Triple-negative Breast Cancer Cells Research Articles

Selenium and Triple Negative Breast Cancer

Background. The deadliest, most dangerous subtype of breast cancer is triple-negative, which lacks treatment targets and accounts for 30% of all breast cancer-related deaths worldwide. TNBC is characterized by the expression of no estrogen, proges- terone, or human epidermal growth factor 2 receptors. This suggests that new treatment modalities with fewer adverse effects are required. Objective. The aim of the present study was to investigate the therapeutic potential of selenium compounds as an adjuvant therapy for Triple Negative Breast Cancer (TNBC), either on their own or in conjunction with nutritional supplements and chemotherapy medications. Methods. Using the keywords “selenium” and “triple negative breast cancer”, a thorough search was conducted in the PubMed database, yielding 23 articles. The following factors were taken into consideration for inclusion: studies using TNBC cell culture lines or in vivo tumors/specimens; full-text articles from the PubMed database; studies published in the English language; experiments with statistically significant results; and selenium used alone or in combination with other antioxidants or chemotherapy. This led to the evaluation of 13 articles in this review. Results. The results show that selenium therapy increased the anti-cancer drug’s effects and produced tumor cytotoxicity, while reducing the cellular features of the cancer (hyperproliferation, growth, and metastasis). Discussion. This study evaluated the various selenium compounds tested, the cell lines and model organisms used, the assays performed, and the cellular pathways affected. Conclusion. Examining the possible benefits of selenium in TNBC treatment highlights the need for more studies to confirm selenium compounds as viable co-therapeutic agents.

Targeting Cross‐Talks of Notch and VEGF to Tweak the EMT and EPT Dynamics in Triple Negative Breast Cancer Cells

AbstractThe associations of the Notch pathway with the major oncogenic pathways (especially the receptor tyrosine kinases, RTKs) are primarily responsible for inducing EMT (epithelial to mesenchymal transition), angiogenesis, and chemoresistance. In this study, Axitinib is used in combination with LY411575 (γ‐secretase inhibitor) and it is observed that the co‐treatment synergistically induced apoptosis (by 37.36% in MDAMB231 and 27.9% in MDAMB468), arrests cells at the G2/M phase, decreases the stemness properties of the triple‐negative breast cancer (TNBC) cells. It also diminishes the spheroid forming ability, enhances the expression of epithelial markers, such as E‐cadherin (by 2.2 fold in MDAMB231 and 2.51 fold in MDAMB468), and downregulated the expression of mesenchymal markers. Additionally, the protein expression profile of the pro‐oncogenic and pro‐survival genes also reduces significantly after the administration of co‐therapy, which is highlighted by a reduction in the levels of pEGFR, pFAK, pMAPK, NF‐κB, etc. Moreover, the expression of pericyte markers (such as PDGFRs, α‐SMA, c‐kit, and NG2) reduces significantly in both TNBC cells upon co‐treatment, thereby hinting toward the inhibition of epithelial‐to‐pericyte transition (EPT). The current work endows with the effectiveness of the co‐therapy on the EMT and EPT dynamics of TNBC upon inhibition of the major crosstalk between the Vascular endothelial growth factor (VEGF)t and Notch pathway.

Amorphous silica nanoparticles exhibit antitumor activity in triple-negative breast cancer cells.

Triple-negative breast cancer (TNBC) is an aggressive subtype of breast cancer that is mainly treated with cytotoxic chemotherapy. However, this treatment is not always effective, and an important percentage of patients develop recurrence. Nanomaterials are emerging as alternative treatment options for various diseases, including cancer. This work reports the synthesis, characterization, antitumor activity evaluation, and sub-acute toxicity studies of two formulations based on amorphous silica nanoparticles (SiNPs). They are functionalized with 3-aminopropyltriethoxisilane (Si@NH2) and folic acid (FA; Si@FA). The results show that SiNPs reduce the viability and migration of TNBC MDA-MB-231 and 4T1 cell lines and Si@FA do not affect the growth of the mammary nonmalignant HC11 cells. In addition, Si@FA induces reactive oxygen species (ROS) generation and displays antiproliferative and subsequently proapoptotic effects in MDA-MB-231 cells. Moreover, none of the SiNPs cause signs of sub-acute toxicity in mice when administered at 30 mg/kg over a month. In conclusion, these nanosystems display intrinsic antitumor activity without causing toxic in vivo effects, being a promising therapeutic alternative for TNBC.

