The Role of Adaptive Immunity in the Efficacy of Targeted Cancer Therapies

Randomized, open-label, phase II, biomarker study of immune-mediated mechanism of action of neoadjuvant subcutaneous trastuzumab in patients with locally advanced, inflammatory, or early HER2-positive breast cancer-Immun-HER trial (GOIRC-01-2016)

BACKGROUND

It is possible to induce immunomodulation in HER2-positive breast cancer (BC) by modifying the route of administration of trastuzumab.

METHODS

In this multicenter randomized phase II trial, all enrolled patients (pts) with T2-T4d HER2-positive BC received 3 cycles of neoadjuvant treatment (NAT) with fluorouracil, epirubicin and cyclophosphamide every 3 weeks (q21), followed by docetaxel/pertuzumab plus intravenous trastuzumab (arm A) or, docetaxel/pertuzumab plus subcutaneous (SC) trastuzumab (arm B) q21x4 cycles. After surgical operation, each pt was treated with trastuzumab q21x14 cycles using the same SC or intravenous formulation of NAT. Primary endpoint was the proportion of subjects with high stromal tumor-infiltrating lymphocytes (sTILs) in postneoadjuvant residual disease (RD).

RESULTS

Sixty-three pts (31 (arm A) and 32 (arm B)) were enrolled. Pathological complete response was obtained by 20/31 pts (64.5%; 95% CI 45.4% to 80.1%) in arm A and 19/32 pts (59.4%; 95% CI 40.1% to 76.3%) in arm B. High sTILs were observed in 27% and 46% of postneoadjuvant residual tumors in arms A and B, respectively. CD8+ T cells increased significantly in RDs of both arms (p=0.014 and 0.002 for arm A and B, respectively), whereas a significant decline in the level of CD4+ FoxP3+ regulatory T cells was observed only in arm B (p=0.016). A significant upregulation of PD-1 on sTILs was found in RD of pts enrolled in arm B (p=0.012), while programmed death-ligand 1 (PD-L1) was significantly overexpressed in residual tumors of arm A (p=0.02). A strong negative correlation was reported in arm B between expression of PD-L1 on pretreatment sTILs and CD3 expression on sTILs in RD (τ: -0.73). Grade≥3 AE incidence rates were similar between the two arms.

CONCLUSIONS

SC trastuzumab induced relevant sTILs enrichment, with favorable variations of immune parameters in HER2-positive BC pts with RD after NAT. Novel immunotherapy strategies should be tested to achieve SC-specific, antitumor immune response.

TRIAL REGISTRATION NUMBER

NCT03144947, and EudraCT number: 2016-000435-41.

Structure and functions of Mer, an innate immune checkpoint

Immunotherapy is a promising therapeutic tool that promotes the elimination of cancerous cells by a patient's own immune system. However, in the clinical setting, the number of cancer patients benefitting from immunotherapy is limited. Identification and targeting of other immune subsets, such as tumor-associated macrophages, and alternative immune checkpoints, like Mer, may further limit tumor progression and therapy resistance. In this review, we highlight the key roles of macrophage Mer signaling in immune suppression. We also summarize the role of pro-inflammatory (M1) and anti-inflammatory (M2) phenotypes in tumor onset and progression and how Mer structure and activation can be targeted therapeutically to alter activation state. Preclinical and clinical studies focusing on Mer kinase inhibition have demonstrated the potential of targeting this innate immune checkpoint, leading to improved anti-tumor responses and patient outcomes.

Immune plasticity in pregnancy-associated breast cancer tumorigenesis

Pregnancy-associated breast cancer (PrBC) is a rare tumor that requires complex management. The coexistence of cancer and pregnancy involves several proliferative, invasive, and immune tolerance mechanisms that are shared between the two conditions. In normal pregnancy, successful fetal development is achieved through suppression of the maternal immune response toward the fetus. Similar immunosuppressive patterns during the malignant transformation supporting tumor growth, progression, and metastasis are also exhibited by tumors. An improved understanding of the immunosuppressive mechanisms and pathways underlying the immunological synergy in PrBC could lead to the identification of novel biomarkers that potentially improve patients' clinical management. In this review article, we outline some of the paramount features of immune plasticity during pregnancy, discussing the similarities shared between normal pregnancy and breast cancer in terms of immune suppression mechanisms. Emphasis is also placed on how the current knowledge of the immune milieu of these conditions may be translated into consequent therapeutic opportunities.

