Therapeutic Implications of TGFβ in Cancer Treatment: A Systematic Review

Decoding tumor microenvironment: EMT modulation in breast cancer metastasis and therapeutic resistance, and implications of novel immune checkpoint blockers

Tumor microenvironment (TME) and epithelial-mesenchymal transition (EMT) play crucial roles in the initiation and progression of tumors. TME is composed of various cell types, such as immune cells, fibroblasts, and endothelial cells, as well as non-cellular components like extracellular matrix (ECM) proteins and soluble factors. These elements interact with tumor cells through a complex network of signaling pathways involving cytokines, growth factors, metabolites, and non-coding RNA-carrying exosomes. Hypoxic conditions within the TME further modulate these interactions, collectively influencing tumor growth, metastatic potential, and response to therapy. EMT represents a dynamic and reversible process where epithelial cells undergo phenotypic changes to adopt mesenchymal characteristics in several cancers, including breast cancers. This transformation enhances cell motility and imparts stem cell-like properties, which are closely associated with increased metastatic capability and resistance to conventional cancer treatments. Thus, understanding the crosstalk between the TME and EMT is essential for unraveling the underlying mechanisms of breast cancer metastasis and therapeutic resistance. This review uniquely examines the intricate interplay between the tumor TME and epithelial-mesenchymal transition EMT in driving breast cancer metastasis and treatment resistance. It explores the therapeutic potential of targeting the TME-EMT axis, specifically through CD73-TGF-β dual-blockade, to improve outcomes in triple-negative breast cancer. Additionally, it underscores new strategies to enhance immune checkpoint blockade (ICB) responses by modulating EMT, thereby offering innovative insights for more effective cancer treatment.

Transcriptional responses to direct and indirect TGFB1 stimulation in cancerous and noncancerous mammary epithelial cells

BACKGROUND

Transforming growth factor beta (TGFβ) is important for the morphogenesis and secretory function of the mammary gland. It is one of the main activators of the epithelial-mesenchymal transition (EMT), a process important for tissue remodeling and regeneration. It also provides cells with the plasticity to form metastases during tumor progression. Noncancerous and cancer cells respond differently to TGFβ. However, knowledge of the cellular signaling cascades triggered by TGFβ in various cell types is still limited.

METHODS

MCF10A (noncancerous, originating from fibrotic breast tissue) and MCF7 (cancer, estrogen receptor-positive) breast epithelial cells were treated with TGFB1 directly or through conditioned media from stimulated cells. Transcriptional changes (via RNA-seq) were assessed in untreated cells and after 1-6 days of treatment. Differentially expressed genes were detected with DESeq2 and the hallmark collection was selected for gene set enrichment analysis.

RESULTS

TGFB1 induces EMT in both the MCF10A and MCF7 cell lines but via slightly different mechanisms (signaling through SMAD3 is more active in MCF7 cells). Many EMT-related genes are expressed in MCF10A cells at baseline. Both cell lines respond to TGFB1 by decreasing the expression of genes involved in cell proliferation: through the repression of MYC (and the protein targets) in MCF10A cells and the activation of p63-dependent signaling in MCF7 cells (CDKN1A and CDKN2B, which are responsible for the inhibition of cyclin-dependent kinases, are upregulated). In addition, estrogen receptor signaling is inhibited and caspase-dependent cell death is induced only in MCF7 cells. Direct incubation with TGFB1 and treatment of cells with conditioned media similarly affected transcriptional profiles. However, TGFB1-induced protein secretion is more pronounced in MCF10A cells; therefore, the signaling is propagated through conditioned media (bystander effect) more effectively in MCF10A cells than in MCF7 cells.

CONCLUSIONS

Estrogen receptor-positive breast cancer patients may benefit from high levels of TGFB1 expression due to the repression of estrogen receptor signaling, inhibition of proliferation, and induction of apoptosis in cancer cells. However, some TGFB1-stimulated cells may undergo EMT, which increases the risk of metastasis.

Targeting TGFβ with chimeric switch receptor and secreted trap to improve T cells anti-tumor activity

Introduction

TGFβ is a major immunoinhibitory factor present in the microenvironment of solid tumors. Various cancer types acquire the ability to overexpress TGFβ to escape immune response. Specifically, TGFβ dampens cytotoxic T cell activity, and its presence has been correlated with tumor invasion and poor prognosis.

