MMP-9 from sublethally irradiated tumor promotes Lewis lung carcinoma cell invasiveness and pulmonary metastasis

The mechanism of action of myricetin against lung adenocarcinoma based on bioinformatics, in silico and in vitro experiments

Myricetin is a natural flavonoid with anti-cancer and anti-inflammatory effects, but its mechanism for treating lung adenocarcinoma (LUAD) remains unclearly. Therefore, bioinformatics, in silico and in vitro experiments were employed to elucidate this issue in this study. The core targets of myricetin against LUAD were screened by PharmaMapper (v2017), Assistant for Clinical Bioinformatics, STRING (v11.5) and Cytoscape (v3.8.1). Using Kaplan-Meier Plotter (v2022.04.20), UALCAN (v2021.12.13) and GEPIA (v2.0) databases, the correlation between core genes and the prognosis of LUAD patients were analyzed, and the expression levels of core genes were verified. In silico studies were used to analyze the binding energies and sites of myricetin with core genes. The effects of myricetin on H1975 cells were explored through thiazolyl blue (MTT), cell migration, colony formation and western blot assays. A total of 72 potential targets of myricetin against LUAD were identified through bioinformatics. Among the four core targets obtained by multiple networks and in silico assays, the up-regulated MMP9 (HR = 1.14 (1-1.29), logrank P = 0.046) and down-regulated PIK3R1 (HR = 0.58 (0.51-0.66), logrank P < 1E-16) were positively correlated with poor survival outcomes in LUAD patients. In vitro experiments demonstrated that myricetin inhibited the proliferation and migration of H1975 cells, promoting their apoptosis. Myricetin inhibits the proliferation of H1975 cells and induces cell apoptosis through its influence on the expression levels of MMP1, MMP3, MMP9, and PIK3R1 and regulating the multiple pathways these genes participate in. Both MMP9 and PIK3R1 are potential biomarkers for LUAD.

ILT4 facilitates angiogenesis in non-small cell lung cancer

Antiangiogenic therapy targeting VEGF-A has become the standard of first-line therapy for non-small cell lung cancer (NSCLC). However, its clinical response rate is still less than 50%, and most patients eventually develop resistance, even when using combination therapy with chemotherapy. The major cause of resistance is the activation of complex bypass signals that induce angiogenesis and tumor progression. Therefore, exploring novel proangiogenic mechanisms and developing promising targets for combination therapy are crucial for improving the efficacy of antiangiogenic therapy. Immunoglobulin-like transcript (ILT) 4 is a classic immunosuppressive molecule that inhibits myeloid cell activation. Recent studies have shown that tumor cell-derived ILT4 drives tumor progression via the induction of malignant biologies and creation of an immunosuppressive microenvironment. However, whether and how ILT4 participates in NSCLC angiogenesis remain elusive. Herein, we found that enriched ILT4 in NSCLC is positively correlated with high microvessel density, advanced disease, and poor overall survival. Tumor cell-derived ILT4 induced angiogenesis both in vitro and in vivo and tumor progression and metastasis in vivo. Mechanistically, ILT4 was upregulated by its ligand angiopoietin-like protein 2 (ANGPTL2). Their interaction subsequently activated the ERK1/2 signaling pathway to increase the secretion of the proangiogenic factors VEGF-A and MMP-9, which are responsible for NSCLC angiogenesis. Our study explored a novel mechanism for ILT4-induced tumor progression and provided a potential target for antiangiogenic therapy in NSCLC.

MMP-9 reinforces radiation-induced delayed invasion and metastasis of neuroblastoma cells through second-signaling positive feedback with NFκB via both ERK and IKK activation

Neuroblastoma (NB) progression is branded with hematogenous metastasis and frequent relapses. Despite intensive multimodal clinical therapy, outcomes for patients with progressive disease remain poor, with negligible long-term survival. Therefore, understanding the acquired molecular rearrangements in NB cells with therapy pressure and developing improved therapeutic strategies is a critical need to improve the outcomes for high-risk NB patients. We investigated the rearrangement of MMP9 in NB with therapy pressure, and unveiled the signaling that facilitates NB evolution. Radiation-treatment (RT) significantly increased MMP9 expression/activity, and the induced enzyme activity was persistently maintained across NB cell lines. Furthermore, RT-triggered NFκB transcriptional activity and this RT-induced NFκB were required/adequate for MMP9 maintenance. RT-triggered NFκB-dependent MMP9 actuated a second-signaling feedback to NFκB, facilitating a NFκB-MMP9-NFκB positive feedback cycle (PFC). Critically, MMP9-NFκB feedback is mediated by MMP9-dependent activation of IKKβ and ERK phosphotransferase activity. Beyond its tumor invasion/metastasis function, PFC-dependent MMP9 lessens RT-induced apoptosis and favors survival pathway through the activation of NFκB signaling. In addition, PFC-dependent MMP9 regulates 19 critical molecular determinants that play a pivotal role in tumor evolution. Interestingly, seven of 19 genes possess NFκB-binding sites, demonstrating that MMP9 regulates these molecules by activating NFκB. Collectively, these data suggest that RT-triggered NFκB-dependent MMP9 actuates feedback to NFκB though IKKβ- and ERK1/2-dependent IκBα phosphorylation. This RT-triggered PFC prompts MMP9-dependent survival advantage, tumor growth, and dissemination. Targeting therapy-pressure-driven PFC and/or selective inhibition of MMP9 maintenance could serve as promising therapeutic strategies for treatment of progressive NB.

Telomerase deficiency and dysfunctional telomeres in the lung tumor microenvironment impair tumor progression in NSCLC mouse models and patient-derived xenografts

Non-small cell lung cancer (NSCLC) is a leading cause of cancer death. Tumor progression depends on interactions of cancer cells with the tumor microenvironment. Here, we find increased copy number and mRNA expression of the catalytic subunit of telomerase, TERT, in tumors from NSCLC patients, contributing to a lower survival. Moreover, TERT expression in NSCLC patients from the TCGA cohort is mainly associated to the reduced infiltration of CD8⁺ T lymphocytes, as well as to increased infiltration of myeloid-derived suppressor cells (MDSCs). We also show that TERT deficiency and dysfunctional telomeres induced by 6-thio-dG treatment in mice reduced lung tumor implantation and vascularization, increased DNA damage response, cell cycle arrest and apoptosis, as well as reduced proliferation, inflammation, lung tumor immunosupression and invasion upon induction of a Lewis lung carcinoma (LLC). Furthermore, 6-thio-dG-treated human NSCLC xenografts exhibited increased telomere damage, cell cycle arrest and apoptosis, as well as reduced proliferation, resulting in a reduced tumor growth. Our results show that targeting telomeres might be an effective therapeutic strategy in NSCLC.

Selective inhibition of HDAC6 promotes bladder cancer radiosensitization and mitigates the radiation-induced CXCL1 signalling

BACKGROUND

Although trimodality therapy resecting tumours followed by chemoradiotherapy is emerged for muscle-invasive bladder cancer (MIBC), chemotherapy produces toxicities. Histone deacetylase inhibitors have been identified as an effective strategy to enhance cancer radiotherapy (RT).

METHODS

We examined the role of HDAC6 and specific inhibition of HDAC6 on BC radiosensitivity by performing transcriptomic analysis and mechanism study.

RESULTS

HDAC6 knockdown or HDAC6 inhibitor (HDAC6i) tubacin exerted a radiosensitizing effect, including decreased clonogenic survival, increased H3K9ac and α-tubulin acetylation, and accumulated γH2AX, which are similar to the effect of panobinostat, a pan-HDACi, on irradiated BC cells. Transcriptomics of shHDAC6-transduced T24 under irradiation showed that shHDAC6 counteracted RT-induced mRNA expression of CXCL1, SERPINE1, SDC1 and SDC2, which are linked to cell migration, angiogenesis and metastasis. Moreover, tubacin significantly suppressed RT-induced CXCL1 and radiation-enhanced invasion/migration, whereas panobinostat elevated RT-induced CXCL1 expression and invasion/migration abilities. This phenotype was significantly abrogated by anti-CXCL1 antibody, indicating the key regulator of CXCL1 contributing to BC malignancy. Immunohistochemical evaluation of tumours from urothelial carcinoma patients supported the correlation between high CXCL1 expression and reduced survival.

