Expression pattern analysis and drug differential sensitivity of cancer-associated fibroblasts in triple-negative breast cancer

Novel Combination Therapy Targeting Oncogenic Signaling Kinase P21-Activated Kinase 1 and Chemotherapeutic Drugs Against Triple-Negative Breast Cancer

Most of the triple-negative phenotypes or basal-like molecular subtypes of breast cancers are associated with aggressive clinical behavior and show poor disease prognosis. Current treatment options are constrained, emphasizing the need for novel combinatorial therapies for this particular tumor subtype. Our group has demonstrated that functionally active p21-activated kinase 1 (PAK1) exhibits significantly higher expression levels in clinical triple-negative breast cancer (TNBC) samples compared with other subtypes, as well as adjacent normal tissues. Low PAK1 expression in TNBC was significantly linked to better prognosis, with improved overall survival (P = 0.00236) and relapse-free survival (P = 0.0314), as shown by Gene expression-based Outcome for Breast cancer Online analysis. To confirm the role of PAK1 as a therapeutic target and to discover novel synergistic chemotherapy drug combinations, we conducted a drug combination screen using TNBC cell lines and a mouse metastatic tumor cell line. We identified the combined inhibition of PAK1 inhibitor NVS-PAK1 with doxorubicin/paclitaxel/methotrexate as a synergistic novel therapeutic approach for treating metastatic TNBC to improve overall survival. This study also indicated a reduction in the effective dosage of the chemotherapeutic drug when combined with NVS-PAK1. Our study demonstrates that combining NVS-PAK1 with each individual chemotherapeutic drug such as doxorubicin, paclitaxel, and methotrexate resulted in decreased colony formation, reduced wound-healing capability, and diminished migratory and invasive potential in both TNBC cell lines and 4T1 in vitro. These findings were further validated in orthotopic mouse mammary tumors, confirming that simultaneous PAK1 inhibition alongside chemotherapy significantly enhanced antitumor efficacy and reduced metastasis.

Mechanoresponsive patterns of KLF2, 4, 5, and 6 expression differ among subclones from a single mammary tumor

A number of Krüppel-like transcription factor (KLF) family members display mechanoresponsive behaviors, and function as mechanosensitive transcription factors. There are many normal and pathological conditions where their roles in mechanotransduction and mechanoadaptation are not well understood, however. In this study, two basic questions regarding KLF mechanoresponsiveness were addressed: 1) are KLF 2, 4, 5, and 6 expressed at different levels among subclones of tumor cells adapted to specific microenvironmental conditions; and 2) is the expression of these KLFs responsive to rapid changes in the physical environment? To address these questions, the heterogeneous and differentially metastatic murine mammary tumor subclones 4T1, 4T07, and 67NR were subjected to physical changes in their culture conditions, and KLF responses assessed. The results show that the expression of different KLFs exhibit distinct responses to reductions in cell tension, as well as cell detachment from 2D and 3D environments. KLF2 and 4 expression is rapidly and temporarily induced upon release of cells from a stiff 2D substrate into liquid suspension culture in all three subclones, and similar responses are observed in two of the subclones upon the release of tension in 3D collagen gel cultures. By contrast, expression patterns of KLF5 and 6 were generally less affected by physical changes in most, but not all, of the cell lines examined. These results support the concept that KLFs differentially participate in transducing physical differences among intratumoral neighborhoods into distinct responses among heterogeneous subclones, thereby contributing to tumor cell behavioral complexity.

Novel heterogeneity method for predicting survival in non-metastatic triple-negative breast cancer

OBJECTIVE

This study aimed to investigate the relationship between semiquantitative positron emission tomography (PET) parameters and intratumoral heterogeneity (ITH) on 18F-fluorodeoxyglucose positron emission tomography/computed tomography (18F-FDG PET/CT) imaging and survival data of non-metastatic triple-negative breast cancer (TNBC) patients.

METHODS

Sixty-two consecutive female patients who underwent pretreatment 18F-FDG PET/CT with non-metastatic TNBC were enrolled. Heterogeneity index (HI) variables derived from the metabolic tumor volume (MTV) and standardized uptake value (SUV) parameters of primary lesions were evaluated. A novel modified method introducing a percentage-based (30-40-50%) MTV slope comparison was proposed. The association between conventional 18F-FDG PET/CT parameters, HI values, and survival results was analyzed retrospectively.

