Novel immunocytokine IL12-SS1 (Fv) inhibits mesothelioma tumor growth in nude mice

Interleukin-12 in multimodal tumor therapies for induction of anti-tumor immunity

Interleukin-12 (IL-12) can be used as an immunomodulator in cancer immunotherapy. And it has demonstrated enormous potential in inhibiting tumor growth and improving the tumor microenvironment (TME) by several preclinical models. However, some disappointing results have showed in the early clinical trials when IL-12 used as a single agent for systemic cancer therapy. Combination therapy is an effective way to significantly fulfill the great potential of IL-12 as an immunomodulator. Here, we discuss the effects of IL-12 combined with traditional methods (chemotherapy, radiotherapy and surgery), targeted therapy or immunotherapy in the preclinical and clinical studies. Moreover, we summarized the potential mechanism underlying the anti-tumor effect of IL-12 in the combination strategies. And we also discussed the delivery methods and tumor-targeted modification of IL-12 and outlines future prospects for IL-12 as an immunomodulator.

Preclinical assessment of a novel human antibody VH domain targeting mesothelin as an antibody-drug conjugate

Mesothelin (MSLN) has been a validated tumor-associated antigen target for several solid tumors for over a decade, making it an attractive option for therapeutic interventions. Novel antibodies with high affinity and better therapeutic properties are needed. In the current study, we have isolated and characterized a novel heavy chain variable (VH) domain 3C9 from a large-size human immunoglobulin VH domain library. 3C9 exhibited high affinity (KD [dissociation constant] <3 nM) and binding specificity in a membrane proteome array (MPA). In a mouse xenograft model, 3C9 fused to human IgG1 Fc was detected at tumor sites as early as 8 h post-infusion and remained at the site for over 10 days. Furthermore, 3C9 fused to a human Fc domain drug conjugate effectively inhibited MSLN-positive tumor growth in a mouse xenograft model. The X-ray crystal structure of full-length MSLN in complex with 3C9 reveals interaction of the 3C9 domains with two distinctive residue patches on the MSLN surface. This newly discovered VH antibody domain has a high potential as a therapeutic candidate for MSLN-expressing cancers.

High Homogeneity of Mesothelin Expression in Primary and Metastatic Ovarian Cancer

To study the extent of heterogeneity of mesothelin overexpression in primary ovarian cancers and their peritoneal and lymph node metastases, a tissue microarray (TMA) was constructed from multiple sites of 220 ovarian cancers and analyzed by immunohistochemistry. One tissue core each was taken from up to 18 different tumor blocks per cancer, resulting in a total of 2460 tissue spots from 423 tumor sites (188 primary cancers, 162 peritoneal carcinosis, and 73 lymph node metastases). Positive mesothelin expression was found in 2041 of the 2342 (87%) arrayed tissue spots and in 372 of the 392 (95%) tumor sites that were interpretable for mesothelin immunohistochemistry. Intratumoral heterogeneity was found in 23% of 168 primary cancer sites interpretable for mesothelin and decreased to 12% in 154 peritoneal carcinosis and to 6% in 71 lymph node metastases ( P <0.0001). Heterogeneity between the primary tumor and matched peritoneal carcinosis was found in 16% of 102 cancers with interpretable mesothelin results. In these cancers, the mesothelin status switched from positive in the primary tumor to negative in the peritoneal carcinosis (3 cancers) in or vice versa (2 cancers), or a mixture of positive and negative peritoneal carcinoses was found (11 cancers). No such switch was seen between the mesothelin-interpretable primary tumors and their nodal metastases of 59 cancers, and only 1 mesothelin-positive tumor had a mixture of positive and negative lymph node metastases. In conclusion, mesothelin expression is frequent and highly homogeneous in ovarian cancer.

Engineering interferons and interleukins for cancer immunotherapy

Cytokines are a class of potent immunoregulatory proteins that are secreted in response to various stimuli and act locally to regulate many aspects of human physiology and disease. Cytokines play important roles in cancer initiation, progression, and elimination, and thus, there is a long clinical history associated with the use of recombinant cytokines to treat cancer. However, the use of cytokines as therapeutics has been limited by cytokine pleiotropy, complex biology, poor drug-like properties, and severe dose-limiting toxicities. Nevertheless, cytokines are crucial mediators of innate and adaptive antitumor immunity and have the potential to enhance immunotherapeutic approaches to treat cancer. Development of immune checkpoint inhibitors and combination immunotherapies has reinvigorated interest in cytokines as therapeutics, and a variety of engineering approaches are emerging to improve the safety and effectiveness of cytokine immunotherapy. In this review we highlight recent advances in cytokine biology and engineering for cancer immunotherapy.