CONCLUSION

Unlike pan-HDACi, the selective HDAC6i can enhance BC radiosensitization and effectively inhibit RT-induced oncogenic CXCL1-Snail-signalling, thus further advancing its therapeutic potential with RT.

How does plasticity of migration help tumor cells to avoid treatment: Cytoskeletal regulators and potential markers

Tumor shrinkage as a result of antitumor therapy is not the only and sufficient indicator of treatment success. Cancer progression leads to dissemination of tumor cells and formation of metastases - secondary tumor lesions in distant organs. Metastasis is associated with acquisition of mobile phenotype by tumor cells as a result of epithelial-to-mesenchymal transition and further cell migration based on cytoskeleton reorganization. The main mechanisms of individual cell migration are either mesenchymal, which depends on the activity of small GTPase Rac, actin polymerization, formation of adhesions with extracellular matrix and activity of proteolytic enzymes or amoeboid, which is based on the increase in intracellular pressure caused by the enhancement of actin cortex contractility regulated by Rho-ROCK-MLCKII pathway, and does not depend on the formation of adhesive structures with the matrix, nor on the activity of proteases. The ability of tumor cells to switch from one motility mode to another depending on cell context and environmental conditions, termed migratory plasticity, contributes to the efficiency of dissemination and often allows the cells to avoid the applied treatment. The search for new therapeutic targets among cytoskeletal proteins offers an opportunity to directly influence cell migration. For successful treatment it is important to assess the likelihood of migratory plasticity in a particular tumor. Therefore, the search for specific markers that can indicate a high probability of migratory plasticity is very important.

Lung transcriptome of nonhuman primates exposed to total- and partial-body irradiation

The focus of radiation biodosimetry has changed recently, and a paradigm shift for using molecular technologies of omic platforms in addition to cytogenetic techniques has been observed. In our study, we have used a nonhuman primate model to investigate the impact of a supralethal dose of 12 Gy radiation on alterations in the lung transcriptome. We used 6 healthy and 32 irradiated animal samples to delineate radiation-induced changes. We also used a medical countermeasure, γ-tocotrienol (GT3), to observe any changes. We demonstrate significant radiation-induced changes in the lung transcriptome for total-body irradiation (TBI) and partial-body irradiation (PBI). However, no major influence of GT3 on radiation was noted in either comparison. Several common signaling pathways, including PI3K/AKT, GADD45, and p53, were upregulated in both exposures. TBI activated DNA-damage-related pathways in the lungs, whereas PTEN signaling was activated after PBI. Our study highlights the various transcriptional profiles associated with γ- and X-ray exposures, and the associated pathways include LXR/RXR activation in TBI, whereas pulmonary wound-healing and pulmonary fibrosis signaling was repressed in PBI. Our study provides important insights into the molecular pathways associated with irradiation that can be further investigated for biomarker discovery.

IGF1R acts as a cancer-promoting factor in the tumor microenvironment facilitating lung metastasis implantation and progression

Given the long-term ineffectiveness of current therapies and late-stage diagnoses, lung cancer is a leading cause of malignant diseases. Tumor progression is influenced by cancer cell interactions with the tumor microenvironment (TME). Insulin-like growth factor 1 receptor (IGF1R) was reported to affect the TME; however, the role of IGF1R in lung TME has not been investigated. First, we assessed IGF1R genomic alterations and expression in NSCLC patient tissue samples, as well as IGF1R serum levels. Next, we performed tumor heterotopic transplantation and pulmonary metastases in IGF1R-deficient mice using melanoma and Lewis lung carcinoma (LLC) cells. Herein we report increased amplification and mRNA expression, as well as increased protein expression (IGF1R/p-IGF1R) and IGF1R levels in tumor samples and serum from NSCLC patients, respectively. Moreover, IGF1R deficiency in mice reduced tumor growth, proliferation, inflammation and vascularization, and increased apoptosis after tumor heterotopic transplantation. Following induction of lung metastasis, IGF1R-deficient lungs also demonstrated a reduced tumor burden, and decreased expression of tumor progression markers, p-IGF1R and p-ERK1/2. Additionally, IGF1R-deficient lungs showed increased apoptosis and diminished proliferation, vascularization, EMT and fibrosis, along with attenuated inflammation and immunosuppression. Accordingly, IGF1R deficiency decreased expression of p-IGF1R in blood vessels, fibroblasts, tumor-associated macrophages and FOXP3⁺ tumor-infiltrating lymphocytes. Our results demonstrate that IGF1R promotes metastatic tumor initiation and progression in lung TME. Furthermore, our research indicates that IGF1R could be a potential biomarker for early prediction of drug response and clinical evolution in NSCLC patients.

Inhibition of c-MET reverses radiation-induced malignant potential in pancreatic cancer

As a treatment option for PDAC, radiation therapy induces good local control. However, radiation also reportedly enhances the malignant potential (e.g., invasion and migration ability) in various cancers, thus increasing the risk of distant metastasis. It remains unclear how radiation induces malignant potential, and how such enhanced malignant potential can be suppressed. In the current study, we evaluated the sequential change of c-Met expression in pancreatic cancer cells following irradiation. We found that irradiation transiently induced c-Met expression in vitro. In an in vivo subcutaneous tumor mouse model, irradiation also enhanced downstream phosphorylated Met (p-Met). Furthermore, this enhancement of p-Met protein expression was suppressed by oral administration of the c-Met inhibitor INC280. Irradiated pancreatic cancer cells with enhanced c-Met expression exhibited higher malignant potential, including invasion and migration ability, compared with cells showing low c-Met expression. Pancreatic cancer cells that overexpressed c-met also showed enhanced malignant potential, which was reversed by c-Met inhibition. Additionally, c-Met inhibitor suppressed the metastatic potential in a liver metastasis mouse model using c-met-overexpressing cells. Overall, our present results revealed that irradiation could induce c-met expression in pancreatic cancer cells, leading to enhanced malignant potential (e.g., invasion and migration ability) and thus promoting distant metastasis. Moreover, a c-Met inhibitor could reverse this enhanced malignant potential.

The genomic architecture of metastasis in breast cancer: focus on mechanistic aspects, signalling pathways and therapeutic strategies

Breast cancer is a multifactorial, heterogeneous disease and the second most frequent cancer amongst women worldwide. Metastasis is one of the most leading causes of death in these patients. Early-stage or locally advanced breast cancer is limited to the breast or nearby lymph nodes. When breast cancer spreads to farther tissues/organs from its original site, it is referred to as metastatic or stage IV breast cancer. Normal breast development is regulated by specific genes and signalling pathways controlling cell proliferation, cell death, cell differentiation and cell motility. Dysregulation of genes involved in various signalling pathways not only leads to the formation of primary tumour but also to the metastasis as well. The metastatic cascade is represented by a multi-step process including invasion of the local tumour cell followed by its entry into the vasculature, exit of malignant cells from the circulation and ultimately their colonization at the distant sites. These stages are referred to as formation of primary tumour, angiogenesis, invasion, intravasation and extravasation, respectively. The major sites of metastasis of breast cancer are the lymph nodes, bone, brain and lung. Only about 28% five-year survival rate has been reported for stage IV breast cancer. Metastasis is a serious concern for breast cancer and therefore, various therapeutic strategies such as tyrosine kinase inhibitors have been developed to target specific dysregulated genes and various signalling pathways involved in different steps of metastasis. In addition, other therapies like hyperbaric oxygen therapy, RNA interference and CRISPR/Cas9 are also being explored as novel strategies to cure the stage IV/metastatic breast cancer. Therefore, the current review has been compiled with an aim to evaluate the genetic basis of stage IV breast cancer with a focus on the molecular mechanisms. In addition, the therapeutic strategies targeting these dysregulated genes involved in various signalling pathways have also been discussed. Genome editing technologies that can target specific genes in the affected areas by making knock-in and knock-out alternations and thereby bring significant treatment outcomes in breast cancer have also been summarized.

