1.7 GHz long-term evolution radiofrequency electromagnetic field with stable power monitoring and efficient thermal control has no effect on the proliferation of various human cell types.

Long-term evolution (LTE) radiofrequency electromagnetic field (RF-EMF) is widely used in communication technologies. Thus, the influence of RF-EMF on biological systems is a major public concern and its physiological effects remain controversial. In our previous study, we showed that continuous exposure of various human cell types to 1.7 GHz LTE RF-EMF at a specific absorption rate (SAR) of 2 W/Kg for 72 h can induce cellular senescence. To understand the precise cellular effects of LTE RF-EMF, we elaborated the 1.7 GHz RF-EMF cell exposure system used in the previous study by replacing the RF signal generator and developing a software-based feedback system to improve the exposure power stability. This refinement of the 1.7 GHz LTE RF-EMF generator facilitated the automatic regulation of RF-EMF exposure, maintaining target power levels within a 3% range and a constant temperature even during the 72-h-exposure period. With the improved experimental setup, we examined the effect of continuous exposure to 1.7 GHz LTE RF-EMF at up to SAR of 8 W/Kg in human adipose tissue-derived stem cells (ASCs), Huh7, HeLa, and rat B103 cells. Surprisingly, the proliferation of all cell types, which displayed different growth rates, did not change significantly compared with that of the unexposed controls. Also, neither DNA damage nor cell cycle perturbation was observed in the 1.7 GHz LTE RF-EMF-exposed cells. However, when the thermal control system was turned off and the subsequent temperature increase induced by the RF-EMF was not controlled during continuous exposure to SAR of 8 W/Kg LTE RF-EMF, cellular proliferation increased by 35.2% at the maximum. These observations strongly suggest that the cellular effects attributed to 1.7 GHz LTE RF-EMF exposure are primarily due to the induced thermal changes rather than the RF-EMF exposure itself.

Ultraviolet Light-Emitting Diode Radiation Kills Leukemia Cells Without Affecting Hematopoiesis of Hematopoietic Stem Cells in Mice.

OBJECTIVES: The eradication of leukemia cells while sparing hematopoietic stem cells in the graft before autologous hematopoietic stem cell transplant is critical to prevention of leukemia relapse. Proliferating cells have been shown to be more prone to apoptosis than differentiated cells in response to ultraviolet radiation; however, whether leukemia cells are more sensitive to ultraviolet LED radiation than hematopoietic stem cells remains unclear. MATERIALS AND METHODS: We compared the in vitro responses between murine leukemia L1210 cells and murine hematopoietic stem cells to 280-nm ultraviolet LED radiation. We also investigated the effects of ultraviolet LED radiation on the tumorigenic and metastatic capacity of L1210 cells and hematopoietic stem cell hematopoiesis in a mouse model of hematopoietic stem cell transplant. RESULTS: L1210 cells were more sensitive to ultraviolet LED radiation than hematopoietic stem cells in vitro, as evidenced by significantly reduced colony formation rates and cell proliferation rates, along with remarkably increased apoptosis rates in L1210 cells. Compared with corresponding unirradiated cells, ultraviolet LED-irradiated L1210 cells failed to generate palpable tumors in mice, whereas ultraviolet LED-irradiated bone marrow cells restored hematopoiesis in vivo. Furthermore, transplant with an irradiated mixture of L1210 cells and bone marrow cells showed later onset of leukemia, milder leukemic infiltration, and prolonged survival in mice, compared with unirradiated cell transplant. CONCLUSIONS: Our results suggest that ultraviolet LED radiation can suppress the proliferative and tumorigenic abilities of leukemia cells without reducing the hematopoietic reconstitution capacity of hematopoietic stem cells, serving as a promising approach to kill leukemia cells in autograft before autologous hematopoietic stem cell transplant.

LPA5-Dependent signaling regulates regeneration of the intestinal epithelium following irradiation.