Cytotoxic properties, glycolytic effects and high-resolution respirometry mitochondrial activities of Eriocephalus racemosus against MDA-MB 231 triple-negative breast cancer

IntroductionTriple-negative breast cancer (TNBC) represents a significant global health crisis due to its resistance to conventional therapies and lack of specific molecular targets. This study explored the potential of Eriocephalus racemosus (E. racemosus) as an alternative treatment for TNBC. The cytotoxic properties and high-resolution respirometry mitochondrial activities of E. racemosus against the MDA-MB 231 TNBC cell line were evaluated.MethodsHexane solvent and bioactive fraction extractions of E. racemosus were performed, while mass spectrometry-based metabolite profiling was used to identify the phytochemical constituents of the extracts. The extracts were further tested against MDA-MB 231 TNBC cells to determine their cytotoxicity. The mode of cell death was determined using flow cytometry. The activities of caspases 3, 8, and 9 were assessed using a multiplex activity assay kit. Glycolytic activity and High-resolution respirometry measurements of mitochondrial function in the MDA-MB 231 cell line were conducted using the Seahorse XFp and Oroboros O2K.ResultsMetabolite profiling of E. racemosus plant crude extracts identified the presence of coumarins, flavonoids, sesquiterpenoids, triterpenoids, and unknown compounds. The extracts demonstrated promising cytotoxic activities, with a half maximal inhibitory concentration (IC50) of 12.84 µg/mL for the crude hexane extract and 15.49 µg/mL for the bioactive fraction. Further, the crude hexane and bioactive fraction extracts induced apoptosis in the MDA-MB-231 TNBC cells, like the reference drug cisplatin (17.44%, 17.26% and 20.25%, respectively) compared to untreated cells. Caspase 3 activities confirmed the induction of apoptosis in both cisplatin and the plant crude extracts, while caspase 8 and 9 activities confirmed the activation of both the intrinsic and extrinsic apoptosis pathways. Increased levels of glycolytic activity were observed in the hexane crude extract. High-resolution respiratory measurements showed elevated mitochondrial activities in all mitochondrial states except for complex-IV activity.ConclusionThese findings support further exploration of E. racemosus as a potential therapeutic agent for TNBC, offering a promising avenue for the development of targeted treatments with minimal adverse effects.

Comparison of Mitochondrial and Antineoplastic Effects of Amiodarone and Desethylamiodarone in MDA-MB-231 Cancer Line.

Previously, we have demonstrated that amiodarone (AM), a widely used antiarrhythmic drug, and its major metabolite desethylamiodarone (DEA) both affect several mitochondrial processes in isolated heart and liver mitochondria. Also, we have established DEA's antitumor properties in various cancer cell lines and in a rodent metastasis model. In the present study, we compared AM's and DEA's mitochondrial and antineoplastic effects in a human triple-negative breast cancer (TNBC) cell line. Both compounds reduced viability in monolayer and sphere cultures and the invasive growth of the MDA-MB-231 TNBC line by inducing apoptosis. They lowered mitochondrial trans-membrane potential, increased Ca2+ influx, induced mitochondrial permeability transition, and promoted mitochondrial fragmentation. In accordance with their mitochondrial effects, both substances massively decreased overall, and even to a greater extent, mitochondrial ATP production decreased, as determined using a Seahorse live cell respirometer. In all these effects, DEA was more effective than AM, indicating that DEA may have higher potential in the therapy of TNBC than its parent compound.