Mechanisms of Therapeutic Antitumor Monoclonal Antibodies

Monoclonal antibodies (mAb) are a major component of cancer therapy. In this review, we summarize the different therapeutic mAbs that have been successfully developed against various tumor-expressed antigens and examine our current understanding of their different mechanisms of antitumor action. These mechanisms of action (MOA) largely center on the stimulation of different innate immune effector processes, which appear to be principally responsible for the efficacy of most unconjugated mAb therapies against cancer. This is evident in studies of mAbs targeting antigens for hematologic cancers, with emerging data also demonstrating the critical nature of innate immune-mediated mechanisms in the efficacy of anti-HER2 mAbs against solid HER2+ cancers. Although HER2-targeted mAbs were originally described as inhibitors of HER2-mediated signaling, multiple studies have since demonstrated these mAbs function largely through their engagement with Fc receptors to activate innate immune effector functions as well as complement activity. Next-generation mAbs are capitalizing on these MOAs through improvements to enhance Fc-activity, although regulation of these mechanisms may vary in different tumor microenvironments. In addition, novel antibody-drug conjugates have emerged as an important means to activate different MOAs. Although many unknowns remain, an improved understanding of these immunologic MOAs will be essential for the future of mAb therapy and cancer immunotherapy.

Type I IFN Activating Type I Dendritic Cells for Antitumor Immunity

Immune checkpoint inhibitors are successful immunotherapy modalities that enhance CD8⁺ T-cell responses. Although T cells are initially primed in draining lymph nodes, the mechanisms that underlie their reactivation inside the tumor microenvironment are less clear. Recent studies have found that not only is the cross-priming of conventional type 1 dendritic cells (cDC1) required to initiate CD8⁺ T-cell responses during tumor progression, but it also plays a central role in immunotherapy-mediated reactivation of tumor-specific CD8⁺ T cells for tumor regression. Moreover, many cancer treatment modalities trigger type I IFN responses, which play critical roles in boosting cDC1 cross-priming and CD8⁺ T-cell reactivation. Inducing type I IFNs within tumors can overcome innate immune resistance and activate antitumor adaptive immunity. Here, we review recent studies on how type I IFN-cDC1 cross-priming reactivates CD8⁺ T cells and contributes to tumor control by cancer immunotherapy.

Life and Death Decision-Making by p53 and Implications for Cancer Immunotherapy

The tumor-suppressor protein p53 is mutated in approximately half of all cancers, whereas the p53 signaling network is perturbed in almost all cancers. In response to different stress stimuli, p53 selectively activates genes to elicit a cell survival or cell death response. How p53 makes the decision between life and death remains a fascinating question and an exciting field of research. Understanding how this decision is made has major implications for improving cancer treatments, particularly in recently evolved immune checkpoint inhibition therapy. We highlight progress and challenges in understanding the mechanisms governing the p53 life and death decision-making process, and discuss how this decision is relevant to immune system regulation. Finally, we discuss how knowledge of the p53 pro-survival and pro-death decision node can be applied to optimize immune checkpoint inhibitor therapy for cancer treatment.

Systemic immunobiological, immunosuppressant, and oncologic agents for the treatment of dermatologic diseases during the SARS-CoV-2 (COVID-19) pandemic emergency: A quick review for a quick consultation

The precision medicine era has helped to better manage patients with immunological and oncological diseases, improving the quality of life of this class of patients. Regarding the management of these patients and positivity to severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2), currently, limited data are available and information is evolving. In this quick review, we have analyzed the mechanisms of action and related infective risk of drugs used for the treatment of immune‐mediated and oncologic skin conditions during the daily clinical practice. In general, immunosuppressant and antineoplastic agents for dermatologic treatments do not require suspension and do not require special measures, if not those commonly observed. In the case of a coronavirus disease (COVID‐19) patient with complications (such as pneumonia, respiratory failure), treatment suspension should always be considered after taking into account the general condition of the patient, the risk‐benefit ratio, and the pathophysiology of COVID‐19 infection. The COVID‐19 emergency pandemic does not imply undertreatment of existing skin conditions, which together with the SARS‐CoV‐2 infection may jeopardize the patient's life.

