The emerging role of immune checkpoint inhibitors for the treatment of breast cancer

Intratumoral delivery of immunotherapy to treat breast cancer: current development in clinical and preclinical studies

Breast cancer poses one of the largest threats to women's health. Treatment continues to improve for all the subtypes of breast cancer, but some subtypes, such as triple negative breast cancer, still present a significant treatment challenge. Additionally, metastasis and local recurrence are two prevalent problems in breast cancer treatment. A newer type of therapy, immunotherapy, may offer alternatives to traditional treatments for difficult-to-treat subtypes. Immunotherapy engages the host's immune system to eradicate disease, with the potential to induce long-lasting, durable responses. However, systemic immunotherapy is only approved in a limited number of indications, and it benefits only a minority of patients. Furthermore, immune related toxicities following systemic administration of potent immunomodulators limit dosing and, consequently, efficacy. To address these safety considerations and improve treatment efficacy, interest in local delivery at the site of the tumor has increased. Numerous intratumorally delivered immunotherapeutics have been and are being explored clinically and preclinically, including monoclonal antibodies, cellular therapies, viruses, nucleic acids, cytokines, innate immune agonists, and bacteria. This review summarizes the current and past intratumoral immunotherapy clinical landscape in breast cancer as well as current progress that has been made in preclinical studies, with a focus on delivery parameters and considerations.

Marine seaweed endophytic fungi-derived active metabolites promote reactive oxygen species-induced cell cycle arrest and apoptosis in human breast cancer cells

BACKGROUND

Endophytic fungi have an abundant sources rich source of rich bioactive molecules with pivotal pharmacological properties. Several studies have found that endophytic fungi-derived bioactive secondary metabolites have antiproliferative, anti-oxidant, and anti-inflammatory properties, but the molecular mechanism by which they induce cell cycle arrest and apoptosis pathways is unknown. This study aimed to determine the molecular mechanism underlying the anticancer property of the endophytic fungi derived active secondary metabolites on human breast cancer cells.

METHODS

In this study, we identified four endophytic fungi from marine seaweeds and partially screened its phytochemical properties by Chromatography-Mass Spectrometry (GC-MS) analysis. Moreover, the molecular mechanism underlying the anticancer property of these active secondary metabolites (FA, FB, FC and FE) on human breast cancer cells were examined on MCF-7 cells by TT assay, Apoptotic assay by Acridine orang/Ethidium Bromide (Dual Staining), DNA Fragmentation by DAPI Staining, reactive oxygen species (ROS) determination by DCFH-DA assay, Cell cycle analysis was conducted Flow cytometry and the apoptotic signalling pathway was evaluated by westernblot analysis. Doxorubicin was used as a positive control drug for this experiment.

RESULTS

The GC-MS analysis of ethyl acetate extract of endophytic fungi from the marine macro-algae revealed the different functional groups and bioactive secondary metabolites. From the library, we observed the FC (76%), FB (75%), FA (73%) and FE (71%) have high level of antioxidant activity which was assessed by DPPH scavenging assay. Further, we evaluated the cytotoxic potentials of these secondary metabolites on human breast cancer MCF-7 cells for 24 h and the IC50 value were calculated (FA:28.62 ± 0.3 µg/ml, FB:49.81 ± 2.5 µg/ml, FC:139.42 ± µg/ml and FE:22.47 ± 0.5 µg/ul) along with positive control Doxorubicin 15.64 ± 0.8 µg/ml respectively by MTT assay. The molecular mechanism by which the four active compound induced apoptosis via reactive oxygen species (ROS) and cell cycle arrest in MCF-7 cells was determined H2DCFDA staining, DAPI staining, Acridine orange and ethidium bromide (AO/EtBr) dual staining, flowcytometry analysis with PI staining and apoptotic key regulatory proteins expression levels measured by westernblot analysis.

CONCLUSION

Our findings, revealed the anticancer potential of endophytic fungi from marine seaweed as a valuable source of bioactive compounds with anticancer properties and underscore the significance of exploring marine-derived endophytic fungi as a promising avenue for the development of novel anticancer agents. Further investigations are necessary to isolate and characterize specific bioactive compounds responsible for these effects and to validate their therapeutic potential in preclinical and clinical settings.

