Enhanced lipid biosynthesis in oral squamous cell carcinoma cancer-associated fibroblasts contributes to tumor progression: Role of IL8/AKT/p-ACLY axis.

Lipid metabolic reprogramming of tumor cells has been proven to play a critical role in tumor initiation and development. However, lipid metabolism in cancer-associated fibroblasts (CAFs) has rarely been studied, particularly in CAFs of oral squamous cell carcinoma (OSCC). Additionally, the molecular mechanism by which tumor cells regulate lipid metabolism in fibroblasts is unclear. In this study, we found that phosphorylated ATP citrate lyase (p-ACLY), a key lipid metabolic enzyme, was upregulated in OSCC CAFs. Compared to paracancerous normal fibroblasts, CAFs showed enhanced lipid synthesis, such as elevated cytosolic acetyl-CoA level and accumulation of lipid droplets. Conversely, reduction of p-ACLY level blocked this biological process. In addition, blocking lipid synthesis in CAFs or inhibiting fatty acid uptake by OSCC cells reduced the promotive effects of CAFs on OSCC cell proliferation, invasion, and migration. These findings suggested that CAFs are one of lipid sources required for OSCC progression. Mechanistically, AKT signaling activation was involved in the upregulation of p-ACLY level and lipid synthesis in CAFs. Interleukin-8 (IL8), an exocrine cytokine of OSCC cells, could activate AKT and then phosphorylate ACLY in fibroblasts. This study suggested that the IL8/AKT/p-ACLY axis could be considered as a potential target for OSCC treatment.

Mitophagy-Mediated Tumor Dormancy Protects Cancer Cells from Chemotherapy.

Despite obvious tumor shrinkage, relapse after chemotherapy remains a main cause of cancer-related mortality, indicating that a subpopulation of cancer cells acquires chemoresistance and lingers after treatment. However, the mechanism involved in the emergence of chemoresistant cells remains largely unknown. Here, we demonstrate that the degradation of mitochondria via autophagy leads to a dormant state in a subpopulation of cancer cells and confers on them resistance to lethal cisplatin (DDP) exposure. The surviving DDP-resistant cells (hereafter, DRCs) have a lower metabolic rate but a stronger potential malignant potential. In the absence of DDP, these DRCs exhibit an ever-increasing self-renewal ability and heightened tumorigenicity. The combination of chloroquine and DDP exerts potent tumor-suppressive effects. In summary, our findings illuminate the mechanism between mitophagy and tumor dormancy and prove that targeting mitophagy might be a promising approach for overcoming chemoresistance in head and neck squamous cell carcinoma (HNSCC).

FNIII14 Peptide-Enriched Membrane Nanocarrier to Disrupt Stromal Barriers through Reversing CAFs for Augmenting Drug Penetration in Tumors.

Given the key roles of cancer associated fibroblasts (CAFs) in shaping tumor stroma, this study shows a CAF-associated ITGB1-inactivating peptide-enriched membrane nanodelivery system (designated as PMNPs-D) to simultaneously target CAFs and tumor cells for boosted chemotherapy through promoted drug perfusion. In the structure of PMNPs-D, the PLGA-based inner core is loaded with the chemotherapeutic drug doxorubicin, and the outer surface is cloaked by hybrid biomembranes with the insertion of integrin ß1 (ITGB1) inhibiting peptide (i.e., FNIII14). After prolonged blood circulation and actively targeting in tumor sites, PMNPs-D can respond to CAF-overexpressed fibroblast activation protein-α (FAP-α) to trigger the release of FNIII14, which will bind to ITGB1 and inhibit CAFs' biological function in producing the stromal matrix, thereby loosening the condensed stromal structure and enhancing the permeability of nanotherapeutics in tumors. As a result, this tailor-designed nanosystem shows substantial tumor inhibition and metastasis retardation in aggressive adenoid cystic carcinoma (ACC) tumor-harboring mice.

Resistance of Acta2R149C/+ mice to aortic disease is associated with defective release of mutant smooth muscle α-actin from the chaperonin-containing TCP1 folding complex.

