Mesenchymal stem cells generate pericytes to promote tumor recurrence via vasculogenesis after stereotactic body radiation therapy

Determinants of cerebral radionecrosis in animal models: A systematic review

BACKGROUND

Radionecrosis is a common complication in radiation oncology, while mechanisms and risk factors have yet to be fully explored. We therefore conducted a systematic review to understand the pathogenesis and identify factors that significantly affect the development.

METHODS

We performed a systematic literature search based on the PRISMA guidelines using PubMed, Ovid, and Web of Science databases. The complete search strategy can be found as a preregistered protocol on PROSPERO (CRD42023361662).

RESULTS

We included 83 studies, most involving healthy animals (n = 72, 86.75 %). High doses of hemispherical irradiation of 30 Gy in rats and 50 Gy in mice led repeatedly to radionecrosis among different studies and set-ups. Higher dose and larger irradiated volume were associated with earlier onset. Fractionated schedules showed limited effectiveness in the prevention of radionecrosis. Distinct anatomical brain structures respond to irradiation in various ways. White matter appears to be more vulnerable than gray matter. Younger age, more evolved animal species, and genetic background were also significant factors, whereas sex was irrelevant. Only 13.25 % of the studies were performed on primary brain tumor bearing animals, no studies on brain metastases are currently available.

CONCLUSION

This systematic review identified various factors that significantly affect the induction of radionecrosis. The current state of research neglects the utilization of animal models of brain tumors, even though patients with brain malignancies constitute the largest group receiving brain irradiation. This latter aspect should be primarily addressed when developing an experimental radionecrosis model for translational implementation.

2D MXene-Based Nanoscale Materials for Electrochemical Sensing Toward the Detection of Hazardous Pollutants: A Perspective

MXenes (Mn+1XnTx), a subgroup of 2-dimensional (2D) materials, specifically comprise transition metal carbides, nitrides, and carbonitrides. They exhibit exceptional electrocatalytic and photocatalytic properties, making them well-suited for the detection and removal of pollutants from aqueous environments. Because of their high surface area and remarkable properties, they are being utilized in various applications, including catalysis, sensing, and adsorption, to combat pollution and mitigate its adverse effects. Different characterization techniques like XRD, SEM, TEM, UV-Visible spectroscopy, and Raman spectroscopy have been used for the structural elucidation of 2D MXene. Current responses against applied potential were measured during the electrochemical sensing of the hazardous pollutants in an aqueous system using a variety of electroanalytical techniques, including differential pulse voltammetry, amperometry, square wave anodic stripping voltammetry, etc. In this review, a comprehensive discussion on structural patterns, synthesis, properties of MXene and their application for electrochemical detection of lethal pollutants like hydroquionone, phenol, catechol, mercury and lead, etc. are presented. This review will be helpful to critically understand the methods of synthesis and application of MXenes for the removal of environmental pollutants.

Prediction of induced magnetism in 2D Ti2C based MXenes by manipulating the mixed surface functionalization and metal substitution computed by xTB model Hamiltonian of the DFTB method

We employed the recently developed density functional tight binding (DFTB) method's Hamiltonian, GFN1-xTB, for modeling the mixed termination in Ti2C MXenes, namely three types of termination by combining -O and -OH, -O and -F, and -F and -OH. We demonstrated that the approach yields reliable predictions for the electronic and magnetic properties of such MXenes. The first highlighted result is that the mixed surface functionalization in Ti2CAxBy MXenes induces spin polarization with diverse magnetic alignments, including ferromagnetism and two types of antiferromagnetism. We further identified the magnetic alignment for the investigated MXene in terms of the compositions of the terminal groups. Moreover, the effect of the transition metal (Ti) substituted by the Sc atom on the electronic and magnetic properties was also investigated. We found that the studied systems maintain the magnetism and the metallic characteristics. A magnetic transition from antiferromagnetic (AFM) to ferrimagnetic (FiM) ordering was found for ScTi15C8F8(OH)8 and ScTi15C8F12(OH)4 compounds. Finally, we proved that incorporating the Sc atom into the lattice of Ti2CO2 and the mixed surface termination in Ti2CAxBy is an effective strategy to induce magnetism. Our study may provide a new potential application for designing MXene-based spintronics.

Biology and Therapeutic Properties of Mesenchymal Stem Cells in Leukemia

This comprehensive review delves into the multifaceted roles of mesenchymal stem cells (MSCs) in leukemia, focusing on their interactions within the bone marrow microenvironment and their impact on leukemia pathogenesis, progression, and treatment resistance. MSCs, characterized by their ability to differentiate into various cell types and modulate the immune system, are integral to the BM niche, influencing hematopoietic stem cell maintenance and functionality. This review extensively explores the intricate relationship between MSCs and leukemic cells in acute myeloid leukemia, acute lymphoblastic leukemia, chronic myeloid leukemia, and chronic lymphocytic leukemia. This review also addresses the potential clinical applications of MSCs in leukemia treatment. MSCs' role in hematopoietic stem cell transplantation, their antitumor effects, and strategies to disrupt chemo-resistance are discussed. Despite their therapeutic potential, the dual nature of MSCs in promoting and inhibiting tumor growth poses significant challenges. Further research is needed to understand MSCs' biological mechanisms in hematologic malignancies and develop targeted therapeutic strategies. This in-depth exploration of MSCs in leukemia provides crucial insights for advancing treatment modalities and improving patient outcomes in hematologic malignancies.

Incorporating Stereotactic Ablative Radiotherapy into the Multidisciplinary Management of Renal Cell Carcinoma

Stereotactic ablative radiotherapy (SABR) has challenged the conventional wisdom surrounding the radioresistance of renal cell carcinoma (RCC). In the past decade, there has been a significant accumulation of clinical data to support the safety and efficacy of SABR in RCC. Herein, we review the use of SABR across the spectrum of RCC. We performed an online search of the Pubmed database from January 1990 through April 2023. Studies of SABR/stereotactic radiosurgery targeting primary, extracranial, and intracranial metastatic RCC were included. For SABR in non-metastatic RCC, this includes its use in small renal masses, larger renal masses, and inferior vena cava tumor thrombi. In the metastatic setting, SABR can be used at diagnosis, for oligometastatic and oligoprogressive disease, and for symptomatic reasons. Notably, SABR can be used for both the primary renal tumor and metastasis-directed therapy. Management of RCC is evolving rapidly, and the role that SABR will have in this landscape is being assessed in a number of ongoing prospective clinical trials. The objective of this narrative review is to summarize the evidence corroborating the use of SABR in RCC.

New advances in the research of clinical treatment and novel anticancer agents in tumor angiogenesis

In 1971, Folkman proposed that tumors could be limited to very small sizes by blocking angiogenesis. Angiogenesis is the generation of new blood vessels from pre-existing vessels, considered to be one of the important processes in tumor growth and metastasis. Angiogenesis is a complex process regulated by various factors and involves many secreted factors and signaling pathways. Angiogenesis is important in the transport of oxygen and nutrients to the tumor during tumor development. Therefore, inhibition of angiogenesis has become an important strategy in the clinical management of many solid tumors. Combination therapies of angiogenesis inhibitors with radiotherapy and chemotherapy are often used in clinical practice. In this article, we will review common targets against angiogenesis, the most common and up-to-date anti-angiogenic drugs and clinical treatments in recent years, including active ingredients from chemical and herbal medicines.

Inhibition of CXCR4 Enhances the Efficacy of Radiotherapy in Metastatic Prostate Cancer Models

Radiotherapy (RT) is a standard treatment for patients with advanced prostate cancer (PCa). Previous preclinical studies showed that SDF1α/CXCR4 axis could mediate PCa metastasis (most often to the bones) and cancer resistance to RT. We found high levels of expression for both SDF1α and its receptor CXCR4 in primary and metastatic PCa tissue samples. In vitro analyses using PCa cells revealed an important role of CXCR4 in cell invasion but not radiotolerance. Pharmacologic inhibition of CXCR4 using AMD3100 showed no efficacy in orthotopic primary and bone metastatic PCa models. However, when combined with RT, AMD3100 potentiated the effect of local single-dose RT (12 Gy) in both models. Moreover, CXCR4 inhibition also reduced lymph node metastasis from primary PCa. Notably, CXCR4 inhibition promoted the normalization of bone metastatic PCa vasculature and reduced tissue hypoxia. In conclusion, the SDF1α/CXCR4 axis is a potential therapeutic target in metastatic PCa patients treated with RT.

