cell proliferation by increasing DNA damage response (DDR) mediated by Flap endonuclease 1 (FEN1) downregulation that results into enhanced breast cancer cell sensitivity to chemotherapeutic drugs. We demonstrated that ROS/Nrf2 and p-ERK pathways are two molecular mechanisms involved in the synergistic effect of AEs plus PTX treatment. To highlight the role of ROS herein, we report that the addition of antioxidant N-acetylcysteine (NAC) significantly decreased the antiproliferative effect of the combined treatment. A combined therapy could be able to reduce the dose of chemotherapeutic drugs, minimizing toxicity and side effects. Our results suggest the use of artichoke polyphenols as ROS-mediated sensitizers of chemotherapy paving the way for innovative and promising natural compound-based therapeutic strategies in oncology.

Chemotherapy of Breast Cancer Cells Using Novel pH-Responsive Cellulose-Based Nanocomposites.

Purpose: The objective of the current study was to compare the anticancer efficacy of doxorubicin-loaded cellulose based magnetic (Fe3O4), zinc oxide (ZnO) nanoparticles on and free doxorubicin (DOX) on MCF-7 breast cancer cells. Methods: Novel pH-sensitive cellulose-graft poly acrylic acid based Fe3O4 (Cellulose-g-PAAg- PAcMNPs) and ZnO (Cellulose-g-PAA-g-PAcZnO) nanocomposites were synthesized via polymerization of acrylic acid and modified 3-(trimethoxysilyl) propyl methacrylate onto the cellulosic backbone via reversible addition-fragmentation chain transfer (RAFT) method. Results: Cellulose-g-PAA-g-PAcMNPs and Cellulose-g-PAA-g-PAcZnO nanocarriers with mean diameter of 15 and 38 nm were prepared successfully. DOX was loaded effectively to the ZnO and Fe3O4 nanocarriers via complexing and electrostatic force with great encapsulation efficiency of 99.07% and 98.92%, respectively. DOX-loaded nanocarriers showed obvious pHdependent tumor specific drug release pattern. MTT assay results indicated that IC50 of the DOX loaded Cellulose-g-PAA-g-PAcZnO, DOX loaded Cellulose-g-PAA-g-PAcMNPs and free DOX after 48 hours treatment with MCF7 cell lines were about 24.03, 49.27 and 99.76 μg mL−1, respectively. Therefore both DOX nanoformulations significantly increase antitumor ability compared to free DOX (P < 0.05). The results of MTT assay and DAPI staining revealed that DOX-loaded Cellulose-g-PAA-g-PAcZnO NPs show higher chemotherapy efficiency in MCF7 breast cancer cell line compare to the DOX-loaded Cellulose-g-PAA-g-PAcMNPs due to high interaction of ZnO with DOX. Conclusion: The formation of the complexes between the DOX and ZnO nanoparticles at the chelating sites of the quinone and the phenolic oxygen molecules of DOX, lead to more sustained drug release and enhanced chemotherapy effectiveness by increasing the intracellular concentration of DOX.

The intracellular redox environment modulates the cytotoxic efficacy of single and combination chemotherapy in breast cancer cells using photochemical internalisation.

Background: Photochemical internalisation (PCI) is a light-triggered and site-specific technique that enhances the delivery of therapeutic agents to their intracellular targets using amphiphilic, photosensitizing agents. Methods: This study investigated the effect that the intracellular redox environment of 4T1 breast cancer cells exerts on PCI-facilitated delivery of the type I ribosome inactivating protein, saporin, and the topoisomerase inhibitor, mitoxantrone, either individually or in combination. Buthionine sulfoximime (BSO), a clinically used inhibitor of glutathione synthesis, and the singlet oxygen scavenger, l-histidine, were used to enhance the oxidative and reductive state of the cells respectively. Results: PCI of saporin at 30 nM was effective in reducing cellular viability, which decreased to 16% compared to “dark” controls (P < 0.01). Addition of BSO enhanced PCI efficacy by a further factor of three (P < 0.01), but addition of l-histidine completely inhibited cytotoxicity induced by PCI. The combination of the two cytotoxic agents, saporin and mitoxantrone, with PCI, elicited 14% and 17% reduction in cell viability (P < 0.01) compared to PCI with saporin alone and mitoxantrone alone respectively. Combination treatment with BSO resulted in a further significant reduction in cell viability by 18% (P < 0.01). Conclusions: Our findings show the efficacy of PCI can be manipulated and potentiated by modifying the intracellular redox environment.

