Evaluation of nintedanib efficacy: Attenuating the lens fibrosis in vitro and vivo.

PURPOSE: Organ fibrosis is a huge challenge in clinic. There are no drugs for fibrotic cataracts treatments in clinic. Nintedanib is approved by the FDA for pulmonary fibrosis treatments. This study aims to investigate the efficacy and mechanism of nintedanib on fibrotic cataracts. METHODS: Drug efficacy was validated through TGFß2-induced cell models and injury-induced anterior subcapsular cataract (ASC) mice. A slit lamp and the eosin staining technique were applied to access the degree of capsular fibrosis. The CCK-8 assay was used to evaluate the toxicity and anti-proliferation ability of the drug. The cell migration was determined by wound healing assay and transwell assay. The anti-epithelial mesenchymal transition (EMT) and anti-fibrosis efficacy were evaluated by qRT-PCR, immunoblot, and immunofluorescence. The inhibition of nintedanib to signaling pathways was certified by immunoblot. RESULTS: Nintedanib inhibited the migration and proliferation of TGFß2-induced cell models. Nintedanib can also repress the EMT and fibrosis of the lens epithelial cells. The intracameral injection of nintedanib can also allay the anterior subcapsular opacification in ASC mice. The TGFß2/ Smad and non-Smad signaling pathways can be blocked by nintedanib in vitro and in vivo. CONCLUSION: Nintedanib alleviates fibrotic cataracts by suppressing the TGFß2/ Smad and non-Smad signaling pathways. Nintedanib is a potential drug for lens fibrosis.

Effect of TEMPO-oxidized bacterial cellulose nanofibers stabilized Pickering emulsion of cinnamon essential oil on structure and properties of gelatin composite films.

Pure gelatin film often exhibits high hydrophilicity and a lack of antibacterial activity, hindering its practical application in the field of food preservation. To address these issues, we incorporated 2,2,6,6-tetramethylpiperidine-1-oxyl radical (TEMPO)-oxidized bacterial cellulose (TOBC) nanofibers stabilized cinnamon essential oil (CEO) Pickering emulsions into the gelatin matrix to develop active food packaging films. The study revealed that the good distribution of emulsion droplets in the film matrix. While with increasing Pickering emulsion proportion, the microstructures of composite films were more heterogeneous, showing some pores or cavities. In addition, the insertion of TOBC-stabilized CEO emulsions could improve the elongation at break (EAB), water-resistance, UV blocking ability, and antibacterial activity of film, but reduced its tensile strength (TS) and water vapor barrier properties (WVP). Notably, the film prepared with 4 % TOBC-stabilized CEO Pickering emulsion demonstrated enhanced preservation of strawberries. Overall, the as-prepared gelatin-based active composite films have considerable potential for food packaging.

Corrigendum: Inhibition of O-GlcNAc transferase sensitizes prostate cancer cells to docetaxel.

[This corrects the article DOI: 10.3389/fonc.2022.993243.].

[Corrigendum] METTL3 antagonizes 5­FU chemotherapy and confers drug resistance in colorectal carcinoma.

Subsequently to the publication of the above article, the authors alerted us to the fact that the data shown in Fig. 8I (for the 'Sh­CN / 0' panel) on p. 11 were mistakenly selected from those data belonging to the experiments shown in Fig. 7H (the 'Sh­CN / 0' panel) of this paper during the final assembly of the figures for review. Note that this error did not affect the conclusions reported in this paper, as both Fig. 7H ('Sh­CN / 0') and Fig. 8I ('Sh­CN / 0') show negative controls of the Comet assay, with no obvious trailing. The revised version of Fig. 8, showing the correct data for the 'Sh­CN / 0' panel in Fig. 8I, is shown on the next page. The authors are grateful to the Editor of International Journal of Oncology for allowing them this opportunity to publish a Corrigendum, and all the authors agree with its publication. Furthermore, the authors apologize to the readership for any inconvenience caused. [International Journal of Oncology 61: 106, 2022; DOI: 10.3892/ijo.2022.5396].

Inhibition of O-GlcNAc transferase sensitizes prostate cancer cells to docetaxel.

The expression of O-GlcNAc transferase (OGT) and its catalytic product, O-GlcNAcylation (O-GlcNAc), are elevated in many types of cancers, including prostate cancer (PC). Inhibition of OGT serves as a potential strategy for PC treatment alone or combinational therapy. PC is the second common cancer type in male worldwide, for which chemotherapy is still the first-line treatment. However, the function of inhibition of OGT on chemotherapeutic response in PC cells is still unknown. In this study, we show that inhibition of OGT by genetic knockdown using shRNA or by chemical inhibition using OGT inhibitors sensitize PC cells to docetaxel, which is the most common chemotherapeutic agent in PC chemotherapy. Furthermore, we identified that microRNA-140 (miR-140) directly binds to OGT mRNA 3' untranslated region and inhibits OGT expression. Moreover, docetaxel treatment stimulates miR-140 expression, whereas represses OGT expression in PC cells. Overexpression of miR-140 enhanced the drug sensitivity of PC cells to docetaxel, which could be reversed by overexpression of OGT. Overall, this study demonstrates miR-140/OGT axis as therapeutic target in PC treatment and provides a promising adjuvant therapeutic strategy for PC therapy.

