Activity In Triple-negative Breast Cancer Research Articles

In vitro study on anti-proliferative and anti-cancer activity of picrosides in triple-negative breast cancer.

Picrorhiza kurroa, an "Indian gentian," a known Himalayan medicinal herb with rich source of phytochemicals like picrosides I, II, and other glycosides, has been traditionally used for the treatment of liver and respiratory ailments. Picrosides anti-proliferative, anti-oxidant, anti-inflammatory and other pharmacological properties were evaluated in treating triple-negative breast cancer (TNBC). Picroside I and II were procured from Sigma-Aldrich and were analyzed for anti-cancer activity in triple-negative breast cancer (MDA-MB-231) cells. Cell viability was analyzed using MTT and trypan blue assays. Apoptosis was analyzed through DNA fragmentation and Annexin V/PI flow cytometric analysis. Wound healing and cell survival assays were employed to determine the inhibition of invasion capacity and anti-proliferative activity of picrosides in MDA-MB-231 cells. Measurement of intracellular ROS was studied through mitochondrial membrane potential assessment using DiOC6 staining for anti-oxidant activity of picrosides in MDA-MB-231 cells. Both Picroside I and II have shown decreased cell viability of MDA-MB-231 cells with increasing concentrations. IC50 values of 95.3µM and 130.8µM have been obtained for Picroside I and II in MDA-MB-231 cells. Early apoptotic phase have shown an increase of 20% (p < 0.05) with increasing concentrations (0, 50, 75, and 100µM) of Picroside I and 15% (p < 0.05) increase with Picroside II. Decrease in mitochondrial membrane potential of 2-2.5-fold (p < 0.05) was observed which indicated decreased reactive oxygen species (ROS) generation with increasing concentrations of Picroside I and II. An increasing percentage of 70-80% (p < 0.05) cell population was arrested in G0/G1 phase of cell cycle after Picroside I and II treatment in cancer cells. Our results suggest that Picroside I and II possess significant anti-proliferative and anti-cancer activity which is mediated by inhibition of cell growth, decreased mitochondrial membrane potential, DNA damage, apoptosis, and cell cycle arrest. Therefore, Picroside I and II can be developed as a potential anti-cancer drug of future and further mechanistic studies are underway to identify the mechanism of anti-cancer potential.

Abstract PO5-06-07: Unravelling the role of PKC-eta in modulating the Hippo Pathway: a novel therapeutic strategy for triple-negative breast cancer metastasis

Abstract Breast cancer (BC) is the leading cause of cancer-related deaths in women, with metastasis being the primary reason for BC mortality. Triple-Negative Breast Cancer (TNBC) is aggressive and highly metastatic, having fewer treatment options than other types of breast cancer. Protein kinase C eta (PKCη), an anti-apoptotic kinase of the novel PKC subfamily, is associated with poor prognosis in invasive BC patients. In this study, we show the role of PKCη in promoting cell migration and invasion, and we demonstrate that its expression is required to maintain the mesenchymal state during EMT. Furthermore, we show that PKCη activates YAP/TAZ, tumor aggressiveness, and metastasis using in vitro and in vivo models. PKCη promotes metastasis in TNBC cells, showing that the PKCƞ-YAP signaling axis mediates this. Data analysis of BC patients with a high metastatic invasive propensity and low survival BC revealed a positive correlation between the elevated expression levels of PKCη and the expression of YAP. Knockout of PKCη (PKCηKO) in the TNBC cells 4T1 and MDA-MB-231 markedly inhibited their invasion and migration capability. We further show that PKCη enhances cell survival and anoikis prevention ability, which have crucial roles in metastasis formation, allowing cancer cells to circulate and home to distant sites in the body. Further substantiated by in vivo experiments with 4T1 xenografts in NSG mice, demonstrating that 4T1 PKCηKO cells depicted reduced primary tumor size and a significant decrease in size and number of tumor metastases in the lungs, with fewer tumor nodules. MDA-MB-231 PKCηKO xenografts also expressed reduced metastasis in the distant brain, lung, and liver organs. Mechanistically, we show that PKCη regulates epithelial-to-mesenchymal transition (EMT) markers as knockout of PKCη in TNBC cell lines increased expression of E-cadherin, EpCAM, and slug, and decreased expression of vimentin and ZEB1. Further profiling of the Hippo-YAP axis showed that PKCη is a negative regulator of the Hippo pathway that leads to YAP stabilization and is associated with phosphorylation at Ser128, which allows YAP to translocate to the nucleus and contributes to metastasis of TNBC cells. Moreover, our data support direct interaction between PKCη and YAP1 in TNBC cells. Finally, we show that treatment of TNBC cells with uPEP2 (a uORF-encoded peptide of the PKCη transcript) downregulates the PKCη expression, activates the Hippo signaling pathway and promotes YAP degradation. Our findings highlight the importance of PKCη in TNBC metastasis and provide a new avenue for therapeutic intervention in this aggressive and lethal disease. In conclusion, our studies identify a novel role of PKCη as a negative regulator of the Hippo pathway and reveal its function in promoting EMT and metastasis by modulating YAP/TAZ activity in TNBC. Results suggest that PKCη may represent a therapeutic target for this highly lethal and metastatic TNBC. Citation Format: Liju Vijaya Steltar Belsamma, Amitha Muraleedharan, Divya Ram Jayaram, Kamran Waidha, Sankar Jagadeeshan, Rose Sinay, Ekaterina Eremenko, Omer Berner, Moshe Elkabets, Etta Livneh. Unravelling the role of PKC-eta in modulating the Hippo Pathway: a novel therapeutic strategy for triple-negative breast cancer metastasis [abstract]. In: Proceedings of the 2023 San Antonio Breast Cancer Symposium; 2023 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2024;84(9 Suppl):Abstract nr PO5-06-07.

