Taxanes enhance trastuzumab-mediated ADCC on tumor cells through NKG2D-mediated NK cell recognition

NK cell immunopotentiators-loaded nanoliposomes enhance ADCC effect for targeted therapy against HER2-positive breast cancer

Trastuzumab serves as a cornerstone of first-line therapy for HER2-positive (HER2+) breast cancer; however, a significant challenge arises due to the emergence of resistance within approximately one year of commencement of treatment, particularly in advanced cases with metastatic disease where its efficacy is limited. Our investigation into the tumor tissue from HER2+ breast cancer patients, employing single-cell sequencing and bioinformatics analysis, has elucidated a crucial mechanism underlying the reduced responsiveness of tumors to trastuzumab: the diminished infiltration and activity of natural killer (NK) cells within the tumor microenvironment (TME). To counteract this impediment, we meticulously selected two potent immune-modulating peptides TKD and IP-10p, which are known to recruit and enhance the activity of NK cells. Through in vitro experiments, we substantiated that bolstering the tumor infiltration and activity of NK cells can lead to an enhanced antibody-dependent cell-mediated cytotoxicity (ADCC) effect, thereby amplifying the anti-tumor activity of trastuzumab. Building upon this foundational discovery, we further designed HER2-targeted pH-sensitive nanoliposomes to encapsulate TKD and IP-10p peptides. The novel designed nanoliposomes were strategically employed in conjunction with NK cell supplement therapy within a HER2+ breast cancer model undergoing trastuzumab treatment, yielding a striking anti-tumor response and indicating that the combination strategy effectively reinvigorated the anti-tumor immune response. In essence, this study not only underscores a critical link between the diminished ADCC effect mediated by trastuzumab and the development of resistance in HER2+ breast cancer but also demonstrates leveraging HER2-targeted nanoliposomes to deliver NK cell immunopotentiators can significantly enhance the functional activity of NK cells and their infiltration within the TME, culminating in improved antitumor efficacy of trastuzumab through the augmentation of the ADCC effect.

Tinostamustine (EDO-S101), an Alkylating Deacetylase Inhibitor, Enhances the Efficacy of Daratumumab in Multiple Myeloma by Upregulation of CD38 and NKG2D Ligands

Multiple myeloma is a malignancy characterized by the accumulation of malignant plasma cells in bone marrow and the production of monoclonal immunoglobulin. A hallmark of cancer is the evasion of immune surveillance. Histone deacetylase inhibitors have been shown to promote the expression of silenced molecules and hold potential to increase the anti-MM efficacy of immunotherapy. The aim of the present work was to assess the potential effect of tinostamustine (EDO-S101), a first-in-class alkylating deacetylase inhibitor, in combination with daratumumab, an anti-CD38 monoclonal antibody (mAb), through different preclinical studies. Tinostamustine increases CD38 expression in myeloma cell lines, an effect that occurs in parallel with an increment in CD38 histone H3 acetylation levels. Also, the expression of MICA and MICB, ligands for the NK cell activating receptor NKG2D, augments after tinostamustine treatment in myeloma cell lines and primary myeloma cells. Pretreatment of myeloma cell lines with tinostamustine increased the sensitivity of these cells to daratumumab through its different cytotoxic mechanisms, and the combination of these two drugs showed a higher anti-myeloma effect than individual treatments in ex vivo cultures of myeloma patients' samples. In vivo data confirmed that tinostamustine pretreatment followed by daratumumab administration significantly delayed tumor growth and improved the survival of mice compared to individual treatments. In summary, our results suggest that tinostamustine could be a potential candidate to improve the efficacy of anti-CD38 mAbs.

The cellular composition of the tumor microenvironment is an important marker for predicting therapeutic efficacy in breast cancer

At present, the incidence rate of breast cancer ranks first among new-onset malignant tumors in women. The tumor microenvironment is a hot topic in tumor research. There are abundant cells in the tumor microenvironment that play a protumor or antitumor role in breast cancer. During the treatment of breast cancer, different cells have different influences on the therapeutic response. And after treatment, the cellular composition in the tumor microenvironment will change too. In this review, we summarize the interactions between different cell compositions (such as immune cells, fibroblasts, endothelial cells, and adipocytes) in the tumor microenvironment and the treatment mechanism of breast cancer. We believe that detecting the cellular composition of the tumor microenvironment is able to predict the therapeutic efficacy of treatments for breast cancer and benefit to combination administration of breast cancer.

The nexus of natural killer cells and melanoma tumor microenvironment: crosstalk, chemotherapeutic potential, and innovative NK cell-based therapeutic strategies

The metastasis of melanoma cells to regional lymph nodes and distant sites is an important contributor to cancer-related morbidity and mortality among patients with melanoma. This intricate process entails dynamic interactions involving tumor cells, cellular constituents, and non-cellular elements within the microenvironment. Moreover, both microenvironmental and systemic factors regulate the metastatic progression. Central to immunosurveillance for tumor cells are natural killer (NK) cells, prominent effectors of the innate immune system with potent antitumor and antimetastatic capabilities. Recognizing their pivotal role, contemporary immunotherapeutic strategies are actively integrating NK cells to combat metastatic tumors. Thus, a meticulous exploration of the interplay between metastatic melanoma and NK cells along the metastatic cascade is important. Given the critical involvement of NK cells within the melanoma tumor microenvironment, this comprehensive review illuminates the intricate relationship between components of the melanoma tumor microenvironment and NK cells, delineating their multifaceted roles. By shedding light on these critical aspects, this review advocates for a deeper understanding of NK cell dynamics within the melanoma context, driving forward transformative strategies to combat this cancer.

HER-2 Expression in Colorectal Cancer and Its Correlation with Immune Cell Infiltration

BACKGROUND

This study aimed to investigate the effect of increased HER-2 expression on tumor-infiltrating lymphocytes (TILs) and determine its impact on the prognosis of colorectal cancer (CRC) patients; Methods: HER-2, CD4, CD8, CD19, LY6G, CD56, CD68, CD11b, and EpCam expression in CRC tissues and adjacent paracancerous tissues were assessed using multiplex fluorescence immunohistochemical staining. The correlation between HER-2 expression and the number of TILs in CRC tissues was analyzed. Kaplan-Meier and Cox proportional hazards models were used to analyze survival outcomes; Results: The expression of HER-2 in tumor tissues was higher than that in paracancerous tissues (1.31 ± 0.45 vs. 0.86 ± 0.20, p < 0.05). Additionally, there was an increase in the numbers of CD4+, CD8+, CD19+, and CD68+ cells in CRC tissues (14.11 ± 1.10 vs. 3.40 ± 0.18, p < 0.005; 0.16 ± 0.12 vs. 0.04 ± 0.04, p < 0.005; 0.71 ± 0.46 vs. 0.25 ± 0.13, p < 0.0005; 0.27 ± 0.24 vs. 0.03 ± 0.11, p < 0.05). An increase in HER-2 expression was positively correlated with an increase in CD4, CD8, and CD19 (p < 0.0001). In HER-2-positive CRC tissues, CD68 expression was increased (0.80 ± 0.55 vs. 0.25 ± 0.22, p < 0.05). In HER-2-upregulated CRC tissues, CD4, CD8, CD19, CD68, CD11b, Ly6G, and CD56 expressions were elevated (0.70 ± 0.37 vs. 0.32 ± 0.17, p = 0.03; 0.22 ± 0.13 vs. 0.09 ± 0.06, p = 0.03; 0.31 ± 0.19 vs. 0.12 ± 0.08, p = 0.02; 1.05 ± 0.62 vs. 0.43 ± 0.21, p < 0.01; 1.34 ± 0.81 vs. 0.53 ± 0.23, p < 0.01; 0.50 ± 0.31 vs. 0.19 ± 0.10, p < 0.01; 1.26 ± 0.74 vs. 0.52 ± 0.24, p < 0.01). Furthermore, increased HER-2 expression was an independent risk factor for recurrence-free survival (RFS) in patients (p < 0.01, HR = 3.421); Conclusions: The increased expression of HER-2 and its relationship with immune cells will provide new insights for immunotherapy in CRC patients.

