Induction of STK11-dependent cytoprotective autophagy in breast cancer cells upon honokiol treatment

Honokiol induces apoptosis and autophagy in dexamethasone-resistant T-acute lymphoblastic leukemia CEM-C1 cells

Objective: To study whether and, if so, how honokiol overcome dexamethasone resistance in DEX-resistant CEM-C1 cells. Methods: We investigated the effect of honokiol (0-20 µM) on cell proliferation, cell cycle, cell apoptosis and autophagy in DEX-resistant CEM-C1 cells and DEX-sensitive CEM-C7 cells. We also determined the role of c-Myc protein and mRNA in the occurrence of T-ALL associated dexamethasone resistance western blot and reverse transcription-qPCR (RT-qPCR) analysis. Results: Cell Counting Kit (CCK)-8 assay shows that DEX-resistant CEM-C1 cell lines were highly resistant to dexamethasone with IC50 of 364.1 ± 29.5 µM for 48 h treatment. However, upon treatment with dexamethasone in combination with 1.5 µM of honokiol for 48 h, the IC50 of CEM-C1 cells significantly decreased to 126.2 ± 12.3 µM, and the reversal fold was 2.88. Conversely, the IC50 of CEM-C7 cells was not changed combination of dexamethasone and honokiol as compared to that of CEM-C7 cells treated with dexamethasone alone. It has been shown that honokiol induced T-ALL cell growth inhibition by apoptosis and autophagy via downregulating cell cycle-regulated proteins (Cyclin E, CDK4, and Cyclin D1) and anti-apoptotic proteins BCL-2 and upregulating pro-apoptotic proteins Bax and led to PARP cleavage. Honokiol may overcome dexamethasone resistance in DEX-resistant CEM-C1 cell lines via the suppression of c-Myc mRNA expression. Conclusion: The combination of honokiol and DEX were better than DEX alone in DEX-resistant CEM-C1 cell lines. Honokiol may regulate T-ALL-related dexamethasone resistance by affecting c-Myc.

FBXL19 Targeted STK11 Degradation Enhances Cigarette Smoke-Induced Airway Epithelial Cell Cytotoxicity

Objective: To investigate the effects of cigarette smoke (CS) on Serine/Threonine Kinase 11 (STK11) and to determine STK11's role in CS-induced airway epithelial cell cytotoxicity.Methods: STK11 expression levels in the lung tissues of smokers with or without COPD and mice exposed to CS or room air (RA) were determined by immunoblotting and RT-PCR. BEAS-2Bs-human bronchial airway epithelial cells were exposed to CS extract (CSE), and the changes in STK11 expression levels were determined by immunoblotting and RT-PCR. BEAS-2B cells were transfected with STK11-specific siRNA or STK11 expression plasmid, and the effects of CSE on airway epithelial cell cytotoxicity were measured. To determine the specific STK11 degradation-proteolytic pathway, BEAS-2Bs were treated with cycloheximide alone or combined with MG132 or leupeptin. Finally, to identify the F-box protein mediating the STK11 degradation, a screening assay was performed using transfection with a panel of FBXL E3 ligase subunits.Results: STK11 protein levels were significantly decreased in the lung tissues of smokers with COPD relative to smokers without COPD. STK11 protein levels were also significantly decreased in mouse lung tissues exposed to CS compared to RA. Exposure to CSE shortened the STK11 mRNA and protein half-life to 4 h in BEAS-2B cells. STK11 protein overexpression attenuated the CSE-induced cytotoxicity; in contrast, its knockdown augmented CSE-induced cytotoxicity. FBXL19 mediates CSE-induced STK11 protein degradation via the ubiquitin-proteasome pathway in cultured BEAS-2B cells. FBXL19 overexpression led to accelerated STK11 ubiquitination and degradation in a dose-dependent manner.Conclusions: Our results suggest that CSE enhances the degradation of STK11 protein in airway epithelial cells via the FBXL19-mediated ubiquitin-proteasomal pathway, leading to augmented cell death.HIGHLIGHTSLung tissues of COPD-smokers exhibited a decreased STK11 RNA and protein expression.STK11 overexpression attenuates CS-induced airway epithelial cell cytotoxicity.STK11 depletion augments CS-induced airway epithelial cell cytotoxicity.CS diminishes STK11 via FBXL19-mediated ubiquitin-proteasome degradation.