Electronic Nature Transition and Magnetism Creation in Vacancy-Defected Ti2CO2 MXene under Biaxial Strain: A DFTB + U Study

The structural, electronic, and magnetic properties of vacancy defect in Ti₂CO₂ MXene and the effect of strain have been investigated using the density functional tight-binding (DFTB) approach including spin-polarization with Hubbard onsite correction (DFTB + U). The band gap of pure Ti₂CO₂ is ∼1.3 eV, which decreases to ∼0.4 and ∼1.1 eV in the case of C- and O-vacancies, respectively, i.e., the semiconducting behavior is retained. In contrast, Ti₂CO₂ undergoes semiconductor-to-metal transition by the introduction of a single Ti-vacancy. This transition is the result of introduced localized states in the vicinity of the Fermi level by the vacancy. Both Ti- and O-vacancies have zero net magnetic moments. Interestingly, the nonmagnetic (NM) ground state of semiconducting Ti₂CO₂ turns into a magnetic semiconductor by introducing a C-vacancy with a magnetization of ∼2 μ_B/cell. Furthermore, we studied the effect of strain on the electronic structure and magnetic properties of Ti-, C-, and O-vacant Ti₂CO₂. The nature of the band gap in the presence of single O-vacancy remains indirect in both compression and tensile strain, and the size of the band gap decreases. Compression strain on Ti-vacant Ti₂CO₂ changes metal into a direct semiconductor, and the metallic character remains under tensile biaxial strain. In opposition, a semiconductor-to-metal transition occurs by applying a compressive biaxial strain on C-vacant Ti₂CO₂. We also find that the magnetism is preserved under tensile strain and suppressed under compression strain on V_C-Ti₂CO₂. Moreover, we show that double C-vacancies maintain magnetism. Our findings provide important characteristics for the application of the most frequent MXene material and should motivate further investigations because experimentally achieved MXenes always contain point defects.

TA-MSCs, TA-MSCs-EVs, MIF: their crosstalk in immunosuppressive tumor microenvironment

As an important component of the immunosuppressive tumor microenvironment (TME), it has been established that mesenchymal stem cells (MSCs) promote the progression of tumor cells. MSCs can directly promote the proliferation, migration, and invasion of tumor cells via cytokines and chemokines, as well as promote tumor progression by regulating the functions of anti-tumor immune and immunosuppressive cells. MSCs-derived extracellular vesicles (MSCs-EVs) contain part of the plasma membrane and signaling factors from MSCs; therefore, they display similar effects on tumors in the immunosuppressive TME. The tumor-promoting role of macrophage migration inhibitory factor (MIF) in the immunosuppressive TME has also been revealed. Interestingly, MIF exerts similar effects to those of MSCs in the immunosuppressive TME. In this review, we summarized the main effects and related mechanisms of tumor-associated MSCs (TA-MSCs), TA-MSCs-EVs, and MIF on tumors, and described their relationships. On this basis, we hypothesized that TA-MSCs-EVs, the MIF axis, and TA-MSCs form a positive feedback loop with tumor cells, influencing the occurrence and development of tumors. The functions of these three factors in the TME may undergo dynamic changes with tumor growth and continuously affect tumor development. This provides a new idea for the targeted treatment of tumors with EVs carrying MIF inhibitors.

The safety and efficacy of mesenchymal stem cell therapy in diabetic lower extremity vascular disease: a meta-analysis and systematic review

BACKGROUND AIMS

Several studies have shown the efficacy of mesenchymal stem cell (MSC) therapy for lower extremity vascular disease (LEVD) in diabetic patients, but the results are not consistent. Therefore, the authors conducted a meta-analysis of randomized controlled trials (RCTs) to examine the safety and efficacy of MSC therapy in diabetic patients with LEVD.

METHODS

Eight available databases were searched in both English and Chinese to identify RCTs comparing MSC therapy-based conventional treatment with conventional treatment alone in diabetic patients with LEVD. Three investigators independently screened the literature, extracted the data and assessed the risk bias. Meta-analysis was performed using RevMan 5.4.1 and Stata 14.0.

RESULTS

A total of 10 studies involving 453 patients were included. Compared with conventional treatment only, patients receiving MSC therapy-based conventional treatment had a higher ulcer healing rate, greater number of reduced ulcers and shorter complete healing time. MSC therapy also increased ankle-brachial index and transcutaneous oxygen pressure. In addition, four of the included studies showed that MSC therapy significantly improved the number of new collateral vessels. Moreover, no more adverse events were recorded in the MSC group.

CONCLUSIONS

This meta-analysis suggests that MSC therapy promotes ulcer healing in diabetic LEVD patients with ulcers, improves blood supply and has a favorable safety profile. More large and well-designed RCTs with long-term follow-up are still needed to explore the safety and efficacy of MSC therapy in diabetic patients with LEVD.

Salvage therapy for prostate cancer after radical prostatectomy

More than 40% of men with intermediate-risk or high-risk prostate cancer will experience a biochemical recurrence after radical prostatectomy. Clinical guidelines for the management of these patients largely focus on the use of salvage radiotherapy with or without systemic therapy. However, not all patients with biochemical recurrence will go on to develop metastases or die from their disease. The optimal pre-salvage therapy investigational workup for patients who experience biochemical recurrence should, therefore, include novel techniques such as PET imaging and genomic analysis of radical prostatectomy specimen tissue, as well as consideration of more traditional clinical variables such as PSA value, PSA kinetics, Gleason score and pathological stage of disease. In patients without metastatic disease, the only known curative intervention is salvage radiotherapy but, given the therapeutic burden of this treatment, importance must be placed on accurate timing of treatment, radiation dose, fractionation and field size. Systemic therapy also has a role in the salvage setting, both concurrently with radiotherapy and as salvage monotherapy.

Effects of radiation on tumor vasculature

Radiation has been utilized as a direct cytotoxic tumorcidal modality, however, the effect of radiation on tumor vasculature influences response to anticancer therapies. Although numerous reports have demonstrated vascular changes in irradiated tumors, the findings and implications are extensive and at times contradictory depending on the radiation dose, timing, and models used. In this review, we focus on the radiation-mediated effects on tumor vasculature with respect to doses used, timing postradiation, vasculogenesis, adhesion molecule expression, permeability, and pericyte coverage, including the latest findings.

Lung-Resident Mesenchymal Stem Cell Fates within Lung Cancer

Simple Summary

Lung cancer remains the leading cause of cancer-related deaths worldwide. Herein, the heterogeneous tumor stroma decisively impacts on tumor progression, therapy resistance, and, thus, poor clinical outcome. Among the numerous non-epithelial cells constructing the complex environment of lung carcinomas, mesenchymal stem cells (MSC) gained attraction being stromal precursor cells that could be recruited and ‘educated’ by lung cancer cells to adopt a tumor-associated MSC phenotype, serve as source for activated fibroblasts and presumably for vascular mural cells finally reinforcing tumor progression. Lung-resident MSCs should be considered as ‘local MSCs in stand by’ ready to be arranged within the cancer stroma.