Lysophosphatidic acid (LPA) is a bioactive lipid molecule that regulates a wide array of cellular functions, including proliferation, differentiation, and survival, via activation of cognate receptors. The LPA5 receptor is highly expressed in the intestinal epithelium, but its function in restoring intestinal epithelial integrity following injury has not been examined. Here, we use a radiation-induced injury model to study the role of LPA5 in regulating intestinal epithelial regeneration. Control mice (Lpar5f/f) and mice with an inducible, epithelial cell-specific deletion of Lpar5 in the small intestine (Lpar5IECKO) were subjected to 10 Gy total body X-ray irradiation and analyzed during recovery. Repair of the intestinal mucosa was delayed in Lpar5IECKO mice with reduced epithelial proliferation and increased crypt cell apoptosis. These effects were accompanied by reduced numbers of OLFM4+ intestinal stem cells (ISCs). The effects of LPA5 on ISCs were corroborated by studies using organoids derived from Lgr5-lineage tracking reporter mice with deletion of Lpar5 in Lgr5+-stem cells (Lgr5Cont or Lgr5ΔLpar5). Irradiation of organoids resulted in fewer numbers of Lgr5ΔLpar5 organoids retaining Lgr5+-derived progenitor cells compared with Lgr5Cont organoids. Finally, we observed that impaired regeneration in Lpar5IECKO mice was associated with reduced numbers of Paneth cells and decreased expression of Yes-associated protein (YAP), a critical factor for intestinal epithelial repair. Our study highlights a novel role for LPA5 in regeneration of the intestinal epithelium following irradiation and its effect on the maintenance of Paneth cells that support the stem cell niche.NEW & NOTEWORTHY We used mice lacking expression of the lysophosphatidic acid receptor 5 (LPA5) in intestinal epithelial cells and intestinal organoids to show that the LPA5 receptor protects intestinal stem cells and progenitors from radiation-induced injury. We show that LPA5 induces YAP signaling and regulates Paneth cells.

Differences in the response of normal oral mucosa, oral leukoplakia, oral squamous cell carcinoma-derived mesenchymal stem cells, and epithelial cells to photodynamic therapy.

OBJECTIVE: The objective of this study is to investigate the variances in transcriptome gene expression of normal oral mucosa-derived mesenchymal stem cell (OM-MSC), oral leukoplakia-derived MSC (OLK-MSC) and oral squamous cell carcinoma-derived MSC(OSCC-MSC). as Additionally, the study aims to compare the in vitro proliferation, migration, invasion ability, and response to photodynamic therapy (PDT) of these three MSC, HOK, DOK, leuk1, and Cal27 cell lines. METHODS: HOK, DOK, leuk1, Cal27 cells were cultured in vitro. 3 MSC cells were obtained from OM, OLK, OSCC tissue (n = 3) and identified through flow cytometry. They were also cultured in vitro for osteogenic and lipogenic-induced differentiation. Based on the Illumina HiSeq high-throughput sequencing platform, OM-MSC, OLK-MSC, OSCC-MSC (n = 3) were subjected to transcriptome sequencing, functional annotation, and enrichment analysis of differentially expressed genes and related genes. CCK8 assay, wound healing assay, and transwell assay were performed to compare the proliferation, migration, and invasion of the seven types of cells. The 7 cells were incubated with 0, 0.125 mM, 0.25 mM, 0.5 mM, 1 mM, and 2 mM of the photosensitizer (5-aminolevulinic acid, 5-ALA) in vitro. Subsequently, they were irradiated with a 150 mM, 635 nm laser for 1 min, and the cell activity was detected using the CCK8 assay after 24 h. The mitochondrial changes in the 7 cells before and after the treatment of PDT were detected using the JC-10 probe, and the changes in ATP content were measured before and after the PDT treatment. RESULTS: OM-MSC, OLK-MSC, and OSCC-MSC expressed positive MSC surface markers. After osteogenic and lipogenic-induced differentiation culture, stained calcium nodules and lipid droplets were visible, meeting the identification criteria of MSC. Pathway enrichment analysis revealed that the differentially expressed genes (DEGs) of OSCC-MSC compared to OLK-MSC were primarily associated with the PI3K-Akt signaling pathway and tumor-related pathways. OSCC-MSC exhibited stronger migratory and invasive abilities compared to Cal27. The IC50 values required for OM, OLK, and OSCC-derived MSC were lower than those required for epithelial cells treated with PDT, which were 1.396 mM, 0.9063 mM, and 2.924 mM, respectively. Cell membrane and mitochondrial disruption were observed in seven types of cells after 24 h of PDT treatment. However, HOK, DOK, leuk1, and Cal27 cells had an ATP content increased. CONCLUSIONS: OLK, OSCC epithelial cells require higher concentrations of 5-ALA for PDT treatment than MSC of the same tissue origin. The concentration of 5-ALA required increases with increasing cell malignancy. Differences in the response of epithelial cells and MSC to PDT treatment may have varying impacts on OLK recurrence and malignancy.