Combined Radiochemotherapy: Metalloproteinases Revisited

Besides cytotoxic DNA damage irradiation of tumor cells triggers multiple intra- and intercellular signaling processes, that are part of a multilayered, treatment-induced stress response at the unicellular and tumor pathophysiological level. These processes are intertwined with intrinsic and acquired resistance mechanisms to the toxic effects of ionizing radiation and thereby co-determine the tumor response to radiotherapy. Proteolysis of structural elements and bioactive signaling moieties represents a major class of posttranslational modifications regulating intra- and intercellular communication. Plasma membrane-located and secreted metalloproteinases comprise a family of metal-, usually zinc-, dependent endopeptidases and sheddases with a broad variety of substrates including components of the extracellular matrix, cyto- and chemokines, growth and pro-angiogenic factors. Thereby, metalloproteinases play an important role in matrix remodeling and auto- and paracrine intercellular communication regulating tumor growth, angiogenesis, immune cell infiltration, tumor cell dissemination, and subsequently the response to cancer treatment. While metalloproteinases have long been identified as promising target structures for anti-cancer agents, previous pharmaceutical approaches mostly failed due to unwanted side effects related to the structural similarities among the multiple family members. Nevertheless, targeting of metalloproteinases still represents an interesting rationale alone and in combination with other treatment modalities. Here, we will give an overview on the role of metalloproteinases in the irradiated tumor microenvironment and discuss the therapeutic potential of using more specific metalloproteinase inhibitors in combination with radiotherapy.

Myeloid cell-derived PROS1 inhibits tumor metastasis by regulating inflammatory and immune responses via IL-10

Stimulation of TAM (TYRO3, AXL, and MERTK) receptor tyrosine kinases promotes tumor progression through numerous cellular mechanisms. TAM cognate ligands GAS6 and PROS1 (for TYRO3 and MERTK) are secreted by host immune cells, an interaction which may support tumor progression. Here, we revealed an unexpected antimetastatic role for myeloid-derived PROS1: suppressing metastatic potential in lung and breast tumor models. Pros1 deletion in myeloid cells led to increased lung metastasis, independent of primary tumor infiltration. PROS1-cKO bone marrow-derived macrophages (BMDMs) led to elevated TNF-α, IL-6, Nos2, and IL-10 via modulation of the Socs3/NF-κB pathway. Conditioned medium from cKO BMDMs enhanced EMT, ERK, AKT, and STAT3 activation within tumor cells and promoted IL-10-dependent invasion and survival. Macrophages isolated from metastatic lungs modulated T cell proliferation and function, as well as expression of costimulatory molecules on DCs in a PROS1-dependent manner. Inhibition of MERTK kinase activity blocked PROS1-mediated suppression of TNF-α and IL-6 but not IL-10. Overall, using lung and breast cancer models, we identified the PROS1/MERTK axis within BMDMs as a potent regulator of adaptive immune responses with a potential to suppress metastatic seeding and revealed IL-10 regulation by PROS1 to deviate from that of TNF-α and IL-6.

Advancement and properties of circular RNAs in prostate cancer: An emerging and compelling frontier for discovering

Prostate cancer (PC) is the most common carcinoma among men worldwide which results in 26% of leading causes of cancer-related death. However, the ideal and effective molecular marker remains elusive. CircRNA, initially observed in plant-infected viruses and Sendai virus in 1979, is generated from pre-mRNA back-splicing and comes in to play by adequate expression. The differential expression in prostate tissues compared with the control reveals the promising capacity in modulating processes including carcinogenesis and metastasis. However, the biological mechanisms of regulatory network in PC needs to systemically concluded. In this review, we enlightened the comprehensive studies on the definite mechanisms of circRNAs affecting tumor progression and metastasis. What's more, we validated the potential clinical application of circRNAs serving as diagnostic and prognostic biomarker. The discussion and analysis in circRNAs will broaden our knowledge of the pathogenesis of PC and further optimize the current therapies against different condition.

Heterogeneity of circulating tumor cell dissemination and lung metastases in a subcutaneous Lewis lung carcinoma model

Subcutaneous (s.c.) tumor models are widely used in pre-clinical cancer metastasis research. Despite this, the dynamics and natural progression of circulating tumor cells (CTCs) and CTC clusters (CTCCs) in peripheral blood are poorly understood in these models. In this work, we used a new technique called 'diffuse in vivo flow cytometry' (DiFC) to study CTC and CTCC dissemination in an s.c. Lewis lung carcinoma (LLC) model in mice. Tumors were grown in the rear flank and we performed DiFC up to 31 days after inoculation. At the study endpoint, lungs were excised and bioluminescence imaging (BLI) was performed to determine the extent of lung metastases. We also used fluorescence macro-cryotome imaging to visualize infiltration and growth of the primary tumor. DiFC revealed significant heterogeneity in CTC and CTCC numbers amongst all mice studied, despite using clonally identical LLC cells and tumor placement. Maximum DiFC count rates corresponded to 0.1 to 14 CTCs per mL of peripheral blood. In general, CTC numbers did not necessarily increase monotonically over time and were poorly correlated with tumor volume. However, there was a good correlation between CTC and CTCC numbers in peripheral blood and lung metastases. We attribute the differences in CTC numbers primarily due to growth patterns of the primary tumor. This study is one of the few reports of CTC shedding dynamics in sub-cutaneous metastasis models and underscores the value of in vivo methods for continuous, non-invasive CTC monitoring.

Irradiation induces cancer lung metastasis through activation of the cGAS-STING-CCL5 pathway in mesenchymal stromal cells

Emerging evidence indicates that mesenchymal stromal cells (MSCs) have an important role in cancer metastasis. Although tumor microenvironment, which includes MSCs and immune cells, can be altered by ionizing radiation (IR), whether irradiation can promote metastasis through MSCs remains unclear. Using the lung colonization model of transplanted 4T1 breast cancer cells, we found an increased lung metastasis in mice exposed to ionizing radiation, even when the thorax was shielded during whole-body irradiation. This radiation-induced lung metastasis can be replicated using irradiated MSCs. cGAS-STING signaling pathway was found to be activated in MSCs, accompanied by upregulation of type I interferon-related genes, including chemokine CCL5. Disruption of cGAS-STING signaling in MSCs abolished their pro-metastatic effect. Deletion of CCL5 in MSCs also abrogated the pro-metastatic effect endowed by IR. Furthermore, we showed that the lung pro-metastatic effect of irradiated MSCs required the presence of macrophages. Our results indicate that radiation-induced alterations in distant mesenchymal stromal cells facilitate cancer metastasis.

Redirecting extracellular proteases to molecularly guide radiosensitizing drugs to tumors

Patients with advanced cancers are treated with combined radiotherapy and chemotherapy, however curability is poor and treatment side effects severe. Drugs sensitizing tumors to radiotherapy have been developed to improve cell kill, but tumor specificity remains challenging. To achieve tumor selectivity of small molecule radiosensitizers, we tested as a strategy active tumor targeting using peptide-based drug conjugates. We attached an inhibitor of the DNA damage response to antibody or cell penetrating peptides. Antibody drug conjugates honed in on tumor overexpressed cell surface receptors with high specificity but lacked efficacy when conjugated to the DNA damage checkpoint kinase inhibitor AZD7762. As an alternative approach, we synthesized activatable cell penetrating peptide scaffolds that accumulated within tumors based on matrix metalloproteinase cleavage. While matrix metalloproteinases are integral to tumor progression, they have proven therapeutically elusive. We harnessed these pro-tumorigenic extracellular proteases to spatially guide radiosensitizer drug delivery using cleavable activatable cell penetrating peptides. Here, we tested the potential of these two drug delivery platforms targeting distinct tumor compartments in combination with radiotherapy and demonstrate the advantages of protease triggered cell penetrating peptide scaffolds over antibody drug conjugates to deliver small molecule amine radiosensitizers.

Targeting human epidermal growth factor receptor 2 enhances radiosensitivity and reduces the metastatic potential of Lewis lung carcinoma cells

BACKGROUND

Sublethal radiation induces matrix metalloproteinase 9 (MMP-9)-mediated radioresistance in Lewis lung carcinoma (LLC) cells and their metastatic dissemination. We aim to determine if EGFR/HER2 activation associates with MMP-9-mediated radioresistance and invasiveness in irradiated LLC cells.