METTL3 antagonizes 5­FU chemotherapy and confers drug resistance in colorectal carcinoma.

Colorectal cancer (CRC) is one of top five leading causes of cancer­associated mortalities worldwide. 5­Fluorouracil (5­FU) is the first­line chemotherapeutic drug in the treatment of CRC; however, its antineoplastic efficiency is limited due to acquired drug resistance. The regulatory mechanism underlying 5­FU chemotherapeutic response and drug resistance in CRC remains largely unknown. The present study identified that silencing of methyltransferase­like 3 (METTL3) suppressed the proliferation and migration of CRC HCT­8 cells. Using cell survival assays, flow cytometric and colony formation analyses, it was revealed that inhibition of METTL3 sensitized HCT­8 cells to 5­FU by enhancing DNA damage and inducing apoptosis in HCT­8 cells under 5­FU treatment. Furthermore, the expression of METTL3 was upregulated in 5­FU­resistant CRC cells (HCT­8R), which contributed to drug resistance through regulation of RAD51 associated Protein 1 (RAD51AP1) expression. Western blotting, immunofluorescence staining and drug sensitivity assays demonstrated that knockdown of METTL3 augmented 5­FU­induced DNA damage and overcame 5­FU­resistance in HCT­8R cells, which could be mimicked by inhibition of RAD51AP1. The present study revealed that the METTL3/RAD51AP1 axis plays an important role in the acquisition of 5­FU resistance in CRC, and targeting METTL3/RAD51AP1 may be a promising adjuvant therapeutic strategy for patients with CRC, particularly for those with 5­FU­resistant CRC.

METTL3 promotes homologous recombination repair and modulates chemotherapeutic response in breast cancer by regulating the EGF/RAD51 axis.

Methyltransferase-like 3 (METTL3) and N6-methyladenosine (m6A) are involved in many types of biological and pathological processes, including DNA repair. However, the function and mechanism of METTL3 in DNA repair and chemotherapeutic response remain largely unknown. In present study, we identified that METTL3 participates in the regulation of homologous recombination repair (HR), which further influences chemotherapeutic response in both MCF-7 and MDA-MB-231 breast cancer (BC) cells. Knockdown of METTL3 sensitized these BC cells to Adriamycin (ADR; also named as doxorubicin) treatment and increased accumulation of DNA damage. Mechanically, we demonstrated that inhibition of METTL3 impaired HR efficiency and increased ADR-induced DNA damage by regulating m6A modification of EGF/RAD51 axis. METTL3 promoted EGF expression through m6A modification, which further upregulated RAD51 expression, resulting in enhanced HR activity. We further demonstrated that the m6A 'reader,' YTHDC1, bound to the m6A modified EGF transcript and promoted EGF synthesis, which enhanced HR and cell survival during ADR treatment in BC. Our findings reveal a pivotal mechanism of METTL3-mediated HR and chemotherapeutic drug response, which may contribute to cancer therapy.

Targeting the DNA damage response enhances CD70 CAR-T cell therapy for renal carcinoma by activating the cGAS-STING pathway.

Chimeric antigen receptor T-cell (CAR-T) therapy has shown tremendous success in eradicating hematologic malignancies. However, this success has not yet been extrapolated to solid tumors due to the limited infiltration and persistence of CAR-T cells in the tumor microenvironment (TME). In this study, we screened a novel anti-CD70 scFv and generated CD70 CAR-T cells that showed effective antitumor functions against CD70+ renal carcinoma cells (RCCs) both in vitro and in vivo. We further evaluated the effect and explored the molecular mechanism of a PARP inhibitor (PARPi) in CAR-T cell immunotherapy by administering the PARPi to mouse xenografts model derived from human RCC cells. Treatment with the PARPi promoted CAR-T cell infiltration by stimulating a chemokine milieu that promoted CAR-T cell recruitment and the modulation of immunosuppression in the TME. Moreover, our data demonstrate that PARPi modulates the TME by activating the cGAS-STING pathway, thereby altering the balance of immunostimulatory signaling and enabling low-dose CAR-T cell treatment to induce effective tumor regression. These data demonstrate the application of CD70 CAR-T cell therapeutic strategies for RCC and the cross-talk between targeting DNA damage responses and antitumor CAR-T cell therapy. These findings provide insight into the mechanisms of PARPis in CAR-T cell therapy for RCC and suggest a promising adjuvant therapeutic strategy for CAR-T cell therapy in solid tumors.

Small-molecule inhibition of APE1 induces apoptosis, pyroptosis, and necroptosis in non-small cell lung cancer.

