Far-infrared irradiation increases the uptake of LDL cholesterol by downregulating PCSK9 through the activation of TRPV4 calcium channels in HepG2 cells.

This study investigated the effects of far-infrared (FIR) irradiation on low-density lipoprotein cholesterol (LDL-C) uptake by human hepatocellular carcinoma G2 (HepG2) cells via the regulation of proprotein convertase subtilisin/kexin type 9 (PCSK9). FIR irradiation for 30 min significantly decreased PCSK9 expression (p < 0.01) in HepG2 cells. FIR irradiation substantially increased the low-density lipoprotein receptor (p < 0.0001) and LDL-C uptake (p < 0.01). Activation of transient receptor potential vanilloid (TRPV) channels mimicked the effects of FIR irradiation, significantly decreasing the protein expression of PCSK9 (p < 0.05). Conversely, inhibition of TRP channels using ruthenium red reversed the reduction in PCSK9 protein expression following FIR irradiation (p < 0.01). The specific activation of TRPV4 using 4α-PDD mimicked the effect of FIR irradiation (p < 0.01), whereas PCSK9 reduction by FIR irradiation was significantly reversed by the inhibition of TRPV4 using RN1734 (p < 0.05). These findings implied that FIR irradiation emitted from a ceramic lamp specifically increased TRPV4 activity. These findings provide insights into a novel therapeutic approach using FIR irradiation for LDL-C regulation and its implications for cardiovascular health.

Response of genes related to iron and porphyrin transport in Porphyromonas gingivalis to blue light.

BACKGROUND: Antimicrobial blue light (aBL) kills a variety of bacteria, including Porphyromonas gingivalis. However, little is known about the transcriptomic response of P. gingivalis to aBL therapy. This study was designed to evaluate the selective cytotoxicity of aBL against P. gingivalis over human cells and to further investigate the genetic response of P. gingivalis to aBL at the transcriptome level. METHODS: Colony forming unit (CFU) testing, confocal laser scanning microscopy (CLSM), and scanning electron microscopy (SEM) were used to investigate the antimicrobial effectiveness of blue light against P. gingivalis. The temperatures of the irradiated targets were measured to prevent overheating. Multiple fluorescent probes were used to quantify reactive oxygen species (ROS) generation after blue-light irradiation. RNA sequencing (RNA-seq) was used to investigate the changes in global gene expression. Following the screening of target genes, real-time quantitative polymerase chain reaction (RT-qPCR) was performed to confirm the regulation of gene expression. RESULTS: A 405 nm aBL at 100 mW/cm2 significantly killed P. gingivalis within 5 min while sparing human gingival fibroblasts (HGFs). No obvious temperature changes were detected in the irradiated surface under our experimental conditions. RNA-seq showed that the transcription of multiple genes was regulated, and RT-qPCR revealed that the expression levels of the genes RgpA and RgpB, which may promote heme uptake, as well as the genes Ftn and FetB, which are related to iron homeostasis, were significantly upregulated. The expression levels of the FeoB-2 and HmuR genes, which are related to hydroxyl radical scavenging, were significantly downregulated. CONCLUSIONS: aBL strengthens the heme uptake and iron export gene pathways while reducing the ROS scavenging pathways in P. gingivalis, thus improving the accumulation of endogenous photosensitizers and enhancing oxidative damage to P. gingivalis.

Ionizing radiation downregulates estradiol synthesis via endoplasmic reticulum stress and inhibits the proliferation of estrogen receptor-positive breast cancer cells.