METHODS

LLC cells were treated with erlotinib or afatinib followed by sublethal radiation. After irradiation, we examined the phosphorylation of EGFR/HER2 and MMP-9 expression. Colony formation assay determined if the kinase inhibitors sensitize LLC cells to radiation. Matrigel-coated Boyden chamber assay assessed cellular invasiveness. Resulting tumors of wild-type LLC cells or HER2 knock-down mutant cells were irradiated to induce pulmonary metastases.

RESULTS

Afatinib more effectively sensitized LLC cells to radiation and decreased invasiveness by inhibiting phosphorylation of EGFR, HER2, Akt, ERK, and p38, and down-regulating MMP-9 when compared to erlotinib. Afatinib abolished radiation-induced lung metastases in vivo. Furthermore, LLC HER2 knock-down cells treated with radiation had growth inhibition.

CONCLUSION

Dual inhibition of radiation-activated EGFR and HER2 signaling by afatinib suppressed the proliferation and invasion of irradiated LLC cells. Increased radiosensitivity and decreased metastatic dissemination were observed by pharmacological or genetic HER2 inhibition in vivo. These findings indicate that HER2 plays a pivotal role in enhancing radioresistance and reducing metastatic potential of LLC cells.

Surface-Mediated Stimuli-Responsive Gene Delivery Based on Breath Figure Film Combined with Matrix Metalloproteinase-Sensitive Hydrogel

Surface-mediated gene delivery appears to be potential gene delivery modes for various applications. Still, controlled and smart delivery manners are required especially considering the need for gene therapy to deliver gene with selectivity. A surface that can effectively payload DNA, promote cell adhesion, and stimuli response is an important prerequisite. Here, we report a matrix metalloproteinase (MMP)-responsive surface-mediated gene delivery system by combining MMP-degradable hydrogel with a breath figure (BF) porous film. The MMP-degradable hydrogel containing plasmid DNA was loaded into the surface pores of the BF film as DNA reservoirs. The upper surface without hydrogel on the BF film served as footholds of integrin adhesions. MMP is one of the important endogenous signals in tumor-related pathologic changes, and MMP expressions in cancer cells are significantly higher than those in normal cells. Consequently, our surface-mediated gene delivery locally and rapidly released the payload DNA in response to cancer cells and transfected them. This work highlights the importance of the combination of stimuli-response and surface-mediated gene delivery to functional materials, showing good potential applications in the field of gene therapy.

Increased expression of MMP-2 and MMP-9 indicates poor prognosis in glioma recurrence

The main characteristic of glioma is recurrence, even after intensive multidisciplinary treatment. Studies show that enhanced invasive ability will increase the ability of tumor cells to escape from the primary tumor mass, which is a key factor contributing to tumor relapse and recurrence. In this study, we assessed the expression of MMP-2, MMP-9, two important matrix metallopeptidases that increase the invasive ability of glioma, and their suppressors, TIMP-1, TIMP-2 in glioma tissues from primary and recurrent glioma patients by immunohistochemistry. Glioma cells and nude mice were used for in vitro and in vivo studies. Results showed that the expression of MMP-2 and MMP-9 in recurrent gliomas were significantly higher than those in primary gliomas (P = 3.075 × 10^{-11, P = 1.510 × 10-5}, respectively). We also found that radiotherapy increased the expression of MMP-9, but had no effect on MMP-2 and TIMP-1/2. With glioma cell line U251, we found that irradiation increased the expression of MMP-9 in vitro. Tumor tissues from an orthotopic xenograft model showed that after irradiation treatment, the expression of MMP-9 increased significantly in vivo. We also found that knocking down MMP-9 decreased irradiation-induced invasion obviously. Above all, we concluded that higher expressions of MMP-2/-9 indicate poor prognosis in glioma recurrence. The increased expression of MMP-9 after radiotherapy suggests that MMP-9 might be an important target in the radiosensitization of glioma.

Gelatinase B/matrix metalloproteinase-9 and other neutrophil proteases switch off interleukin-2 activity

Interleukin 2 (IL-2) is critical for T cell development and homeostasis, being a key regulator of adaptive immune responses in autoimmunity, hypersensitivity reactions and cancer. Therefore, its abundance in serum and peripheral tissues needs tight control. Here, we described a new mechanism contributing to the immunobiology of IL-2. We demonstrated, both in biochemical and cell-based assays, that IL-2 is subject to proteolytic processing by neutrophil matrix metalloproteinase-9 (MMP-9). IL-2 fragments produced after cleavage by MMP-9 remained linked by a disulfide bond and displayed a reduced affinity for all IL-2 receptor subunits and a distinct pattern and timing of signal transduction. Stimulation of IL-2-dependent cells, including murine CTLL-2 and primary human regulatory T cells, with cleaved IL-2 resulted in significantly decreased proliferation. The concerted action of neutrophil proteases destroyed IL-2. Our data suggest that in neutrophil-rich inflammatory conditions in vivo, neutrophil MMP-9 may reduce the abundance of signaling-competent IL-2 and generate a fragment that competes with IL-2 for receptor binding, whereas the combined activity of granulocyte proteases has the potential to degrade and thus eliminate bioavailable IL-2.

Matrix metalloproteinases participation in the metastatic process and their diagnostic and therapeutic applications in cancer

Matrix metalloproteinases (MMPs) participate from the initial phases of cancer onset to the settlement of a metastatic niche in a second organ. Their role in cancer progression is related to their involvement in the extracellular matrix (ECM) degradation and in the regulation and processing of adhesion and cytoskeletal proteins, growth factors, chemokines and cytokines. MMPs participation in cancer progression makes them an attractive target for cancer therapy. MMPs have also been used for theranostic purposes in the detection of primary tumor and metastatic tissue in which a particular MMP is overexpressed, to follow up on therapy responses, and in the activation of cancer cytotoxic pro-drugs as part of nano-delivery-systems that increase drug concentration in a specific tumor target. Herein, we review MMPs molecular characteristics, their synthesis regulation and enzymatic activity, their participation in the metastatic process, and how their functions have been used to improve cancer treatment.

Rational Design of Cancer Nanomedicine for Simultaneous Stealth Surface and Enhanced Cellular Uptake

Owing to the complex and still not fully understood physiological environment, the development of traditional nanosized drug delivery systems is very challenging for precision cancer therapy. It is very difficult to control the in vivo distribution of nanoparticles after intravenous injection. The ideal drug nanocarriers should not only have stealth surface for prolonged circulation time but also possess enhanced cellular internalization in tumor sites. Unfortunately, the stealth surface and enhanced cellular uptake seem contradictory to each other. How to integrate the two opposite aspects into one system is a very herculean but meaningful task. As an alternative drug delivery strategy, chameleon-like drug delivery systems were developed to achieve long circulation time while maintaining enhanced cancer cell uptake. Such drug nanocarriers can "turn off" their internalization ability during circulation. However, the enhanced cellular uptake can be readily activated upon arriving at tumor tissues. In this way, stealth surface and enhanced uptake are of dialectical unity in drug delivery. In this review, we focus on the surface engineering of drug nanocarriers to obtain simultaneous stealth surfaces in circulation and enhanced uptake in tumors. The current strategies and ongoing developments, including programmed tumor-targeting strategies and some specific zwitterionic surfaces, will be discussed in detail.

Matrix Metalloproteinase-9 (MMP-9) as a Cancer Biomarker and MMP-9 Biosensors: Recent Advances

As one of the most widely investigated matrix metalloproteinases (MMPs), MMP-9 is a significant protease which plays vital roles in many biological processes. MMP-9 can cleave many extracellular matrix (ECM) proteins to regulate ECM remodeling. It can also cleave many plasma surface proteins to release them from the cell surface. MMP-9 has been widely found to relate to the pathology of cancers, including but not limited to invasion, metastasis and angiogenesis. Some recent research evaluated the value of MMP-9 as biomarkers to various specific cancers. Besides, recent research of MMP-9 biosensors discovered various novel MMP-9 biosensors to detect this enzyme. In this review, some recent advances in exploring MMP-9 as a biomarker in different cancers are summarized, and recent discoveries of novel MMP-9 biosensors are also presented.

