Emerging immunotherapy strategies in breast cancer

Pharmacological disruption of the MTDH-SND1 complex enhances tumor antigen presentation and synergizes with anti-PD-1 therapy in metastatic breast cancer

Despite increased overall survival rates, curative options for metastatic breast cancer remain limited. We have previously shown that metadherin (MTDH) is frequently overexpressed in poor prognosis breast cancer, where it promotes metastasis and therapy resistance through its interaction with staphylococcal nuclease domain-containing 1 (SND1). Through genetic and pharmacological targeting of the MTDH-SND1 interaction, we reveal a key role for this complex in suppressing antitumor T cell responses in breast cancer. The MTDH-SND1 complex reduces tumor antigen presentation and inhibits T cell infiltration and activation by binding to and destabilizing Tap1/2 messenger RNAs, which encode key components of the antigen-presentation machinery. Following small-molecule compound C26-A6 treatment to disrupt the MTDH-SND1 complex, we showed enhanced immune surveillance and sensitivity to anti-programmed cell death protein 1 therapy in preclinical models of metastatic breast cancer, in support of this combination therapy as a viable approach to increase immune-checkpoint blockade therapy responses in metastatic breast cancer.

PDL1 expression is associated with longer postoperative, survival in adrenocortical carcinoma

Adrenocortical carcinomas (ACCs) are heterogeneous cancers associated with a very poor prognosis. The improvement of prognostic tools and systemic therapy are urgently needed. Targeting the immune system using checkpoint inhibitors such as PD1/PDL1 inhibitors is an attractive novel therapeutic strategy for poor-prognosis tumors. Multiple clinical trials are ongoing, including in advanced ACC. However, PDL1 expression has been studied in ACC in only one heterogeneous series of 28 clinical samples. Here, we have retrospectively analyzed PDL1 mRNA expression in 146 clinical ACC samples and searched for correlations between expression and biological and clinicopathological data, including post-operative disease-free survival (DFS). PDL1 mRNA expression was heterogeneous across samples. "PDL1-high" tumors were not associated with the classical prognostic variables but were associated with longer DFS in both uni- and multivariate analyses. High PDL1 mRNA expression was associated with biological signs of the cytotoxic local immune response. Supervised analysis between "PDL1-high" and "PDL1-low" tumors identified a robust 370-gene signature whose ontology analysis suggested the existence in "PDL1-high" tumors of a cytotoxic T-cell response, however, associated with some degree of T-cell exhaustion. In conclusion, PDL1 mRNA expression refines the prognostication in ACC and high expression is associated with longer DFS. Clinical validation at the protein level and functional validation are required to fully understand the role of PDL1 in ACC. Reactivation of dormant tumor-infiltrating lymphocytes by PDL1-inhibitors could represent a promising strategy in "PDL1-high" ACCs, supporting the ongoing clinical trials.

Immunotherapy for HER2-positive breast cancer: recent advances and combination therapeutic approaches

Cancer immunotherapy has evolved dramatically with improved understanding of immune microenvironment and immunosurveillance. The immunogenicity of breast cancer is rather heterogeneous. Specific subtypes of breast cancer such as estrogen receptor (ER)-negative, human EGF receptor 2 (HER2)-positive, and triple-negative breast cancer (TNBC) have shown evidence of immunogenicity based on tumor–immune interactions. Several preclinical and clinical studies have explored the potential for immunotherapy to improve the clinical outcomes for different subtypes of breast cancer. This review describes the immune microenvironment of HER2-positive breast cancer and summarizes recent clinical advances of immunotherapeutic treatments in this breast cancer subtype. The review provides rationale and ongoing clinical evidence to the use of immune checkpoint inhibitors, therapeutic vaccines, and adoptive T cell immunotherapy in breast cancer. In addition, the present paper describes the most relevant clinical progress of strategies for the combination of immunotherapy with standard treatment modalities in HER2-positive breast cancer including chemotherapy, targeted therapy, and radiotherapy.

The Impact of microRNAs in Breast Cancer Angiogenesis and Progression

OBJECTIVE

The study aims to review the recent data considering the expression profile and the role of microRNAs in breast tumorigenesis, and their impact on -the vital for breast cancer progression- angiogenesis.