Three-dimensional analysis of mitochondria in a patient-derived xenograft model of triple negative breast cancer reveals mitochondrial network remodeling following chemotherapy treatments.

Mitochondria are hubs of metabolism and signaling and play an important role in tumorigenesis, therapeutic resistance, and metastasis in many cancer types. Various laboratory models of cancer demonstrate the extraordinary dynamics of mitochondrial structure, but little is known about the role of mitochondrial structure in resistance to anticancer therapy. We previously demonstrated the importance of mitochondrial structure and oxidative phosphorylation in the survival of chemotherapy-refractory triple negative breast cancer (TNBC) cells. As TNBC is a highly aggressive breast cancer subtype with few targeted therapy options, conventional chemotherapies remain the backbone of early TNBC treatment. Unfortunately, approximately 45% of TNBC patients retain substantial residual tumor burden following chemotherapy, associated with abysmal prognoses. Using an orthotopic patient-derived xenograft mouse model of human TNBC, we compared mitochondrial structures between treatment-naïve tumors and residual tumors after conventional chemotherapeutics were administered singly or in combination. We reconstructed 1,750 mitochondria in three dimensions from serial block-face scanning electron micrographs, providing unprecedented insights into the complexity and intra-tumoral heterogeneity of mitochondria in TNBC. Following exposure to carboplatin or docetaxel given individually, residual tumor mitochondria exhibited significant increases in mitochondrial complexity index, area, volume, perimeter, width, and length relative to treatment-naïve tumor mitochondria. In contrast, residual tumors exposed to those chemotherapies given in combination exhibited diminished mitochondrial structure changes. Further, we document extensive intra-tumoral heterogeneity of mitochondrial structure, especially prior to chemotherapeutic exposure. These results highlight the potential for structure-based monitoring of chemotherapeutic responses and reveal potential molecular mechanisms that underlie chemotherapeutic resistance in TNBC.

Study Reveals a New Approach to Treating Tripple Negative Breast Cancer

riple-negative breast cancer (TNBC) makes up about 15% of all breast cancer cases worldwide. It's particularly hard to treat because it lacks the three common receptors that most therapies target. As a result, most TNBC patients undergo high doses of non-targeted chemotherapy, which often leads to severe side effects such as hair loss, nausea, and pain. The spread of TNBC cells to other organs, such as the brain or lungs, is the main cause of death in patients.

Genistein and daidzein induce ferroptosis in MDA-MB-231 cells.

In recent years, there has been a growing interest in targeting ferroptosis for the treatment and prevention of multiple cancers. This study aimed to assess the contribution of ferroptosis to the antiproliferative effects of genistein (GN) and daidzein (DZ) in breast cancer cell lines. MDA-MB-231 and MCF-7 cells were employed as an in vitro model. The antiproliferative effects of GN and DZ were determined by WST-1 assay in the presence of specific inhibitors of different cell death pathways. The mRNA expressions of Gpx4 and Fsp-1, the levels of lipid peroxidation, glutathione (GSH)/glutathione disulfide (GSSG) ratio, and intracellular iron ion content were assessed in GN- or DZ-treated cells. GN and DZ were found to cause ferroptotic cell death in MDA-MB-231, as confirmed by the reversal of viability when cells were pretreated with ferrostatin-1. Furthermore, both phytochemicals induced biochemical markers of ferroptosis, including lipid peroxidation and iron ions levels, and decreased GSH/GSSG levels. The mRNA expression levels of the main anti-ferroptotic genes, Gpx4 and Fsp-1, were diminished by the treatment of both phytochemicals. Surprisingly, ferroptosis did not play a role in GN- or DZ-induced cell death in MCF-7 cells. Our findings highlight the potential of GN and DZ as ferroptosis inducers in triple-negative breast cancer cells.

LINC01614 activated by SP1 promoted malignant behavior of triple-negative breast cancer cells via the WNT/b-Catenin signaling pathway.