Suppression of B7-H7 Enhanced MCF-7 Cancer Cell Line's Chemosensitivity to Paclitaxel

The B7-H7 is the newest addition to the B7 family of proteins that is present in the majority of malignancies. In this respect, the goal of the work was to investigate the impact of B7-H7 inhibition on breast cancer cells when paclitaxel and small interference RNA (siRNA) were combined. B7-H7 siRNA was used with Paclitaxel to treat MCF-7 cells. The IC50 of Paclitaxel and the cell survival was then assessed through using MTT assay. Investigation was conducted using flow cytometry to both the induction of apoptosis and the cell cycle. In addition, the clonogenic capacity of MCF-7 cells was investigated. Furthermore, qRT-PCR, was used to evaluate expression of genes. Our results demonstrated that suppressing B7-H7 sensitizes MCF-7 cells to Paclitaxel by triggering apoptosis and altering the expression of critical apoptosis mediator genes. In addition, the cell cycle was stopped in the sub-G1 and also G2-M phases as a result of the combination therapy leading prevention of developing colonies by MCF-7 cells. B7-H7 silencing improved the chemosensitivity of MCF-7 cells to Paclitaxel and demonstrated antiproliferative effects. After the adequate study has been conducted, this strategy may be regarded as a possible alternative treatment option for this cancer.

Novel immunotherapies for breast cancer: Focus on 2023 findings

Immunotherapy has emerged as a revolutionary approach in cancer therapy, and recent advancements hold significant promise for breast cancer (BCa) management. Employing the patient's immune system to combat BCa has become a focal point in immunotherapeutic investigations. Strategies such as immune checkpoint inhibitors (ICIs), adoptive cell transfer (ACT), and targeting the tumor microenvironment (TME) have disclosed encouraging clinical outcomes. ICIs, particularly programmed cell death protein 1 (PD-1)/PD-L1 inhibitors, exhibit efficacy in specific BCa subtypes, including triple-negative BCa (TNBC) and human epidermal growth factor receptor 2 (HER2)-positive cancers. ACT approaches, including tumor-infiltrating lymphocytes (TILs) and chimeric antigen receptor (CAR) T-cell therapy, showed promising clinical outcomes in enhancing tumor recognition and elimination. Targeting the TME through immune agonists and oncolytic viruses signifies a burgeoning field of research. While challenges persist in patient selection, resistance mechanisms, and combination therapy optimization, these novel immunotherapies hold transformative potential for BCa treatment. Continued research and clinical trials are imperative to refine and implement these innovative approaches, paving the way for improved outcomes and revolutionizing the management of BCa. This review provides a concise overview of the latest immunotherapies (2023 studies) in BCa, highlighting their potential and current status.

Core Needle Biopsies as an Alternative Source for Ex Vivo Expanded TIL for Adoptive Cell Therapy in Triple-Negative Breast Cancer

Adoptive transfer of ex vivo expanded tumor-infiltrating lymphocytes (TILs) have produced long-term response in metastatic cancers. TILs have traditionally been expanded from surgically resected specimens. Ultrasound-guided core needle biopsy (CNB) is an alternative method that avoids the morbidity of surgery and have added benefits which may include patients not amenable to surgery as well as the potential to produce TILs from multiple lesions in the same patient. We assessed the ability to produce and expand TILs from primary triple-negative breast cancer tumors from CNB (n=7) and demonstrate comparable expansion, phenotype and cytokine secretion after phorbol myristate acetate-ionomycin stimulation to TILs expanded from surgery (n=6). T cell Receptor clonality and diversity were also comparable between the two cohorts throughout the TIL culture. CNB is a safe and feasible method to obtain tumor tissue for TIL generation in patients with triple-negative breast cancer.

