Quantifying the Level of 8-oxo-dG Using ELISA Assay to Evaluate Oxidative DNA Damage in MCF-7 Cells.

8-Oxo-7,8-dihydro-2'-deoxyguanosine (8-oxo-dG) base is the predominant form of commonly observed DNA oxidative damage. DNA impairment profoundly impacts gene expression and serves as a pivotal factor in stimulating neurodegenerative disorders, cancer, and aging. Therefore, precise quantification of 8-oxoG has clinical significance in the investigation of DNA damage detection methodologies. However, at present, the existing approaches for 8-oxoG detection pose challenges in terms of convenience, expediency, affordability, and heightened sensitivity. We employed the sandwich enzyme-linked immunosorbent assay (ELISA) technique, a highly efficient and swift colorimetric method, to detect variations in 8-oxo-dG content in MCF-7 cell samples stimulated with different concentrations of hydrogen peroxide (H2O2). We determined the concentration of H2O2 that induced oxidative damage in MCF-7 cells by detecting its IC50 value in MCF-7 cells. Subsequently, we treated MCF-7 cells with 0, 0.25, and 0.75 mM H2O2 for 12 h and extracted 8-oxo-dG from the cells. Finally, the samples were subjected to ELISA. Following a series of steps, including plate spreading, washing, incubation, color development, termination of the reaction, and data collection, we successfully detected changes in the 8-oxo-dG content in MCF-7 cells induced by H2O2. Through such endeavors, we aim to establish a method to evaluate the degree of DNA oxidative damage within cell samples and, in doing so, advance the development of more expedient and convenient approaches for DNA damage detection. This endeavor is poised to make a meaningful contribution to the exploration of associative analyses between DNA oxidative damage and various domains, including clinical research on diseases and the detection of toxic substances.

ARID1B maintains mesenchymal stem cell quiescence via inhibition of BCL11B-mediated non-canonical Activin signaling.

ARID1B haploinsufficiency in humans causes Coffin-Siris syndrome, associated with developmental delay, facial dysmorphism, and intellectual disability. The role of ARID1B has been widely studied in neuronal development, but whether it also regulates stem cells remains unknown. Here, we employ scRNA-seq and scATAC-seq to dissect the regulatory functions and mechanisms of ARID1B within mesenchymal stem cells (MSCs) using the mouse incisor model. We reveal that loss of Arid1b in the GLI1+ MSC lineage disturbs MSCs' quiescence and leads to their proliferation due to the ectopic activation of non-canonical Activin signaling via p-ERK. Furthermore, loss of Arid1b upregulates Bcl11b, which encodes a BAF complex subunit that modulates non-canonical Activin signaling by directly regulating the expression of activin A subunit, Inhba. Reduction of Bcl11b or non-canonical Activin signaling restores the MSC population in Arid1b mutant mice. Notably, we have identified that ARID1B suppresses Bcl11b expression via specific binding to its third intron, unveiling the direct inter-regulatory interactions among BAF subunits in MSCs. Our results demonstrate the vital role of ARID1B as an epigenetic modifier in maintaining MSC homeostasis and reveal its intricate mechanistic regulatory network in vivo, providing novel insights into the linkage between chromatin remodeling and stem cell fate determination.

Ganonorsterone A, a norsteroid from the medicinal fungus Ganoderma lingzhi.

Phytochemical investigation on the fruiting bodies of the medicinal fungus Ganoderma lingzhi led to the isolation of a new norsteroid, namely ganonorsterone A (1), together with one known steroid, cyathisterol (2). The structure and absolute configuration of compound 1 were assigned by extensive analysis of MS, NMR data, and quantum-chemical calculations including electronic circular dichroism (ECD) and calculated 13C NMR-DP4+ analysis. Bioassay results showed that compound 1 displayed moderate inhibition on NO production in RAW 264.7 macrophages.

Two way workable microchanneled hydrogel suture to diagnose, treat and monitor the infarcted heart.

During myocardial infarction, microcirculation disturbance in the ischemic area can cause necrosis and formation of fibrotic tissue, potentially leading to malignant arrhythmia and myocardial remodeling. Here, we report a microchanneled hydrogel suture for two-way signal communication, pumping drugs on demand, and cardiac repair. After myocardial infarction, our hydrogel suture monitors abnormal electrocardiogram through the mobile device and triggers nitric oxide on demand via the hydrogel sutures' microchannels, thereby inhibiting inflammation, promoting microvascular remodeling, and improving the left ventricular ejection fraction in rats and minipigs by more than 60% and 50%, respectively. This work proposes a suture for bidirectional communication that acts as a cardio-patch to repair myocardial infarction, that remotely monitors the heart, and can deliver drugs on demand.

