MDA-MB231 Cells Research Articles

Persianolide-A, an eudesmanolide-type sesquiterpene lactone from Artemisia kopetdaghensis, induces apoptosis by regulating ERK signaling pathways.

Herbal components, particularly sesquiterpenes, are progressively recognized as a crucial resource for developing effective therapeutic agents for breast cancer. In this study, the effect of a sesquiterpene lactone known as 8-O-dihydroxy-11a,13-dihydroeudesma-4(15)-en-12,6a-olide (persianolide- A) was examined in breast cancer cell lines. MDA-MB-231 and MCF-7 cancer cells were grown in DMEM solution with 10% FBS. Then, an MTT assay was performed to evaluate cell viability. Apoptosis was detected by annexin-PI staining. A caspase 3/7 activity assay kit was used to assess the activity of caspase-3 and caspase-7. Protein expression of Bcl-2, Bax, and p-ERK1/2 was determined by western blotting. This study showed that the IC50 values of the persianolide-A for MCF-7 and MDA-MB- 468 cells are 34.76 and 54.48 μM, respectively. In addition, persianolide-A showed a significant increase in apoptosis in both MDAMB-231 and MCF-7 breast cancer cell lines. Persianolide-A significantly increased the expression of the pro-apoptotic protein Bax and decreased the expression of the anti-apoptotic protein Bcl-2. Also, presinolide-A treatment led to a substantial increase in caspase activity with a ratio of 3/7 in both MCF- 7 and MDA-MB-231 cancer cells. In addition, the study showed that persianolide-A decreased the expression of p-ERK1/2 protein. The results of this study suggest that persianolide-A, sourced from Artemisia kopetdaghensis, induces cell apoptosis in breast cancer cell types. The molecular mechanisms could be implicated in the modulation of the ERK1/2 signaling pathway.

Moringin, an isothiocyanate modulates multiple cellular signalling molecules in breast cancer cells

Prohibitin (PHB) is a pleiotropic molecule with a variety of known functions and subcellular locations. PHB's function in breast cancer is poorly understood. Herein, we report that PHB is expressed in cancer types of diverse origin including breast cancer. The cancer patients with changes in PHB were reported to have significantly reduced ‘overall survival’ in comparison to the cases without alterations in PHB. The expression of PHB was increased by H2O2 and also by Moringin (MG), which is an isothiocyanate derived from the seeds of Moringa oleifera. MG interacted with PHB, DRP1, and SLP2 and inhibited the growth of MCF-7 and MDAMB-231 cells. The isothiocyanate triggered apoptosis in breast cancer cells as revealed by AO/PI assay, phosphatidylserine externalization, cell cycle analysis and DAPI staining. MG induced proapoptotic proteins expression such as cytochrome c, p53, and cleaved caspase-7. Further, cell survival proteins such as survivin, Bcl-2, and Bcl-xL were suppressed. A depolarization of membrane potential suggested that the apoptosis was triggered through mitochondria. The isothiocyanate suppressed the cancer cell migration and interacted with NF-κB subunits. MG suppressed p65 nuclear translocation induced by TNF-α. The reactive oxygen species generation was also induced by the isothiocyanate in breast cancer cells. MG also modulated the expression of lncRNAs. Collectively, the functions of PHB in breast cancer growth is evident from this study. The activities of MG against breast cancer might result from its ability to modulate multiple cancer-related targets.

The procoagulant signature of cancer cells drives fibrin network formation in tumor microenvironment and impacts its quality. Implications in cancer cell migration and the resistance to anticancer agents

IntroductionCancer cells induce hypercoagulability in the tumoral microenvironment by expressing Tissue Factor (TF). We aimed to study the impact of the procoagulant signature of cancer cells on the quality and structure of fibrin network. We also studied the impact of fibrin clot shield (FCS) on the efficiency of anticancer agents and the migration of cancer cells. Materials and methodsPancreatic cancer cells BXPC3 and breast cancer cells MDA-MB231 and MCF7, were cultured in the presence of normal Platelet Poor Plasma (PPP), diluted 10 % in conditioning media. Their potential to induce thrombin generation and their fibrinolytic activity were assessed. The structure of fibrin network was analyzed with Scanning Electron Microscopy (SEM). Cancer cells' mobility with fibrin clot and their interactions with fibrin were observed. Cancer cells were treated with paclitaxel (PTX) or 4-hydroxy-tamoxifen (4OHTam) in the presence or absence of FCS. ResultsCancer cells, in presence of PPP, induced fibrin network formation. High TF-expressing cancer cells (BXPC3 and MDA-MB23 cells), led to dense fibrin network with fine fibers. Low TF expressing cells MCF7 led to thick fibers. Exogenous TF enhanced the density of fibrin network formed by MCF7 cells. Cancer cells through their inherent profibrinolytic potential migrated within the fiber scaffold. The BXPC3 and MCF7 cells moved in clusters whereas the MDA-MB231 cells moved individually within the fibrin network. FCS decreased the efficiency of PTX and 4OHTam on the viability of cancer cells. ConclusionsThe procoagulant signature of cancer cells is determinant for the quality and structure of fibrin network in the microenvironment. Original SEM images show the architecture of “bird's nest”-like fibrin network being in touch with the cell membranes and surrounding cancer cells. Fibrin network constructed by triggering thrombin generation by cancer cells, provides a scaffold for cell migration. Fibrin clot shields protect cancer cells against PTX and 4OHTam.

