Myeloid cell signatures in tumor microenvironment predicts therapeutic response in cancer

Relevance of Thymic Stromal Lymphopoietin on the Pathogenesis of Glioblastoma: Role of the Neutrophil

Glioblastoma multiforme (GBM) is the most predominant and malignant primary brain tumor in adults. Thymic stromal lymphopoietin (TSLP), a cytokine primarily generated by activated epithelial cells, has recently garnered attention in cancer research. This study was aimed to elucidate the significance of TSLP in GBM cells and its interplay with the immune system, particularly focused on granulocyte neutrophils. Our results demonstrate that the tumor produces TSLP when stimulated with epidermal growth factor (EGF) in both the U251 cell line and the GBM biopsy (GBM-b). The relevance of the TSLP function was evaluated using a 3D spheroid model. Spheroids exhibited increased diameter, volume, and proliferation. In addition, TSLP promoted the generation of satellites surrounding the main spheroids and inhibited apoptosis in U251 treated with temozolomide (TMZ). Additionally, the co-culture of polymorphonuclear (PMN) cells from healthy donors with the U251 cell line in the presence of TSLP showed a reduction in apoptosis and an increase in IL-8 production. TSLP directly inhibited apoptosis in PMN from GBM patients (PMN-p). Interestingly, the vascular endothelial growth factor (VEGF) production was elevated in PMN-p compared with PMN from healthy donors. Under these conditions, TSLP also increased VEGF production, in PMN from healthy donors. Moreover, TSLP upregulated programed death-ligand 1 (PDL-1) expression in PMN cultured with U251. On the other hand, according to our results, the analysis of RNA-seq datasets from Illumina HiSeq 2000 sequencing platform performed with TIMER2.0 webserver demonstrated that the combination of TSLP with neutrophils decreases the survival of the patient. In conclusion, our results position TSLP as a possible new growth factor in GBM and indicate its modulation of the tumor microenvironment, particularly through its interaction with PMN.

Myeloid-Derived Suppressor Cells in Solid Tumors

Myeloid-derived suppressor cells (MDSCs) are one of the main suppressive cell population of the immune system. They play a pivotal role in the establishment of the tumor microenvironment (TME). In the context of cancers or other pathological conditions, MDSCs can differentiate, expand, and migrate in large quantities during circulation, inhibiting the cytotoxic functions of T cells and NK cells. This process is regulated by ROS, iNOS/NO, arginase-1, and multiple soluble cytokines. The definition of MDSCs and their phenotypes in humans are not as well represented as in other organisms such as mice, owing to the absence of the cognate molecule. However, a comprehensive understanding of the differences between different species and subsets will be beneficial for clarifying the immunosuppressive properties and potential clinical values of these cells during tumor progression. Recently, experimental evidence and clinical investigations have demonstrated that MDSCs have a close relationship with poor prognosis and drug resistance, which is considered to be a leading marker for practical applications and therapeutic methods. In this review, we summarize the remarkable position of MDSCs in solid tumors, explain their classifications in different models, and introduce new treatment approaches to target MDSCs to better understand the advancement of new approaches to cancer treatment.

Changes in the tumor microenvironment and outcome for TME-targeting therapy in glioblastoma: A pilot study

Glioblastoma (GBM) is a hypervascular and aggressive primary malignant tumor of the central nervous system. Recent investigations showed that traditional therapies along with antiangiogenic therapies failed due to the development of post-therapy resistance and recurrence. Previous investigations showed that there were changes in the cellular and metabolic compositions in the tumor microenvironment (TME). It can be said that tumor cell-directed therapies are ineffective and rethinking is needed how to treat GBM. It is hypothesized that the composition of TME-associated cells will be different based on the therapy and therapeutic agents, and TME-targeting therapy will be better to decrease recurrence and improve survival. Therefore, the purpose of this study is to determine the changes in the TME in respect of T-cell population, M1 and M2 macrophage polarization status, and MDSC population following different treatments in a syngeneic model of GBM. In addition to these parameters, tumor growth and survival were also studied following different treatments. The results showed that changes in the TME-associated cells were dependent on the therapeutic agents, and the TME-targeting therapy improved the survival of the GBM bearing animals. The current GBM therapies should be revisited to add agents to prevent the accumulation of bone marrow-derived cells in the TME or to prevent the effect of immune-suppressive myeloid cells in causing alternative neovascularization, the revival of glioma stem cells, and recurrence. Instead of concurrent therapy, a sequential strategy would be better to target TME-associated cells.