Abstract

Lung-resident mesenchymal stem cells (LR-MSCs) are non-hematopoietic multipotent stromal cells that predominately reside adventitial within lung blood vessels. Based on their self-renewal and differentiation properties, LR-MSCs turned out to be important regulators of normal lung homeostasis. LR-MSCs exert beneficial effects mainly by local secretion of various growth factors and cytokines that in turn foster pulmonary regeneration including suppression of inflammation. At the same time, MSCs derived from various tissues of origins represent the first choice of cells for cell-based therapeutic applications in clinical medicine. Particularly for various acute as well as chronic lung diseases, the therapeutic applications of exogenous MSCs were shown to mediate beneficial effects, hereby improving lung function and survival. In contrast, endogenous MSCs of normal lungs seem not to be sufficient for lung tissue protection or repair following a pathological trigger; LR-MSCs could even contribute to initiation and/or progression of lung diseases, particularly lung cancer because of their inherent tropism to migrate towards primary tumors and metastatic sites. However, the role of endogenous LR-MSCs to be multipotent tumor-associated (stromal) precursors remains to be unraveled. Here, we summarize the recent knowledge how ‘cancer-educated’ LR-MSCs impact on lung cancer with a focus on mesenchymal stem cell fates.

Identification of a Hematopoietic Cell Population Emerging From Mouse Bone Marrow With Proliferative Potential In Vitro and Immunomodulatory Capacity

There is continuing interest in therapeutic applications of bone marrow-derived mesenchymal stromal cells (MSC). Unlike human counterparts, mouse MSC are difficult to propagate in vitro due to their contamination with adherent hematopoietic cells that overgrow the cultures. Here we investigated the properties of these contaminating cells, referred to as bone marrow-derived proliferating hematopoietic cells (BM-PHC). The results showed that both BM-PHC and MSC had strong immunomodulatory properties on T cells in vitro, with PGE2 and NO involved in this mechanism. However, BM-PHC were stronger immunomodulators than MSC, with CCL-6 identified as putative molecule responsible for superior effects. In vivo studies showed that, in contrast to BM-PHC, MSC endorsed a more rapid xenograft tumor rejection, thus indicating a particular context in which only MSC therapy would produce positive outcomes. In conclusion, bone marrow contains two cell populations with immunomodulatory properties, which are valuable sources for therapeutic studies in specific disease-relevant contexts.

Angiogenesis and immune checkpoint dual blockade in combination with radiotherapy for treatment of solid cancers: opportunities and challenges

Several immune checkpoint blockades (ICBs) capable of overcoming the immunosuppressive roles of the tumor immune microenvironment have been approved by the US Food and Drug Administration as front-line treatments of various tumor types. However, due to the considerable heterogeneity of solid tumor cells, inhibiting one target will only influence a portion of the tumor cells. One way to enhance the tumor-killing efficiency is to develop a multiagent therapeutic strategy targeting different aspects of tumor biology and the microenvironment to provide the maximal clinical benefit for patients with late-stage disease. One such strategy is the administration of anti-PD1, an ICB, in combination with the humanized monoclonal antibody bevacizumab, an anti-angiogenic therapy, to patients with recurrent/metastatic malignancies, including hepatocellular carcinoma, metastatic renal cell carcinoma, non-small cell lung cancer, and uterine cancer. Radiotherapy (RT), a critical component of solid cancer management, has the capacity to prime the immune system for an adaptive antitumor response. Here, we present an overview of the most recent published data in preclinical and clinical studies elucidating that RT could further potentiate the antitumor effects of immune checkpoint and angiogenesis dual blockade. In addition, we explore opportunities of triple combinational treatment, as well as discuss the challenges of validating biomarkers and the management of associated toxicity.

Overview of Antabuse® (Disulfiram) in Radiation and Cancer Biology

Antabuse®, generic name disulfiram, has been extensively used in daily clinical practice to treat alcohol abuse. In vivo and in vitro experiments have demonstrated that disulfiram was capable of inhibiting tumor cell proliferation; clinical studies have indicated that the administration of this drug was associated with favorable survival, whilst in vitro experiments have elucidated the anticancer mechanism of disulfiram. In addition, radiation and cancer biology studies have shown that disulfiram can protect normal cells and sensitize tumor cells during radiotherapy. This review aims at describing the antitumor activity of disulfiram in both preclinical studies and clinical trials, whilst focusing on the advances of this drug in radiation and cancer biology, and the promise of repurposing it as a novel sensitizer to, and protector against, radiation on the incoming clinical studies.

Neovascularization: The Main Mechanism of MSCs in Ischemic Heart Disease Therapy

Mesenchymal stem cell (MSC) transplantation after myocardial infarction (MI) has been shown to effectively limit the infarct area in numerous clinical and preclinical studies. However, the primary mechanism associated with this activity in MSC transplantation therapy remains unclear. Blood supply is fundamental for the survival of myocardial tissue, and the formation of an efficient vascular network is a prerequisite for blood flow. The paracrine function of MSCs, which is throughout the neovascularization process, including MSC mobilization, migration, homing, adhesion and retention, regulates angiogenesis and vasculogenesis through existing endothelial cells (ECs) and endothelial progenitor cells (EPCs). Additionally, MSCs have the ability to differentiate into multiple cell lineages and can be mobilized and migrate to ischemic tissue to differentiate into ECs, pericytes and smooth muscle cells in some degree, which are necessary components of blood vessels. These characteristics of MSCs support the view that these cells improve ischemic myocardium through angiogenesis and vasculogenesis. In this review, the results of recent clinical and preclinical studies are discussed to illustrate the processes and mechanisms of neovascularization in ischemic heart disease.

Neurovascular Unit: A critical role in ischemic stroke

Ischemic stroke (IS), a common cerebrovascular disease, results from a sudden blockage of a blood vessel in the brain, thereby restricting blood supply to the area in question, and making a significantly negative impact on human health. Unfortunately, current treatments, that are mainly based on a recanalization of occluded blood vessels, are insufficient or inaccessible to many stroke patients. Recently, the profound influence of the neurovascular unit (NVU) on recanalization and the prognosis of IS have become better understood; in‐depth studies of the NVU have also provided novel approaches for IS treatment. In this article, we review the intimate connections between the changes in the NVU and IS outcomes, and discuss possible new management strategies having practical significance to IS. We discuss the concept of the NVU, as well as its roles in IS blood‐brain barrier regulation, cell preservation, inflammatory immune response, and neurovascular repair. Besides, we also summarize the influence of noncoding RNAs in NVU, and IS therapies targeting the NVU. We conclude that both the pathophysiological and neurovascular repair processes of IS are strongly associated with the homeostatic state of the NVU and that further research into therapies directed at the NVU could expand the range of treatments available for IS.

The Organ Trail: A Review of Biomarkers of Organ Failure

Pediatric organ failure and transplant populations face significant risks of morbidity and mortality. The risk of organ failure itself may be disproportionately higher among pediatric oncology patients, as cancer may originate within and/or metastasize to organs and adversely affect their function. Additionally, cancer directed therapies are frequently toxic to organs and may contribute to failure. Recent reports suggest that nearly half of providers find it difficult to provide prognostic information regarding organ failure due to unknown disease trajectories. Unfortunately, there is a lack of uniform methodology in detecting the early symptoms of organ failure, which may delay diagnosis, initiation of treatment and hinder prognostic planning. There remains a wide array of outstanding scientific questions regarding organ failure in pediatrics but emerging data may change the landscape of prognostication. Liquid biopsy, in which disease biomarkers are detected in bodily fluids, offers a noninvasive alternative to tissue biopsy and may improve prompt detection of organ failure and prognostication. Here, we review potential liquid biopsy biomarkers for organ failure, which may be particularly useful among pediatric oncology patients. We synthesized information from publications obtained on PubMed, Google Scholar, clinicaltrials.gov, and Web of Science and categorized our findings based on the type of biomarker used to detect organ failure. We highlight the advantages and disadvantages specific to each type of organ failure biomarker. While much work needs to be done to advance this field and validate its applicability to pediatric cancer patients facing critical care complications, herein, we highlight promising areas for future discovery.

