Local therapy of cancer with free IL-2

Immune modulation in malignant pleural effusion: from microenvironment to therapeutic implications

Immune microenvironment and immunotherapy have become the focus and frontier of tumor research, and the immune checkpoint inhibitors has provided novel strategies for tumor treatment. Malignant pleural effusion (MPE) is a common end-stage manifestation of lung cancer, malignant pleural mesothelioma and other thoracic malignancies, which is invasive and often accompanied by poor prognosis, affecting the quality of life of affected patients. Currently, clinical therapy for MPE is limited to pleural puncture, pleural fixation, catheter drainage, and other palliative therapies. Immunization is a new direction for rehabilitation and treatment of MPE. The effusion caused by cancer cells establishes its own immune microenvironment during its formation. Immune cells, cytokines, signal pathways of microenvironment affect the MPE progress and prognosis of patients. The interaction between them have been proved. The relevant studies were obtained through a systematic search of PubMed database according to keywords search method. Then through screening and sorting and reading full-text, 300 literatures were screened out. Exclude irrelevant and poor quality articles, 238 literatures were cited in the references. In this study, the mechanism of immune microenvironment affecting malignant pleural effusion was discussed from the perspectives of adaptive immune cells, innate immune cells, cytokines and molecular targets. Meanwhile, this study focused on the clinical value of microenvironmental components in the immunotherapy and prognosis of malignant pleural effusion.

Locoregional drug delivery for cancer therapy: Preclinical progress and clinical translation

Systemic drug delivery is the current clinically preferred route for cancer therapy. However, challenges associated with tumor localization and off-tumor toxic effects limit the clinical effectiveness of this route. Locoregional drug delivery is an emerging viable alternative to systemic therapies. With the improvement in real-time imaging technologies and tools for direct access to tumor lesions, the clinical applicability of locoregional drug delivery is becoming more prominent. Theoretically, locoregional treatments can bypass challenges faced by systemic drug delivery. Preclinically, locoregional delivery of drugs has demonstrated enhanced therapeutic efficacy with limited off-target effects while still yielding an abscopal effect. Clinically, an array of locoregional strategies is under investigation for the delivery of drugs ranging in target and size. Locoregional tumor treatment strategies can be classified into two main categories: 1) direct drug infusion via injection or implanted port and 2) extended drug elution via injected or implanted depot. The number of studies investigating locoregional drug delivery strategies for cancer treatment is rising exponentially, in both preclinical and clinical settings, with some approaches approved for clinical use. Here, we highlight key preclinical advances and the clinical relevance of such locoregional delivery strategies in the treatment of cancer. Furthermore, we critically analyze 949 clinical trials involving locoregional drug delivery and discuss emerging trends.

IL-2-armored peptide-major histocompatibility class I bispecific antibodies redirect antiviral effector memory CD8+ T cells to induce potent anti-cancer cytotoxic activity with limited cytokine release

T cell engagers (TCEs) are becoming an integral class of biological therapeutic owing to their highly potent ability to eradicate cancer cells. Nevertheless, the widespread utility of classical CD3-targeted TCEs has been limited by narrow therapeutic index (TI) linked to systemic CD4+ T cell activation and aberrant cytokine release. One attractive approach to circumvent the systemic activation of pan CD3+ T cells and reduce the risk of cytokine release syndrome is to redirect specific subsets of T cells. A promising strategy is the use of peptide-major histocompatibility class I bispecific antibodies (pMHC-IgGs), which have emerged as an intriguing modality of TCE, based on their ability to selectively redirect highly reactive viral-specific effector memory cytotoxic CD8+ T cells to eliminate cancer cells. However, the relatively low frequency of these effector memory cells in human peripheral blood mononuclear cells (PBMCs) may hamper their redirection as effector cells for clinical applications. To mitigate this potential limitation, we report here the generation of a pMHC-IgG derivative known as guided-pMHC-staging (GPS) carrying a covalent fusion of a monovalent interleukin-2 (IL-2) mutein (H16A, F42A). Using an anti-epidermal growth factor receptor (EGFR) arm as a proof-of-concept, tumor-associated antigen paired with a single-chain HLA-A *02:01/CMVpp65 pMHC fusion moiety, we demonstrate in vitro that the IL-2-armored GPS modality robustly expands CMVpp65-specific CD8+ effector memory T cells and induces potent cytotoxic activity against target cancer cells. Similar to GPS, IL-2-armored GPS molecules induce modulated T cell activation and reduced cytokine release profile compared to an analogous CD3-targeted TCE. In vivo we show that IL-2-armored GPS, but not the corresponding GPS, effectively expands grafted CMVpp65 CD8+ T cells from unstimulated human PBMCs in an NSG mouse model. Lastly, we demonstrate that the IL-2-armored GPS modality exhibits a favorable developability profile and monoclonal antibody-like pharmacokinetic properties in human neonatal Fc receptor transgenic mice. Overall, IL-2-armored GPS represents an attractive approach for treating cancer with the potential for inducing vaccine-like antiviral T cell expansion, immune cell redirection as a TCE, and significantly widened TI due to reduced cytokine release.

Cancer Immunotherapy Using Bioengineered Micro/Nano Structured Hydrogels

Hydrogels, a class of materials with a 3D network structure, are widely used in various applications of therapeutic delivery, particularly cancer therapy. Micro and nanogels as miniaturized structures of the bioengineered hydrogels may provide extensive benefits over the common hydrogels in encapsulation and controlled release of small molecular drugs, macromolecular therapeutics, and even cells. Cancer immunotherapy is rapidly developing, and micro/nanostructured hydrogels have gained wide attention regarding their engineered payload release properties that enhance systemic anticancer immunity. Additionally, they are a great candidate due to their local administration properties with a focus on local immune cell manipulation in favor of active and passive immunotherapies. Although applied locally, such micro/nanostructured can also activate systemic antitumor immune responses by releasing nanovaccines safely and effectively inhibiting tumor metastasis and recurrence. However, such hydrogels are mostly used as locally administered carriers to stimulate the immune cells by releasing tumor lysate, drugs, or nanovaccines. In this review, the latest developments in cancer immunotherapy are summarized using micro/nanostructured hydrogels with a particular emphasis on their function depending on the administration route. Moreover, the potential for clinical translation of these hydrogel-based cancer immunotherapies is also discussed.