Antitumoral activity of different Amaryllidaceae alkaloids: In vitro and in silico assays

Ethnopharmacology relevanceThe plants of Amaryllidaceae family, such as Amaryllis belladonna L., have been used as herbal remedies for thousands of years to address various disorders, including diseases that might today be identified as cancer. Aim of the studyThe objective of this work was to evaluate the potential of three Amaryllidaceae alkaloids against four cancer cell lines. Material and methodsThe alkaloids lycorine, 1-O-acetylcaranine, and montanine were evaluated in vitro against colon adenocarcinoma cell line (HCT-116) and breast carcinoma cell lines (MCF-7, MDAMB231, and Hs578T). Computational experiments (target prediction and molecular docking) were conducted to gain a deeper comprehension of possible interactions between these alkaloids and potential targets associated with these tumor cells. ResultsMontanine presented the best results against HCT-116, MDAMB231, and Hs578T cell lines, while lycorine was the most active against MCF-7. In alignment with the target prediction outcomes and existing literature, four potential targets were chosen for the molecular docking analysis: CDK8, EGFR, ER-alpha, and dCK. The docking scores revealed two potential targets for the alkaloids with scores similar to co-crystallized inhibitors and substrates: CDK8 and dCK. A visual analysis of the optimal docked configurations indicates that the alkaloids may interact with some key residues in contrast to the other docked compounds. This observation implies their potential to bind effectively to both targets. ConclusionsIn vitro and in silico results corroborate with data literature suggesting the Amaryllidaceae alkaloids as interesting molecules with antitumoral properties, especially montanine, which showed the best in vitro results against colorectal and breast carcinoma. More studies are necessary to confirm the targets and pharmaceutical potential of montanine against these cancer cell lines.

Effects of solid lipid nanocarrier containing methyl urolithin A by coating folate-bound chitosan and evaluation of its anti-cancer activity

BackgroundNanotechnology-based drug delivery systems have received much attention over the past decade. In the present study, we synthesized Methyl Urolithin A-loaded solid lipid nanoparticles decorated with the folic acid-linked chitosan layer called MuSCF-NPs and investigated their effects on cancer cells.MethodsMuSCF-NPs were prepared using a high-pressure homogenization method and characterized using FTIR, FESEM, DLS, and zeta potential methods. Drug encapsulation was assessed by spectrophotometry and its cytotoxic effect on various cancer cells (MDA-MB231, MCF-7, PANC, AGS, and HepG2) by the MTT method. Antioxidant activity was assessed by the ABTS and DPPH methods, followed by expression of genes involved in oxidative stress and apoptosis by qPCR and flow cytometry.ResultsThe results showed the formation of monodisperse and stable round nanoparticles with a size of 84.8 nm. The drug loading efficiency in MuSCF-NPs was reported to be 88.6%. MuSCF-NPs exhibited selective cytotoxicity against MDA-MB231 cells (IC50 = 40 μg/mL). Molecular analysis showed a significant increase in the expression of Caspases 3, 8, and 9, indicating that apoptosis was occurring in the treated cells. Moreover, flow cytometry results showed that the treated cells were arrested in his SubG1 phase, confirming the pro-apoptotic effect of the nanoparticles. The results indicate a high antioxidant effect of the nanoparticles with IC50 values ​​of 45 μg/mL and 1500 μg/mL against ABTS and DPPH, respectively. The reduction of catalase gene expression confirmed the pro-oxidant effect of nanoparticles in cancer cells treated at concentrations of 20 and 40 μg/mL.ConclusionsTherefore, our findings suggest that the MuSCF-NPs are suitable candidates, especially for breast cancer preclinical studies.

Cytotoxic Effects of Green Synthesis of Zirconium Nanoparticles of Aqueous Clover Extract on Breast Cancer

Background & Aims: Breast cancer is one of the major causes of death among women. In various studies, the effects of synthesized nanoparticles (NPs) on cancer cells have been measured. This investigation aimed to explore the cytotoxic effects of metal zirconium nanoparticles (ZrNPs) synthesized by aqueous extract of clover leaves (Trifolium repens L) on breast cancer cells. Materials and Methods: metal ZrNPs were synthesized utilizing the aqueous extract of clover leaves. Physical and chemical evaluation of the synthesized NPs was done by UV-Vis, EDS, SEM, and DLS analyses. The cytotoxic effects of ZrNPs on MDAMB-468 and HFF cell lines were investigated by the MTT assay and compared with those of Tamoxifen, a chemotherapy medication used to treat breast cancer. Results: The aqueous extract of clover was utilized as a reducing agent in the synthesis of ZrNPs. The size of ZrNPs was 29-81 nm, in irregular polygonal form, and star-shaped, and flower-like colonies were observed homogeneously. MTT test showed that ZrNPs inhibited the growth of MDA-MB-468 cells in a concentration- and time-dependent manner. The IC50 value calculated from the dose-response curve for the MDA-MB-468 cell line was 264.3 μg/mL. Conclusion: The aqueous clover extract showed a suitable ability with green synthesis of NPs. Considering the cytotoxic effects of ZrNPs on breast cancer cell lines, it can be used as an effective therapeutic agent to be examined and evaluated clinically to deal with cancers in future studies.

