Immunotherapy for triple-negative breast cancer: Existing challenges and exciting prospects

Platelet/Lymphocyte Ratio Is Superior to Neutrophil/Lymphocyte Ratio as a Predictor of Chemotherapy Response and Disease-free Survival in Luminal B-like (HER2-) Breast Cancer

BACKGROUND

The neutrophil/lymphocyte ratio (NLR) and platelet/lymphocyte ratio (PLR) have been associated with the prognosis in breast cancer (BC). The relationship of the NLR and PLR with chemotherapy sensitivity and prognosis in luminal B-like (human epidermal growth factor receptor 2-negative [HER2^-]) BC are not well studied.

PATIENTS AND METHODS

The clinical data from 980 patients with luminal B-like (HER2^-) BC from June 2012 to June 2016 were collected. The differences among the variables were calculated using the χ² test. The associations among the clinicopathologic factors, pretreatment NLR, pretreatment PLR, and disease-free survival (DFS) were analyzed using Kaplan-Meier curves and Cox analyses.

RESULTS

The median follow-up was 37 months (range, 5-77 months). For the 480 patients who had received neoadjuvant chemotherapy, low pretreatment PLR values were associated with higher pathologic complete response (pCR) rates compared with the high PLR group (15.8% for low vs. 9.2% for high PLR group; P = .027). Multivariate analyses showed that larger tumors, a greater number of lymph nodes involved, a high Ki-67 score, and a high PLR were independent prognostic factors of worse outcomes for the patients with luminal B-like (HER2^-) BC. The risk of metastasis and/or recurrence was greater for the high PLR group than for the low PLR group (hazard ratio, 1.576; 95% confidence interval, 1.039-2.390; P = .032). The pretreatment NLR showed no such associations among this cohort of patients.

CONCLUSIONS

The results of the present study have shown that the pretreatment PLR is superior to the NLR as a predictor of pCR and DFS outcomes in patients with luminal B-like (HER2^-) BC. A low pretreatment PLR was associated with higher pCR rates after neoadjuvant chemotherapy and was an independent predictive factor for better DFS outcomes among patients with luminal B-like (HER2^-) BC.

Resveratrol targets PD-L1 glycosylation and dimerization to enhance antitumor T-cell immunity

New strategies to block the immune evasion activity of programmed death ligand-1 (PD-L1) are urgently needed. When exploring the PD-L1-targeted effects of mechanistically diverse metabolism-targeting drugs, exposure to the dietary polyphenol resveratrol (RSV) revealed its differential capacity to generate a distinct PD-L1 electrophoretic migration pattern. Using biochemical assays, computer-aided docking/molecular dynamics simulations, and fluorescence microscopy, we found that RSV can operate as a direct inhibitor of glyco-PD-L1-processing enzymes (α-glucosidase/α-mannosidase) that modulate N-linked glycan decoration of PD-L1, thereby promoting the endoplasmic reticulum retention of a mannose-rich, abnormally glycosylated form of PD-L1. RSV was also predicted to interact with the inner surface of PD-L1 involved in the interaction with PD-1, almost perfectly occupying the target space of the small compound BMS-202 that binds to and induces dimerization of PD-L1. The ability of RSV to directly target PD-L1 interferes with its stability and trafficking, ultimately impeding its targeting to the cancer cell plasma membrane. Impedance-based real-time cell analysis (xCELLigence) showed that cytotoxic T-lymphocyte activity was notably exacerbated when cancer cells were previously exposed to RSV. This unforeseen immunomodulating mechanism of RSV might illuminate new approaches to restore T-cell function by targeting the PD-1/PD-L1 immunologic checkpoint with natural polyphenols.

Expression of glucose-regulated protein 78 as prognostic biomarkers for triple-negative breast cancer

INTRODUCTION

Glucose-regulated protein78(GRP78) is a stress - induced endoplasmic reticulum chaperone protein. it is closely related to the occurrence, development, proliferation, differentiation and drug resistance of breast cancer. However, the association and clinicopathological features between GRP78 and triple negative breast cancer (TNBC) remain to be studied.

