Relaxin-encapsulated polymeric metformin nanoparticles remodel tumor immune microenvironment by reducing CAFs for efficient triple-negative breast cancer immunotherapy

Current Status of Breast Cancer Immunotherapy and Prognosis-Related Markers

Breast cancer, being the most common type of cancer globally, stands out as the primary malignant tumor affecting females. With the advent of breast cancer immunotherapy, inhibitors targeting immune checkpoints such as anti-PD-1 (Programmed cell death protein 1) / PD-L1 (Programmed cell death-Ligand 1) and CTLA-4 (Cytotoxic T Lymphocyte-Associated Antigen-4) have demonstrated promising outcomes for breast cancer patients across all molecular subtypes, particularly those with advanced breast cancer and triple-negative breast cancer (TNBC). Our current focus lies in accurately predicting the prognosis of breast cancer patients and the effectiveness of immunotherapy. This article provides a review of emerging biomarkers for breast cancer, encompassing immune-related markers, metabolic indicators, and potential prognosis-related markers. The primary emphasis of the article is to review immune-related tumor biomarkers in breast cancer. Our goal is to summarize relevant studies capable of forecasting breast cancer prognosis and immunotherapy effectiveness. Lastly, we delve into the future directions of breast cancer immunotherapy development.

Epigenetic regulators combined with tumour immunotherapy: current status and perspectives

Immunotherapy, particularly immune checkpoint inhibitor therapy, has demonstrated clinical benefits in solid tumours. Despite its satisfactory clinical efficacy, it still faces several issues, such as limited eligibility, low response rates and cytotoxicity. Cancer epigenetics implies that tumour cells exhibit unique phenotypes because of their unique characteristics, thus reprogramming of the epigenome holds promise for cancer therapy. Epigenetic regulation plays an important role in regulating gene expression during tumour development and maintenance. Epigenetic regulators induce cancer cell cycle arrest, apoptosis and differentiation of cancer cells, thereby exerting anti-tumour effects. Recent studies have revealed a significant correlation between epigenetic regulatory factors and immune checkpoint therapy. Epigenetics can modulate various aspects of the tumour immune microenvironment and immune response to enhance the sensitivity of immunotherapy, such as lowering the concentration required and mitigating cytotoxicity. This review primarily discusses DNA methyltransferase inhibitors, histone deacetylase inhibitors, enhancer of zeste homolog 2 inhibitors and lysine-specific demethylase 1 inhibitors, which are associated with transcriptional repression. This repression alters the expression of genes involved in the immune checkpoint, thereby enhancing the effectiveness of immunotherapy. We also discuss the potential and challenges of tumour immunotherapy and highlight its advantages, application challenges and clinical research on integrating epigenetic regulatory factors with tumour immunotherapy.

Metformin sensitizes triple-negative breast cancer to histone deacetylase inhibitors by targeting FGFR4

BACKGROUND

Triple-negative breast cancer (TNBC) is characterized by high malignancy, strong invasiveness, and a propensity for distant metastasis, leading to poor prognosis and relatively limited treatment options. Metformin, as a first-line oral hypoglycemic agent, has garnered widespread research interest in recent years due to its potential in cancer prevention and treatment. However, its efficacy varies significantly across different tumor types. Histone deacetylase inhibitors (HDACi), such as SAHA, have demonstrated antitumor activity, but TNBC responds poorly to HDACi monotherapy, possibly due to feedback activation of the JAK-STAT pathway. Exploring the synergistic potential and underlying mechanisms of combining metformin with HDACi in TNBC treatment is crucial.

METHODS

We predicted the synergistic effects of metformin and SAHA in TNBC using multiple computational methods (CMap, DTsyn, and DrugComb). We also developed a cancer-specific compound mimic library (CDTSL) and applied a three-step strategy to identify genes fitting the "metformin sensitization" model. Subsequently, we evaluated the synergistic effects of metformin and SAHA in TNBC cell lines through cell proliferation, colony formation, and apoptosis assays. Furthermore, we investigated the molecular mechanisms of the combined treatment using techniques such as transcriptome sequencing, chromatin immunoprecipitation (ChIP), Western blotting, and measurement of extracellular acidification rate (ECAR). Additionally, we assessed the in vivo antitumor effects of the combined therapy in a nude mouse subcutaneous xenograft model.