Senescent characteristics of human corneal endothelial cells upon ultraviolet-A exposure.

PURPOSE: The objective of this study was to investigate the senescent phenotypes of human corneal endothelial cells (hCEnCs) upon treatment with ultraviolet (UV)-A. METHODS: We assessed cell morphology, senescence-associated ß-galactosidase (SA-ß-gal) activity, cell proliferation and expression of senescence markers (p16 and p21) in hCEnCs exposed to UV-A radiation, and senescent hCEnCs induced by ionizing radiation (IR) were used as positive controls. We performed RNA sequencing and proteomics analyses to compare gene and protein expression profiles between UV-A- and IR-induced senescent hCEnCs, and we also compared the results to non-senescent hCEnCs. RESULTS: Cells exposed to 5 J/cm2 of UV-A or to IR exhibited typical senescent phenotypes, including enlargement, increased SA-ß-gal activity, decreased cell proliferation and elevated expression of p16 and p21. RNA-Seq analysis revealed that 83.9% of the genes significantly upregulated and 82.6% of the genes significantly downregulated in UV-A-induced senescent hCEnCs overlapped with the genes regulated in IR-induced senescent hCEnCs. Proteomics also revealed that 93.8% of the proteins significantly upregulated in UV-A-induced senescent hCEnCs overlapped with those induced by IR. In proteomics analyses, senescent hCEnCs induced by UV-A exhibited elevated expression levels of several factors part of the senescence-associated secretory phenotype. CONCLUSIONS: In this study, where senescence was induced by UV-A, a more physiological stress for hCEnCs compared to IR, we determined that UV-A modulated the expression of many genes and proteins typically altered upon IR treatment, a more conventional method of senescence induction, even though UV-A also modulated specific pathways unrelated to IR.

Regulation of cellular responses to X-ray irradiation through the activation of lysophosphatidic acid (LPA) receptor-3 (LPA3) and LPA2 in osteosarcoma cells.

Lysophosphatidic acid (LPA) binds to its specific G protein-coupled LPA receptors (LPA1 to LPA6), resulting in the activation of various cellular functions. LPA receptor-mediated signaling facilitates tumor progression in human malignancies. In the present study, we investigated whether LPA receptor-mediated signaling contributes to cellular responses to X-ray irradiation in osteosarcoma MG-63 cells. After X-ray irradiation (2, 4 and 8 Gy), LPAR2 and LPAR3 expression levels in MG-63 cells were significantly elevated in a dose-dependent manner, but no change of LPAR1 expression level was observed. The cell growth activities of MG-63 cells irradiated with X-rays (2, 4 and 8 Gy) were reduced by LPA. Conversely, LPA3 agonist (2 S)-OMPT enhanced the cell growth activities of X-ray irradiated MG-63 cells. The cell movement of MG-63 cells exposed to X-ray irradiation (8 Gy) was inhibited by (2 S)OMPT. In cell survival assay, (2 S)-OMPT suppressed the cell survival to cisplatin (CDDP) of MG-63 cells irradiated with X-rays (8 Gy). The cell survival to CDDP of X-ray irradiated cells was elevated by LPA3 knockdown. Moreover, we evaluated the effects of LPA2 on the cell survival to CDDP of MG-63 cells exposed to X-ray irradiation (8 Gy). The cell survival to CDDP of X-ray irradiated cells was increased by LPA2 agonist GRI-977143 and reduced by LPA2 knockdown. These results suggest that LPA receptor-signaling participates in the modulation of cellular functions induced by X-ray irradiation in osteosarcoma cells.

Quetiapine Significantly Improves the Effectiveness of Radiotherapy in Combating Hepatocellular Carcinoma Progression in a Hep3B Xenograft Mouse Model.