Exploiting Nanotechnology for Drug Delivery: Advancing the Anti-Cancer Effects of Autophagy-Modulating Compounds in Traditional Chinese Medicine

Background

Cancer continues to be a prominent issue in the field of medicine, as demonstrated by recent studies emphasizing the significant role of autophagy in the development of cancer. Traditional Chinese Medicine (TCM) provides a variety of anti-tumor agents capable of regulating autophagy. However, the clinical application of autophagy-modulating compounds derived from TCM is impeded by their restricted water solubility and bioavailability. To overcome this challenge, the utilization of nanotechnology has been suggested as a potential solution. Nonetheless, the current body of literature on nanoparticles delivering TCM-derived autophagy-modulating anti-tumor compounds for cancer treatment is limited, lacking comprehensive summaries and detailed descriptions.

Methods

Up to November 2023, a comprehensive research study was conducted to gather relevant data using a variety of databases, including PubMed, ScienceDirect, Springer Link, Web of Science, and CNKI. The keywords utilized in this investigation included "autophagy", "nanoparticles", "traditional Chinese medicine" and "anticancer".

Results

This review provides a comprehensive analysis of the potential of nanotechnology in overcoming delivery challenges and enhancing the anti-cancer properties of autophagy-modulating compounds in TCM. The evaluation is based on a synthesis of different classes of autophagy-modulating compounds in TCM, their mechanisms of action in cancer treatment, and their potential benefits as reported in various scholarly sources. The findings indicate that nanotechnology shows potential in enhancing the availability of autophagy-modulating agents in TCM, thereby opening up a plethora of potential therapeutic avenues.

Conclusion

Nanotechnology has the potential to enhance the anti-tumor efficacy of autophagy-modulating compounds in traditional TCM, through regulation of autophagy.

Upregulation of tumor suppressor PIAS3 by Honokiol promotes tumor cell apoptosis via selective inhibition of STAT3 tyrosine 705 phosphorylation

The natural product Honokiol exhibits robust antitumor activity against a range of cancers, and it has also received approval to undergo phase I clinical trial testing. We confrmed that honokiol can promote the apoptotic death of tumor cells through cell experiments. Then siRNA constructs specific for PIAS3, PIAS3 overexpression plasmid and the mutation of the STAT3 Tyr705 residue were used to confirm the mechanism of Honokiol-induced apoptosis. Finally, we confrmed that honokiol can promote PIAS3 upregulation, in turn suppressing STAT3 Tyr705 phosphorylation through the in vivo and in vitro experiments. Honokiol was ultimately found to reduce tumor cell viability by promoting apoptosis through a mechanism dependent on the ability of Honokiol to promote PIAS3 upregulation and the selective inhibition of p-STAT3 (Tyr705) without affecting p-STAT3 (Ser727) or p-STAT1 (Tyr701) levels. PIAS3 knockdown and overexpression in tumor cells altered STAT3 activation and associated DNA binding activity through the control of Tyr705 phosphorylation via PIAS3-STAT3 complex formation, ultimately shaping Honokiol-induced tumor cell apoptosis. Honokiol was also confirmed to significantly prolong the survival of mice bearing xenograft tumors in a PIAS3-dependent fashion. Together, these findings highlight a novel pathway through which Honokiol can promote PIAS3 upregulation, in turn suppressing STAT3 Tyr705 phosphorylation and promoting the apoptotic death of tumor cells.