Mesothelin is Commonly Expressed in Pancreatic Adenocarcinoma but Unrelated to Cancer Aggressiveness

Data on Mesothelin (MSLN) expression in human normal and cancerous tissues is controversial. We employed immunohistochemistry (IHC) on a tissue microarray (TMA) from 599 pancreatic cancers and 12 large tissue sections of pancreatitis. MSLN expression was highest in pancreatic adenocarcinomas (89%) and adenocarcinomas of the ampulla Vateri (79%), infrequent in pancreatitis and absent in 6 acinus cell carcinomas and normal pancreas. MSLN expression was unrelated to pathological tumor stage, grade, metastasis, and tumor-infiltrating CD8+ lymphocytes. In conclusion, pancreatic cancer may be ideally suited for putative anti- MSLN therapies, and MSLN may represent a suitable biomarker for pancreatic cancer diagnosis, especially on small biopsies.

Immunoengineering approaches for cytokine therapy

Since the discovery of cytokines, much effort has been put forth to achieve therapeutic translation for treatment of various diseases, including cancer and autoimmune diseases. Despite these efforts, very few cytokines have cleared regulatory approval, and those that were approved are not commonly used due to their challenging toxicity profile and/or limited therapeutic efficacy. The main limitation in translation has been that wild-type cytokines have unfavorable pharmacokinetic and pharmacodynamic profiles, either eliciting unwanted systemic side effects or insufficient residence in secondary lymphoid organs. In this review, we address protein-engineering approaches that have been applied to both proinflammatory and anti-inflammatory cytokines to enhance their therapeutic indices, and we highlight diseases in which administration of engineered cytokines is especially relevant.

Mesothelin Expression in Human Tumors: A Tissue Microarray Study on 12,679 Tumors

Mesothelin (MSLN) represents an attractive molecule for targeted cancer therapies. To identify tumors that might benefit from such therapies, tissue microarrays including 15,050 tumors from 122 different tumor types and 76 healthy organs were analyzed for MSLN expression by immunohistochemistry. Sixty-six (54%) tumor types showed at least occasional weak staining, including 50 (41%) tumor types with at least one strongly positive sample. Highest prevalence of MSLN positivity had ovarian carcinomas (serous 97%, clear cell 83%, endometrioid 77%, mucinous 71%, carcinosarcoma 65%), pancreatic adenocarcinoma (ductal 75%, ampullary 81%), endometrial carcinomas (clear cell 71%, serous 57%, carcinosarcoma 50%, endometrioid 45%), malignant mesothelioma (69%), and adenocarcinoma of the lung (55%). MSLN was rare in cancers of the breast (7% of 1138), kidney (7% of 807), thyroid gland (1% of 638), soft tissues (0.3% of 931), and prostate (0 of 481). High expression was linked to advanced pathological tumor (pT) stage (p < 0.0001) and metastasis (p < 0.0001) in 1619 colorectal adenocarcinomas, but unrelated to parameters of malignancy in 1072 breast-, 386 ovarian-, 174 lung-, 757 kidney-, 171 endometrial-, 373 gastric-, and 925 bladder carcinomas. In summary, numerous important cancer types with high-level MSLN expression might benefit from future anti-MSLN therapies, but MSLN’s prognostic relevance appears to be limited.

Antitumor effect of IL-12 gene-modified bone marrow mesenchymal stem cells combined with Fuzheng Yiliu decoction in an in vivo glioma nude mouse model

