Radioresistant Cells Research Articles

Non-coding RNAs modulation in breast cancer radioresponse: mechanisms and therapeutic implications.

Breast cancer is the most frequent type of cancer in women, with significant incidence and fatality rates. Radiation therapy is an important therapeutic option for breast cancer patients. However, tumor cells' resistance to radiation can limit therapy efficacy, resulting in recurrence and death. Non-coding RNAs (ncRNAs) are aclass of small RNA molecules that do not translate into proteins but can affect the translation of target mRNA. Several investigations on breast cancer have demonstrated abnormal expression of ncRNAs in response to radiation. Non-coding RNAs are essential in controlling numerous processes such as DNA damage response, cancer stem cell pathways, cell cycle regulation, cell death, and inflammation. Dysregulation of ncRNAs after irradiation influences radiosensitivity or radioresistance of breast cancer cells. Understanding the molecular mechanisms underlying Radiation response can lead to innovative treatment ways to reduce breast cancer radioresistance and increase radiotherapy's efficacy. This review summarizes current research on ncRNA dysregulation following irradiation and analyzes ncRNAs' function and mechanism in modifying breast cancer cell radiosensitivity and radioresistance.

Abstract B012: HNRNPL-mediated mRNA stability underlies metastasis triggered by resistance to radiation therapy

Abstract The high rate of locoregional/distant recurrence in triple-negative breast cancer (TNBC) is a major driver of the decreased survival observed in breast cancer patients. Radiation therapy is a reliable treatment modality to limit recurrence for many cancers, but TNBC patients have a higher chance for relapse despite receiving increased doses of radiation compared to patients with other breast cancer subtypes. This study investigated the differential pathways in radioresistant TNBC tumors that impact recurrence. We developed two radioresistant cell line models (468-RR and 4T1-RR) by administering a radiation dose of 50Gy over the course of 8 weeks to the human TNBC cell line, MDA-MB-468, and the mouse TNBC cell line, 4T1, respectively. Migration and invasion were assessed using the scratch-wound assay and transwell assay, respectively. We assessed in vivo metastasis by injecting the cells in the mammary fat pad, tail vein, or left ventricle. RNA-sequencing of the cell lines was done to identify global transcriptomic changes and regulatory pathways induced by radiation therapy. The mRNA stability of integrin b3 was assessed by inhibiting transcription using actinomycin D. Moreover, we implemented the newly developed InduroRT-mediated circRNA-sequencing (IMRT-seq) to identify the circular RNAs processed by HNRNPL that are present in radioresistant cells. We observed enhanced lung and bone metastasis, based on bioluminescent imaging, in both the spontaneous and vascular metastasis models for the radioresistant cells compared to the parental cells. Genset enrichment analysis identified mRNA stability and metabolism as upregulated pathways in radioresistant cells with HNRNPL, a ribonucleoprotein involved in mRNA stability, as one of the top genes. By knocking down HNRNPL, we observed decreased migration capacity of the radioresistant cells. Given the role of HNRNPL in integrin and extracellular matrix genes, which are key components associated with metastasis in cancer cells, we screened for these genes in our RNA-seq dataset and identified integrin b3 as a possible target. More specifically, knocking down HNRNPL decreased the mRNA stability of integrin b3 as assessed by actinomycin d treatment. By expressing integrin b3 in the HNRNPL-depleted cells, we were able to rescue the migration capacity of these cells. We believe a subset of HNRNPL-mediated circular RNAs are responsible for integrin b3 mRNA stability by sequestering miRNAs that target integrin b3. With IMRT-seq we are exploring the potential circRNA-miRNA interactions present in radioresistant TNBC responsible for its metastatic phenotype. The radioresistant cells derived from TNBC cell lines have an enhanced metastatic potential than the treatment-naive cell lines and our data suggest that RNA metabolism is pivotal to this phenotype. The upregulation of HNRNPL upon radiation by Nrf2 increases integrin b3 expression by stabilizing its transcripts and preventing its degradation. This novel mechanism of radioresistant metastasis provides a therapeutic approach to minimize TNBC recurrence. Citation Format: Ayush Kumar, Kensei Kishimoto, Christi Wisniewski, Shivam Goel, Arthur Mercurio. HNRNPL-mediated mRNA stability underlies metastasis triggered by resistance to radiation therapy [abstract]. In: Proceedings of the AACR Special Conference in Cancer Research: RNAs as Drivers, Targets, and Therapeutics in Cancer; 2024 Nov 14-17; Bellevue, Washington. Philadelphia (PA): AACR; Mol Cancer Ther 2024;23(11_Suppl):Abstract nr B012.