The thromboprotective effect of traditional Chinese medicine Tongji 2 granules is dependent on anti-inflammatory activity by suppression of NF-κB pathways

Inflammation is a vital physiological response of the immune system meant to protect against the invasion of pathogens. However, accumulating evidence describes an intimate link between inflammation and thrombosis and cellular elements of the immune system of the immune system such as neutrophils and monocytes/macrophages are emerging as key players in the generation of a prothrombotic milieu suggesting that anti-inflammatory therapy may have a role in the management of thrombosis that is driven by inflammation. Tongji 2 (TJ2) is a traditional Chinese medication manufactured as granules by Tongji hospital of Tongji University (Shanghai, China) with known anti-inflammatory properties. In this study, we examine the effects of TJ2 on inflammation and thrombosis. Our study shows that TJ2 modulates NF-κB activation and thus generates a prominent anti-inflammatory effect. Further, we use mouse models of thrombosis to demonstrate that TJ2 has a beneficial effect in both arterial and venous thrombosis that occurs in the absence of alterations in platelet activation or coagulation.

Characterization of somatic mutation-associated microenvironment signatures in acute myeloid leukemia patients based on TCGA analysis

Recurrent genetic mutations occur in acute myeloid leukemia (AML) and have been incorporated into risk stratification to predict the prognoses of AML patients. The bone marrow microenvironment plays a critical role in the development and progression of AML. However, the characteristics of the genetic mutation-associated microenvironment have not been comprehensively identified to date. In this study, we obtained the gene expression profiles of 173 AML patients from The Cancer Genome Atlas (TCGA) database and calculated their immune and stromal scores by applying the ESTIMATE algorithm. Immune scores were significantly associated with OS and cytogenetic risk. Next, we categorized the intermediate and poor cytogenetic risk patients into individual-mutation and wild-type groups according to RUNX1, ASXL1, TP53, FLT3-ITD, NPM1 and biallelic CEBPA mutation status. The relationships between the immune microenvironment and each genetic mutation were investigated by identifying differentially expressed genes (DEGs) and conducting functional enrichment analyses of them. Significant immune- and stromal-relevant DEGs associated with each mutation were identified, and most of the DEGs (from the FLT3-ITD, NPM1 and biallelic CEBPA mutation groups) were validated in the GSE14468 cohort downloaded from the Gene Expression Omnibus (GEO) database. In summary, we identified key immune- and stromal-relevant gene signatures associated with genetic mutations in AML, which may provide new biomarkers for risk stratification and personalized immunotherapy.

Targeting IFN/STAT1 Pathway as a Promising Strategy to Overcome Radioresistance

The interferon (IFN)-mediated activation of the Janus kinase (JAK)-signal transducer and activator of transcription 1 (STAT1) signaling is crucial for cell sensitivity to ionizing radiation. Several preclinical studies have reported that the IFN/STAT1 pathway mediates radioresistance in the tumor microenvironment by shielding the immune responses and activating survival signaling pathways. This review focuses on the oncogenic function of the IFN/STAT1 pathway, emphasizing the major signaling pathway in radiation sensitization. Furthermore, it highlights the possibility of mediatory roles of the IFN/STAT1 pathway as a prognostic therapeutic target in the modulation of resistance to radiotherapy and chemotherapy. MicroRNA involved in the regulation of the IFN/STAT1 pathway is also discussed. A better understanding of radiation-induced IFN/STAT1 signaling will open new opportunities for the development of novel therapeutic strategies, as well as define new approaches to enhance radio-immunotherapy efficacy in the treatment of various types of cancers.