BACKGROUND

Glioma is a complex cancer with a high morbidity and high mortality. Bone marrow mesenchymal stem cells (BMSCs) have shown promise as an excellent cell/drug delivery vehicle for gene-targeted therapy; however, maintaining genetic stability and biological activity remains difficult. Furthermore, whether BMSCs support or inhibit tumor growth remains debated. This study investigated whether a traditional Chinese medicine fomular, Fuzheng Yiliu decoction (FYD) had a synergistic antitumor effect with IL-12 gene-modified BMSCs in glioma-bearing nude mice METHODS: The lentivirus-mediated IL-12 gene was transfected into primarily cultured BMSCs. A total of 72 BALB/c nude mice were used to establish xenograft models with glioma U251 cells and were divided into groups (n = 12) including blank control group, nude mouse model group (model group), lentiviral transfection of BMSC group with no gene loading (BMSC group), IL-12 lentivirus-transfected BMSC group (IL-12 + BMSC group), FYD treatment group (FYD group), and FYD treatment in IL-12 lentivirus-transfected BMSC group (FYD + IL-12 + BMSC group).. After treatment for 14 days, all mice were sacrificed to collect tumor tissue and serum for more detection, such as distribution of BMSCs, cell apoptosis in xenograft tumors, serum IL-12 and INF-γ levels, mouse weight and tumor volume were measured RESULTS: There were significantly more apoptotic cells in tumor tissue in IL-12 gene transfected group, FYD treatment group and FYD combining with IL-12 gene transfected group than that in the model group (P < 0.05). The FYD + IL-12 + BMSC group showed significantly higher Bax and lower Bcl-2 expression (P < 0.05), and serum IL-12 and INF-γ levels (P < 0.05) were higher than that in all other groups. After the intervention, this group also showed a strong inhibitory effect against tumor growth (P < 0.05) CONCLUSIONS: This study suggested FYD treatment combined with IL-12 gene-modified BMSCs shows synergistic antitumor effect in glioma-bearing nude mice.

Localized Interleukin-12 for Cancer Immunotherapy

Interleukin-12 (IL-12) is a potent, pro-inflammatory type 1 cytokine that has long been studied as a potential immunotherapy for cancer. Unfortunately, IL-12's remarkable antitumor efficacy in preclinical models has yet to be replicated in humans. Early clinical trials in the mid-1990's showed that systemic delivery of IL-12 incurred dose-limiting toxicities. Nevertheless, IL-12's pleiotropic activity, i.e., its ability to engage multiple effector mechanisms and reverse tumor-induced immunosuppression, continues to entice cancer researchers. The development of strategies which maximize IL-12 delivery to the tumor microenvironment while minimizing systemic exposure are of increasing interest. Diverse IL-12 delivery systems, from immunocytokine fusions to polymeric nanoparticles, have demonstrated robust antitumor immunity with reduced adverse events in preclinical studies. Several localized IL-12 delivery approaches have recently reached the clinical stage with several more at the precipice of translation. Taken together, localized delivery systems are supporting an IL-12 renaissance which may finally allow this potent cytokine to fulfill its considerable clinical potential. This review begins with a brief historical account of cytokine monotherapies and describes how IL-12 went from promising new cure to ostracized black sheep following multiple on-study deaths. The bulk of this comprehensive review focuses on developments in diverse localized delivery strategies for IL-12-based cancer immunotherapies. Advantages and limitations of different delivery technologies are highlighted. Finally, perspectives on how IL-12-based immunotherapies may be utilized for widespread clinical application in the very near future are offered.

Malignant peritoneal mesothelioma: clinical aspects, and therapeutic perspectives

Malignant peritoneal mesothelioma (MPM) is a rare disease with a wide clinical spectrum. It arises from the peritoneal lining and commonly presents with diffuse, extensive spread throughout the abdomen and, more rarely, metastatic spread beyond the abdominal cavity. Computed tomography, magnetic resonance imaging and positron-emission tomography are important diagnostic tools used for the preoperative staging of MPM. The definitive diagnosis is based on histopathological analysis, mainly via immunohistochemistry. In this regard, paired-box gene 8 negativity represents a useful diagnostic biomarker for differentiating MPM from ovarian carcinoma. In addition, BRCA1-associated protein-1 (BAP1) loss is specific to MPM and allows it to be distinguished from both benign mesothelial lesions and ovarian serous tumors. Cytoreductive surgery (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) has become an increasingly important therapeutic approach, while systemic therapies are still being developed. Histology, Ki-67, completeness of cytoreduction, age, sex, and baseline thrombocytosis are commonly used to optimize patient selection for CRS with HIPEC. Additionally, it is well recognized that, compared to other subtypes, an epithelial morphology is associated with a favorable prognosis, whereas baseline thrombocytosis predicts an aggressive biologicalbehavior. Platelets and other immunologic cytokines have been evaluated as potential novel therapeutic targets. Epigenetic modifiers, including BAP1, SETD2 and DDX3X, are crucial in mesothelial tumorigenesis and provide opportunities for targeted treatment. Overexpression of the closely interacting phosphoinositide 3-kinase (PI3K) and the mammalian target of rapamycin (mTOR) pathways appears crucial in regulation of the malignant phenotype. The use of targeted therapies with PI3K-mTOR-based inhibitors requires further clinical assessment as a novel approach.