Screening for the selective inhibitors of MMP-9 from natural products based on pharmacophore modeling and molecular docking in combination with bioassay experiment, hybrid QM/MM calculation, and MD simulation

Matrix metalloproteinase-9 (MMP-9) has been considered as an attractive target involving cancer therapy. In this study, the 3D QSAR pharmacophore model of MMP-9 inhibitors is built, and its reliability is subsequently validated based on different methods. The built pharmacophore model consists of the four chemical features, including two hydrogen bond acceptors (HBA), one hydrophobic (HY), and one ring aromatic (RA). Among them, both HY and RA are found to be especially important features because they involve the interactions of inhibitors with the S1' pocket of MMP-9, which determines the selectivity of MMP-9 inhibitors. By combining pharmacophore model with molecular docking, the virtual screening is carried out to identify the selective MMP-9 inhibitors from natural products. The four potential selective MMP-9 inhibitors of natural products are found. One of them was used to carry out the bioassay experiment inhibiting MMP-9, and the estimated IC₅₀ value of only 26.94 µM clearly shows its strongly inhibitory activity; besides, both the hybrid quantum mechanics/molecular mechanics (QM/MM) calculation and the molecular dynamics simulation are performed to examine the reliability regarding the binding mode of this inhibitor with MMP-9 active sites predicted by molecular docking. All the screened four natural products are found to well bind with the MMP-9 active sites by different kinds of interactions. Finally, the ADMET properties of screened four natural products are assessed. These screened MMP-9 inhibitors of natural products could be used as the lead compounds to perform structural modifications and optimizations in the future work. Communicated by Ramaswamy H. Sarma.

Effects of radiation on the metastatic process

Radiotherapy remains one of the corner stones in the treatment of various malignancies and often leads to an improvement in overall survival. Nonetheless, pre-clinical evidence indicates that radiation can entail pro-metastatic effects via multiple pathways. Via direct actions on cancer cells and indirect actions on the tumor microenvironment, radiation has the potential to enhance epithelial-to-mesenchymal transition, invasion, migration, angiogenesis and metastasis. However, the data remains ambiguous and clinical observations that unequivocally prove these findings are lacking. In this review we discuss the pre-clinical and clinical data on the local and systemic effect of irradiation on the metastatic process with an emphasis on the molecular pathways involved.

THE STUDY OF THE LEVELS OF METALLOPROTEINASES, CYTOKINES AND LYMPHOCYTE ACTIVATION MARKERS IN SEMINAL PLASMA OF MEN, DEPENDING ON FERTILITY

The study of the concentration of metalloproteinases, pro- and anti-inflammatory cytokines, lymphocyte activation markers in seminal plasma of men with oligosymptomatic forms of chronic inflammation of the urogenital tract (CIUT), depending on the fertility rate are presented in the article. Quantitative characteristics in male sperm with different forms of pathospermia were studied for matrix metalloproteinases (MMP) -2 and MMP-9 and their inhibitors - tissue inhibitors of metalloproteinases (TIMP)-1 and TIMP-2. It was shown, that during chronic inflammation of the urogenital tract of men are shifting levels of cytokine profile, reducing the concentration of metalloproteinase-2, chemokines - fractalkine and regulated by activation, expression and secretion of normal T-cells (RANTES), sharp increase in IL-8, MCP-1 and elevation of the CD25+ / CD95+, indicating that the disturbance of apoptosis of pathological forms generative cells and their accumulation in the sperm. The ratio of immunological indices IL-2/IL-4, IL-10/IL-12 was calculated and a significant increase in the IL-10/IL-12 index was noted in the group of individuals with elevated levels of hypercapitated form of sperm, and a reduced proportion of this ratio was observed in the microsomatic morphology of sperm. Prolonged inflammation in the genital area accompanied by depletion of the local immune system, resulting in the development of infertility. Immunocorrection therapy for men with CIUT should take into account the peculiarities of changes in local immunity and be differentiated depending on the prevalence of certain pathological forms of sperm and changes in the cytokine profile of the seminal plasma.

Early changes in the apparent diffusion coefficient and MMP-9 expression of a cervical carcinoma U14 allograft model following irradiation

A cervical carcinoma allograft model was designed to assess the correlation between early changes in the apparent diffusion coefficient (ADC) values on diffusion-weighted magnetic resonance imaging (DW-MRI) and the expression of matrix metalloproteinase-9 (MMP-9) in tumors. BALB/c mice with U14 tumor allografts on the right rear flank were irradiated with a single 20 Gy dose. All tumor-bearing mice were subjected to DW-MRI, followed by calculation of the ADC values and characterization of the T1 and T2 relaxation time constants. Pre- and post-irradiation ADC values were compared with the tumor volume, and the immunohistochemical staining of MMP-9 and hematoxylin-eosin (HE) staining of tumor allografts. However, no correlations between the pre-treatment ADC values and changes in tumor volumes following irradiation were observed. Notably, the mean ADC value was significantly higher in the irradiated tumors (0.756±0.102×10^-3 mm²/sec) as compared with those in the untreated tumors (0.501±0.052×10^-3 mm²/sec; P=0.002; r=0.682). Additionally, immunohistochemical staining demonstrated that MMP-9 expression in the irradiated tumors was significantly increased. The mean ADC value was significantly higher in the irradiated tumors with high MMP-9 expression levels (0.815±0.112×10^-3 mm²/sec), as compared with in the untreated tumors with low MMP-9 expression levels (0.631±0.068×10^-3 mm²/sec). Quantitative analysis determined that the ADC values were correlated with MMP-9 expression (r=0.752; P=0.003). Combined, these results suggest that radiation-induced increases in MMP-9 expression levels may be responsible for early changes in the mean ADC value and the response to irradiation in cervical carcinoma.

Differential response to ablative ionizing radiation in genetically distinct non-small cell lung cancer cells

Stereotactic ablative radiotherapy (SABR) has emerged as a highly promising treatment for medically inoperable early-stage non-small cell lung cancer patients. Treatment outcomes after SABR have been excellent compared to conventional fractionated radiotherapy (CFRT). However, the biological determinants of the response to ablative doses of radiation remain poorly characterized. Furthermore, there's little data on the cellular and molecular response of genetically distinct NSCLC subtypes to radiation. We assessed the response of 3 genetically distinct lung adenocarcinoma cell lines to ablative and fractionated ionizing radiation (AIR and FIR). We studied clonogenic survival, cell proliferation, migration, invasion, apoptosis and senescence. We also investigated the effect of AIR and FIR on the expression of pro-invasive proteins, epithelial-to-mesenchymal transition (EMT), extracellular signal-regulated kinases (ERK1/2) and the transmembrane receptor cMET. Our findings reveal that AIR significantly reduced cell proliferation and clonogenic survival compared to FIR in A549 cells only. This differential response was not observed in HCC827 or H1975 cells. AIR significantly enhanced the invasiveness of A549 cells, but not HCC827 or H1975 cells compared to FIR. Molecular analysis of pathways involved in cell proliferation and invasion revealed that AIR significantly reduced phosphorylation of ERK1/2 and upregulated cMET expression in A549 cells. Our results show a differential proliferative and invasive response to AIR that is dependent on genetic subtype and independent of intrinsic radioresistance. Further examination of these findings in a larger panel of NSCLC cell lines and in pre-clinical models is warranted for identification of biomarkers of tumor response to AIR.

