Epithelial-mesenchymal transition induced by tumor cell-intrinsic PD-L1 signaling predicts a poor response to immune checkpoint inhibitors in PD-L1-high lung cancer.

BACKGROUND: We investigated the role of tumor cell-intrinsic PD-L1 signaling in the epithelial-mesenchymal transition (EMT) in non-small-cell lung cancer (NSCLC) and the role of EMT as a predictive biomarker for immune checkpoint inhibitor (ICI) therapy. METHODS: PD-L1-overexpressing or PD-L1-knockdown NSCLC cells underwent RNA-seq and EMT phenotype assessment. Mouse lung cancer LLC cells were injected into nude mice. Two cohorts of patients with NSCLC undergoing ICI therapy were analyzed. RESULTS: RNA-seq showed that EMT pathways were enriched in PD-L1-high NSCLC cells. EMT was enhanced by PD-L1 in NSCLC cells, which was mediated by transforming growth factor-ß (TGFß). PD-L1 promoted the activation of p38-MAPK by binding to and inhibiting the protein phosphatase PPM1B, thereby increasing the TGFß production. Tumor growth and metastasis increased in nude mice injected with PD-L1-overexpressing LLC cells. In the ICI cohort, EMT signature was higher in patients with progressive disease than in those with responses, and EMT was significantly associated with poor survival in PD-L1-high NSCLC. In PD-L1-high NSCLC, EMT was associated with increased M2-macrophage and regulatory T-cell infiltrations and decreased cytotoxic T-cell infiltration. CONCLUSIONS: Tumor cell-intrinsic PD-L1 function contributes to NSCLC progression by promoting EMT. EMT may predict an unfavorable outcome after ICI therapy in PD-L1-high NSCLC.

Neuroprotective Effects of Licochalcone D in Oxidative-Stress-Induced Primitive Neural Stem Cells from Parkinson's Disease Patient-Derived iPSCs.

Parkinson's disease (PD) is one of the most common neurodegenerative diseases caused by the loss of dopaminergic neurons in the substantia nigra pars compacta. Although the etiology of PD is still unclear, the death of dopaminergic neurons during PD progression was revealed to be associated with abnormal aggregation of α-synuclein, elevation of oxidative stress, dysfunction of mitochondrial functions, and increased neuroinflammation. In this study, the effects of Licochalcone D (LCD) on MG132-induced neurotoxicity in primitive neural stem cells (pNSCs) derived from reprogrammed iPSCs were investigated. A cell viability assay showed that LCD had anti-apoptotic properties in MG132-induced oxidative-stressed pNSCs. It was confirmed that apoptosis was reduced in pNSCs treated with LCD through 7-AAD/Annexin Ⅴ staining and cleaved caspase3. These effects of LCD were mediated through an interaction with JunD and through the EGFR/AKT and JNK signaling pathways. These findings suggest that LCD could be a potential antioxidant reagent for preventing disease-related pathological phenotypes of PD.

Acceleration of Mesenchymal-to-Epithelial Transition (MET) during Direct Reprogramming Using Natural Compounds.

Induced pluripotent stem cells (iPSCs) can be generated from somatic cells using Oct4, Sox2, Klf4, and c-Myc (OSKM). Small molecules can enhance reprogramming. Licochalcone D (LCD), a flavonoid compound present mainly in the roots of Glycyrrhiza inflata, acts on known signaling pathways involved in transcriptional activity and signal transduction, including the PGC1-α and MAPK families. In this study, we demonstrated that LCD improved reprogramming efficiency. LCD-treated iPSCs (LCD-iPSCs) expressed pluripotency-related genes Oct4, Sox2, Nanog, and Prdm14. Moreover, LCD-iPSCs differentiated into all three germ layers in vitro and formed chimeras. The mesenchymal-to-epithelial transition (MET) is critical for somatic cell reprogramming. We found that the expression levels of mesenchymal genes (Snail2 and Twist) decreased and those of epithelial genes (DSP, Cldn3, Crb3, and Ocln) dramatically increased in OR-MEF (OG2+/+/ROSA26+/+) cells treated with LCD for 3 days, indicating that MET effectively occurred in LCD-treated OR-MEF cells. Thus, LCD enhanced the generation of iPSCs from somatic cells by promoting MET at the early stages of reprogramming.

Deoxypodophyllotoxin Induces ROS-Mediated Apoptosis by Modulating the PI3K/AKT and p38 MAPK-Dependent Signaling in Oral Squamous Cell Carcinoma.

