Target For Breast Cancer Therapy Research Articles

LinTT1 peptide-functionalized liposomes for targeted breast cancer therapy

Breast cancer, with around 2 million new cases in 2019, is the second most common cancer worldwide and the second leading cause of cancer death among females. The aim of this work is to prepare a targeting nanoparticle through the conjugation of LinTT1 peptide, a specific molecule targeting p32 protein overexpressed by breast cancer and cancer associated cells, on liposomes’ surface. This approach increases the cytotoxic effects of doxorubicin (DOX) and sorafenib (SRF) co-loaded in therapeutic liposomes on both 2D and 3D breast cancer cellular models. The liposome functionalization leads to a higher interaction with 3D breast cancer spheroids than bare ones. Moreover, interaction studies between LinTT1-functionalized liposomes and M2 primary human macrophages show an internalization of 50% of the total nanovesicles that interact with these cells, while the other 50% results only associated to cell surface. This finding suggests the possibility to use the amount of associated liposomes to enrich the hypoxic tumor area, exploiting the ability of M2 macrophages to accumulate in the central core of tumor mass. These promising results highlight the potential use of DOX and SRF co-loaded LinTT1-functionalized liposomes as nanomedicines for the treatment of breast cancer, especially in triple negative cancer cells.

MiR‑653‑5p suppresses the growth and migration of breast cancer cells by targeting MAPK6.

Breast cancer is the worldwide leading cause of cancer-related deaths among women. Increasing evidence has demonstrated that microRNAs (miRNAs) play critical roles in the carcinogenesis and progression of breast cancer. miR-653-5p was previously reported to be involved in cell proliferation and apoptosis. However, the role of miR-653-5p in the progression of breast cancer has not been studied. In the present study, it was found that overexpression of miR-653-5p significantly inhibited the proliferation, migration and invasion of breast cancer cells in vitro. Moreover, overexpression of miR-653-5p promoted cell apoptosis in breast cancer by regulating the Bcl-2/Bax axis and caspase-9 activation. Additionally, the epithelial-mesenchymal transition and activation of the Akt/mammalian target of rapamycin signaling pathway were also inhibited by miR-653-5p. Furthermore, the data demonstrated that miR-653-5p directly targeted mitogen-activated protein kinase 6 (MAPK6) and negatively regulated its expression in breast cancer cells. Upregulation of MAPK6 could overcome the inhibitory effects of miR-653-5p on cell proliferation and migration in breast cancer. In conclusion, this study suggested that miR-653-5p functions as a tumor suppressor by targeting MAPK6 in the progression of breast cancer, and it may be a potential target for breast cancer therapy.

Long non-coding RNA VCAN-AS1 promotes the malignant behaviors of breast cancer by regulating the miR-106a-5p-mediated STAT3/HIF-1α pathway

ABSTRACT An accumulating number of studies have found that long noncoding RNAs (lncRNAs) participate in breast cancer (BC) development. LncRNA VCAN-AS1, a novel lncRNA, has been confirmed to regulate the progression of gastric cancer, while its role in BC is elusive. Here, our results illustrate that VCAN-AS1 is overexpressed in BC tissues and cells, while miR-106a-5p was downregulated and negatively correlated with VCAN-AS1. In addition, high VCAN-AS1 expression and low miR-106a-5p expression were closely correlated with poor overall survival in BC patients. Functional experiments confirmed that VCAN-AS1 overexpression notably accelerated BC cell proliferation, migration, invasion, and epithelial–mesenchymal transition (EMT) and enhanced tumor cell growth while also suppressing cell apoptosis. However, overexpression of miR-106a-5p had the opposite effects. In addition, rescue experiments confirmed that overexpression of VCAN-AS1 inhibited the tumor-suppressive effects mediated by miR-106a-5p. Mechanistically, through bioinformatics analysis, we found that VCAN-AS1 functions as a competitive endogenous RNA (ceRNA) of miR-106a-5p, which targets the 3ʹ untranslated region (UTR) of signal transducer and activator of transcription 3 (STAT3). Further experiments indicated that miR-106a-5p downregulated the STAT3/hypoxia-inducible factor-1alpha (HIF-1α) pathway, while activating the STAT3 pathway reversed miR-106a-5p-mediated antitumor effects. Collectively, our data suggest that VCAN-AS1 is upregulated in breast cancer and promotes its progression by regulating the miR-106a-5p-mediated STAT3/HIF-1α pathway. This study provides a new target for BC therapy.