Alterations in immune cell phenotype and cytotoxic capacity in HER2+ breast cancer patients receiving HER2-targeted neo-adjuvant therapy

BACKGROUND

The phase II neo-adjuvant clinical trial ICORG10-05 (NCT01485926) compared chemotherapy in combination with trastuzumab, lapatinib or both in patients with HER2+ breast cancer. We studied circulating immune cells looking for alterations in phenotype, genotype and cytotoxic capacity (direct and antibody-dependent cell-mediated cytotoxicity (ADCC)) in the context of treatment response.

METHODS

Peripheral blood mononuclear cells (PBMCs) were isolated from pre- (n = 41) and post- (n = 25) neo-adjuvant treatment blood samples. Direct/trastuzumab-ADCC cytotoxicity of patient-derived PBMCs against K562/SKBR3 cell lines was determined ex vivo. Pembrolizumab was interrogated in 21 pre-treatment PBMC ADCC assays. Thirty-nine pre-treatment and 21 post-treatment PBMC samples were immunophenotyped. Fc receptor genotype, tumour infiltrating lymphocyte (TIL) levels and oestrogen receptor (ER) status were quantified.

RESULTS

Treatment attenuated the cytotoxicity/ADCC of PBMCs. CD3+/CD4+/CD8+ T cells increased following therapy, while CD56+ NK cells/CD14+ monocytes/CD19+ B cells decreased with significant post-treatment immune cell changes confined to patients with residual disease. Pembrolizumab-augmented ex vivo PBMC ADCC activity was associated with residual disease, but not pathological complete response. Pembrolizumab-responsive PBMCs were associated with lower baseline TIL levels and ER+ tumours.

CONCLUSIONS

PBMCs display altered phenotype and function following completion of neo-adjuvant treatment. Anti-PD-1-responsive PBMCs in ex vivo ADCC assays may be a biomarker of treatment response.

The interactions of docetaxel with tumor microenvironment

There are several interactions within the tumor microenvironment (TME) that affect the response of cancer cells to therapy. There are also a large number of cells and secretions in TME that increase resistance to therapy. Following the release of immunosuppressive, pro-angiogenic, and metastatic molecules by certain cells such as tumor-associated macrophages (TAMs), cancer-associated fibroblasts (CAFs), and cancer cells, immune evasion, angiogenesis, and metastasis may be induced. However, natural killer (NK) cells and cytotoxic CD8 + T lymphocytes (CTLs) can responsively release anticancer molecules. In addition, anticancer drugs can modulate these cells and their interactions in favor of either cancer resistance or therapy. Docetaxel belongs to taxanes, a class of anti-tumor drugs, which acts through the polymerization of tubulin and the induction of cell cycle arrest. Also, it has been revealed that taxanes including docetaxel affect cancer cells and the other cells within TME through some other mechanisms such as modulation of immune system responses, angiogenesis, and metastasis. In this paper, we explain the basic mechanisms of docetaxel interactions with malignant cells. Besides, we review the diverse effects of docetaxel on TME and cancer cells in consequence. Lastly, the modulatory effects of docetaxel alone or in conjunction with other anticancer agents on anti-tumor immunity, cancer cell resistance, angiogenesis, and metastasis will be discussed.

Receptors of immune cells mediates recognition for tumors

Over the last few decades, the immune system has been steered toward eradication of cancer cells with the help of cancer immunotherapy. T cells, B cells, monocytes/macrophages, dendritic cells, T-reg cells, and natural killer (NK) cells are some of the numerous immune cell types that play a significant part in cancer cell detection and reduction of inflammation, and the antitumor response. Briefly stated, chimeric antigen receptors, adoptive transfer and immune checkpoint modulators are currently the subjects of research focus for successful immunotherapy-based treatments for a variety of cancers. This chapter discusses ongoing investigations on the mechanisms and recent developments by which receptors of immune cells especially that of lymphocytes and monocytes/macrophages regulate the detection of immune system leading to malignancies. We will also be looking into the treatment strategies based on these mechanisms.

Targeting CD70 in combination with chemotherapy to enhance the anti-tumor immune effects in non-small cell lung cancer

Despite the recent emergence of immune checkpoint inhibitors, clinical outcomes of metastatic NSCLC patients remain poor, pointing out the unmet need to develop novel therapies to enhance the anti-tumor immune response in NSCLC. In this regard, aberrant expression of the immune checkpoint molecule CD70 has been reported on many cancer types, including NSCLC. In this study, the cytotoxic and immune stimulatory potential of an antibody-based anti-CD70 (aCD70) therapy was explored as single agent and in combination with docetaxel and cisplatin in NSCLC in vitro and in vivo. Anti-CD70 therapy resulted in NK-mediated killing of NSCLC cells and increased production of pro-inflammatory cytokines by NK cells in vitro. The combination of chemotherapy and anti-CD70 therapy further enhanced NSCLC cell killing. Moreover, in vivo findings showed that the sequential treatment of chemo-immunotherapy resulted in a significant improved survival and delayed tumor growth compared to single agents in Lewis Lung carcinoma-bearing mice. The immunogenic potential of the chemotherapeutic regimen was further highlighted by increased numbers of dendritic cells in the tumor-draining lymph nodes in these tumor-bearing mice after treatment. The sequential combination therapy resulted in enhanced intratumoral infiltration of both T and NK cells, as well as an increase in the ratio of CD8+ T cells over Tregs. The superior effect of the sequential combination therapy on survival was further confirmed in a NCI-H1975-bearing humanized IL15-NSG-CD34+ mouse model. These novel preclinical data demonstrate the potential of combining chemotherapy and aCD70 therapy to enhance anti-tumor immune responses in NSCLC patients.