Apurinic/apyrimidinic endonuclease 1 (APE1) plays a critical role in the base excision repair (BER) pathway, which is responsible for the excision of apurinic sites (AP sites). In non-small cell lung cancer (NSCLC), APE1 is highly expressed and associated with poor patient prognosis. The suppression of APE1 could lead to the accumulation of unrepaired DNA damage in cells. Therefore, APE1 is viewed as an important marker of malignant tumors and could serve as a potent target for the development of antitumor drugs. In this study, we performed a high-throughput virtual screening of a small-molecule library using the three-dimensional structure of APE1 protein. Using the AP site cleavage assay and a cell survival assay, we identified a small molecular compound, NO.0449-0145, to act as an APE1 inhibitor. Treatment with NO.0449-0145 induced DNA damage, apoptosis, pyroptosis, and necroptosis in the NSCLC cell lines A549 and NCI-H460. This inhibitor was also able to impede cancer progression in an NCI-H460 mouse model. Moreover, NO.0449-0145 overcame both cisplatin- and erlotinib-resistance in NSCLC cell lines. These findings underscore the importance of APE1 as a therapeutic target in NSCLC and offer a paradigm for the development of small-molecule drugs that target key DNA repair proteins for the treatment of NSCLC and other cancers.

DNA polymerase beta modulates cancer progression via enhancing CDH13 expression by promoter demethylation.

DNA polymerase ß (Pol ß) plays a critical role in DNA base excision repair (BER), which is involved in maintaining genomic stability and in the modulation of DNA demethylation. Numerous studies implicated deficiency of Pol ß in the genomic instability and dysregulation of genes expression, leading to affecting initiation of cancer. However, the role of Pol ß in cancer progression is still unclear. Here, we show that Pol ß depresses migratory and invasive capabilities of both breast and lung carcinomas, which were evident in human breast and lung cancer cells, as well as in mouse xenograft tumors. On the molecular basis, overexpression of Pol ß enhanced expression of CDH13, which show function on cell adhesion and migration. Knockdown of CDH13 restores the migratory, invasive capabilities and angiogenesis in tumor, which gets impaired by Pol ß. According to the function of BER on modulation of DNA demethylation, our studies on CDH13 expression and the DNA methylation levels of CDH13 promoter suggested that Pol ß promotes expression of CDH13 by augmenting DNA demethylation of CDH13 promoter. Our findings elucidated a novel possibility that Pol ß impair cancer cell metastasis during cancer progression and shed light on the role of Pol ß in cancer therapy.

Dysregulation of microRNA-125a contributes to obesity-associated insulin resistance and dysregulates lipid metabolism in mice.

Obesity is associated with an increased risk of developing insulin resistance (IR) and type 2 diabetes (T2D). A diverse group of factors including miRNA has been implicated in the pathogenesis of these two metabolic conditions, although underlying molecular mechanisms involved are not well defined. Here, we provide evidence that hepatic miR-125a levels are diminished in both genetic as well as dietary mouse models of obesity. Overexpression of miR-125a enhanced insulin signaling and attenuated cellular lipid accumulation in HepG2 cells and Hepa1-6 cells. Likewise, treatment of mice with ago-miR-125a increased insulin sensitivity, similar to overexpression of miR-125a, whereas treatment of mice with antago-miR-125a blunted the insulin sensitivity. Furthermore, overexpression of miR-125a in mice previously fed a high-fat diet (HFD), significantly improved insulin sensitivity, and attenuated obesity-linked hepatic steatosis and hepatocyte lipid accumulation. In addition, we show that ELOVL fatty acid elongase 6 (Elovl6) is a direct target of miR-125a, and participates in miR-125a mediated regulation of insulin sensitivity and lipid metabolism. These data led us to conclude that dysregulated miR-125a expression augments the development of obesity-induced IR and that miR-125a might serve as a therapeutic target for the development of new drug(s) in the clinical management of metabolic diseases.

Enhanced Activity of Variant DNA Polymerase ß (D160G) Contributes to Cisplatin Therapy by Impeding the Efficiency of NER.

Cisplatin, commonly used in a variety of cancer treatments, induces apoptosis in cancer cells by causing lethal DNA damage. Several DNA repair pathways participate in regulation of cisplatin treatment, leading to cisplatin sensitivity or resistance in cancer cells. DNA polymerase ß (pol ß), a key protein involved in base excision repair, confers a response to cisplatin therapy that is dependent on polymerase activity. Pol ß D160G mutation with enhanced polymerase activity, previously identified in clear cell renal cell carcinoma, enhances the sensitivity of human cancer cells and mouse xenografts to cisplatin by limiting the efficiency of nucleotide excision repair (NER). Notably, the D160G mutation impedes the recruitment of XPA to cisplatin-induced sites of DNA damage, leading to unrepaired damage and further inducing cell death. Molecular architecture analysis indicated that the D160G mutation alters protein-DNA interactions and the surface electrostatic properties of the DNA-binding regions, resulting in greater DNA affinity and polymerase activity compared with wild-type pol ß. Collectively, these results indicate that enhancing pol ß activity impedes the efficiency of NER and provide a promising adjuvant therapeutic strategy for cisplatin chemotherapy. IMPLICATIONS: Our studies demonstrate that polß D160G mutation with enhanced polymerase activity impedes NER efficiency during the repair of cisplatin-induced DNA damage, leading to increased cisplatin sensitivity in cancer cells.