MDA-MB231 Cell Lines Research Articles

Synthesis and antiproliferative activity of 6BrCaQ-TPP conjugates for targeting the mitochondrial heat shock protein TRAP1

A series of 6BrCaQ-Cn-TPP conjugates 3a-f and 5 was designed and synthesized as a novel class of TRAP1 inhibitors. Compound 3a displayed an excellent anti-proliferative activity with mean GI50 values at a nanomolar level in a diverse set of human cancer cells (GI50 = 0.008–0.30 μM) including MDA-MB231, HT-29, HCT-116, K562, and PC-3 cancer cell lines. Moreover, the best lead compound 6BrCaQ-C10-TPP induces a significant mitochondrial membrane disturbance combined to a regulation of HSP and partner protein levels as a first evidence that his mechanism of action involves the TRAP-1 mitochondrial Hsp90 machinery.

Abstract P127: Mitochondrial matrix protease ClpP agonists suppress breast cancer stem cell function by downregulating multiple stem cell regulatory mechanisms

Abstract Background: We previously reported that small molecule ONC201 induces mitochondrial structural and functional damage, leading to death in breast cancer cells. Subsequent studies demonstrated that ONC201 and the related analogs TR compounds are agonists of mitochondrial caseinolytic protease P (ClpP), an essential protein for maintenance of mitochondrial protein homeostasis. Recent studies have shown that cancer stem cells (CSCs) preferentially use mitochondrial oxidative metabolism for energy production. Here, we report that ClpP agonists inhibit breast CSCs by unique mechanisms targeting pathways vital to maintain CSC function. Methods: ONC201 and other ClpP agonists (TR-57, 65), other mitochondria-targeting drugs, such as oligomycin, metformin, CPI-613 were used. MDA-MB231 cell line was used as a primary in vitro model system. CLPP knockout (KO) cells were generated by CRISPR/Cas9 technology. Seahorse XF analyzer was used for cellular respiration analysis. Luminescence-based assays were used for cell viability and metabolism assays. Protein expression was examined by Western blotting. Aldefluor assay and SORE6 (OCT4/SOX2 response element)-reporter gene were used to monitor CSC fraction. Mammosphere formation assay was used to evaluate CSC function in vitro. In vivo limiting dilution analysis was used to evaluate tumor initiation capability of cells injected into mammary fat pad of athymic nude female mice. Results: Seahorse XF analyzer showed that mammospheres are more dependent on OxPhos than glycolysis compared with cells grown in 2D, supporting the hypothesis that breast CSCs rely on OxPhos. ClpP agonists reduced the CSC fraction in both Aldefluor and SORE6 reporter assays. ClpP agonists inhibited mammosphere formation in CLPP WT, but not in CLPP KO cells, demonstrating the on-target effects on CSC function. In in vivo assays, tumor formation was significantly (p<0.001) inhibited in the ClpP agonist-treated group compared with the control group, and the effect was CLPP-dependent. Altogether, these findings support that ClpP agonists inhibit CSC in breast cancers. We found that ClpP agonists downregulate multiple pathways and proteins critical for CSC maintenance including mevalonate pathway, HIF1a, EPAS1, YAP, and Myc. We also observed that other mitochondria targeting drugs such as oligomycin, metformin downregulate these signaling pathways and proteins to some extent. Importantly, however, ClpP agonists showed significantly greater impact in mammosphere formation and cell growth assays, compared with other mitochondria-targeting drugs. Further studies revealed that ClpP agonists uniquely deplete NAD+/NADH and promote reactive oxygen species, both of which are shown as key factors to maintain pluripotency of stem cells. Moreover, ClpP agonists uniquely inhibited enzymes involved with glutamine catabolism and proline biosynthesis, vital to amino acids and nucleotide synthesis. Conclusion: ClpP agonists inhibit cell growth and tumor initiation in breast cancer cells by targeting multiple pathways essential to maintain CSC function. Citation Format: Yoshimi E. Greer, Lidia Hernandez, Donna Voeller, Raj Chari, Binwu Tang, Christina M. Annunziata, Sam Gilbert, Lalage Wakefield, Edwin Iwanowicz, Lee M. Graves, Stanley Lipkowitz. Mitochondrial matrix protease ClpP agonists suppress breast cancer stem cell function by downregulating multiple stem cell regulatory mechanisms [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2021 Oct 7-10. Philadelphia (PA): AACR; Mol Cancer Ther 2021;20(12 Suppl):Abstract nr P127.

Yerba Mate Modulates Tumor Cells Functions Involved in Metastasis in Breast Cancer Models.