RESULTS

Tumors with higher HI values were associated with shorter survival times. For overall survival (OS), HI2 and HI3 were statistically significant (p=0.009, p=0.016). Regarding radiological progression-free survival (rPFS), HI1 and HI3 were statistically significant (p=0.01, p=0.025). A significant weak correlation between HI1 (p=0.005, ρ=0.34) and a strong correlation was found for HI2 (p<0.0001, ρ=0.89), HI3 and tumor size were not statistically significantly correlated (p=0.063, ρ=0.23). T stage was statistically significantly associated with rPFS and OS ((p=0.038, p=0.003). In contrast, no statistically significant difference was found for the N stage, anatomical, and clinical staging (p>0.05).

CONCLUSION

This study concluded that ITH predicts survival for non-metastatic TNBC patients. This conclusion was reached with the heterogeneity index variables obtained by different methods. However, our results revealed that HI2 depends on tumor size. Our modified method (HI3) predicts survival independently of tumor size.

Soluble TREM2 drives triple-negative breast cancer progression via activation of the AKT pathway

Triggering receptor expressed on myeloid cells 2 (TREM2) plays a key role in immune regulation, particularly within tumor-associated macrophages (TAMs). In triple-negative breast cancer (TNBC), TREM2+ TAMs have been shown to modulate the tumor microenvironment, but the role of its soluble form: soluble triggering receptor expressed on myeloid cells 2 (sTREM2), produced through proteolytic cleavage, remains unclear. In this study, we investigated the effects of sTREM2 on TNBC progression. In vitro, treatment of TNBC cells with recombinant sTREM2 or sTREM2-containing culture supernatant significantly enhanced cell proliferation, invasion, and migration. These effects were further confirmed by the use of TREM2-neutralizing antibodies, which abrogated sTREM2's tumor-promoting activities. In vivo, peri-tumoral injections of recombinant sTREM2 led to a notable acceleration of tumor growth in mouse models. Mechanistically, we found that the effects of sTREM2 were mediated through its binding to the TG2 protein in 4T1 cells, thereby activating the AKT signaling pathway. Collectively, our findings suggest that sTREM2 drives TNBC progression by enhancing critical tumor cell functions, positioning it as a potential therapeutic target for TNBC treatment.

The Relationship of Metabolic Activity and αvβ3 Receptor Expression in Aggressive Breast Cancer Subtypes Tumors: A Preliminary Report

BACKGROUND/AIM

Angiogenesis imaging has been a valuable complement to metabolic imaging with 2-deoxy-2-[18F]fluoroglucose (FDG). In our longitudinal study, we investigated the tumour heterogeneity and the relationship between FDG and [68Ga]Ga-NODAGA-c(RGDfK)2 (RGD) accumulation in breast cancer xenografts.

MATERIALS AND METHODS

Two groups of cell lines, a fast-growing (4T1) and a slow-growing cell line (MDA-MB-HER2+), were inoculated into SCID mice. RGD and FDG scans were performed in all mice on separate days at four time points. Assessment of tumour uptake based on positron emission tomography/magnetic resonance imaging images was performed using tumour/muscle ratios with the Muscle-Spacing Correction Method to minimize the partial volume effect of the urinary bladder.

RESULTS

In the 4T1 group, both radiopharmaceuticals visualized the highly heterogeneous structure of the tumours and showed correlations with tumour growth. Relative linear correlations between FDG and RGD tumour/muscle ratios were observed in all tumours, evident in both high and low-activity areas of 4T1 tumours. When comparing the two groups of different cell lines, SUV ratios in the 4T1 group were higher, especially with [18F]F-FDG. Our findings highlight the correlations between FDG and RGD, particularly in aggressive breast cancer.

CONCLUSION

This preliminary study supports the combined use of FDG and RGD PET imaging to better characterize tumor heterogeneity and aggressiveness in breast cancer. The observed correlation between FDG and RGD uptake offers insights into the metabolic and vascular behavior of different cancer subtypes, highlighting distinct patterns in 4T1 and MDA-MB-HER2+ lines. This dual-tracer approach shows promise for tailoring therapies based on tumor subtype, though further studies with larger samples are needed to validate these initial findings.