Deoxypodophyllotoxin (DPT), a naturally occurring flavonolignan, possesses several pharmacological properties, including anticancer property. However, the mechanisms underlying DPT mode of action in oral squamous cell carcinoma (OSCC) remain unknown. This study aimed to investigate the anticancer effects of DPT on OSCC and the underlying mechanisms. Results of the MTT assay revealed that DPT significantly reduced the cell viability in a time- and dose-dependent manner. Flow cytometry analysis revealed that DPT induces apoptosis in OSCC cells in a dose-dependent manner. Moreover, DPT enhanced the production of mitochondrial reactive oxygen species (ROS) in OSCC cells. Mechanistically, DPT induced apoptosis in OSCC cells by suppressing the PI3K/AKT signaling pathway while activating the p38 MAPK signaling to regulate the expression of apoptotic proteins. Treatment with SC79, an AKT activator, reversed the effects of DPT on AKT signaling in OSCC cells. Taken together, these results provide the basis for the use of DPT in combination with conventional chemotherapy for the treatment of oral cancer.

Licochalcone H Induces Cell Cycle Arrest and Apoptosis in Human Skin Cancer Cells by Modulating JAK2/STAT3 Signaling.

Licochalcone H (LCH) is a phenolic compound synthetically derived from licochalcone C (LCC) that exerts anticancer activity. In this study, we investigated the anticancer activity of LCH in human skin cancer A375 and A431 cells. The 3-(4,5-dimethylthiazol- 2-yl)-5-(3-carboxymethoxyphenyl)-2-(4-sulfophenyl)-2H-tetrazolium (MTS) cell viability assay was used to evaluate the antiproliferative activity of LCH. Cell cycle distribution and the induction of apoptosis were analyzed by flow cytometry. Western blotting assays were performed to detect the levels of proteins involved in cell cycle progression, apoptosis, and the JAK2/STAT3 signaling pathway. LCH inhibited the growth of cells in dose- and time-dependent manners. The annexin V/propidium iodide double staining assay revealed that LCH induced apoptosis, and the LCH-induced apoptosis was accompanied by cell cycle arrest in the G1 phase. Western blot analysis showed that the phosphorylation of JAK2 and STAT3 was decreased by treatment with LCH. The inhibition of the JAK2/STAT3 signaling pathway by pharmacological inhibitors against JAK2/STAT3 (cryptotanshinone (CTS) and S3I-201) simulated the antiproliferative effect of LCH suggesting that LCH induced apoptosis by modulating JAK2/STAT3 signaling.

Global Proteomic Analysis of Mesenchymal Stem Cells Derived from Human Embryonic Stem Cells via Connective Tissue Growth Factor Treatment under Chemically Defined Feeder-Free Culture Conditions.

Stem cells can be applied usefully in basic research and clinical field due to their differentiation and self-renewal capacity. The aim of this study was to establish an effective novel therapeutic cellular source and create its molecular expression profile map to elucidate the possible therapeutic mechanism and signaling pathway. We successfully obtained a mesenchymal stem cell population from human embryonic stem cells (hESCs) cultured on chemically defined feeder-free conditions and treated with connective tissue growth factor (CTGF) and performed the expressive proteomic approach to elucidate the molecular basis. We further selected 12 differentially expressed proteins in CTGF-induced hESC-derived mesenchymal stem cells (C-hESC-MSCs), which were found to be involved in the metabolic process, immune response, cell signaling, and cell proliferation, as compared to bone marrow derived-MSCs(BM-MSCs). Moreover, these up-regulated proteins were potentially related to the Wnt/ß-catenin pathway. These results suggest that C-hESC-MSCs are a highly proliferative cell population, which can interact with the Wnt/ß-catenin signaling pathway; thus, due to the upregulated cell survival ability or downregulated apoptosis effects of C-hESC-MSCs, these can be used as an unlimited cellular source in the cell therapy field for a higher therapeutic potential. Overall, the study provided valuable insights into the molecular functioning of hESC derivatives as a valuable cellular source.

3'-UTR Polymorphisms in Thymidylate Synthase with Colorectal Cancer Prevalence and Prognosis.

