Radiosensitivity Of Cells Research Articles

TMT-Based Quantitative Proteomic Profiling of Human Esophageal Cancer Cells Reveals the Potential Mechanism and Potential Therapeutic Targets Associated With Radioresistance.

The recurrence of esophageal squamous cell carcinoma (ESCC) in radiation therapy treatment presents a complex challenge due to its resistance to radiation. However, the mechanism underlying the development of radioresistance in ESCC remains unclear. In this study, we aim to uncover the mechanisms underlying radioresistance in ESCC cells and identify potential targets for radiosensitization. We established two radio-resistant cell lines, TE-1R and KYSE-150R, from the parental ESCC cell lines TE-1 and KYSE-150 through fractionated irradiation. A TMT-based quantitative proteomic profiling approach was applied to identify changes in protein expression patterns. Cell Counting Kit-8, colony formation, γH2AX foci immunofluorescence and comet assays were utilized to validate our findings. The downstream effectors of the DNA repair pathway were confirmed using an HR/NHEJ reporter assay and Western blot analysis. Furthermore, we evaluated the expression of potential targets in ESCC tissues through immunohistochemistry combined with mass spectrometry. Over 2,000 proteins were quantitatively identified in the ESCC cell lysates. A comparison with radio-sensitive cells revealed 61 up-regulated and 14 down-regulated proteins in the radio-resistant cells. Additionally, radiation treatment induced 24 up-regulated and 12 down-regulated proteins in the radio-sensitive ESCC cells. Among the differentially expressed proteins, S100 calcium binding protein A6 (S100A6), glutamine gamma-glutamyltransferase 2 (TGM2), glycogen phosphorylase, brain form (PYGB), and Thymosin Beta 10 (TMSB10) were selected for further validation studies as they were found to be over-expressed in the accumulated radio-resistant ESCC cells and radio-resistant cells. Importantly, high S100A6 expression showed a positive correlation with cancer recurrence in ESCC patients. Our results suggest that several key proteins, including S100A6, TGM2, and PYGB, play a role in the development of radioresistance in ESCC. Our results revealed that several proteins including Protein S100-A6 (S100A6), Protein-glutamine gamma-glutamyltransferase 2 (TGM2), Glycogen phosphorylase, brain form (PYGB) were involved in radio-resistance development. These proteins could potentially serve as biomarkers for ESCC radio-resistance and as therapeutic targets to treat radio-resistant ESCC cells.

Retracted] hsa‑miR‑212 modulates the radiosensitivity of glioma cells by targeting BRCA1.

Following the publication of the above paper, it was drawn to the Editor's attention by a concerned reader that there appeared to be overlapping sections in a pair of the fluorescence reporter assay data panels shown in Fig. 4B; moreover, upon having conducted an independent investigation of the data in this paper in the Editorial Office, one of the data panels shown in this figure was strikingly similar to data that had previously appeared in different form in a paper written by different authors at a different research institute. Owing to the fact that the contentious data in the above article had already been published prior to its submission to Oncology Reports, the Editor has decided that this paper should be retracted from the Journal. The authors were asked for an explanation to account for these concerns, but the Editorial Office did not receive a satisfactory reply. The Editor apologizes to the readership for any inconvenience caused. [Oncology Reports 39: 977‑984, 2018; DOI: 10.3892/or.2017.6156].

Inhibition of ATM or ATR in combination with hypo-fractionated radiotherapy leads to a different immunophenotype on transcript and protein level in HNSCC.