Current status and future prospective of breast cancer immunotherapy

The immune system is complicated, interconnected, and offers a powerful defense system that protects its host from foreign pathogens. Immunotherapy involves boosting the immune system to kill cancer cells, and nowadays, is a major emerging treatment for cancer. With the advances in our understanding of the immunology of cancer, there has been an explosion of studies to develop and evaluate therapies that engage the immune system in the fight against cancer. Nevertheless, conventional therapies have been effective in reducing tumor burden and prolonging patient life, but the overall efficacy of these treatment regimens has been somewhat mixed and often with severe side effects. A common reason for this is the activation of molecular mechanisms that lead to apoptosis of anti-tumor effector cells. The competency to block tumor escape entirely depends on our understanding of the cellular and molecular pathways which operate in the tumor microenvironment. Numerous strategies have been developed for activating the immune system to kill tumor cells. Breast cancer is one of the major causes of cancer death in women, and is characterized by complex molecular and cellular events that closely intertwine with the host immune system. In this regard, predictive biomarkers of immunotherapy, use of nanotechnology, personalized cancer vaccines, antibodies to checkpoint inhibitors, engineered chimeric antigen receptor-T cells, and the combination with other therapeutic modalities have transformed cancer therapy and optimized the therapeutic effect. In this chapter, we will offer a holistic view of the different therapeutic modalities and recent advances in immunotherapy. Additionally, we will summarize the recent advances and future prospective of breast cancer immunotherapies, as a case study.

Unveiling the Immune Microenvironment's Role in Breast Cancer: A Glimpse into Promising Frontiers

Breast cancer (BC), one of the most widespread and devastating diseases affecting women worldwide, presents a significant public health challenge. This review explores the emerging frontiers of research focused on deciphering the intricate interplay between BC cells and the immune microenvironment. Understanding the role of the immune system in BC is critical as it holds promise for novel therapeutic approaches and precision medicine strategies. This review delves into the current literature regarding the immune microenvironment's contribution to BC initiation, progression, and metastasis. It examines the complex mechanisms by which BC cells interact with various immune cell populations, including tumor-infiltrating lymphocytes (TILs) and tumor-associated macrophages (TAMs). Furthermore, this review highlights the impact of immune-related factors, such as cytokines and immune checkpoint molecules. Additionally, this comprehensive analysis sheds light on the potential biomarkers associated with the immune response in BC, enabling early diagnosis and prognostic assessment. The therapeutic implications of targeting the immune microenvironment are also explored, encompassing immunotherapeutic strategies and combination therapies to enhance treatment efficacy. The significance of this review lies in its potential to pave the way for novel therapeutic interventions, providing clinicians and researchers with essential knowledge to design targeted and personalized treatment regimens for BC patients.

Clinical Considerations for the Integration of Adjuvant Olaparib into Practice for Early Breast Cancer: A Canadian Perspective

With the recent Health Canada approval of olaparib for high-risk, HER2-negative early breast cancer, physicians are now facing the practical challenges of integrating olaparib into current management of triple-negative breast cancer (TNBC) and HR-positive, HER2-negative (HR+/HER2-) early breast cancer. This review provides perspectives on some of the challenges related to identification of olaparib candidates, with a focus on the latest guidance for germline BRCA testing and considerations regarding high-risk disease definitions. Updated treatment pathways are explored for both disease states, including other adjuvant treatment options such as pembrolizumab, capecitabine, and abemaciclib. Gaps in the current literature regarding the sequential or combined use of these adjuvant therapies are noted and future, potentially informative, studies are briefly examined.

Recent Advances with Precision Medicine Treatment for Breast Cancer including Triple-Negative Sub-Type

Breast cancer is a heterogeneous disease with different molecular subtypes. Breast cancer is the second leading cause of mortality in woman due to rapid metastasis and disease recurrence. Precision medicine remains an essential source to lower the off-target toxicities of chemotherapeutic agents and maximize the patient benefits. This is a crucial approach for a more effective treatment and prevention of disease. Precision-medicine methods are based on the selection of suitable biomarkers to envision the effectiveness of targeted therapy in a specific group of patients. Several druggable mutations have been identified in breast cancer patients. Current improvements in omics technologies have focused on more precise strategies for precision therapy. The development of next-generation sequencing technologies has raised hopes for precision-medicine treatment strategies in breast cancer (BC) and triple-negative breast cancer (TNBC). Targeted therapies utilizing immune checkpoint inhibitors (ICIs), epidermal growth factor receptor inhibitor (EGFRi), poly(ADP-ribose) polymerase inhibitor (PARPi), antibody-drug conjugates (ADCs), oncolytic viruses (OVs), glucose transporter-1 inhibitor (GLUT1i), and targeting signaling pathways are potential treatment approaches for BC and TNBC. This review emphasizes the recent progress made with the precision-medicine therapy of metastatic breast cancer and TNBC.