PFDN4 as a Prognostic Marker Was Associated with Chemotherapy Resistance through CREBP1/AURKA Pathway in Triple-Negative Breast Cancer.

Breast cancer is the most common malignancy and its incidence is increasing. It is currently mainly treated by clinical chemotherapy, but chemoresistance remains poorly understood. Prefolded proteins 4 (PFDN4) are molecular chaperone complexes that bind to newly synthesized polypeptides and allow them to fold correctly to stabilize protein formation. This study aimed to investigate the role of PFDN4 in chemotherapy resistance in breast cancer. Our study found that PFDN4 was highly expressed in breast cancer compared to normal tissues and was statistically significantly associated with stage, nodal status, subclasses (luminal, HER2 positive and triple negative), triple-negative subtype and disease-specific survival by TCGA database analysis. CRISPR knockout of PFDN4 inhibited the growth of 89% of breast cancer cell lines, and the triple-negative cell line exhibited a stronger inhibitory effect than the non-triple-negative cell line. High PFDN4 expression was associated with poor overall survival in chemotherapy and resistance to doxorubicin and paclitaxel through the CREBP1/AURKA pathway in the triple-negative MDAMB231 cell line. This study provides insightful evidence for the value of PFDN4 in poor prognosis and chemotherapy resistance in breast cancer patients.

Antiproliferative effect of Saraca asoca methanol bark extract on triple negative breast cancer (TNBC)

BackgroundSaraca asoca (Asoka) is reported to possess phytoestrogenic components with anticancer properties. The phytoestrogens are recognized as natural agonists for ERβ, which acts as an antagonist to ERα. Despite the absence of ERα, studies have identified ERβ in 50–80% of triple negative breast cancers (TNBC). Thus, the present study is intended to reveal the role of phytoestrogens of Asoka on TNBC. The cytotoxic effect of Asoka methanol bark extract was analyzed on different breast cancer cell lines by MTT assay. Estrogen-screen assay was employed to determine the proliferative/antiproliferative effect. Identification of phytoestrogens in Asoka was accomplished using LC-MS analysis and in silico docking studies were performed to investigate possible interactions of phytoestrogens with ERα and β.ResultsThe extract of Asoka was found to be cytotoxic against TNBC cell line, MDAMB-231 with IC50 of 70.22 ± 1.89 μg/mL and towards HER+ breast cancer cell line, SKBR3 with IC50 of 98.41 ± 2.31 μg/mL, respectively. Whereas the extract did not show any cytotoxicity towards ERα cell line, MCF-7 even up to the concentration 300 μg/mL. Estrogen-screen assay emphasized an estrogenic effect of the extract on MCF-7 and an anti-estrogenic/antiproliferative effect on MDAMB-231 cells. LC–MS analysis identified phytoestrogens such as β-sitosterol, quercetin, kaempferol and others. The docking results revealed good binding efficacy of phytoestrogens with ERβ than ERα and quercetin shows more affinity with the highest docking score of − 9.220. Strikingly, it was found that the S. asoca methanol extract was preferentially cytotoxic to TNBC cells.ConclusionThe study demonstrates selective anticancer properties of S. asoca methanol extract on TNBC, which indicates a selective impact on ER subtypes. The identification of phytoestrogens, such as β-sitosterol, quercetin and kaempferol, in the Asoka methanol bark extract provides a molecular basis for its observed effects. In silico studies further support the view that these phytoestrogens may preferentially interact with ERβ rather than ERα. Quercetin, in particular, demonstrated the highest binding efficacy with ERβ, suggesting its potential role in mediating the anticancer effects observed in TNBC cells. Further research is warranted to explore the full therapeutic potential of phytoestrogens in breast cancer treatment.

Estrogen-receptor status determines differential regulation of α1- and α2-adrenoceptor-mediated cell survival, angiogenesis, and intracellular signaling responses in breast cancer cell lines.

Psychosocial stress promotes cancer pathogenesis involving angiogenesis through alterations in neuroendocrine-immune functions that may involve adrenoceptor (AR)-dependent signaling mechanisms in the brain, lymphoid organs, and cancerous cells. Various concentrations of α1- and α2- AR-specific agonists and antagonists were incubated in vitro with estrogen receptor-positive (ER +) MCF-7, and ER (-) MDA MB-231 cells to examine the secretions of VEGF-A, VEGF-C, and nitric oxide (NO), and expression of signaling molecules- p-ERK, p-CREB, and p-Akt on the proliferation of breast cancer cell lines. Cellular proliferation, VEGF-A and NO secretion, expression of p-ERK, p-CREB, and p-Akt were enhanced in MCF-7 cells treated with α1-AR agonist while VEGF-C secretion alone was enhanced in MDA MB-231 cells. Treatment of MCF-7 and MDA MB-231 cells with α2- AR agonist similarly enhanced proliferation and decreased NO production and p-CREB expression while VEGF-C secretion was decreased in MCF-7 cells and p-Akt expression was decreased in MDA MB-231 cells. α1-AR inhibition reversed cellular proliferation and VEGF-A secretion by MCF-7 cells while α2-AR inhibition reversed the proliferation of MCF-7 and MDA MB-231 cells and VEGF-C secretion by MCF-7 cells. Taken together, breast cancer pathogenesis may be influenced by distinct α-AR-mediated signaling mechanisms on angiogenesis and lymphangiogenesis that are dependent on estrogen receptor status.

