Sensitivity Of Cells Research Articles

Targeting mTOR and survivin concurrently potentiates radiation therapy in renal cell carcinoma by suppressing DNA damage repair and amplifying mitotic catastrophe

BackgroundRenal cell carcinoma (RCC) was historically considered to be less responsive to radiation therapy (RT) compared to other cancer indications. However, advancements in precision high-dose radiation delivery through single-fraction and multi-fraction stereotactic ablative radiotherapy (SABR) have led to better outcomes and reduced treatment-related toxicities, sparking renewed interest in using RT to treat RCC. Moreover, numerous studies have revealed that certain therapeutic agents including chemotherapies can increase the sensitivity of tumors to RT, leading to a growing interest in combining these treatments. Here, we developed a rational combination of two radiosensitizers in a tumor-targeted liposomal formulation for augmenting RT in RCC. The objective of this study is to assess the efficacy of a tumor-targeted liposomal formulation combining the mTOR inhibitor everolimus (E) with the survivin inhibitor YM155 (Y) in enhancing the sensitivity of RCC tumors to radiation.Experimental designWe slightly modified our previously published tumor-targeted liposomal formulation to develop a rational combination of E and Y in a single liposomal formulation (EY-L) and assessed its efficacy in RCC cell lines in vitro and in RCC tumors in vivo. We further investigated how well EY-L sensitizes RCC cell lines and tumors toward radiation and explored the underlying mechanism of radiosensitization.ResultsEY-L outperformed the corresponding single drug-loaded formulations E-L and Y-L in terms of containing primary tumor growth and improving survival in an immunocompetent syngeneic mouse model of RCC. EY-L also exhibited significantly higher sensitization of RCC cells towards radiation in vitro than E-L and Y-L. Additionally, EY-L sensitized RCC tumors towards radiation therapy in xenograft and murine RCC models. EY-L mediated induction of mitotic catastrophe via downregulation of multiple cell cycle checkpoints and DNA damage repair pathways could be responsible for the augmentation of radiation therapy.ConclusionTaken together, our study demonstrated the efficacy of a strategic combination therapy in sensitizing RCC to radiation therapy via inhibition of DNA damage repair and a substantial increase in mitotic catastrophe. This combination therapy may find its use in the augmentation of radiation therapy during the treatment of RCC patients.

ARID1A loss promotes RNA editing of CDK13 in an ADAR1-dependent manner

BackgroundARID1A, a subunit of the SWI/SNF chromatin remodeling complex, is thought to play a significant role both in tumor suppression and tumor initiation, which is highly dependent upon context. Previous studies have suggested that ARID1A deficiency may contribute to cancer development. The specific mechanisms of whether ARID1A loss affects tumorigenesis by RNA editing remain unclear. ResultsOur findings indicate that the deficiency of ARID1A leads to an increase in RNA editing levels and alterations in RNA editing categories mediated by adenosine deaminases acting on RNA 1 (ADAR1). ADAR1 edits the CDK13 gene at two previously unidentified sites, namely Q113R and K117R. Given the crucial role of CDK13 as a cyclin-dependent kinase, we further observed that ADAR1 deficiency results in changes in the cell cycle. Importantly, the sensitivity of ARID1A-deficient tumor cells to SR-4835, a CDK12/CDK13 inhibitor, suggests a promising therapeutic approach for individuals with ARID1A-mutant tumors. Knockdown of ADAR1 restored the sensitivity of ARID1A deficient cells to SR-4835 treatment.ConclusionsARID1A deficiency promotes RNA editing of CDK13 by regulating ADAR1.

Deficient gap junction coupling of two common hearing loss-related variants in GJB2.