A Novel Bivalent Mannosylated Targeting Ligand Displayed on Nanoparticles Selectively Targets Anti-Inflammatory M2 Macrophages

Persistent activation of macrophages (MP)s into a proinflammatory M1 or anti-inflammatory M2 phenotype plays a role in several pathological conditions, including autoimmune diseases, fibrosis, infections, atherosclerosis and tumor development. The mannose receptor (MR, CD206), expressed at low levels on resting MPs and absent on M1 MPs, is highly expressed on M2 MPs, making it a potential target and drug delivery portal. Recently, we developed a novel, highly selective MR targeting ligand (MRTL), consisting of two mannose molecules separated by a monodisperse 12 unit poly(ethylene glycol) linker, to enhance the cellular uptake of polymeric nanocarriers. The feasibility of using the MRTL ligand for selectively targeting M2 MPs for intracellular delivery of nanoparticles (NPs) was investigated. Rat peritoneal MPs were differentiated into an M1 or M2 phenotype using IFN-γ and IL-4/IL-13, respectively. Expression of the M1 marker, inducible nitric oxide synthase (iNOS), and the M2 markers arginase (Arg)-1 and MR (at both the mRNA and protein levels) confirmed MP phenotypic activation. Resting, M1 and M2 MPs were treated with fluorescein isothiocyanate (FITC)-labeled MRTL or NPs displaying FITC-labeled MRTL at two surface densities (1 and 10%) and examined by confocal microscopy. Intracellular fluorescence was also quantified. Uptake of the MRTL was 2.4- and 11.8-fold higher in M2 MPs when compared to resting or M1 MPs, respectively, consistent with marker expression levels. Mannan, a competitive inhibitor of the MR, abrogated MRTL uptake. MRTL also co-localized with a fluid-phase endocytosis marker, further suggesting that uptake was mediated by MR-mediated endocytosis. Intracellular NP fluorescence was confirmed by flow cytometry and by confocal microscopy. MRTL-NPs accumulated intracellularly with no significant cell surface binding, suggesting efficient translocation. NPs displaying a low surface density (1%) of the MRTL exhibited significantly higher (2.3-fold) uptake into M2 MPs, relative to resting and M1 MPs. The 10% MRTL-NPs displayed greater uptake by M2 MPs when compared to resting and M1 MPs, but less uptake than 1% MRTL-NPs into M2 MPs. Control FITC-labeled plain NPs did not exhibit selective MP uptake. These studies demonstrate that M2 MPs are selectively targeted by NPs displaying a novel bivalent ligand that utilizes the MR as a target/portal for cell entry. This study also establishes the feasibility of the approach allowing for further investigation in vivo.

The Tumor Vessel Targeting Strategy: A Double-Edged Sword in Tumor Metastasis

Tumor vessels provide essential paths for tumor cells to escape from the primary tumor and form metastatic foci in distant organs. The vessel targeting strategy has been widely used as an important clinical cancer chemotherapeutic strategy for patients with metastatic tumors. Our review introduces the contribution of angiogenesis to tumor metastasis and summarizes the application of Food and Drug Administration (FDA)-approved vessel targeting drugs for metastatic tumors. We recommend the application and mechanisms of vascular targeting drugs for inhibiting tumor metastasis and discuss the risk and corresponding countermeasures after vessel targeting treatment.

Identification of prognostic genes in the acute myeloid leukemia microenvironment

The tumor microenvironment (TME) has a strong influence on the progression, therapeutic response, and clinical outcome of acute myeloid leukemia (AML), one of the most common hematopoietic malignancies in adults. In this study, we identified TME-related genes associated with AML prognosis. Gene expression profiles from AML patients were downloaded from TCGA database, and immune and stromal scores were calculated using the ESTIMATE algorithm. Immune scores were correlated with clinical features such as FAB subtypes and patient’s age. After categorizing AML cases into high and low score groups, an association between several differentially expressed genes (DEGs) and overall survival was identified. Functional enrichment analysis of the DEGs showed that they were primarily enriched in the immune response, inflammatory response, and cytokine activity, and were involved in signaling processes related to hematopoietic cell lineage, B cell receptor, and chemokine pathways. Two significant modules, dominated respectively by CCR5 and ITGAM nodes, were identified from the PPI network, and 20 hub genes were extracted. A total of 112 DEGs correlated with poor overall survival of AML patients, and 11 of those genes were validated in a separate TARGET-AML cohort. By identifying TME-associated genes, our findings may lead to improved prognoses and therapies for AML.