Abstract 1550: Identification of a novel squalene epoxidase function in breast cancer brain metastasis

Abstract Brain metastases are serious complications of breast cancer, especially in triple-negative breast cancer (TNBC) patients. There is currently no effective treatment due to the unique brain microenvironment and limitation for drugs to cross the blood-brain barrier (BBB). BBB limits access of nutrients from the circulation and thereby makes the brain hypoxic and depleted of metabolites, growth factors and proteins. However, it remains poorly understood how breast cancer cells manipulate for adaption and colonization in the brain. To probe the molecular mechanism of breast cancer brain metastasis (BCBM), we compared gene signatures in primary breast tumors and BCBM tumors, and identified that SQLE (encodes squalene epoxidase, the second rate-limiting enzyme in the cholesterol biosynthesis) could be a leading-edge gene in breast cancer brain metastasis. To explore the role of SQLE in BCBM, we established the brain metastatic TNBC MDA-MB-231 (MDA231-BrM) cell line from brain metastatic subpopulation that originated from its parental MDA-MB-231 (MDA231) cell line. We found that SQLE expression was greatly upregulated in MDA231-BrM cells compared with the parental MDA231 cells. Using MDA231-BrM and MDA231 cell lines expressing SQLE shRNAs, we evaluated the effects of SQLE loss on cancer cell migration, invasion, and stemness by wound-healing, transwell invasion/migration, and tumorsphere formation assays. While loss of SQLE greatly attenuated cell invasiveness and stemness in both MDA231 and MDA231-BrM cells, loss of SQLE could only affect the cell migration activity on MDA231 cells but not MDA231-BrM cells. Our RNA-seq data further identified a subset of SQLE-affected genes that is uniquely enriched in MDA231-BrM cells and favors brain extravasation and colonization. To explore the potential function of SQLE in brain extravasation and colonization, we established in vitro BBB models and ex vivo mouse brain slice organotypic cultures. We showed that loss of SQLE inhibited the ability of MDA231-BrM cells to across the BBB-mimic astrocyte-endothelial structures as well as impaired the co-option with blood capillaries in the mouse brain slices. Although SQLE-deficient MDA231-BrM cells could still spread on the surface of the blood vessels, they seemed to undergo apoptosis. Since the ability to invade, migrate, and penetrate is critical for invasion of cancer cells, our results strongly imply the novel function of SQLE in breast cancer cell invasion, penetration, and even colonization in the brain through blood vessel co-option. In summary, our data reveal a novel role for SQLE in two critical requisites for breast-to-brain extravasation and colonization - the ability to penetrate through BBB and to co-opt brain vessels for metastatic expansion. Our findings indicate that targeting SQLE may represent a therapeutic opportunity for breast cancer brain metastases. Citation Format: Shu-Ping Wang, Jia-Yun Yeh, Yu-Ling (Pony) Lee, Kun-Yuan Lin, Chao-Di Chang, Chih-Chieh Yang, Shan-Yun Cheng, Ya-Wen Hung, Yu-Hsien Chang, Yao-Feng Li, Yung-Lung Yu. Identification of a novel squalene epoxidase function in breast cancer brain metastasis [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1550.

Abstract 7592: Combined inhibition of CDK4/6 and AKT is highly active against the luminal androgen receptor (LAR) subtype of triple negative breast cancer (TNBC)

Abstract The LAR subtype of TNBC is enriched for targetable biomarkers such as androgen receptor (AR) expression, PIK3CA mutations, and intact Rb. The purpose of this study was to investigate the most effective combination of CDK4/6, AR, and PI3K-AKT inhibitors in preclinical models of LAR TNBC. The MDAMB453 and MFM223 (AR positive/Rb intact/PIK3CAmutant) LAR TNBC cells were treated with each inhibitor alone or in combination. Drug sensitivity was assessed using colony formation, cell viability, and live-cell analysis. The Loewe additivity equation was used to measure the additive drug effects. Immunoblot analysis was used to evaluate cell cycle and PI3K-AKT signaling and ARE luciferase assay was used to assess AR transcriptional activity. MDAMB453 and MFM223 cells were sensitive to the single agents palbociclib, alpelisib, and capivasertib (IC50, ~500 nM), which inhibited CDK4/6, PI3Kα, and AKT, respectively. Enzalutamide, an AR antagonist, exerted no growth inhibitory activity (IC50, 15-25 μM). Treatment with palbociclib, alpelisib, or capivasertib did not alter the AR protein levels or transcriptional activity. The combination of palbociclib+capivasertib synergistically inhibited the proliferation of MDAMB453 and MFM223 cells (synergistic scores 7.34, p=5.81-11, and 4.78, p=0.012, respectively) better than palbociclib+alpelisib. Enzalutamide did not enhance either combination. Palbociclib+capivasertib inhibited PI3KCA-mutant and Rb-intact LAR TNBC PDX growth more potently than palbociclib+alpelisib (p=0.046). Treatment of LAR TNBC cells with palbociclib suppressed Rb phosphorylation and resulted in adaptive activation of P-AKTS473/T308 and the AKT substrates GSK3β, PRAS40, and FoxO3a after 24 h. Capivasertib inhibited the phosphorylation of AKT and AKT substrates, following CDK4/6 blockade with palbociclib, more potently than alpelisib. PI3Kβ inhibitors (TGX221, GSK2636771) did not block AKT substrate upregulation, suggesting PI3Kβ does not mediate adaptive responses. Rictor knockdown failed to reduce AKT activation following palbociclib treatment, suggesting an mTORC2-independent mechanism. Human Phospho-kinase Array of MDA-MB-453 cells treated with palbociclib showed time dependent upregulation of GSK3βS9, STAT3Y727 and PDFGRβY751. PDGFRβ activation after palbociclib treatment was confirmed in MFM223 cells. PDGFRβ siRNAs in MDAMB453 cells blocked P-AKTS473 upregulation after palbociclib treatment. Treatment with palbociclib and the PDGFRβ small-molecule antagonist CP673451 arrested LAR TNBC growth similar to palbociclib+capivasertib, suggesting an adaptive response involving PDGFRβ signaling. In conclusion, this study supports the clinical testing of the palbociclib and capivasertib combination for LAR TNBC patients and reveals adaptive responses after palbociclib treatment through PDGFRβ signaling. Citation Format: Rosario Chica-Parrado, Gun Min Kim, Yasuaki Uemoto, Dan Ye, Fabiana Napolitano, Chang-Ching Lin, Emmanuel Bikorimana, Kyung-min Lee, Saurabh Mendiratta, Ariella B. Hanker, Carlos L. Arteaga. Combined inhibition of CDK4/6 and AKT is highly active against the luminal androgen receptor (LAR) subtype of triple negative breast cancer (TNBC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7592.