METHODS

PubMed was searched for studies focused on data that associate microRNA with breast cancer, using the terms ''breast", "mammary gland", "neoplasia'', "angiogenesis" and ''microRNA'' between 1997-2018.

RESULTS

Aberrant expression of several circulating and tissue miRNAs is observed in human breast neoplasms with the deregulation of several miRNAs having a major participation in breast cancer progression. Angiogenesis seems to be directly affected by either overexpression or down regulation of many miRNAs, defining the overall prognostic rates. Many miRNAs differentially expressed in breast cancer that reveal a key role in suppression - progression and metastasis of breast cancer along with the contribution of the EGF, TNF-a and EGF cytokines. Conclusion Angiogenesis has proven to be vital for tumor development and metastasis while microRNAs are proposed to have multiple biological roles, including participation in immunosuppressive, immunomodulatory and recent studies reveal their implication in angiogenesis and its possible use as prognostic factors in cancer Even though larger studies are needed in order to reach safe conclusions, important steps are made that reveal the connection of serum microRNA expression to the angiogenic course of breast cancer, while miRNAs could be potential prognostic factors for the different breast cancer types.

Breast cancer stem cell markers CD44 and ALDH1A1 in serum: distribution and prognostic value in patients with primary breast cancer

Background: CD44 and ALDH1 have been recognized as the most widely used markers to identify breast cancer stem cells (BCSCs). However, limited to tissue sample and rare population, BCSCs have always been not easily detected. We aimed to measure CD44 and ALDH1A1 (major contributor to ALDH1 activity) levels in serum and explore the prognostic value in primary breast cancer patients.

Methods: This study included 140 primary breast cancer patients with stage I-III. Serum samples were collected before surgery and stored at -80 degrees. CD44 and ALDH1A1 were measured by chemiluminescent assay.

Results: High serum CD44 levels (≥ 417.4 ng/mL) were correlated with postmenopausal status (P = 0.006), estrogen receptor negativity (P = 0.025), progesterone receptor negativity (P = 0.002) and adjuvant chemotherapy (P = 0.003). The mean serum CD44 levels of luminal group (406.4 ± 68.3 ng/mL) were significantly lower than triple negative group (506.8 ± 175.5 ng/mL) (P < 0.001). There was no correlation between serum ALDH1A1 levels and molecular subtypes. Multivariate analysis revealed that high serum CD44 level (≥ 417.4 ng/mL), was an independent factor for PFS (P = 0.019) and OS (P = 0.008). However, serum ALDH1A1 has no impact on either PFS (P = 0.613) or OS (P = 0.441).

Conclusion: Serum CD44 was an independent prognostic indicator in primary breast cancer. However, serum ALDH1A1 has no impact on survivals and might not be an appropriate candidate to predict prognosis for breast cancer.

Tumor cryoablation in combination with natural killer cells therapy and Herceptin in patients with HER2-overexpressing recurrent breast cancer

In this study, we investigated the clinical benefits of a combination of tumor cryoablation with natural killer (NK) cells therapy and Herceptin for human epidermal growth factor (HER) 2-overexpressing recurrent breast cancer. From May 2015 to May 2016, 48 patients who met the enrollment criteria were assigned to three groups (n=16): cryoablation group (group I), cryoablation-NK cells therapy group (group II) and cryoablation-NK cells therapy-Herceptin group (group III). Safety and short-term effects were evaluated. All the adverse effects were manageable and acceptable. The three-therapy combination treatment not only yielded good clinical efficacy, it also improved the quality of life; reduced levels of circulating tumor cells (CTCs); reduced carcino-embryonic antigen (CEA) and cancer antigen 15-3 (CA15-3) expression; enhanced immune function significantly. Furthermore, it can resulte in significant prolongation of progression free survival (PFS). This is the first clinical study to demonstrate the benefit of the three-therapy combination of tumor cryoablation, NK cells therapy, and Herceptin for HER2-overexpressing recurrent breast cancer.