HER2 mRNA Levels, Estrogen Receptor Activity and Susceptibility to Trastuzumab in Primary Breast Cancer

While the results thus far demonstrate the clinical benefit of trastuzumab in breast cancer (BC), some patients do not respond to this drug. HER2 mRNA, alone or combined with other genes/biomarkers, has been proven to be a powerful predictive marker in several studies. Here, we provide evidence of the association between HER2 mRNA levels and the response to anti-HER2 treatment in HER2-positive BC patients treated with adjuvant trastuzumab and show that this association is independent of estrogen receptor (ER) tumor positivity. While HER2 mRNA expression was significantly correlated with HER2 protein levels in ER-negative tumors, no correlation was found in ER-positive tumors, and HER2 protein expression was not associated with relapse risk. Correlation analyses in the ER-positive subset identified ER activity as the pathway inversely associated with HER2 mRNA. Associations between HER2 levels and oncogene addiction, as well as between HER2 activation and trastuzumab sensitivity, were also observed in vitro in HER2-positive BC cell lines. In ER-positive but not ER-negative BC cells, HER2 transcription was increased by reducing ligand-dependent ER activity or inducing ER degradation. Accordingly, HER2 mRNA levels in patients were found to be inversely correlated with blood levels of estradiol, the natural ligand of ER that induces ER activation. Moreover, low estradiol levels were associated with a lower risk of relapse in HER2-positive BC patients treated with adjuvant trastuzumab. Overall, we found that HER2 mRNA levels, but not protein levels, indicate the HER2 dependency of tumor cells and low estrogen-dependent ER activity in HER2-positive tumors.

A systemic review of taxanes and their side effects in metastatic breast cancer

Taxanes-containing chemotherapy constitutes an essential backbone for both early and metastatic breast cancer (mBC). However, the two major taxane drugs—paclitaxel and docetaxel—have distinct safety profiles. In this review, we summarize the safety outcome and management following treatment with both taxanes from selected clinical trials. We utilized PubMed to perform literature search before April 2021. Five phase III randomized controlled trials with reports of individual taxane adverse events (AEs) were included in this review. Grade 3/4 AEs were summarized and discussed extensively. The rates of grade 3/4 neutropenia were higher with docetaxel than with paclitaxel. For non-hematologic grade 3/4 AEs, peripheral neuropathy was more frequent with paclitaxel while fluid retention was more frequent with docetaxel. Compared to paclitaxel, docetaxel had a higher rate of grade 3/4 gastrointestinal AEs. Grade 3/4 myalgia were generally comparable between the two taxanes. Except for neutropenia, the incidence rate of grade 3/4 AEs of taxanes was generally manageable. Peripheral neuropathy was more common with paclitaxel while grade 3/4 neutropenia was more common with docetaxel.

FLOT Versus FLOT/Trastuzumab/Pertuzumab Perioperative Therapy of Human Epidermal Growth Factor Receptor 2-Positive Resectable Esophagogastric Adenocarcinoma: A Randomized Phase II Trial of the AIO EGA Study Group

PURPOSE

High pathologic complete response (pCR) rates and comparably good survival data were seen in a phase II trial combining perioperative fluorouracil, leucovorin, oxaliplatin, and docetaxel (FLOT) chemotherapy with trastuzumab for resectable, esophagogastric adenocarcinoma (EGA). The current trial evaluates the addition of trastuzumab and pertuzumab to FLOT as perioperative treatment for human epidermal growth factor receptor 2-positive resectable EGA.

METHODS

In this multicenter, randomized phase II/III trial, patients with human epidermal growth factor receptor 2-positive, resectable EGA (≥ clinical tumor 2 or clinical nodal-positive) were assigned to four pre- and postoperative cycles of either FLOT alone (arm A) or combined with trastuzumab and pertuzumab, followed by nine cycles of trastuzumab/pertuzumab (arm B). The primary end point for the phase II part was the rate of pCR.

RESULTS

The trial was closed prematurely, without transition into phase III, after results of the JACOB trial were reported. Eighty-one patients were randomly assigned (A: 41/B: 40) during the phase II part. The pCR rate was significantly improved with the trastuzumab/pertuzumab treatment (A: 12%/B: 35%; P = .02). Similarly, the rate of pathologic lymph node negativity was higher with trastuzumab/pertuzumab (A: 39%/B: 68%), whereas the R0 resection rate (A: 90%/B: 93%) and surgical morbidity (A: 43%/B: 44%) were comparable. Moreover, the inhouse mortality was equal in both arms (overall 2.5%). The median disease-free survival was 26 months in arm A and not yet reached in arm B (hazard ratio 0.58; P = .14). After a median follow-up of 22 months, the median overall survival was not yet reached (hazard ratio 0.56; P = .24). Disease-free survival and overall survival rates (95% CI) at 24 months were 54% (38 to 71) and 77% (63 to 90) in arm A and 70% (55 to 85) and 84% (72 to 96) in arm B, respectively. More ≥ grade 3 adverse events were reported with trastuzumab/pertuzumab, especially diarrhea (A: 5%/B: 41%) and leukopenia (A: 13%/B: 23%).

CONCLUSION

The addition of trastuzumab/pertuzumab to perioperative FLOT significantly improved pCR and nodal negativity rates at the price of higher rates of diarrhea and leukopenia.

Clinical trial data and emerging strategies: HER2-positive breast cancer

A deeper insight into tumor biology and HER2 signaling has led to the development of novel anti-HER2 drugs that have significantly improved the prognosis of patients with HER2-positive breast cancer. The breast cancer immune microenvironment has emerged as a potential prognostic factor. Moreover, the host immune system not only seems to play a critical role in the prognosis of HER2-positive breast cancer, but also seems to modulate treatment response to some HER2-targeted agents. Here, we review the latest evidence of the role of immunotherapy in HER2-positive breast cancer and present emerging strategies.

Interest of the Addition of Taxanes to Standard Treatment in First-Line Advanced HER2 Positive Gastroesophageal Adenocarcinoma in Selective Patients

Background

Studies have reported a beneficial role of the addition of trastuzumab to platin-5-FU based chemotherapy in first-line advanced HER2 positive gastroesophageal adenocarcinoma (GEA). However, the effect of taxanes combined with platin-5FU + trastuzumab (PFT) is understudied.

Methods

We performed a retrospective cohort study to evaluate the interest of taxanes among HER2-positive advanced GEA patients treated with PFT. We enrolled HER2-positive advanced GEA patients who underwent treatment between January 2009 to March 2021 in seven hospitals centers in France, treated with PFT alone (S group) or with taxanes + PFT regimen (T group). The primary outcome was progression-free survival (PFS). Also, overall survival (OS), response rate, conversion surgery rate, and safety were evaluated.

Results

Overall, 65 patients received PFT-based therapy, 24 patients in the T group, and 41 patients in the S group. To avoid the selection bias, only those patients presenting an ECOG-PS of 0-1 and synchronous metastasis (21 patients in the T group and 19 patients in the S group) were included for analysis. The median PFS was 9.3 months (95%CI 7.0 to 17.2) in the T group and 5.9 months (95%CI 3.7 to 9.6) in the S group (log-rank p=0.038). Treatment by taxanes was significantly associated with a better PFS in univariate (HR 0.49; 95%CI 0.25 to 0.98, p=0.042) and multivariate Cox regression analysis (HR 0.44; 95%CI 0.21 to 0.94, p=0.033), and IPTW method (HR 0.56; 95% CI 0.34 to 0.91, p=0.019). OS was prolonged (19.0 months (95%CI 7.8 to 45.2) vs 13.0 months (95%CI 5.5 to 14.8), log-rank p=0.033) in favor of the T group. Treatment by taxanes was significantly associated with a better OS in univariate Cox regression analysis (HR 0.49; 95%CI 0.21 to 0.96, p=0.038) and IPTW method (HR 0.49; 95% CI 0.29 to 0.84, p=0.009). The response rate was higher in the T group, with conversion surgery in five patients. No treatment-related death was observed in both groups.

