Identification of oxeiptosis-associated lncRNAs and prognosis-related signature to predict the immune status in gastric cancer

As a novel form of cell death, oxeiptosis is mainly caused by oxidative stress and has been defined to contribute to the cellular death program in cancer. However, the precise involvement of oxeiptosis-related long non-coding RNAs (lncRNAs) within gastric cancer (GC) remains elusive. Thus, our study was aimed to elucidate the pivotal effect of hub oxeiptosis-related lncRNAs on GC by comprehensively analyzing lncRNA and gene expression data obtained from The Cancer Genome Atlas (TCGA) database. Subsequently, we constructed a risk signature (risk-sig) using lncRNAs and further evaluated its prognostic significance. We successfully identified thirteen lncRNAs closely related with oxeiptosis that exhibited significant relevance to the prognosis of GC, forming the foundation of our meticulously constructed risk-sig. Notably, our clinical analyses unveiled a strong correlation between the risk-sig and crucial clinical parameters including overall survival (OS), gender, TNM stage, grade, M stage, and N stage among GC patients. Intriguingly, the diagnostic accuracy of this risk-sig surpassed that of conventional clinicopathological characteristics, underscoring its potential as a highly informative prognostic tool. In-depth mechanistic investigations further illuminated a robust association between this risk-sig and fundamental biological processes such as tumor stemness, immune cell infiltration, and immune subtypes. These findings provide valuable insights into the complex interplay between oxeiptosis-related lncRNAs and the intricate molecular landscape of GC. Ultimately, leveraging the risk scores derived from our comprehensive analysis, we successfully developed a nomogram that enables accurate prediction of GC prognosis. Collectively, our study established a solid foundation for the integration of thirteen hub oxeiptosis-related lncRNAs into a clinically applicable risk-sig, potentially revolutionizing prognostic assessment in GC and facilitating the development of innovative therapeutic strategies.

[KEAP1/PGAM5/AIFM1 mediated oxeiptosis pathway in TDCIPP-induced reduction of TM4 cell viability]

OBJECTIVE

To investigate the toxic effects and potential mechanisms of tri(1, 3-dichloro-2-propyl) phosphate(TDCIPP) exposure on the mouse testicular supporting cell line(TM4 cells).

METHODS

TM4 cells were treated with different concentrations of TDCIPP(0, 12.5, 25 and 50 μmol/L), or 50 μmol/L TDCIPP combined with antioxidant N-acetylcysteine(NAC) for 24 h. Cell viability was assessed using the CCK8 assay, intracellular ROS levels were detected using the DCFH-DA probe, and the protein levels of oxeiptosis-related proteins, such as KEAP1, PGAM5, AIFM1 and phosphorylated AIFM1(p-AIFM1), were detected using Western blot.

RESULTS

TDCIPP dose-dependently reduced TM4 cell viability(P<0.05). ROS levels in TM4 cells treated with 12.5, 25 and 50 μmol/L TDCIPP were 9.44±1.42, 17.25±1.81 and 18.38±2.66, respectively, significantly higher than the control group's 5.08±0.90(P<0.05). ROS levels in the 5 mmol/L NAC+50 μmol/L TDCIPP group were 14.70±0.50, significantly lower than the corresponding TDCIPP group's 26.44±0.73(P<0.05). The activity of TM4 cells in KEAP1siRNA+TDCIPP group and PGAM5siRNA+TDCIPP group were 77.00±1.73 and 76.67±1.53, respectively, significantly higher than TDCIPP group 68.67±1.53(P<0.05). The relative expression of KEAP1 protein in TM4 cells treated with 25 and 50 μmol/L TDCIPP were 0.77±0.04 and 0.82±0.02, respectively, significantly higher than the control group's 0.57±0.01(P<0.05). The relative expression of PGAM5 protein in TDCIPP-treated TM4 cells were 1.17±0.04, 1.38±0.03 and 1.41±0.03, respectively, significantly higher than the control group's 0.81±0.02(P<0.05). The relative expression of AIFM1 protein were 0.42±0.01, 0.63±0.01 and 0.68±0.02, respectively, significantly higher than the control group's 0.34±0.02(P<0.05). The relative expression of p-AIFM1 protein were 1.73±0.02, 1.52±0.02 and 0.73±0.01, respectively, significantly lower than the control group's 2.25±0.02(P<0.05). In the 5 mmol/L NAC+50 μmol/L TDCIPP group, the relative expression of KEAP1, PGAM5 and AIFM1 proteins in TM4 cells were 0.61±0.01, 0.58±0.01 and 0.48±0.03, respectively, significantly lower than the TDCIPP group's 0.86±0.12(P<0.05), 0.74±0.02(P<0.05) and 0.92±0.01(P<0.05). The relative expression of p-AIFM1 protein in the 5 mmol/L NAC+50 μmol/L TDCIPP group was 0.45±0.11, significantly higher than the TDCIPP group's 0.23±0.01(P<0.05).