MATERIAL AND METHODS

Clinical and pathological characteristics and overall survival were analysed retrospectively in 179 surgically resected TNBC patients. GRP78 was detected by immunohistochemistry (IHC) using breast cancer tissue microarrays (TMAs), and the association between GRP78 levels and clinicopathological factors and prognosis was analyzed. Furthermore, GRP78 expression in human TNBC and NTNBC cell lines was detected by Western blot and qRT-PCR. After Si-GRP78 knocked-down GRP78 in MDA-MB-231 and BT549 cell lines, cell proliferation was detected using Cell Counting Kit-8 (CCK-8) and cell colony formation was detected by crystal violet staining, respectively.

RESULTS

GRP78 was expressed in triple negative breast cancer (TNBC). GRP78 expression was significantly associated with invasive, distant metastasis and proliferation of TNBC (P<0.05). In addition, patients with positive GRP78 expression had shorter overall survival (OS) and disease-free survival (DFS). And the high expression of GRP78 was significantly associated with disease-free survival (DFS) in patients with TNBC (P<0.001).

CONCLUSIONS

These findings improve our understanding of the expression pattern of GRP78 in TNBC and clarify the role of GRP78 as promising prognostic biomarkers for triple-negative breast cancer.

Recent advances in nanotheranostics for triple negative breast cancer treatment

Triple-negative breast cancer (TNBC) is the most complex and aggressive type of breast cancer encountered world widely in women. Absence of hormonal receptors on breast cancer cells necessitates the chemotherapy as the only treatment regime. High propensity to metastasize and relapse in addition to poor prognosis and survival motivated the oncologist, nano-medical scientist to develop novel and efficient nanotherapies to solve such a big TNBC challenge. Recently, the focus for enhanced availability, targeted cellular uptake with minimal toxicity is achieved by nano-carriers. These smart nano-carriers carrying all the necessary arsenals (drugs, tracking probe, and ligand) designed in such a way that specifically targets the TNBC cells at site. Articulating the targeted delivery system with multifunctional molecules for high specificity, tracking, diagnosis, and treatment emerged as theranostic approach. In this review, in addition to classical treatment modalities, recent advances in nanotheranostics for early and effective diagnostic and treatment is discussed. This review highlighted the recently FDA approved immunotherapy and all the ongoing clinical trials for TNBC, in addition to nanoparticle assisted immunotherapy. Futuristic but realistic advancements in artificial intelligence (AI) and machine learning not only improve early diagnosis but also assist clinicians for their workup in TNBC. The novel concept of Nanoparticles induced endothelial leakiness (NanoEL) as a way of tumor invasion is also discussed in addition to classical EPR effect. This review intends to provide basic insight and understanding of the novel nano-therapeutic modalities in TNBC diagnosis and treatment and to sensitize the readers for continue designing the novel nanomedicine. This is the first time that designing nanoparticles with stoichiometric definable number of antibodies per nanoparticle now represents the next level of precision by design in nanomedicine.

The emerging use of immune checkpoint blockade in the adjuvant setting for solid tumors: a review

The use of immune checkpoint inhibitors has been approved in the advanced and metastatic setting for many types of solid tumors. Nonetheless, their role in the adjuvant setting is limited to the treatment of surgically resected melanoma. Ipilimumab was the first immune checkpoint inhibitor approved for this indication, followed by nivolumab and pembrolizumab. Many ongoing trials are evaluating these molecules in the postoperative setting, alone or in combination with other therapies. Preliminary results are promising regarding the treatment of other cutaneous tumors, lung cancers, head and neck squamous cell carcinomas, bladder cancer and renal cell carcinomas. Some data assessing their use for the adjuvant treatment of esophageal, colorectal, ovarian cancer and other solid tumors are similarly emerging.