Honokiol and its analogues as anticancer compounds: Current mechanistic insights and structure-activity relationship

Lignans are plant-derived polyphenolic compounds with a plethora of biological applications. Also, regarded as phytoestrogens, the lignans offer a variety of health benefits of which the anti-cancer effects are the most attractive. Honokiol is a lignan isolated from various parts of trees belonging to the genus Magnolia. The bioactivity of honokiol is attributed to its characteristic physical properties, which include small size and the presence of two phenolic groups that may interact with proteins in cell membranes via hydrophobic interactions, aromatic pi orbital co-valency, and hydrogen bonding. The hydrophobicity of honokiol enables its rapid dissolution in lipids and the crossing of physiological barriers, including the blood-brain barrier and cerebrospinal fluid. These factors contribute towards the high bioavailability of honokiol which further support its candidature in medicinal research. Therefore, the anticancer properties of honokiol are of particular interest as many of the contemporary anticancer drugs suffer from bioavailability drawbacks, which necessitates the identification and development of novel candidate molecules directed as anticancer chemotherapeutics. The antioncogenic profile of honokiol also arises from the regulation of various signalling pathways associated with oncogenesis, arresting of the cell cycle by regulation of cyclic proteins, upregulation of epithelial markers and downregulation of mesenchymal markers leading to the inhibition of epithelial-mesenchymal transition, and preventing the metastasis by restricting cell migration and invasion due to the downregulation of matrix-metalloproteinases. In this review, we discuss the anticancer properties of honokiol.

Jaboticaba (Myrciaria jaboticaba) peel extracts induce reticulum stress and apoptosis in breast cancer cells

Jaboticaba peel (Myrciaria jaboticaba) is a source of bioactive compounds. We investigated the anticancer activity of ethyl acetate extract (JE1) and hydroethanolic extract (JE2) of Jaboticaba peel against breast cancer. Both JE1 and JE2 inhibited clonogenic potential of MDA-MB-231 cells while JE1 was particularly effective in MCF7 cells. Anchorage-independent growth and cell viability was also inhibited by JE1 and JE2. In addition to growth inhibition, JE1 and JE2 could also inhibit migration and invasion of cells. Interestingly, JE1 and JE2 show selective inhibition towards certain breast cancer cells and biological processes. Mechanistic evaluations showed that JE1 induced PARP cleavage, BAX and BIP indicating apoptotic induction. An elevation of phosphorylated ERK was observed in MCF7 cells in response to JE1 and JE2 along with increased IRE-α and CHOP expression indicating increased endoplasmic stress. Therefore, Jaboticaba peel extracts could be potentially considered for further development for breast cancer inhibition.

Autophagy and Breast Cancer: Connected in Growth, Progression, and Therapy

Despite an increase in the incidence of breast cancer worldwide, overall prognosis has been consistently improving owing to the development of multiple targeted therapies and novel combination regimens including endocrine therapies, aromatase inhibitors, Her2-targeted therapies, and cdk4/6 inhibitors. Immunotherapy is also being actively examined for some breast cancer subtypes. This overall positive outlook is marred by the development of resistance or reduced efficacy of the drug combinations, but the underlying mechanisms are somewhat unclear. It is interesting to note that cancer cells quickly adapt and evade most therapies by activating autophagy, a catabolic process designed to recycle damaged cellular components and provide energy. In this review, we discuss the role of autophagy and autophagy-associated proteins in breast cancer growth, drug sensitivity, tumor dormancy, stemness, and recurrence. We further explore how autophagy intersects and reduces the efficacy of endocrine therapies, targeted therapies, radiotherapy, chemotherapies as well as immunotherapy via modulating various intermediate proteins, miRs, and lncRNAs. Lastly, the potential application of autophagy inhibitors and bioactive molecules to improve the anticancer effects of drugs by circumventing the cytoprotective autophagy is discussed.

Triphenyltin(IV) Carboxylates with Exceptionally High Cytotoxicity against Different Breast Cancer Cell Lines