Methods

In this study, we developed two approaches to counteract the effects of TGFβ and provide a functional advantage to genetically engineered T cells in the immunoinhibitory tumor milieu. We designed a TGFβRI-based co-stimulatory switch receptor (CSRI), comprising the TGFβ receptor I extracellular binding domain and a 4-1BB co-stimulatory signaling moiety. Additionally, we tested the efficacy of a TGFβ-binding scFv trap produced by T cells.

Results

We demonstrated that both approaches enhanced tumor-specific T cell cytokine secretion, upregulated activation markers, and reduced inhibition markers upon co-culture with melanoma targets. Furthermore, CSRI and the anti-TGFβ trap exhibited improved anti-tumor function in vivo.

Conclusion

Overall, we show that targeting the TGFβ pathway can enhance cellular immunotherapy.

Targeting TGFβ receptor-mediated snail and twist: WSG, a polysaccharide from Ganoderma lucidum, and it-based dissolvable microneedle patch suppress melanoma cells

Cutaneous melanoma is a lethal skin cancer variant with pronounced aggressiveness and metastatic potential. However, few targeted medications inhibit the progression of melanoma. Ganoderma lucidum, which is a type of mushroom, is widely used as a non-toxic alternative adjunct therapy for cancer patients. This study determines the effect of WSG, which is a water-soluble glucan that is derived from G. lucidum, on melanoma cells. The results show that WSG inhibits cell viability and the mobility of melanoma cells. WSG induces changes in the expression of epithelial-to-mesenchymal transition (EMT)-related markers. WSG also downregulates EMT-related transcription factors, Snail and Twist. Signal transduction assays show that WSG reduces the protein levels in transforming growth factor β receptors (TGFβRs) and consequently inhibits the phosphorylation of intracellular signaling molecules, such as FAK, ERK1/2 and Smad2. An In vivo study shows that WSG suppresses melanoma growth in B16F10-bearing mice. To enhance transdermal drug delivery and prevent oxidation, two highly biocompatible compounds, polyvinyl alcohol (PVA) and polyvinylpyrrolidone (PVP), are used to synthesize a dissolvable microneedle patch that is loaded with WSG (MN-WSG). A functional assay shows that MN-WSG has an effect that is comparable to that of WSG alone. These results show that WSG has significant potential as a therapeutic agent for melanoma treatment. MN-WSG may allow groundbreaking therapeutic approaches and offers a novel method for delivering this potent compound effectively.

Combining cashew gum with cyclophosphamide in murine melanoma model: A strategy for the reduction of side effects

The understanding of cancer immunity and antitumor factors generated by natural polysaccharides is not yet fully comprehended. Polysaccharides, like cashew gum (CG), can exhibit immunomodulatory action and may assist in the antitumor process and side effects relieve. This study aimed to determine the antitumor effect of CG alone or in combination with cyclophosphamide (CTX), and its interactions with immune cells, in a murine melanoma model, using the B16-F10 cell line. Tumor growth inhibition, hematological, histopathological, ELISA, flow cytometry, immunofluorescence, and qRT-PCR analyses were performed to elucidate the antitumor potential, involvement of immune cells, and potential toxic effects. CG showed significant tumor growth inhibition, reaching up to 42.9 % alone and 51.4 % in combination with CTX, with mild toxicity to organs. CG enhanced leukocyte count, even in the presence of CTX. Furthermore, CG influenced the activation of tumor-associated macrophages (TAM), characterized by an increase in Il4, as well as a reduction in Ifng, Il1b, Tgfb, and Il6 gene expression. Nevertheless, these effects did not compromise the antitumor activity of CG. In summary, the combination of CG with CTX is a promising approach for leukopenia, one of the most important side effects of cancer treatment and deserves further investigation.

Aqueous Extract of Leaves and Flowers of Acmella caulirhiza Reduces the Proliferation of Cancer Cells by Underexpressing Some Genes and Activating Caspase-3