Garlic peel extract as an antioxidant inhibits triple-negative breast tumor growth and angiogenesis by inhibiting cyclooxygenase-2 expression

Garlic peels are frequently disposed of as agro-waste; their bioactivity and physiological activity for health benefits and disease protection are neglected. This study aims to examine the potential inhibitory effects of garlic peel extract as an antioxidant on 4 T1 triple-negative breast cancer (TNBC) tumors in mice. The bioactive constituents of garlic peel were identified through HPLC-MS/MS analysis, while the antioxidant properties of garlic peel extract were assessed using peroxyl radical scavenging capacity (PSC) and cellular antioxidant activity (CAA) assays. Subsequently, the inhibitory effects of garlic peel extract on 4T1 tumor growth were evaluated using a 4T1 model. The results showed that 433 polyphenol compounds were found in garlic peel extract; among them, flavonoids and phenolic acid are the primary polyphenols with natural antioxidant activity, and both high and low concentrations of the extract exhibited tumor-suppressive effects. Immunohistochemistry was employed to assess the expression levels of COX-2, CD31, VEGFA, MMP2, and MMP9 in tumor tissues in order to investigate the antioxidant properties of garlic peel extract, specifically its ability to suppress COX-2 expression. The findings of this study offer a foundation for the advancement of garlic peel-based functional products and contribute to the identification of potential anti-cancer agents and therapeutic targets.

Identification of a Prognostic Gene Signature Based on Lipid Metabolism-Related Genes in Esophageal Squamous Cell Carcinoma

Background

Dysregulation of lipid metabolism is common in cancer. However, the molecular mechanism underlying lipid metabolism in esophageal squamous cell carcinoma (ESCC) and its effect on patient prognosis are not well understood. The objective of our study was to construct a lipid metabolism-related prognostic model to improve prognosis prediction in ESCC.

Methods

We downloaded the mRNA expression profiles and corresponding survival data of patients with ESCC from the Gene Expression Omnibus (GEO) and The Cancer Genome Atlas (TCGA) databases. We performed differential expression analysis to identify differentially expressed lipid metabolism-related genes (DELMGs). We used Univariate Cox regression and least absolute shrinkage and selection operator (LASSO) analyses to establish a risk model in the GEO cohort and used data of patients with ESCC from the TCGA cohort for validation. We also explored the relationship between the risk model and the immune microenvironment via infiltrated immune cells and immune checkpoints.

Results

The result showed that 132 unique DELMGs distinguished patients with ESCC from the controls. We identified four genes (ACAA1, ACOT11, B4GALNT1, and DDHD1) as prognostic gene expression signatures to construct a risk model. Patients were classified into high- and low-risk groups as per the signature-based risk score. We used the receiver operating characteristic (ROC) curve and the Kaplan-Meier (KM) survival analysis to validate the predictive performance of the 4-gene signature in both the training and validation sets. Infiltrated immune cells and immune checkpoints indicated a difference in the immune status between the two risk groups.

Conclusion

The results of our study indicated that a prognostic model based on the 4-gene signature related to lipid metabolism was useful for the prediction of prognosis in patients with ESCC.

Isocitrate dehydrogenase 1 mutation drives leukemogenesis by PDGFRA activation due to insulator disruption in acute myeloid leukemia (AML)

Acute myeloid leukemia (AML) is characterized by complex molecular alterations and driver mutations. Elderly patients show increased frequencies of IDH mutations with high chemoresistance and relapse rates despite recent therapeutic advances. Besides being associated with global promoter hypermethylation, IDH1 mutation facilitated changes in 3D DNA-conformation by CTCF-anchor methylation and upregulated oncogene expression in glioma, correlating with poor prognosis. Here, we investigated the role of IDH1 p.R132H mutation in altering 3D DNA-architecture and subsequent oncogene activation in AML. Using public RNA-Seq data, we identified upregulation of tyrosine kinase PDGFRA in IDH1-mutant patients, correlating with poor prognosis. DNA methylation analysis identified CpG hypermethylation within a CTCF-anchor upstream of PDGFRA in IDH1-mutant patients. Increased PDGFRA expression, PDGFRA-CTCF methylation and decreased CTCF binding were confirmed in AML CRISPR cells with heterozygous IDH1 p.R132H mutation and upon exogenous 2-HG treatment. IDH1-mutant cells showed higher sensitivity to tyrosine kinase inhibitor dasatinib, which was supported by reduced blast count in a patient with refractory IDH1-mutant AML after dasatinib treatment. Our data illustrate that IDH1 p.R132H mutation leads to CTCF hypermethylation, disrupting DNA-looping and insulation of PDGFRA, resulting in PDGFRA upregulation in IDH1-mutant AML. Treatment with dasatinib may offer a novel treatment strategy for IDH1-mutant AML.