CONCLUSION

The reduction of TM4 cell viability induced by TDCIPP may be related to ROS-mediated regulation of the KEAP1/PGAM5/AIFM1 pathway, leading to oxeiptosis.

Mitochondria Targeted Nanoparticles Potentiate Tumor Chemo-Phototherapy by Toxic Oxidative Stress Mediated Oxeiptosis

Insufficient accumulation of drug at the tumor site and the low drug response are the main reason for the unsatisfactory effect of cancer therapy. Delivery drugs exquisitely to subcellular level can be employed to reduce side effects, and expand the therapeutic window. Herein, a triphenylphosphine (TPP) modified lipid nanoparticles is designed which are loaded with the photosensitizer indocyanine green (ICG) and chemotherapeutic paclitaxel (PTX) for mitochondria-targeted chemo-phototherapy. Owing to the movement of majority mitochondria along microtubules in cytoplasm, mitochondrial targeting may enable PTX to act more effectively. Meanwhile, the existence of chemo-drug potentiates the phototherapy to achieve synergistic anti-tumor activity. As expected, mitochondria targeting nanomedicine (M-ICG-PTX NPs) showed improved mitochondria targeted cellular distribution and enhanced cell cytotoxicity in vitro. Also, M-ICG-PTX NPs exhibited higher tumor growth inhibition ability by promoting cell apoptosis and oxeiptosis pathway, and high effective inhibition of primary tumor growth and tumor metastasis. Taken together, M-ICG-PTX NPs may be promising nanoplatforms to achieve potent therapeutic effect for the combination of chemo- and photo-therapy (PTT).

Phenethyl isothiocyanate and dasatinib combination synergistically reduces hepatocellular carcinoma growth via cell cycle arrest and oxeiptosis

Introduction: Hepatocellular carcinoma (HCC) is the most common type of liver cancer, which is among the most lethal tumours. Combination therapy exploits multiple drugs to target key pathways synergistically to reduce tumour growth. Isothiocyanates have been shown to possess anticancer potential and to complement the anticancer activity of other compounds. This study aimed to investigate the potential of phenethyl isothiocyanate (PEITC) to synergise with dasatinib, improving its anticancer potential in HCC. Methods: MTT, 3D spheroids and clonogenic assays were used to assess the combination anti-tumour effect in vitro, whereas a murine syngeneic model was employed to evaluate the combination efficacy in vivo. DCFDA staining was employed to evaluate the production of reactive oxygen species (ROS), while flow cytometry and Western blot assays were used to elucidate the molecular mechanism of the synergistic activiy. Results: PEITC and dasatinib combination exhibited a synergistic effect in vitro and in vivo. The combination induced DNA damage and oxidative stress through the production of ROS, which led to the formation of a premature CDK1/Cyclin B1 complex associated with induction of mitotic catastrophe. Furthermore, ROS activated oxeiptosis, a caspase-independent form of programmed cell death. Conclusion: PEITC showed to enhance dasatinib action in treating HCC with increased production of ROS that induced cell cycle arrest followed by mitotic catastrophe, and to induce oxeiptosis. These results highlight the role that ITCs may have in cancer therapy as a complement of clinically approved chemotherapeutic drugs.