Evolution of the magic bullet: Single chain antibody fragments for the targeted delivery of immunomodulatory proteins

Immunocytokines are fusion proteins that combine the specific antigen binding capacities of an antibody or derivative thereof and the potent bioactivity of a cytokine partner. These novel biopharmaceuticals have been directed to various targets of oncological as well as non-oncological origin and a handful of promising constructs are currently advancing in the clinical trial pipeline. Several factors such as the choice of a disease specific antigen, the antibody format and the modulatory nature of the payload are crucial, not only for therapeutic efficacy and safety but also for the commercial success of such a product. In this review, we provide an overview of the basic principles and obstacles in immunocytokine design with a specific focus on single chain antibody fragment-based constructs that employ interleukins as the immunoactive component. Impact statement Selective activation of the immune system in a variety of malignancies represents an attractive approach when existing strategies have failed to provide adequate treatment options. Immunocytokines as a novel class of bifunctional protein therapeutics have emerged recently and generated promising results in preclinical and clinical studies. In order to harness their full potential, multiple different aspects have to be taken into consideration. Several key points of these fusion constructs are discussed here and should provide an outline for the development of novel products based on an overview of selected formats.

Immunocytokines and bispecific antibodies: two complementary strategies for the selective activation of immune cells at the tumor site

The activation of the immune system for a selective removal of tumor cells represents an attractive strategy for the treatment of metastatic malignancies, which cannot be cured by existing methodologies. In this review, we examine the design and therapeutic potential of immunocytokines and bispecific antibodies, two classes of bifunctional products which can selectively activate the immune system at the tumor site. Certain protein engineering aspects, such as the choice of the antibody format, are common to both classes of therapeutic agents and can have a profound impact on tumor homing performance in vivo of individual products. However, immunocytokines and bispecific antibodies display different mechanisms of action. Future research activities will reveal whether an additive of even synergistic benefit can be obtained from the judicious combination of these two types of biopharmaceutical agents.

Insight to drug delivery aspects for colorectal cancer

Colorectal cancer (CRC) is the third most common cancer diagnosed worldwide in human beings. Surgery, chemotherapy, radiotherapy and targeted therapies are the conventional four approaches which are currently used for the treatment of CRC. The site specific delivery of chemotherapeutics to their site of action would increase effectiveness with reducing side effects. Targeted oral drug delivery systems based on polysaccharides are being investigated to target and deliver chemotherapeutic and chemopreventive agents directly to colon and rectum. Site-specific drug delivery to colon increases its concentration at the target site, and thus requires a lower dose and hence abridged side effects. Some novel therapies are also briefly discussed in article such as receptor (epidermal growth factor receptor, folate receptor, wheat germ agglutinin, VEGF receptor, hyaluronic acid receptor) based targeting therapy; colon targeted proapoptotic anticancer drug delivery system, gene therapy. Even though good treatment options are available for CRC, the ultimate therapeutic approach is to avert the incidence of CRC. It was also found that CRCs could be prevented by diet and nutrition such as calcium, vitamin D, curcumin, quercetin and fish oil supplements. Immunotherapy and vaccination are used nowadays which are showing better results against CRC.

Latest developments in our understanding of the pathogenesis of mesothelioma and the design of targeted therapies

Malignant mesothelioma is an aggressive cancer whose pathogenesis is causally linked to occupational exposure to asbestos. Familial clusters of mesotheliomas have been observed in settings of genetic predisposition. Mesothelioma incidence is anticipated to increase worldwide in the next two decades. Novel treatments are needed, as current treatment modalities may improve the quality of life, but have shown modest effects in improving overall survival. Increasing knowledge on the molecular characteristics of mesothelioma has led to the development of novel potential therapeutic strategies, including: molecular targeted approaches, that is the inhibition of vascular endothelial growth factor with bevacizumab; immunotherapy with chimeric monoclonal antibody, immunotoxin, antibody drug conjugate, vaccine and viruses; inhibition of asbestos-induced inflammation, that is aspirin inhibition of HMGB1 activity may decrease or delay mesothelioma onset and/or growth. We elaborate on the rationale behind new therapeutic strategies, and summarize available preclinical and clinical results, as well as efforts still ongoing.