Breast cancer is a major threat to women's health and estrogen receptor-positive (ER+) breast cancer exhibits the highest incidence among these cancers. As the primary estrogen, estradiol strongly promotes cellular proliferation and radiotherapy, as a standard treatment, exerts an excellent therapeutic effect on ER+ breast cancer. Therefore, we herein wished to explore the mechanism(s) underlying the inhibitory effects of radiation on the proliferation of ER+ breast cancer cells. We used the ER+ breast cancer cell lines MCF7 and T47D, and their complementary tamoxifen-resistant cell lines in our study. The aforementioned cells were irradiated at different doses of X-rays with or without exogenous estradiol. CCK8 and clone-formation assays were used to detect cellular proliferation, enzyme-linked immunosorbent assay (ELISA) to determine estradiol secretion, western immunoblotting analysis and quantitative real-time PCR to evaluate the expression of proteins, and immunofluorescence to track endoplasmic reticulum stress-related processes. Finally, BALB/C tumor-bearing nude mice were irradiated with X-rays to explore the protein expression in tumors using immunohistochemistry. We found that ionizing radiation significantly reduced the phosphorylation of estrogen receptors and the secretion of estradiol by ER+ breast cancer cells. CYP19A (aromatase) is an enzyme located in the endoplasmic reticulum, which plays a critical role in estradiol synthesis (aromatization), and we further demonstrated that ionizing radiation could induce endoplasmic reticulum stress with or without exogenous estradiol supplementation, and that it downregulated the expression of CYP19A through ER-phagy. In addition, ionizing radiation also promoted lysosomal degradation of CYP19A, reduced estradiol synthesis, and inhibited the proliferation of tamoxifen-resistant ER+ breast cancer cells. We concluded that ionizing radiation downregulated the expression of CYP19A and reduced estradiol synthesis by inducing endoplasmic reticulum stress in ER+ breast cancer cells, thereby ultimately inhibiting cellular proliferation.

Photobiomodulation inhibits inflammation in the temporomandibular joint of rats.

Photobiomodulation (PBM) has been applied as a non-invasive technique for treating temporomandibular joint symptoms, especially on painful condition's relief, however the anti-inflammatory mechanism underlying the effect of PBM remains uncertain. This study aims to evaluate the mechanisms of action of PBM (808 nm) in a carrageenan-induced inflammation on temporomandibular joint (TMJ) of rats. In this study male Wistar rats were pre-treated with irradiation of a low-power diode laser for 15 s on TMJ (infra-red 808 nm, 100 mW, 50 J/cm2 and 1.5 J) 15 min prior an injection in the temporomandibular joint of carrageenan (100 µg/TMJ). 1 h after the TMJ treatments, the rats were terminally anesthetized for joint cavity wash and periarticular tissues collect. Samples analysis demonstrated that PBM inhibit leukocytes chemotaxis in the TMJ and significantly reduces amounts of TNF-α, IL-1ß and CINC-1. In addition, Western blotting analysis demonstrated that PBM significantly decreased the protein levels of P2X3 and P2X7 receptors in the periarticular tissues. On the other hand, PBM was able to increase protein level of IL-10 (anti-inflammatory cytokine). In summary, it is possible to suggest that PBM inhibit inflammatory chemotaxis, modulation the balance of the pro- and anti-inflammatory characteristics of inflammatory cells.

The impact of photobiomodulation on the chondrogenic potential of adipose-derived stromal/stem cells.

Due to their capacity to differentiate into the chondrogenic lineage, adipose-derived stromal/stem cells (ASC) are a promising source of therapeutically relevant cells for cartilage tissue regeneration. Their differentiation potential, however, varies between patients. In our study, we aim to stimulate ASC towards a more reliable chondrogenic phenotype using photobiomodulation (PBM). LED devices of either blue (475 nm), green (516 nm) or red (635 nm) light were used to treat human ASC from donors of varying chondrogenic potential. The treatment was applied either once during the 2D expansion phase or repeatedly during the 3D differentiation phase. Chondrogenic differentiation was assessed via pellet size, GAG/DNA content, histology and gene expression analysis. Reactions to PBM were found to be wavelength-dependent and more pronounced when the treatment was applied during expansion. Donors were assigned to responder categories according to their response to the treatment during expansion, whereby good responders were mainly donors with low intrinsic chondrogenic potential. Exposed to light, they revealed a particularly high relative increase in pellet size (more than twice the size of untreated controls after red light PBM), intense collagen type II immunostaining (low/absent in untreated controls) and activation of otherwise absent COL2A1 expression. Conversely, on a donor with high intrinsic chondrogenic potential, light had adverse effects. When applied with shorter wavelengths (blue, green), it led to reduced pellet size, GAG/DNA content and collagen type II immunostaining. However, when PBM was applied in 3D, the same donor was the only one to react with increased differentiation to all three wavelengths. We were able to demonstrate that PBM can be used to enhance or hamper chondrogenesis of ASC, and that success depends on treatment parameters and intrinsic cellular potential. The improvement of chondrogenesis in donors with low intrinsic potential highlights PBM as potent tool for cell-based cartilage regeneration. Its cost-effectiveness and ease of use make for an attractive treatment option to enhance the performance of ASC in cartilage tissue engineering.