Cationic Metal-Organic Layer Delivers siRNAs to Overcome Radioresistance and Potentiate Cancer Radiotherapy.

Radiotherapy plays an important role in modern oncology, but its treatment efficacy is limited by the radioresistance of tumor cells. As a member of the inhibitor of apoptosis protein family, survivin plays a key role in developing radioresistance by mediating apoptosis evasion, promoting epithelial-mesenchymal transition, and modulating cell cycle dynamics. Efficient downregulation of survivin expression presents a promising strategy to enhance the antitumor effects of radiotherapy. Herein, we report the design of a hafnium-porphyrin-based cationic metal-organic layer (CMOL) with quaternary ammonium capping groups to deliver small interfering RNAs (siRNAs) for enhanced radiotherapy. The CMOL@siRNA nanoplatform not only increased energy deposition from X-rays and reactive oxygen species generation via a unique radiotherapy-radiodynamic therapy process, but also effectively delivered siRNAs to downregulate survivin expression and ameliorate radioresistance of cancer cells. Consequently, CMOL@siRNA in combination with low-dose X-ray irradiation demonstrated remarkable antitumor efficacy with 96.9% and 91.4% tumor growth inhibition in murine colorectal carcinoma and triple-negative breast cancer models, respectively.

Cationic Metal‐Organic Layer Delivers siRNAs to Overcome Radioresistance and Potentiate Cancer Radiotherapy

Radiotherapy plays an important role in modern oncology, but its treatment efficacy is limited by the radioresistance of tumor cells. As a member of the inhibitor of apoptosis protein family, survivin plays a key role in developing radioresistance by mediating apoptosis evasion, promoting epithelial‐mesenchymal transition, and modulating cell cycle dynamics. Efficient downregulation of survivin expression presents a promising strategy to enhance the antitumor effects of radiotherapy. Herein, we report the design of a hafnium‐porphyrin‐based cationic metal‐organic layer (CMOL) with quaternary ammonium capping groups to deliver small interfering RNAs (siRNAs) for enhanced radiotherapy. The CMOL@siRNA nanoplatform not only increased energy deposition from X‐rays and reactive oxygen species generation via a unique radiotherapy‐radiodynamic therapy process, but also effectively delivered siRNAs to downregulate survivin expression and ameliorate radioresistance of cancer cells. Consequently, CMOL@siRNA in combination with low‐dose X‐ray irradiation demonstrated remarkable antitumor efficacy with 96.9% and 91.4% tumor growth inhibition in murine colorectal carcinoma and triple‐negative breast cancer models, respectively.

Establishment of acquired radioresistant cells to fractionated radiation from hTERT-immortalized normal human epithelial cell.

Senescence-like growth arrest (SLGA), which is a radiation-induced cell death pathway, is induced in immortalized normal human epithelial cell (hTERT-RPE1) by the daily fractionated X-irradiation with 1.5Gy within 30 times. We here demonstrate that pre-treatment induces acquired radioresistance (ARR) that can survive from the lethal fractionated radiation. The parent cells were daily fractionated with 1.5Gy for 5d and then incubated for 7d without fractionated radiation. After this, the daily fractionated radiation with 1.5Gy was restarted. A small population of surviving cells appeared after 30 times of the daily fractionated radiation was completed and they were continuously growing up to 120 times of the daily fractionated radiation (RPE1-1.5Fr). We confirmed a higher basal expression level of p53, which functions in the activation of the SLGA pathway but fails to further accumulate after 1.5Gy of single irradiation in RPE1-1.5Fr. It is the first report to induce ARR phenotype for fractionated radiation in normal human cells.