Breast cancer (BC) is the most frequent cancer in women and tumor metastasis is a major cause of cancer-related deaths. Our aim was to evaluate anti-metastatic properties of yerba mate extract (YMe) in BC models. 4T1, F3II, MCF-7, and MDA-MB231 cell lines were used to perform in vitro assays. The F3II syngeneic mammary carcinoma model in BALB/c mice was used to evaluate tumor progression, BC metastasis and survival. Cells were inoculated subcutaneously into the flank for the heterotopic model and into the mammary fat pad for the orthotopic model. YMe was administered p.o. in a dose of 1.6 g/kg/day. In vitro YMe inhibited cell proliferation and reduced tumor cell adhesion, migration and invasion. These biological effects were cell-line dependent. In vivo YMe reduced tumor metastasis and increased mice survival in both models. Our preclinical results suggest that YMe could modulate tumor progression and metastasis in BC models.

Alteration of miR-362-5p and miR-454-3p expression elicits diverse responses in breast cancer cell lines.

The heterogeneity of breast tumors presents a challenge in disease management, necessitating an understanding of the molecular mechanisms driving breast tumorigenesis. Aberrant expression of microRNAs is known to promote tumor growth and progression. Our previous RNA-sequencing dataset revealed the upregulation of miR-362-5p and miR-454-3p in breast tumors. We investigated potential role of miR-362-5p and miR-454-3p in breast cancer using MDAMB231 and MCF7 cell lines. The expression of miR-362-5p and miR-454-3p were altered in MCF7 and MDAMB231 using mimics and inhibitors. The effect on cell viability, cell cycle progression and migration was assessed using Alamar blue assay, flow cytometry and wound healing assay. Further, the expression of potential target genes were measured using real-time PCR. Our results indicated that an increased expression of miR-362-5p promoted cell growth and survival in MCF7, but decreased cell migration. In contrast, miR-362-5p overexpression reduced cancer cell growth, survival and migration in MDAMB231. Overexpression of miR-454-3p was oncogenic in both cell lines but suppressed migration in the aggressive cell line MDAMB231. Two microRNAs, miR-362-5p and miR-454-3p, were evaluated for functional activity in breast cancer cell lines and they showed increased proliferative signals and tumorigenic properties.

Synthesis, characterization, crystal structure, anti-cancer activities, and computational study of a novel thiophenylchromane

• ((thiophen-2-ylmethyl)amino)ethylidene)chromane-2,4-dione was synthesized. • The theoretical and experimental data confirmed each other. • The structure of ligand was studied with crystallography. • The ligand displayed moderate anticancer properties. ((thiophen-2-ylmethyl)amino)ethylidene)chromane-2,4-dione ( 3 ) was synthesized using 1:1 ratio of 3-acetyl-4-hydroxycoumarin and thiophen-2-ylmethanamine. The main goal of this study was to determine the crystalline structure of compound 3 , mainly to investigate if the dominant chemical form is imine or enamine. Therefore, it was synthesized and characterized with FT-IR, 1 H NMR, 13 C NMR, mass spectroscopy, and elemental analysis. The obtained data were compared with theoretical FT-IR, 1 H NMR, 13 C NMR calculated with density functional theory (DFT), which confirmed that there is a good correlation between them. The single-crystal X-ray structure of compound 3 was also solved using the crystallography data which confirmed that compound 3 is an enamine rather than an imine. Compound 3 showed significant inhibitory effect against MCF-7, HepG2, U87-MG, SKOV3, MDA-MB231, BEAS-2B, and L929 cell lines (IC 50 values < 50 µg/mL). In particular, the IC 50 values of compound 3 against HepG2 (cancer cell line) and BEAS-2B (normal cell line) were 26.04 and 35.63 µg/mL, respectively.

Stereoselective Synthesis of the Di-Spirooxindole Analogs Based Oxindole and Cyclohexanone Moieties as Potential Anticancer Agents.