Conclusions

Given the improvement in PFS and OS, the addition of taxanes to standard chemotherapy could be considered as a promising treatment for selected HER2-positive advanced GEA patients, with PS 0-1 and synchronous metastasis (NCT04920747).

Role of Fcγ receptors in HER2-targeted breast cancer therapy

Several therapeutic monoclonal antibodies (mAbs), including those targeting epidermal growth factor receptor, human epidermal growth factor receptor 2 (HER2), and CD20, mediate fragment crystallizable gamma receptor (FcγR)–dependent activities as part of their mechanism of action. These activities include induction of antibody-dependent cellular cytotoxicity (ADCC) and antibody-dependent cellular phagocytosis (ADCP), which are innate immune mechanisms of cancer cell elimination. FcγRs are distinguished by their affinity for the Fc fragment, cell distribution, and type of immune response they induce. Activating FcγRIIIa (CD16A) on natural killer cells plays a crucial role in mediating ADCC, and activating FcγRIIa (CD32A) and FcγRIIIa on macrophages are important for mediating ADCP. Polymorphisms in FcγRIIIa and FcγRIIa generate variants that bind to the Fc portion of antibodies with different affinities. This results in differential FcγR-mediated activities associated with differential therapeutic outcomes across multiple clinical settings, from early stage to metastatic disease, in patients with HER2+ breast cancer treated with the anti-HER2 mAb trastuzumab. Trastuzumab has, nonetheless, revolutionized HER2+ breast cancer treatment, and several HER2-directed mAbs have been developed using Fc glyco-engineering or Fc protein-engineering to enhance FcγR-mediated functions. An example of an approved anti-HER2 Fc-engineered chimeric mAb is margetuximab, which targets the same epitope as trastuzumab, but features five amino acid substitutions in the IgG 1 Fc domain that were deliberately introduced to increase binding to activating FcγRIIIa and decrease binding to inhibitory FcγRIIb (CD32B). Margetuximab enhances Fc-dependent ADCC in vitro more potently than the combination of pertuzumab (another approved mAb directed against an alternate HER2 epitope) and trastuzumab. Margetuximab administration also enhances HER2-specific B cell and T cell–mediated responses ex vivo in samples from patients treated with prior lines of HER2 antibody-based therapies. Stemming from these observations, a worthwhile future goal in the treatment of HER2+ breast cancer is to promote combinatorial approaches that better eradicate HER2+ cancer cells via enhanced immunological mechanisms.

NK Cells in the Tumor Microenvironment as New Potential Players Mediating Chemotherapy Effects in Metastatic Melanoma

Until the last decade, chemotherapy was the standard treatment for metastatic cutaneous melanoma, even with poor results. The introduction of immune checkpoints inhibitors (ICIs) radically changed the outcome, increasing 5-year survival from 5% to 60%. However, there is still a large portion of unresponsive patients that would need further therapies. NK cells are skin-resident innate cytotoxic lymphocytes that recognize and kill virus-infected as well as cancer cells thanks to a balance between inhibitory and activating signals delivered by surface molecules expressed by the target. Since NK cells are equipped with cytotoxic machinery but lack of antigen restriction and needing to be primed, they are nowadays gaining attention as an alternative to T cells to be exploited in immunotherapy. However, their usage suffers of the same limitations reported for T cells, that is the loss of immunogenicity by target cells and the difficulty to penetrate and be activated in the suppressive tumor microenvironment (TME). Several evidence showed that chemotherapy used in metastatic melanoma therapy possess immunomodulatory properties that may restore NK cells functions within TME. Here, we will discuss the capability of such chemotherapeutics to: i) up-regulate melanoma cells susceptibility to NK cell-mediated killing, ii) promote NK cells infiltration within TME, iii) target other immune cell subsets that affect NK cells activities. Alongside traditional systemic melanoma chemotherapy, a new pharmacological strategy based on nanocarriers loaded with chemotherapeutics is developing. The use of nanotechnologies represents a very promising approach to improve drug tolerability and effectiveness thanks to the targeted delivery of the therapeutic molecules. Here, we will also discuss the recent developments in using nanocarriers to deliver anti-cancer drugs within the melanoma microenvironment in order to improve chemotherapeutics effects. Overall, we highlight the possibility to use standard chemotherapeutics, possibly delivered by nanosystems, to enhance NK cells anti-tumor cytotoxicity. Combined with immunotherapies targeting NK cells, this may represent a valuable alternative approach to treat those patients that do not respond to current ICIs.

Association of Cardiovascular Disease Risk Factors with Late Cardiotoxicity and Survival in HER2-positive Breast Cancer Survivors

PURPOSE

Breast cancer and cardiovascular (CV) diseases often share the same risk factors. It is increasingly important to identify risk factors for CV events in patients with high-risk breast cancer and explore optimal treatment regimens.

EXPERIMENTAL DESIGN

Early HER2-positive breast cancer patients at our institution between January 1998 and October 2009 were reviewed. Primary outcome was late-severe-CV-event-free survival, and late severe CV events were defined as cardiovascular death, cardiomyopathy, symptomatic heart failure, and myocardial infarction developing 2+ years after breast cancer diagnosis. Kaplan-Meier plots, Cox proportional hazard regressions, and restricted mean survival time were used to evaluate outcomes.

RESULTS

We identified 2,448 consecutive eligible patients with a median follow-up time of 111.0 months (interquartile range, 52.0-151.8 months). One hundred and thirty-six patients had late severe CV events and 752 died of any cause [533 (70.9%) died of primary breast cancer; 12 (1.6%) died of cardiovascular disease]. Hypertension [HR, 1.546; 95% confidence interval (95% CI), 1.030-2.320; P = 0.036] and history of coronary artery disease (CAD; HR, 3.333; 95% CI, 1.669-6.656; P < 0.001) were associated with worse late-severe-CV-event-free survival. Anthracycline-containing regimens (HR, 1.536; 95% CI, 0.979-2.411; P = 0.062) was not a significant risk factor for CV events in multivariate analysis. Regimens containing both anthracycline and anti-HER2 therapy were prognostic for better OS (HR, 0.515; 95% CI, 0.412-0.643; P < 0.001).

CONCLUSIONS

Hypertension and CAD history were independent prognostic factors for late severe CV events. Adding anti-HER2 agents to anthracycline-containing regimens did not substantially increase the risk for late severe cardiotoxicity and conferred better overall survival.