TMET-07. RADIORESISTANT GLIOBLASTOMA EVADES MITOCHONDRIAL LIPOTOXICITY THROUGH ALTERED DGKB AND DGAT1

Abstract Glioblastoma (GBM) is the most common and aggressive primary brain tumor, with a median survival of only 15 months despite multimodal therapy. Radiotherapy is a conventional therapy of GBM treatment, but the development of radioresistance often leads to tumor recurrence and treatment failure. To elucidate the molecular mechanisms underlying radioresistance in GBM, we established radioresistant GBM cell lines through repeated exposure to ionizing radiation. Transcriptomic analysis revealed that diacylglycerol kinase beta (DGKB), an enzyme that converts diacylglycerol (DAG) to phosphatidic acid, was significantly downregulated in radioresistant GBM cells. Functional studies demonstrated that knockdown of DGKB or expression of a kinase-dead DGKB mutant resulted in DAG accumulation and reduced fatty acid oxidation. Conversely, overexpression of DGKB activated fatty acid oxidation, increased reactive oxygen species (ROS) production, and sensitized GBM cells to radiation. Interestingly, we found that radiation upregulated the expression of diacylglycerol acyltransferase 1 (DGAT1), which catalyzes the conversion of DAG to triglycerides. Knockdown of DGAT1 using shRNA or miR-3918 mimic reduced lipid droplet formation and enhanced radiosensitivity both in vitro and in vivo. Furthermore, using Connectivity Map, we identified cladribine as a potential radiosensitizing agent that increases DGKB and decreases DGAT1. Cladribine effectively sensitized GBM cells to radiation and significantly prolonged the survival of mice bearing GBM xenografts. In conclusion, our study reveals a novel mechanism by which radioresistant GBM cells maintain lipid homeostasis through downregulation of DGKB and upregulation of DGAT1 to evade lethal mitochondrial lipotoxicity. Targeting the DGKB-DGAT1 axis represents a promising therapeutic strategy to overcome radioresistance and improve the outcomes of GBM patients.

TMET-06. CLIP3 DOWNREGULATION LEADS TO RADIORESISTANCE IN GLIOBLASTOMA BY PROMOTING GLYCOLYTIC FLUX

Abstract Glioblastoma Multiforme (GBM), a highly aggressive primary brain tumor, often develops resistance to standard treatments such as ionizing radiation (IR), which leads to a median survival of about 15 months. GBM contains glioblastoma stem cells (GSCs), which are crucial in driving therapeutic resistance and recurrence. In our study, we conducted comprehensive analyses to evaluate the molecular changes associated with radioresistance and explored the role of the Spy1-CLIP3 axis as a key regulator of GSC maintenance. Our methods included quantitative PCR and immunoblotting to measure CLIP3 mRNA and protein levels, revealing a significant reduction in expression among radioresistant GBM cells. We found that exposure to IR leads to the upregulation of Spy1 and downregulation of CLIP3, contributing to the development of radioresistance in surviving GBM cells. We used metabolic flux analysis techniques to observe changes in glycolytic activity, which increased in correlation with CLIP3 downregulation. IR induces CLIP3 downregulation, increasing glycolytic activity by facilitating the trafficking of GLUT3, the primary glucose transporter in GSCs. Additionally, colony-forming ability was evaluated using colony-forming assay after treatment of glimepiride with or without IR. Glimepiride didn’t reduce colony-forming ability in non-irradiated cells, but when combined with IR, it significantly reduced colony-forming ability, possibly by disrupting maintenance of GSCs. Importantly, our data reveal that glimepiride, a CLIP3 activator targets GSCs metabolism and enhances radiosensitization while maintaining low toxicity. The radioresistant GBM cells that survive radiotherapy exhibit increased stemness and glycolytic activity mediated by the Spy1-CLIP3 axis. Overall, our findings suggest that clinical trials using glimepiride for GBM patients may potentially improve survival rates, particularly for those experiencing recurrence after radiotherapy. This research highlights the importance of targeting cellular metabolism and stem cell properties in the context of GBM radioresistance and suggests potential avenues for improving the effectiveness of existing treatments.