Abstract 2960: Deciphering the role of miRNA146-a and its crosstalk with cellular redox state in senescence escape in breast cancer cells

Abstract Senescence serves as a double-edged sword in cancer as studies revealed that senescence exhibits both tumor-suppressing and tumor-promoting effects. A subpopulation of cancer cells that enters senescence can evade senescence to proliferate, thereby resulting in tumor regrowth, which has been associated with chemoresistance and tumor aggressiveness. Unlike senescent cells, the senescence-escaped cells harbor low levels of reactive oxygen species (ROS), however, the mechanism(s) underlying this redox dichotomy in senescence and senescence evasion remains elusive. In this regard, recent reports have highlighted the pivotal role of miRNAs in regulating cellular senescence. To that end, miR-146a has been reported as a biomarker of senescence probably via modulating pro-inflammatory and antioxidant pathways. We set up a model of doxorubicin-induced senescence in MDA-MB-231 breast carcinoma cells to study the role and involvement of miRNA146a in senescence induction and its regulation. Senescence induction was confirmed by upregulation of p21, increase in senescence-associated beta galactosidase and C12FDG staining, as well as propidium iodide positivity. We show that, following the initial phase of apoptotic cell death, as evidenced by increased yH2AX and cleaved caspase 3, a population of senescent cells escaped growth arrest to re-enter cell cycle and proliferate. Senescence-escaped cells harbored lower ROS levels compared to senescent cells, which correlated with upregulation of antioxidant enzymes such as MnSOD and CuZnSOD as well as increased transcription of NRF2 and NQO1. Our results also provide evidence for a novel senescence associated redox state, which implicates intracellular peroxynitrite as a driver of cellular senescence. Interestingly, in our model system, p21 upregulation was not associated with intracellular ROS accumulation, which was reported in earlier findings. Interestingly, these changes coincided with a significant increase in miR-146 expression (during senescence), which was previously shown to downregulate ROS in other model systems. While modulating miR-146a did not seem to change ROS levels upon doxorubicin-induced senescence in MDA-MB231 cells, the precise crosstalk between cellular ROS, miR146-a and senescence evasion is currently being pursued. Citation Format: Shazib Pervaiz, Angeline Q. Liew, Marie-Veronique Clement. Deciphering the role of miRNA146-a and its crosstalk with cellular redox state in senescence escape in breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 2960.

Abstract 6429: Critical role of elevated TMEM176B gene expression in humanized patient-derived xenografts mouse models of triple negative breast cancer

Abstract Objective: In the cancer research, a highly promising in vivo platform for personalized treatment involves the adoption of an advanced approach—specifically, the grafting of patient-derived xenografts (PDX) onto humanized mouse models. These models capture distinctive aspects of interaction with the human immune system and the tumor microenvironment (TME). In this study, we have engineered humanized triple-negative breast cancer (TNBC) PDX models to observe alterations in differentially expressed genes, thereby enhancing our understanding of the intricacies of personalized treatment in this context. Method: We utilized two TNBC PDX models established for the humanized models, where CD34+ hematopoietic stem cells were transplanted into immunodeficient mice. RNA sequencing was performed to identify altered gene expression in humanized PDX models compared to NSG PDXs. Additionally, we generated stable cell lines overexpressing TMEM176B in MDAMB231 and Hs578T cells, and we knocked down TMEM176B in 4T1 cells using recombinant techniques Results: In the humanized model, the growth of PDX tumors did not show a significantly faster or markedly different rate compared to previous studies. However, upon conducting RNA sequencing in the PDX model, the expression of the TMEM176B gene was consistently downregulated. Consequently, we transfected and observed that the increased expression of TMEM176B in MDAMB231 and Hs578T cell lines resulted in enhanced cell proliferation in vitro. Transplanting MDAMB231 cells overexpressing TMEM176B into athymic nude mice resulted in accelerated tumor growth. The study further investigates the expression of TMEM176B in an immune-competent environment by knocking down the gene in 4T1 cells or transplanting the control group into a balb/c mouse model. Tumors with TMEM176B knockdown exhibited inhibited growth, increased CD3+ T cell infiltration, and significant inhibition when treated with anti-PD-L1 compared to the control group. Conclusion: This research demonstrates the utility of PDX models, particularly humanized PDX models, in studying the complexities of cancer biology and the tumor microenvironment. The findings regarding TMEM176B and its role in tumorigenesis and immune responses in triple-negative breast cancer provide valuable insights for further research and potential therapeutic interventions. Citation Format: Yujeong Her, Jihui Yun, Woohang Heo, Jong-Il Kim, Han-Byoel Lee, Wonshik Han, Hyeong-Gon Moon. Critical role of elevated TMEM176B gene expression in humanized patient-derived xenografts mouse models of triple negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 6429.