Defining the Emergence of New Immunotherapy Approaches in Breast Cancer: Role of Myeloid-Derived Suppressor Cells

Breast cancer (BC) continues to be the most diagnosed tumor in women and a very heterogeneous disease both inter- and intratumoral, mainly given by the variety of molecular profiles with different biological and clinical characteristics. Despite the advancements in early detection and therapeutic strategies, the survival rate is low in patients who develop metastatic disease. Therefore, it is mandatory to explore new approaches to achieve better responses. In this regard, immunotherapy arose as a promising alternative to conventional treatments due to its ability to modulate the immune system, which may play a dual role in this disease since the relationship between the immune system and BC cells depends on several factors: the tumor histology and size, as well as the involvement of lymph nodes, immune cells, and molecules that are part of the tumor microenvironment. Particularly, myeloid-derived suppressor cell (MDSC) expansion is one of the major immunosuppressive mechanisms used by breast tumors since it has been associated with worse clinical stage, metastatic burden, and poor efficacy of immunotherapies. This review focuses on the new immunotherapies in BC in the last five years. Additionally, the role of MDSC as a therapeutic target in breast cancer will be described.

The Combination of Immune Checkpoint Blockade with Tumor Vessel Normalization as a Promising Therapeutic Strategy for Breast Cancer: An Overview of Preclinical and Clinical Studies

Immune checkpoint inhibitors (ICIs) have a modest clinical activity when administered as monotherapy against breast cancer (BC), the most common malignancy in women. Novel combinatorial strategies are currently being investigated to overcome resistance to ICIs and promote antitumor immune responses in a greater proportion of BC patients. Recent studies have shown that the BC abnormal vasculature is associated with immune suppression in patients, and hampers both drug delivery and immune effector cell trafficking to tumor nests. Thus, strategies directed at normalizing (i.e., at remodeling and stabilizing) the immature, abnormal tumor vessels are receiving much attention. In particular, the combination of ICIs with tumor vessel normalizing agents is thought to hold great promise for the treatment of BC patients. Indeed, a compelling body of evidence indicates that the addition of low doses of antiangiogenic drugs to ICIs substantially improves antitumor immunity. In this review, we outline the impact that the reciprocal interactions occurring between tumor angiogenesis and immune cells have on the immune evasion and clinical progression of BC. In addition, we overview preclinical and clinical studies that are presently evaluating the therapeutic effectiveness of combining ICIs with antiangiogenic drugs in BC patients.

Pathology of neoadjuvant therapy and immunotherapy testing for breast cancer

Neoadjuvant chemotherapy (NACT) has become the standard of care for high-risk breast cancer, including triple-negative (TNBC) and HER2-positive disease. As a result, handling and reporting of breast specimens post-NACT is part of routine practice, and it is important for pathologists to recognise the changes in tumour cells, tumour-associated stroma and background breast tissue induced by NACT. Familiarity with characteristic stromal features enables identification of the pre-treatment tumour site and allows confident diagnosis of pathological complete response (pCR) which is important for decisions concerning adjuvant therapy. Neoadjuvant endocrine therapy (NAET) is used less frequently than NACT; however, the SARS-COVID-19 pandemic has changed practice, with increased use as bridging therapy if surgery is delayed. NAET also induces characteristic changes in the tumour and stroma. Changes in the tumour microenvironment following NACT and NAET are also described. Immunotherapy is approved for use in advanced TNBC, and there are several trials exploring its role in early TNBC in the neoadjuvant setting. The current biomarker to determine eligibility for treatment with immune checkpoint inhibitors is programmed death ligand-1 (PD-L1) immunohistochemistry; however, this is complicated by lack of standardisation with different drugs linked to tests using different antibodies with different scoring systems. The situation in the neoadjuvant setting is further complicated by improved pCR rates for PD-L1-positive tumours in both immune therapy and placebo arms. Alternative biomarkers are urgently needed to identify which patients will derive benefit from immunotherapy and key candidates are discussed.