RESULTS

CMap, DTsyn, and DrugComb all predicted the synergistic effects of SAHA and metformin in TNBC. The screening results revealed that HDAC10 played a key role in metformin sensitization. We found that the combination of metformin and SAHA exhibited synergistic antitumor effects (combination index CI < 0.9) in TNBC cell lines. Mechanistically, metformin inhibited histone acetylation on FGFR4, thereby blocking the feedback activation of FGFR4 downstream pathways induced by SAHA. Furthermore, metformin interfered with the glycolysis process induced by SAHA, altering the metabolic reprogramming of tumor cells. In in vivo experiments, the combined treatment of metformin and SAHA significantly inhibited the growth of subcutaneous tumors in nude mice.

CONCLUSIONS

Metformin enhances the sensitivity of TNBC to HDAC inhibitors by blocking the FGFR4 pathway and interfering with metabolic reprogramming. When used in combination with SAHA, metformin exhibits synergistic antitumor effects. Our study provides a theoretical basis for the combined application of HDAC inhibitors and metformin, potentially offering a new strategy for the treatment of TNBC.

Regulation of cancer-associated fibroblasts for enhanced cancer immunotherapy using advanced functional nanomedicines: an updated review

The tumor microenvironment (TME) is a complex and dynamic ecosystem that plays a critical role in cancer progression. It comprises various cell types, including immune cells, tumor cells, and stromal cells. Among these, cancer-associated fibroblasts (CAFs) represent a heterogeneous population with diverse origins, phenotypes, and functions. Activated CAFs secrete multiple factors that promote tumor growth, migration, angiogenesis, and contribute to chemoresistance. Additionally, CAFs secrete extracellular matrix (ECM) components, such as collagen, which form a physical barrier that hinders the penetration of chemotherapeutic and immunotherapeutic agents. This ECM also influences immune cell infiltration, impeding their ability to effectively target tumor cells. As a result, modulating the activity of CAFs has emerged as a promising strategy to enhance the efficacy of tumor immunotherapy. Nano-delivery systems, constructed from various nanomaterials with high targeting specificity and biocompatibility, offer a compelling approach to deliver therapeutic agents or immunomodulatory factors directly to CAFs. This modulation can alter CAF function, reduce their tumor-promoting effects, and thereby improve the outcomes of immunotherapy. This review provides an in-depth exploration of the origins, functions, and interactions of CAFs within the TME, particularly in the context of immune suppression. Furthermore, it discusses the potential applications of functional nanocarrifers in modulating CAFs and enhancing the effectiveness of tumor immunotherapy, highlighting the significant progress and potential of nanotechnology in this area.

Nanoparticles Modulating the Immune Microenvironment in Breast Cancer Treatment

Breast cancer remains a significant therapeutic challenge, with the immune microenvironment playing a crucial role in its progression and treatment response. This review investigates the potential of nanoparticles to modulate the immune microenvironment in breast cancer therapy. Initially, we discuss the composition and influence of the immune microenvironment on breast cancer, followed by current strategies targeting these components. We then provide strategies of nanoparticles for targeting immune cells such as macrophages, dendritic cells, and T-cells. The role of nanoparticles in enhancing immune checkpoint blockade (ICB) and their application in cancer vaccines is also examined. Additionally, we explore the synergistic effects of combining nanoparticles with conventional therapies. The review addresses the challenges in clinical translation, focusing on safety, biocompatibility, and toxicity. Finally, we outline future research directions and the potential advancements in nanoparticle-based immunotherapy, emphasizing their transformative impact on breast cancer treatment.

Drug Delivery System Targeting Cancer-Associated Fibroblast for Improving Immunotherapy

Cancer-associated fibroblasts (CAFs) are a heterogeneous population of non-malignant cells that play a crucial role in the tumor microenvironment, increasingly recognized as key contributors to cancer progression, metastasis, and treatment resistance. So, targeting CAFs has always been considered an important part of cancer immunotherapy. However, targeting CAFs to improve the efficacy of tumor therapy is currently a major challenge. Nanomaterials show their unique advantages in the whole process. At present, nanomaterials have achieved significant accomplishments in medical applications, particularly in the field of cancer-targeted therapy, showing enormous potential. It has been confirmed that nanomaterials can not only directly target CAFs, but also interact with the tumor microenvironment (TME) and immune cells to affect tumorigenesis. As for the cancer treatment, nanomaterials could enhance the therapeutic effect in many ways. Therefore, in this review, we first summarized the current understanding of the complex interactions between CAFs and TME, immune cells, and tumor cells. Next, we discussed common nanomaterials in modern medicine and their respective impacts on the TME, CAFs, and interactions with tumors. Finally, we focus on the application of nano drug delivery system targeting CAFs in cancer therapy.