Abstract 551: Investigation of the antipoliferative effect of the Xylopia Aethiopicaextract in triple-negative breast cancer cells

Abstract Triple-negative breast cancer (TNBC) is the most aggressive subtype of breast cancer and has very limited treatment options. Xylopia Aethiopica (XA) is a common spice that is widely used in the regions of central and western Africa. It is known to have various pharmacological properties, one of which is anti-inflammatory activity. The anti-inflammatory effect may portend antiproliferative activity. We hypothesized that the extract of XA will exert antiproliferative activity against TNBC cells. The study aimed to establish the molecular mechanism underlying the antiproliferative activity of XA extract (XAE) against TNBC. The dried fruits of XA were crushed in a mixer and macerated using diethyl ether for 72 h. The macerate was subjected to vacuum and rotary evaporation to remove the organic solvent, and a stock solution was prepared in dimethyl sulfoxide (DMSO). Assessment of the efficacy of XAE was performed using serial dilutions (100 µg/ml, 50 µg/ml, 10 µg/ml, 5 µg/ml, and 1µg/ml) of the XAE stock solution, followed by in vitro testing against two TNBC cell lines (MDA-MB-231, and MDA-MB-468 cells). The cytotoxic effect of the XAE was then measured using the resazurin dye assay. XAE resulted in a concentration-dependent cell death in both cell lines. At the highest concentration (100 µg/ml), XAE induced cytotoxic cell death of 89% and 91% in MDAMB231 and MDAMB468 cells, respectively. This was consistent with IC50 values of 32.95 ± 1.32 µg/ml (MDAMB231) and 20.83 ± 1.05 µg/ml (MDAMB468). At the molecular level, western blot analysis of mitogenic markers associated with MAPK oncogenic signaling pathway demonstrated the inhibition of EGFR and AKT protein levels after a 48-h treatment. Acridine orange-ethidium bromide (AO/EB) staining showed a concentration-dependent induction of apoptosis in both cell lines. Flow cytometric analysis was performed to quantify the apoptotic cells. A significant increase of apoptotic cells was observed in treatment groups as compared to control after 72 h. Apoptotic induction was associated with increased p53 protein levels after 48 h treatment compared to control. The study results underscore the anticancer effects of XAE in TNBC cells mediated through induction of apoptosis. Citation Format: Shailvi Soni, Shail Rakesh Modi, Terrick Andey. Investigation of the antipoliferative effect of the Xylopia Aethiopicaextract in triple-negative breast cancer cells [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 551.

Abstract 7198: A small molecule Notch1 inhibitor (ASR490) restores chemosensitivity in triple-negative breast cancer

Abstract Metastatic triple-negative Breast cancer (mTNBC) is an aggressive and often a chemo resistant disease for which no effective druggable target has yet been identified. We and others reported that the aberrant expression of neurogenic locus Notch homolog protein 1 (Notch1) serves as a molecular signature for TNBC. Hence, we postulated that pharmacologically targeting Notch1 in conjunction with a standard chemotherapeutic agent (Doxorubicin: DXR) may completely eradicate TNBC growth and overcome systemic and debilitating toxicity. Hence, this study aims to elucidate the role of our recently discovered notch1 inhibitor ASR490 and its ability to chemosensitize TNBC without significant systemic toxicity. In our results, pretreatment of 1/10 th of the inhibitory concentration of ASR490 combined with 1/10 th or 1/20th of DXR significantly inhibited the growth of TNBC cells (MDA-MB-231 and BT549). Notably, DXR treatment induced Notch1 activation which led to chemoresistance in TNBC; however, co-treatment with the Notch1 inhibitor ASR490, led to the downregulation of Notch1 activation and eradication of the cell viability and clonogenicity of the TNBC cells. Further, molecular analysis suggested that pretreatment of 1/10th of ASR490 facilitates DXR-mediated sensitivity, by inhibiting the DNA repair pathway and upregulating (cleaved) caspase 3, (cleaved) caspase-9 and poly (ADP-Ribose) polymerase (PARP)-mediated apoptosis. Similarly, the combination effectively blocked the epithelial and mesenchymal transition (EMT) regulators and suppressed metastatic properties of MDA-MB231 and BT-549 cells. Moreover, combining ASR490(1/10th) and DXR (1/20th) significantly eradicated xenotransplanted TNBC tumors compared to ASR490 or DXR alone. In addition to being effective at inhibiting tumor growth, the significantly lower dose requirements of DXR and ASR490 in combination makes it a highly safe therapeutic modality. These findings suggest that aberrant activation of Notch1 is responsible for TNBC chemoresistance and concomitantly inhibiting Notch1 activation is an effective therapeutic strategy to restore chemosensitivity in TNBC. Citation Format: Neha Tyagi, Balaji Chandrasekaran, Ashish Tyagi, Balpreet Singh, Megha Chandran, Amandeep Singh, Arun Sharma, Chendil Damodaran. A small molecule Notch1 inhibitor (ASR490) restores chemosensitivity in triple-negative breast cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7198.