CCL16 maintains stem cell-like properties in breast cancer by activating CCR2/GSK3β/β-catenin/OCT4 axis.

Rationale: Considerable evidence suggests that breast cancer metastasis and recurrence occur due to emergence of cancer stem cells (CSCs). In our previous study, we designed a high-throughput siRNA screening platform that identifies inflammation genes involved in the regulation of cancer cell stemness. We reported that CCL16 protein decreases OCT4 expression and reduces the ALDH+ subpopulation. However, the mechanism by which CCL16 maintains stem cell-like properties remains unclear.Methods: Tissue microarrays were used to evaluate CCL16 expression. Cancer stemness assays were performed in CCL16 knockdown and overexpressing cells in vitro and in a xenograft model in vivo. Human phosphokinase array, immunofluorescence and chromatin immunoprecipitation assays were performed to explore the underlying mechanism.Results: We report that CCL16 was overexpressed in breast tumors and significantly correlated with clinical progression. We found that silencing CCL16 in MDA-MB-231 and BT549 cells diminished CSC properties including ALDH+ subpopulation, side population, chemo-resistance, and sphere formation. Furthermore, mice bearing CCL16-silenced MDA-MB-231 xenografts had lower tumorigenic frequency and developed smaller tumors. Exploration of the underlying mechanism found that CCL16 selects CCR2 to activate p-AKT/GSK3β signaling and facilitate β-catenin nuclear translocation. Further, CCL16 binds to the OCT4 promoter and promotes OCT4 expression. In addition, shRNAs targeting CCR2 and XAV939 targeting β-catenin abolished CCL16-mediated cancer stemness. Upstream, IL10 mediates STAT3 activation, which binds to the CCL16 promoter and enhances its expression. The STAT3-targeted inhibitor Stattic suppressed CCL16 expression in vitro and restrained tumor progression in vivo.Conclusions: We identified a potential CSC regulator and suggest a novel mechanism for how CCL16 governs cancer cell stemness. We propose that CCL16 could be an effective target for breast cancer therapy.

Genetically Engineered Bacterial Protein Nanoparticles for Targeted Cancer Therapy.

PurposeCancer treatment still faces big challenges in the clinic, which is raising concerns over the world. In this study, we report the novel strategy of combing bacteriotherapy with high-intensity focused ultrasound (HIFU) therapy for more efficient breast cancer treatment.MethodsThe acoustic reporter gene (ARG) was genetically engineered to be expressed successfully in Escherichia coli (E. coli) to produce the protein nanoparticles-gas vesicles (GVs). Ultrasound was utilized to visualize the GVs in E. coli. In addition, it was injected intravenously for targeted breast cancer therapy by combing the bacteriotherapy with HIFU therapy.ResultsARG expressed in E. coli can be visualized in vitro and in vivo by ultrasound. After intravenous injection, E. coli containing GVs could specifically target the tumor site, colonize consecutively in the tumor microenvironment, and it could obviously inhibit tumor growth. Meanwhile, E. coli which contained GVs could synergize HIFU therapy efficiently both in vitro and in vivo as the cavitation nuclei. Furthermore, the tumor inhibition rate in the combination therapy group could be high up to 87% compared with that in the control group.ConclusionOur novel strategy of combing bacteriotherapy with HIFU therapy can treat breast cancers more effectively than the monotherapies, so it can be seen as a promising strategy.