TMET-08. RADIATION-INDUCED SLC25A22 CONTRIBUTES TO GLIOBLASTOMA RADIORESISTANCE ACQUISITION THROUGH REMODELING GLUTAMATE METABOLISM

Abstract Glioblastoma Multiforme (GBM), a malignant primary brain tumor, is treated by surgical resection followed by chemo- and radiotherapy. Nevertheless, most GBM patients show dismal prognosis due to the radioresistance acquisition of GBM cells via metabolic rewiring. Therefore, it is urgently required to discover how metabolic rewiring attributes to GBM radioresistance, and its targeting strategies. To identify GBM radioresistance driver genes, we previously established radioresistance GBM cells (RGCs) via repetitive in vivo selection, followed by mRNA sequencing, and selected candidate genes that are altered in RGCs (fold change>2 or <0.5, p-value<0.05) and also related with GBM patients’ prognosis. Here, we focused on amino acid transmembrane transporter (Gene Ontology: 0003333) and found that SLC25A22 was the most increased in RGCs. SLC25A22 exhibits uni-directional properties, exporting glutamate to cytosol, resulting in cytosolic glutamate accumulation in RGCs. Using 13C glutamine isotope tracing analysis following mitochondrial fractionation, we quantified the mitochondrial metabolic flux of glutamine. Despite decreased 13C glutamate efflux from RGCs mitochondria after genetic inhibition of SLC25A22, glutamine metabolites (a-ketoglutarate, succinate, malate, fumarate) remained constant. Cytosolic glutamate, as a substrate, is incorporated into various biosynthetic pathways, especially glutathione (GSH) and proline synthesis pathways in radioresistant GBM cells. GSH protects GBM cells by scavenging radiation-induced reactive oxygen species. Whereas, proline, a rate-limiting substrate for collagen biosynthesis, leads GBM cells to show an invasiveness phenotype via extracellular matrix remodeling. Genetic inhibition of SLC25A22 using short hairpin RNA (shRNA) or microRNA-184 mimic suppresses RGCs radioresistance and aggressiveness. Additionally, intranasal administration of microRNA-184 mimic prolonged the survival (median survival: 26 days after irradiation) of GBM-bearing mice, compared with non-target control (median survival: 16 days after irradiation). Together, our study demonstrates that SLC25A22 upregulation confers GBM radioresistance by inducing cytosolic glutamate-driven biosynthesis and suggests SLC25A22 as a therapeutic target to overcome GBM radioresistance.

Implication of CCNG1 in radiosensitivity via the Wnt/β-catenin pathway in esophageal squamous cells

Esophageal cancer (EC) poses a substantial threat to human health. The development of radioresistance in esophageal cancer cells is a critical factor contributing to local treatment failure and an unfavorable prognosis in affected patients. A comprehensive analysis was performed using bulk RNA sequencing (RNA-seq) and single-cell RNA sequencing (scRNA-seq) data from esophageal squamous cell carcinoma (ESCC) samples. Radioresistant ESCC cell lines were generated to explore the functional role of CCNG1. Various techniques, including gene knockdown, flow cytometry, and apoptosis assays, were utilized to evaluate alterations in radiosensitivity, cell cycle progression, and cell survival in response to CCNG1 modulation. Elevated CCNG1 expression was associated with poor clinical outcomes in ESCC patients and contributed to various malignant phenotypes in ESCC cells. In radioresistant ESCC cell lines, CCNG1 knockdown markedly increased radiosensitivity, as demonstrated by enhanced G2/M phase arrest and apoptosis following radiation exposure. CellChat analysis indicated a correlation between CCNG1 and the Wnt/β-catenin signaling pathway, while western blot (WB) analysis confirmed that CCNG1 functions as a downstream effector of Wnt/β-catenin. Our study has identified CCNG1 as a key regulator of radiosensitivity in ESCC, mediated through its interaction with the Wnt/β-catenin signaling pathway. Targeting the Wnt/β-catenin/CCNG1 axis presents a promising therapeutic strategy to enhance the efficacy of radiotherapy in ESCC, potentially overcoming radioresistance and improving patient outcomes.