To explore the functional consequences of two common variants, p.V37I and c.299-300delAT in hearing loss associated gene GJB2. Connexin 26 expression and gap junctional permeability were studied in HEK 293T cells transfected with plasmids expressing GJB2 wild-type, p.V37I, or c.299-300delAT CX26 proteins with fluorescent tags. Functional analyses of different GJB2 haplotypes were performed to fully assess the alteration of ionic and small-molecule coupling. The p.V37I protein was localized at the plasma membrane, but failed to effectively transport intercellular propidium iodide or Ca2+ efficiently, indicating impairment of both biochemical and ionic coupling. The presence of GJB2 p.V37I appeared to increase the sensitivity of cells to H2O2 treatment. In contrast, the known variant c.299-300delAT protein was not transported to the cell membrane and could not form gap junctions, instead being confined to the cytoplasm. Ionic and biochemical coupling was defective in c.299-300delAT-transfected cells. The p.V37I and c.299-300delAT GJB2 mutations resulted in deficient gap junction-mediated coupling. Environmental factors may impact the functional consequences of GJB2 p.V37I. These results may inspire the development of molecular therapies targeting GJB2 mutations for hearing loss.

GLUT1 promotes cell proliferation via binds and stabilizes phosphorylated EGFR in lung adenocarcinoma

BackgroundWhile previous studies have primarily focused on Glucose transporter type 1 (GLUT1) related glucose metabolism signaling, we aim to discover if GLUT1 promotes tumor progression through a non-metabolic pathway.MethodsThe RNA-seq and microarray data were comprehensively analyzed to evaluate the significance of GLUT1 expression in lung adenocarcinoma (LUAD). The cell proliferation, colony formation, invasion, and migration were used to test GLUT1 ‘s oncogenic function. Co-immunoprecipitation and mass spectrum (MS) were used to uncover potential GLUT1 interacting proteins. RNA-seq, DIA-MS, western blot, and qRT-PCR to probe the change of gene and cell signaling pathways.ResultsWe found that GLUT1 is highly expressed in LUAD, and higher expression is related to poor patient survival. GLUT1 knockdown caused a decrease in cell proliferation, colony formation, migration, invasion, and induced apoptosis in LUAD cells. Mechanistically, GLUT1 directly interacted with phosphor-epidermal growth factor receptor (p-EGFR) and prevented EGFR protein degradation via ubiquitin-mediated proteolysis. The GLUT1 inhibitor WZB117 can increase the sensitivity of LUAD cells to EGFR-tyrosine kinase inhibitors (TKIs) Gefitinib.ConclusionsGLUT1 expression is higher in LUAD and plays an oncogenic role in lung cancer progression. Combining GLUT1 inhibitors and EGFR-TKIs could be a potential therapeutic option for LUAD treatment.

Progress in the study of autophagy-related proteins affecting resistance to chemotherapeutic drugs in leukemia.

Leukemia is a life-threatening malignant tumor of the hematopoietic system. Currently, the main treatment modalities are chemotherapy and hematopoietic stem cell transplantation. However, increased drug resistance due to decreased sensitivity of leukemia cells to chemotherapeutic drugs presents a major challenge in current treatments. Autophagy-associated proteins involved in autophagy initiation have now been shown to be involved in the development of various types of leukemia cells and are associated with drug resistance. Therefore, this review will explore the roles of autophagy-related proteins involved in four key autophagic processes: induction of autophagy and phagophore formation, phagophore extension, and autophagosome formation, on the development of various types of leukemias as well as drug resistance. Autophagy may become a promising therapeutic target for treating leukemia.

Highly conductive coated wires for interconnection of solar cells with TECC-wire technology

TECC-Wire (thermoplastic and electrically conductive coated wire) represents a promising interconnection technology for temperature sensitive solar cells. TECC-Wire uses round copper wires (160–300 μm) coated with a thermoplastic polymer layer (10–20 μm), filled with electrically conductive particles. This study presents a new wire coating formulation based on a polyamide-type wire enamel (Voltatex® 8609 ECO, melting temperature 180 °C), filled with 12 vol% silver resulting in a conductivity of 480 S/cm. Single half-cut M6 heterojunction (SHJ) solar cells were contacted with the manufactured wires using a laboratory scale stringing machine. Peel tests were performed to characterize the adhesion of the wires to the cell surface, module performance was evaluated using electroluminescence (EL) imaging and current-voltage (IV) measurements, damp heat (DH) tests were used to evaluate the long-term stability of the modules. The wires adhere well to the cells with a peel force of more than 1.5 N/mm, and the highly conductive coating has proven to be robust when contacted with different pressure, which might be beneficial for a reliable high throughput solar module production. The obtained fill factor FF = 81.25 ± 0,12 % is similar to those achieved for solar modules connected via standard soldering techniques IEC standard DH tests confirmed that, the modules exhibiting a power loss of less than 5 % after 1000 h of storage at +85 °C and 85 % relative humidity. These results are very encouraging for further development of the technology towards a low temperature, solder-free, low cost and robust cell interconnection technology.