Development and evaluation of polycaprolactone based docetaxel nanoparticle formulation for targeted breast cancer therapy

The present study describes the preparation, characterization, and applications of newly developed polymeric poly-ɛ-caprolactone (PCL)/pluronic F108 nanoparticles, loaded with anticancer drug, and near infrared (NIR) dye for assessing the localization in the breast cancer model system. Docetaxel and NIR dye, “1,1′-dioctadecyl- 3,3,3′,3′- tetramethylindotricarbocyanine iodide (DiR)” loaded, poly-ɛ-caprolactone (PCL)/pluronic F108–based nanoparticles were formulated by nanoprecipitation method. This formulation was then characterized using various physicochemical methods including size distribution, zeta potential, surface morphology, drug entrapment efficiency, loading capacity, differential scanning calorimetry, in vitro release, and kinetics are performed. In vitro cell proliferative studies of human breast cancer BT-474 cells were carried out to evaluate the anticancer efficacy of the nanoparticles. The role of pluronic F108 was also evaluated in cell uptake of the nanoparticles. Drug- and NIR dye–loaded nanoparticles localization at tumor site were studied using noninvasive infrared dye imaging. The optimized nanoparticle formulation had a particle size of 100–300 nm, poly dispersity index of 0.156 and zeta potential of − 7.37 mV ± 4.93 mV. Drug release from the nanoparticle system followed Higuchi kinetics, suggesting diffusion mediated drug release. DSC studies suggest that the drug is either in amorphous or disordered crystalline state in the nanoparticle formulation. The increased accumulation of the PCL/ F108 nanoparticles in vivo suggests its potential as a superior targeted drug delivery system.

Surface functionalisation of poly-APO-b-polyol ester cross-linked copolymers as core\u2013shell nanoparticles for targeted breast cancer therapy

Polymeric nanoparticles (NPs) are commonly used as nanocarriers for drug delivery, whereby their sizes can be altered for a more efficient delivery of therapeutic active agents with better efficacy. In this work, cross-linked copolymers acted as core–shell NPs from acrylated palm olein (APO) with polyol ester were synthesized via gamma radiation-induced reversible addition-fragmentation chain transfer (RAFT) polymerisation. The particle diameter of the copolymerised poly(APO-b-polyol ester) core–shell NPs was found to be less than 300 nm, have a low molecular weight (MW) of around 24 kDa, and showed a controlled MW distribution of a narrow polydispersity index (PDI) of 1.01. These properties were particularly crucial for further use in designing targeted NPs, with inclusion of peptide for the targeted delivery of paclitaxel. Moreover, the characterisation of the synthesised NPs using Fourier Transform-Infrared (FTIR) and Neutron Magnetic Resonance (NMR) analyses confirmed the possession of biodegradable hydrolysed ester in its chemical structures. Therefore, it can be concluded that the synthesised NPs produced may potentially contribute to better development of a nano-structured drug delivery system for breast cancer therapy.

Heat Shock Protein 27 Enhances SUMOylation of Heat Shock Protein B8 to Accelerate the Progression of Breast Cancer

Heat shock proteins (HSPs) are emerging as valuable potential molecular targets in breast cancer therapy owing to their diverse functions in cancer cells. This study investigated the potential role of heat shock protein 27 (HSP27, also known as HSPB1) in breast cancer through heat shock protein B8 (HSPB8). The correlation between HSP27 and HSPB8 was identified by using co-immunoprecipitation, immunoprecipitation, and SUMOylation assays. Through gain- and loss-of-function approaches in MCF-7 cells, the effect of HSP27 on HSPB8 expression, SUMOylation level, and protein stability of HSPB8, as well as on cell proliferation, migration, and stemness, was elucidated. A mouse xenograft model of breast cancer cells was established to verify the function of HSP27 invivo. Results indicate that HSP27 and HSPB8 were highly expressed in breast cancer tissues and MCF-7 cells. HSP27 was also found to induce the SUMOylation of HSPB8 at the 106 locus and subsequently increased its protein stability, which resulted in accelerated proliferation, migration, and stemness of breast cancer cells invitro along with increased tumor metastasis of breast cancer invivo. However, these results could bereversed by the knockdown of HSPB8. Overall, HSP27 induces SUMOylation of HSPB8 to promote HSPB8 expression, thereby endorsing proliferation and metastasis of breast cancer cells. This study mayprovide insight for the development of new targets for breast cancer.