Targeting tumor phenotypic plasticity and metabolic remodeling in adaptive cross-drug tolerance

Metastable phenotypic state transitions in cancer cells can lead to the development of transient adaptive resistance or tolerance to chemotherapy. Here, we report that the acquisition of a phenotype marked by increased abundance of CD44 (CD44^Hi) by breast cancer cells as a tolerance response to routinely used cytotoxic drugs, such as taxanes, activated a metabolic switch that conferred tolerance against unrelated standard-of-care chemotherapeutic agents, such as anthracyclines. We characterized the sequence of molecular events that connected the induced CD44^Hi phenotype to increased activity of both the glycolytic and oxidative pathways and glucose flux through the pentose phosphate pathway (PPP). When given in a specific order, a combination of taxanes, anthracyclines, and inhibitors of glucose-6-phosphate dehydrogenase (G6PD), an enzyme involved in glucose metabolism, improved survival in mouse models of breast cancer. The same sequence of the three-drug combination reduced the viability of patient breast tumor samples in an explant system. Our findings highlight a convergence between phenotypic and metabolic state transitions that confers a survival advantage to cancer cells against clinically used drug combinations. Pharmacologically targeting this convergence could overcome cross-drug tolerance and could emerge as a new paradigm in the treatment of cancer.

Oncogenic lncRNA downregulates cancer cell antigen presentation and intrinsic tumor suppression

The mechanisms through which tumor cells genetically lose antigenicity and evade immune checkpoints remain largely elusive. Here, we report that tissue-specific expression of the human long-noncoding RNA LINK-A in mouse mammary glands initiated metastatic mammary gland tumors, which phenotypically resembled human triple-negative breast cancer (TNBC). LINK-A expression facilitated crosstalk between phosphatidylinositol-(3,4,5)-trisphosphate and inhibitory G-protein–coupled receptor (GPCR) pathways, attenuating protein kinase A (PKA)-mediated phosphorylation of the E3 ubiquitin ligase TRIM71. Consequently, LINK-A expression enhanced K48–polyubiquitination-mediated degradation of the antigen peptide-loading complex (PLC) and intrinsic tumor suppressors Rb and p53. Treatment with LINK-A-locked nucleic acids or GPCR antagonists stabilized the PLC components, Rb, and p53, and sensitized mammary gland tumors to immune checkpoint blockers (ICBs). Importantly, PD-1 blockade-resistant TNBC patients exhibited elevated LINK-A levels and downregulated PLC components. Hence, we demonstrated lncRNA-dependent downregulation of antigenicity and intrinsic tumor suppression, which may provide the basis for developing a therapeutic regimen of combinational immunotherapy and effective early prevention for TNBCs.

Knockdown of lncRNA-HOTAIR downregulates the drug-resistance of breast cancer cells to doxorubicin via the PI3K/AKT/mTOR signaling pathway

The resistance to chemotherapeutic drugs is a critical feature of breast cancer recurrence and metastasis. Long non-coding RNAs (LncRNAs) serve key roles in tumor drug resistance. LncRNA-HOX transcript antisense RNA (HOTAIR) has been reported to be overexpressed in certain types of cancer and may be closely associated with tumor resistance. The current study aimed to investigate the role of lncRNA-HOTAIR in the regulation of breast cancer resistance to doxorubicin (DOX). A breast cancer cell line (MCF-7) and DOX-resistant breast cancer cell line (DOXR-MCF-7) were utilized in the current study. DOXR-MCF-7 cells were transfected with lncRNA-HOTAIR small interfering RNA (siRNA) and control siRNA. Subsequently, MTT and colony formation assays were performed to assess cell proliferation. Cell apoptosis was also evaluated via flow cytometry. In addition, western blotting and reverse transcription-quantitative polymerase chain reaction were performed to detect the expression of caspase-3, B-cell lymphoma 2, Bcl-2-associated X protein, phosphoinositide 3-kinase (PI3K), protein kinase B (AKT) and mechanistic target of rapamycin (mTOR), and the phosphorylation of PI3K, AKT, and mTOR. The data indicated that lncRNA-HOTAIR silencing decreased cell proliferation and increased apoptosis in MCF-7 and DOXR MCF-7 cells. Furthermore, lncRNA-HOTAIR silencing significantly decreased the phosphorylation of PI3K, AKT and mTOR, indicating that the knockdown of lncRNA-HOTAIR effectively attenuates the resistance of breast cancer cells to DOX by inhibiting the PI3K/AKT/mTOR pathway. In summary, the present study indicated that the knockdown of lncRNA-HOTAIR weakened the resistance of breast cancer cells to DOX via PI3K/AKT/mTOR signaling, suggesting that lncRNA-HOTAIR may be a novel intervention target to reverse DOX-resistance in breast cancer.