The treatment of head and neck tumors remains a challenge due to their reduced radiosensitivity. Small molecule kinase inhibitors (smKI) that inhibit the DNA damage response, may increase the radiosensitivity of tumor cells. However, little is known about how the immunophenotype of the tumor cells is modulated thereby. Therefore, we investigated whether the combination of ATM or ATR inhibitors with hypo-fractionated radiotherapy (RT) has a different impact on the expression of immune checkpoint markers (extrinsic), the release of cytokines or the transcriptome (intrinsic) of head and neck squamous cell carcinoma (HNSCC) cells. The toxic and immunogenic effects of the smKI AZD0156 (ATMi) and VE-822 (ATRi) in combination with a hypo-fractionated scheme of 2x5Gy RT on HPV-negative (HSC4, Cal-33) and HPV-positive (UM-SCC-47, UD-SCC-2) HNSCC cell lines were analyzed as follows: cell death (necrosis, apoptosis; detected by AnxV/PI), expression of immunostimulatory (ICOS-L, OX40-L, TNFSFR9, CD70) and immunosuppressive (PD-L1, PD-L2, HVEM) checkpoint marker using flow cytometry; the release of cytokines using multiplex ELISA and the gene expression of Cal-33 on mRNA level 48h post-RT. Cell death was mainly induced by the combination of RT with both inhibitors, but stronger with ATRi. Further, the immune phenotype of cancer cells, not dying from combination therapy itself, is altered predominantly by RT+ATRi in an immune-stimulatory manner by the up-regulation of ICOS-L. However, the analysis of secreted cytokines after treatment of HNSCC cell lines revealed an ambivalent influence of both inhibitors, as we observed the intensified secretion of IL-6 and IL-8 after RT+ATRi. These findings were confirmed by RNAseq analysis and further the stronger immune-suppressive character of RT+ATMi was enlightened. We detected the down-regulation of a central protein of cytoplasmatic sensing pathways of nucleic acids, RIG-1, and found one immune-suppressive target, EDIL3, strongly up-regulated by RT+ATMi. Independent of a restrictive toxicity, the combination of RT + either ATMi or ATRi leads to comprehensive and immune-modulating alterations in HNSCC. This includes pro-inflammatory signaling induced by RT + ATRi but also anti-inflammatory signals. These findings were confirmed by RNAseq analysis, which further highlighted the immune-suppressive nature of RT + ATMi.

Significant Impact of let-7d MicroRNA on Breast Cancer Cell Lines Post-Radiation Treatment

Introduction: Radiotherapy is a common treatment for breast cancer treatment, that induces DNA damage. These DNA damages are addressed through various repair pathways, which regulate the DNA repair systems and confer radio-resistance. Non-coding RNAs are a big proportion of genome transcripts without the potential to encode proteins. Related studies demonstrated that radiation affects the expression of non-coding RNAs. Let-7d, a tumor suppressor in numerous cancers, has some target genes that play a role in the DNA repair system. Materials and Methods: Human breast cancer cell lines MDA-MB-231 and MCF-7 were cultured in a Dulbecco's Modified Eagle Medium. The exponentially growing cells were treated with some doses of X-rays. After radiation treatment and cell harvesting, RNA was extracted, and cDNA synthesis was done. The let-7d miRNA expression changes were calculated with real-time quantitative reverse transcription polymerase chain reaction. Results: The results implied that radiation caused increased let-7d expression in breast cancer cell lines after radiation treatment. In addition, the results showed that 24 h after radiation, the expression of let-7d in the radioresistant cell line was higher than the radiosensitive one; 48 h after radiation, the expression of let-7d in the radiosensitive cell line was higher than the other one. Conclusions: The results demonstrated that radiation treatment increased let-7d miRNA expression in both radiosensitive and radio-resistant breast cancer cell lines. Therefore, let-7d might be involved in the radiosensitivity of breast cancer.

Targeting MGST1 Makes Non-Small Cell Lung Cancer Cells Sensitive to Radiotherapy by Epigenetically Enhancing ALOX15-Mediated Ferroptosis.

Ferroptosis is closely related to radiotherapy resistance in multiple can-cers. Herein, the role of microsomal glutathione S-transferase 1 (MGST1) in regulating ferropto-sis and radiotherapy resistance in non-small cell lung cancer (NSCLC) was investigated. Radiation-resistant NSCLC cells (NCI-1299-IR and HCC827-IR cells) were estab-lished. After exposure to X-ray, cell proliferation and survival were assessed by colony formation assay and CCK-8 assay, and lipid ROS level was examined by the fluorophore BODIPY™ 581/591 C11. MDA, GSH, and Fe2+ levels were measured by ELISA kits. The molecular interac-tion was analyzed using ChIP and MSP assays. Our results showed that RSL3 treatment greatly enhanced the radiotherapy sensitivity of NCI-1299-IR and HCC827-IR cells. It was subsequently revealed that MGST1 was highly ex-pressed in NCI-1299-IR and HCC827-IR cells than its parent cells, and silencing of MGST1 re-duced radioresistance of NCI-1299-IR and HCC827-IR cells by facilitating ferroptosis. Mechanis-tically, MGST1 knockdown greatly reduced HO-1 and DNMT1/3A protein levels, leading to re-duced DNA methylation on the ALOX15 promoter region, thereby epigenetically upregulating ALOX15 expression. As expected, the promoting effects of MGST1 silencing on radiosensitivity and ferroptosis in radiation-resistant NSCLC cells were strikingly eliminated by ALOX15 knock-down. MGST1 knockdown epigenetically enhanced radiotherapy sensitivity of NCSLC cells by promoting ALOX15-mediated ferroptosis through regulating the HO-1/DNMT1 pathway.