Abstract 4549: Combinations of ciclopirox olamine and metformin exert synergistic antitumor activity in triple-negative breast cancer

Abstract Introduction: Triple-negative breast cancer (TNBC) represents a challenging subtype of breast cancer because of its limited treatment options. Recent research has highlighted the potential benefits of combining pharmacological agents to enhance therapeutic outcomes. Studies show that Ciclopirox olamine (CPX), an off-patent anti-fungal drug, induces cell cycle G1-phase arrest and activates the intrinsic apoptosis pathway by downregulating the anti-apoptotic proteins. Meanwhile, metformin, a safe and first-line drug for the treatment of type II diabetes, has been shown to induce cell cycle S-phase arrest and activates the extrinsic apoptosis pathway via induction of endogenous TRAIL in TNBC cells. However, whether the combinations of CPX and metformin would exert potent antitumor activity against TNBC remains unclear. Methods: Cell proliferation (MTS) assays and LIVE/DEAD cell imaging were used to determine the combined inhibitory effects on TNBC cells. IC50s and the combination index (CI) were calculated. Flow cytometry assays were carried out to analyze if the combinations are more potent to block cell cycle progression. Apoptotic-specific ELISA and flow cytometry analysis of Annexin V-PI staining were performed to assess if the combinations are significantly more effective to induce apoptosis. Western blot assays were used to examine if the combinations markedly induced the expression of TRAIL and cleavages of PARP and caspases. Tumor xenograft models will be established to test the in vivo antitumor activity of CPX and metformin either alone or in combinations. Results: Data indicated that both CPX and metformin independently inhibited the proliferation of TNBC cells. A synergistic effect was observed when CPX and metformin were used in combination, resulting in a more potent inhibition of TNBC cell proliferation. The combinatorial treatment effectively suppressed colony formation of TNBC cells. Synergy between CPX and metformin was partially linked to the enhanced activation of the AMPK-mTOR pathway, as the combination significantly enhanced the phosphorylation of AMPKα. The combinations also induced enhanced apoptosis in TNBC cells through both the intrinsic and extrinsic pathways. The combinatorial effects of CPX and metformin on in vivo tumor growth are under investigation. Conclusions: Combinations of CPX and metformin show synergistic effects on inhibiting TNBC cell proliferation. Our studies suggest a potential therapeutic strategy for TNBC, with the combinations of these agents exhibiting an enhanced antitumor activity. Further investigation is warranted to validate the results and explore their clinical applications. Key words: Triple-negative breast cancer, Ciclopirox olamine, Metformin, Combination, Apoptosis Citation Format: Yakun Wu, Hui Lyu, Congcong Tan, Margaret E. Larsen, Shile Huang, Bolin Liu. Combinations of ciclopirox olamine and metformin exert synergistic antitumor activity 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 4549.

Abstract 4208: In-vitro modeling of Sonic Hedgehog signaling identifies the extracellular matrix as a regulator of tumor invasion outcomes

Abstract Preclinical models of Sonic Hedgehog (SHH)-driven tumors support the therapeutic benefit of pharmacological inhibitors, yet clinical outcomes are conflicted due to biphasic tumor responses that include complete remission or faster disease progression. In such studies, the activity of the SHH pathway in the tumor-adjacent stroma supported or restrained tumor progression. Our prior studies show that altered SHH ligand levels can lead to faster tumor growth during pharmacological inhibition suggesting a role for the SHH pathway strength in the biphasic tumor responses of a triple-negative breast cancer (TNBC) model. In this study, the role of SHH pathway strength altered by tumor-fibroblast proximity was examined on the tumor growth, invasion, and transcriptional activity using in vitro and in vivo models. Tumor spheroid models composed of TNBC cell lines and fibroblasts were used to monitor SHH signal strength as a function of the culture modality and SHH ligand levels. In vitro, SHH signal strength was altered by tumor-fibroblast proximity and ligand concentration. Mixed cultures exhibited significantly higher SHH activity and reduced invasion than adjacent cultures. This effect was reversed by pharmacological inhibition of SMO, confirming the involvement of an SHH-dependent mechanism. In a tumor xenograft model, tumor metastasis outcomes were suppressed by pharmacological inhibition of the SHH pathway, but opposite results were observed in tumor xenografts composed of co-injected with fibroblasts indicating that the biphasic tumor response can be driven by the fibroblasts. Spatial transcriptional analysis identified extracellular matrix (ECM) activities in fibroblasts as the top altered bioprocesses in both in vitro and in vivo. This finding was confirmed in cultures, where fibroblast-derived decellularized matrix stimulated tumor invasion of single TNBC spheroids at levels observed in co-cultures. Further analysis of differentially expressed genes (DEGs) identified a small leucine-rich repeat proteoglycan (SLRP) as the primary ECM target altered by variations in SHH signal strength in fibroblasts. Furthermore, we confirmed the role of SLRP cues in governing tumor invasion potency within spheroid cultures embedded in a collagen hydrogel matrix. While high levels of SLRP in the matrix inhibited spheroid invasion, low SLRP matrix promoted spheroid invasion and increased secondary invasion sites. These findings agreed with the Vimentin expression levels observed in TNBC cells and confirmed the potency of SLRP in regulating tumor invasion outcomes. In summary, our study underscores the significance of ECM remodeling activities in fibroblasts and the role of SLRPs in governing tumor invasion, with implications for understanding the impact of altering SHH signaling activity in TNBC. Citation Format: Emanuel A. Carrasquillo-Dones, Heizel M. Rosado-Galindo, Ana M. Reyes-Ramos, Wandaliz Torres-Garcia, Said Cifuentes, Jan P. Rios-Grant, Gabriela Ortiz-Soto, Natalia A. Ramos-Acevedo, Miosotis Acevedo-Esquilin, Monica Colon-Vargas, Israel Almodovar-Rivera, Camilo Mora, Michelle M. Martinez-Montemayor, Maribella Domenech. In-vitro modeling of Sonic Hedgehog signaling identifies the extracellular matrix as a regulator of tumor invasion outcomes [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 4208.