Colorectal cancer (CRC) is the third most common type of cancer and the second leading cause of cancer-related mortality in Western countries. Polymorphisms in one-carbon metabolism and angiogenesis-related genes have been shown to play important roles in tumor development, progression, and metastasis for many cancers, including CRC. Moreover, recent studies have reported that polymorphisms in specific microRNA (miRNA)-binding regions, which are located in the 3'-untranslated region (UTR) of miRNA-regulated genes, are present in a variety of cancers. Here, we investigated the association between two thymidylate synthase (TYMS or TS) 3'-UTR polymorphisms, 1100T>C [rs699517] and 1170A>G [rs2790], and CRC susceptibility and progression in Korean patients. A total of 450 CRC patients and 400 healthy controls were enrolled in this study, and genotyping at the TS locus was performed by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) or TaqMan allelic discrimination assays. We found that TS 1170A>G genotypes, as well as the TS 1100T-1170G and 1100C-1170A haplotypes, are strongly associated with CRC. The TS 1100TC+CC type was associated with a poor survival (OS and RFS) rate. In addition, levels of the TS 1100C and TS 1170G allele were found to be significantly increased in CRC tissue. Our study provides the first evidence for 3'-UTR variants in TS genes as potential biomarkers of CRC prognosis and prevention.

Quantitative Proteomic Analysis of Primitive Neural Stem Cells from LRRK2 G2019S-Associated Parkinson's Disease Patient-Derived iPSCs.

Parkinson's disease (PD) is a common neurodegenerative disease, causing movement defects. The incidence of PD is constantly increasing and this disease is still incurable. Thus, understanding PD pathophysiology would be pivotal for the development of PD therapy, and various PD models have thus been already developed. Through recent advances in reprogramming techniques, a primitive neural stem cell (pNSC) derived from PD patient induced pluripotent stem cells (iPSCs) could be potentially used as a reproducible and reliable experimental system to analyze the effect of the leucine-rich repeat kinase 2 G2019S mutation (LK2GS) in neural cells. Here, we investigated the advantages of such a model system through quantitative proteomic analysis of pNSCs from normal control iPSCs and familial PD patient iPSCs harboring LK2GS. We confirmed that the expression of molecules known to be involved in PD pathogenesis, such as oxidative stress-, cell adhesion-, and cytoskeleton-related proteins, were altered in the LK2GS pNSC. In addition, we showed that down-regulation of Ku80, which was found in the proteomic analysis with LK2GS pNSCs, resulted in apoptosis induced by DNA damage response. Taken together, we suggest that pNSCs from PD iPSCs could provide a reliable and useful model system to study PD. Moreover, the highly expandable pNSC is suitable for multi-omics approaches to understand PD pathologies and discover therapeutic targets for PD.

Neuroprotective Effects of Cryptotanshinone in a Direct Reprogramming Model of Parkinson's Disease.

Parkinson's disease (PD) is a well-known age-related neurodegenerative disease. Considering the vital importance of disease modeling based on reprogramming technology, we adopted direct reprogramming to human-induced neuronal progenitor cells (hiNPCs) for in vitro assessment of potential therapeutics. In this study, we investigated the neuroprotective effects of cryptotanshinone (CTN), which has been reported to have antioxidant properties, through PD patient-derived hiNPCs (PD-iNPCs) model with induced oxidative stress and cell death by the proteasome inhibitor MG132. A cytotoxicity assay showed that CTN possesses anti-apoptotic properties in PD-hiNPCs. CTN treatment significantly reduced cellular apoptosis through mitochondrial restoration, such as the reduction in mitochondrial reactive oxygen species and increments of mitochondrial membrane potential. These effects of CTN are mediated via the nuclear factor erythroid 2-related factor 2 (NRF2) pathway in PD-hiNPCs. Consequently, CTN could be a potential antioxidant reagent for preventing disease-related pathological phenotypes of PD.

Iroquois Homeobox Protein 2 Identified as a Potential Biomarker for Parkinson's Disease.

The diagnosis of Parkinson's disease (PD) is initiated after the occurrence of motor symptoms, such as resting tremors, rigidity, and bradykinesia. According to previous reports, non-motor symptoms, notably gastrointestinal dysfunction, could potentially be early biomarkers in PD patients as such symptoms occur earlier than motor symptoms. However, connecting PD to the intestine is methodologically challenging. Thus, we generated in vitro human intestinal organoids from PD patients and ex vivo mouse small intestinal organoids from aged transgenic mice. Both intestinal organoids (IOs) contained the human LRRK2 G2019S mutation, which is the most frequent genetic cause of familial and sporadic PD. By conducting comprehensive genomic comparisons with these two types of IOs, we determined that a particular gene, namely, Iroquois homeobox protein 2 (IRX2), showed PD-related expression patterns not only in human pluripotent stem cell (PSC)-derived neuroectodermal spheres but also in human PSC-derived neuronal cells containing dopaminergic neurons. We expected that our approach of using various cell types presented a novel technical method for studying the effects of multi-organs in PD pathophysiology as well as for the development of diagnostic markers for PD.