Phosphorylation of BRCA1 at serine 1387 plays a critical role in cathepsin S-mediated radiation resistance via BRCA1 degradation and BCL2 stabilization

There is evidence that BRCA1, particularly cytoplasmic BRCA1, plays a significant role in initiating apoptosis through various mechanisms. Maintaining the stability of BRCA1 in cancer cells may be a promising therapeutic strategy for breast cancer, especially in cases of triple-negative breast cancer (TNBC) lacking appropriate therapeutic targets. Previously, it was reported that cathepsin S (CTSS) interacts with the BRCT domain of BRCA1, leading to ubiquitin-mediated degradation. We further investigated the critical role of BRCA1 phosphorylation at Ser1387, which is mediated by ionizing radiation (IR)-induced activation of ATM. This phosphorylation event was identified as a key factor in CTSS-mediated ubiquitin degradation of BRCA1. The functional inhibition of CTSS, using small molecules or a knockdown system, sensitized TNBC cells when exposed to IR by restoring the stability of cytoplasmic BRCA1. The increase in cytoplasmic BRCA1 led to the degradation of anti-apoptotic BCL2, which was responsible for the radiosensitization effect observed with CTSS inhibition. These results suggest that inhibiting CTSS may be an effective strategy for radiosensitization in TNBC cells through BCL2 degradation that is mediated by inhibition of CTSS-induced BRCA1 degradation.

Discovery of Novel PROTAC SIRT6 Degraders with Potent Efficacy against Hepatocellular Carcinoma.

Sirtuin 6 (SIRT6), a member of the SIRT family, plays essential roles in the regulation of metabolism, inflammation, aging, DNA repair, and cancer development, making it a promising anticancer drug target. Herein, we present our use of proteolysis-targeting chimera (PROTAC) technology to formulate a series of highly potent and selective SIRT6 degraders. One of the degraders, SZU-B6, induced the near-complete degradation of SIRT6 in both SK-HEP-1 and Huh-7 cell lines and more potently inhibited hepatocellular carcinoma (HCC) cell proliferation than the parental inhibitors. In preliminary mechanistic studies, SZU-B6 hampered DNA damage repair, promoting the cellular radiosensitization of cancer cells. Our SIRT6 degrader SZU-B6 displayed promising antitumor activity, particularly when combined with the well-known kinase inhibitor sorafenib or irradiation in an SK-HEP-1 xenograft mouse model. Our results suggest that these PROTACs might constitute a potent therapeutic strategy for HCC.

CD39 inhibitor (POM-1) enhances radiosensitivity of esophageal squamous cell carcinoma (ESCC) cells by promoting apoptosis through the Bax/Bcl-2/Caspase 9/Caspase 3 pathway

CD39 inhibitor (sodium polyoxotungstate, POM-1) has been reported to have antitumor effects. However, the synergistic effect of POM-1 with radiotherapy requires further elucidation. This study aimed to investigate the role and the molecular mechanism of POM-1 in esophageal squamous cell carcinoma (ESCC) radiosensitization. Firstly, the expression of CD39 in ESCC cells and normal esophageal epithelial cells were detected. Then radioresistant ESCC cells (Eca109R and KYSE150R) were constructed and CD39 expression was analyzed. Furthermore, the effect of POM-1 on radiosensitivity for parent cells and radioresistant cells were observed. Then, we analyzed the effect of POM-1 and CD39 siRNA on radiotherapy-induced apoptosis and determined whether POM-1 modulated the radioresistance of ESCC cells depending on the apoptotic signaling pathway. Finally, we validated the synergistic effect of POM-1 combined with radiotherapy in vivo. Our results showed that CD39 was highly expressed in ESCC cells and radioresistant ESCC cells (p < 0.05). POM-1 reduced radioresistance and proliferation of parent cells and radioresistant cells (p < 0.05). Further mechanistic exploration showed that inhibition of CD39 promoted radiation-induced apoptosis (p < 0.05). Bax knockdown reversed the effect of POM-1 on ESCC cells (p < 0.01). Animal experiments also validated that radiotherapy combined with POM-1 enhanced tumor inhibition in vivo (p < 0.05). These results suggested that POM-1 had synergistic effect with radiotherapy by enhancing cell apoptosis through Bax/Bcl-2 signal pathway in ESCC. The combination of POM-1 and radiotherapy is expected to enhance the anti-tumor effect in ESCC.