Multiple Dynamics in Tumor Microenvironment Under Radiotherapy

The tumor microenvironment (TME) is an evolutionally low-level and embryonically featured tissue comprising heterogenic populations of malignant and stromal cells as well as noncellular components. Under radiotherapy (RT), the major modality for the treatment of malignant diseases [1], TME shows an adaptive response in multiple aspects that affect the efficacy of RT. With the potential clinical benefits, interests in RT combined with immunotherapy (IT) are intensified with a large scale of clinical trials underway for an array of cancer types. A better understanding of the multiple molecular aspects, especially the cross talks of RT-mediated energy reprogramming and immunoregulation in the irradiated TME (ITME), will be necessary for further enhancing the benefit of RT-IT modality. Coming studies should further reveal more mechanistic insights of radiation-induced instant or permanent consequence in tumor and stromal cells. Results from these studies will help to identify critical molecular pathways including cancer stem cell repopulation, metabolic rewiring, and specific communication between radioresistant cancer cells and the infiltrated immune active lymphocytes. In this chapter, we will focus on the following aspects: radiation-repopulated cancer stem cells (CSCs), hypoxia and re-oxygenation, reprogramming metabolism, and radiation-induced immune regulation, in which we summarize the current literature to illustrate an integrated image of the ITME. We hope that the contents in this chapter will be informative for physicians and translational researchers in cancer radiotherapy or immunotherapy.

Abscopal effect in radioimmunotherapy

Abscopal effect is an interesting phenomenon in radiobiology that causes activation of immune system against cancer cells. Traditionally, this phenomenon was known as a suppressor of non-irradiated tumors or metastasis. However, it can be used as a stimulator of the immune system against primary tumor during radiotherapy. Immunotherapy, a novel tumor therapy modality, also triggers immune system against cancer. To date, some immunotherapy types have been developed. However, immune checkpoint blockade is a more common modality and some drugs have been approved by the FDA. Studies have shown that radiotherapy or immunotherapy administered alone have low efficiency for tumor control. However, their combination has a more potent anti-tumor immunity. For this aim, it is important to induce abscopal effect in primary tumors, and also use appropriate drugs to target the mechanisms involved in the exhaustion of cytotoxic CD8+T lymphocytes (CTLs) and natural killer (NK) cells. Among the different radiotherapy techniques, stereotactic body radiation therapy (SBRT) with some few fractionations is the best choice for inducing abscopal effect. On the other hand, programmed cell death 1 (PD-1) is known as one of the best targets for triggering anti-tumor immunity. This combination is known as the best choice among various strategies for radioimmunotherapy. However, there is the need for other strategies to improve the duration of immune system's activity within tumor microenvironment (TME). In this review, we explain the cellular and molecular mechanisms behind abscopal effect by radiotherapy and evaluate the molecular targets which induce potent anti-tumor immunity.

Engineering nanoparticles to reprogram radiotherapy and immunotherapy: recent advances and future challenges

Nanoparticles (NPs) have been increasingly studied for radiosensitization. The principle of NPs radio-enhancement is to use high-atomic number NPs (e.g. gold, hafnium, bismuth and gadolinium) or deliver radiosensitizing substances, such as cisplatin and selenium. Nowadays, cancer immunotherapy is emerged as a promising treatment and immune checkpoint regulation has a potential property to improve clinical outcomes in cancer immunotherapy. Furthermore, NPs have been served as an ideal platform for immunomodulator system delivery. Owing to enhanced permeability and retention (EPR) effect, modified-NPs increase the targeting and retention of antibodies in target cells. The purpose of this review is to highlight the latest progress of nanotechnology in radiotherapy (RT) and immunotherapy, as well as combining these three strategies in cancer treatment. Overall, nanomedicine as an effective strategy for RT can significantly enhance the outcome of immunotherapy response and might be beneficial for clinical transformation.

1,25(OH)2D3 Strengthens the Vasculogenesis of Multipotent Mesenchymal Stromal Cells from Rat Bone Marrow by Regulating the PI3K/AKT Pathway

Background

Multipotent mesenchymal stromal cells (MSCs) have recently been reported to promote vasculogenesis by differentiating into endothelial cells and releasing numerous cytokines and paracrine factors. However, due to low cell activity, their potential for clinical application is not very satisfactory. This study aimed to explore the effects and mechanisms of 1,25-dihydroxyvitamin D (1,25(OH)₂D₃) on the vasculogenesis of MSCs.

Methods

MSCs were isolated from the femurs and tibias of rats and characterized by flow cytometry. After treatment with different concentrations of 1,25(OH)₂D₃ (0 µM, 0.1 µM and 1 µM), the proliferation of MSCs was analyzed by Cell Counting Kit-8 (CCK-8), and the migratory capability was measured by Transwell assays and cell scratch tests. Capillary-like structure formation was observed by using Matrigel. Western blotting was used to detect the expression of FLK-1 and vWF to investigate the differentiation of MSCs into endothelial cells. Western blotting and gelatin zymography were used to detect the expression and activities of VEGF, MMP-2 and MMP-9 secreted by MSCs under the influence of 1,25(OH)₂D_3. Finally, the VDR antagonist pyridoxal-5-phosphate (P5P) and the PI3K/AKT pathway inhibitor LY294002 were utilized to test the phosphorylation levels of key kinases in the PI3K/AKT pathway by Western blotting and the formation of capillary-like structures in Matrigel.

Results

The proliferation and migratory capability of MSCs and the ability of MSCs to form a tube-like structure in Matrigel were enhanced after treatment with 1,25(OH)₂D₃. Moreover, MSCs treated with 1,25(OH)₂D₃ showed high expression of vWF and Flk-1. There was a significant increase in the expression of VEGF, MMP-2 and MMP-9 secreted by MSCs treated with 1,25(OH)₂D_3, as well as in the activity of MMP-2 and MMP-9. The phosphorylation level of AKT increased with time after 1,25(OH)₂D₃ treatment, while LY294002 weakened AKT phosphorylation. In addition, the ability to form capillary-like structures was reduced when the VDR and PI3K/AKT pathways were blocked.

Conclusion

This study confirmed that 1,25(OH)₂D₃ treatment can strengthen the ability of MSCs to promote vasculogenesis in vitro, and the mechanism may be related to the activation of the PI3K/AKT pathway.

Ionizing radiation effects on the tumor microenvironment

The broad use of radiotherapy (RT) in the management of solid human tumors is based on its ability to damage cellular macromolecules, particularly the DNA, effectively inducing growth arrest and cell death locally in irradiated tumor cells. However, bystander effects, such as the transmission of lethal signals between cells via gap junctions or the production of diffusible cytotoxic mediators, can also contribute to the local antineoplastic action of RT. Traditionally, RT has been considered to exert immunosuppressive effects on the host. This idea largely stems from the radiosensitivity of quiescent lymphocytes and on the use of total body irradiation as part of myeloablative conditioning regimens preceding hematopoietic stem cell transplantation. Additionally, the occurrence of the so-called "abscopal effect," where nonirradiated distant lesions display effects of RT response, suggests that RT may also induce tumor immunization. Several RT-induced effects on cancer, immune and stromal cells, contribute to the abscopal effect: (1) induction of "immunogenic cell death", with release of tumor-associated antigens, (2) alterations of cancer cell immunophenotype, and (3) modulation of the tumor microenvironment. Damage and death of cancer cells leads to the surface exposure of immunogenic molecules as well as the release of damage associated molecular patterns such as adenosine triphosphate or High-Mobility-Group-Protein B1, and potentially tumor antigens that activate the innate and adaptive immune systems. Moreover, nuclear release and cytoplasmic sensing of altered nucleic acids via cyclic GMP-AMP Synthase/Stimulator of Interferon Genes is connected to the secretion of cytokines that support innate and adaptive antitumor immunity. As a result of the above, irradiated tumor cells may potentially act as an "in situ vaccine."