Atomoxetine suppresses radioresistance in glioblastoma via circATIC/miR-520d-5p/Notch2-Hey1 axis

BackgroundResistance acquired after radiotherapy is directly related to the failure of various cancer treatments, including GBM. Because the mechanism for overcoming radioresistance has not yet been clearly identified, the development of diagnostic and therapeutic markers to treat radioresistance is necessary. Since increased expression of stemness- and EMT-related markers are reported to be closely correlated with radioresistance, research is underway to develop new drugs targeting these factors.MethodsTo develop an anticancer drug that overcomes radioresistance, a library of drugs already approved by the FDA was used. After treating radioresistant GBM cells with each drug, the expression of stemness- and EMT-related markers was confirmed by qRT-PCR, and as a result, Atomoxetine (ATX) was selected. It was confirmed that radioresistance-induced cell migratory, invasive, sphere formation abilities, and tumor growth using a xenograft mouse model were suppressed upon ATX treatment. Using a miRNA prediction tool, we discovered miR-520d-5p, which targets Notch2 and Hey1, key factors in radioresistance, and discovered circATIC targeting this miRNA, revealing its relationship with ATX. We demonstrated the expression regulation mechanism and signaling mechanism between circATIC, miR-520d-5p, Notch2, and Hey1 factors using a luciferase reporter assay. In addition, the results at the cellular level were clinically verified by confirming the correlation between radiation, miR-520d-5p, and circATIC using patient plasma by qRT-PCR.ResultsATX showed potential as a treatment for radioresistance by suppressing the malignant phenotype by regulating the circATIC/miR-520d-5p/Notch2-Hey1 signaling mechanism in vitro and in vivo using radioresistant GBM cells.ConclusionsThis study revealed that ATX suppresses radioresistance through the circATIC/miR-520d-5p/Notch2-Hey1 signaling pathway. These results showed the potential of ATX as a new drug that can overcome radioresistance, a major challenge in cancer treatment, and the signaling factors identified in this mechanism suggest the possibility of use as potential targets for the diagnosis and treatment of radioresistance.

Diterpenoid from Croton tonkinensis as a Potential Radiation Sensitizer in Oral Squamous Cell Carcinoma: An In Vitro Study.

Radiotherapy combined with a radiosensitizer represents an important treatment for head and neck squamous cell carcinoma (HNSCC). Only a few chemotherapy agents are currently approved as radiosensitizers for targeted therapy. Oral squamous cell carcinoma is one of the deadliest cancers, with approximately ~500,000 new diagnosed cases and 145,000 deaths worldwide per year. The incidence of new cases continues to increase in developing countries. This study aimed to investigate the effect of Croton tonkinensis and Curcuma longa on cell viability in OSCC cells. The HNSCC cell line OML1 and its radiation-resistant clone OML1-R were used. The anticancer effect and the mechanism of action of Croton tonkinensis and Curcuma longa in OSCC cells were analyzed by using cell viability assays, Western blot analysis, and Tranwell migration assays. The results showed that Croton tonkinensis concentration-dependently reduced the viability of OML1 and OML1-R (radioresistant) cells by downregulating the levels of AKT/mTOR mediators, such as p110α, p85, pAKT (ser473), p-mTOR (ser2448), and p-S6 Ribosomal (ser235/236). We found that cotreatment of OML1 and OML1R cells with either zVAD-FMK (apoptosis inhibitor), Ferrostatin-1 (Fer-1, a ferroptosis inhibitor), or chloroquine (CQ, an autophagy inhibitor) markedly reduced cell death. These results demonstrate that Croton tonkinensis exhibits anti-proliferation activity and highlight the therapeutic potential of small-molecule inhibitors against PI3K/mTOR signaling for radiosensitization in HNC treatment.

A metabolic switch to the pentose-phosphate pathway induces radiation resistance in pancreatic cancer