Abstract A154: PDLIM2 is required for regulating inflammation and cellular redox levels in mouse colorectal epithelial model

Abstract PDLIM2 is a cytoskeletal and nuclear protein present in hematopoietic and epithelial cells that regulates cell differentiation and the protein stability of transcription factors including NF-κB, STATs, and β-catenin (1). PDLIM2 expression is repressed in certain cancers, but is highly expressed in cancer cells that exhibit a metastatic phenotype (2). PDLIM2 is also highly expressed in the tumour microenvironment of breast cancer, particularly in the pro-wound healing M2 macrophage population. In line with this, bone-marrow derived macrophages from PDIM2 knockout (KO) mice have impaired differentiation towards the M2 macrophage phenotype (3). Here we investigated the effects of PDLIM2 loss in epithelial and immune cells in a colitis-associated cancer model using PDLIM2 wild type (WT) and KO mice exposed to dextran sodium sulphate (DSS) and azoxymethane (AOM). We observed that PDLIM2 KO mice exhibited a strong response to DSS alone. Colon tissue from DSS-treated mice exhibited impaired epithelium repair, sustained inflammation, and low levels of wound-healing M2 macrophages compared to WT tissues. To address the molecular mechanisms associated with PDLIM2 KO in colon epithelial cells, we suppressed or knocked out PDLIM2 in the Caco2 cell line. Caco-2 cells lacking PDLIM2 displayed dysregulated adhesion signalling, which was accompanied by elevated levels of reactive oxygen species (ROS), mitochondrial dysfunction and increased dependence on glycolysis. Overall, we conclude that PDLIM2 is required for the resolution of inflammation and to promote intestinal epithelial repair through regulating cell adhesion signalling and cellular redox balance. 1. Guo ZS, Qu Z. PDLIM2: Signaling pathways and functions in cancer suppression and host immunity. Biochim Biophys Acta Rev Cancer. 2021 Dec;1876(2):188630. doi: 10.1016/j.bbcan.2021.188630. 2. Cox OT, Edmunds SJ, Simon-Keller K, Li B, Moran B, Buckley NE, Bustamante-Garrido M, Healy N, O'Flanagan CH, Gallagher WM, Kennedy RD, Bernards R, Caldas C, Chin SF, Marx A, O'Connor R. PDLIM2 Is a Marker of Adhesion and β-Catenin Activity in Triple-Negative Breast Cancer. Cancer Res. 2019 May 15;79(10):2619-2633. doi: 10.1158/0008-5472.CAN-18-2787. 3. Cox OT, O'Sullivan N, Tresse E, Ward S, Buckley N, O'Connor R. PDLIM2 is highly expressed in Breast Cancer tumour-associated macrophages and is required for M2 macrophage polarization. Front Oncol. 2022 Nov 30;12:1028959. doi: 10.3389/fonc.2022.1028959. Citation Format: Stephanie Ward, Silvia Melgar, Orla T Cox, Raffaella Morelli, Rosemary O'Connor. PDLIM2 is required for regulating inflammation and cellular redox levels in mouse colorectal epithelial model [abstract]. In: Proceedings of the AACR-NCI-EORTC Virtual International Conference on Molecular Targets and Cancer Therapeutics; 2023 Oct 11-15; Boston, MA. Philadelphia (PA): AACR; Mol Cancer Ther 2023;22(12 Suppl):Abstract nr A154.