Abstract 4914: IFI16 is increased in response to chemotherapeutic agents in breast cancer cells

Abstract Breast cancer is the most common cancer in women worldwide and chemotherapy is one of the standard treatment options for breast cancer. Chemotherapeutic agents induce severe DNA damage in cancer cells, which have mutations in genes related with DNA repair, resulting in cancer cell death. Thus, controlling DNA damage response is an important factor in determining outcome upon chemotherapy. In this study, we identified IFN-γ inducible protein 16 (IFI16) as a regulator of DNA damage response in breast cancer cells. First, we found that the expression of IFI16 was increased in response to chemotherapeutic agents such as 5-fluouracil, doxorubicin and cisplatin. However, changes in mRNA level of IFI16 was not observed, suggesting that IFI16 expression could be regulated by post-translation modification. Second, nuclear fractionation and confocal analysis revealed that expression of nuclear IFI16 was increased and cytoplasmic IFI16 was decreased in response to doxorubicin. Taken together, IFI16 could be a possible candidate for regulating factor of DNA damage response upon chemotherapy in breast cancer cells. Citation Format: Gayoung Lim, Na-Lee Ka, Mi-Ock Lee. IFI16 is increased in response to chemotherapeutic agents in breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr 4914.

Orai3 calcium channel and resistance to chemotherapy in breast cancer cells: the p53 connection

Orai proteins are highly selective calcium channels playing an important role in calcium entry. Orai3 channels are overexpressed in breast cancer (BC) tissues, and involved in their proliferation, cell cycle progression and survival. Herein, we sought to address the involvement of Orai3 in resistance to chemotherapeutic drugs. Using high-throughput approaches, we investigated major changes induced by Orai3 overexpression, including downstream signaling mechanisms involved in BC chemotherapy resistance. Resistance was dependent on external calcium presence and thus Orai3 functionality. This effect allowed a downregulation of the p53 tumor suppressor protein expression via the pro-survival PI3K/Sgk-1/Sek-1 pathway. We demonstrated that p53 degradation occurred not only via Mdm2, but also via another unexpected E3 ubiquitin ligase, Nedd4-2. We found supporting bioinformatic evidence linking Orai3 overexpression and chemoresistance in large human BC data sets. Altogether, our results shed light on the molecular mechanisms activated in BC cells commonly found to overexpress Orai3, allowing resistance to chemotherapeutic drugs.

Abstract 5758: Elevated level of estrogen enhances chemotherapeutic efficacy potentially through epigenetic mechanism in human breast cancer cells