A new series of di-spirooxindole analogs, engrafted with oxindole and cyclohexanone moieties, were synthesized. Initially, azomethine ylides were generated via reaction of the substituted isatins 3a–f (isatin, 3a, 6-chloroisatin, 3b, 5-fluoroisatin, 3c, 5-nitroisatin, 3d, 5-methoxyisatin, 3e, and 5-methylisatin, 3f, and (2S)-octahydro-1H-indole-2-carboxylic acid 2, in situ azomethine ylides reacted with the cyclohexanone based-chalcone 1a–f to afford the target di-spirooxindole compounds 4a–n. This one-pot method provided diverse structurally complex molecules, with biologically relevant spirocycles in a good yields. All synthesized di-spirooxindole analogs, engrafted with oxindole and cyclohexanone moieties, were evaluated for their anticancer activity against four cancer cell lines, including prostate PC3, cervical HeLa, and breast (MCF-7, and MDA-MB231) cancer cell lines. The cytotoxicity of these di-spirooxindole analogs was also examined against human fibroblast BJ cell lines, and they appeared to be non-cytotoxic. Compound 4b was identified as the most active member of this series against prostate cancer cell line PC3 (IC50 = 3.7 ± 1.0 µM). The cyclohexanone engrafted di-spirooxindole analogs 4a and 4l (IC50 = 7.1 ± 0.2, and 7.2 ± 0.5 µM, respectively) were active against HeLa cancer cells, whereas NO2 substituted isatin ring and meta-fluoro-substituted (2E,6E)-2,6-dibenzylidenecyclohexanone containing 4i (IC50 = 7.63 ± 0.08 µM) appeared to be a promising agent against the triple negative breast cancer MDA-MB231 cell line. To explore the plausible mechanism of anticancer activity of di-spirooxindole analogs, molecular docking studies were investigated which suggested that spirooxindole analogs potentially inhibit the activity of MDM2.

Atorvastatin Modulates the Efficacy of Electroporation and Calcium Electrochemotherapy

Electroporation is influenced by the features of the targeted cell membranes, e.g., the cholesterol content and the surface tension of the membrane. The latter is eventually affected by the organization of actin fibers. Atorvastatin is a statin known to influence both the cholesterol content and the organization of actin. This work analyzes the effects of the latter on the efficacy of electroporation of cancer cells. In addition, herein, electroporation was combined with calcium chloride (CaEP) to assess as well the effects of the statin on the efficacy of electrochemotherapy. Cholesterol-rich cell lines MDA-MB231, DU 145, and A375 underwent (1) 48 h preincubation or (2) direct treatment with 50 nM atorvastatin. We studied the impact of the statin on cholesterol and actin fiber organization and analyzed the cells’ membrane permeability. The viability of cells subjected to PEF (pulsed electric field) treatments and CaEP with 5 mM CaCl2 was examined. Finally, to assess the safety of the therapy, we analyzed the N-and E-cadherin localization using confocal laser microscopy. The results of our investigation revealed that depending on the cell line, atorvastatin preincubation decreases the total cholesterol in the steroidogenic cells and induces reorganization of actin nearby the cell membrane. Under low voltage PEFs, actin reorganization is responsible for the increase in the electroporation threshold. However, when subject to high voltage PEF, the lipid composition of the cell membrane becomes the regulatory factor. Namely, preincubation with atorvastatin reduces the cytotoxic effect of low voltage pulses and enhances the cytotoxicity and cellular changes induced by high voltage pulses. The study confirms that the surface tension regulates of membrane permeability under low voltage PEF treatment. Accordingly, to reduce the unfavorable effects of preincubation with atorvastatin, electroporation of steroidogenic cells should be performed at high voltage and combined with a calcium supply.

Discovery of triaromatic flexible agents bearing 1,2,3-Triazole with selective and potent anti-breast cancer activity and CDK9 inhibition supported by molecular dynamics

This study reports an efficient and convenient click synthesis of novel series of chromene scaffold linked to 1,2,3 triazole ring and terminal lipophilic fragments. Structures of all newly synthesized compounds were well characterized by IR, 1H NMR, 13C NMR and elemental analyses. In vitro MTT cytotoxic screening was performed using staurosporine as a reference drug against three different types: aggressive and invasive human breast cancer cell line (MDA-MB 231), Michigan cancer foundation-7 (MCF-7) and human colorectal carcinoma cell line (HCT116). These screening data showed considerable anticancer activity for these newly synthesized compounds compared to reference staurosporine drug with high degree of cell line selectivity and excellent activity with micromolar (µM) half maximal inhibitory concentration (IC50) values against tumor cells. In addition, Cyclin-Dependent Kinase1 and 9 (CDK1 and 9) assays were performed for the most active compounds to get more details about their mechanism of action. In order to assess and explain their binding affinities, molecular docking simulation was studied against CDK9 site. The results obtained from molecular docking study and those obtained from cytotoxic screening and enzyme inhibition were correlated. One of the most prominent analogs is 34 that showed high selective cytotoxicity profile against single breast cancer cell line MCF-7 and MDA-MB 231 with IC50 3.4 µM and 1.4 uM respectively. Molecular dynamics (MD) simulation of the CDK9 complex by Desmond revealed stability during 100 ns with RMSD of CDK9 complex converged at 2.1 Å after 20 ns. During MD, the interaction fractions confirmed multiple interactions of 34 with Cys106, a crucial residue for inhibition of CDK9 activity. A novel 34 triazole compound was introduced for drug design works as potent and selective hit for treatment of breast cancers after processing of optimization steps.