Immune Checkpoint Inhibitors and Other Immune Therapies in Breast Cancer: A New Paradigm for Prolonged Adjuvant Immunotherapy

Background: Breast cancer is the most common form of cancer in women worldwide. Advances in the early diagnosis and treatment of cancer in the last decade have progressively decreased the cancer mortality rate, and in recent years, immunotherapy has emerged as a relevant tool against cancer. HER2+ and triple-negative breast cancers (TNBCs) are considered more immunogenic and suitable for this kind of treatment due to the higher rate of tumor-infiltrating lymphocytes (TILs) and programmed death ligand 1 (PD-L1) expression. In TNBC, genetic aberrations further favor immunogenicity due to more neo-antigens in cancer cells. Methods: This review summarizes the principal ongoing conventional and investigational immunotherapies in breast cancer. Particularly, immune checkpoint inhibitors (ICIs) and their use alone or combined with DNA damage repair inhibitors (DDRis) are described. Then, the issue on immunotherapy with monoclonal antibodies against HER-2 family receptors is updated. Other investigational immunotherapies include a new schedule based on the interferon beta-interleukin-2 sequence that was given in ER+ metastatic breast cancer patients concomitant with anti-estrogen therapy, which surprisingly showed promising results. Results: Based on the scientific literature and our own findings, the current evaluation of tumor immunogenicity and the conventional model of adjuvant chemotherapy (CT) are questioned. Conclusions: A novel strategy based on additional prolonged adjuvant immunotherapy combined with hormone therapy or alternated with CT is proposed.

Usefulness of Hounsfield Units and the Serum Neutrophil-to-Lymphocyte Ratio as Prognostic Factors in Patients with Breast Cancer

Breast cancer is a leading cause of death worldwide. Tumor vascularity and immune disturbances are hallmarks of cancer. This study aimed to investigate the reciprocal effect of tumor vascularity, assessed by the tumor-to-aorta ratio (TAR) of Hounsfield units (HU) on computed tomography (CT), and host immunity, represented by the serum neutrophil-to-lymphocyte ratio (NLR) from peripheral, complete blood cell counts and its impact on patient survival. Female patients with breast cancer who received primary treatment between 2003 and 2018 at Wonju Severance Hospital, Korea, were included. The final cohort included 740 patients with a mean age of 54.3 ± 11.3 (22−89) years. The TAR was 0.347 ± 0.108 (range, 0.062−1.114) and the NLR was 2.29 ± 1.53 (0.61−10.47). The cut-off value for the TAR and NLR were 0.27 and 1.61, respectively. The patients with a TAR > 0.27 showed a poor recurrence free-interval (RFI) only when their NLR was larger than 1.61, and vice versa. The patients showed worse RFI when they had both high TAR and NLR. Our results suggest a dynamic reciprocal communication between tumor vascularity and systemic immunity.

Which role for predictors of response to immune checkpoint inhibitors in hepatocellular carcinoma?

INTRODUCTION

Hepatocellular carcinoma (HCC) remains a frequently diagnosed malignancy worldwide, still representing an important cause of cancer-related death. Recent years have seen the emergence of novel systemic treatments for HCC patients, including immune checkpoint inhibitors (ICIs). Nonetheless, several questions regarding HCC immunotherapy remain unanswered, especially in terms of biochemical predictors of response.

AREAS COVERED

In the current paper, we will discuss available evidence regarding predictive biomarkers of response to HCC immunotherapy. A literature search was conducted in January 2022 of Pubmed/Medline, Cochrane library, and Scopus databases.

EXPERT OPINION

The identification of predictive biomarkers represents an unmet need in HCC patients receiving ICIs. The HCC medical community is called to further efforts aimed to elucidate the effective role of PD-L1 expression, TMB, MSI, gut microbiota, and other emerging biomarkers.