miRNA-93 in Serum Extracellular Vesicles Before and After Low Dose Rate Prostate Brachytherapy.

BACKGROUND/AIM: To identify novel biomarkers for prostate cancer (PC), we evaluated changes of miRNAs contained in serum small extracellular vesicles (EVs) in patients who received low dose rate prostate brachytherapy (BT). MATERIALS AND METHODS: EVs were isolated from the pooled serum of 10 PC patients prior to and 1 month after BT. miRNA profiling and quantitation in EVs was performed by microarray analysis and RT-digital PCR, respectively. Expression of miRNA-93 in prostate tissue was evaluated using the TCGA database and its level in EVs was determined in 25 patients before and 1, 3, 6 and 12 months after BT. RESULTS: Profiling and quantitation identified miRNA-93 as significantly down-regulated in EVs after BT. TCGA database analysis showed that miRNA-93 was increased in PC tissue. miRNA-93 in EVs significantly decreased in 3, 6 and 12 months after BT. CONCLUSION: miRNA-93 contained in serum EVs may be a novel diagnostic and monitoring biomarker for PC.

Impact of aging on gene expression response to x-ray irradiation using mouse blood.

As a radiation biodosimetry tool, gene expression profiling is being developed using mouse and human peripheral blood models. The impact of dose, dose-rate, and radiation quality has been studied with the goal of predicting radiological tissue injury. In this study, we determined the impact of aging on the gene expression profile of blood from mice exposed to radiation. Young (2 mo) and old (21 mo) male mice were irradiated with 4 Gy x-rays, total RNA was isolated from whole blood 24 h later, and subjected to whole genome microarray analysis. Pathway analysis of differentially expressed genes revealed young mice responded to x-ray exposure by significantly upregulating pathways involved in apoptosis and phagocytosis, a process that eliminates apoptotic cells and preserves tissue homeostasis. In contrast, the functional annotation of senescence was overrepresented among differentially expressed genes from irradiated old mice without enrichment of phagocytosis pathways. Pathways associated with hematologic malignancies were enriched in irradiated old mice compared with irradiated young mice. The fibroblast growth factor signaling pathway was underrepresented in older mice under basal conditions. Similarly, brain-related functions were underrepresented in unirradiated old mice. Thus, age-dependent gene expression differences should be considered when developing gene signatures for use in radiation biodosimetry.

IRF1 regulates the progression of colorectal cancer via interferon­induced proteins.

Radiation is one of the main methods for the treatment of colorectal cancer (CRC) before or after surgery. However, radiotherapy tolerance of patients with CRC is often a major concern. Interferon regulatory factor 1 (IRF1) is a member of the IRF family and is involved in the development of multiple diseases, including tumors. The present study investigated the role of IRF1 in the development and radiation sensitivity of CRC. Immunohistochemistry was performed to examine the expression levels of IRF1 in tissue samples from patients with CRC, as well as in nude mice. MTT, 5­ethynyl­20­deoxyuridine, colony formation, cell cycle alteration and apoptosis assays were performed in CRC cell lines. Western blotting and immunofluorescence were used to detect the expression levels of a series of proteins. RNA sequencing was applied to identify genes whose expression was upregulated by IRF1 overexpression. Xenograft nude mouse models and hematoxylin and eosin staining were used to validate the present findings in vivo. It was revealed that the expression levels of IRF1 were significantly lower in CRC tissues than in adjacent tissues. IRF1 upregulation inhibited cell proliferation and colony formation, caused G1 cell arrest, promoted cell apoptosis, and enhanced the sensitivity of CRC cells to X­ray irradiation. The role of IRF1 in promoting the radiosensitivity of CRC was further demonstrated in nude mice with CRC xenografts. In addition, RNA sequencing revealed that overexpression of IRF1 in CRC cells significantly increased the expression levels of interferon­induced protein family members interferon α inducible protein 6, interferon induced transmembrane protein 1 and interferon induced protein 35 (fold change >2.0). In summary, the present study demonstrated that the upregulation of IRF1 inhibited the progression and promoted the radiosensitivity of CRC, likely by regulating interferon­induced proteins.