Fucoidan-mediated targeted delivery of dasatinib-loaded nanoparticles amplifies apoptosis and endows cytotoxic potential in triple-negative breast cancer

Dasatinib (DST) is a tyrosine kinase inhibitor with established antiproliferative activity in Triple-negative breast cancer. Conventional treatment strategies with DST have several pitfalls related to the development of resistance, lower cellular uptake and unwanted adverse effects. To address these issues, we have prepared P-selectin-targeted nanoparticles of DST with fucoidan (FUC) as a ligand. Poly lactide-co-glycolide nanoparticles of DST were coated with chitosan (CH) and FUC via electrostatic interaction (DST-CH-FUC-NPs). The mean particle size of 210.36 ± 0.66 nm and a polydispersity index of 0.234 ± 0.013 was observed for DST-CH-FUC-NPs. TEM and FTIR analysis proved CH coating followed by an FUC layer on nanoparticles. DST-CH-FUC-NPs showed a sustained release profile up to 120 h and 2.9 times less hemolytic potential than free DST suspension. DST-CH-FUC-NPs demonstrated 8-fold higher cytotoxicity compared to free DST in MDA-MB-231 cells. Rhodamine-CH-FUC- NPs showed 19 times and 3 times higher cellular uptake than free Rhodamine and Rhodamine-CH-NPs, respectively. DST-CH-FUC-NPs also displayed increased ROS production and mitochondrial membrane potential damage. Apoptosis study revealed a 7.5-fold higher apoptosis index for DST-CH-FUC-NPs than free DST. Subsequently, the DST-CH-FUC-NPs showed increased inhibition of cell migration, where approximately 5 % wound closure was noted. Further, DST-CH-FUC-NPs confirmed higher disruption of lysosomal membrane integrity, which is well correlated with apoptosis results. In addition, developed NPs were nontoxic on MCF 10 A normal cells. All these findings suggest that fabricated DST-CH-FUC-NPs are promising biocompatible carriers for tumor-targeted delivery and enhanced efficacy of dasatinib.

Pimavanserin tartrate induces apoptosis and cytoprotective autophagy and synergizes with chemotherapy on triple negative breast cancer

Triple negative breast cancer (TNBC) poses a significant clinical challenge due to its lack of targeted therapy options and the frequent development of chemotherapy resistance. Metastasis remains a primary cause of mortality in late-stage TNBC patients, underscoring the urgent need for alternative treatments. Repurposing existing drugs offers a promising strategy for the discovery of novel therapies. In this study, we investigated the potential of pimavanserin tartrate (PVT) as a treatment for TNBC. While previous studies have highlighted PVT's anticancer effects in various cancer types, its activity in TNBC remains unclear. Our investigation aimed to elucidate the anticancer effects and underlying mechanisms of PVT in TNBC. We evaluated the impact of PVT and combination treatments involving PVT on TNBC cell viability, apoptosis, autophagy, and associated signaling pathways. Our findings revealed that PVT may induce mitochondria-dependent intrinsic apoptosis and caused cytoprotective autophagy via the PI3K/Akt/mTOR pathway in TNBC cells in vitro. Notably, our study demonstrated strong synergistic anti-TNBC effects when combining PVT with doxorubicin. We also found PVT showed some efficacies to inhibit TNBC tumor growth in vivo. These results provided valuable insights into the potential of PVT as an anti-TNBC therapeutic and a possible option for enhancing the sensitivity of TNBC cells to conventional chemotherapy drugs. Further studies are needed to determine the activity and mechanism of PVT in inhibiting TNBC.

SP1-Induced Upregulation of LncRNA AFAP1-AS1 Promotes Tumor Progression in Triple-Negative Breast Cancer by Regulating mTOR Pathway.

The long non-coding RNA (lncRNA) actin fiber-associated protein-1 antisense RNA 1 (AFAP1-AS1) exerted oncogenic activity in triple-negative breast cancer (TNBC). We designed this study and conducted it to investigate the upstream regulation mechanism of AFAP1-AS1 in TNBC tumorigenesis. In this work, we proved the localization of AFAP1-AS1 in the cytoplasm. We elucidated the mechanism by which the transcription factor specificity protein 1 (SP1) modulated AFAP1-AS1 in TNBC progression, which has yet to be thoroughly studied. Dual luciferase reporter assay and chromatin immunoprecipitation (ChIP) assay revealed a strong affinity of SP1 toward the promoter regions P3 of AFAP1-AS1, proving the gene expression regulation of AFAP1-AS1 via SP1 in TNBC. Additionally, SP1 could facilitate the tumorigenesis of TNBC cells in vitro and in vivo by regulating the AFAP1-AS1 expression. Furthermore, silenced AFAP1-AS1 suppressed the expression of genes in the mTOR pathway, such as eukaryotic translation initiation factor 4B (EIF4B), mitogen-activated protein kinase-associated protein 1 (MAPKAP1), SEH1-like nucleoporin (SEH1L), serum/glucocorticoid regulated kinase 1 (SGK1), and its target NEDD4-like E3 ubiquitin protein ligase (NEDD4L), and promoted the gene expression of s-phase kinase-associated protein 2 (SKP2). Overall, this study emphasized the oncogenic role of SP1 and AFAP1-AS1 in TNBC and illustrated the AFAP1-AS1 upstream interaction with SP1 and the downstream modulatory of mTOR signaling, thus offering insights into the tumorigenesis mechanism in TNBC.