Antitumor activity of a novel dual functional podophyllotoxin derivative involved PI3K/AKT/mTOR pathway

The progression of cancer through local expansion and metastasis is well recognized, but preventing these characteristic cancer processes is challenging. To this end, a new strategy is required. In this study, we presented a novel dual functional podophyllotoxin derivative, 2-pyridinealdehyde hydrazone dithiocarbamate S-propionate podophyllotoxin ester (PtoxPdp), which inhibited both matrix metalloproteinases and Topoisomerase II. This new podophyllotoxin derivative exhibited significant anti-proliferative, anti-metastatic that correlated with the downregulation of matrix metalloproteinase. In a xenograft animal local expansion model, PtoxPdp was superior to etoposide in tumor repression. A preliminary mechanistic study revealed that PtoxPdp induced apoptosis and autophagy via the PI3K/AKT/mTOR pathway. Furthermore, PtoxPdp could also inhibit epithelial-mesenchymal transition, which was achieved by downregulating both PI3K/AKT/mTOR and NF-κB/Snail pathways. Taken together, our results reveal that PtoxPdp is a promising antitumor drug candidate.

High Tiam1 expression predicts positive lymphatic metastasis and worse survival in patients with malignant solid tumors: a systematic review and meta-analysis

Background

Many studies have explored the prognostic value of T-cell lymphoma invasion and metastasis inducing factor 1 (Tiam1) and its association with lymphatic metastasis in malignant solid tumors, but the conclusions remain controversial. Therefore, we performed a meta-analysis to systematically assess the prognostic value of Tiam1 expression and its association with lymphatic metastasis in malignant solid tumors.

Methods

We searched eligible studies in PubMed, Web of Science and EMBASE databases (from inception up to October 2018). The combined HR with 95% CI was used to estimate the prognostic value of Tiam1 expression. The correlation between Tiam1 expression and lymphatic metastasis was assessed using the combined odds ratio (OR) with 95% CI.

Results

A total of 17 studies with 2,228 patients with solid tumors were included in this meta-analysis. The overall estimated results showed that high Tiam1 expression was significantly associated with shorter overall survival (HR= 2.08, 95% CI: 1.62-2.68, P<0.01), and disease-free survival (HR = 1.86, 95% CI: 1.49-2.32, P<0.01). Besides, we also found that there was a close relationship between high Tiam1 expression and positive lymphatic metastasis (OR=2.63; 95% CI: 1.79-3.84, P<0.01).

Conclusion

High Tiam1 expression was significantly associated with shorter survival and positive lymphatic metastasis in patients with malignant solid tumors. Therefore, Tiam1 may be a promising prognostic biomarker and an effective therapeutic target for malignant solid tumors.

Phenotypic and transcriptomic characterization of canine myeloid-derived suppressor cells

Myeloid-derived suppressor cells (MDSCs) are key players in immune evasion, tumor progression and metastasis. MDSCs accumulate under various pathological states and fall into two functionally and phenotypically distinct subsets that have been identified in humans and mice: polymorphonuclear (PMN)-MDSCs and monocytic (M)-MDSCs. As dogs are an excellent model for human tumor development and progression, we set out to identify PMN-MDSCs and M-MDSCs in clinical canine oncology patients. Canine hypodense MHC class II^-CD5^-CD21^-CD11b⁺ cells can be subdivided into polymorphonuclear (CADO48A⁺CD14^-) and monocytic (CADO48A^-CD14⁺) MDSC subsets. The transcriptomic signatures of PMN-MDSCs and M-MDSCs are distinct, and moreover reveal a statistically significant similarity between canine and previously published human PMN-MDSC gene expression patterns. As in humans, peripheral blood frequencies of canine PMN-MDSCs and M-MDSCs are significantly higher in dogs with cancer compared to healthy control dogs (PMN-MDSCs: p < 0.001; M-MDSCs: p < 0.01). By leveraging the power of evolution, we also identified additional conserved genes in PMN-MDSCs of multiple species that may play a role in MDSC function. Our findings therefore validate the dog as a model for studying MDSCs in the context of cancer.