Dual Enzymatic Reaction-Assisted Gemcitabine Delivery Systems for Programmed Pancreatic Cancer Therapy

Dual enzymatic reactions were introduced to fabricate programmed gemcitabine (GEM) nanovectors for targeted pancreatic cancer therapy. Dual-enzyme-sensitive GEM nanovectors were prepared by conjugation of matrix metalloproteinase-9 (MMP-9) detachable poly(ethylene glycol) (PEG), cathepsin B-cleavable GEM, and targeting ligand CycloRGD to CdSe/ZnS quantum dots (QDs). The GEM nanovectors decorated with a PEG corona could avoid nonspecific interactions and exhibit prolonged blood circulation time. After GEM nanovectors were accumulated in tumor tissue by the enhanced permeability and retention (EPR) effect, the PEG corona can be removed by overexpressed MMP-9 in tumor tissue and RGD would be exposed, which was capable of facilitating cellular internalization. Once internalized into pancreatic cancer cells, the elevated lysosomal cathepsin B could further promote the release of GEM. By employing dual enzymatic reactions, the GEM nanovectors could achieve prolonged circulation time while maintaining enhanced cellular internalization and effective drug release. The proposed mechanism of the dual enzymatic reaction-assisted GEM delivery system was fully investigated both in vitro and in vivo. Meanwhile, compared to free GEM, the deamination of GEM nanovectors into inactive 2',2'-difluorodeoxyuridine (dFdU) could be greatly suppressed, while the concentration of the activated form of GEM (gemcitabine triphosphate, dFdCTP) was significantly increased in tumor tissue, thus exhibiting superior tumor inhibition activity with minimal side effects.

NF‑κB inhibition is associated with OPN/MMP‑9 downregulation in cutaneous melanoma

The development of cutaneous melanoma is influenced by genetic factors, including BRAF mutations and environmental factors, such as ultraviolet exposure. Its progression has been also associated with the involvement of several tumour microenvironmental molecules. Among these, nuclear factor‑κB (NF‑κB) has been indicated as a key player of osteopontin (OPN) and matrix metalloproteinase‑9 (MMP‑9) activation. However, whether NF‑κB plays a role in the development and progression of melanoma in association with the OPN/MMP‑9 axis according to the BRAFV600E mutation status has not been investigated in detail to date. Thus, in the present study, in order to shed light on this matter, 148 patients with melanoma and 53 healthy donors were recruited for the analysis of OPN, MMP‑9 and NF‑κB. Significantly higher circulating levels of OPN and MMP‑9 were observed in the patients with melanoma when compared to the healthy donors. Similar data were obtained for NF‑κB p65 activity. The OPN levels did not differ significantly between melanomas with or without BRAFV600E mutation. However, as regards NF‑κB and MMP‑9, significant differences were observed between the melanomas with or without BRAFV600E mutation. To determine whether NF‑κB inhibition is associated with a decrease in the levels of OPN and MMP‑9, peripheral blood mononuclear cells from 29 patients with melanoma were treated with the NF‑κB inhibitor, dehydroxymethylepoxyquinomycin (DHMEQ), with or without OPN. As expected, the inhibition of NF‑κB induced a marked decrease in both the OPN and MMP‑9 levels. Furthermore, the decrease in MMP‑9 levels was higher among melanomas harbouring the BRAFV600E mutation. Overall, our data suggest that the activation of MMP‑9 is associated with the BRAFV600E mutation status. Furthermore, such an activation is mediated by NF‑κB, suggesting its role as therapeutic target in patients with melanoma.

Induction of metastasis, cancer stem cell phenotype, and oncogenic metabolism in cancer cells by ionizing radiation

Radiation therapy is one of the major tools of cancer treatment, and is widely used for a variety of malignant tumours. Radiotherapy causes DNA damage directly by ionization or indirectly via the generation of reactive oxygen species (ROS), thereby destroying cancer cells. However, ionizing radiation (IR) paradoxically promotes metastasis and invasion of cancer cells by inducing the epithelial-mesenchymal transition (EMT). Metastasis is a major obstacle to successful cancer therapy, and is closely linked to the rates of morbidity and mortality of many cancers. ROS have been shown to play important roles in mediating the biological effects of IR. ROS have been implicated in IR-induced EMT, via activation of several EMT transcription factors—including Snail, HIF-1, ZEB1, and STAT3—that are activated by signalling pathways, including those of TGF-β, Wnt, Hedgehog, Notch, G-CSF, EGFR/PI3K/Akt, and MAPK. Cancer cells that undergo EMT have been shown to acquire stemness and undergo metabolic changes, although these points are debated. IR is known to induce cancer stem cell (CSC) properties, including dedifferentiation and self-renewal, and to promote oncogenic metabolism by activating these EMT-inducing pathways. Much accumulated evidence has shown that metabolic alterations in cancer cells are closely associated with the EMT and CSC phenotypes; specifically, the IR-induced oncogenic metabolism seems to be required for acquisition of the EMT and CSC phenotypes. IR can also elicit various changes in the tumour microenvironment (TME) that may affect invasion and metastasis. EMT, CSC, and oncogenic metabolism are involved in radioresistance; targeting them may improve the efficacy of radiotherapy, preventing tumour recurrence and metastasis. This study focuses on the molecular mechanisms of IR-induced EMT, CSCs, oncogenic metabolism, and alterations in the TME. We discuss how IR-induced EMT/CSC/oncogenic metabolism may promote resistance to radiotherapy; we also review efforts to develop therapeutic approaches to eliminate these IR-induced adverse effects.

Radiation-induced lung metastasis development is MT1-MMP-dependent in a triple-negative breast cancer mouse model

Background:

The prognosis of triple-negative breast cancer (TNBC) is still difficult to establish. Some TNBC benefit from radiotherapy (RT) and are cured, while in other patients metastases appear during the first 3 years after treatment. In this study, an animal model of TNBC was used to determine whether the expression of the cell membrane protease MT1-MMP in cancer cells was associated with radiation-stimulated development of lung metastases.

Methods:

Using invasion chambers, irradiated fibroblasts were used as chemoattractants to assess the invasiveness of TNBC D2A1 cell lines showing downregulated expression of MT1-MMP, which were compared with D2A1-wt (wild-type) and D2A1 shMT1-mock (empty vector) cell lines. In a mouse model, a mammary gland was irradiated followed by the implantation of the downregulated MT1-MMP D2A1, D2A1-wt or D2A1 shMT1-mock cell lines. Migration of D2A1 cells in the mammary gland, number of circulating tumour cells and development of lung metastases were assessed.

Results:

The reduction of MT1-MMP expression decreased the invasiveness of D2A1 cells and blocked the radiation enhancement of cancer cell invasion. In BALB/c mice, irradiation of the mammary gland has stimulated the invasion of cancer cells, which was associated with a higher number of circulating tumour cells and of lung metastases. These adverse effects of radiation were prevented by downregulating the MT1-MMP.

Conclusions:

This study shows that the MT1-MMP is necessary for the radiation enhancement of lung metastasis development, and that its expression level and/or localisation could be evaluated as a biomarker for predicting the early recurrence observed in some TNBC patients.

Induction of interleukin-1β by mouse mammary tumor irradiation promotes triple negative breast cancer cells invasion and metastasis development

PURPOSE

Radiotherapy increases the level of inflammatory cytokines, some of which are known to promote metastasis. In a mouse model of triple negative breast cancer (TNBC), we determined whether irradiation of the mammary tumor increases the level of key cytokines and favors the development of lung metastases.

MATERIALS AND METHODS

D2A1 TNBC cells were implanted in the mammary glands of a Balb/c mouse and then 7 days old tumors were irradiated (4 × 6 Gy). The cytokines IL-1β, IL-4, IL-6, IL-10, IL-17 and MIP-2 were quantified in plasma before, midway and after irradiation. The effect of tumor irradiation on the invasion of cancer cells, the number of circulating tumor cells (CTC) and lung metastases were also measured.

RESULTS

TNBC tumor irradiation significantly increased the plasma level of IL-1β, which was associated with a greater number of CTC (3.5-fold) and lung metastases (2.3-fold), compared to sham-irradiated animals. Enhancement of D2A1 cell invasion in mammary gland was associated with an increase of the matrix metalloproteinases-2 and -9 activity (MMP-2, -9). The ability of IL-1β to stimulate the invasiveness of irradiated D2A1 cells was confirmed by in vitro invasion chamber assays.

CONCLUSION

Irradiation targeting a D2A1 tumor and its microenvironment increased the level of the inflammatory cytokine IL-1β and was associated with the promotion of cancer cell invasion and lung metastasis development.