Viral Vectors Expressing Interleukin 2 for Cancer Immunotherapy

Interleukin 2 (IL-2) plays a crucial role in T cell growth and survival, enhancing the cytotoxic activity of natural killer and cytotoxic T cells and thus functioning as a versatile master proinflammatory anticancer cytokine. The FDA has approved IL-2 cytokine therapy for the treatment of metastatic melanoma and metastatic renal cell carcinoma. However, IL-2 therapy has significant constraints, including a short serum half-life, low tumor accumulation, and life-threatening toxicities associated with high doses. Oncolytic viruses (OVs) offer a promising option for cancer immunotherapy, selectively targeting and destroying cancer cells while sparing healthy cells. Numerous studies have demonstrated the successful delivery of IL-2 to the tumor microenvironment without compromising safety using OVs such as vaccinia, Sendai, parvo, Newcastle disease, tanapox, and adenoviruses. Additionally, by engineering OVs to coexpress IL-2 with other anticancer transgenes, the immune properties of IL-2 can be further enhanced. Preclinical and clinical studies have shown promising antitumor effects of IL-2-expressing viral vectors, either alone or in combination with other anticancer therapies. This review summarizes the therapeutic potential of IL-2-expressing viral vectors and their antitumor mechanisms of action.

Exploring the contribution of pro-inflammatory cytokines to impaired wound healing in diabetes

Background

Impaired wound healing is the most common and significant complication of Diabetes. While most other complications of Diabetes have better treatment options, diabetic wounds remain a burden as they can cause pain and suffering in patients. Wound closure and repair are orchestrated by a sequence of events aided by the release of pro-inflammatory cytokines, which are dysregulated in cases of Diabetes, making the wound environment unfavorable for healing and delaying the wound healing processes. This concise review provides an overview of the dysregulation of pro-inflammatory cytokines and offers insights into better therapeutic outcomes.

Purpose of review

Although many therapeutic approaches have been lined up nowadays to treat Diabetes, there are no proper treatment modalities proposed yet in treating diabetic wounds due to the lack of understanding about the role of inflammatory mediators, especially Pro-inflammatory mediators- Cytokines, in the process of Wound healing which we mainly focus on this review.

Recent findings

Although complications of Diabetes mellitus are most reported after years of diagnosis, the most severe critical complication is impaired Wound Healing among Diabetes patients. Even though Trauma, Peripheral Artery Disease, and Peripheral Neuropathy are the leading triggering factors for the development of ulcerations, the most significant issue contributing to the development of complicated cutaneous wounds is wound healing impairment. It may even end up with amputation. Newer therapeutic approaches such as incorporating the additives in the present dressing materials, which include antimicrobial molecules and immunomodulatory cytokines is of better therapeutic value.

Summary

The adoption of these technologies and the establishment of novel therapeutic interventions is difficult since there is a gap in terms of a complete understanding of the pathophysiological mechanisms at the cellular and molecular level and the lack of data in terms of the assessment of safety and bioavailability differences in the individuals' patients. The target-specific pro-inflammatory cytokines-based therapies, either by upregulation or downregulation of them, will be helpful in the wound healing process and thereby enhances the Quality of life in patients, which is the goal of drug therapy.

Activation of Adaptive and Innate Immune Cells via Localized IL2 Cytokine Factories Eradicates Mesothelioma Tumors

PURPOSE

IL2 immunotherapy has the potential to elicit immune-mediated tumor lysis via activation of effector immune cells, but clinical utility is limited due to pharmacokinetic challenges as well as vascular leak syndrome and other life-threatening toxicities experienced by patients. We developed a safe and clinically translatable localized IL2 delivery system to boost the potency of therapy while minimizing systemic cytokine exposure.

EXPERIMENTAL DESIGN

We evaluated the therapeutic efficacy of IL2 cytokine factories in a mouse model of malignant mesothelioma. Changes in immune populations were analyzed using time-of-flight mass cytometry (CyTOF), and the safety and translatability of the platform were evaluated using complete blood counts and serum chemistry analysis.

RESULTS

IL2 cytokine factories enabled 150× higher IL2 concentrations in the local compartment with limited leakage into the systemic circulation. AB1 tumor burden was reduced by 80% after 1 week of monotherapy treatment, and 7 of 7 of animals exhibited tumor eradication without recurrence when IL2 cytokine factories were combined with anti-programmed cell death protein 1 (aPD1). Furthermore, CyTOF analysis showed an increase in CD69+CD44+ and CD69-CD44+CD62L- T cells, reduction of CD86-PD-L1- M2-like macrophages, and a corresponding increase in CD86+PD-L1+ M1-like macrophages and MHC-II+ dendritic cells after treatment. Finally, blood chemistry ranges in rodents demonstrated the safety of cytokine factory treatment and reinforced its potential for clinical use.

CONCLUSIONS

IL2 cytokine factories led to the eradication of aggressive mouse malignant mesothelioma tumors and protection from tumor recurrence, and increased the therapeutic efficacy of aPD1 checkpoint therapy. This study provides support for the clinical evaluation of this IL2-based delivery system. See related commentary by Palanki et al., p. 5010.

Maximizing response to intratumoral immunotherapy in mice by tuning local retention

Direct injection of therapies into tumors has emerged as an administration route capable of achieving high local drug exposure and strong anti-tumor response. A diverse array of immune agonists ranging in size and target are under development as local immunotherapies. However, due to the relatively recent adoption of intratumoral administration, the pharmacokinetics of locally-injected biologics remains poorly defined, limiting rational design of tumor-localized immunotherapies. Here we define a pharmacokinetic framework for biologics injected intratumorally that can predict tumor exposure and effectiveness. We find empirically and computationally that extending the tumor exposure of locally-injected interleukin-2 by increasing molecular size and/or improving matrix-targeting affinity improves therapeutic efficacy in mice. By tracking the distribution of intratumorally-injected proteins using positron emission tomography, we observe size-dependent enhancement in tumor exposure occurs by slowing the rate of diffusive escape from the tumor and by increasing partitioning to an apparent viscous region of the tumor. In elucidating how molecular weight and matrix binding interplay to determine tumor exposure, our model can aid in the design of intratumoral therapies to exert maximal therapeutic effect.

Controlled release of bioactive IL-2 from visible light photocured biodegradable elastomers for cancer immunotherapy applications

Biodegradable elastomeric controlled-release poly (decane-co-tricarballylate) (PDET) based matrices capable of maintaining the stability and bioactivity of Interleukin-2 (IL-2) through the utilization of visible-light curing and solvent-free loading of the cytokine are reported. The elastomeric devices were fabricated by intimately mixing lyophilized IL-2 powder with the acrylated prepolymer before photocrosslinking. The bioactivity of the released protein was assessed by its ability to stimulate the proliferation of the C57BL/6 mouse cytotoxic T lymphocyte, and its concentration was analysed using ELISA. The influence of changes in the polymer's physicochemical and mechanical properties on IL-2 release kinetics and bioactivity were also studied. The increase in the device's surface area and the incorporation of trehalose in the loaded lyophilized mix increased the IL-2 release rate with drug release proceeding via typical zero-order release kinetics. Moreover, the decrease in the degree of acrylation of the prepared devices increased the IL-2 release rate. The bioactivity assay showed that IL-2 retained over 94% of its initial bioactivity throughout 28 days of the release period. A new protein delivery vehicle composed of biodegradable PDET elastomers was demonstrated to be promising and effective for linear, constant, and sustained osmotic-driven release of bioactive IL-2 and other sensitive proteins and hormones.