Organotin(IV) carboxylates are a class of compounds explored as alternatives to platinum-containing chemotherapeutics due to propitious in vitro and in vivo results, and distinct mechanisms of action. In this study, triphenyltin(IV) derivatives of non-steroidal anti-inflammatory drugs (indomethacin (HIND) and flurbiprofen (HFBP)) are synthesized and characterized, namely [Ph3Sn(IND)] and [Ph3Sn(FBP)]. The crystal structure of [Ph3Sn(IND)] reveals penta-coordination of the central tin atom with almost perfect trigonal bipyramidal geometry with phenyl groups in the equatorial positions and two axially located oxygen atoms belonging to two distinct carboxylato (IND) ligands leading to formation of a coordination polymer with bridging carboxylato ligands. Employing MTT and CV probes, the antiproliferative effects of both organotin(IV) complexes, indomethacin, and flurbiprofen were evaluated on different breast carcinoma cells (BT-474, MDA-MB-468, MCF-7 and HCC1937). [Ph3Sn(IND)] and [Ph3Sn(FBP)], unlike the inactive ligand precursors, were found extremely active towards all examined cell lines, demonstrating IC50 concentrations in the range of 0.076–0.200 µM. Flow cytometry was employed to examine the mode of action showing that neither apoptotic nor autophagic mechanisms were triggered within the first 48 h of treatment. However, both tin(IV) complexes inhibited cell proliferation potentially related to the dramatic reduction in NO production, resulting from downregulation of nitric oxide synthase (iNOS) enzyme expression.

Heme-dependent induction of mitophagy program during differentiation of murine erythroid cells

Although establishment and maintenance of mitochondria are essential for the production of massive amounts of heme in erythroblasts, mitochondria must be degraded upon terminal differentiation to red blood cells (RBCs), thus creating a biphasic regulatory process. Previously, we reported that iron deficiency in mice promotes mitochondrial retention in RBCs, suggesting that a proper amount of iron and/or heme is necessary for the degradation of mitochondria during erythroblast maturation. Because the transcription factor GATA1 regulates autophagy in erythroid cells, which involves mitochondrial clearance (mitophagy), we investigated the relationship between iron or heme and mitophagy by analyzing the expression of genes related to GATA1 and autophagy and the impact of iron or heme restriction on the amount of mitochondria. We found that heme promotes the expression of GATA1-regulated mitophagy-related genes and the induction of mitophagy. GATA1 might induce the expression of the autophagy-related genes Atg4d and Stk11 for mitophagy through a heme-dependent mechanism in murine erythroleukemia (MEL) cells and a genetic rescue system with G1E-ER-GATA1 erythroblast cells derived from Gata1-null murine embryonic stem cells. These results provide evidence for a biphasic mechanism in which mitochondria are essential for heme generation, and the heme generated during differentiation promotes mitophagy and mitochondrial disposal. This mechanism provides a molecular framework for understanding this fundamentally important cell biological process.

The Cancer/Testis Antigen CT45A1 Promotes Transcription of Oncogenic Sulfatase-2 Gene in Breast Cancer Cells and Is Sensible Targets for Cancer Therapy

PURPOSE

Invasive breast carcinomas (BRCAs) are highly lethal. The molecular mechanisms underlying progression of invasive BRCAs are unclear, and effective therapies are highly desired. The cancer-testis antigen CT45A1 promotes overexpression of pro-metastatic sulfatase-2 (SULF2) and breast cancer metastasis to the lungs, but its mechanisms are largely unknown. In this study, we aimed to elucidate the mechanism of CT45A1-induced SULF2 overexpression and provide evidence for targeting CT45A1 and SULF2 for breast cancer therapy.

METHODS

The effect of CT45A1 on SULF2 expression was assessed using reverse transcription polymerase chain reaction and western blot. The mechanism of CT45A1-induced SULF2 gene transcription was studied using protein-DNA binding assay and a luciferase activity reporter system. The interaction between CT45A1 and SP1 proteins was assessed using immunoprecipitation and western blot. Additionally, the suppression of breast cancer cell motility by SP1 and SULF2 inhibitors was measured using cell migration and invasion assays.

RESULTS

CT45A1 and SULF2 are aberrantly overexpressed in patients with BRCA; importantly, overexpression of CT45A1 is closely associated with poor prognosis. Mechanistically, gene promoter demethylation results in overexpression of both CT45A1 and SULF2. CT45A1 binds directly to the core sequence GCCCCC in the promoter region of SULF2 gene and activates the promoter. Additionally, CT45A1 interacts with the oncogenic master transcription factor SP1 to drive SULF2 gene transcription. Interestingly, SP1 and SULF2 inhibitors suppress breast cancer cell migration, invasion, and tumorigenicity.