Comparison of autogeneic and allogeneic natural killer cells immunotherapy on the clinical outcome of recurrent breast cancer

In the present study, we aimed to compare the clinical outcome of autogeneic and allogeneic natural killer (NK) cells immunotherapy for the treatment of recurrent breast cancer. Between July 2016 and February 2017, 36 patients who met the enrollment criteria were randomly assigned to two groups: autogeneic NK cells immunotherapy group (group I, n=18) and allogeneic NK cells immunotherapy group (group II, n=18). The clinical efficacy, quality of life, immune function, circulating tumor cell (CTC) level, and other related indicators were evaluated. We found that allogeneic NK cells immunotherapy has better clinical efficacy than autogeneic therapy. Moreover, allogeneic NK cells therapy improves the quality of life, reduces the number of CTCs, reduces carcinoembryonic antigen and cancer antigen 15-3 (CA15-3) expression, and significantly enhances immune function. To our knowledge, this is the first clinical trial to compare the clinical outcome of autogeneic and allogeneic NK cells immunotherapy for recurrent breast cancer.

Cryoablation combined with allogenic natural killer cell immunotherapy improves the curative effect in patients with advanced hepatocellular cancer

In this study, the clinical efficacy of cryosurgery combined with allogenic natural killer cell immunotherapy for advanced hepatocellular cancer was evaluated. From October 2015 to March 2017, we enrolled 61 patients who met the enrollment criteria and divided them into two groups: 1) the simple cryoablation group (Cryo group, n = 26); and 2) the cryoablation combined with allogenic natural killer cells group (Cryo-NK group, n = 35), the safety and short-term effects were evaluated firstly, then the median progression-free survival, response rate and disease control rate were assessed. All adverse events experienced by the patients were recorded, and included local (e.g., pain, pleural effusion, and ascites) and systemic (e.g., chills, fatigue, and fever) reactions, fever was more frequent. Other possible seriously side effects (e.g., blood or bone marrow changes) were not detected. Combining allogeneic natural killer cells with cryoablation had a synergistic effect, not only enhancing the immune function, improving the quality of life of the patients, but also reducing the expression of AFP and significantly exhibiting good clinical efficacy of the patients. After a median follow-up of 8.7 months (3.9 -15.1months), median progression-free survival was higher in Cryo-NK (9.1 months) than in Cryo (7.6 months, P = 0.0107), median progression-free survival who received multiple natural killer was higher than who just received single natural killer (9.7 months vs.8.4 months, P = 0.0011, respectively), the response rate in Cryo-NK (60.0%) was higher than in Cryo (46.1%, P < 0.05), the disease control rate in Cryo-NK (85.7%) was higher than in Cryo group (69.2%, P < 0.01). Percutaneous cryoablation combined with allogeneic natural killer cell immunotherapy significantly increased median progression-free survival of advanced hepatocellular cancer patients. Multiple allogeneic natural killer cells infusion was associated with better prognosis to advanced hepatocellular cancer.

Immunotherapy in breast cancer: An overview of modern checkpoint blockade strategies and vaccines

Immune therapy has recently emerged as a standard-of-care strategy for the treatment of melanoma, lung cancer, bladder cancer, among other malignancies. However, the role of immune therapy in the treatment of breast cancer is still being determined. Two current strategies for harnessing the immune system to treat cancer include drugs that modulate key T cell inhibitory checkpoints and vaccines. Specifically, modern immune therapy strategies can facilitate T-cell mediated tumor regression by priming the immune system against specific tumor associated antigens, by modulating immunoregulatory signals, or both. In breast cancer, preliminary data from preclinical and early clinical studies are promising. In fact, clinical data with checkpoint blockade as monotherapy has been reported in multiple breast cancer subtypes to date, with durable responses observed in a significant proportion of women with chemotherapy resistant disease. However, because the number of genetic mutations and thus, the number of neoantigens available for immune response are modest in most breast cancers when compared with other cancers, most breast cancers may not be inherently sensitive to immune modulation and therefore may require strategies that enhance tumor associated antigen presentation if immune modulation strategies are to be effective. To that end, studies that combine checkpoint blockade with other strategies including established systemic therapies (including hormone therapy and chemotherapy), radiation therapy, and localized therapy including tumor freezing (cryoablation) are underway in breast cancer. Studies that combine checkpoint blockade with vaccines are also planned. Herein, we provide a brief summary of key components of the immune response against cancer, a rationale for the use of immune therapy in breast cancer, data from early clinical trials of checkpoint blockade and vaccine strategies in breast cancer, and future directions in the field.