Postoperative cancer treatments: In-situ delivery system designed on demand

The keys to the prevention of tumor recurrence after operation are the elimination of residual tumor cells and the reversal of microenvironments that induce recurrence. In the formulation of a treatment scheme, building an appropriate drug delivery system is essential. An in-situ drug delivery system (ISDDS) is regarded as an effective treatment route for postoperative use that increases drug delivery efficiency and mitigates side-effects. ISDDS technology has been considerably improved through a clearer understanding of the mechanisms of postoperative recurrence and the development of drug delivery materials. This paper describes the initiation and characteristics of postoperative recurrence mechanisms. Based on this information, design principles for ISDDS are proposed, and a variety of practical drug delivery systems that fulfil specific therapeutic needs are presented. Challenges and future opportunities related to the application of in-situ drug carriers for inhibiting cancer recurrence are also discussed.

Local Targeting of Lung-Tumor-Associated Macrophages with Pulmonary Delivery of a CSF-1R Inhibitor for the Treatment of Breast Cancer Lung Metastases

The lungs are major sites of metastases for several cancer types, including breast cancer (BC). Prognosis and quality of life of BC patients that develop pulmonary metastases are negatively impacted. The development of strategies to slow the growth and relieve the symptoms of BC lung metastases (BCLM) is thus an important goal in the management of BC. However, systemically administered first line small molecule chemotherapeutics have poor pharmacokinetic profiles and biodistribution to the lungs and significant off-target toxicity, severely compromising their effectiveness. In this work, we propose the local delivery of add-on immunotherapy to the lungs to support first line chemotherapy treatment of advanced BC. In a syngeneic murine model of BCLM, we show that local pulmonary administration (p.a.) of PLX-3397 (PLX), a colony-stimulating factor 1 receptor inhibitor (CSF-1Ri), is capable of overcoming physiological barriers of the lung epithelium, penetrating the tumor microenvironment (TME), and decreasing phosphorylation of CSF-1 receptors, as shown by the Western blot of lung tumor nodules. That inhibition is accompanied by an overall decrease in the abundance of protumorigenic (M2-like) macrophages in the TME, with a concomitant increase in the amount of antitumor (M1-like) macrophages when compared to the vehicle-treated control. These effects with PLX (p.a.) were achieved using a much smaller dose (1 mg/kg, every other day) compared to the systemic doses typically used in preclinical studies (40-800 mg/kg/day). As an additive in combination with intravenous (i.v.) administration of paclitaxel (PTX), PLX (p.a.) leads to a decrease in tumor burden without additional toxicity. These results suggested that the proposed immunochemotherapy, with regional pulmonary delivery of PLX along with the i.v. standard of care chemotherapy, may lead to new opportunities to improve treatment, quality of life, and survival of patients with BCLM.

The Impact of a New Interleukin-2-Based Immunotherapy Candidate on Urothelial Cells to Support Use for Intravesical Drug Delivery

(1) Background: The intravesical instillation of interleukin-2 (IL-2) has been shown to be very well tolerated and promising in patients with bladder malignancies. This study aims to confirm the use of a new IL-2 containing immunotherapy candidate as safe for intravesical application. IL-2, produced in mammalian cells, is glycosylated, because of its unique solubility and stability optimized for intravesical use. (2) Materials and Methods: Urothelial cells and fibroblasts were generated out of porcine bladder and cultured until they reached second passage. Afterwards, they were cultivated in renal epithelial medium (REM) and Dulbecco’s modified Eagles medium (DMEM) with the IL-2 candidate (IMS-Research) and three more types of human interleukin-2 immunotherapy products (IMS-Pure, Natural IL-2, Aldesleukin) in four different concentrations (100, 250, 500, 1000 IU/mL). Cell proliferation was analyzed by water soluble tetrazolium (WST) proliferation assay after 0, 3, and 6 days for single cell culture and co-culture. (3) Results: Proliferation assays showed that all IL-2 products induced very similar cultivation results and none of the IL-2 variants had a negative impact on the proliferation of urothelial cells and fibroblast in either concentration. (4) Conclusion: Human recombinant glycosylated IL-2 as well as human non-glycosylated IL-2 have no negative influence on the tissue cell proliferation of porcine urothelial cells and fibroblasts in vitro and represent a promising and innovative potential intravesical therapy candidate for patients in high need.

Human Mesenchymal Stem Cells Overexpressing Interleukin 2 Can Suppress Proliferation of Neuroblastoma Cells in Co-Culture and Activate Mononuclear Cells In Vitro

High-dose recombinant interleukin 2 (IL2) therapy has been shown to be successful in renal cell carcinoma and metastatic melanoma. However, systemic administration of high doses of IL2 can be toxic, causing capillary leakage syndrome and stimulating pro-tumor immune response. One of the strategies to reduce the systemic toxicity of IL2 is the use of mesenchymal stem cells (MSCs) as a vehicle for the targeted delivery of IL2. Human adipose tissue-derived MSCs were transduced with lentivirus encoding IL2 (hADSCs-IL2) or blue fluorescent protein (BFP) (hADSCs-BFP). The proliferation, immunophenotype, cytokine profile and ultrastructure of hADSCs-IL2 and hADSCs-BFP were determined. The effect of hADSCs on activation of peripheral blood mononuclear cells (PBMCs) and proliferation and viability of SH-SY5Y neuroblastoma cells after co-culture with native hADSCs, hADSCs-BFP or hADSCs-IL2 on plastic and Matrigel was evaluated. Ultrastructure and cytokine production by hADSCs-IL2 showed modest changes in comparison with hADSCs and hADSCs-BFP. Conditioned medium from hADSC-IL2 affected tumor cell proliferation, increasing the proliferation of SH-SY5Y cells and also increasing the number of late-activated T-cells, natural killer (NK) cells, NKT-cells and activated T-killers. Conversely, hADSC-IL2 co-culture led to a decrease in SH-SY5Y proliferation on plastic and Matrigel. These data show that hADSCs-IL2 can reduce SH-SY5Y proliferation and activate PBMCs in vitro. However, IL2-mediated therapeutic effects of hADSCs could be offset by the increased expression of pro-oncogenes, as well as the natural ability of hADSCs to promote the progression of some tumors.

Are aggressive epithelial cancers 'a disease' of Eutherian mammals?