BACKGROUND/AIM: In hepatocellular carcinoma (HCC) treatment, radiotherapy (RT) stands as a pivotal approach, yet the emergence of radioresistance poses a formidable challenge. This study aimed to explore the potential synergy between quetiapine and RT for HCC treatment. MATERIALS AND METHODS: A Hep3B xenograft mouse model was used, the investigation tracked tumor progression, safety parameters, and molecular mechanisms. RESULTS: The findings revealed a synergistic anti-HCC effect when quetiapine was coupled with RT that prolonged tumor growth time and a significantly higher growth inhibition rate compared to the control group. Safety assessments indicated minimal pathological changes, suggesting potential of quetiapine in mitigating RT-induced alterations in liver and kidney functions. Mechanistically, the combination suppressed metastasis and angiogenesis-related proteins, while triggering the activation of apoptosis-related proteins via targeting Epidermal growth factor receptor (EGFR)-mediated signaling. CONCLUSION: The potential of the quetiapine and RT combination is emphasized, offering enhanced anti-HCC efficacy, a safety profile, and positioning quetiapine as a radiosensitizer for HCC treatment.

Mammary tissue-derived extracellular matrix hydrogels reveal the role of irradiation in driving a pro-tumor and immunosuppressive microenvironment.

Radiation therapy (RT) is essential for triple negative breast cancer (TNBC) treatment. However, patients with TNBC continue to experience recurrence after RT. The role of the extracellular matrix (ECM) of irradiated breast tissue in tumor recurrence is still unknown. In this study, we evaluated the structure, molecular composition, and mechanical properties of irradiated murine mammary fat pads (MFPs) and developed ECM hydrogels from decellularized tissues (dECM) to assess the effects of RT-induced ECM changes on breast cancer cell behavior. Irradiated MFPs were characterized by increased ECM deposition and fiber density compared to unirradiated controls, which may provide a platform for cell invasion and proliferation. ECM component changes in collagens I, IV, and VI, and fibronectin were observed following irradiation in both MFPs and dECM hydrogels. Encapsulated TNBC cell proliferation and invasive capacity was enhanced in irradiated dECM hydrogels. In addition, TNBC cells co-cultured with macrophages in irradiated dECM hydrogels induced M2 macrophage polarization and exhibited further increases in proliferation. Our study establishes that the ECM in radiation-damaged sites promotes TNBC invasion and proliferation as well as an immunosuppressive microenvironment. This work represents an important step toward elucidating how changes in the ECM after RT contribute to breast cancer recurrence.

KTN1 mediated unfolded protein response protects keratinocytes from ionizing radiation-induced DNA damage.

BACKGROUND: The unfolded protein response (UPR) is one of the cytoprotective mechanisms against various stresses and essential for the normal function of skin. Skin injury caused by ionizing radiation (IR) is a common side effect of radiotherapy and it is unclear how UPR affects IR-induced skin injury. OBJECTIVES: To verify the effect of UPR on IR-induced DNA damage in keratinocytes and the relation between an endoplasmic reticulum (ER) protein KTN1 and UPR. METHODS: All experiments were performed on keratinocytes models: HaCaT and HEK-A. ER lumen and the expression levels of KTN1 and UPR pathway proteins (PERK, IRE1α and ATF6) were examined by transmission electron microscopy and immunoblotting, respectively. 4-PBA, an UPR inhibitor, was used to detected its effects on DNA damage and cell proliferation. Subsequently, the effects of KTN1 deletion on UPR, DNA damage and cell proliferation after IR were detected. Tunicamycin was used to reactivate UPR and then we examined its effects on DNA damage. RESULTS: UPR was activated by IR in keratinocytes. Inhibition of UPR aggravated DNA damage and suppressed cell proliferation after IR. KTN1 expression was upregulated by IR and KTN1 depletion reduced ER expansion and the expression of UPR-related proteins. Moreover, KTN1 depletion aggravated DNA damage and suppressed cell proliferation after IR could reversed by reactivation of UPR. CONCLUSION: KTN1 deletion aggravates IR-induced keratinocyte DNA damage via inhibiting UPR. Our findings provide new insights into the mechanisms of keratinocytes in response to IR-induced damage.

Effect of photobiomodulation on alleviating primary dysmenorrhea caused by PGF2α.