Pathogenic variants of the gene for smooth muscle α-actin (ACTA2), which encodes smooth muscle (SM) α-actin, predispose to heritable thoracic aortic disease. The ACTA2 variant p.Arg149Cys (R149C) is the most common alteration; however, only 60% of carriers have a dissection or undergo repair of an aneurysm by 70 years of age. A mouse model of ACTA2 p.Arg149Cys was generated using CRISPR/Cas9 technology to determine the etiology of reduced penetrance. Acta2R149C/+ mice had significantly decreased aortic contraction compared with WT mice but did not form aortic aneurysms or dissections when followed to 24 months, even when hypertension was induced. In vitro motility assays found decreased interaction of mutant SM α-actin filaments with SM myosin. Polymerization studies using total internal reflection fluorescence microscopy showed enhanced nucleation of mutant SM α-actin by formin, which correlated with disorganized and reduced SM α-actin filaments in Acta2R149C/+ smooth muscle cells (SMCs). However, the most prominent molecular defect was the increased retention of mutant SM α-actin in the chaperonin-containing t-complex polypeptide folding complex, which was associated with reduced levels of mutant compared with WT SM α-actin in Acta2R149C/+ SMCs. These data indicate that Acta2R149C/+ mice do not develop thoracic aortic disease despite decreased contraction of aortic segments and disrupted SM α-actin filament formation and function in Acta2R149C/+ SMCs. Enhanced binding of mutant SM α-actin to chaperonin-containing t-complex polypeptide decreases the mutant actin versus WT monomer levels in Acta2R149C/+ SMCs, thus minimizing the effect of the mutation on SMC function and potentially preventing aortic disease in the Acta2R149C/+ mice.

Potential targets identified in adenoid cystic carcinoma point out new directions for further research.

Adenoid cystic carcinoma (AdCC) of the head and neck originates from salivary glands, with high risks of recurrence and metastasis that account for the poor prognosis of patients. The purpose of this research was to identify key genes related to AdCC for further investigation of their diagnostic and prognostic significance. In our study, the AdCC sample datasets GSE36820, GSE59702 and GSE88804 from the Gene Expression Omnibus (GEO) database were used to explore the abnormal coexpression of genes in AdCC compared with their expression in normal tissue. A total of 115 DEGs were obtained by screening with GEO2R and FunRich software. According to functional annotation analysis using Enrichr, these DEGs were mainly enriched in the SOX2, AR, SMAD and MAPK signaling pathways. A protein-protein network of the DEGs was established by the Search Tool for the Retrieval of Interacting Genes (STRING) and annotated through the WEB-based Gene SeT AnaLysis Toolkit (WebGestalt) and was shown to be enriched with proteins involved in cardiac muscle cell proliferation and extracellular matrix organization. A Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that ITGA9, LAMB1 and BAMBI were associated with the PI3K-Akt and TGF-ß pathways. Furthermore, 36 potential target miRNAs were identified by the OncomiR and miRNA Pathway Dictionary Database (miRPathDB). In conclusion, SLC22A3, FOXP2, Cdc42EP3, COL27A1, DUSP1 and HSPB8 played critical roles according to the enrichment analysis; ITGA9, LAMB1 and BAMBI were involved in significant pathways according to the KEGG analysis; ST3Gal4 is a pivotal component of the PPI network of all the DEGs obtained; SPARC, COL4A2 and PRELP were highly related to multiple malignancies in pan-cancer research; hsa-miR-29-3p, hsa-miR-132-3p and hsa-miR-708-5p were potential regulators in AdCC. The involved pathways, biological processes and miRNAs have been shown to play significant roles in the genesis, growth, invasion and metastasis of AdCC. In this study, these identified DEGs were considered to have a potential influence on AdCC but have not been studied in this disease. The analysis results promote our understanding of the molecular mechanisms and biological processes of AdCC, which might be useful for targeted therapy or diagnosis.

Similar Biophysical Abnormalities in Glomeruli and Podocytes from Two Distinct Models.