Natural Killer Cells and Anti-Cancer Therapies: Reciprocal Effects on Immune Function and Therapeutic Response

Simple Summary

Natural Killer (NK) cells are innate lymphocytes that play an important role in the immune response against cancer. Their activity is controlled by a balance of inhibitory and activating receptors, which in cancer can be skewed to favor their suppression in support of immune escape. It is therefore imperative to find ways to optimize their antitumor functionality. In this review, we explore and discuss how their activity influences, or even mediates, the efficacy of various anti-cancer therapies and, vice versa, how their activity can be affected by these therapies. Knowledge of the mechanisms underlying these observations could provide rationales for combining anti-cancer treatments with strategies enhancing NK cell function in order to improve their therapeutic efficacy.

Abstract

Natural Killer (NK) cells are innate immune cells with the unique ability to recognize and kill virus-infected and cancer cells without prior immune sensitization. Due to their expression of the Fc receptor CD16, effector NK cells can kill tumor cells through antibody-dependent cytotoxicity, making them relevant players in antibody-based cancer therapies. The role of NK cells in other approved and experimental anti-cancer therapies is more elusive. Here, we review the possible role of NK cells in the efficacy of various anti-tumor therapies, including radiotherapy, chemotherapy, and immunotherapy, as well as the impact of these therapies on NK cell function.

ADCC against MICA/B Is Mediated against Differentiated Oral and Pancreatic and Not Stem-Like/Poorly Differentiated Tumors by the NK Cells; Loss in Cancer Patients due to Down-Modulation of CD16 Receptor

Tumor cells are known to upregulate major histocompatibility complex-class I chain related proteins A and B (MICA/B) expression under stress conditions or due to radiation exposure. However, it is not clear whether there are specific stages of cellular maturation in which these ligands are upregulated or whether the natural killer (NK) cells differentially target these tumors in direct cytotoxicity or antibody-dependent cell cytotoxicity (ADCC). We used freshly isolated primary and osteoclast (OCs)-expanded NK cells to determine the degree of direct cytotoxicity or of ADCC using anti-MICA/B monoclonal antibodies (mAbs) against oral stem-like/poorly-differentiated oral squamous cancer stem cells (OSCSCs) and Mia PaCa-2 (MP2) pancreatic tumors as well as their well-differentiated counterparts: namely, oral squamous carcinoma cells (OSCCs) and pancreatic PL12 tumors. By using phenotypic and functional analysis, we demonstrated that OSCSCs and MP2 tumors were primary targets of direct cytotoxicity by freshly isolated NK cells and not by ADCC mediated by anti-MICA/B mAbs, which was likely due to the lower surface expression of MICA/B. However, the inverse was seen when their MICA/B-expressing differentiated counterparts, OSCCs and PL12 tumors, were used in direct cytotoxicity and ADCC, in which there was lower direct cytotoxicity but higher ADCC mediated by the NK cells. Differentiation of the OSCSCs and MP2 tumors by NK cell-supernatants abolished the direct killing of these tumors by the NK cells while enhancing NK cell-mediated ADCC due to the increased expression of MICA/B on the surface of these tumors. We further report that both direct killing and ADCC against MICA/B expressing tumors were significantly diminished by cancer patients' NK cells. Surprisingly, OC-expanded NK cells, unlike primary interleukin-2 (IL-2) activated NK cells, were found to kill OSCCs and PL12 tumors, and under these conditions, we did not observe significant ADCC using anti-MICA/B mAbs, even though the tumors expressed a higher surface expression of MICA/B. In addition, differentiated tumor cells also expressed higher levels of surface epidermal growth factor receptor (EGFR) and programmed death-ligand 1(PDL1) and were more susceptible to NK cell-mediated ADCC in the presence of anti-EGFR and anti-PDL1 mAbs compared to their stem-like/poorly differentiated counterparts. Overall, these results suggested the possibility of CD16 receptors mediating both direct cytotoxicity and ADCC, resulting in the competitive use of these receptors in either direct killing or ADCC, depending on the differentiation status of tumor cells and the stage of maturation and activation of NK cells.

Liposomal Delivery of Mitoxantrone and a Cholesteryl Indoximod Prodrug Provides Effective Chemo-immunotherapy in Multiple Solid Tumors

We developed a custom-designed liposome carrier for codelivery of a potent immunogenic cell death (ICD) stimulus plus an inhibitor of the indoleamine 2,3-dioxygenase (IDO-1) pathway to establish a chemo-immunotherapy approach for solid tumors in syngeneic mice. The carrier was constructed by remote import of the anthraquinone chemotherapeutic agent, mitoxantrone (MTO), into the liposomes, which were further endowed with a cholesterol-conjugated indoximod (IND) prodrug in the lipid bilayer. For proof-of-principle testing, we used IV injection of the MTO/IND liposome in a CT26 colon cancer model to demonstrate the generation of a robust immune response, characterized by the appearance of ICD markers (CRT and HMGB-1) as well as evidence of cytotoxic cancer cell death, mediated by perforin and granzyme B. Noteworthy, the cytotoxic effects involved natural killer (NK) cell, which suggests a different type of ICD response. The immunotherapy response was significantly augmented by codelivery of the IND prodrug, which induced additional CRT expression, reduced number of Foxp3+ Treg, and increased perforin release, in addition to extending animal survival beyond the effect of an MTO-only liposome. The outcome reflects the improved pharmacokinetics of MTO delivery to the cancer site by the carrier. In light of the success in the CT26 model, we also assessed the platform efficacy in further breast cancer (EMT6 and 4T1) and renal cancer (RENCA) models, which overexpress IDO-1. Encapsulated MTO delivery was highly effective for inducing chemo-immunotherapy responses, with NK participation, in all tumor models. Moreover, the growth inhibitory effect of MTO was enhanced by IND codelivery in EMT6 and 4T1 tumors. All considered, our data support the use of encapsulated MTO delivery for chemo-immunotherapy, with the possibility to boost the immune response by codelivery of an IDO-1 pathway inhibitor.

The prognostic and predictive role of the neutrophil-to-lymphocyte ratio and the monocyte-to-lymphocyte ratio in early breast cancer, especially in the HER2+ subtype

Purpose

The aim of this study was to investigate the prognostic impact of two systemic inflammatory markers, the neutrophil-to-lymphocyte ratio (NLR) and the monocyte-to-lymphocyte ratio (MLR), and their possible predictive role regarding the efficacy of adjuvant trastuzumab, in 209 early breast cancer cases, 107 of which were HER2-positive.

Methods

Baseline NLR and MLR values were divided into two groups, high and low, according to cut-off-points determined from the ROC curve (2.2 for NLR and 0.22 for MLR). Cox’s model was utilized for survival analyses.

Results

High NLR and MLR correlated with poor overall survival (OS) and breast cancer specific survival (BCSS) among all the patients (p ≤ 0.030). Among the HER2+ patients whose adjuvant treatment did not include trastuzumab (n = 64), the survival rates were remarkably lower in patients with a high NLR as compared to those with low; 31% vs. 71% for OS and 42% vs. 74% for BCSS (p ≤ 0.014). Similarly, high MLR correlated with poor survival among these patients (p ≤ 0.020). On the contrary, among the patients who had received adjuvant trastuzumab (n = 43), NLR or MLR did not correlate with survival. Furthermore, trastuzumab was beneficial for the HER2+ patients with high NLR/MLR, while the survival of the HER2+ patients with low NLR/MLR was good irrespective if they received adjuvant trastuzumab.