Triple-negative breast cancer (TNBC) represents the most aggressive subtype of breast cancer (BC), characterized by a dismal prognosis. Dysregulated long non-coding RNA LINC01614 might be a potential biomarker for BC as previously reported. Nevertheless, its functions and mechanism in TNBC cells are unclear. The study aimed to study the effects of LINC01614 on TNBC cell migration, invasion, and epithelial-mesenchymal transition (EMT) process as well as the related mechanism. Reverse transcription quantitative polymerase chain reaction was performed to detect the expression of LINC01614 and SP1 in TNBC cells and tissues. The cellular localization of LINC01614 was determined by subcellular fraction assays. Cell counting kit-8 and Transwell invasion assays were conducted for measurement of TNBC cell viability and invasive ability. Cell migration was performed using wound healing assays and Transwell migration assays. Chromatin immunoprecipitation assays and luciferase reporter assays were used to explore the interaction between SP1 and LINC01614. Western blotting was used to assess protein levels of factors involved in EMT process and Wnt/ß-catenin signaling in TNBC cells. LINC01614 expression was elevated in TNBC tissues and cells. LINC01614 knockdown inhibited cell viability as well as migratory and invasive abilities of TNBC cells. LINC01614 knockdown also obstructed EMT process, as shown by E-cadherin upregulation and vimentin downregulation in TNBC cells. SP1 directly bound to the promoter of LINC01614 and activated LINC01614 expression. SP1 overexpression reversed the suppressive effect of LINC01614 knockdown on TNBC cell migration, invasion, and EMT process. Protein levels of Wnt and ß-catenin were diminished by LINC01614 knockdown, and the trend was partially rescued by SP1 overexpression. SP1-induced LINC01614 promoted malignant behavior of TNBC cells by activating the Wnt/ß-catenin signaling pathway.

ZCCHC3 and Efp coordinately contribute to the pathophysiology of triple-negative breast cancer by modulating NCAPH

Triple-negative breast cancer (TNBC) is an aggressive breast cancer subtype with limited targeted therapies and high rates of recurrence. We previously showed that Efp promotes TNBC cell proliferation by regulating cell cycle-related gene expression. Recent studies showed that ZCCHC3 interacts with Efp, promoting Efp signaling in innate immune responses. We here characterize whether ZCCHC3 plays a pathophysiological role in TNBC tumorigenesis. We showed that ZCCHC3 silencing significantly repressed the proliferation of TNBC conventional cultured cells and three-dimensional patient-derived spheroid culture, which we established from a clinical TNBC tissue. RNA-sequencing in TNBC cells defined that “cell division” was a major pathway commonly downregulated by ZCCHC3 and Efp silencing, and NCAPH was a cell division-related gene highly downregulated by ZCCHC3 silencing. In a TNBC cell-derived xenograft model, ZCCHC3-specific siRNA injection successfully reduced in vivo TNBC tumor growth and downregulated NCAPH expression. Overall, our findings demonstrate that ZCCHC3 and Efp coordinately promote TNBC progression by regulating NCAPH expression and that ZCCHC3/Efp/NCAPH pathway can be applied to clinical TNBC management.

Efficacy of Stilbene Derivatives in Sensitizing Breast Cancer Cells to Ionizing Radiation.

