Risk Signature of Cancer-Associated Fibroblast-Secreted Cytokines Associates With Clinical Outcomes of Breast Cancer

A Pioglitazone Nanoformulation Designed for Cancer-Associated Fibroblast Reprogramming and Cancer Treatment

The recent focus of cancer therapeutics research revolves around modulating the immunosuppressive tumor microenvironment (TME) to enhance efficacy. The tumor stroma, primarily composed of cancer-associated fibroblasts (CAFs), poses significant obstacles to therapeutic penetration, influencing resistance and tumor progression. Reprogramming CAFs into an inactivated state has emerged as a promising strategy, necessitating innovative approaches. This study pioneers the design of a nanoformulation using pioglitazone, a Food and Drug Administration-approved anti-diabetic drug, to reprogram CAFs in the breast cancer TME. Glutathione (GSH)-responsive dendritic mesoporous organosilica nanoparticles loaded with pioglitazone (DMON-P) are designed for the delivery of cargo to the GSH-rich cytosol of CAFs. DMON-P facilitates pioglitazone-mediated CAF reprogramming, enhancing the penetration of doxorubicin (Dox), a therapeutic drug. Treatment with DMON-P results in the downregulation of CAF biomarkers and inhibits tumor growth through the effective delivery of Dox. This innovative approach holds promise as an alternative strategy for enhancing therapeutic outcomes in CAF-abundant tumors, particularly in breast cancer.

Fibroblast heterogeneity and functions: insights from single-cell sequencing in wound healing, breast cancer, ovarian cancer and melanoma

Cancer has been described as the wound that does not heal, in large part due to fibroblast involvement. Activation of cancer-associated fibroblasts (CAFs) contributes to critical features of the tumor microenvironment, including upregulation of key marker proteins, recruitment of immune cells, and deposition of extracellular matrix (ECM)-similar to fibroblast activation in injury-induced wound healing. Prior to the widespread availability of single-cell RNA sequencing (scRNA seq), studies of CAFs or fibroblasts in wound healing largely relied on models guided by individual fibroblast markers, or methods with less resolution to unravel the heterogeneous nature of CAFs and wound healing fibroblasts (especially regarding scarring outcome). Here, insights from the enhanced resolution provided by scRNA sequencing of fibroblasts in normal wound healing, breast cancer, ovarian cancer, and melanoma are discussed. These data have revealed differences in expression of established canonical activation marker genes, epigenetic modifications, fibroblast lineages, new gene and proteins of clinical interest for further experimentation, and novel signaling interactions with other cell types that include spatial information.

The anti-neoplastic effects of metformin modulate the acquired phenotype of fibroblast cells in the breast cancer-normal fibroblast co-culture system

Intracellular communications between breast cancer and fibroblast cells were reported to be involved in cancer proliferation, growth, and therapy resistance. The hallmarks of cancer-fibroblast interactions, consisting of caveolin 1 (Cav1) and mono-carboxylate transporter 4 (MCT4) (metabolic coupling markers), along with IL-6, TGFβ, and lactate secretion, are considered robust biomarkers predicting recurrence and metastasis. In order to promote a novel phenotype in normal fibroblasts, we predicted that breast cancer cells could be able to cause loss of Cav1 and increase of MCT4, as well as elevate IL-6 and TGFβ in nearby normal fibroblasts. We created a co-culture model using breast cancer (4T1) and normal fibroblast (NIH3T3) cell lines cultured under specific experimental conditions in order to directly test our theory. Moreover, we show that long-term co-culture of breast cancer cells and normal fibroblasts promotes loss of Cav1 and gain of MCT4 in adjacent fibroblasts and increase lactate secretion. These results were validated using the monoculture of each group separately as a control. In this system, we show that metformin inhibits IL-6 and TGFβ secretion and re-expresses Cav1 in both cells. However, MCT4 and lactate stayed high after treatment with metformin. In conclusion, our work shows that co-culture with breast cancer cells may cause significant alterations in the phenotype and secretion of normal fibroblasts. Metformin, however, may change this state and affect fibroblasts' acquired phenotypes. Moreover, mitochondrial inhibition by metformin after 8 days of treatment, significantly hinders tumor growth in mouse model of breast cancer.