Solid-state emitting twisted π-conjugate as AIE-active DSE-gen: in vitro anticancer properties against FaDu and 4T1 with biocompatibility and bioimaging

Dual-state emissive fluorogens (DSE-gens) are currently defining their importance as a transpiring tool in biological and biomedical applications. This work focuses on designing and synthesizing indole-anthracene-based solid-state emitting twisted π-conjugates using a metal-free protocol to achieve AIE-active DSE-gens, expanding their scope in biological applications. Special effort has been made to introduce proficient and photo/thermostable DSE-gens that inhibit cancer but not normal cells. Here, the lead DSE-gen initially detects cancer and normal cells by bioimaging; however, it could also confirm and distinguish cancer cells from normal cells by its abated fluorescence signal after killing cancer cells. In contrast, the fluorescence signals for a normal cell remain unscathed. Surprisingly, these molecules displayed decent anticancer properties against FaDu and 4T1 but not MCF-7 cell lines. From a series of newly designed indole-based molecules, we report one single 2,3,4-trimethoxybenzene-linked DSE-gen (the lead), exhibiting high ROS generation, less haemolysis, and less cytotoxicity than doxorubicin (DOX) for normal cells, crucial parameters for a biocompatible in vitro anticancer probe. Thus, we present a potentially applicable anticancer drug, offering a bioactive material with bioimaging efficacy and a way to detect dead cancer cells selectively. The primary mechanism behind the identified outcomes is deciphered with the support of experimental (steady-state and time-resolved fluorescence, biological assays, cellular uptake) and molecular docking studies.

Phenanthroindolizidine Alkaloids Isolated from Tylophora ovata as Potent Inhibitors of Inflammation, Spheroid Growth, and Invasion of Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC), representing the most aggressive form of breast cancer with currently no targeted therapy available, is characterized by an inflammatory and hypoxic tumor microenvironment. To date, a broad spectrum of anti-tumor activities has been reported for phenanthroindolizidine alkaloids (PAs), however, their mode of action in TNBC remains elusive. Thus, we investigated six naturally occurring PAs extracted from the plant Tylophora ovata: O-methyltylophorinidine (1) and its five derivatives tylophorinidine (2), tylophoridicine E (3), 2-demethoxytylophorine (4), tylophoridicine D (5), and anhydrodehydrotylophorinidine (6). In comparison to natural (1) and for more-in depth studies, we also utilized a sample of synthetic O-methyltylophorinidine (1s). Our results indicate a remarkably effective blockade of nuclear factor kappa B (NFκB) within 2 h for compounds (1) and (1s) (IC50 = 17.1 ± 2.0 nM and 3.3 ± 0.2 nM) that is different from its effect on cell viability within 24 h (IC50 = 13.6 ± 0.4 nM and 4.2 ± 1 nM). Furthermore, NFκB inhibition data for the additional five analogues indicate a structure–activity relationship (SAR). Mechanistically, NFκB is significantly blocked through the stabilization of its inhibitor protein kappa B alpha (IκBα) under normoxic as well as hypoxic conditions. To better mimic the TNBC microenvironment in vitro, we established a 3D co-culture by combining the human TNBC cell line MDA-MB-231 with primary murine cancer-associated fibroblasts (CAF) and type I collagen. Compound (1) demonstrates superiority against the therapeutic gold standard paclitaxel by diminishing spheroid growth by 40% at 100 nM. The anti-proliferative effect of (1s) is distinct from paclitaxel in that it arrests the cell cycle at the G0/G1 state, thereby mediating a time-dependent delay in cell cycle progression. Furthermore, (1s) inhibited invasion of TNBC monoculture spheroids into a matrigel®-based environment at 10 nM. In conclusion, PAs serve as promising agents with presumably multiple target sites to combat inflammatory and hypoxia-driven cancer, such as TNBC, with a different mode of action than the currently applied chemotherapeutic drugs.

Relationship between the oxidative status and the tumor growth in transplanted triple-negative 4T1 breast tumor mice after oral administration of rhenium(I)-diselenoether

BACKGROUND

Selective inhibitory effects of rhenium(I)-diselenoether (Re-diSe) were observed in cultured breast malignant cells. They were attributed to a decrease in Reactive Oxygen Species (ROS) production. A concomitant decrease in the production of Transforming Growth Factor-beta (TGFβ1), Insulin Growth Factor 1 (IGF1), and Vascular Endothelial Growth Factor A (VEGFA) by the malignant cells was also observed.

AIM

The study aimed to investigate the anti-tumor effects of Re-diSe on mice bearing 4T1 breast tumors, an experimental model of triple-negative breast cancer, and correlate them with several biomarkers.

MATERIAL AND METHODS

4T1 mammary breast cancer cells were orthotopically inoculated into syngenic BALB/c Jack mice. Different doses of Re-diSe (1, 10, and 60 mg/kg) were administered orally for 23 consecutive days to assess the efficacy and toxicity. The oxidative status was evaluated by assaying Advanced Oxidative Protein Products (AOPP), and by the dinitrophenylhydrazone (DNPH) test in plasma of healthy mice, non-treated tumor-bearing mice (controls), treated tumor-bearing mice, and tumors in all tumor-bearing mice. Tumor necrosis factor (TNFα), VEGFA, VEGFB, TGFβ1, Interferon, and selenoprotein P (selenoP) were selected as biomarkers.