470 nm LED Irradiation Inhibits the Invasiveness of CD133-positive Human Colorectal Cancer Stem Cells by Suppressing the Cyclooxygenase-2/prostaglandin E2 Pathway.

BACKGROUND/AIM: Recurrence and metastasis of cancer caused by cancer stem cells (CSCs) is a challenge to overcome. Low level laser therapy is a new treatment strategy to suppress their invasiveness. We have assessed the inhibitory effects of 470 nm blue LED on the invasiveness of them to determine the molecular mechanisms of anti-invasiveness. MATERIALS AND METHODS: The effects of blue LEDs on their viability, proliferation and invasion were analyzed using MTT and transwell methods. In addition, the anti-invasiveness effect of blue LED on them was evaluated by zymography, semi-quantitative RT-PCR and western blot analysis. RESULTS: Irradiation with blue LED at 3 J/cm2 resulted in inhibition of their viability, proliferation and invasiveness. Their matrix metalloproteinase 2 (MMP-2) and MMP-9 activities were reduced by blue LED irradiation. Semi-quantitative RT-PCR also showed similar results. In addition, western blotting analyses showed that cyclooxygenase-2 (COX-2) and prostaglandin E2 (PGE2) synthesis were significantly inhibited by LED irradiation in CD133+ colorectal CSCs. CONCLUSION: Down-regulation of the COX-2/PGE2 signaling pathway by blue LED irradiation led to reduce expression of MMP-2 and MMP-9, inhibiting the invasiveness of CD133+ colorectal CSC.

A 2-pyridone modified zinc phthalocyanine with three-in-one multiple functions for photodynamic therapy.

A 2-pyridone modified zinc phthalocyanine (denoted ZnPc-PYR) achieves a one stone for three birds outcome in the photodynamic therapy (PDT) treatment of cancer. ZnPc-PYR can be excited by both 665 and 808 nm light to treat superficial and deep tumors, store and slowly release singlet oxygen (1O2) to improve its utilization and downregulate the HIF-1 (hypoxia-inducible factor 1) expression level to enhance the tumor cell's sensitivity to PDT treatment under hypoxic conditions.

MiR-34a reverses radiation resistance on ECA-109 cells by inhibiting PI3K/AKT/mTOR signal pathway through downregulating the expression of SIRT1.

BACKGROUND: Radiotherapy is an effective treatment for esophageal squamous cell carcinoma (ESCC). However, many ESCC patients relapsed after receiving radiotherapy due to the inherent resistance. The function of miR-34a and SIRT1, as well as the correlation between miR-34a and SIRT1 has been widely claimed in multiple types of malignant tumors. This study aimed to investigate the effects of miR-34a on radiation resistance against ESCC and the underlying mechanism. METHODS: In this study, CCK8, flow cytometry, wounding healing assays, and cell clone formation assay were used to determine the in vitro anti-tumor effects of radiation on radiation-resistant ESCC cell line (rECA-109). The luciferase activity and Western Blot assays were used to investigate the relationship among miR-34a, SIRT1, and the anti-radiation resistant effects. The xenograft experiments were used to verify the important function of miR-34a and SIRT1 in radiation resistance against ESCC. The apoptosis state of tumor tissues was evaluated by TUNEL assay. RESULTS: The introduction of miR-34a significantly induced the cell death and apoptosis of rECA-109 and inhibit the migration of rECA-109 treated by radiation. The anti-tumor effect was accompanied by the downregulation of SIRT1 and the inhibition of PI3K/AKT/mTOR signal pathway. The radiation resistance on rECA-109 cells was reversed by silencing SIRT1, accompanied by the PI3K/AKT/mTOR signal pathway inhibited. In vivo experiments revealed that the radiation resistance on ESCC was reversed by the introduction of miR-34a, the effect of which was promoted by the activation of SIRT1. CONCLUSION: Our results showed that miR-34a could reverse the radiation resistance on rECA-109 cells by downregulating the expression of SIRT1through inhibiting the PI3K-AKT-mTOR signal pathway.