Notch3 Knockout Suppresses Mouse Mammary Gland Development and Inhibits the Proliferation of 4T1 Murine Mammary Carcinoma Cells via CCL2/CCR4 Axis.

Our previous study found that Notch3 knockout mice exhibit defects in mammary gland development. To elucidate the underlying mechanism, tissue samples were subjected to RNA-seq, GO, and KEGG enrichment analyses and qRT-PCR validation. Of enriched pathways, chemokine signaling pathway and cytokine–cytokine receptor interaction were noticed in both Notch3wt/wt/Notch3wt/– and Notch3wt/wt/Notch3–/– mice, in which the expression of chemokine ligand 2 (CCL2) was sharply reduced in Notch3wt/– and Notch3–/– mammary gland tissues. The Mouse ENCODE transcriptome data reveal that the mammary gland fat pad exhibits a high CCL2, CCR2, and CCR4 expression, indicating that these molecules play important roles during mammary gland development. Specifically, defective mammary glands in Notch3 knockout mice could be partially rescued by CCL2 overexpression lentivirus through intraductal injection. An in vitro study showed that CCL2 overexpression promoted the proliferation, migration, and cancerous acinar formation of 4T1 cells, which could rescue the defective migration of 4T1 cells caused by Notch3 knockdown. We also found that Notch3 transcriptionally regulated the expression of CCL2 in a classical pattern. Our findings illustrated that Notch3-regulating CCL2/CCR4 axis should be an important signaling pathway for mammary gland development and should be a candidate target for breast cancer therapy.

IN SILICO IDENTIFICATION OF TARGET PALINDROMIC GENES AS POTENTIAL DRUG TARGETS IN BREAST CANCER THERAPY

Objectives: Diabetes is increasingly recognized as a serious, worldwide public health concern. By early identifying those at risk to develop diabetes and if confirmed to be at pre-diabetes stage adequate care provided for them through lifestyle interventions or even hypoglycemic medications if necessary, thus delaying or preventing their progression to diabetic status. The study aims at assessing the risk of developing type 2 diabetes mellitus (T2DM) among healthy non-diabetic Sudanese in Khartoum city. Breast cancer (BC) is the most common cancer worldwide prevalent among women with more than one million cases and is second only to lung cancer.
 Methods: The identification of the sequences based on the unique tetramers GCAC, GTCA were selected from experimental work. The16 base pair DNA regulatory sequences of which the motifs area part of containing these motif in genes implicated in cancer CAGE1 (AAGCTGTCATTA), BRCA1(GACTGAGTCAA), ABCB1(CTCTAAGTCAT), ABCB5 (GATATGTTAAAGC) and ABI1(CTTCTGGGAA) were then selected as novel putative targets in breast cancer therapy based on their selectivity on the BC oncogenes which are not found in the normal human genome 1-23 and the sex chromosomes X and Y were obtained via computational analysis.
 Results: The single copy base pairs which will be potential drug targets as anticancer drugs were finally obtained as CTGTTATGACTGAGTCAA, CAGE1 with the 17 base pairs CATAAAAGC TGTCATTA and ABCB1 TTGCCAA CTCTAAGT CAT.
 Conclusion: It is Possible that the in silico discovery of putative anti breast cancer targets of importance in the genome.
 Peer Review History: 
 Received 18 July 2020; Revised 25 September; Accepted 12 October, Available online 15 November 2020
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Bisecting GlcNAc modification diminishes the pro-metastatic functions of small extracellular vesicles from breast cancer cells.

Small extracellular vesicles (sEVs) are enriched in glycoconjugates and display specific glycosignatures. Aberrant expression of surface glycoconjugates is closely correlated with cancer progression and metastasis. The essential functions of glycoconjugates in sEVs are poorly understood. In this study, we observed significantly reduced levels of bisecting GlcNAc in breast cancer. Introduction of bisecting GlcNAc into breast cancer cells altered the bisecting GlcNAc status on sEVs, and sEVs with diverse bisecting GlcNAc showed differing functions on recipient cells. Carcinogenesis and metastasis of recipient cells were enhanced by sEVs with low bisecting GlcNAc, and the pro‐metastatic functions of sEVs was diminished by high bisecting GlcNAc modification. We further identified vesicular integrin β1 as a target protein bearing bisecting GlcNAc. Metastasis of recipient cells was strongly suppressed by high bisecting GlcNAc levels on vesicular β1. Our findings demonstrate the important roles of glycoconjugates on sEVs. Modification of sEV glycosylation may contribute to development of novel targets in breast cancer therapy.