Low-Dose Total Body Irradiation Can Enhance Systemic Immune Related Response Induced by Hypo-Fractionated Radiation

A systemic immune related response (SIME) of radiotherapy has been occasionally observed on metastatic tumors, but the clinical outcomes remain poor. Novel treatment approaches are therefore needed to improve SIME ratio. We used a combination of hypo-fractionated radiation therapy (H-RT) with low-dose total body irradiation (L-TBI) in a syngeneic mouse model of breast and colon carcinoma. The combination therapy of H-RT and L-TBI potentially enhanced SIME by infiltration of CD8⁺ T cell and altering the immunosuppressive microenvironment in non-irradiated subcutaneous tumor lesions. The frequency of IFN-γ, as a tumor-specific CD8⁺ T cells producing, significantly inhibited the secondary tumor growth of breast and colon. Our findings suggest that L-TBI could serve as a potential therapeutic agent for metastatic breast and colon cancer and, together with H-RT, their therapeutic potential is enhanced significantly.

Delineating Pro-Angiogenic Myeloid Cells in Cancer Therapy

Recent evidence suggests that myeloid cells are critical in cancer development and therapy resistance processes. Pharmacological targeting of tumor-associated myeloid cells is an emerging approach among upcoming immune therapies. Surprisingly, myeloid cells are heterogeneous, including a subset of the myeloid cell displaying angiogenic properties in solid tumors. There is an urgent need to delineate angiogenic myeloid cell populations in order to facilitate specific targeting of protumor myeloid cells among heterogeneous pool. This review article is intended to compile all the relevant information in the literature for improved understanding of angiogenic myeloid cells and their role in tumor refractoriness to cancer therapy.

Potentiating cancer vaccine efficacy in liver cancer

Hepatocellular carcinoma (HCC) is the most common liver malignancy with a poor prognosis and an overall 5-year survival rate of approximately 5-6%. This is due because standard of care treatment options are limited and none of them shows a sufficient efficacy. HCC is an "inflammation-induced cancer" and preliminary preclinical and clinical data suggest that immunotherapeutic approaches may be a good alternative candidate for the treatment of HCC patients improving the dismal prognosis associated with this cancer. However, recent findings strongly suggest that an optimal immunotherapy in HCC requires the combination of an immune activator with immune modulators, aiming at compensating the strong liver immune suppressive microenvironment. One of the most promising strategy could be represented by the combination of a cancer vaccine with immunomodulatory drugs, such as chemotherapy and checkpoint inhibitors. Very limited examples of such combinatorial strategies have been evaluated in HCC to date, because HCC easily develops resistance to standard chemotherapy, which is also poorly tolerated by patients with liver cirrhosis. The present review describes the most update knowledge in this field.

Vaccine immunotherapy with ARNAX induces tumor-specific memory T cells and durable anti-tumor immunity in mouse models

Immunological checkpoint blockade therapies benefit a limited population of cancer patients. We have previously shown that vaccine immunotherapy with Toll‐like receptor (TLR)3‐adjuvant and tumor antigen overcomes anti‐programmed death ligand‐1 (PD‐L1) resistance in mouse tumor models. In the present study, 4 different ovalbumin (OVA)‐expressing tumor cell lines were implanted into syngeneic mice and subjected to anti‐tumor immunotherapy using ARNAX and whole OVA protein. ARNAX is a TLR3‐specific agonist that does not activate the mitochondrial antiviral‐signaling protein (MAVS) pathway, and thus does not induce systemic inflammation. Dendritic cell priming and proliferative CTL were induced by ARNAX + OVA, but complete remission was achieved only in a PD‐L1‐low cell line of EG7. Addition of anti‐PD‐L1 antibody to the ARNAX + OVA therapy brought complete remission to another PD‐L1‐high subline of EG7. Tumor shrinkage but not remission was observed in MO5 in that regimen. We analyzed tumor cells and tumor‐infiltrating immune cells to identify factors associated with successful ARNAX vaccine therapy. Tumors that responded to ARNAX therapy expressed high levels of MHC class I and low levels of PD‐L1. The tumor‐infiltrating immune cells in ARNAX‐susceptible tumors contained fewer immunosuppressive myeloid cells with low PD‐L1 expression. Combination with anti‐PD‐L1 antibody functioned not only within tumor sites but also within lymphoid tissues, augmenting the therapeutic efficacy of the ARNAX vaccine. Notably, ARNAX therapy induced memory CD8⁺ T cells and rejection of reimplanted tumors. Thus, ARNAX vaccine + anti‐PD‐L1 therapy enabled permanent remission against some tumors that stably present antigens.