Placental immune editing switches (PIES) have not evolved to prevent or to cause cancer but to make feto-maternal immune tolerance possible, which is at the very core of our placental mammalian ('Eutherian') nature. Aggressive epithelial cancers might be an unfortunate 'side effect' of this highly sophisticated biological nature. Microenvironmental properties in the placenta and decidua are thought to be a key to feto-maternal immune tolerance. Recently, in 2016-2018, we published the first human genomic and epigenomic evidence of similar gene expression profiles in immune regulatory genes in cancer (primary lobular infiltrating breast cancer and ipsilateral axillary metastatic lymph nodes) and both placenta and decidua of the same young patient with breast carcinoma during pregnancy. These findings led us to speculate that ectopic expression, or repression, of 'PIES' might be used by cancer cells during carcinogenesis or cancer progression to elude immune vigilance in spite of tumour-associated antigens or evolving neo antigenic landscapes. Cancers are well known to frequently express embryonic antigens, such as carcinoembryonic antigen, used as cancer markers and detectable in the blood circulation, or to express ectopic hormones. Why should cancer cells invent de novo complex new immune suppression mechanisms, if they could simply use innate ones developed during the long-term evolution of placental mammals in order to hide fetal paternal antigens from the mother's own immune system? Monotremata (Prototheria-like Echidnas or Platypus Ornithoryncus) are nonplacental egg-laying mammals and, in spite of rudimentary breast epithelial ducts and lobules, they are seldom reported to suffer from aggressive breast cancers.

Local Interleukin-2 Immunotherapy of Breast Cancer: Benefit and Risk in a Spontaneous Mouse Model

Earlier, naturally arising mammary cancer in BLRB female mice was shown to reproduce some key pathological characteristics of the familial set of human breast cancer. Then we advanced a novel 3S-paradigm of anticancer research that helped to develop selection criteria and to estimate benefit/risk of local interleukin-2 (IL-2) effects in this spontaneous mouse model. In this paper, the efficacy of single and triple local IL-2 doses is compared using properly selected murine BLRB females based on our previously published data. Only BLRB females bearing spontaneous mammary tumors without subclinical period were used. The tumor growth rate and recipient survival of single and triple IL-2 applications were compared with corresponding parameter values of untreated control. Tumor growth rate was decreased in both experimental groups versus control parameter values. Single IL-2 application resulted in a significant prolongation of the average survival time while triple application caused acute tumor rejection in some females decreasing the survival time of the rest of the recipients. As a result, proper treatment protocol in accurately selected females allowed increasing the complete response rate to 14% in spontaneous mouse model of breast cancer. In conclusion, our approaches may demonstrate the principle methodology developing preselection procedure for breast cancer patients for local IL-2 therapy application.

Natural Killer Cells - Their Role in Tumour Immunosurveillance

An important component of the innate immune system, the natural killer cells that originate from the lymphoid cell lineage, hold tremendous potential as an effective therapeutic tool to combat a variety of cancers. Their vast capability to kill altered cells such as opsonized cells (antibody coated), tumour cells, genotoxically changed cells without affecting the healthy cells of the body, make them an effective therapeutic agent for various types of cancers. Besides, through interplay and molecular crosstalk via several cytokines, they also augment the adaptive immune response by, promoting the differentiation, activation and recruitment of component cells of the system. With the current advance knowledge of Natural Killer (NK) cells, their receptor-ligand interactions involved in functional regulation, various mechanistic approaches involving the role of cytokines led to desired modulation of NK cell activity in a tailor-made manner, for triggering clinically relevant responces. Several strategies have been adopted by researchers, to augment the efficacy of NK cells. Still many challenges exist for increasing the therapeutic relevance of these cells.

Diagnosis and treatment of in-transit melanoma metastases

In transit metastases (ITM) from extremity or trunk melanomas are subcutaneous or cutaneous lymphatic deposits of melanoma cells, distant from the primary site but not reaching the draining nodal basin. Superficial ITM metastases develop in 5-10% of melanoma patients and are thought to be caused by cells spreading along lymphatics; ITM appear biologically different from distant cutaneous metastases, these probably due to a haematogenous dissemination. The diagnosis is usually clinical and by patients, but patients need to be adequately educated in the recognition of this clinical situation. Ultrasound or more sophisticated instrumental devices may be required if the disease develops more deeply in the soft tissues. According to AJCC 2009 staging classification, ITM are included in stages IIIb and IIIc, which are considered local advanced disease with quite poor 5-year survival rates and outcomes of 24-54% at 5 years.² Loco-regional recurrence is in fact an important risk factor for distant metastatic disease, either synchronous or metachronous. Therapy for this pattern of recurrence is less standardised then in most other clinical situations and options vary based on the volume and site of the disease. Definitive surgical resection remains the preferred therapeutic approach. However, when surgery cannot be performed with a reasonable cosmetic and functional outcome, other options must be utilized.^3-6 Treatment options are classified as local, regional or systemic. The choice of therapy depends on the number of lesions, their anatomic location, whether or not these are dermal or subcutaneous, the size and the presence or absence of extra-regional disease.

In vivo Antitumor Effect of an HPV-specific Promoter driving IL-12 Expression in an HPV 16-positive Murine Model of Cervical Cancer

Human papillomavirus (HPV) is a DNA virus that infects epithelial cells and has been implicated in the development of cervical cancer. Few therapeutic strategies have been designed for the treatment of cervical intraepithelial neoplasia, a precursor of cervical cancer. In these early stages, the HPV E2 protein is the most important viral factor involved in viral gene expression and plays crucial roles during the vegetative viral cycle in epithelial cells. Papillomavirus E2 binds specifically to palindromic ACCN₆GGT sequences, referred to as the E2 binding sites (E2BS), which are concentrated within the viral long control region, and which are responsible for regulation of the HPV protein's expression. Here, we consider E2BS as a candidate sequence to induce the expression of antiviral therapeutic genes selectively in HPV-infected cells expressing the E2 protein. This study focuses on the use of an HPV-specific promoter comprised of four E2BS to drive the expression of IL-12, leading to an antitumor effect in an HPV-positive murine tumor model. The therapeutic strategy was implemented via viral gene therapy using adenoviral vectors with recombinant E2 and IL-12 genes and E2BS-IL-12. We demonstrate that the HPV-specific promoter E2BS is functional in vitro and in vivo through transactivation of HPV E2 transcription factor.