Conclusions

Our results suggest that trastuzumab modulates the systemic inflammatory conditions and overcomes the poor prognostic impact of high NLR/MLR. This finding may also provide a rationale for combining trastuzumab with immuno-oncological treatments in HER2+ breast cancer.

Electronic supplementary material

The online version of this article (10.1007/s10549-020-05925-7) contains supplementary material, which is available to authorized users.

Natural Killer Cell Immunotherapy for Osteosarcoma

Natural killer (NK) cells are lymphocytes of the innate immune system that have the ability to recognize malignant cells through balanced recognition of cell-surface indicators of stress and danger. Once activated through such recognition, NK cells release cytokines and induce target cell lysis through multiple mechanisms. NK cells are increasingly recognized for their role in controlling tumor progression and metastasis and as important mediators of immunotherapeutic modalities such as cytokines, antibodies, immunomodulating drugs, and stem cell transplantation. Recent advances in manipulating NK cell number, function, and genetic modification have caused renewed interest in their potential for adoptive immunotherapies, which are actively being tested in clinical trials. Here, we summarize the evidence for NK cell recognition of osteosarcoma, discuss immune therapies that are directly or indirectly dependent on NK cell function, and describe potential approaches for manipulating NK cell number and function to enhance therapy against osteosarcoma.

Recent Advances in Molecular Mechanisms of the NKG2D Pathway in Hepatocellular Carcinoma

Hepatocellular carcinoma is a common malignant tumor with high mortality. Its malignant proliferation, invasion, and metastasis are closely related to the cellular immune function of the patients. NKG2D is a key activated and type II membrane protein molecule expressed on the surface of almost all NK cells. The human NKG2D gene is 270 kb long, located at 12p12.3-p13.1, and contains 10 exons and 9 introns. The three-dimensional structure of the NKG2D monomeric protein contains two alpha-helices, two beta-lamellae, and four disulfide bonds, and its' signal of activation is transmitted mainly by the adaptor protein (DAP). NKG2D ligands, including MICA, MICB, and ULBPs, can be widely expressed in hepatoma cells. After a combination of NKG2D and DAP10 in the form of homologous two polymers, the YxxM motif in the cytoplasm is phosphorylated and then signaling pathways are also gradually activated, such as PI3K, PLCγ2, JNK-cJunN, and others. Activated NK cells can enhance the sensitivity to hepatoma cells and specifically dissolve by releasing a variety of cytokines (TNF-α and IFN-γ), perforin, and high expression of FasL, CD16, and TRAIL. NK cells may specifically bind to the over-expressed MICA, MICB, and ULBPs of hepatocellular carcinoma cells through the surface activating receptor NKG2D, which can help to accurately identify hepatoma, play a critical role in anti-hepatoma via the pathway of cytotoxic effects, and obviously delay the poor progress of hepatocellular carcinoma.

Modulation of Pulmonary Microbiota by Antibiotic or Probiotic Aerosol Therapy: A Strategy to Promote Immunosurveillance against Lung Metastases

Pulmonary immunological tolerance to inhaled particulates might create a permissive milieu for lung metastasis. Lung microbiota contribute to pulmonary tolerance; here, we explored whether its manipulation via antibiotic or probiotic aerosolization favors immune response against melanoma metastasis. In lungs of vancomycin/neomycin-aerosolized mice, a decrease in bacterial load was associated with reduced regulatory T cells and enhanced T cell and NK cell activation that paralleled a significant reduction of melanoma B16 lung metastases. Reduction of metastases also occurred in lungs transplanted with bacterial isolates from antibiotic-treated lungs. Aerosolized Lactobacillus rhamnosus strongly promoted immunity against B16 lung metastases as well. Furthermore, probiotics or antibiotics improved chemotherapy activity against advanced B16 metastases. Thus, we identify a role for lung microbiota in metastasis and show that its targeting via aerosolization is a therapy that can prevent metastases and enhance responses to chemotherapy.

Local Administration of Caloric Restriction Mimetics to Promote the Immune Control of Lung Metastases

Caloric restriction mimetics (CRMs), compounds that mimic the biochemical effects of nutrient deprivation, administered via systemic route promote antitumor effects through the induction of autophagy and the modulation of the immune microenvironment; however, collateral effects due to metabolic changes and the possible weight loss might potentially limit their administration at long term. Here, we investigated in mice local administration of CRMs via aerosol to reduce metastasis implantation in the lung, whose physiologic immunosuppressive status favors tumor growth. Hydroxycitrate, spermidine, and alpha-lipoic acid, CRMs that target different metabolic enzymes, administered by aerosol, strongly reduced implantation of intravenously injected B16 melanoma cells without overt signs of toxicity, such as weight loss and changes in lung structure. Cytofluorimetric analysis of lung immune infiltrates revealed a significant increase of alveolar macrophages and CD103+ dendritic cells in mice treated with CRMs that paralleled an increased recruitment and activation of both CD3 T lymphocytes and NK cells. These effects were associated with the upregulation of genes related to M1 phenotype, as IL-12 and STAT-1, and to the decrease of M2 genes, as IL-10 and STAT-6, in adherent fraction of lung immune infiltrate, as revealed by real-time PCR analysis. Thus, in this proof-of-principle study, we highlight the antitumor effect of CRM aerosol delivery as a new and noninvasive therapeutic approach to locally modulate immunosurveillance at the tumor site in the lung.

A high absolute lymphocyte count predicts a poor prognosis in HER-2- positive breast cancer patients treated with trastuzumab

Background: Immune responses play an important role in the development of breast cancer. Trastuzumab can activate antibody-dependent cellular cytotoxicity (ADCC) in human epidermal growth factor receptor-2 (HER-2)-positive breast cancer. Many studies have demonstrated that inflammatory markers, such as the neutrophil-to-lymphocyte ratio (NLR) and absolute lymphocyte count (ALC), are associated with prognosis in breast cancer. The aim of this study was to explore whether preoperative NLR, ALC or the absolute neutrophil count (ANC) is associated with prognosis in HER-2-positive breast cancer patients who received adjuvant trastuzumab.

Patients and methods: Three hundred sixty-seven female patients with HER-2-positive invasive breast cancer who were treated with one-year adjuvant trastuzumab were analysed in this retrospective study. Preoperative haematological parameters, clinicopathological data and survival data were obtained. The cut-off points for ALC, ANC and NLR were based on the median values. Disease-free survival (DFS) and Overall survival (OS) were analysed by the Kaplan-Meier method. Multivariable Cox regression was used to determine the independent prognostic significance of ALC, ANC and NLR.

Results: Survival analysis revealed that the 3-year DFS in patients with high ALC was 89.0%, which was significantly worse than 95.0% in patients with low ALC (p=0.014). Kaplan-Meier analysis also showed that patients with low NLR had a poorer 3-year DFS than patients with high NLR (89.7% vs 94.0%, respectively; p=0.047). Multivariate analysis showed that ALC was an independent prognostic factor for DFS (HR=2.723; 95% CI=1.211–6.122; p=0.015). Neither ANC, ALC nor NLR could predict OS independently.