CONCLUSION

Overexpression of CT45A1 is associated with poor prognosis in patients with BRCA. CT45A1 promotes SULF2 overexpression by activating the promoter and interacting with SP1. Additionally, SP1 and SULF2 inhibitors suppress breast cancer cell migration, invasion, and tumorigenesis. Our findings provide new insight into the mechanisms of breast cancer metastasis and highlight CT45A1 and SULF2 as sensible targets for developing novel therapeutics against metastatic breast cancer.

Comprehensive Computational Analysis of Honokiol Targets for Cell Cycle Inhibition and Immunotherapy in Metastatic Breast Cancer Stem Cells

Breast cancer stem cells (BCSCs) play a critical role in chemoresistance, metastasis, and poor prognosis of breast cancer. BCSCs are mostly dormant, and therefore, activating them and modulating the cell cycle are important for successful therapy against BCSCs. The tumor microenvironment (TME) promotes BCSC survival and cancer progression, and targeting the TME can aid in successful immunotherapy. Honokiol (HNK), a bioactive polyphenol isolated from the bark and seed pods of Magnolia spp., is known to exert anticancer effects, such as inducing cell cycle arrest, inhibiting metastasis, and overcoming immunotherapy resistance in breast cancer cells. However, the molecular mechanisms of action of HNK in BCSCs, as well as its effects on the cell cycle, remain unclear. This study aimed to explore the potential targets and molecular mechanisms of HNK on metastatic BCSC (mBCSC)-cell cycle arrest and the impact of the TME. Using bioinformatics analyses, we predicted HNK protein targets from several databases and retrieved the genes differentially expressed in mBCSCs from the GEO database. The intersection between the differentially expressed genes (DEGs) and the HNK-targets was determined using a Venn diagram, and the results were analyzed using a protein-protein interaction network, hub gene selection, gene ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses, genetic alteration analysis, survival rate, and immune cell infiltration levels. Finally, the interaction between HNK and two HNK-targets regulating the cell cycle was analyzed using molecular docking analysis. The identified potential therapeutic targets of HNK (PTTH) included CCND1, SIRT2, AURKB, VEGFA, HDAC1, CASP9, HSP90AA1, and HSP90AB1, which can potentially inhibit the cell cycle of mBCSCs. Moreover, our results showed that PTTH could modulate the PI3K/Akt/mTOR and HIF1/NFkB/pathways. Overall, these findings highlight the potential of HNK as an immunotherapeutic agent for mBCSCs by modulating the tumor immune environment.

Honokiol Induces Ferroptosis by Upregulating HMOX1 in Acute Myeloid Leukemia Cells

Acute myeloid leukemia (AML) is one of the malignant hematological cancers with high mortality. Finding a more effective and readily available treatment is of the utmost importance. Here, we aimed to identify the anti-leukemia effect of a natural small molecule compound honokiol on a panel of AML cell lines, including THP-1, U-937, and SKM-1, and explored honokiol’s potential biological pathways and mechanisms. The results showed that honokiol decreased the viability of the targeted AML cells, induced their cell cycle arrest at G0/G1 phase, and inhibited their colony-formation capacity. Honokiol also triggers a noncanonical ferroptosis pathway in THP-1 and U-937 cells by upregulating the level of intracellular lipid peroxide and HMOX1 significantly. Subsequent studies verified that HMOX1 was a critical target in honokiol-induced ferroptosis. These results reveal that honokiol is an effective anti-leukemia agent in AML cell lines and may be a potential ferroptosis activator in AML.

Current methods to analyze lysosome morphology, positioning, motility and function

Since the discovery of lysosomes more than 70 years ago, much has been learned about the functions of these organelles. Lysosomes were regarded as exclusively degradative organelles, but more recent research has shown that they play essential roles in several other cellular functions, such as nutrient sensing, intracellular signalling and metabolism. Methodological advances played a key part in generating our current knowledge about the biology of this multifaceted organelle. In this review, we cover current methods used to analyze lysosome morphology, positioning, motility and function. We highlight the principles behind these methods, the methodological strategies and their advantages and limitations. To extract accurate information and avoid misinterpretations, we discuss the best strategies to identify lysosomes and assess their characteristics and functions. With this review, we aim to stimulate an increase in the quantity and quality of research on lysosomes and further ground-breaking discoveries on an organelle that continues to surprise and excite cell biologists.