Emerging therapeutic targets in metastatic progression: A focus on breast cancer

Metastasis is the underlying cause of death for the majority of breast cancer patients. Despite significant advances in recent years in basic research and clinical development, therapies that specifically target metastatic breast cancer remain inadequate, and represents the single greatest obstacle to reducing mortality of late-stage breast cancer. Recent efforts have leveraged genomic analysis of breast cancer and molecular dissection of tumor-stromal cross-talk to uncover a number of promising candidates for targeted treatment of metastatic breast cancer. Rational combinations of therapeutic agents targeting tumor-intrinsic properties and microenvironmental components provide a promising strategy to develop precision treatments with higher specificity and less toxicity. In this review, we discuss the emerging therapeutic targets in breast cancer metastasis, from tumor-intrinsic pathways to those that involve the host tissue components, including the immune system.

TNF is a key cytokine mediating neutrophil cytotoxic activity in breast cancer patients

We have previously shown a novel antimetastatic role for neutrophils in the premetastatic lung of mice in models of breast cancer. Here we expand on those findings in the context of human breast cancer. We assessed the cytotoxicity of neutrophils from 90 newly diagnosed breast cancer patients, 24 ductal carcinoma in situ patients, 56 metastatic breast cancer patients, and 64 women with no history of cancer. We report that neutrophils from metastatic and newly diagnosed breast cancer patients are significantly more cytotoxic than neutrophils from cancer-free individuals. We hypothesized that tumor-secreted factors ‘prime’ neutrophils to become cytotoxic. To identify these factors we assayed for cytokines in serum from 54 breast cancer patients and 35 cancer-free controls. Tumor necrosis factor (TNFα), MCP-1 (CCL2), and IL1RA significantly correlated with cytotoxicity and directly stimulated neutrophil cytotoxicity ex vivo. RNA-seq analyses found protein kinase C iota (PRKCI) to be over expressed in patient neutrophils relative to neutrophils from cancer-free individuals. PRKCI has been implicated in NADPH oxidase assembly, required for neutrophil-mediated cell cytotoxicity. Treatment of human neutrophils with TNF-induced PRKCI expression and cytotoxicity in samples that had low basal levels of PRKCI expression. To date, this work is the first to demonstrate the cytotoxic role of neutrophils in the peripheral blood of a large cohort of breast cancer patients, and that select cytokines appear to mediate the stimulation of neutrophil cytotoxicity. Further functional studies are necessary to identify clinically relevant means of stimulating neutrophil cytotoxicity as an effective barrier against disease progression and metastasis.

Immunotherapy for the treatment of breast cancer

Decades of research are now leading to therapeutics that target the molecular mechanisms of the cancer-specific immune response. These therapeutics include tumor antigen vaccines, dendritic cell activators, adjuvants that activate innate immunity, adoptive cellular therapy, and checkpoint blockade. The advances in targeted immunotherapy have led to clinical advances in the treatment of solid tumors such as melanoma, prostate cancer, lung cancer, and hematologic malignancies. Preclinical and translational studies suggest that patients with breast cancer may also benefit from augmenting effective immune responses. These results have led to early-phase clinical trials of tumor antigen vaccines, adjuvants, and combinations of checkpoint inhibitor blockade to boost breast cancer-specific immunity in patients. This review focuses on the current and emerging development of cancer immunotherapy for breast cancer.