Saturated fatty acid concentrations are predictive of insulin sensitivity and beta cell compensation in dogs

Chronic feeding of a high fat diet (HFD) in preclinical species induces broad metabolic dysfunction characterized by body weight gain, hyperinsulinemia, dyslipidemia and impaired insulin sensitivity. The plasma lipidome is not well characterized in dogs with HFD-induced metabolic dysfunction. We therefore aimed to describe the alterations that occur in the plasma lipid composition of dogs that are fed a HFD and examine the association of these changes with the clinical signs of metabolic dysfunction. Dogs were fed a normal diet (ND) or HFD for 12 weeks. Insulin sensitivity (SI) and beta cell compensation (AIRG) were assessed through an intravenous glucose tolerance test (IVGTT) and serum biochemistry was analyzed before the introduction of HFD and again after 12 weeks of continued ND or HFD feeding. Plasma lipidomics were conducted prior to the introduction of HFD and again at week 8 in both ND and HFD-fed dogs. 12 weeks of HFD feeding resulted in impaired insulin sensitivity and increased beta cell compensation measured by SI (ND mean: 11.5 [mU/l]–1 min–1, HFD mean: 4.7 [mU/l]–1 min–1) and AIRG (ND mean: 167.0 [mU/l]min, HFD mean: 260.2 [mU/l]min), respectively, compared to dogs fed ND over the same duration. Chronic HFD feeding increased concentrations of plasma lipid species and deleterious fatty acids compared to dogs fed a ND. Saturated fatty acid (SFA) concentrations were significantly associated with fasting insulin (R2 = 0.29), SI (R2 = 0.49) and AIRG (R2 = 0.37) in all dogs after 12 weeks, irrespective of diet. Our results demonstrate that chronic HFD feeding leads to significant changes in plasma lipid composition and fatty acid concentrations associated with metabolic dysfunction. High SFA concentrations may be predictive of deteriorated insulin sensitivity in dogs.

Ferroptosis is involved in cisplatin sensitivity of the S3 segment of immortalized proximal tubule cells

Cisplatin (CDDP) is administered as an anticancer drug across a broad spectrum of cancer treatments, but it causes severe renal damage. Several studies have attempted to elucidate the cause of CDDP-induced renal injury, but the detailed mechanism remains unclear. We previously found that S3 cells are more sensitive to CDDP than S1 and S2 cells by using immortalized cells derived from S1, S2, and S3 segments of proximal tubules. In this study, we investigated the potential contribution of reactive oxygen species (ROS) to the sensitivity of S3 cells to CDDP. The results showed that S3 cells have high sensitivity to CDDP, paraquat (PQ) and three ROS substances. To examine the mechanisms underlying the sensitivity to ROS in S3 cells, we compared the cellular responses of CDDP- and PQ-exposed S3 cells. The results indicated that the levels of intracellular ROS and lipid peroxides were increased in S3 cells after CDDP and PQ exposure. The intracellular levels of antioxidant proteins such as thioredoxin, thioredoxin reductase 1 and glutathione peroxidase 4 were also increased by exposure to PQ, but these proteins were decreased by CDDP exposure in S3 cells. Furthermore, the levels of intracellular free Fe2+ were increased by CDDP exposure only in S3 cells but not S1 or S2 cells, and cytotoxicity by exposure to CDDP in S3 cells was suppressed by ferroptosis inhibitors. These results suggested that the induction of ferroptosis due to the ROS production through attenuation of the antioxidant system and elevated free Fe2+ is partly responsible for the sensitivity of S3 cells to CDDP.