Targeting breast tumor extracellular matrix and stroma utilizing nanoparticles

Breast cancer is a complicated malignancy and is known as the most common cancer in women. Considerable experiments have been devoted to explore the basic impacts of the tumor stroma, particularly the extracellular matrix (ECM) and stromal components, on tumor growth and resistance to treatment. ECM is made up of an intricate system of proteins, glycosaminoglycans, and proteoglycans, and maintains structural support and controls key signaling pathways involved in breast tumors. ECM can block different drugs such as chemotherapy and immunotherapy drugs from entering the tumor stroma. Furthermore, the stromal elements, such as cancer-associated fibroblasts (CAFs), immune cells, and blood vessels, have crucial impacts on tumor development and therapeutic resistance. Recently, promising outcomes have been achieved in using nanotechnology for delivering drugs to tumor stroma and crossing ECM in breast malignancies. Nanoparticles have various benefits for targeting the breast tumor stroma, such as improved permeability and retention, extended circulation time, and the ability to actively target the area. This review covers the latest developments in nanoparticle therapies that focus on breast tumor ECM and stroma. We will explore different approaches using nanoparticles to target the delivery of anticancer drugs like chemotherapy, small molecule drugs, various antitumor products, and other specific synthetic therapeutic agents to the breast tumor stroma. Furthermore, we will investigate the utilization of nanoparticles in altering the stromal elements, such as reprogramming CAFs and immune cells, and also remodeling ECM.

CRISPR/Cas9-mediated knockout strategies for enhancing immunotherapy in breast cancer

Breast cancer, a prevalent disease with significant mortality rates, often presents treatment challenges due to its complex genetic makeup. This review explores the potential of combining Clustered Regularly Interspaced Short Palindromic Repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) gene knockout strategies with immunotherapeutic approaches to enhance breast cancer treatment. The CRISPR/Cas9 system, renowned for its precision in inducing genetic alterations, can target and eliminate specific cancer cells, thereby minimizing off-target effects. Concurrently, immunotherapy, which leverages the immune system's power to combat cancer, has shown promise in treating breast cancer. By integrating these two strategies, we can potentially augment the effectiveness of immunotherapies by knocking out genes that enable cancer cells to evade the immune system. However, safety considerations, such as off-target effects and immune responses, necessitate careful evaluation. Current research endeavors aim to optimize these strategies and ascertain the most effective methods to stimulate the immune response. This review provides novel insights into the integration of CRISPR/Cas9-mediated knockout strategies and immunotherapy, a promising avenue that could revolutionize breast cancer treatment as our understanding of the immune system's interplay with cancer deepens.

Nanotechnology Applications in Breast Cancer Immunotherapy

Next-generation cancer treatments are expected not only to target cancer cells but also to simultaneously train immune cells to combat cancer while modulating the immune-suppressive environment of tumors and hosts to ensure a robust and lasting response. Achieving this requires carriers that can codeliver multiple therapeutics to the right cancer and/or immune cells while ensuring patient safety. Nanotechnology holds great potential for addressing these challenges. This article highlights the recent advances in nanoimmunotherapeutic development, with a focus on breast cancer. While immune checkpoint inhibitors (ICIs) have achieved remarkable success and lead to cures in some cancers, their response rate in breast cancer is low. The poor response rate in solid tumors is often associated with the low infiltration of anti-cancer T cells and an immunosuppressive tumor microenvironment (TME). To enhance anti-cancer T-cell responses, nanoparticles are employed to deliver ICIs, bispecific antibodies, cytokines, and agents that induce immunogenic cancer cell death (ICD). Additionally, nanoparticles are used to manipulate various components of the TME, such as immunosuppressive myeloid cells, macrophages, dendritic cells, and fibroblasts to improve T-cell activities. Finally, this article discusses the outlook, challenges, and future directions of nanoimmunotherapeutics.