Novel insights into the role of aptamers in the fight against cancer

PURPOSE

Aptamers are a class of single-stranded nucleic acid (DNA or RNA) oligonucleotides that are screened in vitro by a technique called systematic evolution of ligands by exponential enrichment (SELEX). They have stable three-dimensional structures that can bind to various targets with high affinity and specificity. Due to distinct properties such as easy synthesis, high stability, small size, low toxicity and immunogenicity, they have been largely studied as anticancer agents/tools. Consequently, aptamers are starting to play important roles in disease prevention, diagnosis and therapy. This review focuses on studies that evaluated the effect of aptamers on various aspects of cancer therapy. It also provides novel and unique insights into the role of aptamers on the fight against cancer.

METHODS

We reviewed literatures about the role of aptamers against cancer from PUBMED databases in this article.

RESULTS

Here, we summarized the role of aptamers on the fight against cancer in a unique point of view. Meanwhile, we presented novel ideas such as aptamer-pool-drug conjugates for the treatment of refractory cancers.

CONCLUSIONS

Aptamers and antibodies should form a "coalition" against cancers to maximize their advantages and minimize disadvantages.

Recent therapeutic trends and promising targets in triple negative breast cancer

Breast cancer accounts for 25% of all types of cancer in women, and triple negative breast cancer (TNBC) comprises around 15~20% of breast cancers. Conventional chemotherapy and radiation are the primary systemic therapeutic strategies; no other FDA-approved targeted therapies are yet available as for TNBC. TNBC is generally characterized by a poor prognosis and high rates of proliferation and metastases. Due to these aggressive features and lack of targeted therapies, numerous attempts have been made to discover viable molecular targets for TNBC. Massive cohort studies, clinical trials, and in-depth analyses have revealed diverse molecular alterations in TNBC; however, controversy exists as to whether many of these changes are beneficial or detrimental in caner progression. Here we review the complicated tumorigenic processes and discuss critical findings and therapeutic trends in TNBC with a focus on promising therapeutic approaches, the clinical trials currently underway, and potent experimental compounds under preclinical and evaluation.

Immunological therapy: A novel thriving area for triple-negative breast cancer treatment

Triple-negative breast cancer (TNBC) refers to cancers that are low in expression of the estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2). TNBC tends to behave more aggressively than other types of breast cancer. Unlike other breast cancer subtypes (ie, ER-positive, HER2-positive subtypes), there are no approved targeted treatments available, other than the administration of chemotherapy. Immunotherapy is a new kind of treatment approach for TNBC when compared with the surgical treatment, chemotherapy, endocrine therapy, and molecular targeting therapy. The present article reviews the research progresses of immunotherapy for TNBC in recent years. The full text structure covers molecular classification of TNBC, active immunotherapy of TNBC, passive immunotherapy of TNBC, oncolytic immunotherapy and the prospect of immunotherapy for TNBC.