Targeting FAK/PYK2 with SJP1602 for Anti-Tumor Activity in Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) presents significant challenges due to its aggressive nature and limited treatment options. Focal adhesion kinase (FAK) has emerged as a critical factor promoting tumor growth and metastasis in TNBC. Despite encouraging results from preclinical and early clinical trials with various FAK inhibitors, none have yet achieved clinical success in TNBC treatment. This study investigates the therapeutic potential of a novel dual inhibitor of FAK and PYK2, named SJP1602, for TNBC. In vitro experiments demonstrate that SJP1602 effectively inhibits FAK and PYK2 activities, showing potent effects on both kinases. SJP1602 shows concentration-dependent inhibition of cell growth, migration, invasion, and 3D spheroid formation in TNBC cell lines, surpassing the efficacy of other FAK inhibitors. Pharmacokinetic studies in rats indicate favorable bioavailability and sustained plasma concentrations of SJP1602, supporting its potential as a therapeutic agent. Furthermore, in TNBC xenograft models, SJP1602 exhibits significant dose-dependent inhibition of tumor growth. These promising results emphasize the potential of SJP1602 as a potent dual inhibitor of FAK and PYK2, deserving further investigation in clinical trials for TNBC treatment.

Natural-Product-Derived Adjunctive Treatments to Conventional Therapy and Their Immunoregulatory Activities in Triple-Negative Breast Cancer.

Triple-negative breast cancer (TNBC) is an invasive and persistent subtype of breast cancer that is likely to be resistant to conventional treatments. The rise in immunotherapy has created new modalities to treat cancer, but due to high costs and unreliable efficacy, adjunctive and complementary treatments have sparked interest in enhancing the efficacy of currently available treatments. Natural products, which are bioactive compounds derived from natural sources, have historically been used to treat or ameliorate inflammatory diseases and symptoms. As TNBC patients have shown little to no response to immunotherapy, the potential of natural products as candidates for adjuvant immunotherapy is being explored, as well as their immunomodulatory effects on cancer. Due to the complexity of TNBC and the ever-changing tumor microenvironment, there are challenges in determining the feasibility of using natural products to enhance the efficacy or counteract the toxicity of conventional treatments. In view of technological advances in molecular docking, pharmaceutical networking, and new drug delivery systems, natural products show promise as potential candidates in adjunctive therapy. In this article, we summarize the mechanisms of action of selected natural-product-based bioactive compounds and analyze their roles and applications in combination treatments and immune regulation.

Dose escalation and expansion cohorts in patients with advanced breast cancer in a Phase I study of the CDK7-inhibitor samuraciclib

Samuraciclib is a selective oral CDK7-inhibitor. A multi-modular, open-label Phase I study to evaluate safety and tolerability of samuraciclib in patients with advanced malignancies was designed (ClinicalTrials.gov: NCT03363893). Here we report results from dose escalation and 2 expansion cohorts: Module 1A dose escalation with paired biopsy cohort in advanced solid tumor patients, Module 1B-1 triple negative breast cancer (TNBC) monotherapy expansion, and Module 2A fulvestrant combination in HR+/HER2− breast cancer patients post-CDK4/6-inhibitor. Core study primary endpoints are safety and tolerability, and secondary endpoints are pharmacokinetics (PK), pharmacodynamic (PD) activity, and anti-tumor activity. Common adverse events are low grade nausea, vomiting, and diarrhea. Maximum tolerated dose is 360 mg once daily. PK demonstrates dose proportionality (120 mg-480 mg), a half-life of approximately 75 hours, and no fulvestrant interaction. In dose escalation, one partial response (PR) is identified with disease control rate of 53% (19/36) and reduction of phosphorylated RNA polymerase II, a substrate of CDK7, in circulating lymphocytes and tumor tissue. In TNBC expansion, one PR (duration 337 days) and clinical benefit rate at 24 weeks (CBR) of 20.0% (4/20) is achieved. In combination with fulvestrant, 3 patients achieve PR with CBR 36.0% (9/25); in patients without detectable TP53-mutation CBR is 47.4% (9/19). In this study, samuraciclib exhibits tolerable safety and PK is supportive of once-daily oral administration. Clinical activity in TNBC and HR+/HER2-breast cancer post-CDK4/6-inhibitor settings warrants further evaluation.

Codelivery of triptolide and IFN-γ to boost antitumor immunity for triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a specific type of breast cancer that exhibits poor prognosis and complex tumor heterogeneity. The unique immune tumor microenvironment reveals great potential of immunotherapy in TNBC. Triptolide, a potential regulator of immune-related signaling, has shown potent antitumor activity in TNBC. However, the molecular mechanism of triptolide in TNBC is still controversial. This study identified interferon-γ (IFN-γ) as a therapeutical target of triptolide based on the analysis of prognostic biomarkers in TNBC. IFN-γ is an important component of immunotherapy and contributes to antitumor immune activation. Triptolide was found to significantly reverse the IFN-γ-inducible programmed death-ligand 1 (PD-L1) in TNBC. The combined treatment of triptolide and IFN-γ in a hydrogel delivery system remarkably induced the cytotoxic CD8 + T lymphocytes activation, showing a synergistic effect on the potent tumor inhibition.