The Effects of Astragalus Polysaccharide on Bone Marrow-Derived Mesenchymal Stem Cell Proliferation and Morphology Induced by A549 Lung Cancer Cells

BACKGROUND The tumor microenvironment in lung cancer plays an important role in tumor progression and metastasis. Bone marrow-derived mesenchymal stem cells (MSCs) co-cultured with A549 lung cancer cells show changes in morphology, increase cell proliferation, and cell migration. This study aimed to investigate the effects of Astragalus polysaccharide (APS), a traditional Chinese herbal medicine, on the changes induced in bone marrow-derived MSCs by A549 lung cancer cells in vitro. MATERIAL AND METHODS Bone marrow-derived MSCs were co-cultured with A549 cells (Co-BMSCs). Co-cultured bone marrow-derived MSCs and A549 cells treated with 50 μg/ml of APS (Co-BMSCs + APS) were compared with untreated Co-BMSCs. Cell proliferation was measured using the cell counting kit-8 (CCK-8) assay. Flow cytometry evaluated the cell cycle. Microarray assays for mRNA expression and Western blot for protein expression were used. RESULTS Compared with untreated Co-BMSCs, APS treatment of Co-BMSCs improved cell morphology, reduced cell proliferation, and inhibited cell cycle arrest. The mitogen-activated protein kinase (MAPK)/nuclear factor-kappa B (NF-kappaB) pathway, TP53, caspase-3, acetylated H4K5, acetylated H4K8, and acetylated H3K9 were involved in the regulatory process. CONCLUSIONS APS treatment reduced cell proliferation and morphological changes in bone marrow-derived MSCs that were co-cultured with A549 lung cancer cells in vitro.

Targeting pericytes for neurovascular regeneration

Pericytes, as a key cellular part of the blood-brain barrier, play an important role in the maintenance of brain neurovascular unit. These cells participate in brain homeostasis by regulating vascular development and integrity mainly through secreting various factors. Pericytes per se show different restorative properties after blood-brain barrier injury. Upon the occurrence of brain acute and chronic diseases, pericytes provoke immune cells to regulate neuro-inflammatory conditions. Loss of pericytes in distinct neurologic disorders intensifies blood-brain barrier permeability and leads to vascular dementia. The therapeutic potential of pericytes is originated from the unique morphological shape, location, and their ability in providing vast paracrine and juxtacrine interactions. A subset of pericytes possesses multipotentiality and exhibit trans-differentiation capacity in the context of damaged tissue. This review article aimed to highlight the critical role of pericytes in restoration of the blood-brain barrier after injury by focusing on the dynamics of pericytes and cross-talk with other cell types.

Human bone marrow-derived mesenchymal stem cells promote the growth and drug-resistance of diffuse large B-cell lymphoma by secreting IL-6 and elevating IL-17A levels

Background

The drug-resistance and relapse of diffuse large B-cell lymphoma (DLBCL), which are related to mesenchymal stem cells (MSCs), have become increasingly common. However, the underlying mechanisms remain elusive.

Methods

CCK 8 assay, colony formation assay, and xenograft mouse model were used to investigate the effects of hBMSCs on DLBCL growth. Immunohistochemistry, qRT-PCR, and ELISA were used to study the expressions of IL-6 and IL-17A. Flow cytometry was used to analyze Th17 cells and Treg cells expressions. Western blot analysis, microarray analysis, and bioinformatics analysis were used to analyze the pathways of IL-6 or IL-17A mediated DLBCL growth.

Results

HBMSCs promoted DLBCL growth by secreting IL-6 in vitro and in vivo and simultaneously upregulating IL-17A in vitro. IL-6 and IL-17A synergistically promoted the growth and drug-resistance of DLBCL cells by protecting them from spontaneous or drug-induced apoptosis in vitro. IL-6 or IL-17A activated the JAK2/STAT3 pathway or upregulated cyclin D2 via activation of PI3K/Akt signaling in vitro, respectively.

Conclusions

The present results indicated that hBMSCs might have a “dual effect” on promoting DLBCL progression and drug-resistance by secreting IL-6 and upregulating IL-17A. IL-6, IL-17A, p-STAT3, p-Akt or cyclin D2 may be potential molecular targets for overcoming drug-resistance in patients with relapsed or refractory DLBCL.

Mesenchymal stem cells in suppression or progression of hematologic malignancy: current status and challenges

Mesenchymal stem cells (MSCs) are known for being multi-potent. However, they also possess anticancer properties, which has prompted efforts to adapt MSCs for anticancer therapies. However, MSCs have also been widely implicated in pathways that contribute to tumor growth. Numerous studies have been conducted to adapt MSCs for further clinical use; however, the results have been inconclusive, possibly due to the heterogeneity of MSC populations. Moreover, the conflicting roles of MSCs in tumor inhibition and tumor growth impede their adaptation for anticancer therapies. Antitumorigenic and protumorigenic properties of MSCs in hematologic malignancies are not as well established as they are for solid malignancies, and data comparing them are still limited. Herein the effect of MSCs on hematologic malignancies, such as leukemia and lymphoma, their mechanisms, sources of MSCs, and their effects on different types of cancer, have been discussed. This review describes how MSCs preserve both antitumorigenic and protumorigenic effects, as they tend to not only inhibit tumor growth by suppressing tumor cell proliferation but also promote tumor growth by suppressing tumor cell apoptosis. Thus clinical studies trying to adapt MSCs for anticancer therapies should consider that MSCs could actually promote hematologic cancer progression. It is necessary to take extreme care while developing MSC-based cell therapies in order to boost anticancer properties while eliminating tumor-favoring effects. This review emphasizes that research on the therapeutic applications of MSCs must consider that they exert both antitumorigenic and protumorigenic effects on hematologic malignancies.

Mesenchymal Stem Cells: Miraculous Healers or Dormant Killers?

Mesenchymal Stem Cells (MSCs) are a heterogeneous population of fibroblast-like cells which maintain self-renewability and pluripotency to differentiate into mesodermal cell lineages. The use of MSCs in clinical settings began with high enthusiasm and the number of MSC-based clinical trials has been rising ever since. However; the very unique characteristics of MSCs that made them suitable to for therapeutic use, might give rise to unwanted outcomes, including tumor formation and progression. In this paper, we present a model of carcinogenesis initiated by MSCs, which chains together the tissue organization field theory, the stem cell theory, and the inflammation-cancer chain. We believe that some tissue resident stem cells could be leaked cells from bone marrow MSC pool to various injured tissue, which consequently transform and integrate in the host tissue. If the injury persists or chronic inflammation develops, as a consequence of recurring exposure to growth factors, cytokines, etc. the newly formed tissue from MSCs, which still has conserved their mesenchymal and stemness features, go through rapid population expansion, and nullify their tumor suppressor genes, and hence give rise to neoplastic cell (carcinomas, sarcomas, and carcino-sarcomas). Considering the probability of this hypothesis being true, the clinical and therapeutic use of MSCs should be with caution, and the recipients' long term follow-up seems to be insightful.

Potential Role of CXCR4 Targeting in the Context of Radiotherapy and Immunotherapy of Cancer

Cancer immunotherapy has been established as standard of care in different tumor entities. After the first reports on synergistic effects with radiotherapy and the induction of abscopal effects-tumor shrinkage outside the irradiated volume attributed to immunological effects of radiotherapy-several treatment combinations have been evaluated. Different immunotherapy strategies (e.g., immune checkpoint inhibition, vaccination, cytokine based therapies) have been combined with local tumor irradiation in preclinical models. Clinical trials are ongoing in different cancer entities with a broad range of immunotherapeutics and radiation schedules. SDF-1 (CXCL12)/CXCR4 signaling has been described to play a major role in tumor biology, especially in hypoxia adaptation, metastasis and migration. Local tumor irradiation is a known inducer of SDF-1 expression and release. CXCR4 also plays a major role in immunological processes. CXCR4 antagonists have been approved for the use of hematopoietic stem cell mobilization from the bone marrow. In addition, several groups reported an influence of the SDF-1/CXCR4 axis on intratumoral immune cell subsets and anti-tumor immune response. The aim of this review is to merge the knowledge on the role of SDF-1/CXCR4 in tumor biology, radiotherapy and immunotherapy of cancer and in combinatorial approaches.