Down-regulation of autophagy-associated protein increased acquired radio-resistance bladder cancer cells sensitivity to taxol.

BACKGROUND: As a bladder-preserving therapy, radiation therapy (RT) has been widely used in the treatment of bladder cancer (BCa) and made great progress in the past few decades. However, some BCa patients have low RT responsiveness and local recurrence rate after RT could reach 50%. Acquired radio-resistance (ARR) is one of the important reasons for the failure of RT. Unfortunately, these ARR cells also lack sensitivity to chemotherapy and cause tumor recurrence and metastasis. PURPOSE: To build ARR-phenotype BCa cell model, discuss the possible molecular mechanism of ARR and find effective target molecules to overcome ARR. MATERIALS AND METHODS: Five thousand six hundred and thirty-seven cells were subjected 30 times to 2 Gy of γ-rays and the surviving cells were called 5637R. Colony formation and MTT assay were applied to evaluate cells sensitivity to ionizing radiation (IR) and anti-neoplastic agents, respectively. Cells abilities of migration and invasion were determined using transwell method. Quantitative real-time polymerase chain reaction (RT-qPCR) and western blot (WB) were respectively utilized to compare the difference of gene and protein expression between 5637 and 5637R cells. Molecule inhibitors and small interfering RNA (siRNA) systems were employed to decrease the expression of target proteins, respectively. RESULTS: BCa cells survived from fractionated irradiation (FI) exhibited tolerance to both IR and chemotherapy drugs. These ARR cells (5637R) had elevated migration and invasion abilities, accompanied by increased expression of epithelial mesenchymal transition (EMT)-related transcription factors (ZEB1/Snail/Twist). Moreover, 5637R cells showed enhanced cancer stem cell (CSC)-like characteristics with activated KMT1A-GATA3-STAT3 circuit, a newly reported self-renewal pathway of human bladder cancer stem cell (BCSC). Combined with Kaplan-Meier's analysis, we speculated that GATA3/MMP9/STAT3 could be an effective molecular panel predicting poor prognosis of BCa. In order to enhance the sensitivity of resistant cells to radiation, we introduced ERK inhibitor (FR 180204) and STAT3 inhibitor (S3I-201). However, both of them could not enhance ARR cells response to IR. On the other hand, siRNAs were respectively implemented to inhibit the expression of endogenous Beclin1 and Atg5, two important autophagy-related genes, in BCa cells, which significantly increased 5637R cells death upon taxol exposing. Similarly, chloroquine (CQ), a classic autophagy inhibitor, enhanced the cytotoxicity of taxol only on 5637R cells. CONCLUSIONS: Long-term FI treatment is an effective method to establish the ARR-phenotype BCa cell model, by enriching BCSCs and enhancing cells migration and invasion. Both inhibiting the expression of autophagy-related proteins and using autophagy inhibitor can increase the sensitivity of ARR cells to taxol, suggesting that autophagy may play an important role in ARR cells chemical tolerance.

Inhibition of EphA2 by Dasatinib Suppresses Radiation-Induced Intestinal Injury.