Synthesis, crystal structure, DFT, docking and biological activity studies of (NZ,N’Z)-3,3’-(piperazine-1,4-diyl)bis(N-(-4-methyl benzylidene)propane-1-amine)

The title compound (NZ,N’Z)-3,3’-(piperazine-1,4-diyl)bis(N-(-4-methyl benzylidene)propane-1-amine) (PMP) was synthesized by reacting N,N′-bis(3-aminopropyl)piperazine and 4- methyl benzaldehyde using microwave energy. The formed compound is characterized using FTIR, 1H and 13C NMR, UV–visible and elemental analysis techniques. Single crystal X-ray diffraction confirms that the title compound crystallizes in a monoclinic crystal system with space group of P21/c. The unusual C–H…π interaction facilitate the crystal packing proved by the Density Functional Theory (DFT) and Hirshfeld surface analysis. The PMP showed an excellent result against Enterococcus Faecalis with the value of 3.125 μg/ml. The antioxidant behavior of PMP showed strong antioxidant property. The in silico docking studies on breast cancer cell BRCA1 protein confirms that the PMP showed excellent binding affinity value of −6.80 kcal/mol. The lipophilicity of the molecule is high due to the non polar nature of the PMP. The in vitro anticancer studies on the breast cancer cell line MDA MB-231 showed promising results.

Formulation and performance evaluation of polymeric mixed micelles encapsulated with baicalein for breast cancer treatment

The present study is aimed to formulate baicalein-loaded mixed micelles to enhance the solubility and oral bioavailability. Baicalein encapsulated D-α-tocopherol polyethylene glycol 1000 succinate (TPGS) and pluronic F127 (F127) combined micelles were prepared and investigated for anticancer effect. The optimized formulation contains 25.04 ± 0.24 nm mean particle size of micelles with a zeta potential value of −4.01 ± 0.5 mV. The calculated entrapment efficiency percentage of baicalein within the micellar structure was 83.43 ± 0.13% and the in vitro release of baicalein from micelles displayed a sustained release profile at pH 7.4. The incorporation of baicalein within micelles core was also confirmed by FTIR analysis of formulation, which hardly represents the characteristic peak of baicalein, indicating successful entrapment of the drug. In vitro cell culture experiments revealed baicalein-loaded micelles significantly enhanced cellular uptake and cytotoxicity against MDAMB-231 cell lines in comparison to free baicalein. Additionally, as compared to free baicalein, baicalein micelles demonstrated greater apoptosis-inducing potential while the results of the cell cycle study exhibited arrest of cells at the G0/G1 phase of the cell cycle. Results of ROS (reactive oxygen species) and MMP (mitochondrial membrane potential) assay revealed the ROS-dependent mitochondrial-mediated apoptosis pathway utilized by developed formulation to inhibit cell proliferation. Thus, the developed nano micelles can serve as a potent carrier system for baicalein against breast cancer.

Vitamin D3/phospholipid complex decorated caseinate nanomicelles for targeted delivery of synergistic combination therapy in breast cancer

Targeted delivery of cytotoxic drugs has shown great potential in cancer therapy. In this light, vitamin D3 (vit.D3)-coated micelles were fabricated to encapsulate the cytotoxic drug; etoposide (ETP). Sodium caseinate micelles were first utilized to encapsulate vit.D3 and ETP within their hydrophobic core, then drug-loaded micelles were further decorated with an envelope of vit.D3/ phospholipid complex to enhance the active targeting potency of fabricated micelles via exploiting vit.D3 receptors (VDRs) overexpressed on the outer surface of breast cancer cells. In vitro cytotoxicity studies showed that fabricated micelles exhibited improved anticancer effect on MDA MB-231 and MCF-7 human breast cancer cell lines in comparison to free vit.D3 + ETP without any significant toxicity on normal human lung fibroblast (Wi-38) cells. In vivo biodistribution and efficacy studies in Ehrlich ascites tumor animal model revealed that fabricated micelles manifested improved accumulation in tumor tissue due to active targeting potential of vit.D3 without any remarkable toxicity. More importantly, fabricated micelles resulted in enhanced tumor apoptosis, reduced angiogenesis, invasion and autophagy, besides a decline in the tumor expression levels of both miR-21 and miR-192. Therefore, vit.D3/ETP micelles could serve as a favorable actively targeted anticancer delivery system having a superior effect over the free combination.

Bioactivity Studies of Hesperidin and XAV939.