Licochalcone C induces cell cycle G1 arrest and apoptosis in human esophageal squamous carcinoma cells by activation of the ROS/MAPK signaling pathway.

Along with changes in dietary habits and lifestyle, the incidence of esophageal cancer is increasing around the world. Since chemotherapy for esophageal cancer has significant side effects, phytochemicals have attracted attention as an alternative medicine. Licochalcone C (LCC) is a flavonoid compound extracted from Licorice, with a variety of clinical uses including anti-cancer, anti-inflammatory and anti-oxidant effects. Treatment with LCC for 48 h significantly decreased cell viability of esophageal squamous cell carcinoma (ESCC) cells in a dose- and time-dependent manner with IC50 values of 28 µM (KYSE 30), 36 µM (KYSE 70), 19 µM (KYSE 410), 28 µM (KYSE 450) and 26 µM (KYSE 510). LCC induced G1 arrest accompanied by decreased cyclin D1 expression and an increase in the levels of p21 and p27. LCC increased the levels of intracellular ROS, cytochrome C release, and multi-caspase activity, and decreased mitochondrial membrane potential. LCC induced the protein expression of ER stress markers (GRP78 and CHOP) and phosphorylation JNK, c-Jun and p38. We investigated the expression of pro-apoptotic and anti-apoptotic proteins to elucidate the mechanism of apoptosis. Our findings contribute to the understanding of apoptosis mechanism underlying LCC in ESCC cells and provide new insights into the potential clinical opportunities of LCC for ESCC treatment.

Direct Reprogramming to Human Induced Neuronal Progenitors from Fibroblasts of Familial and Sporadic Parkinson's Disease Patients.

In Parkinson's disease (PD) research, human neuroblastoma and immortalized neural cell lines have been widely used as in vitro models. The advancement in the field of reprogramming technology has provided tools for generating patient-specific induced pluripotent stem cells (hiPSCs) as well as human induced neuronal progenitor cells (hiNPCs). These cells have revolutionized the field of disease modeling, especially in neural diseases. Although the direct reprogramming to hiNPCs has several advantages over differentiation after hiPSC reprogramming, such as the time required and the simple procedure, relatively few studies have utilized hiNPCs. Here, we optimized the protocol for hiNPC reprogramming using pluripotency factors and Sendai virus. In addition, we generated hiNPCs of two healthy donors, a sporadic PD patient, and a familial patient with the LRRK2 G2019S mutation (L2GS). The four hiNPC cell lines are highly proliferative, expressed NPC markers, maintained the normal karyotype, and have the differentiation potential of dopaminergic neurons. Importantly, the patient hiNPCs show different apoptotic marker expression. Thus, these hiNPCs, in addition to hiPSCs, are a favorable option to study PD pathology.

Genomic analysis of Korean patients with advanced prostate cancer by use of a comprehensive next-generation sequencing panel and low-coverage, whole-genome sequencing.

Purpose: To analyze the characteristics of somatic mutations and copy number alterations (CNAs) in Korean patients with advanced prostate cancer (PCa) by use of the Oncomine Comprehensive Panel (ThermoFisher Scientific) and low-coverage, whole-genome sequencing (LC-WGS). Materials and Methods: We retrospectively analyzed PCa tissues obtained from 14 patients with advanced PCa (metastatic tumor, 12 [85.7%]; nonmetastatic castration-resistant PCa, 1 [7.1%]; pT3b, 1 [7.1%]) from 2009 to 2017. The Oncomine Comprehensive Panel included a total of 143 genes. Moreover, LC-WGS was performed to detect CNAs of the entire genome. Two plasma samples matched with tumor tissues were analyzed using LC-WGS to compare the chromosomal aberration patterns between circulating tumor DNA and tumor tissue. Results: Genetic alterations were most frequently observed in the androgen receptor (AR) (42.9%, n=6/14), TP53 (14.3%, n=2/14), and PTEN (14.3%, n=2/14) genes in the Oncomine panel. AR amplification was the most common CNA (35.7%, n=5/14). As a result of LC-WGS, CNAs were confirmed in about 92.9% (n=13/14) of the samples in regions Xq12, 8q24.21, and 11q13.3 (gains) and in regions 6q16.1, 8p23.1, 10q25.1, 16q24.2, 18q12.3, Xq25, and Xq26.3 (losses). All CNAs identified in the Oncomine panel matched the results of LC-WGS. Additionally, LC-WGS of two plasma samples that matched tumor tissues revealed that CNA patterns of plasma samples (circulating tumor DNA) were very similar to those detected in tumor samples. Conclusions: Our data showed that the characteristics of mutations and CNAs in Korean patients with advanced PCa were similar to those observed in previous studies.