Immunotoxin targeting glypican-3 regresses liver cancer via dual inhibition of Wnt signalling and protein synthesis

Glypican-3 is a cell surface glycoprotein that associates with Wnt in liver cancer. We develop two antibodies targeting glypican-3, HN3 and YP7. The first antibody recognizes a functional epitope and inhibits Wnt signalling, whereas the second antibody recognizes a C-terminal epitope but does not inhibit Wnt signalling. Both are fused to a fragment of Pseudomonas exotoxin A (PE38) to create immunotoxins. Interestingly, the immunotoxin based on HN3 (HN3-PE38) has superior antitumor activity as compared with YP7 (YP7-PE38) both in vitro and in vivo. Intravenous administration of HN3-PE38 alone, or in combination with chemotherapy, induces regression of Hep3B and HepG2 liver tumour xenografts in mice. This study establishes glypican-3 as a promising candidate for immunotoxin-based liver cancer therapy. Our results demonstrate immunotoxin-induced tumour regression via dual mechanisms: inactivation of cancer signalling via the antibody and inhibition of protein synthesis via the toxin.

Advances in the management of peritoneal mesothelioma

Malignant peritoneal mesothelioma (PM) is an infrequent disease which has historically been associated with a poor prognosis. Given its long latency period and non-specific symptomatology, a diagnosis of PM can be suggested by occupational exposure history, but ultimately relies heavily on imaging and diagnostic biopsy. Early treatment options including palliative operative debulking, intraperitoneal chemotherapy, and systemic chemotherapy have marginally improved the natural course of the disease with median survival being approximately one year. The advent of cytoreduction (CRS) with hyperthermic intraperitoneal chemotherapy (HIPEC) has dramatically improved survival outcomes with wide median survival estimates between 2.5 to 9 years; these studies however remain largely heterogeneous, with differing study populations, tumor biology, and specific treatment regimens. More recent investigations have explored extent of cytoreduction, repeated operative intervention, and choice of chemotherapy but have been unable to offer definitive conclusions. CRS and HIPEC remain morbid procedures with complication rates ranging between 30% to 46% in larger series. Accordingly, an increasing interest in identifying molecular targets and developing targeted therapies is emerging. Among such novel targets is sphingosine kinase 1 (SphK1) which regulates the production of sphingosine-1-phosphate, a biologically active lipid implicated in various cancers including malignant mesothelioma. The known action of specific SphK inhibitors may warrant further exploration in peritoneal disease.

Diagnosis and treatment of malignant pleural mesothelioma

There are three major challenges in the diagnosis of malignant pleural mesothelioma: mesothelioma must be distinguished from benign mesothelial hyperplasia; malignant mesothelioma (and its subtypes) must be distinguished from metastatic carcinoma; and invasion of structures adjacent to the pleura must be demonstrated. The basis for clarifying the first two aspects is determination of a panel of monoclonal antibodies with appropriate immunohistochemical evaluation performed by highly qualified experts. Clarification of the third aspect requires sufficiently abundant, deep biopsy material, for which thoracoscopy is the technique of choice. Video-assisted needle biopsy with real-time imaging can be of great assistance when there is diffuse nodal thickening and scant or absent effusion. Given the difficulties of reaching an early diagnosis, cure is not generally achieved with radical surgery (pleuropneumonectomy), so liberation of the tumor mass with pleurectomy/decortication combined with chemo- or radiation therapy (multimodal treatment) has been gaining followers in recent years. In cases in which surgery is not feasible, chemotherapy (a combination of pemetrexed and platinum-derived compounds, in most cases) with pleurodesis or a tunneled pleural drainage catheter, if control of pleural effusion is required, can be considered. Radiation therapy is reserved for treatment of pain associated with infiltration of the chest wall or any other neighboring structure. In any case, comprehensive support treatment for pain control in specialist units is essential: this acquires particular significance in this type of malignancy.

Immune therapies for malignant mesothelioma

Malignant mesothelioma (MM) is a rare disease which can develop in pleura, pericardium or peritoneum and in which the therapies available have limited efficacy and are associated with various side effects. Therefore, there is a need for more targeted and more effective therapies which are able to halt the disease progression. Among them immune therapies actively or passively directed against various structures of the MM cells seem to be particularly promising given their inhibitory potential demonstrated in both experimental and early clinical studies. Mesothelin in particular seem to be not only a biomarker of disease activity but also a therapeutic target. This review discusses the immune therapies currently investigated for MM.