The present work aimed to evaluate the reactivity of natural bioflavonoid hesperidin (HSP) and synthetically derived XAV939 (XAV) against human hepatocellular carcinoma (HepG2), human breast cancer (MDA-MB231) cancer cell lines, and related molecular and pathological profiles. Data recorded revealed that the cytotoxic potential of the tested products was found to be cell type- and concentration-dependent. The half-maximal inhibitory concentration (IC50) value of the HSP-XAV mixture against MDA-MB231 was significantly decreased in the case of using the HSP-XAV mixture against the HepG2 cell line. Also, there was a significant upregulation of the phosphotumor suppressor protein gene (P53) and proapoptotic genes such as B-cell lymphoma-associated X-protein (Bax, CK, and Caspase-3), while antiapoptotic gene B-cell lymphoma (Bcl-2) was significantly downregulated compared with the untreated cell control. The cell cycle analysis demonstrated that DNA accumulation was detected mainly during the G2/M phase of the cell cycle accompanied with the elevated reactive oxygen species level in the treatment of HepG2 and MDA-MB231 cell lines by the HSP-XAV mixture, more significantly than that in the case of cell control. Finally, our finding suggests that both HSP and XAV939 and their mixture may offer an alternative in human liver and breast cancer therapy.

The Cytotoxic effect of an Ethanol extract of Momordica Charantia, Kuguacin-J and Cisplatin on healthy MCF-10A and MCF-7 and MDAMB-231 breast cancer cell lines employing In Vitro assays

Traditional medicines, derived from plants, could present alternative treatment strategy for cancer therapy. One such plant is Momordica charantia (MC) which possesses anti-carcinogenic properties. This study investigated the anticancer effect of an ethanol extract of MC fruit, Kuguacin-J (K-J), an isolated compound from the leaves of MC and cisplatin, either alone or combination on healthy MCF-10A mammary cells and compared with breast cancer MCF-7 and MDAMB-231 cell lines. Cell viability was tested using 8 μg/mL and 80 μg/mL doses of MC extract, K-J and cisplatin individually or combined for 24 and 48 hours. Caspase-3- activity was measured in MCF-7 and MDA-MB-231 cells using established methods. The results revealed that MC extract and K-J had no effect on healthy MCF-10A cell viability as compared to cisplatin which induced dose and time-dependent cell death. Similarly, treatment of MCF-7 cells with cisplatin induced cell death at high concentration at both the time points, while MC extract and K-J only induce MCF-7 cell death at high dose after 48 hours only. During combination therapy, both doses of cisplatin enhanced MCF-7 cell death when combined with MC extract or K-J after 24 and 48 hours. In MDAMB-231 cells, the three drugs, either alone or combined, evoked significant cell death at both the doses and time points. All three drugs, at high dose, elicited significant increase in caspase-3- activity in MCF-7 and MDA-MB-231 cells as compared to untreated cells. The results revealed that either MC extract or K-J alone or combined with cisplatin, can elicit significant increase in cell death and caspase–3-activity in MCF-7 and MDA-MB-231cells as compared to untreated cells.

Synthesis, self-assembly and drug release study of a new dual-responsive biocompatible block copolymer containing phenylalanine derivative

Stimuli-responsive polymers as drug delivery vehicles have generated remarkable interest among polymer researchers during the last decade. In the present work, we report the synthesis of a new water soluble pH- and thermo-responsive biocompatible block copolymer containing phenylalanine derivatives. The block copolymer formed micelle-like self-assembled nanoparticles above critical aggregation concentration, as confirmed from fluorescence spectroscopy, DLS, and AFM studies. The self-assembly behavior was dependent on the pH and temperature of the aqueous media. These self-assembled micellar nanoparticles were capable of encapsulating hydrophobic drugs as demonstrated by the significantly higher loading capacity value of Doxorubicin (DOX) compared to commonly reported values in the literature. The release of DOX from the nanoparticles was favored at lower pH and higher temperature, a condition prevalent in cancer cells. Biocompatibility of the block copolymer and the effectiveness of the nanoparticles in potential cancer therapy were established by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) studies using non-cancerous murine fibroblasts L929 cells and breast cancer cell line MDA MB 231 at 37 °C and 42 °C. The cytotoxicity of DOX loaded polymer nanoparticles was found to be more effective at 42 °C compared to 37 °C. Thus, these micellar nanoparticles hold promise in drug delivery application in cancer therapy.