Photobiomodulation (PBM) has attracted widespread attention in suppressing various pain and inflammation. Primary dysmenorrhea (PD) primarily occurs in adolescents and adult females, and the limited effectiveness and side effects of conventional treatments have highlighted the urgent need to develop and identify new adjunct therapeutic strategies. In this work, the results of pain and PGs demonstrated that 850 nm, 630 nm, and 460 nm all exhibited pain inhibition, decreased PGF2α and upregulated PGE2, while 630 nm PBM has better effectiveness. Then to explore the underlying biological mechanisms of red light PBM on PD, we irradiated prostaglandin-F2α induced HUSM cells and found that low-level irradiance can restore intracellular calcium ion, ROS, ATP, and MMP levels to normal levels. And, red light enhanced cell viability and promoted cell proliferation for normal HUSM cells. Therefore, this study proposes that red light PBM may be a promising approach for the future clinical treatment of PD.

Comparison of Three Antagonists of Hedgehog Pathway to Promote Skeletal Muscle Regeneration after High Dose Irradiation.

The current geopolitical context has brought the radiological nuclear risk to the forefront of concerns. High-dose localized radiation exposure leads to the development of a musculocutaneous radiation syndrome affecting the skin and subcutaneous muscles. Despite the implementation of a gold standard treatment based on an invasive surgical procedure coupled with autologous cell therapy, a muscular defect frequently persists. Targeting the modulation of the Hedgehog (Hh) signaling pathway appears to be a promising therapeutic approach. Activation of this pathway enhances cell survival and promotes proliferation after irradiation, while inhibition by Cyclopamine facilitates differentiation. In this study, we compared the effects of three antagonists of Hh, Cyclopamine (CA), Vismodegib (VDG) and Sonidegib (SDG) on differentiation. A stable cell line of murine myoblasts, C2C12, was exposed to X-ray radiation (5 Gy) and treated with CA, VDG or SDG. Analysis of proliferation, survival (apoptosis), morphology, myogenesis genes expression and proteins production were performed. According to the results, VDG does not have a significant impact on C2C12 cells. SDG increases the expression/production of differentiation markers to a similar extent as CA, while morphologically, SDG proves to be more effective than CA. To conclude, SDG can be used in the same way as CA but already has a marketing authorization with an indication against basal cell cancers, facilitating their use in vivo. This proof of concept demonstrates that SDG represents a promising alternative to CA to promotes differentiation of murine myoblasts. Future studies on isolated and cultured satellite cells and in vivo will test this proof of concept.

Effects of low-level Er:YAG laser irradiation on proliferation and gene expression in primary gingival fibroblasts isolated from mouse maxilla.

We investigated the effects of low-level Er:YAG laser irradiation on proliferation and alternations in early gene expression of gingival fibroblasts. Mice primary gingival fibroblasts were irradiated with an Er:YAG laser (1.8, 3.9, and 5.8 J/cm2 ). Irradiation at 3.9 J/cm2 promoted cell proliferation without significant changes in lactate dehydrogenase or Hspa1a expression. Three hours after irradiation at 3.9 J/cm2 , the Fn1 expression level was significantly increased. RNA-seq identified 15 differentially expressed genes between irradiated and non-irradiated cells, some of which belonged to immediate early genes (IEGs). Kyoto Encyclopedia of Genes and Genomes pathway analysis indicated MAPK pathway enhancement, and gene set enrichment analysis showed enrichment in the TGF-ß signaling gene set. Enhanced proliferation via laser irradiation disappeared upon inhibition of Dusp4, Dusp5, and Tgfr1 expression. Low-level Er:YAG laser irradiation, especially at 3.9 J/cm2 without a major temperature elevation, enhanced fibroblast proliferation, via TGF-ß and the MAPK signaling pathway following IEG expression.

Photobiomodulation effects of pulsed and continuous wave near-infrared laser on the proliferation and migration of human gingival fibroblasts: An in vitro study.

There are limited data on comparison of pulsed and continuous wave in photobiomodulation therapy (PBM). This study aimed to investigate the effect of PBM with 980 nm laser in pulsed and continuous wave on the proliferation and migration of human gingival fibroblasts (HGF) cells. Cultured HGF were divided into three main groups: (1) irradiated in pulsed mode (frequencies of 50 and 25 KHz; energy densities of 3 and 5 J/cm2 ), (2) irradiated in continuous mode (energy densities of 3.2 and 5.2 J/cm2 ), and (3) no irradiation as control group. HGF proliferation rate was measured by MTT assay at 24, 48, and 72 h post irradiation. In addition, HGF migration rate was measured by scratch test at 24 h post PBM. At 24 h, the group received continuous irradiation at 5.2 J/cm2 showed significantly higher proliferation compared with the control group (p = 0.012). At 48 and 72 h, the groups received continuous, and 50 Hz pulsed irradiation at energy densities of 5.2 and 5 J/cm2 respectively, had significantly higher HGF proliferation rates compared to the control (p < 0.05). Only the continuous irradiations were effective in significant increase of the cell migration. In conclusion, continuous PBM at energy density of 5.2 J/cm2 showed promising effect on HGF proliferation and migration.