One of the treatments for breast cancer is surgical resection of the tumour and prevention of recurrence with postoperative radiotherapy. Unfortunately, radiotherapy is not always effective enough due to the low sensitivity of cancer cells to ionising radiation. This study aimed to evaluate the radiosensitising properties of resveratrol, piceatannol and polydatin on breast cancer cells, which differ in the presence of hormonal receptors on their surface. The experimental part was carried out on triple-negative breast cancer cells (HCC38) and hormone-dependent cells (MCF7). The study assessed the level of cell death, changes in the expression of genes (BAX, BCL-2) and proteins related to the apoptosis process (CASPASE 3, 8 and P53), changes in the expression of antioxidant enzymes (CATALASE, SOD, GPx1/2) and NRF-2. Additionally, the expression level of RAD51 protein and histone H2AX, which are involved in DNA repair processes, was assessed. Statistical significance was evaluated by a two-way analysis of variance (ANOVA) followed by Tukey's post hoc test (p < 0.05). Ionising radiation in combination with resveratrol or piceatannol activates the apoptosis process by internal and external pathways. Greater sensitivity of MCF7 cells compared to HCC38 cells to ionising radiation in combination with resveratrol is associated with a weaker antioxidant response of cells and reduced intensity of DNA damage repair. DNA repair induced by ionising radiation occurs more effectively in HCC38 cells than in MCF7 cells. Resveratrol has the highest radiosensitising potential among the tested stilbene for cells of both lines. The effectiveness of ionizing radiation in combination with resveratrol (to a lesser extent with piceatannol) is more significant in MCF7 than in HCC38 cells.

Discovering the potential of biomaterial-based mesoporous and magneto-luminescent nanohybrid (Nd-doped Hydroxyapatite/Fe3O4) for cancer theragnosis

Multimodality nanoplatforms play a crucial role in advancing medical interventions by integrating multiple functionalities into a single system. However, issues like intricate production processes and biocompatibility persist. Herein, a facile synthesis of a biomaterial-based mesoporous nanocarrier, HAp:Nd+SPIONs@mSiO2 is reported. The nanohybrid with ∼100 nm average size, comprised of Nd-doped hydroxyapatite (HAp:Nd) nanophosphor, Fe3O4 superparamagnetic iron oxide nanoparticles (SPIONs), and mesoporous silica, exhibiting magneto-luminescent properties. The nanohybrid showed NIR to NIR photoluminescence properties important for deep tissue imaging. The mesoporous nanohybrid was loaded with Indocyanine green (ICG), a photosensitizer and photothermal dye, as a model drug (∼6 μg/mg of nanoparticles) with a high absorption stability retaining >75 % drug until 24 h incubation in pH 6 and 7.4, respectively. Nanoparticles demonstrated dual functionality by generating heat through magnetic and photonic stimulation, as well as producing reactive oxygen species (ROS) upon excitation with 808 nm light. In vitro assays on aggressive triple-negative breast cancer cells (MDA-MB-231) showed the high biocompatibility of nanohybrid with and without ICG, while a significant toxicity was seen after irradiation of NIR light due to ROS production. Noticeably, the nanohybrids also exhibit the ability to monitor temperature changes via Nd3+ associated NIR luminescence. The nanoplatform integrates clinically relevant components like hydroxyapatite, SPIONs, mesoporous silica and ICG, highlighting its potential for translational applications. The developed nanohybrids, with combined NIR-mediated photothermal and photodynamic effects, magnetic photothermal capabilities, and NIR/MR imaging, offer promise in addressing cancer heterogeneity and improving conventional treatments with reduced side effects.

Auraptene Boosts the Efficacy of the Tamoxifen Metabolites Endoxifen and 4-OH-Tamoxifen in a Chemoresistant ER+ Breast Cancer Model.

Approximately 80% of breast cancer (BC) cases are estrogen receptor positive (ER+) and sensitive to hormone treatment; Tamoxifen is a prodrug, and its main plasmatic active metabolites are 4-hydroxytamoxifen (4-OH Tam) and endoxifen. Despite the effectiveness of tamoxifen therapy, resistance can be developed. An increment in eukaryotic initiation factor-4A complex (eIF4A) activity can result in tamoxifen-resistant tumor cells. For this work, we developed a cell variant resistant to 4-OH Tam and endoxifen, denominated MCF-7Var E; then, the aim of this research was to reverse the acquired resistance of this variant to tamoxifen metabolites by incorporating the natural compound auraptene. Combination treatments of tamoxifen derivatives and auraptene successfully sensitized the chemoresistant MCF-7Var E. Our data suggest a dual regulation of eIF4A and ER by auraptene. Joint treatments of 4-OH Tam and endoxifen with auraptene identified a novel focus for chemoresistance disruption. Synergy was observed using the auraptene molecule and tamoxifen-derived metabolites, which induced a sensitization in MCF-7Var E cells and ERα parental cells that was not observed in triple-negative breast cancer cells (TNBC). Our results suggest a synergistic effect between auraptene and tamoxifen metabolites in a resistant ER+ breast cancer model, which could represent the first step to achieving a pharmacologic strategy.