Silencing PCMT1 enhances the sensitivity of breast cancer cells to paclitaxel through the PI3K/Akt/STMN1 pathway.

This study aimed to investigate whether silencing Protein L-isoaspartate (D-aspartate) O-methyltransferase (PCMT1) expression can enhance the sensitivity of breast cancer cells to paclitaxel and its possible mechanism. Tumor tissues and adjacent histologically normal tissues were collected from patients with breast cancer admitted to our hospital. Human normal breast epithelial cells MCF10A, human breast cancer cells MCF-7, and paclitaxel-resistant breast cancer cells MCF-7/PR were purchased. MCF-7/PR cells were further grouped into negative control (NC) group, si-PCMT1 group (transfected with si-PCMT1), 740Y-P group (treated with 740Y-P, an activator of phosphatidylinositol 3-kinase (PI3K)/ v-Akt Murine Thymoma Viral Oncogene (AKT) signaling pathway), and si-PCMT1 + 740Y-P group (transfected with si-PCMT1 and then treated with 740Y-P). The expression level of PCMT1 in tissues and cells was detected by quantitative real-time polymerase chain reaction (qRT-PCR). Western blot analysis was used to detect the protein expression level of PCMT1 in tissues and cells as well as the protein level of p-PI3K, PI3K, p-Akt, Akt, and Stathmin1 (STMN1) in cells. 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-di-phenytetrazoliumromide (MTT) and colony formation assays were used to determine cell viability, scratch assay was used to assess the migration ability of cells, and Transwell assay was used to assess the invasion ability of cells. The expression of PCMT1 was remarkably up-regulated in breast cancer tissues and MCF-7/PR cells. Silencing PCMT1 expression significantly inhibited the proliferation, migration, and invasion of MCF-7/PR cells, and alleviated the resistance of cancer cells to paclitaxel. Additionally, silencing PCMT1 expression also inhibited the activation of PI3K/Akt/STMN1 pathway in MCF-7/PR cells, while activating PI3K/Akt/STMN1 pathway significantly reversed the effect of silencing PCMT1 expression on MCF-7/PR cells. PCMT1 is highly expressed in breast cancer tissues and MCF-7/PR cells, and silencing PCMT1 expression can not only inhibit the development of breast cancer but also enhance paclitaxel sensitivity. Its mechanism of action may be achieved by inhibiting PI3K/Akt/STMN1 signaling.

Modulation of the HIF-1α-NCOA4-FTH1 Signaling Axis Regulating Ferroptosis-induced Hepatic Stellate Cell Senescence to Explore the Anti-hepatic Fibrosis Mechanism of Curcumol.

Senescence of activated hepatic stellate cells (HSC) reduces extracellular matrix expression to reverse liver fibrosis. Ferroptosis is closely related to cellular senescence, but its regulatory mechanisms need to be further investigated. The iron ions weakly bound to ferritin in the cell are called labile iron pool (LIP), and together with ferritin, they maintain cellular iron homeostasis and regulate the cell's sensitivity to ferroptosis. We used lipopolysaccharide (LPS) to construct a pathological model group and divided the hepatic stellate cells into a blank group, a model group, and a curcumol 12.5 mg/L group, a curcumol 25 mg/L group, and a curcumol 50 mg/L group. HIF-1α-NCOA4- FTH1 signalling axis, ferroptosis and cellular senescence were detected by various cellular molecular biology experiments. We found that curcumol could induce hepatic stellate cell senescence by promoting iron death in hepatic stellate cells. Curcumol induced massive deposition of iron ions in hepatic stellate cells by activating the HIF-1α-NCOA4-FTH1 signalling axis, which further led to iron overload and lipid peroxidation-induced ferroptosis. Interestingly, our knockdown of HIF-1α rescued curcumol-induced LIP and iron deposition in hepatic stellate cells, suggesting that HIF-1α is a key target of curcumol in regulating iron metabolism and ferroptosis. We were able to rescue curcumol-induced hepatic stellate cell senescence when we reduced LIP and iron ion deposition using iron chelators. Overall, curcumol induces ferroptosis and cellular senescence by increasing HIF-1α expression and increasing NCOA4 interaction with FTH1, leading to massive deposition of LIP and iron ions, which may be the molecular biological mechanism of its anti-liver fibrosis.