Proliferation and apoptosis after whole-body irradiation: longitudinal PET study in a mouse model.

PURPOSE: A reliable method for regional in vivo imaging of radiation-induced cellular damage would be of great importance for the detection of therapy-induced injury to healthy tissue and the choice of adequate treatment of radiation emergency patients in both civilian and military events. This study aimed to investigate in a mouse model if positron emission tomography (PET) imaging with proliferation and apoptosis markers is potentially suitable for this purpose. METHODS: Four groups, including twenty mice (wild-type C57BL/6) each, were whole-body irradiated with 0 Gy, 0.5 Gy, 1 Gy, and 3 Gy and examined by PET over a six-month period at defined time points. 3'-[18F]fluoro-3'-deoxythymidine ([18F]FLT) and 2-(5-[18F]fluoropentyl)-2-methyl malonic acid ([18F]ML-10) were used to visualise proliferation and apoptosis. Regional standard uptake values were compared with respect to irradiation dose over time. Histologic data and peripheral blood cell values were correlated with the PET results. RESULTS: The hematopoietic bone marrow showed a significantly increased [18F]FLT signal at early time points after radiation exposure (day 3 and day 7). This correlated with blood parameters, especially leukocytes, and histological data. A significantly increased [18F]FLT signal also occurred in the gastrointestinal tract and thymus at early time points. An increased [18F]ML-10 signal related to irradiation doses was observed in the bone marrow on day 8, but there was a high variability of standard uptake values and no correlation with histological data. CONCLUSION: [18F]FLT showed potential to visualise the extent, regional distribution and recovery from radiation-induced cellular damage in the bone marrow, gastrointestinal tract and thymus. The potential of [18F]FLT imaging to assess the extent of bone marrow affected by irradiation might be especially useful to predict the subsequent severity of hematopoietic impairment and to adapt the therapy of the bone marrow reserve. [18F]ML-10 PET proved to be not sensitive enough for the reliable detection of radiation induced apoptosis.

Photobiomodulation effects on fibroblasts and keratinocytes after ionizing radiation and bacterial stimulus.

OBJECTIVE: Photobiomodulation therapy (PBMT) has proven to reduce inflammation and pain and increase wound healing. Thus, the aim of this study was to analyze the effects of PBMT parameters on migration, proliferation, and gene expression after ionizing radiation and bacterial-induced stress in an in vitro study. DESIGN: Keratinocytes (HaCaT) and Fibroblasts (HGFs) were grown in DMEM with 10 % fetal bovine serum until stressful condition induction with lipopolysaccharide (LPS) of Escherichia coli (1 µg/mL), Porphyromonas gingivalis protein extract (5 µg/mL) and ionizing radiation (8 Gy). Low-laser irradiation (660 nm, 30 mW) was carried out in four sessions, with 6 h intervals, and energy density of 2, 3, 4, and 5 J/cm². Scratch assays, immunofluorescence, and RT-qPCR were performed. RESULTS: Treated fibroblasts and keratinocytes showed significant response in proliferation and migration after scratch assays (p < 0.05). Higher expressions of α-SMA in fibroblasts and F-actin in keratinocytes were observed in cells subjected to 3 J/cm². PI3K-pathway genes expression tended to enhance in fibroblasts, presenting a higher relative expression when compared to keratinocytes. In keratinocytes, PBMT groups demonstrated deregulated expression for all inflammatory cytokines' genes tested while fibroblasts presented a tendency to enhance those genes expression in a dose dependent way. CONCLUSIONS: The present study showed that delivering 660 nm, 30 mW was effective to stimulate cell migration, proliferation and to accelerate wound healing. PBMT can modulate cytokines and pathways involved in wound repair. The different energy densities delivering distinct responses in vitro highlights that understanding laser parameters is fundamental to improve treatment strategies.