Development of Dual-Targeted Mixed Micelles Loaded with Celastrol and Evaluation on Triple-Negative Breast Cancer Therapy.

Considering that the precise delivery of Celastrol (Cst) into mitochondria to induce mitochondrial dysfunction may be a potential approach to improve the therapeutic outcomes of Cst on TNBC, a novel tumor mitochondria dual-targeted mixed-micelle nano-system was fabricated via self-synthesized triphenylphosphonium-modified cholesterol (TPP-Chol) and hyaluronic acid (HA)-modified cholesterol (HA-Chol). The Cst-loaded mixed micelles (Cst@HA/TPP-M) exhibited the characteristics of a small particle size, negative surface potential, high drug loading of up to 22.8%, and sustained drug release behavior. Compared to Cst-loaded micelles assembled only by TPP-Chol (Cst@TPP-M), Cst@HA/TPP-M decreased the hemolysis rate and upgraded the in vivo stability and safety. In addition, a series of cell experiments using the triple-negative breast cancer cell line MDA-MB-231 as a cell model proved that Cst@HA/TPP-M effectively increased the cellular uptake of the drug through CD44-receptors-mediated endocytosis, and the uptake amount was three times that of the free Cst group. The confocal results demonstrated successful endo-lysosomal escape and effective mitochondrial transport triggered by the charge converse of Cst@HA/TPP-M after HA degradation in endo-lysosomes. Compared to the free Cst group, Cst@HA/TPP-M significantly elevated the ROS levels, reduced the mitochondrial membrane potential, and promoted tumor cell apoptosis, showing a better induction effect on mitochondrial dysfunction. In vivo imaging and antitumor experiments based on MDA-MB-231-tumor-bearing nude mice showed that Cst@HA/TPP-M facilitated drug enrichment at the tumor site, attenuated drug systemic distribution, and polished up the antitumor efficacy of Cst compared with free Cst. In general, as a target drug delivery system, mixed micelles co-constructed by TPP-Chol and HA-Chol might provide a promising strategy to ameliorate the therapeutic outcomes of Cst on TNBC.

TBC1 domain-containing proteins are frequently involved in triple-negative breast cancers in connection with the induction of a glycolytic phenotype

Metabolic plasticity is a hallmark of cancer, and metabolic alterations represent a promising therapeutic target. Since cellular metabolism is controlled by membrane traffic at multiple levels, we investigated the involvement of TBC1 domain-containing proteins (TBC1Ds) in the regulation of cancer metabolism. These proteins are characterized by the presence of a RAB-GAP domain, the TBC1 domain, and typically function as attenuators of RABs, the master switches of membrane traffic. However, a number of TBC1Ds harbor mutations in their catalytic residues, predicting biological functions different from direct regulation of RAB activities. Herein, we report that several genes encoding for TBC1Ds are expressed at higher levels in triple-negative breast cancers (TNBC) vs. other subtypes of breast cancers (BC), and predict prognosis. Orthogonal transcriptomics/metabolomics analysis revealed that the expression of prognostic TBC1Ds correlates with elevated glycolytic metabolism in BC cell lines. In-depth investigations of the three top hits from the previous analyses (TBC1D31, TBC1D22B and TBC1D7) revealed that their elevated expression is causal in determining a glycolytic phenotype in TNBC cell lines. We further showed that the impact of TBC1D7 on glycolytic metabolism of BC cells is independent of its known participation in the TSC1/TSC2 complex and consequent downregulation of mTORC1 activity. Since TBC1D7 behaves as an independent prognostic biomarker in TNBC, it could be used to distinguish good prognosis patients who could be spared aggressive therapy from those with a poor prognosis who might benefit from anti-glycolytic targeted therapies. Together, our results highlight how TBC1Ds connect disease aggressiveness with metabolic alterations in TNBC. Given the high level of heterogeneity among this BC subtype, TBC1Ds could represent important tools in predicting prognosis and guiding therapy decision-making.