Adenoviral Delivery of Tumor Necrosis Factor-α and Interleukin-2 Enables Successful Adoptive Cell Therapy of Immunosuppressive Melanoma

Adoptive T-cell transfer is a promising treatment approach for metastatic cancer, but efficacy in solid tumors has only been achieved with toxic pre- and postconditioning regimens. Thus, adoptive T-cell therapies would benefit from complementary modalities that enable their full potential without excessive toxicity. We aimed to improve the efficacy and safety of adoptive T-cell transfer by using adenoviral vectors for direct delivery of immunomodulatory murine cytokines into B16.OVA melanoma tumors with concomitant T-cell receptor transgenic OT-I T-cell transfer. Armed adenoviruses expressed high local and low systemic levels of cytokine when injected into B16.OVA tumors, suggesting safety of virus-mediated cytokine delivery. Antitumor efficacy was significantly enhanced with adenoviruses coding for murine interleukin-2 (mIL-2) and tumor necrosis factor-α (mTNFα) when compared with T-cell transfer alone or viruses alone. Further improvement in efficacy was achieved with a triple combination of mIL-2, mTNFα, and OT-I T-cells. Mechanistic studies suggest that mIL-2 has an important role in activating T-cells at the tumor, while mTNFα induces chemokine expression. Furthermore, adenovirus treatments enhanced tumor-infiltration of OT-I T-cells as demonstrated by SPECT/CT imaging of (111)In-labeled cells. Our results suggest the utility of cytokine-coding adenoviruses for improving the efficacy of adoptive T-cell therapies.

Breast cancer gene therapy using an adenovirus encoding human IL-2 under control of mammaglobin promoter/enhancer sequences

Interleukin-2 (IL-2) has been used clinically for the treatment of some malignancies, but the toxicities associated with systemic IL-2 therapy are a major challenge. Here we have determined whether transcriptional targeting of IL-2 to breast cancer (BrCa) using an engineered human mammaglobin promoter/enhancer (MPE2) is a feasible option for reducing IL-2-associated toxicities while still achieving a meaningful antitumor effect. We have constructed nonreplicating adenovirus vectors encoding either a reporter gene (luciferase) or human IL-2 (hIL-2) complementary DNA under control of the MPE2 sequence, the murine cytomegalovirus immediate early (MCMV) promoter or the human telomerase reverse transcriptase (hTERT) promoter. Luciferase and hIL-2 complementary DNAs under the control of the MPE2 sequence in adenovirus vectors were expressed at high levels in BrCa cells and at lower levels in normal cells of human and murine origin. Cancer specificity of the hTERT promoter was found to be similar to that of the MPE2 promoter in cells of human origin, but reduced specificity in murine cells. The MPE2 regulatory sequence demonstrated excellent tissue specificity in a mouse tumor model. Whereas the MCMV promoter-controlled IL-2 vector generated high liver toxicity in mice, the MPE2-controlled IL-2 vector generated little or no liver toxicity. Both IL-2 vectors exerted significant tumor growth delay; however, attempts to further enhance antitumor activity of the IL-2 vectors by combining with the proapoptotic drug procaspase activating compound 1 (PAC1) were unsuccessful.

Immunotherapy for urothelial cancer: from BCG to checkpoint inhibitors and beyond

Since its introduction almost 40 years ago, intravesical BCG for non-muscle invasive bladder cancer remains one of the most successful cancer immunotherapies. However, up to 40% of patients will progress after BCG therapy and develop invasive bladder cancer. Despite its extensive clinical use, we are only beginning to understand how BCG works. Here we review preclinical and clinical data that implicate BCG-induced Th1 and cytotoxic cellular immune responses in cancer regression. We propose that future immunotherapies should aim to augment Th1 and/or cellular responses in those that fail BCG therapy. We review clinical trials of immunotherapy in bladder cancer with a focus on the promising role of checkpoint blockade inhibitors that target the programmed cell death 1/programmed death-ligand 1 (PD-L1) axis and/or cytotoxic T lymphocyte antigen 4.

Radiotherapy combined with the immunocytokine L19-IL2 provides long-lasting antitumor effects

PURPOSE

Radiotherapy modifies the tumor microenvironment and causes the release of tumor antigens, which can enhance the effect of immunotherapy. L19 targets the extra domain B (ED-B) of fibronectin, a marker for tumor neoangiogenesis, and can be used as immunocytokine when coupled to IL2. We hypothesize that radiotherapy in combination with L19-IL2 provides an enhanced antitumor effect, which is dependent on ED-B expression.

EXPERIMENTAL DESIGN

Mice were injected with syngeneic C51 colon carcinoma, Lewis lung carcinoma (LLC), or 4T1 mammary carcinoma cells. Tumor growth delay, underlying immunologic parameters, and treatment toxicity were evaluated after single-dose local tumor irradiation and systemic administration of L19-IL2 or equimolar controls.

RESULTS

ED-B expression was high, intermediate, and low for C51, LLC, and 4T1, respectively. The combination therapy showed (i) a long-lasting synergistic effect for the C51 model with 75% of tumors being cured, (ii) an additive effect for the LLC model, and (iii) no effect for the 4T1 model. The combination treatment resulted in a significantly increased cytotoxic (CD8(+)) T-cell population for both C51 and LLC. Depletion of CD8(+) T cells abolished the benefit of the combination therapy.

CONCLUSIONS

These data provide the first evidence for an increased therapeutic potential by combining radiotherapy with L19-IL2 in ED-B-positive tumors. This new opportunity in cancer treatment will be investigated in a phase I clinical study for patients with an oligometastatic solid tumor (NCT02086721). An animation summarizing our results is available at https://www.youtube.com/watch?v=xHbwQuCTkRc.

Pathologic complete response to intralesional interleukin-2 therapy associated with improved survival in melanoma patients with in-transit disease

PURPOSE

Melanoma patients with in-transit disease have a high mortality rate despite various treatment strategies. The aim of this study was to validate the role of intralesional interleukin (IL)-2, to understand its mechanism of action, and to better understand factors that may influence its response.

METHODS

We retrospectively collected the clinicopathological data of 31 consecutive patients who presented to a tertiary care cancer center for treatment of in-transit melanoma with intralesional IL-2. Kaplan-Meier survival curves and multivariable Cox regression analysis were performed. Immunohistochemistry (IHC) was used to better understand the immune response to localized IL-2 therapy. Targeted next-generation sequencing was performed to genomically characterize the tumors.

RESULTS

Ten patients (10/31, 32 %) achieved a pathologic complete response (pCR), 17/21 (55 %) had a partial response, and 4/21 (19 %) had progressive disease on treatment. pCR to IL-2 therapy was associated with overall survival (log-rank p = 0.004) and improved progression-free survival (PFS) [adjusted hazard ratio (HR) 0.11; 95 % CI 0.02-0.47; p = 0.003). A higher CD8+ T cell infiltrate was identified in in-transit lesions with a pCR compared with the other lesions (mean IHC score 3.78 vs. 2.61; p = 0.01). Patients with an elevated CD8+ infiltrate demonstrated an improved PFS (unadjusted HR 0.08; 95 % CI 0.01-0.52; p = 0.008).

CONCLUSIONS

Thirty-two percent of patients achieved pCR with intralesional IL-2 therapy and had a significantly improved PFS compared with the rest of the cohort, which may be explained by a systemic CD8+ T-cell response.