Exosomal miR-19a derived from melanoma cell promotes the vemurafenib resistance of malignant melanoma through directly targeting LRIG1 to reactivate AKT and MAPK pathway

Exosomal miR-19a derived from melanoma cell promotes the vemurafenib resistance of malignant melanoma through directly targeting LRIG1 to reactivate AKT and MAPK pathway

Mitochondrial dysfunction significantly contributes to the sensitivity of tumor cells to anoikis and their metastatic potential

It is well-known that the survival of metastatic cells during their dissemination plays an important role in metastasis. However, does this mean that the final result of the metastatic cascade (the volume of metastatic damage to distant organs and tissues) depends on, or at least correlates with, the degree of resistance to anoikis (distinctive hallmarks of metastatic cells)? This question remains open.The aim of the work was to study in vitro the changes in the survival rates, proliferative activity, oxidative stress, and glycolysis intensity during three days of anchorage-dependent and anchorage-independent growth of two Lewis lung carcinoma cell lines (LLC and LLC/R9) and compare these changes with the status of mitochondria and metastatic potential of the cells in vivo. MethodsThe number and volume of lung metastases were estimated for each cell line after intramuscular inoculation of the cells in C57Bl/6 mice. For the in vitro study, the cells were seeded on Petri dishes pretreated with poly-HEMA or untreated dishes and then allowed to grow for 3 days. Cell viability, cell cycle progression, the level of reactive oxygen species (ROS), glucose consumption and lactate production rates were investigated daily in both growth conditions. An electron microscopy study of intracellular structures was carried out. ResultsThe study showed (as far as we know for the first time) a correlation between the metastatic potential of cells (determined in vivo) and their sensitivity to anoikis (assessed in vitro). The transition of LLC/R9 cells with an inherently defective mitochondrial system to the conditions of anchorage-independent growth was characterized by a decrease in survival, a slowdown in growth rates, an increase in both glucose consumption rate and intracellular ROS levels and manyfold lower metastatic potential, compared to highly metastatic LLC cells with the normal mitochondrial system.

Clinicopathological characteristics and survival in metastatic colorectal cancer with short-form APC mutations.

3555 Background: Wnt/β-catenin signaling is activated by loss-of-function mutations in the adenomatous polyposis coli ( APC) gene and plays a key role in tumorigenesis in colorectal cancer (CRC). Tankyrase inhibitors, which cause degradation of β-catenin, are expected to have a promising therapeutic effect for CRC, and the short-form APC mutations predict the sensitivity of CRC cells to tankyrase inhibitors (Tanaka et al. Mol Cancer Ther 2017; Chen et al. Br J Cancer, in press).However, clinicopathological characteristics and survival in metastatic CRC (mCRC) with short-form APCmutations remain unclear. Methods: Patients with mCRC who were treated with chemotherapy between 2010 and 2021 and have tissue or circulating tumor DNA-based next-generation sequencing results were enrolled. Short-form APC mutations were defined as those truncated at amino acid 1,256 or shorter, lacking all seven 20-amino acid repeat (20-AAR) regions. Non-short-form APC mutations were defined as those possess more than one 20-AAR. Short-form and non-short-form heterozygous mutations were classified as non-short-form APC mutations. We confirmed incidence of mCRC with short-form APC mutations and compared clinicopathological characteristics and overall survival (OS) between mCRC patients with short-form and non-short-form APCmutations. Results: Of 177 patients (median age, 56.0 years) included in this study, 44 (25%) and 79 (45%) had short-form and non-short-form APC mutations, respectively. Patients with short-form APC mutations were not likely to have lung metastasis (P = 0.15). Logistic regression multivariate analysis, lung metastasis was related to mCRC patients with short-form APC mutations (Odds ratio: 0.46, P = 0.047). Patients with short-form APC mutations had significantly shorter overall survival (OS) than did those without (n = 133), with a median OS of 34.7 vs 50.5 months ( P Log-rank= 0.035, hazard ratio (HR), 1.59; 95% confidence interval (CI), 1.03-2.45). In multivariate analysis, short-form APC mutation was independent factor related to OS (hazard ratio (HR): 1.68, P = 0.02), as well as the BRAF V600E mutation, liver metastasis and peritoneal metastasis. Conclusions: Short-form APC mutation is more common in mCRC patients without lung metastases and is independently associated with a short prognosis.