PurposePancreatic ductal adenocarcinoma (PDAC) is remarkably resistant to standard modalities, including radiotherapy. We hypothesized that metabolic reprogramming may underlie PDAC radioresistance, and moreover, that it would be possible to exploit these metabolic changes for therapeutic intent. Methods and materialsWe established two matched models of radioresistant PDAC cells by exposing the AsPC-1 and MIAPaCa-2 human pancreatic cancer cells to incremental doses of radiation. The metabolic profile of parental and radioresistant cells was investigated using Nanostring technology, labeled-glucose tracing by liquid chromatography-mass spectrometry, Seahorse analysis and exposure to metabolic inhibitors. The synergistic effect of radiation combined with a pentose-phosphate pathway inhibitor, 6-aminonicotinamide (6-AN) was evaluated in a xenograft model established by subcutaneous injection of radioresistant-AsPC-1 cells into nude mice. ResultsThe radioresistant cells overexpressed pyruvate dehydrogenase kinase (PDK) and consistently, displayed increased glycolysis and downregulated the tricarboxylic acid (TCA) cycle and oxidative phosphorylation. Metabolic flux through the pentose-phosphate pathway (PPP) was increased, as were levels of reduced glutathione; pharmacological inhibition of the PPP dramatically potentiated radiation-induced cell death. Furthermore, the combined treatment of radiation with the PPP inhibitor 6-AN synergistically inhibited tumor growth in-vivo. ConclusionsWe provide a mechanistic understanding of the metabolic changes that underlie radioresistance in PDAC. Furthermore, we demonstrate that pancreatic cancer cells can be re-sensitized to radiation via metabolic manipulation, in particular, inhibition of the PPP. Exploitation of the metabolic vulnerabilities of radioresistant pancreatic cancer cells constitutes a new approach to pancreatic cancer, with a potential to improve clinical outcomes.

Downregulation of CTRP1 Reduces Radio-resistance in Glioblastoma Cells by Inhibiting the Expression of CD133 after X-ray and Carbon Ion Irradiation

Glioblastomas (GBMs), the most prevalent primary malignant brain tumors, present significant challenges due to their invasive nature, high recurrence rates, and limited treatment options. Radiotherapy is a cornerstone in the management of GBMs; however, resistance to treatment poses a substantial obstacle. This study investigates the role of adipokine C1q/TNF-related protein 1 (CTRP1) in the radio-sensitivity of GBMs, utilizing both X-ray and carbon ion irradiation. Expression analyses revealed elevated CTRP1 and CD133 levels in GBMs tissues, which were associated with poor patient survival. Carbon ion irradiation demonstrated superior growth inhibition compared to X-ray, particularly in U87 (high CD133) cells. Moreover, CTRP1 expression increased following radiation exposure, especially after X-ray treatment. Knockdown of CTRP1 enhanced radio-sensitivity by reducing cell proliferation and increasing apoptosis, while exacerbating oxidative stress. Bioinformatics analysis revealed CTRP1's involvement in DNA damage repair pathways. Our findings establish a novel connection between CTRP1 and cellular radio-sensitivity. Targeting CTRP1, especially in U87 (high CD133) cells, enhances GBMs radio-sensitivity, offering potential therapeutic avenues.

MiR-1226-5p is involved in radioresistance of colorectal cancer by activating M2 macrophages through suppressing IRF1

BackgroundAlthough the representative treatment for colorectal cancer (CRC) is radiotherapy, cancer cells survive due to inherent radioresistance or resistance acquired after radiation treatment, accelerating tumor malignancy and causing local recurrence and metastasis. However, the detailed mechanisms of malignancy induced after radiotherapy are not well understood. To develop more effective and improved radiotherapy and diagnostic methods, it is necessary to clearly identify the mechanisms of radioresistance and discover related biomarkers.MethodsTo analyze the expression pattern of miRNAs in radioresistant CRC, sequence analysis was performed in radioresistant HCT116 cells using Gene Expression Omnibus, and then miR-1226-5p, which had the highest expression in resistant cells compared to parental cells, was selected. To confirm the effect of miR-1226-5 on tumorigenicity, Western blot, qRT-PCR, transwell migration, and invasion assays were performed to confirm the expression of EMT factors, cell mobility and invasiveness. Additionally, the tumorigenic ability of miR-1226-5p was confirmed in organoids derived from colorectal cancer patients. In CRC cells, IRF1, a target gene of miR-1226-5p, and circSLC43A1, which acts as a sponge for miR-1226-5p, were discovered and the mechanism was analyzed by confirming the tumorigenic phenotype. To analyze the effect of tumor-derived miR-1226-5p on macrophages, the expression of M2 marker in co-cultured cells and CRC patient tissues were confirmed by qRT-PCR and immunohistochemical (IHC) staining analyses.ResultsThis study found that overexpressed miR-1226-5p in radioresistant CRC dramatically promoted epithelial-mesenchymal transition (EMT), migration, invasion, and tumor growth by suppressing the expression of its target gene, IRF1. Additionally, we discovered circSLC43A1, a factor that acts as a sponge for miR-1226-5p and suppresses its expression, and verified that EMT, migration, invasion, and tumor growth are suppressed by circSLC43A1 in radioresistant CRC cells. Resistant CRC cells-derived miR-1226-5p was transferred to macrophages and contributed to tumorigenicity by inducing M2 polarization and secretion of TGF-β.ConclusionsThis study showed that the circSLC43A1/miR-1226-5p/IRF1 axis is involved in radioresistance and cancer aggressiveness in CRC. It was suggested that the discovered signaling factors could be used as potential biomarkers for diagnosis and treatment of radioresistant CRC.