The increasing prevalence of cancers and the multiple side effects of cancer treatments have led researchers to constantly search for plants containing bioactive compounds with cell death properties. This work aimed at evaluating the antiproliferative effect of an Acmella caulirhiza extract. After evaluation of the in vitro antioxidant potential of the three extracts of Acmella caulirhiza (aqueous (AE-Ac), hydroethanolic (HEE-Ac), and ethanolic (EE-Ac)) through the scavenging of DPPH● and NO● radicals, the extract with the best antioxidant activity was selected for bioactive compound assessment and antiproliferative tests. Subsequently, the cytotoxic activity was evaluated on the viability of breast (MCF-7), brain (CT2A, SB-28, and GL-261), colon (MC-38), and skin (YUMM 1.7 and B16-F1) cancer lines using the MTT method. Then, the line where the extract was the most active was selected to evaluate the expression of certain genes involved in cancerogenesis by RT-PCR and the expression of cleaved caspase-3 involved in cell death mechanism by western blot. The AE-Ac showed the best scavenging activity with IC50s of 0.52 and 0.02 for DPPH● and NO●, respectively. This AE-Ac was found to contain alkaloids, flavonoids, and tannins and was more active on YUMM 1.7 cells (IC50 = 149.42 and 31.99 μg/mL for 24 and 48 h, respectively). Results also showed that AE-Ac downregulated the expression of inflammation (IL-1b (p = 0.017) and IL-6 (p = 0.028)), growth factors (PDGF (p = 0.039), IGF (p = 0.034), E2F1(p = 0.038), and E2F2(p = 0.016)), and antiapoptotic protein genes (Bcl-2 (p = 0.028) and Bcl-6 (p = 0.039)). The cleaved caspase-3 was positively modulated by the AE-Ac inducing thus cell death by apoptosis. AE-Ac showed inhibitory effects on the expression of genes involved in cancer progression making it a potential health intervention agent that can be exploited in cancer therapy protocols.

Epidermal growth factor potentiates EGFR(Y992/1173)-mediated therapeutic response of triple negative breast cancer cells to cold atmospheric plasma-activated medium

Cold atmospheric plasma (CAP) holds promise as a cancer-specific treatment that selectively kills various types of malignant cells. We used CAP-activated media (PAM) to utilize a range of the generated short- and long-lived reactive species. Specific antibodies, small molecule inhibitors and CRISPR/Cas9 gene-editing approaches showed an essential role for receptor tyrosine kinases, especially epidermal growth factor (EGF) receptor, in mediating triple negative breast cancer (TNBC) cell responses to PAM. EGF also dramatically enhanced the sensitivity and specificity of PAM against TNBC cells. Site-specific phospho-EGFR analysis, signal transduction inhibitors and reconstitution of EGFR-depleted cells with EGFR-mutants confirmed the role of phospho-tyrosines 992/1173 and phospholipase C gamma signaling in up-regulating levels of reactive oxygen species above the apoptotic threshold. EGF-triggered EGFR activation enhanced the sensitivity and selectivity of PAM effects on TNBC cells. The proposed approach based on the synergy of CAP and EGFR-targeted therapy may provide new opportunities to improve the clinical management of TNBC.

Copper chelation suppresses epithelial-mesenchymal transition by inhibition of canonical and non-canonical TGF-β signaling pathways in cancer

BACKGROUND

Metastatic cancer cells exploit Epithelial-mesenchymal-transition (EMT) to enhance their migration, invasion, and resistance to treatments. Recent studies highlight that elevated levels of copper are implicated in cancer progression and metastasis. Clinical trials using copper chelators are associated with improved patient survival; however, the molecular mechanisms by which copper depletion inhibits tumor progression and metastasis are poorly understood. This remains a major hurdle to the clinical translation of copper chelators. Here, we propose that copper chelation inhibits metastasis by reducing TGF-β levels and EMT signaling. Given that many drugs targeting TGF-β have failed in clinical trials, partly because of severe side effects arising in patients, we hypothesized that copper chelation therapy might be a less toxic alternative to target the TGF-β/EMT axis.

RESULTS

Our cytokine array and RNA-seq data suggested a link between copper homeostasis, TGF-β and EMT process. To validate this hypothesis, we performed single-cell imaging, protein assays, and in vivo studies. Here, we used the copper chelating agent TEPA to block copper trafficking. Our in vivo study showed a reduction of TGF-β levels and metastasis to the lung in the TNBC mouse model. Mechanistically, TEPA significantly downregulated canonical (TGF-β/SMAD2&3) and non-canonical (TGF-β/PI3K/AKT, TGF-β/RAS/RAF/MEK/ERK, and TGF-β/WNT/β-catenin) TGF-β signaling pathways. Additionally, EMT markers of MMP-9, MMP-14, Vimentin, β-catenin, ZEB1, and p-SMAD2 were downregulated, and EMT transcription factors of SNAI1, ZEB1, and p-SMAD2 accumulated in the cytoplasm after treatment.

CONCLUSIONS

Our study suggests that copper chelation therapy represents a potentially effective therapeutic approach for targeting TGF-β and inhibiting EMT in a diverse range of cancers.