Enhancing cancer immunotherapy: Nanotechnology-mediated immunotherapy overcoming immunosuppression

Immunotherapy is an important cancer treatment method that offers hope for curing cancer patients. While immunotherapy has achieved initial success, a major obstacle to its widespread adoption is the inability to benefit the majority of patients. The success or failure of immunotherapy is closely linked to the tumor's immune microenvironment. Recently, there has been significant attention on strategies to regulate the tumor immune microenvironment in order to stimulate anti-tumor immune responses in cancer immunotherapy. The distinctive physical properties and design flexibility of nanomedicines have been extensively utilized to target immune cells (including tumor-associated macrophages (TAMs), T cells, myeloid-derived suppressor cells (MDSCs), and tumor-associated fibroblasts (TAFs)), offering promising advancements in cancer immunotherapy. In this article, we have reviewed treatment strategies aimed at targeting various immune cells to regulate the tumor immune microenvironment. The focus is on cancer immunotherapy models that are based on nanomedicines, with the goal of inducing or enhancing anti-tumor immune responses to improve immunotherapy. It is worth noting that combining cancer immunotherapy with other treatments, such as chemotherapy, radiotherapy, and photodynamic therapy, can maximize the therapeutic effects. Finally, we have identified the challenges that nanotechnology-mediated immunotherapy needs to overcome in order to design more effective nanosystems.

Relaxin combined with transarterial chemoembolization achieved synergistic effects and inhibited liver cancer metastasis in a rabbit VX2 model

OBJECTIVE

To explore the effect and mechanism of relaxin (RLX) in the growth and metastasis of livercancer after combination treatment with transarterial chemoembolization (TACE).

MATERIALS AND METHODS

HCCLM3 and Huh-7 cells were adopted to evaluate the effect of tumor proliferation, migration, and invasion after RLX administration in vitro. The rabbit VX2 model was used to evaluate the biosafety, doxorubicin penetration, local tumor response, tumor metastasis, and survival benefit of RLX combined with TACE treatment.

RESULTS

RLX did not affect the proliferation, migration, or invasion of HCCLM3 and Huh-7 cells, and the expression of E-cadherin and HIF-1α also remained unchanged while the MMP-9 protein was upregulated in vitro. In the rabbit VX2 model, compared to the normal saline group (NS), RLX group (RLX) and TACE mono-therapy group (TACE), the group that received TACE combined with RLX (TACE + RLX) showed an improved local tumor response and survival benefit. Furthermore, TACE combined with RLX was found to reduce tumor metastasis. This combination therapy reduced the fibrotic extracellular matrix in the tumor microenvironment, allowing for better penetration of doxorubicin, improved infiltration of CD8+ T cells and affected the secretion of cytokines. Additionally, RLX combined with TACE was able to decrease the expression of HIF-1α and PD-L1. The biosafety of TACE combined with RLX was also confirmed.

CONCLUSION

RLX synergized with TACE by mitigating the fibrotic extracellular matrix and tumor hypoxic microenvironment, improving the therapeutic effect and inhibiting metastasis during the treatment of liver cancer.

Clinical Advances in Triple Negative Breast Cancer Treatment: Focus on Poly (L-lactide-coglycolide) Nanoparticles

Triple negative breast cancer (TNBC) is the most aggressive type of breast cancer and is associated with high probability of metastasis and poor prognosis. Chemotherapeutics and surgery remain the most common options for TNBC patients; however, chemotherapeutic resistance and relapse of tumors limit the progression free survival and patient life span. This review provides an overview of recent chemotherapeutics that are in clinical trial, and the combination of drugs that are being investigated to overcome the drug resistance and to improve patient survival in different molecular subtypes of TNBCs. Nanotherapeutics have emerged as a promising platform for TNBC treatment and aim to improve the selectivity and solubility of drugs, reduce systemic side effects, and overcome multi-drug resistance. The study explores the role of nanoparticles for TNBC treatment and summarizes the types of nanoparticles that are in clinical trials. Poly(L-lactide-co-glycolide) (PLGA) is the most studied polymeric carrier for drug delivery and for TNBC treatment in research and in clinics. This review is about providing recent advancements in PLGA nanotherapeutic formulations and their application to help treat TNBC. Some background on current chemotherapies and pathway inhibitors is provided so that the readers are aware of what is currently considered for TNBC. Some of the pathway inhibitors may also be of importance for nanotherapeutics development. SIGNIFICANCE STATEMENT: This minireview summarizes the progress on chemotherapeutics and nanoparticle delivery for treatment of TNBC and specifically highlights the lead compounds that are in clinical trials.