EDIL3 as an Angiogenic Target of Immune Exclusion Following Checkpoint Blockade

Immune checkpoint blockade (ICB) has become the standard of care for several solid tumors. Multiple combinatorial approaches have been studied to improve therapeutic efficacy. The combination of antiangiogenic agents and ICB has demonstrated efficacy in several cancers. To improve the mechanistic understanding of synergies with these treatment modalities, we performed screens of sera from long-term responding patients treated with ipilimumab and bevacizumab. We discovered a high-titer antibody response against EGF-like repeats and discoidin I-like domains protein 3 (EDIL3) that correlated with favorable clinical outcomes. EDIL3 is an extracellular protein, previously identified as a marker of poor prognosis in various malignancies. Our Tumor Immune Dysfunction and Exclusion analysis predicted that EDIL3 was associated with immune exclusion signatures for cytotoxic immune cell infiltration and nonresponse to ICB. Cancer-associated fibroblasts (CAF) were predicted as the source of EDIL3 in immune exclusion-related cells. Furthermore, The Cancer Genome Atlas Skin Cutaneous Melanoma (TCGA-SKCM) and CheckMate 064 data analyses correlated high levels of EDIL3 with increased pan-fibroblast TGFβ response, enrichment of angiogenic signatures, and induction of epithelial-to-mesenchymal transition. Our in vitro studies validated EDIL3 overexpression and TGFβ regulation in patient-derived CAFs. In pretreatment serum samples from patients, circulating levels of EDIL3 were associated with circulating levels of VEGF, and like VEGF, EDIL3 increased the angiogenic abilities of patient-derived tumor endothelial cells (TEC). Mechanistically, three-dimensional microfluidic cultures and two-dimensional transmigration assays with TEC endorsed EDIL3-mediated disruption of the lymphocyte function-associated antigen-1 (LFA-1)-ICAM-1 interaction as a possible means of T-cell exclusion. We propose EDIL3 as a potential target for improving the transendothelial migration of immune cells and efficacy of ICB therapy.

The role of cancer-associated fibroblasts in breast cancer metastasis

Breast cancer deaths are primarily caused by metastasis. There are several treatment options that can be used to treat breast cancer. There are, however, a limited number of treatments that can either prevent or inhibit the spread of breast tumor metastases. Thus, novel therapeutic strategies are needed. Studies have increasingly focused on the importance of the tumor microenvironment (TME) in metastasis of breast cancer. As the most abundant cells in the TME, cancer-associated fibroblasts (CAFs) play important roles in cancer pathogenesis. They can remodel the structure of the extracellular matrix (ECM) and engage in crosstalk with cancer cells or other stroma cells by secreting growth factors, cytokines, and chemokines, as well as components of the ECM, which assist the tumor cells to invade through the TME and cause distant metastasis. Clinically, CAFs not only foster the initiation, growth, angiogenesis, invasion, and metastasis of breast cancer but also serve as biomarkers for diagnosis, therapy, and prediction of prognosis. In this review, we summarize the biological characteristics and subtypes of CAFs and their functions in breast cancer metastasis, focusing on their important roles in the diagnosis, prognosis, and treatment of breast cancer. Recent studies suggest that CAFs are vital partners of breast cancer cells that assist metastasis and may represent ideal targets for prevention and treatment of breast cancer metastasis.

Cancer-Associated Fibroblast Risk Model for Prediction of Colorectal Carcinoma Prognosis and Therapeutic Responses

Colorectal carcinoma (CRC) is a malignant tumor of the digestive system. Cancer-associated fibroblasts (CAFs) are important cellular elements in the tumor microenvironment of CRC, which contribute to CRC progression and immune escape. To predict the survival outcome and therapeutic responses of CRC patients, we identified genes connected with stromal CAF and generated a risk model. In this study, we used multiple algorithms to reveal CAF-related genes in the Gene Expression Omnibus and The Cancer Genome Atlas datasets and construct a risk model composed by prognostic CAF-associated genes. Then, we evaluated whether the risk score could predict CAF infiltrations and immunotherapy in CRC and confirmed the expression of the risk model in CAFs. Our results showed that CRC patients with high CAF infiltrations and stromal score had worse prognosis than those with low-CAF infiltrations and stromal score. We obtained 88 stromal CAF-associated hub-genes and generated a CAF risk model consisting of ZNF532 and COLEC12. Compared with low-risk group, the overall survival in high-risk group was shorter. The relationship between risk score, ZNF532 and COLEC12, and stromal CAF infiltrations and CAF markers was positive. In addition, the effect of immunotherapy in the high-risk group was not as good as that in the low-risk group. Patients with the high-risk group were enriched in chemokine signaling pathway, cytokine-cytokine receptor interaction, and focal adhesion. Finally, we confirmed that the expressions of ZNF532 and COLEC12 in risk model were widely distributed in fibroblasts of CRC, and the expression levels were higher in fibroblasts than CRC cells. In conclusion, the prognostic CAF signature of ZNF532 and COLEC12 can be applied not only to predict the prognosis of CRC patients but also to evaluate the immunotherapy response in CRC patients, and these findings provide the possibility for further development of individualized treatment for CRC.