Nanodynamo quantifies subcellular RNA dynamics revealing extensive coupling between steps of the RNA life cycle

The coordinated action of transcriptional and post-transcriptional machineries shapes gene expression programs at steady state and determines their concerted response to perturbations. We have developed Nanodynamo, an experimental and computational workflow for quantifying the kinetic rates of nuclear and cytoplasmic steps of the RNA life cycle. Nanodynamo is based on mathematical modelling following sequencing of native RNA from cellular fractions and polysomes. We have applied this workflow to triple-negative breast cancer cells, revealing widespread post-transcriptional RNA processing that is mutually exclusive with its co-transcriptional counterpart. We used Nanodynamo to unravel the coupling between transcription, processing, export, decay and translation machineries. We have identified a number of coupling interactions within and between the nucleus and cytoplasm that largely contribute to coordinating how cells respond to perturbations that affect gene expression programs. Nanodynamo will be instrumental in unravelling the determinants and regulatory processes involved in the coordination of gene expression responses.

Proteomic analysis reveals the dominant effect of ipomoeassin F on the synthesis of membrane and secretory proteins in triple-negative breast cancer cells.

Ipomoeassin F (Ipom-F) is a natural compound with embedded carbohydrates that exhibits a potent cytotoxic effect on triple-negative breast cancer (TNBC) cells. The mechanism behind this selective potency remains unclear. To elucidate this mechanism, we analyzed the proteome profiles of the TNBC MDA-MB-231 cells after exposure to Ipom-F at different time points and increasing doses using a quantitative proteomic method. Our proteomic data demonstrate that the major effect of Ipom-F on MDA-MB-231 cells is the inhibition of membrane and secreted protein expression. Our proteomic data are consistent with the recently uncovered molecular mechanism of action of Ipom-F, which binds to Sec61-α and inhibits the co-translational import of proteins into the endoplasmic reticulum. We have defined a subset of membrane and secreted proteins particularly sensitive to Ipom-F. Analysis of the expression of these Ipom-F-sensitive proteins in cancer cell lines and breast cancer tissues demonstrates that some of these proteins are upregulated in TNBC cells. Thus, it is likely that TNBC cells may have adapted to the elevated levels of some proteins identified as sensitive to Ipom-F in this study; inhibition of the expression of these proteins leads to a crisis in proliferation and/or survival for the cells.

Cannabidiol enhances Atezolizumab efficacy by upregulating PD-L1 expression via the cGAS-STING pathway in triple-negative breast cancer cells.

The treatment of patients with triple negative breast cancer (TNBC) relies on cytotoxic therapy. Currently, atezolizumab and chemotherapy can be combined in patients with TNBC. However, this approach is not effective for all patients with low reactivity to atezolizumab. As there is a lack of alternative treatment options, new anti-cancer drugs are urgently needed to enhance atezolizumab reactivity against TNBC. Recent strategies have focused on regulating the expression of programmed death-ligand 1 (PD-L1) or enhancing immune response activation by combining anti-cancer drugs with immune checkpoint inhibitors (ICIs). Cannabidiol (CBD), a cannabinoid component derived from the cannabis plant, has been reported to have anti-cancer therapeutic potential because of its capacity to induce apoptotic cell death in tumor cells while avoiding cytotoxicity in normal cells. Previous studies have demonstrated the effects of CBD on apoptosis in various cancer cell types. However, the potential role of CBD as an immune modulator in the regulation of PD-L1 expression and anti-cancer immune responses remains to be explored. In this study, we found that CBD stimulated PD-L1 expression in TNBC cells, which significantly induced the CBD-mediated cGAS-STING pathway activation. Taken together, we demonstrated that the combination of CBD and anti-PD-L1 antibody enhances the anti-cancer immune response in vitro and in vivo experiments. Our findings identified the mechanism of PD-L1 regulation by CBD in TNBC cells and suggested that CBD could be a potential candidate for the development of new combinatorial strategies with ICIs in TNBC patients.