AKF-D52, a Synthetic Phenoxypyrimidine-Urea Derivative, Triggers Extrinsic/Intrinsic Apoptosis and Cytoprotective Autophagy in Human Non-Small Cell Lung Cancer Cells

Simple Summary

We previously reported the antiproliferative effects of a phenoxypyridine urea derivative. In this study, we aimed to investigate the antiproliferative effects of 1-(3,5-dimethoxyphenyl)-3-(4-(3-methoxyphenoxy)-2-((4-morpholinophenyl)amino)pyrimidin-5-yl)urea (AKF-D52) in non-small cell lung cancer cells. We found that (i) AKF-D52 induces apoptosis in caspase-dependent and caspase-independent pathways; (ii) AKF-D52-induced apoptosis is caused by the clustering of a death-inducing signaling complex and mitochondrial-dependent signaling; (iii) AKF-D52 induces cytoprotective autophagy, and pre-treatment with an autophagy inhibitor enhances the apoptotic effect of AKF-D52; and (iv) AKF-D52-induced apoptosis and autophagy are attenuated by the reactive oxygen species (ROS) scavenger α-tocopherol. Furthermore, AKF-D52 suppressed tumor growth in a xenograft mouse model. Collectively, our findings regarding the efficacy and molecular mechanisms of AKF-D52 identify this compound as a potential therapeutic agent for the treatment of lung cancer.

Abstract

Previously, we discovered that 1-(3,5-dimethoxyphenyl)-3-(4-(3-methoxyphenoxy)-2-((4-morpholinophenyl)amino)pyrimidin-5-yl)urea (AKF-D52), a synthetic phenoxypyrimidine urea derivative, acts as a growth inhibitor of various cancer cell types. In this study, we elucidated the antiproliferative properties of AFK-D52 and underlying mechanisms in non-small cell lung cancer (NSCLC) cells and an A549 xenograft animal model. AKF-D52 was found to induce both caspase-dependent and -independent apoptotic cell death. Furthermore, the mitochondrial component of the AKF-D52-induced apoptosis mechanism involves a reduction in mitochondrial membrane potential and regulation in B cell lymphoma-2 family protein expression. Moreover, AKF-D52 activates the extrinsic pathway through up-regulated expression of death receptor 3 and Fas and then the formation of a death-inducing signaling complex. AKF-D52 also induced autophagy by increasing acidic vesicular organelle formation and microtubule-associated protein 1A/1B-light chain 3-II levels and reducing p62 levels. Notably, pretreatment with autophagy inhibitors enhanced AKF-D52-induced cell death, indicating that the induced autophagy is cytoprotective. AKF-D52 treatment also triggered reactive oxygen species (ROS) production in NSCLC cells, whereas the antioxidant α-tocopherol abolished AKF-D52-induced cell death. In a xenograft lung cancer mouse model, AKF-D52 administration attenuated tumor growth by inducing apoptosis and autophagy in tumor tissues. Collectively, our data indicate that AKF-D52-induced ROS production plays a role in mediating apoptosis and cytoprotective autophagy in NSCLC.