Abstract P4-08-23: ZHX2 promotes HIF1α oncogenic signaling in triple-negative breast cancer

Abstract Background: Triple-negative breast cancer (TNBC) is an aggressive and highly lethal disease in women, while the oncogenic mechanisms which contribute to TNBC development, progression, and metastasis are poorly investigated and therefore warrant the critical need to identify novel oncogenic signalings and develop new therapeutic targets. Results: We show that Zinc Fingers and Homeoboxes 2 (ZHX2) is amplified or overexpressed in TNBC cell lines and patients. Functionally, depletion of ZHX2 inhibited TNBC cell growth and invasion in vitro, orthotopic tumor growth, and spontaneous lung metastasis in vivo. Mechanistically, ZHX2 bound with hypoxia-inducible factor (HIF) family members and positively regulated HIF1α protein level and activity in TNBC. Integrated ChIP-seq and gene expression profiling demonstrated that ZHX2 co-occupied with HIF1α on transcriptionally active promoters marked by H3K4me3 and H3K27ac, thereby promoting gene expression. Among the identified ZHX2 and HIF1α coregulated genes, overexpression of AP2B1, COX20, KDM3A, or PTGES3L could partially rescue TNBC cell growth defect by ZHX2 depletion, suggesting that these downstream targets contribute to the oncogenic role of ZHX2 in an accumulative fashion. Furthermore, multiple residues (R491, R581, and R674) on ZHX2 are important in regulating its phenotype, which correspond with their roles in controlling ZHX2 transcriptional activity in TNBC cells. These studies establish that ZHX2 activates oncogenic HIF1α signaling, therefore serving as a potential therapeutic target for TNBC. Conclusion: ZHX2 has been highlighted as one critical hypoxia-related factors regulator contributing to triple-negative breast cancer in this work, which has enriched the upstream regulatory network of HIF-1α signaling. Moreover, identification of key residuals determining biological function of ZHX2 provides novel approaches for treating TNBC via targeting the hypoxia pathway. Citation Format: Chengheng Liao, Wentong Fang, Rachel Shi, Jeremy Simon, Travis Ptacek, Giada Zurlo, Youqiong Ye, Leng Han, Cheng Fan, Lei Bao, Christopher Llynard Ortiz, Hong-Rui Lin, Ujjawal Manocha, Weibo Luo, Yan Peng, William Y Kim, Lee-Wei Yang, Qing Zhang. ZHX2 promotes HIF1α oncogenic signaling in triple-negative breast cancer [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P4-08-23.

Abstract P1-04-04: A multiomic approach to the identification of immune signatures of anti-PD1/PDL1 therapy responders in metastatic triple negative breast cancer: new implications in the role of helper T-cell and B-cell interplay

Abstract Introduction Triple negative breast cancer (TNBC) is a heterogeneous breast cancer subtype which continues to portend a particularly poor prognosis compared to other breast cancer subtypes. Immune checkpoint inhibitor (ICI) therapies have emerged as promising options for locally advanced and metastatic TNBC. However, clinical trials have demonstrated mixed results with respect to ICI response. Given varied outcomes and the potential for immune-related adverse events associated with ICIs, there is critical need for identification of accurate biomarkers of response and improved strategies to counteract ICI resistance and/or toxicity. Methods Advanced immunoprofiling of peripheral blood mononuclear cells (PBMCs) and plasma from 7 metastatic TNBC patients with variable responses to anti-PD1 or anti-PDL1 therapy was performed. Samples were analyzed from blood draws obtained: (i) prior to first administration, (ii) while receiving ICI treatment, and (iii) at the time of conformed clinical progression or response to therapy. Response was determined by standard radiological assessment. Immunoprofiling included high parameter flow cytometry, single cell transcriptomics (10x genomics) and secretome analysis (Isoplexis). Single cell RNA profiles from 63,984 cells were analyzed. Results High parameter flow cytometry identified higher circulating levels of a subpopulation of activated CD4+ T cells with a phenotype of CXCR3low CD62Llow CD45RAhigh and CD57high expression in responders versus non-responders. Higher effector function of CD4+ T cells was corroborated by significantly elevated plasma concentrations of IL-2 (p=0.02) and IL-5 (p&amp;lt; 0.0001) among responders. Single cell transcriptomic analysis revealed clusters of B and T cells with distinct activation patterns that were associated with radiographic response. Strikingly, genes involved in B cell activation and T cell-B cell conjugation such as CD81 were found to be highly upregulated among CD4+ T cells from responders. Conclusions Our results are consistent with previous reports describing an association of increased B cell activity in TNBC with improved overall survival. We identified a subpopulation of CD4+ T cells with effector functions consistent with type 2 helper T cells that may not only target cancer cells by direct cytotoxic function, but also promote increased B cell anti-tumor activity. Our study provides insight into specific mechanisms of immune cell interplay that may drive response to ICI therapy. These cell populations and their associated pathways may represent potential biomarkers of response and/or targets for resistance reversal. Citation Format: Avia D. Wilkerson, Patricia A. Rayman, Paul G. Pavicic Jr, Hana Husic, Vladimir Makarov, Ivan Juric, Timothy Chan, Alberto J. Montero, Marcela Diaz-Montero. A multiomic approach to the identification of immune signatures of anti-PD1/PDL1 therapy responders in metastatic triple negative breast cancer: new implications in the role of helper T-cell and B-cell interplay [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P1-04-04.