Radiation-induced multiorgan dysfunction is thought to result primarily from damage to the endothelial system, leading to a systemic inflammatory response that is mediated by the recruitment of leukocytes. The Eph-ephrin signaling pathway in the vascular system participates in various disease developmental processes, including cancer and inflammation. In this study, we demonstrate that radiation exposure increased intestinal inflammation via endothelial dysfunction, caused by the radiation-induced activation of EphA2, an Eph receptor tyrosine kinase, and its ligand ephrinA1. Barrier dysfunction in endothelial and epithelial cells was aggravated by vascular endothelial-cadherin disruption and leukocyte adhesion in radiation-induced inflammation both in vitro and in vivo. Among all Eph receptors and their ligands, EphA2 and ephrinA1 were required for barrier destabilization and leukocyte adhesion. Knockdown of EphA2 in endothelial cells reduced radiation-induced endothelial dysfunction. Furthermore, pharmacological inhibition of EphA2-ephrinA1 by the tyrosine kinase inhibitor dasatinib attenuated the loss of vascular integrity and leukocyte adhesion in vitro. Mice administered dasatinib exhibited resistance to radiation injury characterized by reduced barrier leakage and decreased leukocyte infiltration into the intestine. Taken together, these data suggest that dasatinib therapy represents a potential approach for the protection of radiation-mediated intestinal damage by targeting the EphA2-ephrinA1 complex.

Biological Effects of Hyaluronic Acid-Based Dermal Fillers and Laser Therapy on Human Skin Models.

Injection of dermal fillers is one of the most frequently performed aesthetic procedures. The aim of the present study was to investigate the biological effects of different stabilized hyaluronan (HA) and poly-l-lactic acid fillers with and without subsequent additional fractional laser co-treatment on skin morphology and gene expression. Intradermal injection resulted in a significant enhancement of epidermal thickness detected by histological analysis. Combining HA fillers with ablative fractional CO2- or Er:YAG laser irradiation enhanced this effect. Gene expression profiling revealed an upregulation of modulators of tissue remodeling (eg TIMP3, SERPIN E1) and collagens (COL11A1). On the other hand, we detected a downregulation of differentiation markers (eg FLG, LOR, KRT1) and proinflammatory cytokines (eg IL-36, IL-1β). Interestingly, HA-based fillers revealed a specific upregulation pattern of chemokines such as CXCL5 andCCL20 suggesting a secondary effect of these fillers on the immune cells of the skin, especially monocytes and macrophages. Taken together, our data show enhancing effects of dermal fillers on epidermal thickness and prove the proliferating effects of these products on epidermal cells on the molecular level. Moreover, our findings reveal synergistic effects of fractional ablative laser treatment and HA dermal filler injection suggesting a combination of both treatments. J Drugs Dermatol. 2020;19(9):897-899. doi:10.36849/JDD.2020.4856.

A2A adenosine receptors are involved in the reparative response of tendon cells to pulsed electromagnetic fields.

Tendinopathy is a degenerative disease in which inflammatory mediators have been found to be sometimes present. The interaction between inflammation and matrix remodeling in human tendon cells (TCs) is supported by the secretion of cytokines such as IL-1ß, IL-6 and IL-33. In this context, it has been demonstrated that pulsed electromagnetic fields (PEMFs) were able to reduce inflammation and promote tendon marker synthesis. The aim of this study was to evaluate the anabolic and anti-inflammatory PEMF-mediated response on TCs in an in vitro model of inflammation. Moreover, since PEMFs enhance the anti-inflammatory efficacy of adenosine through the adenosine receptors (ARs), the study also focused on the role of A2AARs. Human TCs were exposed to PEMFs for 48 hours. After stimulation, A2AAR saturation binding experiments were performed. Along with 48 hours PEMF stimulation, TCs were treated with IL-1ß and A2AAR agonist CGS-21680. IL-1Ra, IL-6, IL-8, IL-10, IL-33, VEGF, TGF-ß1, PGE2 release and SCX, COL1A1, COL3A1, ADORA2A expression were quantified. PEMFs exerted A2AAR modulation on TCs and promoted COL3A1 upregulation and IL-33 secretion. In presence of IL-1ß, TCs showed an upregulation of ADORA2A, SCX and COL3A1 expression and an increase of IL-6, IL-8, PGE2 and VEGF secretion. After PEMF and IL-1ß exposure, IL-33 was upregulated, whereas IL-6, PGE2 and ADORA2A were downregulated. These findings demonstrated that A2AARs have a role in the promotion of the TC anabolic/reparative response to PEMFs and to IL-1ß.