Regulation of a novel circATP8B4/miR-31-5p/nestin ceRNA crosstalk in proliferation, motility, invasion and radiosensitivity of human glioma cells.

Deregulation of circular RNAs (circRNAs) is frequent in human glioma. Although circRNA ATPase phospholipid transporting 8B4 (circATP8B4) is highly expressed in glioma, its precise action in glioma development is still not fully understood. The relationship of microRNA (miR)-31-5p and circATP8B4 or nestin (NES) was predicted by bioinformatic analysis and confirmed by RNA pull-down and Dual-luciferase reporter assays. CircATP8B4, miR-31-5p and NES were quantified by qRT-PCR or western blot. Cell functional behaviors were assessed by EdU, wound-healing and transwell invasion assays. Xenograft model experiments were performed to define circATP8B4's activity in vivo. CircATP8B4, a true circular transcript, was upregulated in human glioma. CircATP8B4 downregulation weakened glioma cell growth, motility, and invasion and facilitated radiosensitivity. Mechanistically, circATP8B4 and NES 3'UTR harbored a shared miR-31-5p pairing site, and circATP8B4 involved the post-transcriptional NES regulation by functioning as a competing endogenous RNA (ceRNA). Furthermore, the miR-31-5p/NES axis participated in circATP8B4's activity in glioma cell proliferation, motility, invasion and radiosensitivity. Additionally, circATP8B4 loss diminished tumor growth and enhanced the anticancer effect of radiotherapy in vivo. We have uncovered an uncharacterized ceRNA cascade, circATP8B4/miR-31-5p/NES axis, underlying glioma development and radiosensitivity. Targeting the ceRNA crosstalk may have potential to improve the outcome of glioma patients.

Differential biological effect of low doses of ionizing radiation depending on the radiosensitivity in a cell line model

Purpose Exposure to low doses (LD) of ionizing radiation (IR), such as the ones employed in computed tomography (CT) examination, can be associated with cancer risk. However, cancer development could depend on individual radiosensitivity. In the present study, we evaluated the differences in the response to a CT-scan radiation dose of 20 mGy in two lymphoblastoid cell lines with different radiosensitivity. Materials and Methods Several parameters were studied: gene expression, DNA damage, and its repair, as well as cell viability, proliferation, and death. Results were compared with those after a medium dose of 500 mGy. Results After 20 mGy of IR, the radiosensitive (RS) cell line showed an increase in DNA damage, and higher cell proliferation and apoptosis, whereas the radioresistant (RR) cell line was insensitive to this LD. Interestingly, the RR cell line showed a higher expression of an antioxidant gene, which could be used by the cells as a protective mechanism. After a dose of 500 mGy, both cell lines were affected by IR but with significant differences. The RS cells presented an increase in DNA damage and apoptosis, but a decrease in cell proliferation and cell viability, as well as less antioxidant response. Conclusions A differential biological effect was observed between two cell lines with different radiosensitivity, and these differences are especially interesting after a CT scan dose. If this is confirmed by further studies, one could think that individuals with radiosensitivity-related genetic variants may be more vulnerable to long-term effects of IR, potentially increasing cancer risk after LD exposure.

Abstract A011: Enhanced Radiosensitivity of Pancreatic Cancer Achieved through Inhibition of Cyclin-Dependent Kinase 1