Targeting PDGF-mediated recruitment of pericytes blocks vascular mimicry and tumor growth

Aggressive tumor cells can adopt an endothelial cell-like phenotype and contribute to the formation of a tumor vasculature, independent of tumor angiogenesis. This adoptive mechanism is referred to as vascular mimicry and it is associated with poor survival in cancer patients. To what extent tumor cells capable of vascular mimicry phenocopy the angiogenic cascade is still poorly explored. Here, we identify pericytes as important players in vascular mimicry. We found that pericytes are recruited by vascular mimicry-positive tumor cells in order to facilitate sprouting and to provide structural support of the vascular-like networks. The pericyte recruitment is mediated through platelet-derived growth factor (PDGF)-B. Consequently, preventing PDGF-B signaling by blocking the PDGF receptors with either the small tyrosine kinase inhibitor imatinib or blocking antibodies inhibits vascular mimicry and tumor growth. Collectively, the current study identifies an important role for pericytes in the formation of vascular-like structures by tumor cells. Moreover, the mechanism that controls the pericyte recruitment provides therapeutic opportunities for patients with aggressive vascular mimicry-positive cancer types. © 2018 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of Pathological Society of Great Britain and Ireland.

Effect of Stromal Cells in Tumor Microenvironment on Metastasis Initiation

The cellular environment where tumor cells reside is called the tumor microenvironment (TME), which consists of borders, blood vessels, lymph vessels, extracellular matrix (ECM), stromal cells, immune/inflammatory cells, secreted proteins, RNAs and small organelles. By dynamically interacting with tumor cells, stromal cells participate in all stages of tumor initiation, progression, metastasis, recurrence and drug response, and consequently, affect the fate of patients. During the processes of tumor evolution and metastasis initiation, stromal cells in TME also experience some changes and play roles in both the suppression and promotion of metastasis, while the overall function of stromal cells is beneficial for cancer cell survival and movement. In this review, we examine the effects of stromal cells in TME on metastasis initiation, including angiogenesis, epithelial-mesenchymal transition (EMT) and invasion. We also highlight functions of proteins, RNAs and small organelles secreted by stromal cells in their influences on multiple stages of tumor metastasis.

Detection of endogenously circulating mesenchymal stem cells in human cancer patients

Mesenchymal stem cells (MSCs) can play a vital role in tumor progression and anticancer therapy response, as demonstrated by various in vitro and in vivo model systems. Their ability to home to developing tumors and modulate the tumor microenvironment, by suppressing T-cell responses and contributing to the tumor stroma, is suggested to have a significant impact on disease progression, metastasis formation, and therapy response. Most evidence, however, is derived from artificial models using exogenously administered MSCs. The contribution of endogenous MSCs to tumor progression is currently unclear. Furthermore, few studies have been conducted in humans. A prospective biomarker study was therefore undertaken in 40 human cancer patients and 10 healthy controls of similar age, aimed at (i) exploring and quantifying circulating MSC levels in healthy volunteers and patients with advanced malignancies, (ii) determining the variability of MSC levels between healthy volunteers and cancer patients with different histologic tumor types, and (iii) exploring biomarkers associated with MSC levels. Significantly increased levels of circulating MSC-like cells were observed in cancer patients when compared to healthy individuals (1.72 fold difference, 95% CI 1.03-2.81%, p = 0.03). In addition, prior systemic therapy was associated with a significant increase in MSC-like cells (1.73 fold difference, 95% CI 1.02-2.95, p = 0.04). These results indicate that the amount of endogenously circulating MSCs in humans is increased in response to cancer, and that systemic anticancer treatment can influence MSC levels. Further research is needed to determine whether MSCs have a predictive value.

Radiation-Induced Transformation of Immunoregulatory Networks in the Tumor Stroma

The implementation of novel cancer immunotherapies in the form of immune checkpoint blockers represents a major advancement in the treatment of cancer, and has renewed enthusiasm for identifying new ways to induce antitumor immune responses in patients. Despite the proven efficacy of neutralizing antibodies that target immune checkpoints in some refractory cancers, many patients do not experience therapeutic benefit, possibly owing to a lack of antitumor immune recognition, or to the presence of dominant immunosuppressive mechanisms in the tumor microenvironment (TME). Recent developments in this field have revealed that local radiotherapy (RT) can transform tumors into in situ vaccines, and may help to overcome some of the barriers to tumor-specific immune rejection. RT has the potential to ignite tumor immune recognition by generating immunogenic signals and releasing neoantigens, but the multiple immunosuppressive forces in the TME continue to represent important barriers to successful tumor rejection. In this article, we review the radiation-induced changes in the stromal compartments of tumors that could have an impact on tumor immune attack. Since different RT regimens are known to mediate strikingly different effects on the multifarious elements of the tumor stroma, special emphasis is given to different RT schedules, and the time after treatment at which the effects are measured. A better understanding of TME remodeling following specific RT regimens and the window of opportunity offered by RT will enable optimization of the design of novel treatment combinations.

Mutual concessions and compromises between stromal cells and cancer cells: driving tumor development and drug resistance

BACKGROUND

Various cancers have been found to be associated with heterogeneous and adaptive tumor microenvironments (TMEs) and to be driven by the local TMEs in which they thrive. Cancer heterogeneity plays an important role in tumor cell survival, progression and drug resistance. The diverse cellular components of the TME may include cancer-associated fibroblasts, adipocytes, pericytes, mesenchymal stem cells, endothelial cells, lymphocytes and other immune cells. These components may support tumor development through the secretion of growth factors, evasion from immune checkpoints, metabolic adaptations, modulations of the extracellular matrix, activation of oncogenes and the acquisition of drug resistance. Here, we will address recent advances in our understanding of the molecular mechanisms underlying stromal-tumor cell interactions, with special emphasis on basic and pre-clinical information that may facilitate the design of novel personalized cancer therapies.

CONCLUSIONS

This review presents a holistic view on the translational potential of the interplay between stromal cells and cancer cells. This interplay is currently being employed for the development of promising preclinical and clinical biomarkers, and the design of small molecule inhibitors, antibodies and small RNAs for (combinatorial) cancer treatment options. In addition, nano-carriers, tissue scaffolds and 3-D based matrices are being developed to precisely and safely deliver these compounds.

Tissue Specific Origin, Development, and Pathological Perspectives of Pericytes

Pericytes are mural cells surrounding blood vessels, adjacent to endothelial cells. Pericytes play critical roles in maturation and maintenance of vascular branching morphogenesis. In the central nervous system (CNS), pericytes are necessary for the formation and regulation of the blood-brain barrier (BBB) and pericyte deficiency accompanies CNS diseases including multiple sclerosis, diabetic retinopathy, neonatal intraventricular hemorrhage, and neurodegenerative disorders. Despite the importance of pericytes, their developmental origins and phenotypic diversity remain incompletely understood. Pericytes express multiple markers and the origin of pericytes differs by tissue, which may cause difficulty for the identification and understanding of the ontogeny of pericytes. Also, pericytes have the potential to give rise to different tissues in vitro but this is not clear in vivo. These studies indicate that pericytes are heterogeneous in a tissue- and context- dependent manner. This short review focuses on recent studies about identification of pericytes, heterogeneous origin of pericytes during development and in adults, and the differentiation capacity of pericytes, and pericytes in pathological settings.

The importance of the vascular endothelial barrier in the immune-inflammatory response induced by radiotherapy

Altered by ionising radiation, the vascular network is considered as a prime target to limit normal tissue damage and improve tumour control in radiotherapy (RT). Irradiation damages and/or activates endothelial cells, which then participate in the recruitment of circulating cells, especially by overexpressing cell adhesion molecules, but also by other as yet unknown mechanisms. Radiation-induced lesions are associated with infiltration of immune-inflammatory cells from the blood and/or the lymph circulation. Damaged cells from the tissues and immune-inflammatory resident cells release factors that attract cells from the circulation, leading to the restoration of tissue balance by fighting against infection, elimination of damaged cells and healing of the injured area. In normal tissues that surround the tumours, the development of an immune-inflammatory reaction in response to radiation-induced tissue injury can turn out to be chronic and deleterious for the organ concerned, potentially leading to fibrosis and/or necrosis of the irradiated area. Similarly, tumours can elicit an immune-inflammation reaction, which can be initialised and amplified by cancer therapy such as radiotherapy, although immune checkpoints often allow many cancers to be protected by inhibiting the T-cell signal. Herein, we have explored the involvement of vascular endothelium in the fate of healthy tissues and tumours undergoing radiotherapy. This review also covers current investigations that take advantage of the radiation-induced response of the vasculature to spare healthy tissue and/or target tumours better.