Thymocyte development in the absence of matrix metalloproteinase-9/gelatinase B

Matrix metalloproteinases (MMP) play critical roles in a variety of immune reactions by facilitating cell migration, and affect cell communication by processing both cytokines and cell surface receptors. Based on published data indicating that MMP-9 is upregulated upon T cell activation and also in the thymus upon the induction of negative selection, we investigated the contribution of MMP-9 into mouse T cell development and differentiation in the thymus. Our data suggest that MMP-9 deficiency does not result in major abnormalities in the development of any conventionally selected or agonist selected subsets and does not interfere with thymocyte apoptosis and clearance, and that MMP-9 expression is not induced in immature T cells at any stage of their thymic development.

Tumor cell intravasation

The process of entering the bloodstream, intravasation, is a necessary step in the development of distant metastases. The focus of this review is on the pathways and molecules that have been identified as being important based on current in vitro and in vivo assays for intravasation. Properties of the vasculature which are important for intravasation include microvessel density and also diameter of the vasculature, with increased intravasation correlating with increased vessel diameter in some tumors. TGFB signaling can enhance intravasation at least in part through induction of EMT, and we discuss other TGFB target genes that are important for intravasation. In addition to TGFB signaling, a number of studies have demonstrated that activation of EGF receptor family members stimulates intravasation, with downstream signaling through PI3K, N-WASP, RhoA, and WASP to induce invadopodia. With respect to proteases, there is strong evidence for contributions by uPA/uPAR, while the roles of MMPs in intravasation may be more tumor specific. Other cells including macrophages, fibroblasts, neutrophils, and platelets can also play a role in enhancing tumor cell intravasation. The technology is now available to interrogate the expression patterns of circulating tumor cells, which will provide an important reality check for the model systems being used. With a better understanding of the mechanisms underlying intravasation, the goal is to provide new opportunities for improving prognosis as well as potentially developing new treatments.

Development and Characterization of an Inducible Rat Model of Chronic Thromboembolic Pulmonary Hypertension

Chronic thromboembolic pulmonary hypertension (CTEPH) is an entity of PH that not only limits patients quality of life but also causes significant morbidity and mortality. The treatment of choice is pulmonary endarterectomy. However numerous patients do not qualify for pulmonary endarterectomy or present with residual vasculopathy post pulmonary endarterectomy and require specific vasodilator treatment. Currently, there is no available specific small animal model of CTEPH that could serve as tool to identify targetable molecular pathways and to test new treatment options. Thus, we generated and standardized a rat model that not only resembles functional and histological features of CTEPH but also emulates thrombi fibrosis. The pulmonary embolism protocol consisted of 3 sequential tail vein injections of fibrinogen/collagen-covered polystyrene microspheres combined with thrombin and administered to 10-week-old male Wistar rats. After the third embolism, rats developed characteristic features of CTEPH including elevated right ventricular systolic pressure, right ventricular cardiomyocyte hypertrophy, pulmonary artery remodeling, increased serum brain natriuretic peptide levels, thrombi fibrosis, and formation of pulmonary cellular-fibrotic lesions. The current animal model seems suitable for detailed study of CTEPH pathophysiology and permits preclinical testing of new pharmacological therapies against CTEPH.

Radiation-induced pulmonary injury accelerated pulmonary metastasis in a mouse model of breast cancer

The aim of the present study was to investigate the acceleration of pulmonary metastasis due to pulmonary injury caused by radiation treatment in a mouse model of breast cancer, in addition to determining the associated mechanism. The passive metastatic breast cancer model was used in radiation-treated BALB/c mice. In total, 24 mice were randomly separated into two groups, with 12 mice per group, and the groups were treated with or without pulmonary radiation. The survival time and variation of the weights of the lungs, spleen and liver were recorded. Lung metastasis was also evaluated, and chemokine (C-X-C motif) ligand 12 (CXCL12)/chemokine (C-X-C motif) receptor 4 (CXCR4) expression was determined. The results revealed that the group with radiation-induced pulmonary injury exhibited an increased incidence of pulmonary metastasis and shorter survival time compared with the mice without pulmonary radiation. The radiation-treated group possessed an increased number of metastatic nodules in the lungs, but metastasis was not evident in the liver and spleen. The CXCL12/CXCR4 axis was markedly expressed and the expression was significantly increased subsequent to radiation compared with the expression in normal lung tissues. The present study demonstrated that radiation-induced pulmonary injury may accelerate metastatic tumor growth and decrease the overall survival rate of the mice following in situ injection of tumor cells. Tumor localization and growth may have been favored by metastatic conditioning in the lung subsequent to radiotherapy. The CXCL12/CXCR4 axis may affect key elements in the multistep process of metastasis induced by radiation injury.

Radiotherapy treatment of adrenal gland metastases from hepatocellular carcinoma: clinical features and prognostic factors

Background

The optimal treatment for adrenal metastases from hepatocellular carcinoma (HCC) has not been established. This study analyzed the effects of radiation therapy (RT) for such metastases and identified clinical features and predictors of survival in these patients.

Methods

We retrospectively investigated 55 patients with adrenal metastasis from HCC who had been treated with RT. Radiation doses to the adrenal lesions ranged from 26 to 60 Gy, while the intrahepatic lesions were treated by surgical resection, transarterial chemoembolization (TACE), liver transplantation, and/or RT. RT was conducted to adrenal lesions after their intrahepatic lesions were controlled more than 2 months. The parameters studied included survival rates and tumor responses to RT. The Kaplan-Meier method was used to evaluate survival rate and the Cox regression model was used to identify potential predictors of outcome.

Results

The patients treated by RT had adrenal metastasis on the right side (41), the left (6), or on both sides (8). In all 55 patients, the median survival duration was 13.6 months and there was 100% pain relief after completion of RT. Adverse effects were mild to moderate. Unfavorable pretreatment predictors determined by univariate analysis were associated with multiple intrahepatic foci, metastases to additional organs, high γ-glutamyltransferase and alpha-fetoprotein levels, liver function of Child-Pugh classification B and uncontrolled primary HCC. By multivariate analysis, unfavorable predictors were multiple intrahepatic foci, metastases to additional organs and uncontrolled primary HCC.

Conclusions

Radiotherapy as treatment for adrenal metastases in HCC is a good palliative therapy that is associated with reasonable safety. It appears reasonable that such patients should be considered to be treated with radiotherapy. Multiple intrahepatic foci, metastases to additional organs and uncontrolled primary HCC were unfavorable predictors.

Radiation oncology in vitro: trends to improve radiotherapy through molecular targets

Much has been investigated to improve the beneficial effects of radiotherapy especially in that case where radioresistant behavior is observed. Beyond simple identification of resistant phenotype the discovery and development of specific molecular targets have demonstrated therapeutic potential in cancer treatment including radiotherapy. Alterations on transduction signaling pathway related with MAPK cascade are the main axis in cancer cellular proliferation even as cell migration and invasiveness in irradiated tumor cell lines; then, for that reason, more studies are in course focusing on, among others, DNA damage enhancement, apoptosis stimulation, and growth factors receptor blockages, showing promising in vitro results highlighting molecular targets associated with ionizing radiation as a new radiotherapy strategy to improve clinical outcome. In this review we discuss some of the main molecular targets related with tumor cell proliferation and migration as well as their potential contributions to radiation oncology improvements.

Radiation-enhanced cell migration/invasion process: a review

Radiation therapy is a keystone treatment in cancer. Photon radiation has proved its benefits in overall survival in many clinical studies. However, some patients present local recurrences or metastases when cancer cells survive to treatment. Metastasis is a process which includes adhesion of the cell to the extracellular matrix, degradation of the matrix by proteases, cell motility, intravasation in blood or lymphatic vessels, extravasation in distant parenchyma and development of cell colonies. Several studies demonstrated that ionizing radiation might promote migration and invasion of tumor cells by intricate implications in the micro-environment, cell-cell junctions, extracellular matrix junctions, proteases secretion, and induction of epithelial-mesenchymal transition. This review reports various cellular pathways involved in the photon-enhanced cell invasion process for which potential therapeutic target may be employed for enhancing antitumor effectiveness. Understanding these mechanisms could lead to therapeutic strategies to counter the highly invasive cell lines via specific inhibitors or carbon-ion therapy.