Role of innate and adaptive immunity in the efficacy of anti-HER2 monoclonal antibodies for HER2-positive breast cancer

Anti-HER2 monoclonal antibodies (mAbs) such as trastuzumab are effective for all stages of HER2-positive breast cancer (BC). However, intrinsic or acquired resistance to these drugs may occur in a significant number of patients (pts) and, except for HER2 status, no validated predictive factors of response/resistance have been identified to date. This lack is in part due to the not yet fully elucidated mechanism of action of mAbs in vivo. Increasing evidence suggests a significant contribution of both innate and adaptive immunity to the antitumor effects of mAbs. The aim of this review was to describe the role of innate and adaptive immunity in the efficacy of anti-HER2 mAbs and to report known and novel strategies to be used for optimizing immune effects of anti-HER2 therapies for HER2-positive BC.

Targeting innate sensing in the tumor microenvironment to improve immunotherapy

The innate immune sensing pathways play critical roles in the defense against pathogen infection, but their roles in cancer immunosurveillance and cancer therapies are less defined. We propose that defective innate immune sensing inside the tumor microenvironment might limit T-cell responses to immunotherapy. A recent mechanistic understanding of conventional therapies revealed that both innate immune sensing and T-cell responses are essential for optimal antitumor efficacy. T-cell-based immunotherapy, particularly immune checkpoint blockade, has achieved great success in reactivating antitumor immune responses to lead to tumor regression, but only in a small fraction of patients. Therefore, incorporating conventional therapy that can increase innate sensing and immunotherapy should lead to promising strategies for cancer patients. Here, we review the innate sensing pathways related to cancer initiation/progression and therapies, summarize the recent key findings in innate immune sensing related to conventional therapies, evaluate current combination strategies, and highlight the potential issues of combinational therapies in terms of antitumor efficacy and toxicities.

Multifaceted Role of the Placental Growth Factor (PlGF) in the Antitumor Immune Response and Cancer Progression

The sharing of molecules function that affects both tumor growth and neoangiogenesis with cells of the immune system creates a mutual interplay that impairs the host’s immune response against tumor progression. Increasing evidence shows that tumors are able to create an immunosuppressive microenvironment by recruiting specific immune cells. Moreover, molecules produced by tumor and inflammatory cells in the tumor microenvironment create an immunosuppressive milieu able to inhibit the development of an efficient immune response against cancer cells and thus fostering tumor growth and progression. In addition, the immunoediting could select cancer cells that are less immunogenic or more resistant to lysis. In this review, we summarize recent findings regarding the immunomodulatory effects and cancer progression of the angiogenic growth factor namely placental growth factor (PlGF) and address the biological complex effects of this cytokine. Different pathways of the innate and adaptive immune response in which, directly or indirectly, PlGF is involved in promoting tumor immune escape and metastasis will be described. PlGF is important for building up vascular structures and functions. Although PlGF effects on vascular and tumor growth have been widely summarized, its functions in modulating the immune intra-tumoral microenvironment have been less highlighted. In agreement with PlGF functions, different antitumor strategies can be envisioned.

Exploiting vulnerabilities in cancer signalling networks to combat targeted therapy resistance

Drug resistance remains one of the greatest challenges facing precision oncology today. Despite the vast array of resistance mechanisms that cancer cells employ to subvert the effects of targeted therapy, a deep understanding of cancer signalling networks has led to the development of novel strategies to tackle resistance both in the first-line and salvage therapy settings. In this review, we provide a brief overview of the major classes of resistance mechanisms to targeted therapy, including signalling reprogramming and tumour evolution; our discussion also focuses on the use of different forms of polytherapies (such as inhibitor combinations, multi-target kinase inhibitors and HSP90 inhibitors) as a means of combating resistance. The promise and challenges facing each of these polytherapies are elaborated with a perspective on how to effectively deploy such therapies in patients. We highlight efforts to harness computational approaches to predict effective polytherapies and the emerging view that exceptional responders may hold the key to better understanding drug resistance. This review underscores the importance of polytherapies as an effective means of targeting resistance signalling networks and achieving durable clinical responses in the era of personalised cancer medicine.

Protective immunity elicited by measles vaccine exerts anti-tumor effects on measles virus hemagglutinin gene-modified cancer cells in a mouse model

PURPOSE

Measles vaccine is widely used in China to prevent the measles virus (MV) infection. People immunized with measles vaccine can obtain long-term protective immunity. Measles virus surface glycoprotein hemagglutinin (H) can also induce MV-specific immune responses. However, little is known about whether the existence of the protective immune system against MV in the host can exert anti-tumor effects and whether the MV-H gene can serve as a therapeutic gene.