In silico design of a triple-negative breast cancer vaccine by targeting cancer testis antigens

Introduction: Triple-negative breast cancer (TNBC) is an important subtype of breast cancer, which occurs in the absence of estrogen, progesterone and HER-2 receptors. According to the recent studies, TNBC may be a cancer testis antigen (CTA)-positive tumor, indicating that the CTA-based cancer vaccine can be a treatment option for the patients bearing such tumors. Of these antigens (Ags), the MAGE-A family and NY-ESO-1 as the most immunogenic CTAs are the potentially relevant targets for the development of an immunotherapeutic way of the breast cancer treatment. Methods: In the present study, immunoinformatics approach was used to design a multi-epitope peptide vaccine to combat the TNBC. The vaccine peptide was constructed by the fusion of three crucial components, including the CD8+ cytotoxic T lymphocytes (CTLs) epitopes, helper epitopes and adjuvant. The epitopes were predicted from the MAGE-A and NY-ESO-1 Ags. In addition, the granulocyte-macrophage-colony-stimulating factor (GM-CSF) was used as an adjuvant to promote the CD4+ T cells towards the T-helper for more strong induction of CTL responses. The components were conjugated by proper linkers. Results: The vaccine peptide was examined for different physiochemical characteristics to confirm the safety and immunogenic behavior. Furthermore, the 3D-structure of the vaccine peptide was predicted based on the homology modeling approach using the MODELLER v9.17 program. The vaccine structure was also subjected to the molecular dynamics simulation study for structure refinement. The results verified the immunogenicity and safety profile of the constructed vaccine as well as its capability for stimulating both the cellular and humoral immune responses. Conclusion: Based on our in-silico analyses, the proposed vaccine may be considered for the immunotherapy of TNBC.

Targeting invadopodia for blocking breast cancer metastasis

Dissemination of cancer cells from the primary tumor and their spread to distant sites of the body is the leading cause of mortality in metastatic cancer patients. Metastatic cancer cells invade surrounding tissues and blood vessels by forming F-actin-rich protrusions known as invadopodia, which degrade the extracellular matrix and enable invasion of tumor cells through it. Invadopodia have now been observed in vivo, and recent evidence demonstrates direct molecular links between assembly of invadopodia and cancer metastasis in both mouse models and in human patients. While significant progress has been achieved in the last decade in understanding the molecular mechanisms and signaling pathways regulating invadopodia formation and function, the application of this knowledge to development of prognostic and therapeutic approaches for cancer metastasis has not been discussed before. Here, we provide a detailed overview of current prognostic markers and tests for cancer metastasis and discuss their advantages, disadvantages, and their predicted efficiency. Using bioinformatic patient database analysis, we demonstrate, for the first time, a significant correlation between invadopodia-associated genes to breast cancer metastasis, suggesting that invadopodia could be used as both a prognostic marker and as a therapeutic target for blocking cancer metastasis. We include here a novel network interaction map of invadopodia-associated proteins with currently available inhibitors, demonstrating a central role for the recently identified EGFR-Pyk2-Src-Arg-cortactin invadopodial pathway, to which re-purposing of existent inhibitors could be used to block breast cancer metastasis. We then present an updated overview of current cancer-related clinical trials, demonstrating the negligible number of trials focusing on cancer metastasis. We also discuss the difficulties and complexity of performing cancer metastasis clinical trials, and the possible development of anti-metastasis drug resistance when using a prolonged preventive treatment with invadopodia inhibitors. This review presents a new perspective on invadopodia-mediated tumor invasiveness and may lead to the development of novel prognostic and therapeutic approaches for cancer metastasis.

Chemoresistance‑related long non‑coding RNA expression profiles in human breast cancer cells