High FAAP24 expression reveals poor prognosis and an immunosuppressive microenvironment shaping in AML.

BACKGROUND: As a core member of the FA complex, in the Fanconi anemia pathway, FAAP24 plays an important role in DNA damage repair. However, the association between FAAP24 and patient prognosis in AML and immune infiltration remains unclear. The purpose of this study was to explore its expression characteristics, immune infiltration pattern, prognostic value and biological function using TCGA-AML and to verify it in the Beat AML cohort. METHODS: In this study, we examined the expression and prognostic value of FAAP24 across cancers using data from TCGA, TARGET, GTEx, and GEPIA2. To further investigate the prognosis in AML, development and validation of a nomogram containing FAAP24 were performed. GO/KEGG, ssGSEA, GSVA and xCell were utilized to explore the functional enrichment and immunological features of FAAP24 in AML. Drug sensitivity analysis used data from the CellMiner website, and the results were confirmed in vitro. RESULTS: Integrated analysis of the TCGA, TARGET and GTEx databases showed that FAAP24 is upregulated in AML; meanwhile, high FAAP24 expression was associated with poor prognosis according to GEPIA2. Gene set enrichment analysis revealed that FAAP24 is implicated in pathways involved in DNA damage repair, the cell cycle and cancer. Components of the immune microenvironment using xCell indicate that FAAP24 shapes an immunosuppressive tumor microenvironment (TME) in AML, which helps to promote AML progression. Drug sensitivity analysis showed a significant correlation between high FAAP24 expression and chelerythrine resistance. In conclusion, FAAP24 could serve as a novel prognostic biomarker and play an immunomodulatory role in AML. CONCLUSIONS: In summary, FAAP24 is a promising prognostic biomarker in AML that requires further exploration and confirmation.

Mutation spectrum of FLT3 and significance of non-canonical FLT3 mutations in haematological malignancy.

Fms-like tyrosine kinase 3 (FLT3) is frequently mutated in haematological malignancies. Although canonical FLT3 mutations including internal tandem duplications (ITDs) and tyrosine kinase domains (TKDs) have been extensively studied, little is known about the clinical significance of non-canonical FLT3 mutations. Here, we first profiled the spectrum of FLT3 mutations in 869 consecutively newly diagnosed acute myeloid leukaemia (AML), myelodysplastic syndrome and acute lymphoblastic leukaemia patients. Our results showed four types of non-canonical FLT3 mutations depending on the affected protein structure: namely non-canonical point mutations (NCPMs) (19.2%), deletion (0.7%), frameshift (0.8%) and ITD outside the juxtamembrane domain (JMD) and TKD1 regions (0.5%). Furthermore, we found that the survival of patients with high-frequency (>1%) FLT3-NCPM in AML was comparable to those with canonical TKD. In vitro studies using seven representative FLT3-deletion or frameshift mutant constructs showed that the deletion mutants of TKD1 and the FLT3-ITD mutant of TKD2 had significantly higher kinase activity than wild-type FLT3, whereas the deletion mutants of JMD had phosphorylation levels comparable with wild-type FLT3. All tested deletion mutations and ITD were sensitive to AC220 and sorafenib. Collectively, these data enrich our understanding of FLT3 non-canonical mutations in haematological malignancies. Our results may also facilitate prognostic stratification and targeted therapy of AML with FLT3 non-canonical mutations.

BRD9-mediated chromatin remodeling suppresses osteoclastogenesis through negative feedback mechanism.

Bromodomain-containing protein 9 (BRD9), a component of non-canonical BAF chromatin remodeling complex, has been identified as a critical therapeutic target in hematological diseases. Despite the hematopoietic origin of osteoclasts, the role of BRD9 in osteoclastogenesis and bone diseases remains unresolved. Here, we show Brd9 deficiency in myeloid lineage enhances osteoclast lineage commitment and bone resorption through downregulating interferon-beta (IFN-ß) signaling with released constraint on osteoclastogenesis. Notably, we show that BRD9 interacts with transcription factor FOXP1 activating Stat1 transcription and IFN-ß signaling thereafter. Besides, function specificity of BRD9 distinguished from BRD4 during osteoclastogenesis has been evaluated. Leveraging advantages of pharmacological modulation of BRD9 and flexible injectable silk fibroin hydrogel, we design a local deliver system for effectively mitigating zoledronate related osteonecrosis of the jaw and alleviating acute bone loss in lipopolysaccharide-induced localized aggressive periodontitis. Overall, these results demonstrate the function of BRD9 in osteoclastogenesis and its therapeutic potential for bone diseases.