METHODS

We first vaccinated mice with measles vaccine, then inoculated them with MV-H protein-expressing tumor cells and observed the rate of tumor formation. We also treated mice with H protein-expressing tumor cells with measles vaccine and assessed tumor size and overall survival.

RESULTS

Active vaccination using measles vaccine not only protected mice from developing tumors, but also eradicated established tumors. Measles vaccine elicited H-specific IFN-γ, TNF-α and granzyme B-producing CD8+ T cells and increased cytotoxic T lymphocyte (CTL) activity specific for H antigen, which provided a strong therapeutic benefit against H protein-expressing tumors. In addition, measles vaccine decreased the population of myeloid-derived suppressor cells (MDSCs) and regulatory T cells (Tregs).

CONCLUSIONS

Our study demonstrated that tumor cells expressing H protein could activate the immune memory response against MV, which exerted specific anti-tumor effects, and indicated that the MV-H gene can be used as a potential therapeutic gene for cancer gene therapy.

Addressing current challenges in cancer immunotherapy with mathematical and computational modelling

The goal of cancer immunotherapy is to boost a patient's immune response to a tumour. Yet, the design of an effective immunotherapy is complicated by various factors, including a potentially immunosuppressive tumour microenvironment, immune-modulating effects of conventional treatments and therapy-related toxicities. These complexities can be incorporated into mathematical and computational models of cancer immunotherapy that can then be used to aid in rational therapy design. In this review, we survey modelling approaches under the umbrella of the major challenges facing immunotherapy development, which encompass tumour classification, optimal treatment scheduling and combination therapy design. Although overlapping, each challenge has presented unique opportunities for modellers to make contributions using analytical and numerical analysis of model outcomes, as well as optimization algorithms. We discuss several examples of models that have grown in complexity as more biological information has become available, showcasing how model development is a dynamic process interlinked with the rapid advances in tumour-immune biology. We conclude the review with recommendations for modellers both with respect to methodology and biological direction that might help keep modellers at the forefront of cancer immunotherapy development.

High-throughput sequencing of the immune repertoire in oncology: Applications for clinical diagnosis, monitoring, and immunotherapies

The diagnostic, monitoring and therapeutic options for cancers currently remain limited. These limitations represent a large threat to human health. Adaptive immunity, which is dependent on diverse repertoires of B cell receptors (BCRs) and T cell receptors (TCRs), plays a critical role in the anti-tumor immune response. Modulation and surveillance of adaptive immunity has become a powerful weapon to combat cancers. Recently, the high-throughput sequencing of immune repertoire (HTS-IR) technology, which provides a robust tool for deep sequencing repertoires of BCRs or TCRs, has been applied in the development of tumor biomarkers and immunotherapeutics for cancers. This review will first provide an overview of the advancement of HTS-IR technology at the population-cell and single-cell levels. It will then provide a current summary of the applications of HTS-IR technology in the diagnosis and monitoring of minimal residual disease (MRD), focusing on immune reconstitution after the treatment of allogeneic hematopoietic stem cell transplantation (allo-HSCT) in B/T-cell malignancies, and the precise detection of tumor-infiltrating lymphocytes (TILs) in non-B/T-cell malignancies. Finally, current advances of HTS-IR technology in cancer immunotherapeutic applications, such as therapeutic antibodies, CAR-T cell based-adoptive immunotherapies, and neoantigen-specific TCR-T cell-based adoptive immunotherapies, will be introduced.

Post-Translational Peptide Splicing and T Cell Responses

CD8⁺ T cell specificity depends on the recognition of MHC class I-epitope complexes at the cell surface. These epitopes are mainly produced via degradation of proteins by the proteasome, generating fragments of the original sequence. However, it is now clear that proteasomes can produce a significant portion of epitopes by reshuffling the antigen sequence, thus expanding the potential antigenic repertoire. MHC class I-restricted spliced epitopes have been described in tumors and infections, suggesting an unpredicted relevance of these peculiar peptides. We review current knowledge about proteasome-catalyzed peptide splicing (PCPS), the emerging rules governing this process, and the potential implications for our understanding and therapeutic use of CD8⁺ T cells, as well as mechanisms generating other non-canonical antigenic epitopes targeted by the T cell response.