Biomarker function of HMGA2 in ultraviolet-induced skin cancer development.

The high mobility group AT-hook 2 (HMGA2) gene encodes a transcription factor that is expressed during embryonic development but down-regulated in adult tissues. Its re-expression in adult tissues is often associated with tumorigenesis. In this study, we found that HMGA2 is highly expressed in human cutaneous squamous cell carcinoma (SCC) cell lines and primary SCC tumors, but not in adjacent normal skin. In non-ultraviolet (UV)-irradiated mouse skin, baseline Hmga2 expression was detected in the epidermis but not in hair follicles. Following chronic UV exposure, we found activation of Hmga2 in hair follicles. UV-induced mouse skin SCC tumors displayed a ubiquitous increase in Hmga2 expression compared to non-tumor-bearing adjacent skin. In human SCC cells, decreased HMGA2 expression was linked with reduced cell proliferation following depletion of FOXM1 and TRIP13, two UV master regulator genes. Taken together, these findings highlight an important biomarker function of HMGA2 expression in UV-induced skin tumorigenesis and cell proliferation.

Low­intensity low­frequency ultrasound enhances the chemosensitivity of gemcitabine­resistant ASPC­1 cells via PI3K/AKT/NF­κB pathway­mediated ABC transporters.

Tumor drug resistance (TDR) invariably leads to the failure of chemotherapy. In addition, current treatment strategies for TDR are not satisfactory due to limitations in terms of safety and feasibility. The aim of the present study was to determine whether low­intensity low­frequency ultrasound (LILFU) could improve the effect of chemotherapy and reverse TDR in gemcitabine­resistant ASPC­1 (ASPC­1/GEM) cells. The investigation focused on the association between LILFU effectiveness and the adenosine triphosphate­binding cassette (ABC) transporters and the phosphoinositide 3­kinase (PI3K)/protein kinase B (AKT)/nuclear factor (NF)­κB signaling pathway. A Cell Counting Kit­8 assay was used to determine the appropriate acoustic intensity, half­maximal inhibitory concentration of gemcitabine (GEM) and the viability of ASPC­1/GEM cells. ASPC­1/GEM cells were divided into control, GEM, LILFU and GEM+LILFU groups. Cell proliferation was evaluated through colony formation assays, whereas cell apoptosis was detected using flow cytometry. Western blotting was used to explore the expression levels of ABC transporters and PI3K/AKT/NF­κB signaling pathway­associated proteins. Xenograft models in mice were established to identify the enhancing effect of GEM+LILFU in vivo. Immunohistochemistry was used to detect the expression levels of Ki­67 in tumor tissues. The acoustic parameter of 0.2 W/cm2 and a GEM concentration of 6.63 mg/ml were used in subsequent experiments. Following treatment with GEM+LILFU, the cell viability and proliferation ability were decreased, whereas the apoptotic rate was increased compared with the GEM group. The expression levels of ABC transporters, PI3K­P110α and NF­κB were decreased in the GEM+LILFU group. Notably, LILFU increased the effectiveness of GEM in inhibiting tumor growth, and reduced the expression levels of Ki­67 in the xenograft mouse model. LILFU improved the chemosensitivity of ASPC­1/GEM cells via inhibition of cell viability and proliferation, and promoted cell apoptosis in the GEM+LILFU group. In conclusion, LILFU may downregulate the expression levels of ABC transporters by inhibiting the PI3K­p110α/AKT/NF­κB signaling pathway, thereby reversing resistance in pancreatic cancer.

Downregulation of RKIP promotes radioresistance of nasopharyngeal carcinoma by activating NRF2/NQO1 axis via downregulating miR-450b-5p.