Performance evaluation of ruthenium complexes and organic sensitizers in ZnO-based dye-sensitized solar cells

Ruthenium (Ru) dyes are a well-known player in the field of dye-sensitized solar cells (DSSCs) due to their high efficiency and excellent stability. Their properties and complexes have been studied for almost three decades. Although these sensitizers show better performances, their high cost makes these third-generation solar devices less economical. Organic dyes have recently been explored as an alternative to Ru-based dyes due to their easy and low-cost synthesis. A comparative performance evaluation of Ru complexes and dicyanoisophorone and rhodanine organic dyes in ZnO-based DSSCs is here reported. All the Ru complexes showed better performance in comparison to organic dyes except R-4. Among the Ru sensitizers, R-3 exhibited the highest efficiency of 1.21% followed by R-2, which is attributed to the presence of several anchoring groups such as carboxyl, nitro and amine. However, the presence of more nitrogen-based groups has drastically reduced the performance as observed for R-4, which is the least performing dye among the Ru-based ones. On the contrary, organic sensitizers S-06 and P-4 revealed to be less efficient with respect to R-3 owing to the presence of only one anchoring group and weak photoanode/dye interaction.

IQGAP1 overexpression attenuates chemosensitivity through YAP-mediated ferroptosis inhibition in esophageal squamous cell cancer cells

Chemoresistance is one of the major hindrances to many cancer therapies, including esophageal squamous cell carcinoma (ESCC). Ferroptosis, a new programmed cell death, plays an essential role in chemoresistance. IQ-domain GTPase activating protein 1 (IQGAP1) is a scaffold protein and functions as an oncogene in various human malignancies. However, the underlying effect and molecular mechanisms of IQGAP1 on paclitaxel (PTX) resistance and ferroptosis in ESCC remain to be elucidated. In this study, we found that IQGAP1 was highly expressed in ESCC tissues and could as a potential biomarker for diagnosis and predicting the prognosis of ESCC. Functional studies revealed that IQGAP1 overexpression reduced the sensitivity of ESCC cells to PTX by enhancing ESCC cell viability and proliferation and inhibiting cell death, and protected ESCC cells from ferroptosis, whereas IQGAP1 knockdown exhibited contrary effects. Importantly, reductions of chemosensitivity and ferroptosis caused by IQGAP1 overexpression were reversed with ferroptosis inducer RSL3, while the increases of chemosensitivity and ferroptosis caused by IQGAP1 knockdown were reversed with ferroptosis inhibitor ferrostatin-1 (Fer-1) in ESCC cells, indicating that IQGAP1 played a key role in resistance to PTX through regulating ferroptosis. Mechanistically, we demonstrated that IQGAP1 overexpression upregulated the expression of Yes-associated protein (YAP), the central mediator of the Hippo pathway. YAP inhibitor Verteporfin (VP) could reverse the effects of IQGAP1 overexpression on ESCC chemoresistance and ferroptosis. Taken together, our findings suggest that IQGAP1 promotes chemoresistance by blocking ferroptosis through targeting YAP. IQGAP1 may be a novel therapeutic target for overcoming chemoresistance in ESCC.