ω3-polyunsaturated fatty acids induce cell death through apoptosis and autophagy in glioblastoma cells: In vitro and in vivo.

Among brain tumors, glioblastoma (GBM) is the most aggressive type and is associated with the lowest patient survival rate. Numerous lines of evidence have established that omega-3-polyunsaturated fatty acids (ω3-PUFAs) have potential for the prevention and therapy of several types of cancers. Docosahexaenoic acid (DHA), an ω3-PUFA, was reported to inhibit growth and induce apoptotic and autophagic cell death in several cancer cell lines; however, its effects on GBM cells are still unknown. in the present study, we examined the cytotoxic effect of DHA on the GBM cell lines, D54MG, U87MG, U251MG and GL261. Treatment of GBM cells with DHA induced PARP cleavage, increased the population of sub-G1 cells, and increased the number of TUNEL-positive cells, which are all indicative of apoptosis. Furthermore, treatment of GBM cells with DHA resulted in a significant increase in autophagic activity, as revealed by increased LC3-II levels, GFP-LC3 puncta, and autophagic flux activation, accompanied by activation of 5'-AMP-activated protein kinase (AMPK) and decreases in phosphorylated Akt (p-AktSer473) levels and mTOR activity. In vivo, endogenous expression of Caenorhabditis elegans ω3-desaturase, which converts ω6-PUFAs to ω3-PUFAs, in fat-1 transgenic mice yielded a significant decrease in tumor volume following subcutaneous injection of mouse glioma cells (GL261), when compared with wild-type mice. TUNEL-positive cell numbers and LC3-II levels were elevated in tumor tissue from the fat-1 transgenic mice compared with tumor tissue from the wild-type mice. In addition, p-Akt levels were decreased and p-AMPK levels were increased in tumor tissue from the fat-1 transgenic mice. These results indicate that ω3-PUFAs induce cell death through apoptosis and autophagy in GBM cells; thus, it may be possible to use ω3-PUFAs as chemopreventive and therapeutic agents for GBM.

Esculetin exerts anti-proliferative effects against non-small-cell lung carcinoma by suppressing specificity protein 1 in vitro.

Esculetin, a coumarin derivative, is a phenolic compound isolated from Artemisia capillaris, Citrus limonia, and Euphorbia lathyris. Although it has been reported to have anti-inflammatory, anti-oxidant, and anti-proliferative activities in several human cancers, its anti-proliferative activity against non-small-cell lung carcinoma (NSCLC) and the molecular mechanisms involved have not been adequately elucidated. In this study, we used two NSCLC cell lines (NCI-H358 and NCI-H1299) to investigate the anti-proliferative activity and apoptotic effect of esculetin. Our data showed that esculetin-treated cells exhibited reduced proliferation and apoptotic cell morphologies. Intriguingly, the transcription factor specificity protein 1 (Sp1) was significantly suppressed by esculetin in a dose- and time-dependent manner. Furthermore, the levels of p27 and p21, two key regulators of the cell cycle, were up-regulated by the esculetin-mediated down-regulation of Sp1; the level of a third cell-cycle regulator, survivin, was decreased, resulting in caspase-dependent apoptosis. Therefore, we conclude that esculetin could be a potent anti-proliferative agent in patients with NSCLC.

Kahweol induces apoptosis by suppressing BTF3 expression through the ERK signaling pathway in non-small cell lung cancer cells.