Dysregulation of RKIP and NRF2 has been widely involved in the therapy resistance of multiple malignances, however, their relation and the corresponding mechanisms, especially in radiation response, have not been elucidated. In this study, we revealed that RKIP could negatively regulate the expression of NRF2 in nasopharyngeal carcinoma (NPC) cells. Depletion or ectopic expression of NRF2 countered the pro- or anti- radioresistant effects of RKIP knockdown or overexpression on NPC cells, respectively, both in vitro and in vivo. Furthermore, our results indicated that NQO1 was positively regulated by NRF2 and served as the downstream effector of RKIP/NRF2 axis in regulation of NPC radioresistance. Mechanistically, miR-450b-5p, being positively regulated by RKIP in NPC cells, could sensitize NPC cells to irradiation by directly targeting and suppressing the level of NRF2. Besides, we analyzed the level of aforementioned molecules in NPC tissues. The results indicated that RKIP was significantly downregulated, NRF2 and NQO1 were notably upregulated in NPC tissues compared with in normal nasopharyngeal mucosa (NNM) tissues. Furthermore, RKIP and miR-450b-5p were remarkably lower, yet NRF2 and NQO1 were notably higher, in radioresistant NPC tissues relative to in radiosensitive NPC tissues. Consistent with the pattern in NPC cells, the RKIP/miR-450b-5p/NRF2/NQO1 axis was significantly correlated in NPC tissues. Downregulation of RKIP and miR-450b-5p, and upregulation of NRF2 and NQO1, positively correlated to malignant pathological parameters such as primary T stage, Lymph node (N) metastasis, and TNM stage. Finally, RKIP and miR-450b-5p served as favorable prognostic indicators, and NRF2 and NQO1 acted as unfavorable prognostic biomarkers in patients with NPC. Collectively, our outcomes reveal that RKIP downregulation promotes radioresistance of NPC by downregulating miR-450b-5p and subsequently upregulating and activating NRF2 and NQO1, highlighting RKIP/miR-450b-5p/NRF2/NQO1 axis as a potential therapeutic target for improving the radiosensitivity of NPC.

Radiation Triggers a Dynamic Sequence of Transient Microglial Alterations in Juvenile Brain.

Cranial irradiation (IR), an effective tool to treat malignant brain tumors, triggers a chronic pro-inflammatory microglial response, at least in the adult brain. Using single-cell and bulk RNA sequencing, combined with histology, we show that the microglial response in the juvenile mouse hippocampus is rapid but returns toward normal within 1 week. The response is characterized by a series of temporally distinct homeostasis-, sensome-, and inflammation-related molecular signatures. We find that a single microglial cell simultaneously upregulates transcripts associated with pro- and anti-inflammatory microglial phenotypes. Finally, we show that juvenile and adult irradiated microglia are already transcriptionally distinct in the early phase after IR. Our results indicate that microglia are involved in the initial stages but may not be responsible for driving long-term inflammation in the juvenile brain.

5-aminolevulinic-acid-mediated sonodynamic therapy improves the prognosis of melanoma by inhibiting survivin expression.

BACKGROUND: This study aimed to evaluate the relationship between survivin expression and melanoma after 5-aminolevulinic acid (5-ALA)-mediated sonodynamic therapy. METHODS: Immunohistochemistry was used to detect survivin protein expression in human melanoma clinical samples. Subsequently, the effects of 5-ALA-mediated sonodynamic therapy were determined by measuring the volume of melanoma xenografts and the bodyweights of melanoma-bearing nude mice. The MTT assay was used to detect the viability of melanoma B16-F10 cells under the action of 5-ALA-mediated sonodynamic therapy, and Western blotting and PCR were used to detect survivin expression in melanoma cells and in the melanoma-xenograft model. RESULTS: Survivin expression was significantly upregulated in human melanoma tissues compared with that of non-melanoma tissues. In the in vivo case, 5-ALA-mediated sonodynamic therapy significantly delayed tumor growth, prolonged the survival of mice, and inhibited the expression of survivin. In the in vitro case, 5-ALA-mediated sonodynamic therapy inhibited B16-F10 cell proliferation and decreased survivin expression at both protein and mRNA levels. CONCLUSION: Our results suggest that 5-ALA-mediated sonodynamic therapy inhibited B16-F10 cell proliferation and melanoma-xenograft growth and prolonged survival of melanoma-bearing nude mice, which might be through downregulation of survivin expression.