Skin CanceR Brachytherapy vs External beam radiation therapy (SCRiBE) meta-analysis

BACKGROUND AND PURPOSE

To compare cosmesis and local recurrence (LR) of definitive external beam radiation therapy (EBRT) vs brachytherapy (BT) for indolent basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) of the skin.

MATERIALS AND METHODS

Studies including patients with T1-2 N0 SCCs/BCCs treated with definitive EBRT/BT and ≥10 months follow-up were analyzed. The primary endpoint was post-treatment cosmesis, categorized as "good," "fair," or "poor." The secondary endpoint was LR. Mixed effects regression models were used to estimate weighted linear relationships between biologically equivalent doses with α/β = 3 (BED3) and cosmetic outcomes.

RESULTS

A total of 9965 patients received EBRT and 553 received BT across 24 studies. Mean age was 73 years, median follow-up was 36 months, and median dose was 45 Gy/10 fractions at 4.4 Gy/fraction. At BED3 of 100 Gy, "good" cosmesis was more frequently observed in patients receiving BT, 95% (95% CI: 88-100%) vs 79% (95% CI: 60-82%), p < 0.05. Similar results were found for "good" cosmesis at BED3 >100 Gy. No difference in "poor" cosmesis was noted at any BED3. LR was <7% for both at one year.

CONCLUSION

BT has favorable cosmesis over EBRT for skin SCCs/BCCs at common fractionation regimens. Prospective studies comparing EBRT vs BT are warranted.

Ablative Hypofractionated Radiation Therapy Enhances Non-Small Cell Lung Cancer Cell Killing via Preferential Stimulation of Necroptosis In Vitro and In Vivo

PURPOSE

To investigate how necroptosis (ie, programmed necrosis) is involved in killing of non-small cell lung cancer (NSCLC) after ablative hypofractionated radiation therapy (HFRT).

METHODS AND MATERIALS

Deoxyribonucleic acid damage, DNA repair, and the death form of NSCLC cells were assessed after radiation therapy. The overexpression and silencing of receptor-interacting protein kinases 3 (RIP3, a key protein involved activation of necroptosis)-stable NSCLC cell lines were successfully constructed. The form of cell death, the number and area of colonies, and the regulatory proteins of necroptosis were characterized after radiation therapy in vitro. Finally, NSCLC xenografts and patient specimens were used to examine involvement of necroptosis after ablative HFRT in vivo.

RESULTS

Radiation therapy induced expected DNA damage and repair of NSCLC cell lines, but ablative HFRT at ≥10 Gy per fraction preferentially stimulated necroptosis in NSCLC cells and xenografts with high RIP3 expression, as characterized by induction and activation of RIP3 and mixed-lineage kinase domain-like protein and release of immune-activating chemokine high-mobility group box 1. In contrast, RNA interference of RIP3 attenuated ablative HFRT-induced necroptosis and activation of its regulatory proteins. Among central early-stage NSCLC patients receiving stereotactic body radiation therapy, high expression of RIP3 was associated with improved local control and progression-free survival (all P < .05).

CONCLUSIONS

Ablative HFRT at ≥10 Gy per fraction enhances killing of NSCLC with high RIP3 expression via preferential stimulation of necroptosis. RIP3 may serve as a useful biomarker to predict favorable response to stereotactic body radiation therapy.

Mesenchymal stem cells promote cell invasion and migration and autophagy-induced epithelial-mesenchymal transition in A549 lung adenocarcinoma cells

Mesenchymal stem cells (MSCs) are recruited into the tumour microenvironment and promote tumour growth and metastasis. Tumour microenvironment-induced autophagy is considered to suppress primary tumour formation by impairing migration and invasion. Whether these recruited MSCs regulate tumour autophagy and whether autophagy affects tumour growth are controversial. Our data showed that MSCs promote autophagy activation, reactive oxygen species production, and epithelial-mesenchymal transition (EMT) as well as increased migration and invasion in A549 cells. Decreased expression of E-cadherin and increased expression of vimentin and Snail were observed in A549 cells cocultured with MSCs. Conversely, MSC coculture-mediated autophagy positively promoted tumour EMT. Autophagy inhibition suppressed MSC coculture-mediated EMT and reduced A549 cell migration and invasion slightly. Furthermore, the migratory and invasive abilities of A549 cells were additional increased when autophagy was further enhanced by rapamycin treatment. Taken together, this work suggests that microenvironments containing MSCs can promote autophagy activation for enhancing EMT; MSCs also increase the migratory and invasive abilities of A549 lung adenocarcinoma cells. Mesenchymal stem cell-containing microenvironments and MSC-induced autophagy signalling may be potential targets for blocking lung cancer cell migration and invasion.

Systemic Inflammation Biomarkers Predict Survival in Patients of Early Stage Non-Small Cell Lung Cancer Treated With Stereotactic Ablative Radiotherapy - A Single Center Experience

Background: Increasing evidence indicates a relationship between systemic inflammation and survival following treatment in various tumors. However, the correlation of systematic inflammation with survival after stereotactic ablative radiotherapy (SABR) in early stage non-small cell lung cancer (NSCLC) has not been well established.

Patients and methods: We retrospectively analyzed patients with newly diagnosed early stage NSCLC treated with SABR in a single institution from 2011 to 2015. The neutrophil-lymphocyte ratio (NLR), platelet-lymphocyte ratio (PLR), and lymphocyte- monocyte ratio (LMR) were calculated as systemic inflammation biomarkers. Overall survival (OS) was the first end-point. Receiver operating characteristic (ROC) was used to determine cut-off points for OS. Univariate and multivariate Cox proportional hazards regression were used to investigate the potential factors associated with OS.

Results: In the 63 patients who were eligible for analysis. The median follow up after SBRT was 29.5 months (range 8-67 months) while the 3-year OS was 74.2%. Based on ROC analysis, optimal cut-off values of NLR, PLR, and LMR were 2.06, 199.55 and 4.0, respectively. Significant survival benefit was found in the NLR ≤2.06 group (p=0.028), PLR≤199.55 group (p=0.001), and LMR˃4.0 group (p=0.046). Univariate analysis indicated that low NLR (p=0.011), low PLR (p=0.003), and high LMR (p=0.014) were correlated with improved survival. Multivariate analysis indicated that high PLR (p=0.033) and low LMR (p=0.046) were independent prognostic factors for poor survival.

Conclusions: In patients of early stage NSCLC who received SABR, pretreatment NLR, PLR, and LMR could be considered useful prognostic indicators of OS. These metrics may provide reliable and convenient predictors to identify patients who would benefit from SABR.

Apatinib alone or combined with radiotherapy in metastatic prostate cancer: Results from a pilot, multicenter study

Background

To study safety and efficacy of apatinib in combination of radiotherapy in patients with symptomatic bony disease prostate cancer(SBPC), based on the potential synergistic antitumor activity between apatinib and Radiation Therapy (RT).

Patients and methods

In phase I dose escalation part, 18 patients received apatinib dose at 250 mg every other day, 250 mg daily and 500 mg daily. In phase II part, the 250 mg daily cohorts were expanded to 20 patients in combination of RT (6 Gy/fraction, 5 fraction in total), one patient lost followed up and excluded the study, comparing with RT alone cohort with 10 patients, ratio of RT to RT + apatinib was 1 to 2. Evaluations included adverse events (AEs), prostate specific antigen (PSA) changes, radiographic evaluation and pain relief.