Nanoparticle-Mediated Immunotherapy in Triple-Negative Breast Cancer

Triple-negative breast cancer (TNBC) is an aggressive subtype with the worst prognosis and highest recurrence rates. The treatment choices are limited due to the scarcity of endocrine and HER2 targets, except for chemotherapy. However, the side effects of chemotherapy restrict its long-term usage. Immunotherapy shows potential as a promising therapeutic strategy, such as inducing immunogenic cell death, immune checkpoint therapy, and immune adjuvant therapy. Nanotechnology offers unique advantages in the field of immunotherapy, such as improved delivery and targeted release of immunotherapeutic agents and enhanced bioavailability of immunomodulators. As well as the potential for combination therapy synergistically enhanced by nanocarriers. Nanoparticles-based combined application of multiple immunotherapies is designed to take the tactics of enhancing immunogenicity and reversing immunosuppression. Moreover, the increasing abundance of biomedical materials holds more promise for the development of this field. This review summarizes the advances in the field of nanoparticle-mediated immunotherapy in terms of both immune strategies for treatment and the development of biomaterials and presents challenges and hopes for the future.

Nano-Drug Delivery Systems Targeting CAFs: A Promising Treatment for Pancreatic Cancer

Currently, pancreatic cancer (PC) is one of the most lethal malignant tumors. PC is typically diagnosed at a late stage, exhibits a poor response to conventional treatment, and has a bleak prognosis. Unfortunately, PC's survival rate has not significantly improved since the 1960s. Cancer-associated fibroblasts (CAFs) are a key component of the pancreatic tumor microenvironment (TME). They play a vital role in maintaining the extracellular matrix and facilitating the intricate communication between cancer cells and infiltrated immune cells. Exploring therapeutic approaches targeting CAFs may reverse the current landscape of PC therapy. In recent years, nano-drug delivery systems have evolved rapidly and have been able to accurately target and precisely release drugs with little or no toxicity to the whole body. In this review, we will comprehensively discuss the origin, heterogeneity, potential targets, and recent advances in the nano-drug delivery system of CAFs in PC. We will also propose a novel integrated treatment regimen that utilizes a nano-drug delivery system to target CAFs in PC, combined with radiotherapy and immunotherapy. Additionally, we will address the challenges that this regimen currently faces.

Targeting triple negative breast cancer stem cells using nanocarriers

Breast cancer is a complex and heterogeneous disease, encompassing various subtypes characterized by distinct molecular features, clinical behaviors, and treatment responses. Categorization of subtypes is based on the presence or absence of estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2), leading to subtypes such as luminal A, luminal B, HER2-positive, and triple-negative breast cancer (TNBC). TNBC, comprising around 20% of all breast cancers, lacks expression of ER, PR, and HER2 receptors, rendering it unresponsive to targeted therapies and presenting significant challenges in treatment. TNBC is associated with aggressive behavior, high rates of recurrence, and resistance to chemotherapy. Tumor initiation, progression, and treatment resistance in TNBC are attributed to breast cancer stem cells (BCSCs), which possess self-renewal, differentiation, and tumorigenic potential. Surface markers, self-renewal pathways (Notch, Wnt, Hedgehog signaling), apoptotic protein (Bcl-2), angiogenesis inhibition (VEGF inhibitors), and immune modulation (cytokines, immune checkpoint inhibitors) are among the key targets discussed in this review. However, targeting the BCSC subpopulation in TNBC presents challenges, including off-target effects, low solubility, and bioavailability of anti-BCSC agents. Nanoparticle-based therapies offer a promising approach to target various molecular pathways and cellular processes implicated in survival of BSCS in TNBC. In this review, we explore various nanocarrier-based approaches for targeting BCSCs in TNBC, aiming to overcome these challenges and improve treatment outcomes for TNBC patients. These nanoparticle-based therapeutic strategies hold promise for addressing the therapeutic gap in TNBC treatment by delivering targeted therapies to BCSCs while minimizing systemic toxicity and enhancing treatment efficacy.