Abstract 3074: Regulating lactate levels in triple negative breast cancer presents a promising avenue for therapeutic intervention

Abstract Introduction: Among all subtypes of breast cancer, triple-negative breast cancer (TNBC) is associated with the most unfavorable prognosis, emphasizing the critical need to pinpoint therapeutic targets tailored to TNBCs. Lactate, produced as a by-product of aerobic glycolysis, acts as an oncometabolite and plays a substantial role in promoting tumor aggressiveness, particularly in TNBCs. In our ongoing laboratory investigations, we are actively exploring strategies to mitigate the influence of lactate on TNBCs. Methods: The experiments utilized two triple-negative breast cancer (TNBC) cell lines, i.e., MDA-MB231 and MDA-MB468. The inhibitors employed in this study are FOXY5, XAV939, PFK15, and Quercetin. Protein expression was examined using Western blotting and Immunofluorescence assays. Trans-well and wound healing assays were employed to assess cell migration and invasion. Colony formation assays (CFU) were utilized to investigate stem cell potential and proliferation. In vivo experiments were conducted using 4T1-orthotopic Balb/c mice. Results: Using triple-negative breast cancer (TNBC) cells, we have demonstrated the pivotal role of the WNT/β-catenin signaling pathway in promoting the generation of extracellular lactate, thus driving the progression and metastasis of TNBCs. Additionally, we have shown that inhibiting lactate production in TNBC cells, and consequently impeding cell migration and invasion, can be achieved by using recombinant WNT5A or its mimicking hexa-peptide FOXY5. Similarly, employing a β-catenin inhibitor such as XAV939 can yield comparable outcomes in relation to TNBC cells. In an alternative approach, we conducted inhibition experiments targeting PFKFB3 (6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase), a key regulator of aerobic glycolysis in cancer cells. Our findings indicate that a combined approach involving siPFKL and iPFKFB3 is more promising in suppressing lactate production in TNBCs when compared to the effects of individual iPFKFB3 treatment. Conclusions: Our present investigations suggest that employing inhibitors targeting the WNT/β-catenin signaling pathway, PFKP, and PFKEB3 could be a promising therapeutic strategy to effectively reduce lactate levels in TNBCs. Citation Format: Chandra Prakash Prasad, Sheikh Mohammad Umar, Arundhathi Dev J. R., Akanksha Kashyap, Meetu Rathee. Regulating lactate levels in triple negative breast cancer presents a promising avenue for therapeutic intervention [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3074.

Abstract 7591: Tumor Treating Fields (TTFields) show efficacy in Triple-Negative breast cancer (TNBC) cells alone and in combination with PARP inhibitor Talazoparib

Abstract Breast cancer is the most common cancer in women worldwide, and the fifth leading cause of cancer-related deaths globally. Triple-negative breast cancer (TNBC), the most aggressive form of breast cancer, is usually treated with surgery, chemotherapy, and radiation. Tumor Treating Fields therapy are FDA-approved for the treatment of glioblastoma (GBM) and malignant pleural mesothelioma (MPM).TT Fields use alternating electric fields to inhibit tumor growth through mitotic disruption, cellular damage, integrated stress response activation, and immune mechanisms and inhibit cell proliferation, induce cell death, and cause cell cycle arrest.TT Fields can induce BRCAness and when combined with PARP inhibition, this combination may result in synthetic lethality. We explored the effect of TTFields on two TNBC cell lines MDA-MB436 (BRCA1-mutant, p53-null) and MDA-MB468 (BRCA1 wild-type, p53-mutant) treated with TTFields (150 kHz) for 24 hours. Western blot analysis showed elevation of p21 independent of p53 mutational status. We examined the combination of PARP inhibitor (Talazoparib) with TTFields in MDA-MB468 cells to determine the effect of the combination in BRCA wild-type cancer cells. Western blot analysis showed p21 upregulation after 24 hours in combination without an increase in p53. p21 acts as a G1-checkpoint protein and loss of p21 expression has been observed in a high percentage of human breast cancer cells. Our results suggest a rational and potentially effective therapy that could be further developed and used for the treatment of breast cancer. Our ongoing studies are exploring potential mechanisms of synergy between PARP inhibitor Talazoparib and TTFields using various TNBC models, and the effect of the combination on cell cycle arrest in cell culture and in vivo. Citation Format: Maryam Ghandali, Praveen Srinivasan, Yutong Xia, Eric T. Wong, Robert W. Sobol, Lanlan zhou, Benedito A. Carneiro, Stephanie L. Graff, Wafik S. El-Deiry. Tumor Treating Fields (TTFields) show efficacy in Triple-Negative breast cancer (TNBC) cells alone and in combination with PARP inhibitor Talazoparib [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 7591.