Comprehensive analysis of ERCC3 prognosis value and ceRNA network in AML.

BACKGROUND: Acute myeloid leukemia (AML) is a hematological malignancy with high molecular and clinical heterogeneity, and is the most common type of acute leukemia in adults. Due to limited treatment options, AML is prone to relapse and has a poor prognosis. Excision repair cross-complementing 3 (ERCC3) is an important member of nucleotide excision repair (NER) that is overexpressed in types of solid cancers and potentially regarded as a prognostic factor. However, its role in AML remains unclear. The purpose of this study was to explore ERCC3 expression and functions in AML. METHODS: The Cancer Genome Atlas (TCGA) and GEO (Gene Expression Omnibus) were used to test the accuracy of ERCC3 expression levels for AML diagnosis. Using online databases and R packages, we also explored the signaling pathway, epigenetic regulation, infiltration of immune cells, clinical prognostic value, and ceRNA network in AML. RESULTS: Our results revealed that ERCC3 expression was increased in AML and that high ERCC3 expression had good value for disease-free survival and overall survival in AML patients who underwent allogeneic hematopoietic stem cell transplantation (allo-HSCT). We found that ERCC3 and co-expressed genes were mainly involved in chemical carcinogenesis/reactive oxygen species, ubiquitin-mediated protein degradation and oxidative phosphorylation. In addition, almost all the m6A-related coding genes (except GF2BP1) were positively associated with ERCC3 expression. We also constructed a ceRNA regulatory network containing ERCC3 in AML and identified 6 pairs of ceRNA networks, indicating that ERCC3 expression is regulated by a noncoding RNA system. CONCLUSION: This study demonstrated that ERCC3 was overexpressed in AML and that high ERCC3 expression can be considered a biomarker conducive to allo-HSCT in AML patients.

MEK/ERK/RUNX2 Pathway-Mediated IL-11 Autocrine Promotes the Activation of Müller Glial Cells during Diabetic Retinopathy.

PURPOSE: To uncover the role of the mitogen-activated protein kinase kinase (MEK)/extracellular signal-regulated kinase (ERK)/runt-related transcription factor 2 (RUNX2)/interleukin-11 (IL-11) pathway in the activation of Müller glial cells (MGCs) and the breakdown of blood-retina barrier (BRB) during diabetic retinopathy (DR). METHODS: Western blot (WB) detected the activation of MEK/ERK/RUNX2/IL-11 pathway, and quantitative reverse transcription polymerase chain reaction (qRT-PCR) detected IL-11 mRNA levels in high glucose (HG)-exposed MIO-M1 cells. Co-immunoprecipitation (Co-IP) identified the interaction between ERK and RUNX2. Immunofluorescence (IF) measured the co-localization of ERK and RUNX2. Luciferase reporter gene assay identified the transcription activity of IL-11 promoter under HG conditions. Enzyme-linked immunosorbent assay (ELISA) detected IL-11 levels in MIO-M1 cell culture supernatant. WB detected IL-RA protein levels, and Immunofluorescence measured the co-localization of IL-11 and IL-11RA. WB detected MGCs activation marker glial fibrillary acidic protein (GFAP) protein levels. 5-ethynyl-2'-deoxyuridine (EdU) incorporation assay detected the proliferation of MGCs. WB detected the activation of MEK/ERK/RUNX2/IL-11 pathway in streptozotocin (STZ)-induced diabetic mice. ELISA detected IL-11 and IL-11RA levels in mouse retina tissues. QRT-PCR and WB detected tight junction-associated molecules claudin-5, occluding and tight junction protein 1 (ZO-1) mRNA and protein levels in mouse retina tissues, respectively. RESULTS: MEK/ERK/RUNX2/IL-11 pathway was activated in HG-exposed MIO-M1 cells. Additionally, IL-11 bound to IL-11RA on MIO-M1 cells to promote MIO-M1 cell activation and proliferation. In the mouse STZ-induced diabetic model, MEK/ERK/RUNX2/IL-11/IL-11RA pathway was also activated. Finally, the blockade of the pathway mitigated the activation of MGCs and the breakdown of BRB. CONCLUSION: The data suggested that activated MEK/ERK/RUNX2/IL-11/IL-11RA autocrine pathway can promote the activation of MGCs and the breakdown of BRB during DR, implying novel anti-molecular strategies for the treatment of DR.