Abstract Introduction: One of the major challenges in treating Pancreatic Ductal Adenocarcinoma (PDAC) is overcoming radioresistance. This study investigates the targeting of Cyclin-dependent kinase-1 (CDK1) through both genetic and pharmaceutical inhibition as a strategy to increase the radiosensitivity of PDAC cells. Methods: We conducted mass spectrometry and phosphoproteomics analyses to compare engineered radiation-resistant PDAC cell lines (MIA PaCa-2 and PANC-1) with their parental controls. Additionally, we examined the TCGA PDAC database to correlate clinical outcomes, such as overall survival (OS), with CDK1 mRNA expression levels in PDAC patients. Furthermore, we developed a microRNA-based TET-on inducible shRNA to specifically inhibit CDK1 expression in PDAC cell lines. In an orthotopic PDAC model, we evaluated the radiation sensitivity of PDAC tumors with or without doxycycline treatment. We also employed a selective CDK1 inhibitor, RO-3306, to target CDK1 activation, followed by in vitro experiments using immunoblotting, immunocytochemistry, and clonogenic assays. Results: Our phosphoproteomics analysis revealed a significant increase in phospho-CDK1 (Tyr15) levels in the radiation-resistant cell lines. High CDK1 expression was associated with poorer OS in PDAC patients. Additionally, we observed heightened CDK1 phosphorylation at the threonine tyrosine 14 (Tyr14) residue following radiation exposure. Through our in vivo and in vitro experiments, we demonstrated that CDK1 inhibition, in conjunction with radiation therapy, delayed tumor growth and enhanced radiosensitivity in PDAC cells. Treatment with RO-3306 caused a substantial shift of cells into the G2/M phase and disrupted DNA repair post-radiation exposure, further enhancing radiosensitivity. Conclusion: Our findings underscore the critical role of CDK1 in PDAC radioresistance. Targeting CDK1 in combination with radiotherapy shows promise for future exploration as a potential treatment strategy in PDAC. Citation Format: Stetson Van Matre, Saaimatul Huq, Lokesh Akana, Oscar Zuniga, Henrique Rodrigues, Adam Wolfe. Enhanced Radiosensitivity of Pancreatic Cancer Achieved through Inhibition of Cyclin-Dependent Kinase 1 [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: Advances in Pancreatic Cancer Research; 2024 Sep 15-18; Boston, MA. Philadelphia (PA): AACR; Cancer Res 2024;84(17 Suppl_2):Abstract nr A011.

Complement is increased in treatment resistant rectal cancer and modulates radioresistance

Resistance to neoadjuvant chemoradiation therapy (neo-CRT) is a significant clinical problem in the treatment of locally advanced rectal cancer. Identification of novel therapeutic targets and biomarkers predicting therapeutic response is required to improve patient outcomes. Increasing evidence supports a role for the complement system in resistance to anti-cancer therapy. In this study, increased expression of complement effectors C3 and C5 and increased production of anaphylatoxins, C3a and C5a, was observed in radioresistant rectal cancer cells. Modulation of the central complement effector, C3, was demonstrated to functionally alter the radioresponse, with C3 overexpression significantly enhancing radioresistance, whilst C3 inhibition significantly increased sensitivity to a clinically-relevant dose of radiation. Inhibition of C3 was demonstrated to increase DNA damage and alter cell cycle distribution, mediating a shift towards a radiosensitive cell cycle phenotype suggesting a role for C3 in reprogramming of the tumoural radioresponse. Expression of the complement effectors C3 and C5 was significantly increased in human rectal tumour tissue, as was expression of CFB, a component of the alternative pathway of activation. Elevated levels of C3a and C5b-9 in pre-treatment sera from rectal cancer patients was associated with subsequent poor responses to neo-CRT and poorer survival. Together these data demonstrate a role for complement in the radioresistance of rectal cancer and identify key complement components as potential biomarkers predicting response to neo-CRT and outcome in rectal cancer.

MiR-6855-5p Enhances Radioresistance and Promotes Migration of Pancreatic Cancer by Inducing Epithelial-Mesenchymal Transition via Suppressing FOXA1: Potential of Plasma Exosomal miR-6855-5p as an Indicator of Radiosensitivity in Patients with Pancreatic Cancer.

Whether radiation should be added to neoadjuvant treatment remains controversial, and liquid biopsy has not been reported to predict radioresistance in pancreatic cancer (PC). We aimed to identify microRNAs (miRNAs) governing radioresistance in PC by utilizing peripheral plasma exosome samples and to verify their usefulness as biomarkers. miRNA microarray analysis was conducted using pretreatment peripheral plasma exosomes from 10 patients with PC receiving neoadjuvant chemoradiotherapy (NACRT) in the discovery cohort. Patients were categorized into two groups (good and poor responders) based on treatment responses, and candidate miRNAs exhibiting differential expression between the two groups were identified. The radiosensitivity of PC cells was examined after miR-6855-5p overexpression. Next-generation sequencing (NGS) and TargetScan were used to explore the mechanisms of radioresistance. We investigated the correlation between miR-6855-5p expression levels in the pretreatment peripheral plasma exosomes of 28 patients in the validation cohort and the response to NACRT. miR-6855-5p expression was higher in poor responders than in good responders. miR-6855-5p induces radioresistance in PC cells. NGS showed that epithelial-mesenchymal transition (EMT) was involved in miR-6855-5p-related radioresistance. Forkhead box protein A1 (FOXA1) was identified as a direct target of miR-6855-5p using NGS and TargetScan. Clinical examination of samples from the validation cohort revealed a tendency for patients with higher expression of miR-6855-5p in peripheral plasma exosomes to exhibit increased radioresistance (r=-0.5964). miR-6855-5p regulates the radioresistance of PC by inducing EMT via suppressing FOXA1, and miR-6855-5p in peripheral plasma exosomes may be a biomarker for radioresistance of PC.