FOS-Mediated PLCB1 Induces Radioresistance and Weakens the Antitumor Effects of CD8+ T Cells in Triple-Negative Breast Cancer.

Radioresistance and immune evasion are interactive and crucial events leading to treatment failure and progression of human malignancies. This research studies the role of phospholipase C beta 1 (PLCB1) in these events in triple-negative breast cancer (TNBC) and the regulatory mechanism. PLCB1 was bioinformatically predicted as a dysregulated gene potentially linked to radioresistance in TNBC. Parental TNBC cell lines were exposed to fractionated radiation for 6 weeks. PLCB1 expression was decreased in the first 2 weeks but gradually increased from Week 3. PLCB1 knockdown increased the radiosensitivity of the cells, as manifested by a decreased half-inhibitory dose of irradiation, reduced cell proliferation, apoptosis resistance, mobility, and tumorigenesis in mice. The FOS transcription factor promoted PLCB1 transcription and activated the PI3K/AKT signaling. Knockdown of FOS similarly reduced radioresistance and T cells-mediated immune evasion. However, the radiosensitivity of TNBC cells and the antitumor effects of CD8+ T cells could be affected by a PI3K/AKT activator or by the PLCB1 upregulation. The PLCB1 or FOS knockdown also suppressed radioresistance and tumorigenesis of the TNBC cells in mice. In conclusion, FOS-mediated PLCB1 induces radioresistance and weakens the antitumor effects of CD8+ T cells in TNBC by activating the PI3K/AKT signaling pathway.

Advantages of single high-dose radiation therapy compared with conventional fractionated radiation therapy in overcoming radioresistance

Background Radioresistance is a major clinical challenge in cancer treatment, as it reduces the effectiveness of radiation therapy (RT). While advances in radiation delivery have enabled the clinical use of high-dose hypofractionated RT, its impact on radioresistant tumors remains unclear. This study aimed to compare the effects of single high-dose RT with conventional fractionated RT on radioresistant breast cancer cells and explore the underlying mechanisms. Methods Radioresistant cell lines were previously established by exposing SK-BR-3 and MCF-7 cells to 48 Gy and 70 Gy of radiation, respectively, in multiple fractions. We compared the effects of 2 Gy × 5 and 7 Gy × 1 fractions on these cells using clonogenic survival assays and western blot analysis. In vivo antitumor effects were assessed in SR tumor-bearing BALB/c mice irradiated with either 2 Gy × 5 or 7 Gy × 1 fractions. Results 7 Gy x1 was more efficient at killing radioresistant breast cancer cells than 2 Gy x5. Furthermore, the 7 Gy x1 fraction produced higher levels of reactive oxygen species (ROS) and decreased the expression of radioresistance factors such as p-STAT3, ACSL4, FOXM1, RAD51, Bcl-xL, and survivin. Consistent with the in vitro studies, the 7 Gy × 1 fraction also showed superior antitumor effects in SR tumor-bearing BALB/c mice. Conclusions Single high-dose RT offers superior advantages over conventional fractionated RT in regard to overcoming radioresistance, supporting its potential as a promising treatment for recurrent tumors.

Role and mechanism of KIAA1429 in regulating cellular ferroptosis and radioresistance in colorectal cancer.