Enhancing nasopharyngeal carcinoma cell radiosensitivity by suppressing AKT/mTOR via CENP-N knockdown.

OBJECTIVE: Investigating the impact of centromere protein N (CENP-N) on radiosensitivity of nasopharyngeal carcinoma (NPC) cells. METHODS: Using immunohistochemistry and immunofluorescence to detect CENP-N expression in tissues from 35 patients with radiosensitive or radioresistant NPC. Assessing the effect of combined CENP-N knockdown and radiotherapy on various cellular processes by CCK-8, colony formation, flow cytometry, and Western blotting. Establishing a NPC xenograft model. When the tumor volume reached 100 mm3, a irradiation dose of 6 Gy was given, and the effects of the combined treatment were evaluated in vivo using immunofluorescence and Western blotting techniques. RESULTS: The level of CENP-N was significantly reduced in radiosensitive tissues of NPC (p < 0.05). Knockdown of CENP-N enhanced NPC radiosensitivity, resulting in sensitizing enhancement ratios (SER) of 1.44 (5-8 F) and 1.16 (CNE-2Z). The combined treatment showed significantly higher levels of proliferation suppression, apoptosis, and G2/M phase arrest (p < 0.01) compared to either CENP-N knockdown alone or radiotherapy alone. The combined treatment group showed the highest increase in Bax and γH2AX protein levels, whereas the protein Cyclin D1 exhibited the greatest decrease (p < 0.01). However, the above changes were reversed after treatment with AKT activator SC79. In vivo, the mean volume and weight of tumors in the radiotherapy group were 182 ± 54 mm3 and 0.16 ± 0.03 g. The mean tumor volume and weight in the combined treatment group were 84 ± 42 mm3 and 0.04 ± 0.01 g. CONCLUSION: Knockdown of CENP-N can enhance NPC radiosensitivity by inhibiting AKT/mTOR.

Combined Aurora Kinase A and CHK1 Inhibition Enhances Radiosensitivity of Triple-Negative Breast Cancer Through Induction of Apoptosis and Mitotic Catastrophe Associated With Excessive DNA Damage.

PURPOSE: There is an urgent need for biomarkers and new actionable targets to improve radiosensitivity of triple-negative breast cancer (TNBC) tumors. We characterized the radiosensitizing effects and underlying mechanisms of combined Aurora kinase A (AURKA) and CHK1 inhibition in TNBC. METHODS AND MATERIALS: Different TNBC cell lines were treated with AURKA inhibitor (AURKAi, MLN8237) and CHK1 inhibitor (CHK1i, MK8776). Cell responses to irradiation (IR) were then evaluated. Cell apoptosis, DNA damage, cell cycle distribution, and mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) and Phosphoinositide 3-Kinase (PI3K) pathways were evaluated in vitro. Transcriptomic analysis was performed to facilitate the identification of potential biomarkers. Xenograft and immunohistochemistry were carried out to investigate the radiosensitizing effects of dual inhibition in vivo. Finally, the prognostic effect of CHEK1/AURKA in TNBC samples in the The Cancer Genome Atlas (TCGA) database and our center were analyzed. RESULTS: AURKAi (MLN8237) induced overexpression of phospho-CHK1 in TNBC cells. The addition of MK8776 (CHK1i) to MLN8237 greatly reduced cell viability and increased radiosensitivity compared with either the control or MLN8237 alone in vitro. Mechanistically, dual inhibition resulted in inducing excessive DNA damage by prompting G2/M transition to cells with defective spindles, leading to mitotic catastrophe and induction of apoptosis after IR. We also observed that dual inhibition suppressed the phosphorylation of ERK, while activation of ERK with its agonist or overexpression of active ERK1/2 allele could attenuate the apoptosis induced by dual inhibition with IR. Additionally, dual inhibition of AURKA and CHK1 synergistically enhanced radiosensitivity in MDA-MB-231 xenografts. Moreover, we detected that both CHEK1 and AURKA were overexpressed in patients with TNBC and negatively correlated with patient survival. CONCLUSIONS: Our findings suggested that AURKAi in combination with CHK1i enhanced TNBC radiosensitivity in preclinical models, potentially providing a novel strategy of precision treatment for patients with TNBC.

Partial liver irradiation in rats induces the hypertrophy of nonirradiated liver lobes through hepatocyte proliferation†.