Coating of chitosan on poly D,L-lactic-co-glycolic acid thymoquinone nanoparticles enhances the anti-tumor activity in triple-negative breast cancer.

Breast cancer is the second most common cancer around the world. Triple-negative breast cancer (TNBC) is characterized by the absence of three receptors: progesterone, estrogen, and human epidermal growth factor-2 receptor (HER2). Various synthetic chemotherapies have gained attention but they caused unwanted side effects. Therefore, some secondary therapies are now becoming famous against this disease. For instance, natural compounds have been extensively researched against many diseases. However, enzymatic degradation and low solubility remain a major concern. To combat these issues, various nanoparticles have been synthesized and optimized from time to time, which increases its solubility and hence therapeutic potential of a particular drug increases. In this study, we have synthesized Poly D,L-lactic-co-glycolic acid (PLGA) loaded thymoquinone (TQ) nanoparticle (PLGA-TQ-NPs) and then coated them by chitosan (CS) (PLGA-CS-TQ-NPs), which was characterized by different methods. Size of non-coated NPs was 105nm with PDI value of 0.3 and the size of coated NPs was 125nm with PDI value of 0.4. Encapsulation efficiency (EE%) and Drug loading (DL%) was found to be 70.5 ± 2.33 and 3.38 for non-coated and 82.3 ± 3.11 and 2.66 for coated NPs respectively. We have also analysed their cell viability against MDA-MB-231 and SUM-149 TNBC cell lines. The resultant, nanoformulations exhibit anti-cancerous activity in a dose and time-dependent manner for MDA-MB-231 and SUM-149 cell lines with an IC50 value of (10.31 ± 1.15, 15.60 ± 1.25, 28.01 ± 1.24) and (23.54 ± 1.24, 22.37 ± 1.25, 35 ± 1.27) for TQ free, PLGA-TQ-NPs and PLGA-CS-TQ-NPs respectively. For the first time, we have developed a nanoformulations of PLGA loaded TQ coated with CS NPs (PLGA-CS-TQ-NPs) against TNBC which led to their enhanced anti-cancerous effects.

BETi enhance ATGL expression and its lipase activity to exert their antitumoral effects in triple-negative breast cancer (TNBC) cells

BackgroundTriple-Negative Breast Cancer (TNBC) is a subtype of breast cancer that differs from other types of breast cancers in the faster spread and worse outcome. TNBC presented limited treatment options. BET (Bromodomain and extra-terminal domain) proteins are epigenetic readers that control the expression of different oncogenic proteins, and their inhibition (BETi) is considered a promising anti-cancer strategy. Recent evidence demonstrated the involvement of BET proteins in regulation of metabolic processes.MethodsMDA-MB231 cells treated with JQ1 followed by RNA-sequencing analysis showed altered expression of lipid metabolic genes; among these, we focused on ATGL, a lipase required for efficient mobilization of triglyceride. Different in vitro approaches were performed to validate the RNA-sequencing data (qRT-PCR, immunofluorescence and flow cytometry). NMR (Nuclear Magnetic Resonance) was used to analyze the lipid reprogramming upon treatment. ATGL expression was determined by immunoblot and qRT-PCR, and the impact of ATGL function or protein knockdown, alone and in combination with BETi, was assessed by analyzing cell proliferation, mitochondrial function, and metabolic activity in TNBC and non-TNBC cells culture models.ResultsTNBC cells treated with two BETi markedly increased ATGL expression and lipolytic function and decreased intracellular lipid content in a dose and time-dependent manner. The intracellular composition of fatty acids (FAs) after BETi treatment reflected a significant reduction in neutral lipids. The short-chain FA propionate entered directly into the mitochondria mimicking ATGL activity. ATGL KD (knockdown) modulated the levels of SOD1 and CPT1a decreasing ROS and helped to downregulate the expression of mitochondrial ß-oxidation genes in favor of the upregulation of glycolytic markers. The enhanced glycolysis is reflected by the increased of the mitochondrial activity (MTT assay). Finally, we found that after BETi treatment, the FoxO1 protein is upregulated and binds to the PNPLA2 promoter leading to the induction of ATGL. However, FoxO1 only partially prompted the induction of ATGL expression by BETi.ConclusionsThe anti-proliferative effect achieved by BETi is helped by ATGL mediating lipolysis. This study showed that BETi altered the mitochondrial dynamics taking advantage of ATGL function to induce cell cycle arrest and cell death.Graphical Schematic representation of BETi mechanism of action on ATGL in TNBC cells. BETi induce theexpression of FoxO1 and ATGL, lowering the expression of G0G2, leading to a switch in metabolic status. Theinduced expression of ATGL leads to increased lipolysis and a decrease in lipid droplet content and bioavailabilityof neutral lipid. At the same time, the mitochondria are enriched with fatty acids. This cellular status inhibits cellproliferation and increases ROS production and mitochondrial stress. Interfering for ATGL expression, theoxidative phenotypic status mildly reverted to a glycolytic status where neutral lipids are stored into lipiddroplets with a consequent reduction of oxidative stress in the mitochondrial.