Abstract Effectiveness of chemotherapy depends on the age of breast cancer patients. Breast tissues are estrogen sensitive and the levels of ovarian estrogen are age-dependent variable among the breast cancer patients. Whether this variation in estrogen levels influences the chemotherapeutic efficacy in breast cancer patients is unclear. Therefore, the objective of this study was to determine the effects of natural estrogen 17 beta-estradiol on the efficacy of chemotherapy in breast cancer cells. Estrogen responsive MCF-7 breast cancer cells were long-term exposed to 100 pg/ml estrogen for three months. Using these estrogen exposed MCF-7 cells, the efficacy of chemotherapeutic drugs doxorubicin and cisplatin were determined. The result of cell viability and cell cycle analysis revealed increased efficacy of doxorubicin and cisplatin in estrogen-exposed MCF-7 cells as compared to control MCF-7 cells. Gene expression analysis of marker genes for cell cycle, anti-apoptosis, DNA repair, and drug transporter genes further confirmed the increased efficacy of chemotherapeutic drugs in estrogen-exposed cells at molecular level. To further understand the role of epigenetic mechanism in enhanced chemotherapeutic efficacy by estrogen, cells were pre-treated with epigenetic drugs, 5-Aza-2-deoxycytidine and Trichostatin A before doxorubicin and cisplatin treatments. The enhanced efficacy of doxorubicin and cisplatin in estrogen-treated cells was significantly decreased by 5-aza-2 deoxycytidine pre-treatment, suggesting the role of estrogen-induced hypermethylation in enhanced sensitivity of these drugs in estrogen-exposed cells. In conclusion, results of this study demonstrate that sensitivity to chemotherapy depends on the levels of estrogen in breast cancer cells. Findings of this study will have clinical implications in selecting the type and dose of chemotherapy in breast cancer patients depending on the serum estrogen levels that varies in between pre- and post-menopausal age of the patients. Citation Format: Yu-Wei Chang, Kamaleshwar Singh. Elevated level of estrogen enhances chemotherapeutic efficacy potentially through epigenetic mechanism in human breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 5758. doi:10.1158/1538-7445.AM2017-5758

LncRNA H19 confers chemoresistance in ERα-positive breast cancer through epigenetic silencing of the pro-apoptotic gene BIK.

Breast cancer is a common malignancy in women. Acquisition of drug resistance is one of the main obstacles encountered in breast cancer therapy. Long non-coding RNA (lncRNA) has been demonstrated to play vital roles in both development and tumorigenesis. However, the relationship between lncRNAs and the development of chemoresistance is not well established. In the present study, the high expression of lncRNA H19 was identified as a powerful factor associated with paclitaxel (PTX) resistance in ERα-positive breast cancer cells, but not in ERα-negative breast cancer cells. LncRNA H19 attenuated cell apoptosis in response to PTX treatment by inhibiting transcription of pro-apoptotic genes BIK and NOXA. H19 was further confirmed to suppress the promoter activity of BIK by recruiting EZH2 and by trimethylating the histone H3 at lysine 27. Interestingly, our data showed that lncRNA H19 was one of the downstream target molecules of ERα. Altered ERα expression may therefore change H19 levels to modulate the apoptosis response to chemotherapy in breast cancer cells. Our data suggest that the ERα-H19-BIK signaling axis plays an important role in promoting chemoresistance.

Curcumin enhances poly(ADP-ribose) polymerase inhibitor sensitivity to chemotherapy in breast cancer cells

Poly(ADP-ribose) polymerase (PARP) inhibitor has shown promising responses in homologous recombination (HR) repair-deficient cancer cells. More specifically, targeting HR pathway in combination with PARP inhibitor has been an effective chemotherapy strategy by so far. Curcumin has been recognized as anticancer agents for several types of cancers. Here, we demonstrate that curcumin inhibits a critical step in HR pathway, Rad51 foci formation, and accumulates γ-H2AX levels in MDA-MB-231 breast cancer cells. Curcumin also directly reduces HR and induces cell death with cotreatment of PARP inhibitor in MDA-MB-231 breast cancer cells. Moreover, curcumin, when combined with ABT-888, could effectively delayed breast tumor formation in vivo. Our study indicates that cotreatment of curcumin and PARP inhibitor might be useful for the combination chemotherapy for aggressive breast cancer treatment as a natural bioactive compound.

Abstract 3496: Improvement of response to chemotherapy in breast cancer cells by the use of the non-oncologic drug minocycline