Immune suppressive drugs negatively regulate the CD8+T cells function by acetyltransferase p300 induced canonical and non-canonical autophagy

Macroautophagy, the mainly regulated form of autophagy, maintains the cellular homeostasis and degrades the transported cargoes. It is initiated by the protein kinase complex regulating by two signals pathway Mammalian target of rapamycin complex1(mTORC1)-Adenosine 5‘ monophosphate activated protein kinase(AMPK)-Unc51 like kinase 1(ULK1) and ULK1-PI3K- phosphatidylinositol 3-phosphate(PI3P). Currently, autolysosomes are accumulated during the aging process of CD8+T cells in vitro and may participate in inducing death sensitization of senescent cells. The main mechanism of aplastic anemia, a hyperimmune disease, is the T cells subsets imbalance such as CD8+T cells abnormal activation and hyperfunction. Therefore, the role of autophagy in the CD8+T cells and supposed whether some immunosuppress drugs induced the cells autophagic death to treat the hyperimmune diseases were focused. It was decided found that the acetyltransferase p300 obviously increased in the aplastic anemia patients and was related with the severity of disease. Previous studies have reported that canonical autophagy is regulated by the mTORC1-p300 axis. p300 is a critical bridge in the p300-VPS34 axis mediated non-canonical autophagy. There is the deficiency of autophagy and acetylation in the CD8+T cells. The expression of p300 also decreased notably after the immunosuppressive drugs therapy. Our findings provide a framework for understanding how immunosuppressive drugs effect on the AA autophagy deficiency mechanism and proved that immunosuppressive drugs negatively regulated the function of CD8+T cells by p300-mediated canonical autophagy pathway and non-canonical autophagy pathway.

Changes in stresses sensitivity of ohmic heating-induced sublethally injured Staphylococcus aureus during repair: Potential mechanisms at the cellular and molecular levels

Changes in stresses sensitivity of ohmic heating-induced sublethally injured Staphylococcus aureus during repair: Potential mechanisms at the cellular and molecular levels

DYNLL1 accelerates cell cycle via ILF2/CDK4 axis to promote hepatocellular carcinoma development and palbociclib sensitivity.

Disorder of cell cycle represents as a major driver of hepatocarcinogenesis and constitutes an attractive therapeutic target. However, identifying key genes that respond to cell cycle-dependent treatments still facing critical challenges in hepatocellular carcinoma (HCC). Increasing evidence indicates that dynein light chain 1 (DYNLL1) is closely related to cell cycle progression and plays a critical role in tumorigenesis. In this study, we explored the role of DYNLL1 in the regulation of cell cycle progression in HCC. We analysed clinical specimens to assess the expression and predictive value of DYNLL1 in HCC. The oncogenic role of DYNLL1 was determined by gain or loss-of-function experiments in vitro, and xenograft tumour, liver orthotopic, and DEN/CCl4-induced mouse models in vivo. Mass spectrometry analysis, RNA sequencing, co-immunoprecipitation assays, and forward and reverse experiments were performed to clarify the mechanism by which DYNLL1 activates the interleukin-2 enhancer-binding factor 2 (ILF2)/CDK4 signalling axis. Finally, the sensitivity of HCC cells to palbociclib and sorafenib was assessed by apoptosis, cell counting kit-8, and colony formation assays in vitro, and xenograft tumour models and liver orthotopic models in vivo. DYNLL1 was significantly higher in HCC tissues than that in normal liver tissues and closely related to the clinicopathological features and prognosis of patients with HCC. Importantly, DYNLL1 was identified as a novel hepatocarcinogenesis gene from both in vitro and in vivo evidence. Mechanistically, DYNLL1 could interact with ILF2 and facilitate the expression of ILF2, then ILF2 could interact with CDK4 mRNA and delay its degradation, which in turn activates downstream G1/S cell cycle target genes CDK4. Furthermore, palbociclib, a selective CDK4/6 inhibitor, represents as a promising therapeutic strategy for DYNLL1-overexpressed HCC, alone or particularly in combination with sorafenib. Our work uncovers a novel function of DYNLL1 in orchestrating cell cycle to promote HCC development and suggests a potential synergy of CDK4/6 inhibitor and sorafenib for the treatment of HCC patients, especially those with increased DYNLL1.

ZNF384 transcriptionally activated MGST1 to confer TMZ resistance of glioma cells by negatively regulating ferroptosis.