Filamin A interacting protein 1-like inhibits WNT signaling and MMP expression to suppress cancer cell invasion and metastasis

Identifying key mediators of cancer invasion and metastasis is crucial to the development of new and more effective therapies. We previously identified FILamin A Interacting Protein 1-Like (FILIP1L) as an important inhibitor of cell migration and invasion. FILIP1L expression was inversely correlated with the invasive potential of ovarian tumors. In our study, we established an orthotopic ovarian cancer model, wherein FILIP1L expression can be regulated in vivo. Using this model, we observed that expression of FILIP1L in ovarian cancer cells inhibited spontaneous lung metastasis. Experimental lung metastases (established via tail vein injection of cancer cells) as well as the extravasation step of metastasis were not inhibited by FILIP1L, suggesting that FILIP1L inhibits the earlier steps of metastasis such as invasion and intravasation. FILIP1L inhibited matrix metalloproteinase (MMP)-dependent invasion in vivo. MMP3, -7 and -9 were transcriptionally downregulated, and MMP9 protein expression and activity were inhibited in FILIP1L-expressing tumors. Importantly, overexpression of MMP9 compensated for the anti-invasive activity of FILIP1L. Furthermore, our studies suggest that FILIP1L regulates invasion and metastasis by inhibiting components of the WNT signaling pathway. FILIP1L expression reduced the induction of WNT target genes such as MMP3, -7 and -9, and β-catenin-directed transcriptional activity, suggesting inhibition of the canonical WNT pathway. Nuclear β-catenin, an indicator of an active canonical WNT pathway, was reduced in FILIP1L-expressing tumors. Overall, these findings suggest that FILIP1L reduces β-catenin levels, which may lead to the transcriptional downregulation of WNT target genes such as MMPs, resulting in inhibition of metastasis. Modulation of FILIP1L expression has the potential to be a target for cancer therapy.

Characterization of H460R, a Radioresistant Human Lung Cancer Cell Line, and Involvement of Syntrophin Beta 2 (SNTB2) in Radioresistance

A radioresistant cell line was established by fractionated ionizing radiation (IR) and assessed by a clonogenic assay, flow cytometry, and Western blot analysis, as well as zymography and a wound healing assay. Microarray was performed to profile global expression and to search for differentially expressed genes (DEGs) in response to IR. H460R cells demonstrated increased cell scattering and acidic vesicular organelles compared with parental cells. Concomitantly, H460R cells showed characteristics of increased migration and matrix metalloproteinase activity. In addition, H460R cells were resistant to IR, exhibiting reduced expression levels of ionizing responsive proteins (p-p53 and γ-H2AX); apoptosis-related molecules, such as cleaved poly(ADP ribose) polymerase; and endoplasmic reticulum stress-related molecules, such as glucose-regulated protein (GRP78) and C/EBP-homologous protein compared with parental cells, whereas the expression of anti-apoptotic X-linked inhibitor of apoptosis protein was increased. Among DEGs, syntrophin beta 2 (SNTB2) significantly increased in H460R cells in response to IR. Knockdown of SNTB2 by siRNA was more sensitive than the control after IR exposure in H460, H460R, and H1299 cells. Our study suggests that H460R cells have differential properties, including cell morphology, potential for metastasis, and resistance to IR, compared with parental cells. In addition, SNTB2 may play an important role in radioresistance. H460R cells could be helpful in in vitro systems for elucidating the molecular mechanisms of and discovering drugs to overcome radioresistance in lung cancer therapy.

Early detection of Lewis lung carcinoma tumor control by irradiation using diffusion-weighted and dynamic contrast-enhanced MRI

PURPOSE

To investigate the correlation between diffusion-weighted (DW) and dynamic contrast-enhanced (DCE) magnetic resonance imaging (MRI) derived parameters and radioresponsiveness of Lewis lung carcinoma (LLC) tumor.

MATERIALS AND METHODS

LLC tumor growth in C57BL/6 mouse limb was used for the experiment. The tumors were irradiated with 10 Gy×5, or 30 Gy×2 vs. sham irradiation. Fourteen tumors were subjected to DW-MRI and DCE-MRI pre-radiotherapy and weekly imaging after radiotherapy. The temporal changes in apparent diffusion coefficient (ADC) and DCE-MRI derived parameters (K(trans), k(ep), v(e), and v(p)) were correlated with tumor size, and were histologically compared with CD31 staining of resected tumors.

RESULTS

The 10 Gy×5 dose inhibited tumor growth for a week, while 30 Gy×2 controlled tumor growth for a 3-week observation period. One week after radiotherapy (week 2), irradiated tumors showed significantly higher values of ADC than untreated ones (10 Gy×5, p = 0.004; 30 Gy×2, p = 0.01). Significantly higher values of v(e) were shown earlier by 30 Gy×2 vs. sham (p = 0.01) and 10 Gy×5 vs. sham irradiation (p = 0.05). Sustained higher v(e) from 10 Gy×5 compared to sham irradiated tumors was evident at week 3 (p = 0.016) and week 4 (p = 0.046). A 13.8% early increase in ADC for 30 Gy×2 tumor group (p = 0.002) and a 16.5% increase for 10 Gy×5 group were noted (p = 0.01) vs. sham irradiation (which showed a 2.2% decrease). No differences were found for K(trans), k(ep), or v(p). Both radiotherapy groups demonstrated significant reduction in microvessel counts.

CONCLUSION

Early increase in ADC and v(e) correlated with tumor control by irradiation.

Expression of N-acetylgalactosamine 4-sulfate 6-O-sulfotransferase involved in chondroitin sulfate synthesis is responsible for pulmonary metastasis

Chondroitin sulfate (CS) containing E-disaccharide units, glucuronic acid-N-acetylgalactosamine(4, 6-O-disulfate), at surfaces of tumor cells plays a key role in tumor metastasis. However, the molecular mechanism of the metastasis involving the CS chain-containing E-units is not fully understood. In this study, to clarify the role of E-units in the metastasis and to search for potential molecular targets for anticancer drugs, the isolation and characterization of Lewis lung carcinoma (LLC) cells stably downregulated by the knockdown for the gene encoding N-acetylgalactosamine 4-O-sulfate 6-O-sulfotransferase (GalNAc4S-6ST), which is responsible for the formation of E-units in CS chains, were performed. Knockdown of GalNAc4S-6ST in LLC cells resulted in a reduction in the proportion of E-units, in adhesiveness to extracellular matrix adhesion molecules and in proliferation in vitro. Furthermore, the stable downregulation of GalNAc4S-6ST expression in LLC cells markedly inhibited the colonization of the lungs by inoculated LLC cells and invasive capacity of LLC cells. These results provide clear evidence that CS chain-containing E-units and/or GalNAc4S-6ST play a crucial role in pulmonary metastasis at least through the increased adhesion and the invasive capacity of LLC cells and also provides insights into future drug targets for anticancer treatment.

Biomarker studies on radiotherapy to hepatocellular carcinoma

Radiotherapy (RT) has been gradually integrated into the multimodality treatment for hepatocellular carcinoma (HCC). The various patterns of failure in HCC patients undergoing RT drive the need of effective biomarkers to guide treatment decisions. Limited numbers of biomarkers have been investigated in HCC, with even fewer of them for patients treated by RT. Serum or plasma biomarkers measured by enzyme-linked immunosorbent assay were the most common practice. Of particular interest are those biomarkers that are detectable early in the course of radiotherapy which correlated with ultimate clinical outcome. Functional magnetic resonance imaging (MRI) is increasingly used to evaluate the imaging pattern indicative of disease control following RT. Positron emission tomography shows that pre-RT standard uptake values associate with various types of recurrence after treatment. Proximity ligation assay (PLA) is evolving with the unique features of dual-probe identification, ligation and amplification to allow the small volume of serum/plasma samples for evaluating multiple biomarkers. We demonstrate the screening work of biomarkers by PLA with pre- and post-RT serum samples from HCC patients undergoing RT. Efforts are being made to search for the potential biomarkers for HCC patients treated by RT.