Abstract Introduction The majority of breast cancer patients receive (neo-) adjuvant chemotherapy. Although a high percentage of patients show good response - as shown by pathologic complete response - another high number of patients does not profit from chemotherapeutic treatments. Therefore, there is a high demand for improvement of chemotherapeutic treatments. It has been proposed that non-oncologic drugs, which are used in treatment of other diseases, might represent a valid novel therapeutic approach, as these drugs have already been tested for side effects, etc. Nonetheless, a dramatic breakthrough by using non-oncologic drugs as single treatment agents has not been published so far. However, we hypothesized that a combinatorial treatment using oncologic drugs as well as non-oncologic drugs might improve the response to classical cancer treating agents, e.g. chemotherapeutic agents. Recently, we could show a sensitization of triple negative breast cancer cells to chemotherapy by using the anti-androgenic drug dutasteride in combination with either cisplatinum as well as paclitaxel (von Wahlde et al., 2014). Currently, we deeply analyze the effect of another non-oncologic drug - minocycline - in the treatment of breast cancer cells. Minocycline has been described as a broad-spectrum tetracycline antibiotic. It has already been proposed that it might also improve chemotherapeutic treatments as well as radiation treatments (Sotomayor et al. 1992). However, an improvement of chemotherapy in breast cancer patients has not been described so far. Methods Breast cancer cells were treated with increasing concentrations of minocycline. Subsequently, cells were treated with minocycline in combination with different cytotoxic agents. Cell viability was measured using MTT assays. Molecular biological analyses were performed in order to dissect the mechanisms resulting in altered chemotherapeutic responses. Results When treated in the presence of minocycline alone, some breast cancer cells showed reduced viability only at high concentrations. The combinatorial treatment using minocycline plus cytotoxic agents however, greatly improved the response to the cytotoxic agents, as viabilitiy drastically decreased. Conclusion We conclude that the use of non-oncologic drugs might greatly improve the response to standard chemotherapeutic agents in the treatment of breast cancer. Thus, patients suffering from breast cancer might profit from a combinatorial application of both minocycline as well as standard chemotherapeutic agents. As minocycline targets several distinct cellular components, a deeply analysis is needed in order to evaluate the mechanisms underlying the improved response to cytotoxic agents. Citation Format: Christof Bernemann, Ludwig Kiesel. Improvement of response to chemotherapy in breast cancer cells by the use of the non-oncologic drug minocycline. [abstract]. In: Proceedings of the 106th Annual Meeting of the American Association for Cancer Research; 2015 Apr 18-22; Philadelphia, PA. Philadelphia (PA): AACR; Cancer Res 2015;75(15 Suppl):Abstract nr 3496. doi:10.1158/1538-7445.AM2015-3496

Abstract 1485: Snail activation of MAPK pathway may contributes to tumor insensitivity to tamoxifen chemotherapy in breast cancer cells.

Abstract Snail is a zinc finger transcriptional repressor that induces epithelial-mesenchymal transitions (EMT) and is expressed at high levels in tumors. Snail contributes to chemotherapy resistance in ovarian, liver, colorectal, and breast carcinomas by activating the MAPK/ERK1/2 (ERK1/2) pathway . ERK1/2 controls cell proliferation, survival, migration, and adhesion. However, a role for MAPK in Snail-mediated EMT in breast cancer is unclear. We hypothesized that Snail promotes EMT by decreasing cell adhesion and increasing cell migration through the MAPK pathway, resulting inresistance to Tamoxifen chemotherapy. Preliminary results suggest that breast cancer cells express variable levels of Snail that is higher than in normal MCF10A cells. We utilized MCF-7 breast adenocarcinoma cells transfected stably with empty Neo vector control (MCF-7 Neo) or constitutively active Snail cDNA (MCF-7 Snail). MCF-7 Neo and MCF-7 Snail have previously represented a breast cancer EMT model; we used this model to examine cell adhesion and cell migration. We injected these cells into female nude mice to examine tumor size. We also examined activation of MAPK pathway using phospo-ERK (p-ERK) antibodies in response to Snail overexpression and the effect of inhibiting this pathway with UO126 (MEK inhibitor, 20uM). Finally, we tested how Snail overexpression affects response to UO126 and/or Tamoxifen treatments using MTS cell proliferation assay. Our results showed that Snail overexpression led to decreased cell adhesion and increased cell migration on collagen and fibronectin in vitro, and increased tumorigenicity in vivo. Interestingly, immunofluorescent analysis revealed that activated ERK1/2 (p-ERK) had cytoplasmic localization in MCF-7 Neo, and exclusive nuclear localization in MCF-7 Snail. Inhibition of activated ERK1/2 with UO126 antagonized cell adhesion primarily in MCF-7 Neo cells, while it decreased cell migration primarily in MCF-7 Snail cells. This would suggest that cytoplasmic p-ERK may be important for cell adhesion while nuclear p-ERK may be important for cell migration. MCF-7 Neo proliferation was consistently higher than MCF-7 Snail indicating that Snail may not play a significant role in cell proliferation, but other EMT functions like migration and adhesion. Tamoxifen treatment did not affect MCF-7 Snail cells morphologically, but led to sickly-appearing MCF-7 Neo cells. Additionally, MCF-7 Snail cells treated with Tamoxifen proliferated at similar rates to control untreated cells but co-treatment with UO126 greatly inhibited cell proliferation. This suggests that antagonizing nuclear p-ERK may sensitize breast cancer cells to Tamoxifen therapy. In conclusion, our study shows that Snail activation of MAPK pathway specifically within the nucleus promotes resistance to Tamoxifen and future ERK1/2 inhibition within the nucleus may sensitize cells to chemotherapy. Citation Format: Bethany N. Smith, Peri Nagappan, Mahandranauth Chetram, LaTonia Taliaferro-Smith, Clayton Yates, Cimona Hinton, Valerie Odero-Marah. Snail activation of MAPK pathway may contributes to tumor insensitivity to tamoxifen chemotherapy in breast cancer cells. [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 1485. doi:10.1158/1538-7445.AM2013-1485