Ectopic Expression of the Meiotic Protein SYCP2 in Breast Cancer Promotes Homologous Recombination and Endows Broad Resistance to DNA Repair-Targeted Drugs

Drugs targeting the DNA damage response (DDR) pathway are widely used in cancer therapy, but resistance to these drugs remains a major clinical challenge. Here, we show that SYCP2, a component of the meiotic synaptonemal complex, is ectopically expressed in breast cancer and associates with broad resistance to DDR-targeted drugs including Cisplatin, inhibitors for PARP, topoisomerase II and topoisomerase I. SYCP2 overexpression correlates with poor prognosis in breast cancer patients and with decreased survival in a clinical trial of antibody-conjugated topoisomerase I inhibitor. SYCP2 overexpression is sufficient to enhance homologous recombination (HR) and confer DDR-targeted drugresistance. Mechanistically, SYCP2 responds to DNA double strand breaks via its lysine/arginine residues and promotes RAD51 localization to DNA breaks by interacting with RAD51. SYCP2 promotes HR independently of BRCA1, suggesting that SYCP2 is a BRCA-independent determinant of DNA damage sensitivity. Thus, SYCP2, which enhances HR, is potentially a biomarker for breast cancer diagnosis, a predictor of DDR-targeted drug response, a prognostic marker for patient outcome, and a target in breast cancer therapy.

Methylation-Mediated Silencing of MicroRNA-497 Promotes Breast Cancer Progression Through Up-Regulation of Mucin1.

BackgroundPotential anti-tumor effects of microRNA-497 (miR-497) have been highlighted in various malignancies including breast cancer. However, little is known about the function of miR-497 and its putative target mucin1 (MUC1) in breast cancer. The present study explored how miR-497 regulates breast cancer progression in a MUC1-dependent manner.MethodsExpression of miR-497 and MUC1 was determined in breast cancer tissues and cells. Methylation specific polymerase chain reaction was used to measure the methylation status of CpG islands of miR-497 promoter, while chromatin immunoprecipitation assay was used to detect recruitment of methyltransferase to the promoter region of miR-497. Alteration in expression of miR-497 (overexpression) and MUC1 (up- and down-regulation) was performed to examine their roles in breast cancer biology in vitro and in vivo. The binding affinity between miR-497 and MUC1 was investigated through a bioinformatics database and dual luciferase reporter gene assay.ResultsMiR-497 was down-regulated and MUC1 was up-regulated in breast cancer tissues and cell lines. Besides, methylation induced a down-regulation of miR-497 in breast cancer. The bioinformatics analysis and dual luciferase reporter gene assay indicated that miR-497 targeted MUC1. Overexpression of miR-497 inhibited breast cancer cell proliferation and invasion and promoted the apoptosis of breast cancer cells by down-regulating MUC1. The inhibitory action of miR-497 on tumor growth was validated in vivo.ConclusionIn conclusion, miR-497 down-regulated MUC1 expression and subsequently suppressed breast cancer progression, highlighting miR-497 to be a potential biomarker and therapeutic target for breast cancer therapy.

Transcriptional repression of p21 by EIF1AX promotes the proliferation of breast cancer cells