Abstract 2836: Effect of autophagy inhibition on epithelial mesenchymal transition in breast cancer cell lines

Abstract The aim of our work is to evaluate potential undesirable effects of autophagy inhibition in breast cancer subtypes which are not sensitive to the inhibition of autophagy. Worldwide, BC is the most frequent cancer in women. Despite recent advances in diagnosis, molecular stratification and targeted therapy, BC is still the leading cause of cancer-related death in women. Thus, it is a public health issue that must be attended. In cancer, autophagy has a pro-tumorigenic role that helps tumor cells survive metabolic stress and growth factor deprivation, hypoxia, maintain tumor initiating cells, confer therapy resistance and modulate epithelial mesenchymal transition (EMT). Because tumor cells benefit from autophagy, it has been proposed that autophagy inhibition could be beneficial for cancer treatment. Nowadays, there are clinical trials where autophagy is being inhibited with promising results that encourage this approach. However, in these clinical trials, cancer types are not been stratified and autophagy is being inhibited in many solid tumor types. In this regard, there is also in vitro evidence in which autophagy inhibition in some cancer types induces EMT, which in the clinic could be detrimental for patients. This highlights the urgency for stratifying patients that will benefit the most from autophagy inhibition. In this work, autophagy inhibition in MCF7 ER+ cell line increased secretion, inflammation and EMT related pathways suggesting induction of malignancy. Autophagy inhibition induced changes in cell morphology in ER+ breast cancer cell lines (MCF7 and T47D) when evaluated by aspect ratio estimation changing from a cobblestone -like epithelial morphology to a fibroblast-like morphology. No changes in cell morphology were found in MCF10A and MDAMB231 cell lines. Changes in morphology were accompanied by a decrease in E-cadherin protein levels suggesting induction of EMT. Our results suggest that CQ treatment in ER+ BC cells could induce a malignant process related to EMT. Thus, ER+ BC patients may not benefit from autophagy inhibition. Nowadays, there are clinical trials where autophagy is being inhibited and no subtype stratification is being done, so we encourage to stratify patients to determine who will be benefited the most from autophagy inhibition and who will not. Citation Format: Guadalupe Rojas, Nidia Pazos, Paola Maycotte. Effect of autophagy inhibition on epithelial mesenchymal transition in breast cancer cell lines [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 2836.

Abstract 589: CCR5 upregulation in two subtypes of tumor associated circulating cells predict worse prognosis in metastatic breast cancer

Abstract Background: CCR5 is a motility chemokine receptor implicated in tumor progression, whose activation and endocytosis may identify highly aggressive breast cancer (BC) subtypes likely to spread via the circulatory system. We first studied the activation and endocytosis of CCR5 in response to its ligand CCL5 (RANTES) in the model BC cell line MDA-MB231. We then screened two types of circulating tumor-associated cells (TACs) with known negative clinical outcomes, 1) circulating tumor cells (CTCs) and 2) cancer-associated macrophage-like (CAMLs) cells, to evaluate CCR5 upregulation in relation to disease progression in metastatic breast cancer (mBC). Methods: MB231 cells were used to visualize CCR5 activation within the cell's surface and intracellular space using an anti-CCR5 antibody after stimulation with RANTES. MB231 cells were stained with LAMP-1A to verify co-localization of CCR5 and RANTES to endosomes. Anonymized peripheral blood samples from (n=54) mBC patients were obtained in accordance with local IRB regulations and with informed consent. TACs were isolated using a low-flow CellSieve Microfiltration system and stained for Cytokeratin, CD45, and CCR5. CCR5 expression signal and localization were evaluated on all TACs via fluorescence microscopy. Results: CCR5 in MB231 cells appeared as ~1μm clusters known as “CCR5 pools”, which can be found on the cell's surface, within the cytoplasm, and in the nuclear space. CCR5 pools were upregulated in the presence of RANTES, which appears to relate to endocytosis and nuclear translocation. Within the TACs of mBCs, we found similar patterns of CCR5 pooling with 70% of patients (n=38) having CCR5+ CAMLs and 41% (n=22) having CCR5+ CTCs. It was found that higher numbers of CCR5 pools (≥10pools/cell) were correlated to a 2-fold increase in both CTCs and CAMLs in circulation. In the analysis of outcome data, it was determined that patients having ≥10 CCR5 pools on their CAMLs was a highly significant predictor of worse progression free survival (PFS) and overall survival (OS) (PFS HR=4.8, CI 95% 1.9-11.6, p=0.0015) and (OS HR=3.6, CI 95% 1.3-10.0, p=0.0331). In CTCs ≥10 pools/cell was not a significant predictor for worse PFS and OS. However, ≥5 CCR5 pools/cell significantly predicted for worse PFS but not OS (PFS HR=2.9, CI 95% 1.2-7.4, p=0.0418 and OS HR=3.3, CI 95% 1.1-9.3, p= 0.0539). Conclusion: We observed the activation and endocytosis of CCR5 pools using RANTES in MD-MB231 cell lines, and then demonstrated that this upregulated motility pathway appears to be conserved in migratory cells in mBC patients. Further, this upregulation of CCR5 appears to correlate with worse clinical outcomes, which may provide an explanation for how tumor-associated cells move into circulation and acquire metastatic potential. Citation Format: Ashvathi Raghavakaimal, Massimo Cristofanilli, Cha-Mei Tang, R. K. Alpaugh, Kirby P. Gardener, Saranya Chumsri, Daniel L. Adams. CCR5 upregulation in two subtypes of tumor associated circulating cells predict worse prognosis in metastatic breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2021; 2021 Apr 10-15 and May 17-21. Philadelphia (PA): AACR; Cancer Res 2021;81(13_Suppl):Abstract nr 589.

