RNAi-mediated IARS2 knockdown inhibits proliferation and promotes apoptosis in human melanoma A375 cells

Unveiling novel targets in melanoma under melanogenesis stimulation and photodynamic therapy by redox proteomics

Melanogenesis-stimulated B16-F10 cells enter in a quiescent state, present inhibited mitochondrial respiration and increased reactive oxygen species levels. These alterations suggest that these cells may be under redox signaling, allowing tumor survival. The aim of this study was to evaluate redox-modified proteins in B16-F10 cells after melanogenesis stimulation and rose bengal-photodynamic therapy (RB-PDT). A redox proteomics label-free approach based on the biotin switch assay technique with biotin-HPDP and N-ethylmaleimide was used to assess the thiol-oxidized protein profile. Aconitase was oxidized at Cys-448 and Cys-451, citrate synthase was oxidized at Cys-202 and aspartate aminotransferase (Got2) was oxidized at Cys-272 and Cys-274, exclusively after melanogenesis stimulation. After RB-PDT, only guanine nucleotide-binding protein subunit beta-2-like 1 (Gnb2l1) was oxidized (Cys-168). In contrast, melanogenesis stimulation followed by RB-PDT led to the oxidation of different cysteines in Gnb2l1 (Cys-153 and Cys-249). Besides that, glyceraldehyde-3-phosphate dehydrogenase (Gapdh) presented oxidation at Cys-245, peptidyl-prolyl cis-trans isomerase A (Ppia) was oxidized at Cys-161 and 5,6-dihydroxyindole-2-carboxylic acid oxidase (Tyrp1) was oxidized at Cys-65, Cys-30, and Cys-336 after melanogenesis stimulation followed by RB-PDT. The redox alterations observed in murine melanoma cells and identification of possible target proteins are of great importance to further understand tumor resistance mechanisms.

Identification of a novel lactylation-related gene signature predicts the prognosis of multiple myeloma and experiment verification

Multiple myeloma (MM) is an incurable hematological malignancy with poor survival. Accumulating evidence reveals that lactylation modification plays a vital role in tumorigenesis. However, research on lactylation-related genes (LRGs) in predicting the prognosis of MM remains limited. Differentially expressed LRGs (DELRGs) between MM and normal samples were investigated from the Gene Expression Omnibus database. Univariate Cox regression and LASSO Cox regression analysis were applied to construct gene signature associated with overall survival. The signature was validated in two external datasets. A nomogram was further constructed and evaluated. Additionally, Enrichment analysis, immune analysis, and drug chemosensitivity analysis between the two groups were investigated. qPCR and immunofluorescence staining were performed to validate the expression and localization of PFN1. CCK-8 and flow cytometry were performed to validate biological function. A total of 9 LRGs (TRIM28, PPIA, SOD1, RRP1B, IARS2, RB1, PFN1, PRCC, and FABP5) were selected to establish the prognostic signature. Kaplan-Meier survival curves showed that high-risk group patients had a remarkably worse prognosis in the training and validation cohorts. A nomogram was constructed based on LRGs signature and clinical characteristics, and showed excellent predictive power by calibration curve and C-index. Moreover, biological pathways, immunologic status, as well as sensitivity to chemotherapy drugs were different between high- and low-risk groups. Additionally, the hub gene PFN1 is highly expressed in MM, knocking down PFN1 induces cell cycle arrest, suppresses cell proliferation and promotes cell apoptosis. In conclusion, our study revealed that LRGs signature is a promising biomarker for MM that can effectively early distinguish high-risk patients and predict prognosis.

Mitochondrial protein isoleucyl-tRNA synthetase 2 in tumor cells as a potential therapeutic target for cervical cancer

Objective

Isoleucyl-tRNA synthetase 2 (IARS2) is crucial for mitochondrial activity and function in cancer cells. Cervical cancer is a highly prevalent malignancy affecting the female reproductive system on a global scale. This research investigates the expression and potential roles of IARS2 in cervical cancer cells.