ObjectiveDysregulation of the cell cycle is associated with the progression of malignant cancer, but its precise functional contribution is unknown.Materials and MethodsThe expression of EIF1AX in breast cancer tissues was detected by qRT‐PCR and immunohistochemistry staining. Colony formation and tumour xenograft assays were used to examine the tumorigenesis‐associated function of EIF1AX in vitro and in vivo. RNA‐Seq analysis was used to select the downstream target genes of EIF1AX. Flow cytometry, ChIP and luciferase assays were used to investigate the molecular mechanisms by which EIF1AX regulates p21 in breast cancer cells.ResultsEIF1AX promoted breast cancer cell proliferation by promoting the G1/S cell cycle transition. A mechanistic investigation showed that EIF1AX inhibited the expression of p21, which is an essential cell cycle regulator. We identified that the transcriptional regulation of p21 by EIF1AX was p53‐independent. Clinically, EIF1AX levels were significantly elevated in breast cancer tissues, and the high level of EIF1AX was associated with lower survival rates in breast cancer patients.ConclusionsOur results imply that EIF1AX may play a key role in the incidence and promotion of breast cancer and may, thus, serve as a valuable target for breast cancer therapy.

Features of the Proteasome Pool in Spontaneously Occurring Malignant Tumors of the Mammary Gland in Mice

The aim of this work is to investigate the features of the proteasome pool in malignant tumors of mammary glands on a unique model of inbred BLRB/BYRB mice characterized by a high probability of spontaneous development of this type of cancer. It was found that the proteasome pool of mammary glands was relatively stable and it did not change in mice of various physiological states: normal females of different age and a tumor carrier. However, with the formation of malignant tumors, this stability is violated, and the proteasome pool undergoes complex changes. In general, it increases in the number of proteolytic subparticles. At the same time, its chymotrypsin-like activity increases disproportionately more intensively, which indicates additional mechanisms for its regulation. These mechanisms include the detected increased expression of activators PA28αβ and 19S RC as well as changes in the subunit composition of proteasomes due to increased expression of the immune subunits LMP2 and LMP7. The amount of each of the studied components in the proteasome pool increased in the tumor in different ways. The most significant increase was observed in the amount of two components, 19S RC activator and LMP2 subunit, which indicates the prospects of their use as targets for breast cancer therapy. However, we must not forget that these components are also important for the vital functions of normal cells. Therefore, when creating new drugs, we should simultaneously develop methods for their targeted delivery to the tumor or other ways of safe use.

Synergistic Interactions of 5-Fluorouracil with Inhibitors of Protein Kinase CK2 Correlate with p38 MAPK Activation and FAK Inhibition in the Triple-Negative Breast Cancer Cell Line.

Background: The combination effect of 5-fluorouracil (5-FU) with either CX-4945 or a new inhibitor of protein kinase CK2, namely 14B (4,5,6,7-tetrabromo-1-(3-bromopropyl)-2-methyl-1H-benzimidazole), on the viability of MCF-7 and triple-negative MDA-MB-231 breast cancer cell lines was studied. Methods: Combination index (CI) values were determined using an MTT-based assay and the Chou-Talalay model. The effect of the tested drug combinations on pro-apoptotic properties and cell cycle progression was examined using flow cytometry. The activation of FAK, p38 MAPK, and ERK1/2 kinases and the expression of selected pro-apoptotic markers in MDA-MB-231 cell line after the combined treatment were evaluated by the western blot method. Confocal microscopy was used to examine actin network in MDA-MB-231. Results: Our results showed that a synergistic effect (CI < 1) occurred in MDA-MB-231 after treatment with both combinations of 5-FU with 14B or CX-4945, whereas the combination of 5-FU and 14B evoked an antagonistic effect in MCF-7. We conclude that the synergistic interactions (CI < 1) observed for both the combinations of 5-FU and 14B or CX-4945 in MDA-MB-231 correlated with an activation of p38 MAPK, inhibition of FAK, increased expression of apoptogenic markers, prolongation of S-phase of cell cycle, and destabilization of actin network. Conclusions: The obtained results support the recent observation that CK2 inhibitors can improve 5-FU-based anticancer therapy and FAK kinase can be an attractive molecular target in breast cancer therapy.