HER3 PET Imaging Identifies Dynamic Changes in HER3 in Response to HER2 Inhibition with Lapatinib.

Standard therapy for HER2+ breast cancers includes HER2 inhibition. While HER2 inhibitors have significantly improved therapeutic outcomes, many patients remain resistant to therapy. An important intrinsic resistance mechanism to HER2 inhibition in some breast cancers is dynamic upregulation of HER3. Increase in HER3 expression that occurs in response to HER2 inhibition allows for continued growth signaling through HER2/HER3 heterodimers, promoting tumor escape. We hypothesized that a non-invasive method to image changes in HER3 expression would be valuable to identify those breast cancers that dynamically upregulate HER3 in response to HER2 inhibition. We further hypothesized that this imaging method could identify those tumors that would benefit by additional HER3 knockdown. In a panel of HER2+ breast cancer cell lines treated with the HER2 inhibitor lapatinib, we evaluate changes in HER3 expression and viability. Mouse HER2+ breast cancer models treated with lapatinib were imaged with a peptide-based HER3-specific PET imaging agent [68Ga]HER3P1 to assess for dynamic changes in tumoral HER3 expression and uptake confirmed by biodistribution. Subsequently, HER2+ cell lines were treated with the HER2 inhibitor lapatinib as well HER3-specific siRNA to assess for changes in viability and correlate with HER3 expression upregulation. For all statistical comparisons, P<0.05 was considered statistically significant. Lapatinib treatment of a panel of HER2+ breast cancer cell lines increased HER3 expression in the lapatinib-resistant cell line MDA-MB 453 but not the lapatinib-resistant cell-line HCC-1569. Evaluation of [68Ga]HER3P1 uptake in mice implanted with the HER2+ breast cancer cell lines MDA-MB453 or HCC-1569 prior to and after treatment with lapatinib demonstrated a significant increase in MDA-MB453 tumors only, consistent with in vitro findings. The additional knockdown of HER3 increased therapeutic efficacy of lapatinib only in MDA-MB453 cells, but not in HCC-1569 cells. HER3 PET imaging can be used to visualize dynamic changes in HER3 expression that occur in HER2+ breast cancers with HER2 inhibitor treatment and identify those likely to benefit by the addition of combination HER3 and HER2 inhibition.