Material and Methods

Initially, we examined the IARS2 expression profile in cervical cancer cells using Western blot technique and quantitative reverse transcription polymerase chain reaction methodologies. Subsequently, cervical cancer cell models with IARS2 silencing and overexpression were constructed using Short Hairpin RNA (ShRNA) (IARS2) and pcMV-FLAG-IARS2, respectively. The impact of IARS2 silencing or overexpression on Hela cell mitochondrial membrane potential, mitochondrial complex I, adenosine triphosphate (ATP) levels, reactive oxygen species activity, viability, proliferation, migration, apoptosis-related proteins, and apoptosis levels was examined through fluorescence staining, enzyme-linked immunosorbent assay, cell counting kit-8 assay, Transwell experiments, Western blot technique, and Terminal deoxynucleotidyl transferase dUTP nick end labeling assay techniques.

Results

The expression of IARS2 is upregulated in cervical cancer cells. Silencing IARS2 with ShRNA (IARS2) disrupts mitochondrial function in cervical cancer cells, resulting in mitochondrial depolarization, heightened oxidative stress, suppression of mitochondrial complex I, and a decrease in ATP levels. Moreover, the depletion of IARS2 significantly impedes the viability, proliferation, and migration of cervical cancer cells, inducing apoptotic processes. In contrast, the overexpression of IARS2 augments the proliferation, migration, and ATP levels in cervical cancer cells.

Conclusion

IARS2 plays a pivotal role as a mitochondrial protein in fostering the growth of cervical cancer cells, presenting itself as an innovative target for tumor diagnosis and treatment.

Lentivirus-induced knockdown of IARS2 expression inhibits the proliferation and promotes the apoptosis of human osteosarcoma cells

Isoleucyl-tRNA synthetase 2 (IARS2), distributed in mitochondria, is an IARS involved in protein synthesis. Notably, IARS2 has been reported to be associated with tumor progression; however, the relationship between osteosarcoma (OS) and IARS2 remains unclear. To investigate the role of IARS2 in human OS, the expression and relationship of IARS2 with survival were firstly analyzed using the Gene Expression Profiling Interactive Analysis 2 database. Subsequently, an IARS2-short hairpin RNA lentiviral vector was established and used to infect the MNNG/HOS and U2OS cell lines. Reverse transcription-quantitative PCR (RT-qPCR) and western blotting were applied to determine the efficiency of IARS2 knockdown. The effects of IARS2 knockdown on cell proliferation, colony formation and apoptosis were evaluated by Celigo, MTT assays, colony formation assays and flow cytomeric analysis. In the present study, IARS2 tends to be high expressed in OS tissue and was associated with survival but this was not significant. The results of RT-qPCR and western blotting showed that the expression of IARS2 was effectively knocked down in the MNNG/HOS and U2OS cell lines. Celigo, MTT and colony formation assays showed that IARS2 knockdown in MNNG/HOS and U2OS cell lines inhibited cell proliferation and colony formation compared with in the control group. Flow cytometric analysis revealed that IARS2 knockdown increased apoptosis. These results suggested that IARS2 may be critical for the proliferation and apoptosis of OS cells.

New Insights Into Human Hyaluronidase 4/Chondroitin Sulphate Hydrolase

In this review, the current experimental evidence, literature and hypotheses surrounding hyaluronidase 4 [HYAL4, also known as chondroitin sulphate hydrolase (CHSE)] and chondroitin sulphate (CS) are explored. Originally named for its sequence similarity to other members of the hyaluronidase family, HYAL4 is actually a relatively distinct member of the family, particularly for its unique degradation of CS-D (2-O-, 6-O-sulphated CS) motifs and specific expression. Human HYAL4 protein expression and structural features are discussed in relation to different isoforms, activities, potential localisations and protein-protein interaction partners. CS proteoglycan targets of HYAL4 activity include: serglycin, aggrecan, CD44 and sulfatase 2, with other potential proteoglycans yet to be identified. Importantly, changes in HYAL4 expression changes in human disease have been described for testicular, bladder and kidney cancers, with gene mutations reported for several others including: leukaemia, endometrial, ovarian, colorectal, head and neck, stomach, lung and breast cancers. The HYAL4 gene also plays a role in P53 negative human cancer cell proliferation and is linked to stem cell naivety. However, its role in cancer remains relatively unexplored. Finally, current tools and techniques for the detection of specific HYAL4 activity in biological samples are critically assessed. Understanding the role of HYAL4 in human diseases will fortify our understanding of developmental processes and disease manifestation, ultimately providing novel diagnostic opportunities and therapeutic targets for drug discovery.