Combination of Venetoclax and Midostaurin Efficiently Suppressed Relapsed t(8;21)Acute Myeloid Leukemia With Mutant KIT After Failure of Venetoclax Plus Azacitidine Treatment.

Acute myeloid leukemia (AML) with t(8;21) is categorized as favorable-risk AML, but KIT mutations show a significantly poor prognostic impact in such patients. Persistent vulnerability to relapse is a major challenge in the treatment of this subtype of patients. Venetoclax is a BCL-2 selective inhibitor. The venetoclax+HMA strategy is also a notable salvage regimen that achieves good clinical outcomes in the treatment of relapsed or refractory (R/R) AML. However, in our clinical practice, we found that disease progressed rapidly even after venetoclax+azacitidine (AZA) therapy in two relapsed t(8;21) AML patients with KIT mutations. We report for the first time the therapeutic potential of venetoclax+midostaurin as a new combination therapy for relapsed t(8;21) AMLs with KIT mutations showing resistance to venetoclax+AZA therapy. Our ex vivo study also showed that midostaurin alone could inhibit proliferation and induce apoptosis of Kasumi-1 cells (e.g. Midostaurin induced G2 phase cell arrest, down-regulated p-KIT and BCL-2, while Bax protein levels were up-regulated) and observed a synergistic anti effect when the two drugs were combined. Our study shows that the venetoclax+midostaurin regimen may be a promising treatment option for R/R t(8;21) AML with KIT mutations.

Building quantum mechanics quality force fields of proteins with the generalized energy-based fragmentation approach and machine learning.

We combined our generalized energy-based fragmentation (GEBF) approach and machine learning (ML) technique to construct quantum mechanics (QM) quality force fields for proteins. In our scheme, the training sets for a protein are only constructed from its small subsystems, which capture all short-range interactions in the target system. The energy of a given protein is expressed as the summation of atomic contributions from QM calculations of various subsystems, corrected by long-range Coulomb and van der Waals interactions. With the Gaussian approximation potential (GAP) method, our protocol can automatically generate training sets with high efficiency. To facilitate the construction of training sets for proteins, we store all trained subsystem data in a library. If subsystems in the library are detected in a new protein, corresponding datasets can be directly reused as a part of the training set on this new protein. With two polypeptides, 4ZNN and 1XQ8 segment, as examples, the energies and forces predicted by GEBF-GAP are in good agreement with those from conventional QM calculations, and dihedral angle distributions from GEBF-GAP molecular dynamics (MD) simulations can also well reproduce those from ab initio MD simulations. In addition, with the training set generated from GEBF-GAP, we also demonstrate that GEBF-ML force fields constructed by neural network (NN) methods can also show QM quality. Therefore, the present work provides an efficient and systematic way to build QM quality force fields for biological systems.

Arid1a-Plagl1-Hh signaling is indispensable for differentiation-associated cell cycle arrest of tooth root progenitors.

Chromatin remodelers often show broad expression patterns in multiple cell types yet can elicit cell-specific effects in development and diseases. Arid1a binds DNA and regulates gene expression during tissue development and homeostasis. However, it is unclear how Arid1a achieves its functional specificity in regulating progenitor cells. Using the tooth root as a model, we show that loss of Arid1a impairs the differentiation-associated cell cycle arrest of tooth root progenitors through Hedgehog (Hh) signaling regulation, leading to shortened roots. Our data suggest that Plagl1, as a co-factor, endows Arid1a with its cell-type/spatial functional specificity. Furthermore, we show that loss of Arid1a leads to increased expression of Arid1b, which is also indispensable for odontoblast differentiation but is not involved in regulation of Hh signaling. This study expands our knowledge of the intricate interactions among chromatin remodelers, transcription factors, and signaling molecules during progenitor cell fate determination and lineage commitment.

Arid1a regulates cell cycle exit of transit-amplifying cells by inhibiting the Aurka-Cdk1 axis in mouse incisor.