Colorectal cancer (CRC) is one of the most common non-cutaneous malignancies, causing significant mortality and a substantial burden. This study aims to explore the role of KIAA1429 (also known as vir-like m6A methyltransferase associated [VIRMA]) protein in the radioresistance of CRC. CRC cells and a radioresistant cell line were cultured, and KIAA1429 expression was detected. After the down-regulation of KIAA1429, its effect on the radioresistance and ferroptosis of cancer cells was analyzed. The role of ferroptosis in radioresistance was verified. The binding relationship among long non-coding RNA endogenous Bornavirus-like nucleoprotein 3, pseudogene (lncRNA EBLN3P), microRNA (miR)-153-3p, and KIAA1429 was analyzed. KIAA1429 and lncRNA EBLN3P were highly expressed in CRC, while miR-153-3p was poorly expressed. KIAA1429 and lncRNA EBLN3P were further increased/decreased in the radioresistant cells. KIAA1429 knockdown decreased the survival rate of the radioresistant cell line after X-ray irradiation and increased gamma H2A histone family member X (γ-H2AX), ferroptosis, and oxidative stress. A ferroptosis inhibitor alleviated the inhibitory effect of KIAA1429 knockdown on radioresistance. KIAA1429-mediated m6A modification up-regulated lncRNA EBLN3P, and lncRNA EBLN3P increased KIAA1429 by competitively binding to miR-153-3p. miR-153-3p silencing or lncRNA EBLN3P overexpression attenuated the promotion of ferroptosis and the inhibition of radioresistance induced by KIAA1429 knockdown. Overall, KIAA1429-mediated m6A modification up-regulated lncRNA EBLN3P expression, and lncRNA EBLN3P increased KIAA1429 expression by competitively binding to miR-153-3p, thus reducing ferroptosis and increasing the radioresistance of CRC.

Enhancing radiotherapy for melanoma: the promise of high-Z metal nanoparticles in radiosensitization.

Melanoma is a type of skin cancer that can be challenging to treat, especially in advanced stages. Radiotherapy is one of the main treatment modalities for melanoma, but its efficacy can be limited due to the radioresistance of melanoma cells. Recently, there has been growing interest in using high-Z metal nanoparticles (NPs) to enhance the effectiveness of radiotherapy for melanoma. This review provides an overview of the current state of radiotherapy for melanoma and discusses the physical and biological mechanisms of radiosensitization through high-Z metal NPs. Additionally, it summarizes the latest research on using high-Z metal NPs to sensitize melanoma cells to radiation, both in vitro and in vivo. By examining the available evidence, this review aims to shed light on the potential of high-Z metal NPs in improving radiotherapy outcomes for patients with melanoma.

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.

Aldo-keto reductase family 1 member C3 mediates radioresistance of esophageal cancer cells through suppressing MAPK and AKT signaling

BackgroundAldo-keto reductase family 1 member C3 (AKR1C3) is a radioresistance gene in esophageal cancer. This study aimed to investigate the signaling pathways that mediate the regulatory role of AKR1C3 in the radioresistance of esophageal cancer cells.MethodsThe protein levels of AKR1C3 in cancer tissue samples were compared between patients with radiosensitive and radioresistant esophageal cancer using immunohistochemical staining. AKR1C3-silenced stable KYSE170R esophageal cancer cells (KY170R-shAKR1C3) were established. Colony formation assay was employed to evaluate the radiosensitivity of cancer cells, while flow cytometry analysis was utilized to quantify reactive oxygen species (ROS) production in these cells. Additionally, Western blotting was conducted to determine protein expression levels.ResultsAKR1C3 protein exhibited significantly higher expression in radioresistant cancer tissue samples compared to radiosensitive samples. AKR1C3 silencing promoted radiosensitivity and ROS production of KYSE170R cells. At 32 h after X-ray radiation, the levels of total and phosphorylated ERK1/2, JNK, and AKT proteins were significantly elevated in KYSE170R-shAKR1C3 cells compared to untransfected KYSE170R cells. The inhibitor of AKR1C3 remarkably enhanced the radiosensitivity of KYSE170R cells. Conversely, treatment with either a MEK inhibitor or an AKT inhibitor significantly increased the radioresistance of KYSE170R-shAKR1C3 cells.ConclusionsOur results suggest that AKR1C3 mediates radioresistance of KYSE170R cells possibly through MAPK and AKT signaling.