Up-Regulation of Kin17 Is Essential for Proliferation of Breast Cancer

BackgroundKin17 is ubiquitously expressed at low levels in human tissue and participates in DNA replication, DNA repair and cell cycle control. Breast cancer cells are characterized by enabling replicative immortality and accumulated DNA damage. However, whether kin17 contributes to breast carcinogenesis remains unknown.Methodology/Principal FindingsIn this study, we show for the first time that kin17 is an important molecule related to breast cancer. Our results show that kin17 expression was markedly increased in clinical breast tumors and was associated with tumor grade, Ki-67 expression, p53 mutation status and progesterone receptor expression, which were assessed in a clinicopathologic characteristics review. Knockdown of kin17 inhibited DNA replication and repair, blocked cell cycle progression and inhibited anchorage-independent growth, while increasing sensitivity to chemotherapy in breast cancer cells. Moreover, kin17 silencing decreased EGF-stimulated cell growth. Furthermore, overexpression of kin17 promoted DNA replication and cell proliferation in MCF-10A.Conclusions/SignificanceOur findings indicate that up-regulation of kin17 is strongly associated with cellular proliferation, DNA replication, DNA damage response and breast cancer development. The increased level of kin17 was not only a consequence of immortalization but also associated with tumorigenesis. Therefore, kin17 could be a novel therapeutic target for inhibiting cell growth in breast cancer.

Therapeutic Ultrasonic Microbubbles Carrying Paclitaxel and LyP-1 Peptide: Preparation, Characterization and Application to Ultrasound-Assisted Chemotherapy in Breast Cancer Cells

The aim of this work was to develop a novel targeted drug-loaded microbubble (MB) and to investigate its chemotherapy effect in vitro. Paclitaxel (PTX)-loaded lipid MBs were prepared by a mechanical vibration technique. The LyP-1, a breast tumor homing peptide, was coated onto the surface of PTX-loaded MBs through biotin-avidin linkage. The resulting targeted drug-loaded MBs were characterized and applied to ultrasound-assisted chemotherapy in breast cancer cells. Our results showed the ultrasonic MBs were able to achieve 43%–63% of drug encapsulation efficiency, depending on drug loading amount. The binding affinity assay indicated the attachment of targeted MBs to human MDA-MB-231 breast cancer cells was highly efficient and stable even with ultrasonic irradiation on. The cellular uptake efficiency of payload in targeted MBs was 3.71-, 4.95-, 7.43- and 7.66-fold higher than that of non-targeted MBs at the applied ultrasound time of 30, 60, 90 and 120 s, respectively. In addition, the cell proliferation inhibition assay showed the cell viability of targeted PTX-loaded MBs was significantly lower than that of non-targeted PTX-loaded MBs and non-targeted unloaded MBs when ultrasound was utilized. In conclusion, the study indicated the LyP-1-coated PTX-loaded MBs significantly increased the antitumor efficacy and can be used as a potential chemotherapy approach for ultrasound-assisted breast cancer treatment.(E-mail: hr.zheng@siat.ac.cn)