Background FSGS is a pattern of podocyte injury that leads to loss of glomerular function. Podocytes support other podocytes and glomerular capillary structure, oppose hemodynamic forces, form the slit diaphragm, and have mechanical properties that permit these functions. However, the biophysical characteristics of glomeruli and podocytes in disease remain unclear.Methods Using microindentation, atomic force microscopy, immunofluorescence microscopy, quantitative RT-PCR, and a three-dimensional collagen gel contraction assay, we studied the biophysical and structural properties of glomeruli and podocytes in chronic (Tg26 mice [HIV protein expression]) and acute (protamine administration [cytoskeletal rearrangement]) models of podocyte injury.Results Compared with wild-type glomeruli, Tg26 glomeruli became progressively more deformable with disease progression, despite increased collagen content. Tg26 podocytes had disordered cytoskeletons, markedly abnormal focal adhesions, and weaker adhesion; they failed to respond to mechanical signals and exerted minimal traction force in three-dimensional collagen gels. Protamine treatment had similar but milder effects on glomeruli and podocytes.Conclusions Reduced structural integrity of Tg26 podocytes causes increased deformability of glomerular capillaries and limits the ability of capillaries to counter hemodynamic force, possibly leading to further podocyte injury. Loss of normal podocyte mechanical integrity could injure neighboring podocytes due to the absence of normal biophysical signals required for podocyte maintenance. The severe defects in podocyte mechanical behavior in the Tg26 model may explain why Tg26 glomeruli soften progressively, despite increased collagen deposition, and may be the basis for the rapid course of glomerular diseases associated with severe podocyte injury. In milder injury (protamine), similar processes occur but over a longer time.

Vascular disease-causing mutation, smooth muscle α-actin R258C, dominantly suppresses functions of α-actin in human patient fibroblasts.

The most common genetic alterations for familial thoracic aortic aneurysms and dissections (TAAD) are missense mutations in vascular smooth muscle (SM) α-actin encoded by ACTA2 We focus here on ACTA2-R258C, a recurrent mutation associated with early onset of TAAD and occlusive moyamoya-like cerebrovascular disease. Recent biochemical results with SM α-actin-R258C predicted that this variant will compromise multiple actin-dependent functions in intact cells and tissues, but a model system to measure R258C-induced effects was lacking. We describe the development of an approach to interrogate functional consequences of actin mutations in affected patient-derived cells. Primary dermal fibroblasts from R258C patients exhibited increased proliferative capacity compared with controls, consistent with inhibition of growth suppression attributed to SM α-actin. Telomerase-immortalized lines of control and R258C human dermal fibroblasts were established and SM α-actin expression induced with adenovirus encoding myocardin-related transcription factor A, a potent coactivator of ACTA2 Two-dimensional Western blotting confirmed induction of both wild-type and mutant SM α-actin in heterozygous ACTA2-R258C cells. Expression of mutant SM α-actin in heterozygous ACTA2-R258C fibroblasts abrogated the significant effects of SM α-actin induction on formation of stress fibers and focal adhesions, filamentous to soluble actin ratio, matrix contraction, and cell migration. These results demonstrate that R258C dominantly disrupts cytoskeletal functions attributed to SM α-actin in fibroblasts and are consistent with deficiencies in multiple cytoskeletal functions. Thus, cellular defects due to this ACTA2 mutation in both aortic smooth muscle cells and adventitial fibroblasts may contribute to development of TAAD and proliferative occlusive vascular disease.

SHIP2 controls PtdIns(3,4,5)P(3) levels and PKB activity in response to oxidative stress.

Reactive oxygen species (ROS) are known to be involved in redox signalling pathways that may contribute to normal cell function as well as disease progression. The tumour suppressor PTEN and the inositol 5-phosphatase SHIP2 are critical enzymes in the control of PtdIns(3,4,5)P(3) level. It has been reported that oxidants, including those produced in cells such as macrophages, can activate downstream signalling via the inactivation of PTEN. The present study evaluates the potential impact of SHIP2 on phosphoinositides in cells exposed to sodium peroxide. We used a model of SHIP2 deficient mouse embryonic fibroblasts (MEFs) stimulated by H(2)O(2): at 15 min, PtdIns(3,4,5)P(3) was markedly increased in SHIP2 -/- cells as compared to +/+ cells. In contrast, no significant increase in PtdIns(3,4)P(2) could be detected at 15 or 120 min incubation of the cells with H(2)O(2) (0.6 mM). PKB activity was also upregulated in SHIP2 -/- cells as compared to +/+ cells in response to H(2)O(2). SHIP2 add back experiments in SHIP2 -/- cells confirm its critical role as a lipid phosphatase in the control of PtdIns(3,4,5)P(3) level in response to H(2)O(2). We conclude that SHIP2 lipid phosphatase activity plays an important role in the metabolism PtdIns(3,4,5)P(3) which is demonstrated in oxygen stressed cells.