Enhanced radiosensitivity of pancreatic cancer achieved through inhibition of Cyclin-dependent kinase 1

Background and purposeOvercoming radioresistance is a critical challenge in pancreatic ductal adenocarcinoma (PDAC). Our study investigates the targeting of Cyclin-dependent kinase-1 (CDK1) through genetic and pharmaceutical inhibition to radiosensitize PDAC cells. Materials and MethodsMass spectrometry and phosphoproteomics were used to analyze engineered radiation-resistant PDAC cell lines (MIA PaCa-2 and PANC-1) compared to parental controls. The TCGA PDAC database was queried for clinical outcomes and patients were dichotomized based on the median CDK1 mRNA expression. We generated a microRNA-based TET-on inducible shRNA to inhibit CDK1 expression in two PDAC cell lines. We used an orthotopic model of PDAC to test the radiation sensitivity of PDAC tumors with or without doxycycline treatment. We targeted CDK1 activation with a selective CDK1 inhibitor, RO-3306, followed by in vitro experiments employing immunoblotting, immunocytochemistry, and clonogenic assays. ResultsPhosphoproteomics analysis revealed that phospho-CDK1 (Tyr15) was significantly elevated in the resistant clones. We found that high CDK1 expression was associated with worse OS in PDAC patients. Radiation exposure increased CDK1 phosphorylation. In MIA PaCa-2 and PANC-1 cells, CDK1 inhibition synergized with radiation therapy to delay tumor growth in vivo. CDK1 inhibition via. RO-3306 resulted in a significant shift of cells into the G2/M phase and disrupted DNA repair after radiation exposure. In vitro, pre-treatment with RO-3306 led to enhanced radiosensitivity of PDAC cells. ConclusionCDK1 plays a crucial role in PDAC radioresistance. Targeting CDK1 with radiotherapy holds promise for further investigation in PDAC treatment.

PRMT1 promotes radiotherapy resistance in glioma stem cells by inhibiting ferroptosis.

The existence of glioma stem cells (GSCs) in cancer is related to glioma radiotherapy resistance. In this research, the effect of protein arginine methyltransferase 1 (PRMT1) on the radiosensitivity of glioma stem cell (GSC)-like cells, as well as its underlying mechanism, was investigated. GSCs-like cells were analyzed and identified by flow cytometry. The self-renewal capability was evaluated by sphere-forming assay. The PRMT1 expression level in glioblastoma were analyzed using the Gene Expression Profiling Interactive Analysis database. The mRNA and protein were scrutinized by RT-qPCR and western blot, respectively. The radiosensitivity was evaluated by clonogenic survival assay. Ferroptosis was evaluated by detecting the levels of reactive oxygen species, malondialdehyde, Fe2+, glutathione, and 4-hydroxynonenal. U87 and SHG44 cells with GSC-like phenotype (GSC-U87 and GSC-SHG44) displayed strong expression of CD133 and nestin versus the glioma cells. GSC-U87 and GSC-SHG44 possess the self-renewal capability. The level of PRMT1 was higher in glioblastoma tumor tissues than in the normal paracancer tissues. Knockdown of PRMT1 enhanced the radiotherapy sensitivity of GSCs-like cells, which wasevidenced by reduced survival fraction in GSC-U87 and GSC-SHG44 underwent sh-PRMT1 transfection. But, this effect was attenuated by Fer-1 (a ferroptosis inhibitor) treatment, accompanied by the abatement of ferroptosis. PRMT1 promoted radiotherapy resistance in GSCs-like cells by inhibiting ferroptosis.

Silencing APLNR enhances the radiosensitivity of prostate cancer by modulating the PI3K/AKT/mTOR signaling pathway.