Abstract 5276: Secretory pathway calcium ATPase 2 (SPCA2) promotes cell survival and chemoresistance in receptor positive breast cancer cells

Abstract Introduction: Dysregulation of the Ca2+ toolkit has profound consequences for tumor growth and metastasis, raising hopes for novel avenues of therapeutic intervention. The Secretory Pathway Ca2+-ATPase Isoform 2 (SPCA2) has a dual function in sequestering Ca2+ and Mn2+ into secretory stores as well as eliciting their entry into cells by activating plasma membrane ion channels. We have previously showed that SPCA2 is implicated in breast cancer progression, microcalcifications, epithelial-mesenchymal transition, and metastasis. Methods and Results: High SPCA2 expression was associated with poor overall survival in receptor positive breast cancer patients (n=548, P =8.7e-0.6; KM Plotter). Depletion of SPCA2 (SPCA2 KD) in MCF-7 cells significantly reduced cell proliferation (P &amp;lt; 0.05). Analysis of the cell cycle (PI staining, Flow cytometry) revealed a significant increase (P &amp;lt; 0.05) in the number of cells in the G0/G1 phase, and significant increase in apoptosis (via TUNEL assay) (P &amp;lt; 0.05) in SPCA2 KD cells compared to control. Microarray analysis showed the p53 pathway is the most significantly upregulated pathway (P &amp;lt; 0.05) in SPCA2 KD cells compared to control. P53 knockout abrogated SPCA2 mediated cell cycle arrest and apoptosis. Depletion of SPCA2 increased reactive oxygen species (ROS, measured by DCFDA dye and MitoSox Red using flow cytometry) leading to DNA damage (confocal microscopy), and activation of ATM/ATR pathway (Immunoblotting, P &amp;lt; 0.05). As a consequence, SPCA2 KD cells showed specific hypersensitivity to DNA damaging agents used in breast cancer therapy (carboplatin, radiation, and doxorubicin) (determined by MTT assay) (P &amp;lt; 0.05). Thus SPCA2 is a novel molecular target in breast cancer therapy. Curcumin is currently being evaluated in clinical trials of breast cancer. We show that curcumin causes dose-dependence inhibition of SPCA2 expression (P &amp;lt; 0.05) in multiple receptor-positive cell lines, and that forced overexpression of SPCA2 decreased curcumin cytotoxicity. Interestingly, we did not observe these results with SPCA1, the housekeeping SPCA isoform, revealing isoform-specific function of Golgi calcium pumps in breast cancer subtypes. Conclusion: These novel findings point to a causal link between SPCA2, breast cancer progression, and chemoresistance to DNA damaging agents. Decrease of SPCA2 expression by curcumin may have therapeutic potential in treating receptor positive breast cancer. Citation Format: Monish Ram Makena, Donna Dang, Allatah Mekile, Phillip Buckhaults, Rajini Rao. Secretory pathway calcium ATPase 2 (SPCA2) promotes cell survival and chemoresistance in receptor positive breast cancer cells [abstract]. In: Proceedings of the Annual Meeting of the American Association for Cancer Research 2020; 2020 Apr 27-28 and Jun 22-24. Philadelphia (PA): AACR; Cancer Res 2020;80(16 Suppl):Abstract nr 5276.

Natural polysaccharide derived carbon dot based in situ facile green synthesis of silver nanoparticles: Synergistic effect on breast cancer

Over the decades, several nanoparticles have been developed for biomedical applications, still facile green synthesis derived nanoparticles showed tremendous attraction due to avoid of toxic solvent, ease of synthesis and low cost. Here, facile one pot in situ green synthesis is reported to develop silver nanoparticles with the aid of natural polysaccharide presented in sweet lemon peel waste derived carbon dot (CD) acted as a reducing and stabilizing agent at room temperature. The synthesis of CD and CD based silver nanoparticles (CD@AgNPs) was characterized by FTIR, UV–vis spectroscopy, fluorescence spectrophotometer, XRD and TEM. CD@AgNPs exhibited excellent antimicrobial activity against E. coli at very low concentration of 5.0 μg/ml. Interestingly, CD showed selective cytotoxicity against MCF7 breast cancer cells with the IC50 of 10 μg/ml while CD@AgNPs demonstrated synergistic effect on cytotoxicity. It is found that the cells death of MCF7 cells mainly occurred through the up-regulation of intracellular reactive oxygen species (ROS). Therefore, the synthesized CD@AgNPs may show an efficient anticancer agent for targeted breast cancer therapy in future.