Hexachlorobenzene as a differential modulator of the conventional and metronomic chemotherapy response in triple negative breast cancer cells.

Triple negative breast cancer (TNBC) is usually treated with high doses of paclitaxel, whose effectiveness may be modulated by the action of environmental contaminants such as hexachlorobenzene. High doses of paclitaxel cause adverse effects such as low cellular selectivity and the generation of resistance to treatment due to an increase in the expression of multidrug resistance proteins (MRPs). These effects can be reduced using a metronomic administration scheme with low doses. This study aimed to investigate whether hexachlorobenzene modulates the response of cells to conventional chemotherapy with paclitaxel or metronomic chemotherapy with paclitaxel plus carbachol, as well as to study the participation of the MRP ATP-binding cassette transporter G2 (ABCG2) in human TNBC MDA-MB231 cells. Cells were treated with hexachlorobenzene alone or in combination with conventional or metronomic chemotherapies. The effects of treatments on cell viability were determined by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay and the nuclear factor kappa B pathway participation was evaluated using a selective inhibitor. ABCG2 expression and its modulation were determined by western blot. Results confirmed that paclitaxel reduces MDA-MB231 cell viability in a concentration-dependent manner. Results also showed that both conventional and metronomic chemotherapies reduced cell viability with similar efficacy. Although hexachlorobenzene did not modify cell viability per se, it did reverse the effect induced by the conventional chemotherapy, without affecting the efficacy of the metronomic chemotherapy. Additionally, a differential modulation of ABCG2 expression was determined, mediated by the nuclear factor kappa B pathway, which was directly related to the modulation of cell sensitivity to another cycle of paclitaxel treatment. The findings indicate that, in human TNBC MDA-MB231 cells, in the presence of hexachlorobenzene, the metronomic combination of paclitaxel plus carbachol is more effective in affecting the tumor biology than the conventional therapeutic administration scheme of paclitaxel.

A new copper(II) complex containing long-chain aliphatic hydrazide and 1,10-phenanthroline upregulates ADP hydrolysis in triple-negative breast cancer cells

Copper can be opportunely complexed to modulate oncogenic pathways, being a promising strategy for cancer treatment. Herein, three new copper(II) complexes containing long-chain aliphatic hydrazides and 1,10-phenanthroline (1,10-phen), namely, [Cu(octh)(1,10-phen)(H2O)](NO3)21, [Cu(dech)(1,10-phen)(H2O)](NO3)22 and [Cu(dodh)(1,10-phen)(H2O)](NO3)2.H2O 3 (where octh = octanoic hydrazide, dech = decanoic hydrazide, dodh = dodecanoic hydrazide) were successfully prepared and characterized by several physical-chemical methods. Furthermore, X-ray structural analysis of complex 2 indicated that the geometry around the copper(II) ion is distorted square-pyramidal, in which hydrazide and 1,10-phenanthroline act as bidentate ligands. A water molecule in the apical position completes the coordination sphere of the metal ion. All new copper(II) complexes were cytotoxic to breast cancer cell lines (MCF7, MDA-MB-453, MDA-MB-231, and MDA-MB-157) and selective when compared to the non tumor lineage MCF-10A. In particular, complex 2 showed half-maximal inhibitory concentration (IC50) values ranging between 2.7 and 13.4 μM in MDA-MB231 cells after 24 and 48 h of treatment, respectively. Furthermore, this complex proved to be more selective for tumor cell lines when compared to doxorubicin and docetaxel. Complex 2 inhibited the clonogenicity of MDA-MB231 cells, increasing adenosine diphosphate (ADP) hydrolysis and upregulating ecto-nucleoside triphosphate diphosphohydrolase 1 (ENTPD1) transcriptional levels. In this sense, we suggest that the inhibitory effect on cell proliferation may be related to the modulation of adenosine monophosphate (AMP) levels. Thus, a novel copper(II) complex with increased cytotoxic effects and selectivity against breast cancer cells was obtained, contributing to medicinal chemistry efforts toward the development of new chemotherapeutic agents.

A novel sensor for nicotinamide adenine dinucleotide based on poly-3, 4-ethylenedioxythiophene-coordinated gold nanoparticle-functionalized acupuncture needle microelectrode

Reduced nicotinamide adenine dinucleotide (NADH) plays crucial roles in maintaining cell growth and differentiation, cytoprotection and energy metabolism. And it is imperative to precisely monitor the variable quantity of NADH. Herein, the connotative feature of acupuncture needle (AN) was explored as electrochemical matrix. Poly-3, 4-ethylenedioxythiophene-liganded gold nanoparticle modified AN electrode (ANE/AuNPs/PEDOT) was prepared via a simple electrosynthesis technology. Working together by charge transfer and reaction has a strong response to the electron-transfer of “N” in NADH, which is coordinately presented as a current peak. Interestingly, the behavior of electron-transfer was affected by ambient environment. After the conditional optimization, the fabricated sensor exhibited good linear range of 20 ∼ 500 μmol/L with a detection limit of 18.5 μmol/L. In addition, the sensor can be successfully applied to analysis NADH in serum. Furthermore, the microelectrode exhibits the real-time monitor ability for NADH that released from MDA-MB231 cells. This sensor also possesses the significant performance of high selectivity, stability and reproducibility. Based on the acupuncture history, the developed ANE should be a fascinating microsensor besides the low price, fast response and user-friendly operation.