Aberrant expression of apelin receptor (APLNR) has been found to be involved in various cancers' development, however, its function in prostate cancer (PCa) remains unclear. The research aimed to investigate the role and potential mechanism of APLNR in PCa. The mRNA expression of APLNR was detected via qRT-PCR assay. PCa cell proliferation and apoptosis were determined through plate cloning and flow cytometry. In addition, the expression of apoptosis-related proteins (Bax, Bcl-2, and cleaved caspase-3) was evaluated using western blot. DNA damage marker (γ-H2AX) was analyzed by immunofluorescence and western blot. GSEA analysis was performed for seeking enrichment pathways of APLNR in PCa, and the protein levels of PI3K, p-PI3K, AKT, p-AKT, mTOR, and p-mTOR were tested using western blot. APLNR expression was up-regulated in PCa tissues and cells. Silencing APLNR enhanced the sensitivity of PCa cells to radiotherapy, which was manifested by inhibiting cell proliferation, promoting cell apoptosis, and promoting DNA damage. Next, silencing APLNR inhibited the PI3K/AKT/mTOR pathway. Specifically, 740Y-P (the PI3K/AKT/mTOR pathway activator) reversed the effects of silencing APLNR on PCa cell proliferation, apoptosis and DNA damage. Silencing APLNR inhibited cell proliferation, promoted cell apoptosis, and enhanced the radiosensitivity of PCa cells, which was involved in the PI3K/AKT/mTOR signaling pathway. This study is conducive to the deeper understanding of PCa and further provides a new perspective for the treatment of PCa.

Metformin-loaded chitosan nanoparticles augment silver nanoparticle-induced radiosensitization in breast cancer cells during radiation therapy

Recent research has focused on enhancing tumor response to radiation therapy using radiosensitizers to increase radiation absorption by cancerous tissues. This study utilized silver nanoparticles (AgNPs) as radiation sensitizers and chitosan as a nanocarrier to deliver metformin to breast cancer cells. Metformin-loaded chitosan nanoparticles (Met NPs) and AgNPs were synthesized and characterized. MCF-7 breast cancer cells were pretreated with Met NPs, followed by treatment with AgNPs and irradiation with X-rays at 2, 4, and 8 Gy doses. Cellular cytotoxicity, apoptosis, DNA damage, and 3D spheroid formation were evaluated. The synthesized Met NPs and AgNPs had average diameters of 51.5 ± 9.4 nm and 3.02 ± 0.03 nm, respectively. Cellular cytotoxicity assessment revealed the highest cytotoxicity in MCF-7 cells pretreated with Met NPs, treated with AgNPs, and irradiated with 8 Gy. Flow cytometry analysis demonstrated a 67.58 % apoptosis rate in cells pretreated with Met NPs, compared to 30.42 % in cells pretreated with plain metformin. DAPI staining revealed a 1.8-fold increase in DNA damage in cells pretreated with Met NPs and Ag NPs upon exposure to radiation. The 3D spheroid culture model confirmed a 60 % enhancement in the radiosensitivity of breast cancer cells in the presence of Met NPs and Ag NPs. The combination of Met NPs and Ag NPs represents a promising strategy to improve the therapeutic efficacy of radiation therapy for breast cancer treatment. The delivery of metformin can potentiate the radiosensitizing effects of Ag NPs, offering a novel approach to enhance cancer cells' response to radiation.

Experimental study of radioprotective properties of lithium pyruvate in vitro

Radiotoxicity is a serious problem for patients undergoing radiotherapy, so the search for new radioprotective drugs to mitigate its effects is highly relevant. Radioprotectors should have a number of properties, including direct antioxidant action, reduction of oxidative stress, ability to induce DNA repair or inhibit apoptosis, and at the same time not cause their own side effects. Antioxidants based on lithium salts look promising in terms of their properties. The aim of study was to study the radioprotective properties of lithium pyruvate in vitro. Material and Methods. Relatively radiosensitive blood mononuclear cells and relatively radioresistant fibroblasts of 3T3L1 line were used as biomodels for x-ray exposure. Cells were incubated and irradiated in 96-well plates. Lithium pyruvate was used at a final concentration of 1.2 mM. Cells were irradiated at a dose rate of 15 mGy/s in the absorbed-dose range from 0 to 5 Gy using an x-ray unit (anode voltage: 160 kV, average current: 3.5 mA). Cell viability was assessed by MTT test and resazurin test. The evaluation of cell death variants and the level of oxidative stress were determined by cytofluorimetric method. Results. The cytoprotective effect of lithium pyruvate was established. Cytoprotection was manifested in the increased cell survival and decreased oxidative stress level under lithium pyruvate after x-ray in a wide range of absorbed doses. Relatively high efficiency was shown in relation to blood mononuclear cells with an increase in the viable fraction by 5–7 % and a decrease in oxidative stress level during irradiation in the range of 1.0–3.0 Gy. Apoptosis was found to be the main mechanism of cell death after irradiation. Lithium pyruvate reduced the level of apoptosis in cell population under irradiation and chemically induced oxidative stress. Conclusion. Radioprotective effect of lithium pyruvate under x-ray irradiation in vitro has been shown. Reduction of oxidative stress under the action of pyruvate provides a pathogenetic basis for the potential use of this compound as a radioprotector, which requires further studies on in vivo models.