Stem cells self-renew or give rise to transit-amplifying cells (TACs) that differentiate into specific functional cell types. The fate determination of stem cells to TACs and their transition to fully differentiated progeny is precisely regulated to maintain tissue homeostasis. Arid1a, a core component of the switch/sucrose nonfermentable complex, performs epigenetic regulation of stage- and tissue-specific genes that is indispensable for stem cell homeostasis and differentiation. However, the functional mechanism of Arid1a in the fate commitment of mesenchymal stem cells (MSCs) and their progeny is not clear. Using the continuously growing adult mouse incisor model, we show that Arid1a maintains tissue homeostasis through limiting proliferation, promoting cell cycle exit and differentiation of TACs by inhibiting the Aurka-Cdk1 axis. Loss of Arid1a overactivates the Aurka-Cdk1 axis, leading to expansion of the mitotic TAC population but compromising their differentiation ability. Furthermore, the defective homeostasis after loss of Arid1a ultimately leads to reduction of the MSC population. These findings reveal the functional significance of Arid1a in regulating the fate of TACs and their interaction with MSCs to maintain tissue homeostasis.

Reciprocal interaction between mesenchymal stem cells and transit amplifying cells regulates tissue homeostasis.

Interaction between adult stem cells and their progeny is critical for tissue homeostasis and regeneration. In multiple organs, mesenchymal stem cells (MSCs) give rise to transit amplifying cells (TACs), which then differentiate into different cell types. However, whether and how MSCs interact with TACs remains unknown. Using the adult mouse incisor as a model, we present in vivo evidence that TACs and MSCs have distinct genetic programs and engage in reciprocal signaling cross talk to maintain tissue homeostasis. Specifically, an IGF-WNT signaling cascade is involved in the feedforward from MSCs to TACs. TACs are regulated by tissue-autonomous canonical WNT signaling and can feedback to MSCs and regulate MSC maintenance via Wnt5a/Ror2-mediated non-canonical WNT signaling. Collectively, these findings highlight the importance of coordinated bidirectional signaling interaction between MSCs and TACs in instructing mesenchymal tissue homeostasis, and the mechanisms identified here have important implications for MSC-TAC interaction in other organs.

miR-519d-3p Overexpression Inhibits P38 and PI3K/AKT Pathway via Targeting VEGFA to Attenuate the Malignant Biological Behavior of Non-Small Cell Lung Cancer.

BACKGROUND: Non-small cell lung cancer (NSCLC) is a heterogeneous tumor that accounts for approximately 85% of all lung cancer cases worldwide. microRNAs (miRNAs) are believed to play an important role in regulating a variety of biological processes, including immunity and cancer. We investigated the effect of miR-519d-3p on the mitigation of NSCLC in vitro and in vivo. METHODS: RT-PCR or immunohistochemical assays were used to assess the expression of miR-519d-3p. Colony formation, flow cytometry, and transwell assay were respectively used to detect proliferation, apoptosis, and invasion of A549 and NCI-H661 cell lines. Luciferase reporter assay was used to verify targeting the relationship between mir-519d-3p and VEGFA. Western blot was used to examine the expression of Ki67, caspase-3, E-cadherin, N-cadherin, VEGF, P38, and PI3K/AKT. Animal models were established by BABL/c mice to research the effect of mir-519d-3p overexpression in vivo. RESULTS: In vitro, miR-519d-3p overexpression inhibited A549 and NCI-H661 cells proliferation, invasion, and also promoted apoptosis. In addition, miR-519d-3p overexpression downregulated VEGFA expression and decreased the P38 and PI3K/AKT phosphorylation level. In vivo, miR-519d-3p overexpression significantly restrained tumor volume (2087±265 mm3 vs 599±135 mm3, *P< 0.05) and tumor weight (0.45±0.08 g vs 0.13±0.06 g, *P<0.05) compared with the control group. Overexpression of miR-519d-3p downregulated levels of Ki67 and N-cadherin significantly. CONCLUSION: The data indicated that miR-519d-3p could be a novel therapy or adjuvant against NSCLC.

The Analysis of the Anti-Tumor Mechanism of Ursolic Acid Using Connectively Map Approach in Breast Cancer Cells Line MCF-7.