Major Challenges and Potential Microenvironment-Targeted Therapies in Glioblastoma

Glioblastoma (GBM) is considered one of the most malignant, genetically heterogeneous, and therapy-resistant solid tumor. Therapeutic options are limited in GBM and involve surgical resection followed by chemotherapy and/or radiotherapy. Adjuvant therapies, including antiangiogenic treatments (AATs) targeting the VEGF–VEGFR pathway, have witnessed enhanced infiltration of bone marrow-derived myeloid cells, causing therapy resistance and tumor relapse in clinics and in preclinical models of GBM. This review article is focused on gathering previous clinical and preclinical reports featuring major challenges and lessons in GBM. Potential combination therapies targeting the tumor microenvironment (TME) to overcome the myeloid cell-mediated resistance problem in GBM are discussed. Future directions are focused on the use of TME-directed therapies in combination with standard therapy in clinical trials, and the exploration of novel therapies and GBM models for preclinical studies. We believe this review will guide the future of GBM research and therapy.

Arachidonic Acid Metabolite as a Novel Therapeutic Target in Breast Cancer Metastasis

Metastatic breast cancer (BC) (also referred to as stage IV) spreads beyond the breast to the bones, lungs, liver, or brain and is a major contributor to the deaths of cancer patients. Interestingly, metastasis is a result of stroma-coordinated hallmarks such as invasion and migration of the tumor cells from the primary niche, regrowth of the invading tumor cells in the distant organs, proliferation, vascularization, and immune suppression. Targeted therapies, when used as monotherapies or combination therapies, have shown limited success in decreasing the established metastatic growth and improving survival. Thus, novel therapeutic targets are warranted to improve the metastasis outcomes. We have been actively investigating the cytochrome P450 4 (CYP4) family of enzymes that can biosynthesize 20-hydroxyeicosatetraenoic acid (20-HETE), an important signaling eicosanoid involved in the regulation of vascular tone and angiogenesis. We have shown that 20-HETE can activate several intracellular protein kinases, pro-inflammatory mediators, and chemokines in cancer. This review article is focused on understanding the role of the arachidonic acid metabolic pathway in BC metastasis with an emphasis on 20-HETE as a novel therapeutic target to decrease BC metastasis. We have discussed all the significant investigational mechanisms and put forward studies showing how 20-HETE can promote angiogenesis and metastasis, and how its inhibition could affect the metastatic niches. Potential adjuvant therapies targeting the tumor microenvironment showing anti-tumor properties against BC and its lung metastasis are discussed at the end. This review will highlight the importance of exploring tumor-inherent and stromal-inherent metabolic pathways in the development of novel therapeutics for treating BC metastasis.

Cancer immunotherapy: how low-level ionizing radiation can play a key role

The cancer immunoediting hypothesis assumes that the immune system guards the host against the incipient cancer, but also "edits" the immunogenicity of surviving neoplastic cells and supports remodeling of tumor microenvironment towards an immunosuppressive and pro-neoplastic state. Local irradiation of tumors during standard radiotherapy, by killing neoplastic cells and generating inflammation, stimulates anti-cancer immunity and/or partially reverses cancer-promoting immunosuppression. These effects are induced by moderate (0.1-2.0 Gy) or high (>2 Gy) doses of ionizing radiation which can also harm normal tissues, impede immune functions, and increase the risk of secondary neoplasms. In contrast, such complications do not occur with exposures to low doses (≤0.1 Gy for acute irradiation or ≤0.1 mGy/min dose rate for chronic exposures) of low-LET ionizing radiation. Furthermore, considerable evidence indicates that such low-level radiation (LLR) exposures retard the development of neoplasms in humans and experimental animals. Here, we review immunosuppressive mechanisms induced by growing tumors as well as immunomodulatory effects of LLR evidently or likely associated with cancer-inhibiting outcomes of such exposures. We also offer suggestions how LLR may restore and/or stimulate effective anti-tumor immunity during the more advanced stages of carcinogenesis. We postulate that, based on epidemiological and experimental data amassed over the last few decades, whole- or half-body irradiations with LLR should be systematically examined for its potential to be a viable immunotherapeutic treatment option for patients with systemic cancer.