Dihydroartemisinin enhances the radiosensitivity of breast cancer by targeting ferroptosis signaling pathway through hsa_circ_0001610

ObjectiveThis study aimed to elucidate how DHA enhances the radiosensitivity of BC and to explain its potential mechanisms of action. MethodsThe circular structure of hsa_circ_0001610 was confirmed by Sanger sequencing, RNase R treatment, RT-PCR analysis using gDNA or cDNA. Cellular localization of hsa_circ_0001610 and microRNA-139–5p (miR-139–5p) was detected by fluorescence in situ hybridization. Cell counting kit-8 assay, wound healing and colony formation tests for assessing cell proliferation, while flow cytometry was utilized to estimate cell cycle progression and apoptosis. Reactive oxygen species and malondialdehyde experiments were conducted to validate ferroptosis of BC cells. The expression of ncRNAs and mRNAs was quantified via qRT-PCR, and protein expression was analyzed using Western blot. The effects of hsa_circ_0001610 and DHA on radiosensitivity of BC in vivo were studied by establishing BC mice model. ResultsIn vivo and in vitro experimental results indicate that DHA promotes ferroptosis of BC cells at least partly by inhibiting hsa_circ_0001610/miR-139–5p/SLC7A11 pathway, thereby enhancing the radiosensitivity of BC cells. ConclusionsOur findings showed that DHA can induce ferroptosis of BC cells by down-regulation of hsa_circ_0001610, thus enhancing radiosensitivity, suggesting a promising therapeutic strategy for enhancing BC radiosensitivity that is worthy of further exploration.

NUSAP1 promotes gastric cancer radioresistance by inhibiting ubiquitination of ANXA2 and is suppressed by miR-129-5p

BackgroundRadiotherapy is an important strategy for the treatment of advanced gastric cancer (GC), while the radioresistance limits its effectiveness. Nucleolar and spindle associated protein 1 (NUSAP1) was implicated in cancer progression and chemoresistance. However, the underlying mechanisms of NUSAP1 influencing GC radioresistance remain largely unknown.MethodsMeta-analysis was conducted to systematically evaluate the prognostic value of NUSAP1 in human cancers. Gene set enrichment analysis (GSEA) was conducted using The Cancer Genome Atlas (TCGA) and gene expression omnibus (GEO) datasets. MRNA and protein expressions were detected by qRT-PCR and western blot, respectively. The radiosensitivity of GC cells was observed by colony formation, flow cytometry, comet, immunofluorescence, and animal assays. Immunoprecipitation assay and mass spectrometry were utilized to identify protein associations. MiRNAs binding with NUSAP1 were determined by starbase prediction, luciferase reporter, and RNA immunoprecipitation (RIP) assays.ResultsNUSAP1 high expression predicted worse overall survival (OS) and disease-free survival (DFS) with no statistical heterogeneity through the meta-analysis. Downregulation of NUSAP1 significantly increased GC radiosensitivity by inhibiting colony formation, DNA damage repair, and promoting apoptosis following irradiation. Additionally, NUSAP1 silencing combined with radiation resulted in a synergistic anti-tumor effect in xenograft mouse model. Mechanistically, NUSAP1 interacted with ANXA2, protecting it against protein degradation via impeding its ubiquitination process. NUSAP1 was confirmed as a target of miR-129-5p and negatively regulated by it.ConclusionOur results suggested that NUSAP1 enhanced the radioresistance of GC cells. NUSAP1 could be a promising target to increase GC radiosensitivity.