Combination of palbociclib with navitoclax based-therapies enhances in vivo antitumoral activity in triple-negative breast cancer

Triple-negative breast cancer (TNBC) is a very aggressive subtype of breast cancer with a poor prognosis and limited effective therapeutic options. Induction of senescence, arrest of cell proliferation, has been explored as an effective method to limit tumor progression in metastatic breast cancer. However, relapses occur in some patients, possibly as a result of the accumulation of senescent tumor cells in the body after treatment, which promote metastasis. In this study, we explored the combination of senescence induction and the subsequent removal of senescent cells (senolysis) as an alternative approach to improve outcomes in TNBC patients. We demonstrate that a combination treatment, using the senescence-inducer palbociclib and the senolytic agent navitoclax, delays tumor growth and reduces metastases in a mouse xenograft model of aggressive human TNBC (hTNBC). Furthermore, considering the off-target effects and toxicity derived from the use of navitoclax, we propose a strategy aimed at minimizing the associated side effects. We use a galacto-conjugated navitoclax (nav-Gal) as a senolytic prodrug that can preferentially be activated by β-galactosidase overexpressed in senescent cells. Concomitant treatment with palbociclib and nav-Gal in vivo results in the eradication of senescent hTNBC cells with consequent reduction of tumor growth, while reducing the cytotoxicity of navitoclax. Taken together, our results support the efficacy of combination therapy of senescence-induction with senolysis for hTNBC, as well as the development of a targeted approach as an effective and safer therapeutic opportunity.

Anti-TGF-β/PD-L1 bispecific antibody promotes T cell infiltration and exhibits enhanced antitumor activity in triple-negative breast cancer

BackgroundAgents blocking programmed cell death protein 1/programmed death-ligand 1 (PD-1/PD-L1) have been approved for triple-negative breast cancer (TNBC). However, the response rate of anti-PD-1/PD-L1 is still unsatisfactory, partly due to...

In Vitro Evaluation of NLS-DTX Activity in Triple-Negative Breast Cancer

Cancer is one of the most lethal diseases in the world, and the development and improvement of treatments used in cancer therapies are extremely important for a better quality of life for patients. In view of the current problems in drug administration such as low solubility and adverse effects, the activity of a solid lipid nanoparticle containing docetaxel (SLN-DTX), a drug already used in conventional therapies, was evaluated in a cell line (MDA-MB-231) of one of the most aggressive types of breast cancer with the worst prognosis, triple-negative breast cancer. Viability tests indicated that SLN-DTX has a greater dependence on the treatment dose when compared to the free drug, which indicates a more controlled release of the drug, and both reduced viability by around 50% at a concentration of 1 µg/mL after 72 h. Transmission electron microscopy (TEM) and confocal and light microscopy analyses indicated that after treatment the cells enter a mitotic catastrophe, characteristic of antimitotic drugs that usually make cells progress to death or senescence. Cells treated with both DTX and SLN-DTX showed significant inhibition of mobility, 73.6% and 66.5% when treated with SLN-DTX and DTX, respectively, compared to the 11.4% of the control after 72 h, characteristics that are very relevant in tumor development and progression. SLN-DTX demonstrated its great potential as a nanocarrier by maintaining and improving the drug’s action in the MDA-MB-231 cell line.

Association Between GATA3 and Histopathological and Immunohistochemical Parameters in Early-Infiltrating Breast Carcinomas

This study evaluated the frequency of GATA-binding protein 3 (GATA3) expression in early breast cancer and its relationship with histopathological and immunohistochemical parameters. GATA3 was analysed by immunohistochemistry in histological sections of tumors from 105 female patients, with histological diagnosis of invasive breast carcinoma (BC), at clinical stages I, II and IIIA, who underwent primary surgical treatment. GATA3 nuclear expression was determined as the percentage of positive tumor cells and further categorized as high (positive expression in more than 95% of cells) or non-high (negative or low positive expression in up to 95% of tumor cells). GATA3 expression was analysed according to the patient age, tumor and node pathological stage, histological type, histological and nuclear grade, lymphovascular invasion, and estrogen receptor (ER), progesterone receptor (PR), androgen receptor (AR), human epidermal growth factor 2 (HER2) status, and Ki-67 expression. GATA3 expression was positive in 103 cases (98.1%). High expression was significantly associated with low histological and nuclear grade, positive hormonal receptors, and less proliferative activity based on Ki-67 expression. A prominent feature was that 94.7% of the ER-positive/HER2-negative cases presented high-GATA3 expression, as 94.0% of the tumors showing high-GATA3 were ER-positive. In ER-negative/HER2-positive or ER-negative/HER2- negative, high-GATA3 was present in 25% while 75% were non-high-GATA3 compared with ER-positive/HER2- negative (4.1%) and ER-positive/HER2-positive (20%). Proliferative activity in triple-negative breast cancer tended to be higher among tumors with low-GATA3, irrespective of AR expression. In the group of ER-positive/HER2-negative tumors only three cases were low-GATA3 (85% and 80%), both with high proliferative activity. High GATA3 expression is associated with favorable histopathologic and immunohistochemical BC prognostic factors.