Results

In phase I study, common apatinib-related AEs (arAEs) were fatigue, anorexia, hand foot syndrome, proteinuria, and hypertension (HTN). Grade 3arAEs included HTN, proteinuria, liver dysfunction. In phase II study, combination apatinib with RT cohorts, AEs events increased comparing with either apatinib alone or RT alone; at the same time, combination cohorts showed PSA declines of ≥50% in 12 patients, and stable disease in 6 patients. Combination cohorts had pain control significantly improved in both level and duration comparing with RT alone.

Conclusions

In SBPC patients, apatinib at less than 500 mg daily dose as mono-therapy had tolerable toxicity. Apatinib at dose of 250 mg daily in combining with RT synergized pain control, the overall AEs were manageable. Further studies are needed in large sample size future trials.

Effects of interruptions of external beam radiation therapy on outcomes in patients with prostate cancer

INTRODUCTION

To evaluate if interruptions of external beam radiation therapy impact outcomes in men with localized prostate cancer (PCa).

METHODS

We included men with localized PCa treated with three-dimensional conformal radiotherapy (3D-CRT) or intensity-modulated radiation therapy (IMRT) of escalated dose (≥74 Gy in 1.8 or 2 Gy fractions) between 1992 and 2013 at an NCI-designated cancer centre. Men receiving androgen deprivation therapy were excluded. The non-treatment day ratio (NTDR) was defined as the number of non-treatment days divided by the total elapsed days of therapy. NTDR was analysed for each National Comprehensive Cancer Network (NCCN) risk group.

RESULTS

There were 1728 men included (839 low-risk, 776 intermediate-risk and 113 high-risk), with a median follow up of 53.5 months (range 12-185.8). The median NTDR was 31% (range 23-71%), translating to approximately 2 breaks (each break represents a missed treatment that will be made up) for 8 weeks of RT with 5 treatments per week. The 75 percentile of NTDR was 33%, translating to approximately 4 breaks, which was used as the cutoff for analysis. There were no significant differences in freedom from biochemical failure, freedom from distant metastasis, cancer specific survival, or overall survival for men with NTDR ≥33% compared to NTDR<33% for each risk group. Multivariable analyses including NTDR, age, race, Gleason score, T stage, and PSA were performed using the proportional hazards regression procedure. NTDR≥33% was not significantly associated with increased hazard ratio for outcomes in each risk group compared to NTDR<33%.

CONCLUSION

Unintentional treatment breaks during dose escalated external beam radiation therapy for PCa did not cause a significant difference in outcomes, although duration of follow up limits the strength of this conclusion.

Hypofractionated radiation therapy for basal and squamous cell skin cancer: A meta-analysis

PURPOSE

To characterize the cosmetic outcomes and local recurrence (LR) rates of various hypofractionated radiation therapy (RT) regimens for skin basal and squamous cell cancers (BCCs/SCCs).

METHODS

A PICOS/PRISMA/MOOSE selection protocol was performed to identify 344 articles published between 1985-2016 evaluating patients with T1-2 N0 SCCs/BCCs treated with definitive RT. Biologically equivalent doses with α/β=3 (BED3s) were calculated. The primary endpoint was post-treatment cosmesis. Mixed effects regression models were used to estimate weighted linear relationships between BED3 and cosmetic outcomes.

RESULTS

A total of 21 studies were identified detailing the treatment of 9729 skin BCC/SCC patients, across seven countries, with external beam RT (n=9255) or brachytherapy (n=474). Median follow-up was 36months (range: 12-77). Median dose was 45Gy/11 fractions (interquartile range: 37.5Gy/6-55Gy/18) at 4Gy/fraction (interquartile range: 2.5-6Gy); most hypofractionated 18.75Gy/1. There was a trend to decreased "good" cosmesis with higher total dose: -3.4% "good" cosmesis/10Gy BED3, p=0.01. Similarly, there was a trend to increased "fair" cosmesis with higher dose: +3.8% "fair" cosmesis/10Gy BED3,p=0.006. At a BED3 of 100Gy, the expected rate of "good" cosmesis is 79% (95% confidence interval: 70%, 88%). Hypofractionated schedules produced similar cosmesis to conventionally fractionated schedules, at the same BED3. Fewer than 8% of patients experienced "poor" cosmesis, independent of dose or fractionation regimen.

CONCLUSION

Hypofractionated RT has favorable cosmesis for patients with skin BCCs/SCCs. We recommend clinicians consider these commonly-used regimens, which all have BED3 of ∼100Gy: 50Gy/15 fractions, 36.75Gy/7 fractions, or 35Gy/5 fractions, as they result in "good" cosmesis in 80% of patients.

The evolution of brachytherapy for prostate cancer

Brachytherapy (BT), using low-dose-rate (LDR) permanent seed implantation or high-dose-rate (HDR) temporary source implantation, is an acceptable treatment option for select patients with prostate cancer of any risk group. The benefits of HDR-BT over LDR-BT include the ability to use the same source for other cancers, lower operator dependence, and - typically - fewer acute irritative symptoms. By contrast, the benefits of LDR-BT include more favourable scheduling logistics, lower initial capital equipment costs, no need for a shielded room, completion in a single implant, and more robust data from clinical trials. Prospective reports comparing HDR-BT and LDR-BT to each other or to other treatment options (such as external beam radiotherapy (EBRT) or surgery) suggest similar outcomes. The 5-year freedom from biochemical failure rates for patients with low-risk, intermediate-risk, and high-risk disease are >85%, 69-97%, and 63-80%, respectively. Brachytherapy with EBRT (versus brachytherapy alone) is an appropriate approach in select patients with intermediate-risk and high-risk disease. The 10-year rates of overall survival, distant metastasis, and cancer-specific mortality are >85%, <10%, and <5%, respectively. Grade 3-4 toxicities associated with HDR-BT and LDR-BT are rare, at <4% in most series, and quality of life is improved in patients who receive brachytherapy compared with those who undergo surgery.

Post-surgery fluids promote transition of cancer stem cell-to-endothelial and AKT/mTOR activity, contributing to relapse of giant cell tumors of bone

Giant cell tumors of bone (GCTB) are rare sarcomas with a high rate of unpredictable local relapse. Studies suggest that surgical methods affect recurrence, supporting the idea that local disease develops from re-growth of residual cancer cells. To identify early prognostic markers of individual risk of recurrence, we evaluated the effect of post-surgery fluids from a cohort of GCTB patients on growth of primary and established sarcoma cell lines, and mice xenograph. Post-surgery fluids increased cell growth and enhanced expression of CD44⁺⁺, the principal receptor for the extracellular matrix component hyaluronan and the mesenchymal stem marker CD117⁺. Cancer cells became highly invasive and tumorigenic, acquiring stemness properties, and activated AKT/mTOR pathway. Prolonged stimulation with post-surgery fluids down-regulated the mesenchymal gene TWIST1 and Vimentin protein, and transdifferentiated cells into tubule-like structures positive to the endothelial markers VE-Cadherin and CD31⁺. In mice, post-surgery fluids gave rise to larger and more vascularized tumors than control, while in patients AKT/mTOR pathway activation was associated with recurrence by logistic regression (Kaplan-Meier; P<0.001). These findings indicate that post-surgery fluids are an adjuvant in mechanisms of tumor regrowth, increasing stem cell growth and AKT/mTOR activity.

Cavin-2 Functions as a Suppressive Regulator in TNF-induced Mesenchymal Stromal Cell Inflammation and Angiogenic Phenotypes

Tumour necrosis factor (TNF)-α activation of mesenchymal stromal cells (MSC) enhances their tumour-suppressive properties and tumour-homing ability. The molecular actors involved are unknown. We found that TNF induced MSC migration and tubulogenesis which correlated with a dose-dependent increase in Cavin-1 and Cavin-3 transcript levels. TNF triggered cyclooxygenase (COX)-2 expression, whereas specific siRNA-mediated gene silencing of Cavin-2 resulted in an amplified COX-2 expression, tubulogenesis, and migratory response partially due to a rapid and sustained increase in NF-κB phosphorylation status. Our results highlight a suppressive role for the caveolar component Cavin-2 in the angiogenic and inflammatory regulation of TNF-activated MSC.