Breast cancer is the most commonly diagnosed cancer and the leading cause of cancer death in females worldwide. Chemoresistance has been a major reason for the drug therapy failure. The present study performed a microarray analysis between MCF-7 and MCF-7/adriamycin (ADR) cells, and intended to identify long non-coding (lnc)RNA expression character in drug resistant breast cancer cells. MCF-7/ADR cells were induced from MCF-7 cells via pulse-selection with doxorubicin for 4 weeks, and the resistance to doxorubicin of ADR cells was confirmed by MTT assay. Microarray analysis was performed between MCF-7 and MCF-7/ADR cells. Total RNA was extracted from the two cell lines respectively and was transcribed into cDNA. The results of the microarray were verified by reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Gene Ontology (GO) and pathways analysis were conducted to enrich the dysregulated lncRNAs presented in the microarray results. Compared to the MCF-7 cells, 8,892 lncRNAs were differentially expressed in MCF/ADR cells (absolute fold-change >2.0). A total of 32 lncRNAs were selected for RT-qPCR by fold-change filtering, standard Student's t-test, and multiple hypothesis testing. Among the dysregulated lncRNAs, AX747207 was prominent because its associated gene RUNX3 was previously reported to be relative to malignant tumor chemoresistance. GO analysis results also indicated some biological processes and molecular functions linked to chemoresistance. The pathway enrichment results provided some potential pathways associated with chemoresistance. In the present study, the authors intended to identify lncRNA expression character in drug resistant cell line MCF-7/ADR, corresponding to the parental MCF-7 cell line. In addition, the study identified the lncRNA AX747207, and its potential targeted gene RUNX3, may be related to chemoresistance in breast cancer. These results may new insights into exploring the mechanisms of chemoresistance in breast cancer.

Breast cancer family history and allele-specific DNA methylation in the legacy girls study

Family history, a well-established risk factor for breast cancer, can have both genetic and environmental contributions. Shared environment in families as well as epigenetic changes that also may be influenced by shared genetics and environment may also explain familial clustering of cancers. Epigenetic regulation, such as DNA methylation, can change the activity of a DNA segment without a change in the sequence; environmental exposures experienced across the life course can induce such changes. However, genetic-epigenetic interactions, detected as methylation quantitative trait loci (mQTLs; a.k.a. meQTLs) and haplotype-dependent allele-specific methylation (hap-ASM), can also contribute to inter-individual differences in DNA methylation patterns. To identify differentially methylated regions (DMRs) associated with breast cancer susceptibility, we examined differences in white blood cell DNA methylation in 29 candidate genes in 426 girls (ages 6-13 years) from the LEGACY Girls Study, 239 with and 187 without a breast cancer family history (BCFH). We measured methylation by targeted massively parallel bisulfite sequencing (bis-seq) and observed BCFH DMRs in two genes: ESR1 (Δ4.9%, P = 0.003) and SEC16B (Δ3.6%, P = 0.026), each of which has been previously implicated in breast cancer susceptibility and pubertal development. These DMRs showed high inter-individual variability in methylation, suggesting the presence of mQTLs/hap-ASM. Using single nucleotide polymorphisms data in the bis-seq amplicon, we found strong hap-ASM in SEC16B (with allele specific-differences ranging from 42% to 74%). These findings suggest that differential methylation in genes relevant to breast cancer susceptibility may be present early in life, and that inherited genetic factors underlie some of these epigenetic differences.

Targeting Tumor Metabolism: A New Challenge to Improve Immunotherapy

Currently, a marked number of clinical trials on cancer treatment have revealed the success of immunomodulatory therapies based on immune checkpoint inhibitors that activate tumor-specific T cells. However, the therapeutic efficacy of cancer immunotherapies is only restricted to a small fraction of patients. A deeper understanding of key mechanisms generating an immunosuppressive tumor microenvironment (TME) remains a major challenge for more effective antitumor immunity. There is a growing evidence that the TME supports inappropriate metabolic reprogramming that dampens T cell function, and therefore impacts the antitumor immune response and tumor progression. Notably, the immunosuppressive TME is characterized by a lack of crucial carbon sources critical for T cell function and increased inhibitory signals. Here, we summarize the basics of intrinsic and extrinsic metabolic remodeling and metabolic checkpoints underlying the competition between cancer and infiltrating immune cells for nutrients and metabolites. Intriguingly, the upregulation of tumor programmed death-L1 and cytotoxic T lymphocyte-associated antigen 4 alters the metabolic programme of T cells and drives their exhaustion. In this context, targeting both tumor and T cell metabolism can beneficially enhance or temper immunity in an inhospitable microenvironment and markedly improve the success of immunotherapies.