A role for the cancer-associated miR-106b~25 cluster in neuronal stem cells

A role for the cancer-associated miR-106b~25 cluster in neuronal stem cells

Scoring of senescence signalling in multiple human tumour gene expression datasets, identification of a correlation between senescence score and drug toxicity in the NCI60 panel and a pro-inflammatory signature correlating with survival advantage in peritoneal mesothelioma

BackgroundCellular senescence is a major barrier to tumour progression, though its role in pathogenesis of cancer and other diseases is poorly understood in vivo. Improved understanding of the degree to which latent senescence signalling persists in tumours might identify intervention strategies to provoke "accelerated senescence" responses as a therapeutic outcome. Senescence involves convergence of multiple pathways and requires ongoing dynamic signalling throughout its establishment and maintenance. Recent discovery of several new markers allows for an expression profiling approach to study specific senescence phenotypes in relevant tissue samples. We adopted a "senescence scoring" methodology based on expression profiles of multiple senescence markers to examine the degree to which signals of damage-associated or secretory senescence persist in various human tumours.ResultsWe first show that scoring captures differential induction of damage or inflammatory pathways in a series of public datasets involving radiotherapy of colon adenocarcinoma, chemotherapy of breast cancer cells, replicative senescence of mesenchymal stem cells, and progression of melanoma. We extended these results to investigate correlations between senescence score and growth inhibition in response to ~1500 compounds in the NCI60 panel. Scoring of our own mesenchymal tumour dataset highlighted differential expression of secretory signalling pathways between distinct subgroups of MPNST, liposarcomas and peritoneal mesothelioma. Furthermore, a pro-inflammatory signature yielded by hierarchical clustering of secretory markers showed prognostic significance in mesothelioma.ConclusionsWe find that "senescence scoring" accurately reports senescence signalling in a variety of situations where senescence would be expected to occur and highlights differential expression of damage associated and secretory senescence pathways in a context-dependent manner.

Synergistic antitumor efficacy of oncolytic adenovirus combined with chemotherapy

Chemotherapy is an effective means of treating breast cancer, and cancer-specific replicative adenovirus is also a promising antitumor agent in recent years. Our investigation aims to demonstrate that CNHK300 can mediate selective antitumor efficacy and produce synergistic cytotoxicity with chemotherapy on HER-2 over-expressing breast cancer. We engineered the telomerase-dependent replicative adenovirus CNHK300 by placing the E1A gene under the control of the human hTERT promoter. By analysis of E1A expression, we proved the fidelity of hTERT promoter in adenovirus genome and the selective expression of E1A in telomerase-positive breast cancer cells but not in normal fibroblast cells. By proliferation test, we further showed efficient replication of CNHK300 in breast cancer cells with apparently attenuated proliferation in normal fibroblast cells. Finally, we demonstrated by MTT methods that CNHK300 virus caused potent cytolysis and produced synergistic cytotoxicity with chemotherapy in breast cancer cells with attenuated cytotoxicity on normal cells. In this virus, the E1A gene is successfully placed under the control of the human hTERT promoter. CNHK300 virus replicated as efficiently as the wild-type adenovirus and caused intensive cell killing in HER-2 over-expressing breast cancer cells in vitro. In contrast, telomerase-negative normal fibroblast cells, which expressed no hTERT activity, were not able to support CNHK300 replication. Combined treatment of CNHK300 with paclitaxel improved cytotoxicity on cancer cells. We conclude that CNHK300 can produce selective antitumor efficacy and enhance the in vitro response of chemotherapy on HER-2 overexpressing breast cancer.