13R,20-Dihydroxydocosahexaenoic Acid, a Novel Dihydroxy- DHA Derivative, Inhibits Breast Cancer Stemness through Regulation of the Stat3/IL-6 Signaling Pathway by Inducing ROS Production

Breast cancer is a major health problem worldwide. Cancer stem cells (CSCs) are known to mediate breast cancer metastasis and recurrence and are therefore a promising therapeutic target. In this study, we investigated the anti-inflammatory effect of 13R,20-dihydroxydocosahexaenoic acid (13R,20-diHDHA), a novel dihydroxy-DHA derivative, which was synthesized through an enzymatic reaction using cyanobacterial lipoxygenase. We found that 13R,20-diHDHA reduced the macrophage secretion of the inflammatory cytokines, IL-6 and TNF-α, and thus appeared to have anti-inflammatory effects. As the inflammatory tumor microenvironment is largely devoted to supporting the cancer stemness of breast cancer cells, we investigated the effect of 13R,20-diHDHA on breast cancer stemness. Indeed, 13R,20-diHDHA effectively inhibited breast cancer stemness, as evidenced by its ability to dose-dependently inhibit the mammospheres formation, colony formation, migration, and invasion of breast CSCs. 13R,20-diHDHA reduced the populations of CD44^high/CD24^low and aldehyde dehydrogenase (ALDH)-positive cells and the expression levels of the cancer stemness-related self-renewal genes, Nanog, Sox2, Oct4, c-Myc, and CD44. 13R,20-diHDHA increased reactive oxygen species (ROS) production, and the generated ROS reduced the phosphorylation of nuclear signal transducer and activator of transcription 3 (Stat3) and the secretion of IL-6 by mammospheres. These data collectively suggest that 13R,20-diHDHA inhibits breast cancer stemness through ROS production and downstream regulation of Stat3/IL-6 signaling, and thus might be developed as an anti-cancer agent acting against CSCs.

Dissecting the Gene Expression Networks Associated with Variations in the Major Components of the Fatty Acid Semimembranosus Muscle Profile in Large White Heavy Pigs

Simple Summary

The amount and fatty acid composition of intramuscular fat are important features for the qualitative characteristics of processed and fresh meat products, but the knowledge of the key molecular drivers controlling these traits is still scant. To this aim, the present study investigated the co-expression networks of genes related to variations in the major fatty acids deposited in pig Semimembranosus muscle. Palmitic and palmitoleic acid contents were associated with a downregulation of genes involved in autophagy, mitochondrial fusion, and mitochondrial activity, suggesting that the deposition of these fatty acids may be enhanced in muscles with a reduced mitochondrial function. A higher proportion of oleic acid and a reduction in the percentages of n-6 and n-3 polyunsaturated fatty acids were related to changes in the mRNA levels of genes involved in Mitogen-Activated Protein Kinase (MAPK) signaling. The obtained results indicated gene expression networks and new candidate genes associated with the studied traits. Further studies are needed to confirm our results and identify in the discussed genes molecular markers for future selection schemes aimed at improving pork nutritional and technological quality. Furthermore, as pigs are considered reliable animal models for several human conditions, the obtained results may also be of interest for improving the knowledge of the molecular pathways associated with obesity and diabetes.

Abstract

To date, high-throughput technology such as RNA-sequencing has been successfully applied in livestock sciences to investigate molecular networks involved in complex traits, such as meat quality. Pork quality depends on several organoleptic, technological, and nutritional characteristics, and it is also influenced by the fatty acid (FA) composition of intramuscular fat (IMF). To explore the molecular networks associated with different IMF FA compositions, the Semimembranosus muscle (SM) from two groups of Italian Large White (ILW) heavy pigs divergent for SM IMF content was investigated using transcriptome analysis. After alignment and normalization, the obtained gene counts were used to perform the Weighted Correlation Network Analysis (WGCNA package in R environment). Palmitic and palmitoleic contents showed association with the same gene modules, comprising genes significantly enriched in autophagy, mitochondrial fusion, and mitochondrial activity. Among the key genes related to these FAs, we found TEAD4, a gene regulating mitochondrial activity that seems to be a promising candidate for further studies. On the other hand, the genes comprised in the modules associated with the IMF contents of oleic, n-6, and n-3 polyunsaturated FAs (PUFAs) were significantly enriched in Mitogen-Activated Protein Kinase (MAPK) signaling, in agreement with previous studies suggesting that several MAPK players may have a primary role in regulating lipid deposition. These results give an insight into the molecular cascade associated with different IMF FA composition in ILW heavy pigs. Further studies are needed to validate the results and confirm whether some of the identified key genes may be effective candidates for pork quality.