Kahweol, a diterpene molecule, has antiproliferative effects on several types of human cancer cells, but whether it has apoptotic effect in non-small cell lung cancer (NSCLC) is not known. To explore this possibility, we incubated cells from two NSCLC cell lines, NCI-H358 and NCI­H1299, with different concentrations of kahweol and used the MTS assay, DAPI staining, propidium iodide staining, Annexin V staining, immunocytochemical test, and western blot analysis to characterize this molecule and the signaling pathway underlying its effects. The kahweol-treated cells showed significantly decreased cell viability, increased nuclear condensation, and an increased number of Annexin V-positive NSCLC cells. Suppression of basic transcription factor 3 (BTF3) was followed by apoptosis induced by kahweol via the ERK-mediated signaling pathway in a dose- and time-dependent manner. In addition, kahweol modulated the protein expression of BTF3 genes involved in cell-cycle regulation and apoptosis-related proteins, resulting in apoptotic cell death. Our results collectively indicated that kahweol inhibited the proliferation of NSCLC cells through ERK-mediated signaling pathways and the downregulation of BTF3.

Regional Differences of Proteins Expressing in Adipose Depots Isolated from Cows, Steers and Bulls as Identified by a Proteomic Approach.

Adipose tissue in the loin muscle area of beef cattle as a marbling factor is directly associated with beef quality. To elucidate whether properties of proteins involved in depot specific adipose tissue were sex-dependent, we analyzed protein expression of intramuscular adipose tissue (IMAT) and omental adipose tissue (OMAT) from Hanwoo cows, steers, and bulls of Korean native beef cattle by liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based proteomic analysis, quantitative polymerase chain reaction (PCR) and western blot analysis. Two different adipose depots (i.e. intramuscular and omental) were collected from cows (n = 7), steers (n = 7), or bulls (n = 7). LC-MS/MS revealed a total of 55 and 35 proteins in IMAT and OMAT, respectively. Of the 55 proteins identified, 44, 40, and 42 proteins were confirmed to be differentially expressed in IMAT of cows, steers, and bulls, respectively. In OMAT of cows, steers, and bulls, 33, 33, and 22 were confirmed to be differentially expressed, respectively. Tropomyosin (TPM) 1, TPM 2, and TPM3 were subjected to verification by quantitative PCR and western blot analysis in IMAT and OMAT of Hanwoo cows, steers, and bulls as key factors closely associated with muscle development. Both mRNA levels and protein levels of TPM1, TPM2, and TPM3 in IMAT were lower in bulls compared to in cows or steers suggesting that they were positively correlated with marbling score and quality grade. Our results may aid the regulation of marbling development and improvement of meat quality grades in beef cattle.

Proteomic Assessment of the Relevant Factors Affecting Pork Meat Quality Associated with Longissimus dorsi Muscles in Duroc Pigs.

Meat quality is a complex trait influenced by many factors, including genetics, nutrition, feeding environment, animal handling, and their interactions. To elucidate relevant factors affecting pork quality associated with oxidative stress and muscle development, we analyzed protein expression in high quality longissimus dorsi muscles (HQLD) and low quality longissimus dorsi muscles (LQLD) from Duroc pigs by liquid chromatographytandem mass spectrometry (LC-MS/MS)-based proteomic analysis. Between HQLD (n = 20) and LQLD (n = 20) Duroc pigs, 24 differentially expressed proteins were identified by LC-MS/MS. A total of 10 and 14 proteins were highly expressed in HQLD and LQLD, respectively. The 24 proteins have putative functions in the following seven categories: catalytic activity (31%), ATPase activity (19%), oxidoreductase activity (13%), cytoskeletal protein binding (13%), actin binding (12%), calcium ion binding (6%), and structural constituent of muscle (6%). Silver-stained image analysis revealed significant differential expression of lactate dehydrogenase A (LDHA) between HQLD and LQLD Duroc pigs. LDHA was subjected to in vitro study of myogenesis under oxidative stress conditions and LDH activity assay to verification its role in oxidative stress. No significant difference of mRNA expression level of LDHA was found between normal and oxidative stress condition. However, LDH activity was significantly higher under oxidative stress condition than at normal condition using in vitro model of myogenesis. The highly expressed LDHA was positively correlated with LQLD. Moreover, LDHA activity increased by oxidative stress was reduced by antioxidant resveratrol. This paper emphasizes the importance of differential expression patterns of proteins and their interaction for the development of meat quality traits. Our proteome data provides valuable information on important factors which might aid in the regulation of muscle development and the improvement of meat quality in longissimus dorsi muscles of Duroc pigs under oxidative stress conditions.