Development and validation of a cancer-associated fibroblast-derived lncRNA signature for predicting clinical outcomes in colorectal cancer

Cancer-associated fibroblasts (CAFs) are actively involved in cancer progression through generating extracellular matrix and orchestrating the crosstalk within the tumor microenvironment (TME). This study aimed to develop and validate a CAF-derived lncRNA (long non-coding RNA) (CAFDL) signature for predicting clinical outcomes in colorectal cancer (CRC). Clinical data and transcriptomic profiles of 2,320 patients with CRC from The Cancer Genome Atlas (TCGA)-COAD and TCGA-READ datasets and 16 Gene Expression Omnibus datasets were included in this study. CAFDLs were identified using weighted gene co-expression network analysis. The CAFDL signature was constructed using the least absolute shrinkage and selection operator analysis in the TCGA-CRC training set. Multiple CRC cohorts and pan-cancer cohorts were used to validated the CAFDL signature. Patients with high CAFDL scores had significantly worse overall survival and disease-free survival than patients with low CAFDL scores in all CRC cohorts. In addition, non-responders to fluorouracil, leucovorin, and oxaliplatin (FOLFOX)/fluorouracil, leucovorin, and irinotecan (FOLFIRI) chemotherapy, chemoradiotherapy, bevacizumab, and immune checkpoint inhibitors had significantly higher CAFDL scores compared with responders. Pan-cancer analysis showed that CAFDL had prognostic predictive power in multiple cancers such as lung adenocarcinoma, breast invasive carcinoma, stomach adenocarcinoma, and thyroid carcinoma. The CAFDL signature was positively correlated with transforming growth factor-beta (TGF-β) signaling, epithelial–mesenchymal transition, and angiogenesis pathways but negatively correlated with the expression of immune checkpoints such as PDCD1, CD274, and CTLA4. The CAFDL signature reflects CAF properties from a lncRNA perspective and effectively predicts clinical outcomes in CRC and across pan-cancer. The CAFDL signature can serve as a useful tool for risk stratification and provide new insights into the underlying mechanisms of CAFs in cancer immunity.

Antibody-drug conjugates: beyond current approvals and potential future strategies

The recent approvals for antibody-drug conjugates (ADCs) in multiple malignancies in recent years have fuelled the ongoing development of this class of drugs. These novel agents combine the benefits of high specific targeting of oncogenic cell surface antigens with the additional cell kill from high potency cytotoxic payloads, thus achieving wider therapeutic windows. This review will summarise the clinical activity of ADCs in tumour types not covered elsewhere in this issue, such as gastrointestinal (GI) and genitourinary (GU) cancers and glioblastoma (GBM). In addition to the ongoing clinical testing of existing ADCs, there is substantial preclinical and early phase testing of newer ADCs or ADC incorporating strategies. This review will provide selected insights into such future development, focusing on the development of novel ADCs against new antigen targets in the tumour microenvironment (TME) and combination of ADCs with immuno-oncology (IO) agents.

Few, but Efficient: The Role of Mast Cells in Breast Cancer and Other Solid Tumors

Tumor outcome is determined not only by cancer cell-intrinsic features but also by the interaction between cancer cells and their microenvironment. There is great interest in tumor-infiltrating immune cells, yet mast cells have been less studied. Recent work has highlighted the impact of mast cells on the features and aggressiveness of cancer cells, but the eventual effect of mast cell infiltration is still controversial. Here, we review multifaceted findings regarding the role of mast cells in cancer, with a particular focus on breast cancer, which is further complicated because of its classification into subtypes characterized by different biological features, outcome, and therapeutic strategies.