Irradiation of the liver induces a regenerative response in the nonirradiated part of the liver. It is unclear whether this leads to actual liver enlargement. The aim of this study was to evaluate the weight of compensatory hypertrophy that occurs in nonirradiated livers and to clarify the mechanism of hypertrophy from the viewpoint of hepatocyte proliferation. The anterior liver lobes (anterior lobes) were irradiated with 60 Gy of X-rays (X60 Gy) under opening laparotomy. Body weights and liver lobe weights were measured before and at 1, 4, 8 and 12 weeks after irradiation, and serum and liver tissue samples were analyzed at each time point. The anterior lobes atrophied progressively, whereas the posterior liver lobes (posterior lobes) hypertrophied in the X-ray irradiated (X-irradiated) group. Although temporary liver damage was observed after irradiation, liver function did not decrease at any time point. Hepatocyte degeneration and loss were observed in the anterior lobes of the X-irradiated group, and significant fibrosis developed 8 weeks postirradiation. Following irradiation, the proportion of Ki-67-positive cells in the anterior lobes decreased markedly in the early postirradiation period, whereas the proportion of positive cells in the posterior lobes increased, peaking at 4 weeks postirradiation (P < 0.05). Increased tumor necrosis factor-α expression was observed only in the anterior liver lobes of the X-irradiated group at 1 and 4 weeks postirradiation. Partial liver irradiation with X60 Gy induced compensatory hypertrophy of nonirradiated liver lobes. This study suggests that liver hypertrophy after partial liver irradiation is caused by increased hepatocyte mitosis.

The effects of PKI-402 on breast tumor models' radiosensitivity via dual inhibition of PI3K/mTOR.

PURPOSE: PI3K/Akt/mTOR pathway activation causes relapse and resistance after radiotherapy in breast cancer (BC). We aimed to radiosensitize BC cell lines to irradiation (IR) by PKI-402, a dual PI3K/mTOR inhibitor. METHODS: We performed cytotoxicity, clonogenicity, hanging drop, apoptosis and double-strand break detection, and phosphorylation of 16 essential proteins involved in the PI3K/mTOR pathway. RESULTS: Our findings showed that PKI-402 has cytotoxic efficiency in all cell lines. Clonogenic assay results showed that PKI-402 plus IR inhibited the colony formation ability of MCF-7 and breast cancer stem cell lines. Results showed that PKI-402 plus IR causes more apoptotic cell death than IR alone in the MCF-7 cells but did not cause significant changes in the MDA-MB-231. γ-H2AX levels were increased in MDA-MB-231 in PKI-402 plus IR groups, whereas we did not observe any apoptotic and γ-H2AX induction in BCSCs and MCF-10A cells in all treatment groups. Some pivotal phosphorylated proteins of the PI3K/AKT pathway decreased, several proteins increased and others did not change. CONCLUSION: In conclusion, if the combined use of PKI-402 with radiation is supported by in vivo studies, it can contribute to the treatment options and the course of the disease.

Suppressing cancer by damaging cancer cell DNA using LED irradiation.

BACKGROUND: High-energy irradiation eliminates cancer cells by destroying their genetic components. However, there are several side effects from doing this, such as fatigue, dermatitis, and hair loss, which remain obstacles to this treatment. Here, we propose a moderate method that uses low-energy white light from a light-emitting diode (LED) to selectively inhibit cancer cell proliferation without affecting normal cells. METHODS: The association between LED irradiation and cancer cell growth arrest was evaluated based on cell proliferation, viability, and apoptotic activity. Immunofluorescence, polymerase chain reaction, and western blotting were performed in vitro and in vivo to identify the metabolism related to the inhibition of HeLa cell proliferation. RESULTS: LED irradiation aggravated the defective p53 signaling pathway and induced cell growth arrest in cancer cells. Consequently, cancer cell apoptosis was induced by the increased DNA damage. Additionally, LED irradiation inhibited the proliferation of cancer cells by suppressing the MAPK pathway. Furthermore, the suppression of cancer growth by the regulation of p53 and MAPK was observed in cancer-bearing mice irradiated with LED. CONCLUSIONS: Our findings suggest that LED irradiation can suppress cancer cell activity and may contribute to preventing the proliferation of cancer cells after medical surgery without causing side effects.