Long Intergenic Non-Coding RNA LINC00922 Aggravates the Malignant Phenotype of Breast Cancer by Regulating the microRNA-424-5p/BDNF Axis.

PurposeLong intergenic non-coding RNA 922 (LINC00922) plays a critical role in the progression of lung cancer. In this study, we aimed to quantify LINC00922 expression in breast cancer and determine its influence on the malignant behavior of breast cancer cells in vitro and in vivo. We also investigated the mechanism by which LINC00922 affects the progression of breast cancer.Materials and MethodsReverse transcription-quantitative polymerase chain reaction was performed to quantify LINC00922 expression in breast cancer tissues and cell lines. The cell counting kit-8 assay, flow cytometry, Transwell migration and invasion assays, and tumor model assays were performed to determine the effects of LINC00922 deficiency on breast cancer cell proliferation, apoptosis, migration and invasion in vitro, and tumor growth in vivo, respectively. Furthermore, bioinformatics analysis was performed to predict the potential target microRNA of LINC00922. The prediction was further evaluated using luciferase reporter and RNA immunoprecipitation assays.ResultsLINC00922 was clearly overexpressed in breast cancer tissues and cell lines. LINC00922 depletion restricted breast cancer cell proliferation, migration, and invasion but induced cell apoptosis in vitro. Additionally, its knockdown evidently repressed tumor growth of breast cancer cells in vivo. Mechanistically, LINC00922 was demonstrated to serve as a molecular sponge for miR-424-5p in breast cancer cells. Furthermore, brain-derived neurotrophic factor (BDNF) was verified as a direct target of miR-424-5p in breast cancer cells, and BDNF expression was found to be positively regulated by LINC00922 through sponging miR-425-5p. Rescue experiments further revealed that the influences on breast cancer cell proliferation, apoptosis, migration, and invasion induced by LINC00922 silencing were abrogated by increasing the output of the miR-424-5p/BDNF axis.ConclusionThe LINC00922/miR-424-5p/BDNF pathway is implicated in the acceleration of the malignant behavior of breast cancer cells. These findings suggest that this pathway is a promising novel molecular target in breast cancer therapy.

Extracellular ATP promotes breast cancer invasion and chemoresistance via SOX9 signaling.

Our previous research demonstrated that extracellular adenosine 5'-triphosphate (ATP) could promote breast cancer cell invasion. However, the impact of extracellular ATP on chemoresistance and the mechanisms behind ATP pro-invasion and pro-chemoresistance remain unclear. Here we aimed to determine the molecules or signaling pathways involved. cDNA microarray was performed to identify the differentially expressed genes before and after ATP treatment. As a result, Sex-determining region Y-box 9 (SOX9) was up-regulated after ATP treatment in breast cancer cells. In vitro invasion and migration assays demonstrated that knocking down SOX9 attenuated ATP-driven invasive capability. Mass spectrometry and co-IP revealed that SOX9 interacted with Janus kinase 1 (JAK1). Afterward, IL-6-JAK1-STAT3 signaling was demonstrated to promote SOX9 expression and invasion following ATP treatment. Notably, ATP-IL-6-SOX9 signaling was shown to stimulate chemoresistance in breast cancer cells. ChIP assays identified some potential SOX9 target genes, among which carcinoembryonic antigen-related cell adhesion molecule 5/6 (CEACAM5/6) was demonstrated to mediate ATP pro-invasive function, while ATP-binding cassette subfamily B member 1 (ABCB1) and ATP-binding cassette subfamily G member 2 (ABCG2) mediated ATP-driven chemoresistance. In addition, SOX9-knockdown and apyrase (an ATP hydrolase)-treated MDA-MB-231 cells illustrated decreased tumor growth and enhanced drug sensitivity in nude mice. In vitro spheroid formation assays also proved the significance of ATP-SOX9 in mediating chemoresistance. Moreover, molecules involved in ATP-SOX9 signaling were up-regulated in human breast carcinoma specimens and were associated with poor prognosis. Altogether, SOX9 signaling is vital in ATP-driven invasion and chemoresistance, which may serve as a potential target for breast cancer therapies.