RESULTS

Doses of 1 and 10 mg/kg did not affect the tumor weights. There was a significant increase in the tumor weights in mice treated with the maximum dose of 60 mg/kg, concomitantly with a significant decrease in AOPP, TNFα, and TGFβ1 in the tumors. SelenoP concentrations increased in the plasma but not in the tumors.

CONCLUSION

We did not confirm the anti-tumor activity of the Re-diSe compound in this experiment. However, the transplantation of the tumor cells did not induce an expected pro-oxidative status without any increase of the oxidative biomarkers in the plasma of controls compared to healthy mice. This condition could be essential to evaluate the effect of an antioxidant drug. The choice of the experimental model will be primordial to assess the effects of the Re-diSe compound in further studies.

Discoidin Domain Receptor 2 Expression as Worse Prognostic Marker in Invasive Breast Cancer

Discoidin domain receptor 2 (DDR2) is arising as a promising therapeutic target in breast carcinoma (BC). The ability of DDR2 to bind to collagen promotes protumoral responses in cancer cells that influence the tumor microenvironment (TME). Nonetheless, the interrelation between DDR2 expression and TME modulation during BC progression remains poorly known. For this reason, we aim to evaluate the correlation between intratumoral expression of DDR2 and the infiltration of the main TME cell populations, cancer-associated fibroblasts (CAFs), and tumor-associated macrophages (TAMs). First, collagen and DDR2 expression levels were analyzed in human invasive BC samples. Then, DDR2 status correlation with tumor aggressiveness and patient survival were retrieved from different databases. Subsequently, the main pathways, cell types, and tissues correlated with DDR2 expression in BC were obtained through bioinformatics approach. Finally, we studied the association of DDR2 expression with the recruitment of CAFs and TAMs. Our findings showed that, together with the expected overexpression of TME markers, DDR2 was upregulated in tumor samples. Besides, we uncovered that altered TME markers were linked to DDR2 expression in invasive BC patients. Consequently, DDR2 modulates the stromal reaction through CAFs and TAMs infiltration and could be used as a potential worse prognostic factor in the treatment response of invasive BC.

Overcoming Therapy Resistance and Relapse in TNBC: Emerging Technologies to Target Breast Cancer-Associated Fibroblasts

Breast cancer is the most diagnosed cancer and is the leading cause of cancer mortality in women. Triple-negative breast cancer (TNBC) is an aggressive form of breast cancer. Often, TNBC is not effectively treated due to the lack of specificity of conventional therapies and results in relapse and metastasis. Breast cancer-associated fibroblasts (BCAFs) are the predominant cells that reside in the tumor microenvironment (TME) and regulate tumorigenesis, progression and metastasis, and therapy resistance. BCAFs secrete a wide range of factors, including growth factors, chemokines, and cytokines, some of which have been proved to lead to a poor prognosis and clinical outcomes. This TME component has been emerging as a promising target due to its crucial role in cancer progression and chemotherapy resistance. A number of therapeutic candidates are designed to effectively target BCAFs with a focus on their tumor-promoting properties and tumor immune response. This review explores various agents targeting BCAFs in TNBC, including small molecules, nucleic acid-based agents, antibodies, proteins, and finally, nanoparticles.

Cancer-Associated Fibroblasts in Breast Cancer Treatment Response and Metastasis

Breast cancer (BrCa) is the leading cause of death among women worldwide, with about one million new cases diagnosed each year. In spite of the improvements in diagnosis, early detection and treatment, there is still a high incidence of mortality and failure to respond to current therapies. With the use of several well-established biomarkers, such as hormone receptors and human epidermal growth factor receptor-2 (HER2), as well as genetic analysis, BrCa patients can be categorized into multiple subgroups: Luminal A, Luminal B, HER2-enriched, and Basal-like, with specific treatment strategies. Although chemotherapy and targeted therapies have greatly improved the survival of patients with BrCa, there is still a large number of patients who relapse or who fail to respond. The role of the tumor microenvironment in BrCa progression is becoming increasingly understood. Cancer-associated fibroblasts (CAFs) are the principal population of stromal cells in breast tumors. In this review, we discuss the current understanding of CAFs' role in altering the tumor response to therapeutic agents as well as in fostering metastasis in BrCa. In addition, we also review the available CAFs-directed molecular therapies and their potential implications for BrCa management.