Conclusion: In HER-2-positive breast cancer patients who were treated with adjuvant trastuzumab, a high ALC is significantly associated with a poor DFS.

Interaction of host immunity with HER2-targeted treatment and tumor heterogeneity in HER2-positive breast cancer

Growing evidence suggests a clear role of the host immune system in HER2+ breast cancer. In addition, HER2+ breast cancer is generally considered more immunogenic than hormone receptor-positive (HR+)/HER2-, and specific molecular HER2+ subgroups (e.g. HER2-enriched disease) are more immunogenic than others (e.g. Luminal A or B). From a clinical perspective, the immune system plays a relevant prognostic role in HER2+ breast cancer and contributes to the therapeutic effects of trastuzumab. However, as more HER2-targeted agents become available, a better understanding of the role played by the immune system in modulating therapy response to different agents will be needed. Furthermore, the recent introduction in oncology of immune checkpoint inhibitors capable of unleashing anti-tumor immune response opens new possibilities for therapeutic combinations in HER2+ breast cancer. Here, we review the current pre-clinical and clinical data on the interplay between the immune system and HER2+ breast cancer, focusing on different HER2-targeted treatments and the biological heterogeneity that exists within HER2+ disease. Finally, we discuss new therapeutic approaches exploiting the immune system to increase activity or revert resistance to HER2-targeted agents.

The Potential of Combining Tubulin-Targeting Anticancer Therapeutics and Immune Therapy

Cancer immune therapy has recently shown tremendous promise to combat many different cancers. The microtubule is a well-defined and very effective cancer therapeutic target. Interestingly, several lines of evidence now suggest that microtubules are intimately connected to the body’s immune responses. This raises the possibility that the combination of microtubule inhibitors and immune therapy can be a highly effective option for cancer treatments. However, our understanding on this potentially important aspect is still very limited, due in part to the multifaceted nature of microtubule functions. Microtubules are not only involved in maintaining cell morphology, but also a variety of cellular processes, including the movement of secretory vesicles and organelles, intracellular macromolecular assembly, signaling pathways, and cell division. Microtubule inhibitors may be subdivided into two classes: Anti-depolymerization agents such as the taxane family, and anti-polymerization agents such as colchicine and vinka alkaloids. These two different classes may have different effects on immune cell subtypes. Anti-depolymerization agents can not only induce NK cells, but also appear to inhibit T regulatory (Treg) cells. However, different inhibitors may have different functions even among the same class. For example, the doxetaxel anti-depolymerization agent up-regulates cytotoxic T cells, while paclitaxel down-regulates them. Certain anti-polymerization agents such as colchicine appear to down-regulate most immune cell types, while inducing dendritic cell maturation and increasing M1 macrophage population. In contrast, the vinblastine anti-polymerization agent activates many of these cell types, albeit down-regulating Treg cells. In this review, we focus on the various effects of tubulin inhibitors on the activities of the body’s immune system, in the hope of paving the way to develop an effective cancer therapy by combining tubulin-targeting anticancer agents and immune therapy.

Early immune modulation by single-agent trastuzumab as a marker of trastuzumab benefit

BACKGROUND

Optimising the selection of HER2-targeted regimens by identifying subsets of HER2-positive breast cancer (BC) patients who need more or less therapy remains challenging. We analysed BC samples before and after treatment with 1 cycle of trastuzumab according to the response to trastuzumab.

METHODS

Gene expression profiles of pre- and post-treatment tumour samples from 17 HER2-positive BC patients were analysed on the Illumina platform. Tumour-associated immune pathways and blood counts were analysed with regard to the response to trastuzumab. HER2-positive murine models with differential responses to trastuzumab were used to reproduce and better characterise these data.

RESULTS

Patients who responded to single-agent trastuzumab had basal tumour biopsies that were enriched in immune pathways, particularly the MHC-II metagene. One cycle of trastuzumab modulated the expression levels of MHC-II genes, which increased in patients who had a complete response on treatment with trastuzumab and chemotherapy. Trastuzumab increased the MHC-II-positive cell population, primarily macrophages, only in the tumour microenvironment of responsive mice. In patients who benefited from complete trastuzumab therapy and in mice that harboured responsive tumours circulating neutrophil levels declined, but this cell subset rose in nonresponsive tumours.

CONCLUSIONS

Short treatment with trastuzumab induces local and systemic immunomodulation that is associated with clinical outcomes.

Mechanisms Underlying the Action and Synergism of Trastuzumab and Pertuzumab in Targeting HER2-Positive Breast Cancer

Human epidermal growth factor receptor (HER) 2 (HER2) is overexpressed in 20⁻30% of breast cancers. HER2 is a preferred target for treating HER2-positive breast cancer. Trastuzumab and pertuzumab are two HER2-targeted monoclonal antibodies approved by the Food and Drug Administration (FDA) to use as adjuvant therapy in combination with docetaxel to treat metastatic HER2-positive breast cancer. Adding the monoclonal antibodies to treatment regimen has changed the paradigm for treatment of HER2-positive breast cancer. Despite improving outcomes, the percentage of the patients who benefit from the treatment is still low. Continued research and development of novel agents and strategies of drug combinations is needed. A thorough understanding of the molecular mechanisms underlying the action and synergism of trastuzumab and pertuzumab is essential for moving forward to achieve high efficacy in treating HER2-positive breast cancer. This review examined and analyzed findings and hypotheses regarding the action and synergism of trastuzumab and pertuzumab and proposed a model of synergism based on available information.

Expression and function of immune ligand-receptor pairs in NK cells and cancer stem cells: therapeutic implications

BACKGROUND

The interplay between the immune system and cancer cells has come to the forefront of cancer therapeutics, with novel immune blockade inhibitors being approved for the treatment of an increasing list of cancers. However, the majority of cancer patients still display or develop resistance to these promising drugs. It is possible that cancer stem cells (CSCs) are contributing to this therapeutic resistance. Although CSCs usually represent a small percentage of the total number of cancer cells, they are endowed with the ability of self-renewal and to produce differentiated progeny. Additionally, they have shown the capacity to establish tumors after transplantation to animals, even in small numbers. CSCs have also been found to be resistant to various anti-cancer therapies, including chemotherapy, radiation therapy and, more recently, immunotherapy. This is true despite the sensitivity of CSCs to lysis in vitro by natural killer (NK) cells, the main effector cells of the innate immune system. In this paper the expression of ligands specific for NK cells on CSCs, the intracellular network responsible for the expression of the NK cytotoxicity receptors, and the status of activation of NK cells in the tumor micro-environment are reviewed. The aim of this review is to highlight potential strategies for overcoming CSC immune resistance, thereby enhancing the efficacy of current and future anti-cancer therapies.

THERAPEUTIC IMPLICATIONS

NK cell activation in the tumor micro-environment through drugs neutralizing inhibitory immune receptors, and combined with other drugs harnessing the potential of the adaptive immune system, could be the most effective approach for attacking both stem cell and non-stem cell cancer populations.