BACKGROUND: Ursolic acid (UA), a primary bioactive triterpenoid, was reported as an anti-cancer agent. However, the current knowledge of UA and its potential anti-cancer mechanisms and targets in breast cancer cells are limited. In this study, we aimed to illustrate the potential mechanisms and targets of UA in breast cancer cells MCF-7. METHODS: The effect of UA on cell growth was determined in MCF-7 cells by MTT assay. The anti-tumor mechanism of UA was evaluated by microarray, CAMP, and Western blot. Moreover, the molecular docking between UA and potential receptors were predicted by iGEMDOCK software. RESULTS: The result of MTT assay demonstrated that UA could inhibit MCF-7 cell growth with IC50 values of 20 µM. Microarray and CMAP analysis, validated by Western blot, indicated that UA significantly modulated IKK/NF-κB, RAF/ERK pathways, and down-regulated the phosphorylation level of PLK1 in MCF-7 cells. CONCLUSION: Our data indicated that the anti-tumor effects of UA are due to the inhibited RAF/ERK pathway and IKK/NF-κB pathway. It could also be explained by the reduced phosphorylation of PLK1 in MCF-7 cells. This study provides a new insight for deep understanding of the new anti-cancer mechanisms of UA in MCF-7 breast cancer cells.

A novel positive feedback loop of linc02042 and c-Myc mediated by YBX1 promotes tumorigenesis and metastasis in esophageal squamous cell carcinoma.

BACKGROUND: Long non-coding RNA (lncRNA) is a class of endogenous RNA with a length of more than 200 nucleotides, which is emerging as a pivotal player in cancer development and progression. However, the functional roles of many members in this class remain largely uncharacterized. In the present study, we explored the biological relevance of linc02042 in esophageal squamous cell carcinoma (ESCC). METHODS: qRT-PCR was used to detect the levels of linc02042 and c-Myc. Western blot was used to assess protein expression level. CCK-8 and Transwell assays were employed to test ESCC cell proliferation and invasion, respectively. The mice study including xenograft tumor and lung metastasis models was used to determine the role of linc02042 in vivo. RNA pull-down, ChIP and luciferase reporter assays were employed to test the relationship between linc02042, YBX1 and c-Myc. RESULTS: Linc02042 was found to be markedly upregulated in ESCC cell lines, tissues and plasma, and was closely correlated with malignant clinical features. Knockdown of linc02042 significantly inhibited ESCC cell viability and invasion in vitro as well as tumor growth and lung metastasis in vivo, whereas overexpression of linc02042 resulted in the opposite results. Mechanistically, linc02042 acted as a scaffold for YBX-1 binding to the 3'-UTR of c-Myc mRNA, leading to enhanced c-Myc mRNA stability, thereby facilitating ESCC growth and metastasis. Moreover, in turn, c-Myc was able to transcriptionally elevate linc02042 by directly binding to the E-box motif proximal to the transcription start site (TSS) of linc02042 promoter. Clinically, linc02042 was identified as an effective diagnostic and prognostic biomarker for ESCC patients, and its expression was strongly positively correlated with c-Myc expression in ESCC tissues. CONCLUSION: Our data suggest that linc02042 plays an important tumor-promoting role in ESCC, which lays a foundation for considering it as a potential target for ESCC patients.

FEN1 inhibitor increases sensitivity of radiotherapy in cervical cancer cells.

BACKGROUND: Cervical cancer is one of the most common causes of cancer-associated mortality among affected women in the world. At present, treatment with weekly cisplatin plus ionizing radiation (IR) therapy is the standard regimen for cervical cancer, especially for locally advanced cervical cancer. The purpose of this study is to determine whether FEN1 inhibitors could enhance the therapeutic effect of IR therapy. METHODS: Western blot was applied to determine the expression of FEN1- and apoptosis-related proteins. Cell growth inhibition assay and colony formation assay were used to determine the effects of FEN1 inhibitor and IR exposure for Hela cells in vitro. CRISPR technology was used to knockdown FEN1 expression level of 293T cells, and tumor xenograft in nude mice was employed to determine the effects of FEN1 inhibitor and IR exposure on tumor growth in vivo. RESULTS: Our data revealed that FEN1 is overexpressed in HeLa cell and can be upregulated further by IR. We also demonstrated that FEN1 inhibitor enhances IR sensitivity of cervical cancer in vitro and in vivo. CONCLUSION: FEN1 inhibitor SC13 could sensitize radiotherapy of cervical cancer cell.