TGF-β at the crossroads of multiple prognosis in breast cancer, and beyond

Overexpression of microRNA-611 inhibits TGF-β-induced epithelial-mesenchymal transition and migration in lung cancer cells through MAPKAP1

Metastasis is a major cause of death in patients with lung cancer (LC). microRNA-611 (miR-611), a miRNA, has been little studied in cancer. Here, we aimed to further elucidate the roles of miR-611 in epithelial-mesenchymal transition (EMT) and migration induced by transforming growth factor-β (TGF-β) in LC cells and the possible underlying mechanisms. miR-611 and MAPKAP1 expression was first identified in LC tissues from metastatic and nonmetastatic patients, and their expression was associated with overall survival. Gain- and loss-of-function experiments were performed to verify the impacts of miR-611 and MAPKAP1 on pAKT expression, EMT, and migration in LC cells treated with TGF-β. The interaction between miR-611 and MAPKAP1 was also determined with a luciferase reporter assay. In our study, miR-611 was expressed at low levels, and MAPKAP1 was highly expressed in LC tissues, which was associated with metastasis and short overall survival. Functionally, miR-611 inhibition or MAPKAP1 overexpression accelerated EMT and migration and upregulated pAKT in TGF-β-treated A549 and H1299 cells; miR-611 overexpression or MAPKAP1 silencing exerted the opposite effects as miR-611 inhibition or MAPKAP1 overexpression. Mechanistically, miR-611 could target and downregulate MAPKAP1. MAPKAP1 expression was also negatively correlated with miR-611 expression in LC tissues. In addition, miR-611 overexpression reduced the EMT and migration of TGF-β-treated A549 and H1299 cells by targeting MAPKAP1. In conclusion, miR-611 overexpression attenuated EMT and migration by targeting MAPKAP1 in TGF-β-induced LC cells, indicating that miR-611 is a biological target for LC treatment.

Interactions between hedgehog signaling pathway and the complex tumor microenvironment in breast cancer: current knowledge and therapeutic promises

Breast cancer ranks as one of the most common malignancies among women, with its prognosis and therapeutic efficacy heavily influenced by factors associated with the tumor cell biology, particularly the tumor microenvironment (TME). The diverse elements of the TME are engaged in dynamic bidirectional signaling interactions with various pathways, which together dictate the growth, invasiveness, and metastatic potential of breast cancer. The Hedgehog (Hh) signaling pathway, first identified in Drosophila, has been established as playing a critical role in human development and disease. Notably, the dysregulation of the Hh pathway is recognized as a major driver in the initiation, progression, and metastasis of breast cancer. Consequently, elucidating the mechanisms by which the Hh pathway interacts with the distinct components of the breast cancer TME is essential for comprehensively evaluating the link between Hh pathway activation and breast cancer risk. This understanding is also imperative for devising novel targeted therapeutic strategies and preventive measures against breast cancer. In this review, we delineate the current understanding of the impact of Hh pathway perturbations on the breast cancer TME, including the intricate and complex network of intersecting signaling cascades. Additionally, we focus on the therapeutic promise and clinical challenges of Hh pathway inhibitors that target the TME, providing insights into their potential clinical utility and the obstacles that must be overcome to harness their full therapeutic potential.

TGF-β signaling: critical nexus of fibrogenesis and cancer

The transforming growth factor-beta (TGF-β) signaling pathway is a vital regulator of cell proliferation, differentiation, apoptosis, and extracellular matrix production. It functions through canonical SMAD-mediated processes and noncanonical pathways involving MAPK cascades, PI3K/AKT, Rho-like GTPases, and NF-κB signaling. This intricate signaling system is finely tuned by interactions between canonical and noncanonical pathways and plays key roles in both physiologic and pathologic conditions including tissue homeostasis, fibrosis, and cancer progression. TGF-β signaling is known to have paradoxical actions. Under normal physiologic conditions, TGF-β signaling promotes cell quiescence and apoptosis, acting as a tumor suppressor. In contrast, in pathological states such as inflammation and cancer, it triggers processes that facilitate cancer progression and tissue remodeling, thus promoting tumor development and fibrosis. Here, we detail the role that TGF-β plays in cancer and fibrosis and highlight the potential for future theranostics targeting this pathway.

Spatiotemporally controlled Pseudomonas exotoxin transgene system combined with multifunctional nanoparticles for breast cancer antimetastatic therapy

The tumor microenvironment is a barrier to breast cancer therapy. Cancer-associated fibroblast cells (CAFs) can support tumor proliferation, metastasis, and drug resistance by secreting various cytokines and growth factors. Abnormal angiogenesis provides sufficient nutrients for tumor proliferation. Considering that CAFs express the sigma receptor (which recognizes anisamide, AA), we developed a CAFs and breast cancer cells dual-targeting nano drug delivery system to transport the LightOn gene express system, a spatiotemporal controlled gene expression consisting of a light-sensitive transcription factor and a specific minimal promoter. We adopted RGD (Arg-Gly-Asp) to selectively bind to the αvβ3 integrin on activated vascular endothelial cells and tumor cells. After the LightOn system has reached the tumor site, LightOn gene express system can spatiotemporal controllably express toxic Pseudomonas exotoxin An under blue light irradiation. The LightOn gene express system, combined with multifunctional nanoparticles, achieved high targeting delivery efficiency both in vitro and in vivo. It also displayed strong tumor and CAFs inhibition, anti-angiogenesis ability and anti-metastasis ability, with good safety. Moreover, it improved survival rate, survival time, and lung metastasis rate in a mouse breast cancer model. This study proves the efficacy of combining the LightOn system with targeted multifunctional nanoparticles in tumor and anti-metastatic therapy and provides new insights into tumor microenvironment regulation.

Construction of stemness gene score by bulk and single-cell transcriptome to characterize the prognosis of breast cancer

Breast cancer (BC) is a heterogeneous disease characterized by significant differences in prognosis and therapy response. Numerous prognostic tools have been developed for breast cancer. Usually these tools are based on bulk RNA-sequencing (RNA-Seq) and ignore tumor heterogeneity. Consequently, the goal of this study was to construct a single-cell level tool for predicting the prognosis of BC patients. In this study, we constructed a stemness-risk gene score (SGS) model based on single-sample gene set enrichment analysis (ssGSEA). Patients were divided into two groups based on the median SGS. Patients with a high SGS scores had a significantly worse prognosis than those with a low SGS, and these groups exhibited differences in several tumor characteristics, such as immune infiltration, gene mutations, and copy number variants. Our results indicate that the SGS is a reliable tool for predicting prognosis and response to immunotherapy in BC patients.