Immunotherapy in breast cancer: An introduction

The field of breast cancer immunology has progressed tremendously over the last decade. Twenty years ago immunotherapy was not considered for the treatment of breast cancers because breast cancer was not considered immunogenic. Today we know that most patients with breast cancer have some evidence of an adaptive immune response against their tumors, detectable either in the peripheral blood or in the tumor. Moreover, immunity to breast cancer begins at the earliest stages of the disease, in some patients prior to diagnosis. Recent evidence suggests that lymphocytes infiltrating breast cancers and found in the tumor stroma are strong prognostic indicators of a beneficial disease outcome. These observations now pave the way for the integration of immunomodulation into standard of care therapy for the treatment of breast cancer.

Tumor immunotherapy: New aspects of natural killer cells

A group of impressive immunotherapies for cancer treatment, including immune checkpoint-blocking antibodies, gene therapy and immune cell adoptive cellular immunotherapy, have been established, providing new weapons to fight cancer. Natural killer (NK) cells are a component of the first line of defense against tumors and virus infections. Studies have shown dysfunctional NK cells in patients with cancer. Thus, restoring NK cell antitumor functionality could be a promising therapeutic strategy. NK cells that are activated and expanded ex vivo can supplement malfunctional NK cells in tumor patients. Therapeutic antibodies, chimeric antigen receptor (CAR), or bispecific proteins can all retarget NK cells precisely to tumor cells. Therapeutic antibody blockade of the immune checkpoints of NK cells has been suggested to overcome the immunosuppressive signals delivered to NK cells. Oncolytic virotherapy provokes antitumor activity of NK cells by triggering antiviral immune responses. Herein, we review the current immunotherapeutic approaches employed to restore NK cell antitumor functionality for the treatment of cancer.

Predicting the Efficacy of HER2-Targeted Therapies: A Look at the Host

HER2 is overexpressed in 20% of invasive breast cancers (BCs) and correlates with a more aggressive disease. Until the advent of targeted agents, HER2 was associated with worse outcomes. Rationally designed HER2-targeted agents have been developed and introduced into clinical practice for women with HER2-amplified BC, improving disease-free and overall survival for primary and metastatic tumors. Trastuzumab, a recombinant humanized anti-HER2 monoclonal antibody, combined with chemotherapy, remains the standard of care for patients with HER2-positive BCs. However, many patients do not respond to this agent, whereas newer drugs have proven to be efficacious in clinical trials. The identification of biomarkers that select sensitive tumors and patients who will benefit from these new agents would help the incorporation of these therapies, limiting the risk of side effects and overtreatment and improving the outcomes of all patients with early-stage HER2-positive BC. We review the mechanisms of action of HER2-targeting agents, focusing on the involvement of the immune system and related predictive biomarkers.

Interplay between Natural Killer Cells and Anti-HER2 Antibodies: Perspectives for Breast Cancer Immunotherapy

Overexpression of the human epidermal growth factor receptor 2 (HER2) defines a subgroup of breast tumors with aggressive behavior. The addition of HER2-targeted antibodies (i.e., trastuzumab, pertuzumab) to chemotherapy significantly improves relapse-free and overall survival in patients with early-stage and advanced disease. Nonetheless, considerable proportions of patients develop resistance to treatment, highlighting the need for additional and co-adjuvant therapeutic strategies. HER2-specific antibodies can trigger natural killer (NK) cell-mediated antibody-dependent cellular cytotoxicity and indirectly enhance the development of tumor-specific T cell immunity; both mechanisms contributing to their antitumor efficacy in preclinical models. Antibody-dependent NK cell activation results in the release of cytotoxic granules as well as the secretion of pro-inflammatory cytokines (i.e., IFNγ and TNFα) and chemokines. Hence, NK cell tumor suppressive functions include direct cytolytic killing of tumor cells as well as the regulation of subsequent antitumor adaptive immunity. Albeit tumors with gene expression signatures associated to the presence of cytotoxic lymphocyte infiltrates benefit from trastuzumab-based treatment, NK cell-related biomarkers of response/resistance to HER2-specific therapeutic antibodies in breast cancer patients remain elusive. Several variables, including (i) the configuration of the patient NK cell repertoire; (ii) tumor molecular features (i.e., estrogen receptor expression); (iii) concomitant therapeutic regimens (i.e., chemotherapeutic agents, tyrosine kinase inhibitors); and (iv) evasion mechanisms developed by progressive breast tumors, have been shown to quantitatively and qualitatively influence antibody-triggered NK cell responses. In this review, we discuss possible interventions for restoring/enhancing the therapeutic activity of HER2 therapeutic antibodies by harnessing NK cell antitumor potential through combinatorial approaches, including immune checkpoint blocking/stimulatory antibodies, cytokines and toll-like receptor agonists.

Expansion of cytotoxic natural killer cells using irradiated autologous peripheral blood mononuclear cells and anti-CD16 antibody

Natural killer (NK) cells are considered a promising strategy for cancer treatment. Various methods for large-scale NK cell expansion have been developed, but they should guarantee that no viable cells are mixed with the expanded NK cells because most methods involve cancer cells or genetically modified cells as feeder cells. We used an anti-CD16 monoclonal antibody (mAb) and irradiated autologous peripheral blood mononuclear cells (PBMCs) (IrAPs) to provide a suitable environment (activating receptor-ligand interactions) for the NK cell expansion. This method more potently expanded NK cells, and the final product was composed of highly purified NK cells with lesser T-cell contamination. The expanded NK cells showed greater upregulation of various activation receptors, CD107a, and secreted larger amounts of interferon gamma. IrAPs expressed NKG2D ligands and CD48, and coengagement of CD16 with NKG2D and 2B4 caused potent NK cell activation and proliferation. The expanded NK cells were cytotoxic toward various cancer cells in vitro and in vivo. Moreover, irradiation or a chemotherapeutic drug further enhanced this antitumor effect. Therefore, we developed an effective in vitro culture method for large-scale expansion of highly purified cytotoxic NK cells with potent antitumor activity using IrAPs instead of cancer cell-based feeder cells.

Heterogeneity of colon cancer: from bench to bedside

The large bowel shows biomolecular, anatomical and bacterial changes that proceed from the proximal to the distal tract. These changes account for the different behaviour of colon cancers arising from the diverse sides of the colon-rectum as well as for the sensitivity to the therapy, including immunotherapy. The gut microbiota plays an important role in the modulation of the immune response and differs between the right colon cancer and the left colorectal cancer. The qualitative and quantitative difference of the commensal bacteria between the right side and the left side induces epigenetic changes in the intestinal epithelial cells as well as in the resident immune population. The second player in the pathological homeostasis of colorectal cancer is the differences of the genetic features of cancer cells and the different effects that microsatellite instability, chromosomal instability and the CpG island methylator phenotype induce on the immunological organisation of the tumour microenvironment. The third player is the immunological composition of the tumour microenvironment, which changes under the influence of both genetic structures and gut microbiota. All these three players influence each other. This review describes these three aspects, highlights their interactions and discusses data from reported clinical trials.