SERCA Inhibition as a Potential Therapeutic Target for Breast Cancer

Chemotherapy is both a palliative treatment for many cancers and adjuvant treatment before, during, or after local treatment (surgery and/or radiation therapy) in single or combination regimens. Despite current treatments, approximately 1 in 39 women (3%) still die from breast cancer. A major complication with systemic therapy is drug resistance which limits the efficacy of clinical chemotherapy. Hence, current research aims to uncover novel targets for breast cancer therapy. Various studies have shown altered calcium signaling in breast cancer cells, therefore, calcium modulators may be potential therapeutic targets. Studies have also shown that Thapsigargin (TG) and cyclopiazonic acid (CPZ), two potent and specific inhibitors of the sarcoplasmic reticulum (SR) Ca2+-ATPase (SERCA), can impair cancer cell growth. However, TG and CPZ also impair non-malignant cells, which results in significant toxicity, thus preventing use in chemotherapy. Using spectrometry UV-visible measurements to assess calcium loading and ATPase activity in SR microsomes, our lab has found that various drugs which display cell protective effects in ischemia also inhibit SERCA. They include novel benzothiazepines (BZTs; K201, CGP37157, PH00095) and have shown to inhibit SERCA in a calcium dependent mechanism. They decreased SR uptake when cytosolic Ca2+ levels ([Ca2+]c) are low, similar to competitive inhibition of Ca2+ uptake, which produces mild store depletion. Contrarily, TG and CPZ block Ca2+ uptake at all [Ca2+]c and largely deplete SR stores. Using various SERCA inhibitors, we sought out to determine their effects on breast cancer cell lines of different subtypes. MTS assay studies show that TG and CPZ significantly reduce cell viability in MCF7 and MCF10A cell lines while having no significant effects on triple negative breast cancer (TNBC) cell line MDAMB231. Preliminary studies also show no significant effect by TG on BT20 cells, another TNBC cell line. BZT K201 also significantly reduced cell viability in MCF7 cells but not MDAMB231. Immunoblot shows MCF7 cells have significantly higher SERCA2 expression than MDAMB231. We observe no significant differences in plasma membrane calcium channel ATPase (PMCA) protein expression. Preliminary RT-PCR studies estimate MCF7 cells have a higher fold change in SERCA genes. Thus, targeting SERCA may serve as a potential therapeutic target for breast cancer. Here, we find that SERCA inhibitors TG, CPZ, and BZT K201 reduce cell viability in MCF7 cells. Still, these studies indicate that SERCA inhibition may only be efficacious in certain breast cancer cell types which do not express a TNBC phenotype. TNBC cell lines (MDAMB231, BT20) are not significantly affected by SERCA inhibition, which may be due to higher dependence for signaling on plasmalemma calcium channels and transporters. Additional studies are required to confirm the expression profiles of calcium transporters among cell lines, including those in the plasmalemma (PMCA, calcium channels), which may help to understand if alternative sources of Ca2+ for intracellular signaling make TNBC cell lines more resistant to SERCA inhibitors.

The growth of the MDA‐MB‐468, but not the MCF‐7 breast cancer cell line, is inhibited by (‐)‐catechin hydrate

Polyphenols are a group of natural antioxidants found in plants. Flavonoids are a subclass of polyphenols that include catechins. Epigallocatechine-3-gallate (EGCG), a type of catechin found in green tea, reduces the inflammation of breast cancer cells. Breast cancer is the second most common cancer in women worldwide, with an estimated 1.7 million new cases and 0.5 million cancer deaths in 2012. Some studies have suggested that consumption of green tea might play a preventive role in breast carcinogenesis. Multiple studies have investigated the effect of EGCG on the growth of breast cancer cells, but fewer experiments have investigated how exposure to (-)-catechin hydrate can affect the growth of breast cancer cell lines MDA-MB 468 and MCF-7. Here, we determine growth of these cell lines using the 3-(4,5-Dimethylthiazol -2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. We exposed the cells to 500μM concentration of (-)-catechin hydrate. We measure the percentage of live cells after 24 and 48 hours and compare it to controls. We found that this catechin has a small effect on the growth of both cell lines after 24 hours of 500μM (-)-catechin hydrate exposure, with 87-92% cell growth. After 48 hours, almost no change was observed in MCF-7 cells (86%) but MDA-MB-468 cells growth declined to 40%. While further experiments are needed, our initial findings suggest that (-)-catechin hydrate can affect the growth of triple negative breast cancer cells such as MDA-MB-468 more than the growth of receptor positive cells such as MCF-7. In our future experiments, we will investigate the mechanisms underlying this difference.

Cytotoxicity, in vivo toxicity, and chemical composition of the hexane extract of Plectranthus amboinicus (Lour.) Spreng.

Cancer is a universal health issue, and many anticancer therapeutic drugs have been isolated from natural products. This study analyzed the cytotoxic and apoptotic activity of Plectranthus amboinicus leaf hexane (PALH) extract in MDA-MB-231 (median inhibitory concentration [IC50] = 39.26 μg/mL) and MCF7 (IC50 = 89.05 μg/mL) breast cancer cell lines. Cells appeared rounded and shrunken, indicating morphological changes due to apoptosis induction. The primary constituent of PALH was phenol, 5-methyl-2-(1-methylethyl) (44%). PALH extract treatment increased the percentage of late apoptotic cells in the MDA-MB231 cell line (58% ± 1.5% at 200 μg/mL) compared to the control group, as evidenced by the activated caspase-3 and caspase-7 identified and captured by fluorescence microscopy. The relative migration rate in MDA-MB-231 cells treated with 10 μg/mL of PALH extract for 48 h was significantly lower compared to the control group. Analysis of acute (2000 mg/kg/BW) and subacute (250 and 500 mg/kg/BW) toxicity of PALH extract in mice showed no mortality or adverse effects in the kidney and liver histology compared to the control group. PALH extract can be considered nontoxic as it does not cause any adverse changes and so can be proposed as a potential breast anticancer agent.