Significantly mutated genes and regulatory pathways in SCLC-a meta-analysis

Small cell lung cancer (SCLC) accounts for approximately 15% of all lung cancers and demands effective targeted therapeutic strategies. In this meta-analysis study, we aim to identify significantly mutated genes and regulatory pathways to help us better understand the progression of SCLC and to identify potential biomarkers. Besides ranking genes based on their mutation frequencies, we sought to identify statistically significant mutations in SCLC with the MutSigCV software. Our analysis identified several genes with relatively low mutation frequency, including PTEN, as highly significant (p < 0.001), suggesting these genes may play an important role in the progression of SCLC. Our results also indicated mutations in genes involved in the axon guidance pathways likely play an important role in SCLC progression. In addition, we observed that the mutation rate was significantly higher in samples with RB1 gene mutated when compared to samples with wild type RB1, suggesting that RB1 status has significant impact on the mutation profile and disease progression in SCLC.

Inflammation Caused by Nanosized Delivery Systems: Is There a Benefit?

Secondary macrophage cytotoxicity induced by nanoparticles was described before. The study aim was to investigate the role of secondary cytotoxic effect in a macrophage-lung cancer coculture model after nanoparticle treatment in the presence and absence of anti-inflammatory drugs. An in vitro coculture model composed of confluent alveolar macrophage MH-S and A-549 lung cancer cells separated by a 0.4 μm porous membrane was used in the study. Macrophages were treated with two sizes of gelatin nanoparticles and two sizes of poly(isobutyl cyanoacrylate) (PIBCA) nanoparticles, with and without doxorubicin as a chemotherapeutic drug. The treatment effect with and without the presence of anti-inflammatory drug was studied using an MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay. The model drugs were ibuprofen, celecoxib, prednisolone, dexamethasone, and methotrexate. Different nanoparticles in different sizes were synthesized with a range of physicochemical characteristics. Doxorubicin loaded nanoparticles were prepared with an entrapment efficiency of 82-83% for PIBCA and 39-42% for gelatin. Nanoparticle treatment of macrophages showed a secondary cytotoxic effect on A-549 cancer cells at 24 and 36 h, with a drop in cell viability of 40-62%. However, this effect was significantly reduced to 10-48% if the macrophages were exposed to anti-inflammatory drugs. When ibuprofen and celecoxib were used the cell viability rebounded between 24 and 36 h. For prednisolone, dexamethasone, and methotrexate the cell viability dropped further between 24 and 36 h. Macrophages exposed to nanoparticles show secondary cytotoxicity, which has a significant antitumor effect in the microclimate of the coculture model. The beneficial nanoparticle treatment effect was significantly reduced if nonsteroidal anti-inflammatory drugs (NSAIDs), glucocorticoids, or methotrexate was given at the same time. The data suggest that anti-inflammatory treatments can decrease the carrier-induced macrophage cytotoxicity and its antitumor effectiveness with chemotherapy.

Combinatorial approach to cancer immunotherapy: strength in numbers

Immune-checkpoint blockade therapy with antibodies targeting CTLA-4 and PD-1 has revolutionized melanoma treatment by eliciting responses that can be remarkably durable and is now advancing to other malignancies. However, not all patients respond to immune-checkpoint inhibitors. Extensive preclinical evidence suggests that combining immune-checkpoint inhibitors with other anti-cancer treatments can greatly improve the therapeutic benefit. The first clinical success of the combinatorial approach to cancer immunotherapy was demonstrated using a dual-checkpoint blockade with CTLA-4 and PD-1 inhibitors, which resulted in accelerated FDA approval of this therapeutic regimen. In this review, we discuss the combinations of current and emerging immunotherapeutic agents in clinical and preclinical development and summarize the insights into potential mechanisms of synergistic anti-tumor activity gained from animal studies. These promising combinatorial partners for the immune-checkpoint blockade include therapeutics targeting additional inhibitory receptors of T cells, such as TIM-3, LAG-3, TIGIT, and BTLA, and agonists of T cell costimulatory receptors 4-1BB, OX40, and GITR, as well as agents that promote cancer cell recognition by the immune system, such as tumor vaccines, IDO inhibitors, and agonists of the CD40 receptor of APCs. We also review the therapeutic potential of regimens combining the immune-checkpoint blockade with therapeutic interventions that have been shown to enhance immunogenicity of cancer cells, including oncolytic viruses, RT, epigenetic therapy, and senescence-inducing therapy.