Gene Electrotransfer of Plasmid-Encoding IL-12 Recruits the M1 Macrophages and Antigen-Presenting Cells Inducing the Eradication of Aggressive B16F10 Murine Melanoma

Cancer immunotherapy is currently one of the leading approaches in cancer treatment. Gene electrotransfer of plasmids encoding interleukin 12 (IL-12) into the cells leads to the production of IL-12, which drives immune cell polarization to an antitumoral response. One of the cell types that shows great promise in targeting tumor cells under the influence of IL-12 cytokine milieu is that of macrophages. Therefore, the aim of this study was to evaluate gene electrotransfer of antibiotic resistance-free plasmid DNA-encoding murine IL-12 (mIL-12) in mice bearing aggressive B16F10 murine melanoma. IL-12 electrotransfer resulted in the complete long-term eradication of the tumors. Serum mIL-12 and murine interferon γ (mIFNγ) were increased after IL-12 gene electrotransfer. Further on, hematoxylin and eosin (HE) staining showed increased infiltration of immune cells that lasted from day 4 until day 14. Immunohistochemistry (IHC) staining of F4/80, MHCII, and CD11c showed higher positive staining in the IL-12 gene electrotransfer group than in the control groups. Immune cell infiltration into the tumors and the high density of MHCII- and CD11c-positive cells suggest an antitumor polarization of macrophages and the presence of antigen-presenting cells that contributes to the important antitumor effectiveness of IL-12.

Vascular mimicry in glioblastoma following anti-angiogenic and anti-20-HETE therapies

Glioblastoma (GBM) is one hypervascular and hypoxic tumor known among solid tumors. Antiangiogenic therapeutics (AATs) have been tested as an adjuvant to normalize blood vessels and control abnormal vasculature. Evidence of relapse exemplified in the progressive tumor growth following AAT reflects development of resistance to AATs. Here, we identified that GBM following AAT (Vatalanib) acquired an alternate mechanism to support tumor growth, called vascular mimicry (VM). We observed that Vatalanib induced VM vessels are positive for periodic acid-Schiff (PAS) matrix but devoid of any endothelium on the inner side and lined by tumor cells on the outer-side. The PAS+ matrix is positive for basal laminae (laminin) indicating vascular structures. Vatalanib treated GBM displayed various stages of VM such as initiation (mosaic), sustenance, and full-blown VM. Mature VM structures contain red blood cells (RBC) and bear semblance to the functional blood vessel-like structures, which provide all growth factors to favor tumor growth. Vatalanib treatment significantly increased VM especially in the core of the tumor, where HIF-1α was highly expressed in tumor cells. VM vessels correlate with hypoxia and are characterized by co-localized MHC-1+ tumor and HIF-1α expression. Interestingly, 20-HETE synthesis inhibitor HET0016 significantly decreased GBM tumors through decreasing VM structures both at the core and at periphery of the tumors. In summary, AAT induced resistance characterized by VM is an alternative mechanism adopted by tumors to make functional vessels by transdifferentiation of tumor cells into endothelial-like cells to supply nutrients in the event of hypoxia. AAT induced VM is a potential therapeutic target of the novel formulation of HET0016. Our present study suggests that HET0016 has a potential to target therapeutic resistance and can be combined with other antitumor agents in preclinical and clinical trials.

Cancer Therapeutics Following Newton's Third Law

Cancer is a wound that never heals. This is suggested by the data produced after several years of cancer research and therapeutic interventions done worldwide. There is a strong similarity between Newton's third law and therapeutic behavior of tumor. According to Newton's third law "for every action, there is an equal and opposite reaction". In cancer therapeutics, tumor exerts strong pro-tumor response against applied treatment and imposes therapeutic resistance, one of the major problems seen in preclinical and clinical studies. There is an urgent need to understand the tumor biology of therapy resistant tumors following the therapy. Here, we have discussed the problem and provided possible path for future studies to treat cancer.