The effect of interleukin-2 on canine peripheral nerve sheath tumours after marginal surgical excision: a double-blind randomized study

Background

The objective of this study was to evaluate the effect on outcomes of intraoperative recombinant human interleukin-2 injection after surgical resection of peripheral nerve sheath tumours. In this double-blind trial, 40 patients due to undergo surgical excision (<5 mm margins) of presumed peripheral nerve sheath tumours were randomized to receive intraoperative injection of interleukin-2 or placebo into the wound bed.

Results

There were no significant differences in any variable investigated or in median survival between the two groups. The median recurrence free interval was 874 days (range 48–2141 days), The recurrence-free interval and overall survival time were significantly longer in dogs that undergone the primary surgery by a specialist-certified surgeon compared to a referring veterinarian regardless of whether additional adjunct therapy was given.

Conclusion

Overall, marginal excision of peripheral nerve sheath tumours in dogs resulted in a long survival time, but adjuvant treatment with recombinant human interleukin-2 (rhIL-2) did not provide a survival advantage.

Local expression of interleukin-2 by B16 melanoma cells results in decreased tumour growth and long-term tumour dormancy

The tumour microenvironment is complex containing not only neoplastic cells but also a variety of host cells. The heterogeneous infiltrating immune cells include subsets of cells with opposing functions, whose activities are mediated either directly or through the cytokines they produce. Systemic delivery of cytokines such as interleukin-2 ( IL-2) has been used clinically to enhance anti-tumour responses, but these molecules are generally thought to have evolved to act locally in a paracrine fashion. In this study we examined the effect of local production of IL-2 on the growth and the immune response to B16 melanoma cells. We found that the local production of IL-2 enhances the number of interferon-γ-expressing CD8 T and natural killer cells in the tumour, as well as inducing expression of vascular cell adhesion molecule 1 on tumour vessels. These responses were largely absent in interferon-γ knockout mice. The expression of IL-2 in the tumour microenvironment decreases tumour growth despite also enhancing Foxp3(+)  CD4(+) regulatory T cells and anti-inflammatory cytokines such as IL-10. Higher levels of IL-2 in the tumour microenvironment eliminated the progressive growth of the B16 cells in vivo, and this inhibition was dependent on the presence of either T cells or, to a lesser extent, natural killer cells. Surprisingly however, the B16 tumours were not completely eliminated but instead were controlled for an extended period of time, suggesting that a form of tumour dormancy was established.

Inhibitory effects of the attenuated Salmonella typhimurium containing the IL-2 gene on hepatic tumors in mice

To observe the inhibitory effects of an attenuated S. typhimurium strain carrying IL-2 gene (TPI) on hepatoma cell line (HepG2) and transplanted tumors in mice. TPI, TPG (an attenuated S. typhimurium strain carrying green fluorescent protein gene), and TP (an attenuated S. typhimurium strain) strains were transfected into HepG2 cells. At 48h after transfecting, the transfection rate was 82.58 ± 1.74%. The expression level of IL-2 was (99.5 ± 12.2) ng/1 × 10⁶ cells. Compared with TPG, TP, and normal mouse groups, the proportion of CD4⁺ T and CD8⁺ T cells in the blood from the TPI group was higher, the levels of IgM and IgG₁ were significantly increased, and the proliferation activity of splenic lymphocyte was significantly stronger. The transplanted tumor weight in the TPI group was significantly smaller than that in the other two groups. The infiltration of lymphocytes increased in the tumor from TPI group mice. TPI was effectively transfected into cancer cells, which expressed the protein of interest. Oral administration of TPI prolonged survival of mice transplanted with hepatoma cell tumours.

Therapeutic antitumor efficacy of anti-epidermal growth factor receptor antibody, cetuximab, against malignant pleural mesothelioma

Epidermal growth factor receptor (EGFR) is commonly overexpressed in malignant pleural mesothelioma (MPM). Cetuximab is a chimeric mouse-human antibody targeted against EGFR and induces potent antibody-dependent cellular cytotoxicity (ADCC). The action of cetuximab against MPM cells has not been well studied. Therefore, in this study, we investigated the antitumor activity of cetuximab against MPM cell lines, particularly with respect to ADCC activity in vitro and in vivo. EGFR expression of MPM cells was measured by a quantitative flow cytometric analysis and immunohistochemistry. The effect of cetuximab on growth inhibition was assessed using a modified MTT assay. The ADCC activity was measured by a 4-h ⁵¹Cr release assay using fresh or IL-2-activated peripheral blood mononuclear cells. In vivo antitumor activity of cetuximab was evaluated using an orthotopic implantation mouse model. Cetuximab-mediated ADCC activity against MPM cells was observed at low concentration (0.25 mg/ml) and was enhanced by IL-2, whereas no direct effect on growth inhibition was detected. A logarithmic correlation was observed between the number of EGFRs on MPM cells and ADCC activity. Low EGFR expression on the MPM cells, which was weakly detectable by immunohistochemistry, was sufficient for maximum ADCC activity. In the mouse model, cetuximab treatment with or without IL-2 significantly inhibited intrathoracic tumor growth and prolonged their survival. Our study shows that cetuximab has potent anti-MPM activity both in vitro and in vivo, mainly through the immunologic mechanism of ADCC. Cetuximab has the potential to be used as a novel therapy for MPM patients.

In vitro assessment of choline dihydrogen phosphate (CDHP) as a vehicle for recombinant human interleukin-2 (rhIL-2)

Choline dihydrogen phosphate (CDHP) is an ionic liquid reported to increase thermal stability of model proteins. The current work investigated CDHP effect on structural integrity and biological activity of recombinant human interleukin-2 (rhIL-2), a therapeutic protein used for treating advanced melanoma. In vitro CDHP biocompatibility was also evaluated using primary cell cultures, or B16-F10 cell line, chronically exposed to the ionic liquid. Formulation of rhIL-2 in an aqueous 680mM CDHP pH 7.4 solution resulted in a 12.5°C increase in the T_m of rhIL-2 compared to a basic buffer formulation, and provided conformational rhIL-2 stabilization when the solution was heated to 23.3°C above the T_m. CDHP solutions (≤80mM), exhibited no cytotoxic activity toward primary splenocytes or B16-F10 cells in culture. However, a 10-fold loss in biological activity was observed when rhIL-2 was used in a 30mM CDHP aqueous solution with NaHCO₃ (pH≥7.2) compared to controls without CDHP. While increased T_m is associated with a diminished rhIL-2 biological activity, the therapeutic protein remains structurally intact and functional.