Biochemical characterization and anti-cancer activity of tangential flow filtration system assisted purification of fucoglucan from Laminaria japonica

Polysaccharide from Laminaria japonica (LJPS) exhibits multiple biological functions. However, we found that crude LJPS doesn't show good anti-lung cancer activity in this study. We therefore used tangential flow filtration (TFF) system to optimize the anticancer activity of LJPS. We divided the crude LJPS into two fractions by TFF system with a 10 kDa filter and denoted as retentate (10K-R) and filtration (10K-F). The chemical assay revealed that the main molecular mass of 10K-R and 10K-F is about 985 and 3 kDa, respectively. The main components of 10K-R include fucose (19.3 %), and glucose (59.5 %); while glucose (88.6 %) is a major component of 10K-F. Biological functions showed that 10K-R but not 10K-F inhibited the viability and mobility of cancer cells. 10K-R downregulated expressions of transforming growth factor β receptor and Slug, and inhibited intracellular signaling molecules, including FAK, AKT, ERK1/2, and Smad2. This study is the first concept to purify the polysaccharide by TFF system and showed the potential mechanism of 10K-R inhibited cancer cells.

N-Rich, Polyphenolic Porous Organic Polymer and Its In Vitro Anticancer Activity on Colorectal Cancer

N-rich organic materials bearing polyphenolic moieties in their building networks and nanoscale porosities are very demanding in the context of designing efficient biomaterials or drug carriers for the cancer treatment. Here, we report the synthesis of a new triazine-based secondary-amine- and imine-linked polyphenolic porous organic polymer material TrzTFPPOP and explored its potential for in vitro anticancer activity on the human colorectal carcinoma (HCT 116) cell line. This functionalized (-OH, -NH-, -C=N-) organic material displayed an exceptionally high BET surface area of 2140 m2 g-1 along with hierarchical porosity (micropores and mesopores), and it induced apoptotic changes leading to high efficiency in colon cancer cell destruction via p53-regulated DNA damage pathway. The IC30, IC50, and IC70 values obtained from the MTT assay are 1.24, 3.25, and 5.25 μg/mL, respectively.

Hypoxia Selectively Increases a SMAD3 Signaling Axis to Promote Cancer Cell Invasion

Transforming growth factor β (TGFβ) plays a paradoxical role in cancer, first inhibiting then promoting its progression, a duality that poses a real challenge for the development of effective TGFβ-targeted therapies. The major TGFβ downstream effectors, SMAD2 and SMAD3, display both distinct and overlapping functions and accumulating evidence suggests that their activation ratio may contribute to the dual effect of TGFβ. However, the mechanisms responsible for their selective activation remain poorly understood. Here, we provide experimental evidence that hypoxia induces the pro-invasive arm of TGFβ signaling through a selective increase in SMAD3 interaction with SMAD-Anchor for Receptor Activation (SARA). This event relies on HDAC6-dependent SMAD3 bioavailability, as well as increased SARA recruitment to EEA1+ endosomes. A motility gene expression study indicated that SMAD3 selectively increased the expression of ITGB2 and VIM, two genes that were found to be implicated in hypoxia-induced cell invasion and associated with tumor progression and metastasis in cohorts of cancer patients. Furthermore, CAM xenograft assays show the significant benefit of selective inhibition of the SMAD3 signaling pathway as opposed to global TGFβ inhibition in preventing tumor progression. Overall, these results suggest that fine-tuning of the pro-invasive HDAC6-SARA-SMAD3 axis could be a better strategy towards effective cancer treatments.

Research progress on drugs targeting the TGF-β signaling pathway in fibrotic diseases

Tissue fibrosis is a key factor leading to disability and death worldwide; however, thus far, there are no approved treatments for fibrosis. Transforming growth factor (TGF)-β is a major pro-fibrotic cytokine, which is expected to become a target in the treatment of fibrosis; however, since TGF-β has a wide range of biological functions involving a variety of biological processes in the body, a slight change in TGF-β may have a systematic effect. Indiscriminate inhibition of TGF-β can lead to adverse reactions, which can affect the efficacy of treatment. Therefore, it has become very important to explore how both the TGF-β signaling pathway is inhibited and the safe and efficient TGF-β small molecule inhibitors or neutralizing antibodies are designed in the treatment of fibrotic diseases. In this review, we mainly discuss the key role of the TGF-β signaling pathway in fibrotic diseases, as well as the development of fibrotic drugs in recent years, and explore potential targets in the treatment of fibrotic diseases in order to guide subsequent drug development.