Decreased Autophagic Activity in Triple-Negative Breast Cancer Cells upon Hydroxychloroquine and Thymoquinone Combination Treatment

Objective: Autophagy plays a significant role in breast cancer tumorigenesis, including triple-negative breast cancer. Research indicates that hydroxychloroquine and thymoquinone modulate autophagy, potentially suppressing its activity. However, their combined effects on autophagy in triple-negative breast cancer remain unexplored. In this study, we investigated the potential anti-cancer and autophagy-modulating effects of hydroxychloroquine-thymoquinone combination on triple-negative breast cancer cells in vitro. Material and Method: The viability of MDA-MB-231 cells was evaluated after treatment with hydroxychloroquine (10-210 µM) and thymoquinone (5-45 µM) for 24 and 48 hours using the WST-1 assay. Combination effects were analyzed using the Chou-Talalay method with CompuSyn (v.10). Autophagic vesicles were visualized using an Autophagy Detection Kit and fluorescence microscopy to investigate their role in the decrease in cell viability. Statistical analysis was performed with GraphPad Prism (v.8.3.0). Results: At both 24- and 48-hour intervals post-treatment, a significant decrease in viability was observed for both hydroxychloroquine and thymoquinone treatments individually (p1). At 24 hours, favorable dose reduction effects were evident (dose reduction index &gt;1), while the 48-hour results showed an unfavorable reduction (dose reduction index

Beauvericin Reverses Epithelial-to-Mesenchymal Transition in Triple-Negative Breast Cancer Cells through Regulation of Notch Signaling and Autophagy.

Metastasis stands as a prime contributor to triple-negative breast cancer (TNBC) associated mortality worldwide, presenting heightened severity and significant challenges due to limited treatment options. Addressing TNBC metastasis necessitates innovative approaches and novel therapeutics to specifically target its propensity for dissemination to distant organs. Targeted therapies capable of reversing epithelial-to-mesenchymal transition (EMT) play a crucial role in suppressing metastasis and enhancing the treatment response. Beauvericin, a promising fungal secondary metabolite, exhibits significant potential in diminishing the viability of EMT-induced TNBC cells by triggering intracellular oxidative stress, as evidenced by an enhanced reactive oxygen species level and reduced mitochondrial transmembrane potential. In monolayer cultures, it has exhibited an IC50 of 2.3 μM in both MDA-MB-468 and MDA-MB-231 cells, while in 3D spheroids, the IC50 values are 9.7 and 7.1 μM, respectively. Beauvericin has also reduced the migratory capability of MDA-MB-468 and MDA-MB-231 cells by 1.5- and 1.7-fold, respectively. Both qRT-PCR and Western blot analysis have shown significant upregulation in the expression of epithelial marker (E-cadherin) and downregulation in the expression of mesenchymal markers (N-cadherin, vimentin, Snail, Slug, and β-catenin), following treatment, indicating reversal of EMT. Furthermore, beauvericin has suppressed the Notch signaling pathway by substantially downregulating Notch-1, Notch-3, Hes-1, and cyclinD3 expression and induced autophagy as observed by elevated expression of autophagy markers LC3 and Beclin-1. In conclusion, beauvericin has successfully downregulated TNBC cell survival by inducing oxidative stress and suppressed their migratory potential by reversing EMT through the inhibition of Notch signaling and activation of autophagy.