Preparation and evaluation of PLGA microparticles as carrier for the pulmonary delivery of rhIL-2 : I. Effects of some formulation parameters on microparticle characteristics

In this study, recombinant human interleukin-2 (rhIL-2) containing poly(lactic-co-glycolic acid) (PLGA) microparticles were prepared for pulmonary administration by modified w/o/w double emulsion solvent extraction method and the effects of various formulation parameters on the physicochemical properties of the microparticles were investigated. Microparticles in suitable size for pulmonary administration (4.02 µm) were obtained by increasing dichloromethane volume used in the organic phase. Also, a very high encapsulation efficiency (99.22%) value could be reached in these microparticles. In the sodium dodecyl sulphate-polyacrylamide gel electrophoresis analysis, rhIL-2 extracted from microparticles having a similar band with native rhIL-2 showed that the protein was not affected by the encapsulation process. The release curves of microparticles exhibited a biphasic fashion, characterized by a fast release phase at initial 1 day, followed by a slower one on the remaining days. Bioactivity investigations using T cells show that rhIL-2 encapsulated in PLGA microparticles retain their biological activity.

Experiment specific expression patterns

The differential analysis of genes between microarrays from several experimental conditions or treatments routinely estimates which genes change significantly between groups. As genes are never regulated individually, observed behavior may be a consequence of changes in other genes. Existing approaches like co-expression analysis aim to resolve such patterns from a wide range of experiments. The knowledge of such a background set of experiments can be used to compute expected gene behavior based on known links. It is particularly interesting to detect previously unseen specific effects in other experiments. Here, a new method to spot genes deviating from expected behavior (PAttern DEviation SCOring--Padesco) is devised. It uses linear regression models learned from a background set to arrive at gene specific prediction accuracy distributions. For a given experiment, it is then decided whether each gene is predicted better or worse than expected. This provides a novel way to estimate the experiment specificity of each gene. We propose a validation procedure to estimate the detection of such specific candidates and show that these can be identified with an average accuracy of about 85%.

The differential immunological activities of Ganoderma lucidum on human pre-cancerous uroepithelial cells

AIMS OF THE STUDY

Ganoderma lucidum is active to stimulate immunological effector cells, but the effects on uroepithelial cells have never been explored. The present study compared the expression of major cytokines induced by the water (GLw) and ethanol (GLe) extracts of G. lucidum.

MATERIALS AND METHODS

The pre-cancerous human uroepithelial cell (HUC-PC) line was employed. A total of 15 cytokines, including major Th1/Th2 cytokines and chemokines, were measured in the complete media after 24h incubation with GLw and GLe. Additionally, the following assays were performed: cytotoxicity, apoptosis, migration of neutrophils, and nuclear factor-kappaB (NF-κB) DNA binding activity.

RESULTS

GLe inhibited the growth of HUC-PC cells through apoptosis. Interleukins IL-2, IL-6, and IL-8 were significantly up-regulated by GLe in dose-dependent manners, but not by GLw. However, MCP-1 level was significantly increased by GLw but was oppositely reduced by GLe. Furthermore, the elevation of cytokine expression was correlated with the enhancement of p50/p65 NF-κB activity induced by GLe. The elevated IL-8 levels in GLe-treated cells were also correlated with the migration of neutrophils.

CONCLUSIONS

GLe and GLw exhibited different immunological activities on the HUC-PC cells. In particular, the activities of GLe may favor the clearance of high risk urothelial cells, suggesting potent chemopreventive ingredients are extractable by ethanol from G. lucidum.

Induction of potent anti-tumor responses while eliminating systemic side effects via liposome-anchored combinatorial immunotherapy

Immunostimulatory therapies that activate immune response pathways are of great interest for overcoming the immunosuppression present in advanced tumors. Agonistic anti-CD40 antibodies and CpG oligonucleotides have previously demonstrated potent, synergistic anti-tumor effects, but their clinical use even as monotherapies is hampered by dose-limiting inflammatory toxicity provoked upon systemic exposure. We hypothesized that by anchoring immuno-agonist compounds to lipid nanoparticles we could retain the bioactivity of therapeutics in the local tumor tissue and tumor-draining lymph node, but limit systemic exposure to these potent molecules. We prepared PEGylated liposomes bearing surface-conjugated anti-CD40 and CpG and assessed their therapeutic efficacy and systemic toxicity compared to soluble versions of the same immuno-agonists, injected intratumorally in the B16F10 murine model of melanoma. Anti-CD40/CpG-liposomes significantly inhibited tumor growth and induced a survival benefit similar to locally injected soluble anti-CD40 + CpG. Biodistribution analyses following local delivery showed that the liposomal carriers successfully sequestered anti-CD40 and CpG in vivo, reducing leakage into systemic circulation while allowing draining to the tumor-proximal lymph node. Contrary to locally-administered soluble immunotherapy, anti-CD40/CpG-liposomes did not elicit significant increases in serum levels of ALT enzyme, systemic inflammatory cytokines, or overall weight loss, confirming that off-target inflammatory effects had been minimized. The development of a delivery strategy capable of inducing robust anti-tumor responses concurrent with minimal systemic side effects is crucial for the continued progress of potent immunotherapies toward widespread clinical translation.

Development of an attenuated interleukin-2 fusion protein that can be activated by tumour-expressed proteases

The ability to alter the cytokine microenvironment has the potential to shape immune responses in many physiological settings, including the immunotherapy of tumours. We set out to develop a general approach in which cytokines could be functionally attenuated until activated. We report the development and initial characterization of fusion proteins in which human or mouse interleukin-2 (IL-2), a potent growth factor for immune cells, is joined to a specific IL-2 inhibitory binding component separated by a protease site. The rationale is that upon cleavage by a protease the cytokine is free to dissociate from the inhibitory component and becomes biologically more available. We describe the successful development of two attenuation strategies using specific binding: the first uses the mouse IL-2 receptor alpha chain as the inhibitory binding component whereas the second employs a human antibody fragment (scFv) reactive with human IL-2. We demonstrated that the fusion proteins containing a prostate-specific antigen or a matrix metalloproteinase (MMP) protease cleavage site are markedly attenuated in the intact fusion protein but had enhanced bioactivity of IL-2 in vitro when cleaved. Further, we showed that a fusion protein composed of the IL-2/IL-2 receptor alpha chain with an MMP cleavage site reduced tumour growth in vivo in a peritoneal mouse tumour model. This general strategy should be applicable to other proteases and immune modulators allowing site-specific activation of immunomodulators while reducing unwanted side-effects.