Drug resistance is one of the major reasons of the poor prognosis and recurs frequently in glioma. Ferroptosis is considered to be a new therapeutic strategy for glioma. Microsomal glutathione S-transferase 1 (MGST1) expression in glioma samples was ensured through GAPIA database, qRT-PCR, western blotting assay and immunohistochemistry. The interaction between zinc finger protein 384 (ZNF384) and MGST1 promoter was analyzed through UCSC and JASPAR databases and further verified by ChIP and luciferase reporter assay. Cell viability and IC50 value of temozolomide (TMZ) was measured by CCK-8 assay. The production of MDA, GSH and ROS and the level of Fe2+ were determined using the corresponding kit. MGST1 expression was increased in clinical glioma tissues and glioma cells. MGST1 expression was increased but ferroptosis was suppressed in TMZ-resistant cells when contrasted to parent cells. MGST1 silencing downregulated IC50 value of TMZ and cell viability but facilitated ferroptosis in TMZ-resistant cells and parent glioma cells. Moreover, our data indicated that ZNF384 interacted with MGST1 promoter and facilitated MGST1 expression. ZNF384 was also increased expression in TMZ-resistant cells, and showed a positive correlation with MGST1 expression in clinical level.ZNF384 decreasing enhanced the sensitivity of resistant cells to TMZ, while the effect of ZNF384 could be reversed by overexpression of MGST1. MGST1 transcription is regulated by transcription factor ZNF384 in TMZ-resistant cells. ZNF384 confers the resistance of glioma cells to TMZ through inhibition of ferroptosis by positively regulating MGST1 expression. The current study may provide some new understand to the mechanism of TMZ resistance in glioma.

AURKA blockage as a strategy to overcome resistance to olaparib and platinum in high-grade ovarian cancer (HGOC).

e15198 Background: PARP inhibitors (PARPi) as olaparib (OLA) have become the new standard in maintenance treatment in high grade ovarian carcinoma (HGOC). Thus, there is an important need to identify the mechanisms for PARPi resistance and the strategies to overcome them. Our aim is to assess if in vitro inhibition of AURKA, a protein that plays a relevant role in centrosome spindle formation and mitotic regulation, might overcome olaparib resistance mechanisms in HGOC. Methods: Three HGOC cell lines (PEO1, Kuramochi and SKOV3) were selected, and isogenic resistant pairs generated in vitro, by pulsed exposure to OLA (PEO1-R) or by exposure to growing concentrations of OLA (Kuramochi-R and SKOV-R). AURKA expression was assessed by PCR and Western blot (WB). Cells were OLA-treated before and after the downregulation of AURKA expression by a specific small inhibitor RNA (siRNA) and by pharmacologic inhibition with alisertib. Cell viability was assessed by MTT assay and DNA damage by the evaluation of markers by WB. Combination index of the combo OLA+alisertib was assessed by Chou-Talalay method. Results: AURKA expression was lower at gene and protein levels in resistant cell lines compared to parental. Upon AURKA silencing (Si) of parental (OLA-sensitive) cell lines, no differences in the OLA IC50 values between AURKA-Si and control cells were seen. However AURKA-Si of the OLA-resistant cell lines was associated with a decreased in OLA IC50 as follows: 1) In PEO1R control scramble siRNA (sc) was 226 mM vs SI 128 mM, p < 0.0001; 2) In Kuramochi-R scRNA 268.4 mM vs si 130.2 mM p < 0.0001 and 3) in SKOV3-R scRNA 187 mM vs si 74.7 mM, p < 0.0001 suggesting a role of AURKA-si in overcoming OLA-resistance. Pharmacologic AURKA targeting with the inhibitor alisertib in all 3 sensitive and resistant cell lines showed an increase of DNA damage measured by the expression of H2AX protein by WB. Combination index of the OLA+alisertib in all resistant cell lines showed a synergistic effect of the combination with PEO1-R FA50 = 0.25 (FA25-75 0.2-0.31), Kuramochi-R FA50 = 0.29 (0.19-9.36) and SKOV3-R FA50 = 0.24 (0.19-0.36). Conclusions: AURKA targeting either by silencing or pharmacologic inhibition increased OLA-induced apoptosis or had a synergistic effect in OLA-resistant cell lines suggesting AURKA as a potential target for overcoming OLA resistance.