Polystyrene nanoplastics induce haematotoxicity with cell oxeiptosis and senescence involved in C57BL/6J mice

Nanoplastics (NPs) has become a worrying serious environmental problem. However, the toxicological effects and mechanisms of NPs on hematopoiesis are still unknown. To this end, male C57BL/6J mice were directly exposed to the serial concentration gradient of polystyrene NPs (PSNPs, 0, 30, 60, and 120 μg d), respectively, for 42 days by intragastric administration. Results show that PSNPs were clearly visible in bone tissues, meanwhile, induced the count of major blood indicators (WBC, RBC, and LYM) decreased. H&E staining displayed that exposed to PSNPs can cause hematopoietic damage of BM and extramedullary hematopoiesis in spleen. Flow cytometry result show that the proportion of LSK represented a dose-dependent significantly decreased after PSNPs exposure. Further research found that PSNPs can cause the systemic oxidative stress occurs manifested as MDA accumulated. In addition, as the dose of PSNPs increased, the fluorescence intensity of Keap1 and p53 in femur sections gradually increased, meanwhile, the expression of cell oxeiptosis signal pathway Keap1/PGAM5/AIFM1 and the cell senescence signal pathway p53/p21 was all increased, markedly. Overall, our study demonstrated that PSNPs exposure caused oxidative stress, potentially resulting in cell oxeiptosis and senescence to develop haematotoxicity in C57BL/6J mice.

Identification and validation of oxeiptosis-associated lncRNAs and prognosis-related signature genes to predict the immune status in uterine corpus endometrial carcinoma

As a novel cell death modality, oxeiptosis is mainly caused by oxidative stress. However, the associations of uterine corpus endometrial carcinoma (UCEC) with oxeiptosis-associated long non-coding RNAs (lncRNAs) are unknown. Here, to identify hub oxeiptosis-associated lncRNAs in UCEC, we collected the data for lncRNAs and gene expression in UCEC from The Cancer Genome Atlas (TCGA) database. Then, a lncRNA risk signature was constructed, and its prognostic value was further evaluated. Finally, the expression levels of hub lncRNA HOXB-AS3 were validated by quantitative RT-PCR analysis. MTT and wounding analyses were also applied to confirm the role of HOXB-AS3 knockdown on UCEC cells. Five lncRNAs associated with oxeiptosis and connected to the prognosis of UCEC were identified, and a risk signature was constructed based on these identified lncRNAs. Our clinical value analyses suggested that the risk signature was closely connected to the overall survival, TNM stage, and grade of UCEC patients. Meanwhile, compared to the conventional clinicopathological characteristics, this risk signature exhibited significantly higher diagnostic accuracy. Moreover, the potential mechanism analysis indicated a close connection of this risk signature to tumor stemness, m6A-related genes, immune cell infiltration, and immune subtypes. Based on the risk scores, we constructed a nomogram. In vitro experiments found that HOXB-AS3 was significantly higher expressed in UCEC cells, and the silence of HOXB-AS3 inhibited the proliferation and migration of UCEC cells. In conclusion, using five hub lncRNAs associated with oxeiptosis, we generated a risk signature, which could be applied in the novel therapeutic strategies of UCEC development.

Mitoquinone shifts energy metabolism to reduce ROS-induced oxeiptosis in female granulosa cells and mouse oocytes

The female reproductive system is quite sensitive to regulation, and external environmental stimuli may cause oxidative stress which in turn may lead to accelerated aging and programmed cell death in female reproductive cells. The aim of this study was to investigate whether or not mitoquinone (MitoQ) could resist ROS-induced apoptosis in human granulosa cells and mouse oocytes. We found that the MitoQ treatment significantly reduced production of reactive oxygen species (ROS) and imbalance in mitochondrial membrane potential. The MitoQ treatment prevented an excessive mitochondrial fragmentation by upregulating Drp1 S637 and decreasing Drp1 S637 phosphorylation. More importantly, MitoQ maintained aerobic respiration and reduced anaerobic respiration by regulating reprogramming of intracellular energy metabolism, which enhanced cellular ATP production. MitoQ effectively reduced the expressions of AIFM1 and PGAM5, key molecules whose expressions were reversed not only in granulosa cells but also in mouse oocytes. Our findings suggest that MitoQ can ameliorate the mitochondrial deterioration caused by ROS and reprogram cellular energy metabolism, providing protection to cells against apoptosis. The presence of MitoQ may help in protecting human germ cells under in vitro culture conditions.