Intratumoral interleukin-21 increases antitumor immunity, tumor-infiltrating CD8+ T-cell density and activity, and enlarges draining lymph nodes

Interleukin (IL)-21 is a novel cytokine in clinical development for the treatment of cancer. In this study, we have compared the efficacy of subcutaneous and intratumoral (IT) administration of IL-21 protein in two syngeneic mouse tumor models, RenCa renal cell carcinoma and B16 melanoma, and investigated the mechanisms by which IL-21 enhances CD8 T-cell-mediated antitumor immunity. We found that in comparison to subcutaneous administration, IT administration of IL-21 more potently inhibited tumor growth and increased survival. This correlated with increased densities of tumor-infiltrating CD8 and CD4CD25 T cells, but not CD4CD25FoxP3 T cells. Furthermore, IT administration of IL-21 increased degranulation, and expression of interferon-gamma and granzyme B in tumor-infiltrating CD8 T cells. Tumors injected with IL-21 grew slower than contralateral tumors, suggesting that the increased efficacy of IT administration of IL-21 was due to a local rather than systemic effect. IT administration of IL-21 led to enlarged tumor-draining lymph nodes (LNs), with increased naive lymphocyte numbers and proliferation of activated lymphocytes, suggesting that local administration of IL-21 generally benefits the tumor microenvironment and activates tumor-draining LNs. Overall, our data suggest that IL-21 augments CD8 T-cell-mediated antitumor immunity through increased proliferation and effector function and acts both on tumor-infiltrating CD8 T cells as well as on the draining LNs. IT administration led to superior CD8 T-cell proliferation, effector function, and antitumor efficacy, suggesting that IT administration of IL-21 may be clinically useful in patients with unresectable tumors.

"First do no harm" and the importance of prediction in oncology

Present cancer treatment strategies are based on the assumption that a therapy may work (“response”) or not work (“no-response”). However, the existing evidence suggests that current cancer treatment modalities may also have a cancer-promoting effect in part of the patients. In this paper, some relevant data are reviewed suggesting that surgery, irradiation, chemotherapy and immunotherapy can stimulate tumor growth / metastatic spread and decrease survival of patients in certain subgroups. Thus, results of cancer treatment may be improved by detection and use of biomarkers that correlate with positive or negative therapeutic effects. Small trials based on groups with differing biomarkers rather than large phase III trials may aid the development and efficacy testing of new anticancer drugs. Moreover, ignoring biomarkers that correlate with positive or negative therapeutic effect may not be compatible anymore with the ethical principle “First Do No Harm”.

Direct and indirect antitumor effects by human peripheral blood lymphocytes expressing both chimeric immune receptor and interleukin-2 in ovarian cancer xenograft model

Human peripheral blood lymphocytes (PBLs) electroporated with RNA encoding anti-Her-2/neu-specific chimeric immune receptor (CIR) have been reported to elicit potent immune responses against SKOV3 tumors in a nude mouse model. However, CIR-electroporated PBL (CIR-PBL) did not proliferate, and the cell number rapidly decreased in the absence of exogenous interleukin-2 (IL-2). In this study, PBLs electroporated with both CIR and IL-2 RNA (CIR/IL-2-PBL) were studied to determine whether antitumor effects could be improved by adoptive immunotherapy. CIR and IL-2 were expressed in CIR/IL-2-PBL at levels similar to PBLs electroporated, with IL-2 RNA (IL-2-PBL) or CIR-PBL. Transfer of IL-2 RNA induced proliferation and prolonged survival of PBLs in vitro. In a xenograft model, both IL-2-PBL and CIR/IL-2-PBL showed significantly higher antitumor effects than CIR-PBL. The number of tumor-infiltrating natural killer (NK) cells was significantly increased in IL-2-PBL and CIR/IL-2-PBL. After NK cell depletion, IL-2-PBL showed significantly lower antitumor effects than CIR/IL-2-PBL. These results suggest that transfer of IL-2 RNA to CIR-PBL can promote NK cell infiltration of tumors and prolong survival of infused PBLs in vivo. RNA electroporated PBLs may represent efficient tools for delivery of functional molecules to tumors by multiple gene transfer.

Treatment with interleukin-2 in malignant pleural mesothelioma: immunological and angiogenetic assessment and prognostic impact

Background:

Administration of interleukin-2 (IL-2) has shown some effects on malignant pleural mesothelioma (MPM) tumour regression. The purpose of this study was to investigate the ability of IL-2 to modify immunological effector cells and angiogenesis in MPM patients and their prognostic value.

Methods:

Tumour-infiltrating lymphocytes (CD4, CD8, Foxp3), mast cells (MCs) (tryptase and chymase), microvessel count (MVC) and VEGF were determined by immunohistochemistry in two series of MPM patients: 60 patients treated with intra-pleural preoperative IL-2 and 33 patients untreated.

Results:

Tryptase MCs, and CD8 and Foxp3 lymphocytes were significantly increased in the IL-2-treated group, whereas MVC was significantly lower in the same group. Moreover, in the IL-2-treated group, greater tryptase+MCs and greater Foxp3 lymphocytes were associated with improved and poorer clinical outcomes, respectively. Notably, when these two immunological parameters were combined, they predicted outcomes more effectively.

Conclusions:

This study showed that IL-2 treatment leads to a significant increase of immunological parameters, concomitantly with a reduction in vasculature, providing new insight into the cancer mechanisms mediated by IL-2. Moreover, these results suggest that tryptase-positive MCs and Foxp3+ lymphocytes predict clinical outcomes in IL-2-treated patients, highlighting the critical role of the inflammatory response in mesothelioma cancer progression.

Tryptase mast cells in malignant pleural mesothelioma as an independent favorable prognostic factor

INTRODUCTION

Malignant pleural mesothelioma is a highly aggressive neoplasm with an incidence that is increasing world-wide. Mast cells are part of the innate immune system and have been associated with different solid tumors, but there is controversy surrounding their pro- and antitumorigenic effects in cancers. There are two subsets of human mast cells, resulting from the expression of different enzymes: tryptase positive mast cells and chymase positive mast cells. The purpose of this study was to determine the presence and prognostic significance of tumor infiltrating mast cells in mesothelioma.

METHODS

Tryptase and chymase mast cell counts were determined by immunohistochemistry in 60 patients with mesothelioma. All pathologic samples were from patients who underwent treatment with intrapleural preoperative interleukin-2 (18 x 10(6) IU/d for 3 days). After one day of recovery, patients underwent surgery. Pleural samples were also immunostained for CD34 to evaluate microvessel count.

RESULTS

High tryptase mast cells counts were found in the majority (73.3%) of the cases studied, and the results were significantly associated with both overall survival (p = 0.02) and time to progression (p = 0.01). This finding was confirmed using multivariate analysis: a higher tryptase mast cells count emerged as an independent favorable prognostic factor (p = 0.02). However, tryptase mast cells count did not show significant correlation with microvessel count.

CONCLUSIONS

These results suggest that tumor infiltrating tryptase mast cells, after interleukin-2 preoperative induction therapy, predict improved clinical outcome in patients with malignant pleural mesothelioma, and highlight the critical role of the local inflammatory response in mesothelioma cancer progression.