Modulating the innate immune activity in murine tumor microenvironment by a combination of inducer molecules attached to microparticles

Targeted cancer immunotherapy is challenging due to the cellular diversity and imposed immune tolerance in the tumor microenvironment (TME). A promising route to overcome those drawbacks may be by activating innate immune cells (IIC) in the TME, toward tumor destruction. Studies have shown the ability to "re-educate" pro-tumor-activated IIC toward antitumor responses. The current research aims to stimulate such activation using a combination of innate activators loaded onto microparticles (MP). Four inducers of Toll-like receptors 4 and 7, complement C5a receptor (C5aR) and gamma Fc receptor and their combinations were loaded on MP, and their influence on immune cell activation evaluated. MP stimulation of immune cell activation was tested in vitro and in vivo using a subcutaneous B16-F10 melanoma model induced in C57BL6 mice. Exposure to the TLR4 ligand lipopolysaccharide (LPS) bound to MP-induced acute inflammatory cytokine and chemokine activity in vitro and in vivo, with the elevation of CD45(+) leukocytes in particular GR-1(+) neutrophils and F4/80 macrophages in the TME. Nevertheless, LPS alone on MP was insufficient to significantly delay tumor progression. LPS combined with the C5aR ligand C5a-pep on the same MP resulted in a similar inflammation activation pattern. However, interleukin-10 levels were lower, and tumor growth was significantly delayed. Mixtures of these two ligands on separate MP did not yield the same cytokine activation pattern, demonstrating the importance of the cells' dual activation. The results suggest that combining inducers of distinct innate immune activation pathways holds promise for successful redirection of TME-residing IIC toward anti-tumoral activation.

Targeting breast cancer-associated fibroblasts to improve anti-cancer therapy

In recent years, mass spectrometry-based proteomics has undergone significant development steps which may be divided into an exploratory phase, a consolidation phase and an application phase. We are in a stage now where we are able to apply mass spectrometric technologies to answer complex and clinically relevant questions. This is demonstrated here with respect to a current hot topic, namely the consideration of the cancer-supporting microenvironment as a target of new and more efficient anti-cancer therapy. Actually, the relevance of micro environmental stromal cells to tumor initiation and promotion has been clearly recognized. However, the individual kind and degree of stroma-derived tumor promotion can so far hardly be determined in patients, and hardly any therapeutic option exists to dismantle the cancer cells of the stroma-derived support. Quite remarkably, the response of stromal cells to standard chemotherapeutics is also rather unknown. In this Perspective, experimental strategies how to address such issues are outlined in detail. Different cell systems are presented as powerful models which allow identifying relevant marker molecules. Targeted proteomics is presented as method of choice for both, drug screening in vitro as well as monitoring drug responses in patients. By this means, a way of classifying different functional tumor promoting mechanisms, evaluating how current treatment strategies may affect cancer-associated fibroblasts, identifying effective drugs targeting these cancer-associated cells and, may be most importantly, demonstrating how combined therapeutic strategies may improve the efficiency of anti-cancer treatments are indicated.

Somatic mutations in leukocytes infiltrating primary breast cancers

Background:

Malignant transformation requires the interaction of cancer cells with their microenvironment, including infiltrating leukocytes. However, somatic mutational studies have focused on alterations in cancer cells, assuming that the microenvironment is genetically normal. Because we hypothesized that this might not be a valid assumption, we performed exome sequencing and targeted sequencing to investigate for the presence of pathogenic mutations in tumor-associated leukocytes in breast cancers.

Methods:

We used targeted sequencing and exome sequencing to evaluate the presence of mutations in sorted tumor-infiltrating CD45-positive cells from primary untreated breast cancers. We used high-depth sequencing to determine the presence/absence of the mutations we identified in breast cancer-infiltrating leukocytes in purified tumor cells and in circulating blood cells.

Results:

Capture-based sequencing of 15 paired tumor-infiltrating leukocytes and matched germline DNA identified variants in known cancer genes in all 15 primary breast cancer patients in our cohort. We validated the presence of mutations identified by targeted sequencing in infiltrating leukocytes through orthogonal exome sequencing. Ten patients harbored alterations previously reported as somatically acquired variants, including in known leukemia genes (DNTM3A, TET2, and BCOR). One of the mutations observed in the tumor-infiltrating leukocytes was also detected in the circulating leukocytes of the same patients at a lower allele frequency than observed in the tumor-infiltrating cells.

Conclusions:

Here we show that somatic mutations, including mutations in known cancer genes, are present in the leukocytes infiltrating a subset of primary breast cancers. This observation allows for the possibility that the cancer cells interact with mutant infiltrating leukocytes, which has many potential clinical implications.