Human Cervical Squamous Cell Carcinoma Research Articles

N6-methyladenosine methylation on FSCN1 mediated by METTL14/IGF2BP3 contributes to human papillomavirus type 16-infected cervical squamous cell carcinoma.

Human papillomavirus (HPV) infection has been reported to be associated with N6-methyladenosine (m6A) modification in cancers. However, the underlying mechanism by which m6A methylation participates in HPV-related cervical squamous cell carcinoma (CSCC) remains largely unclear. In this study, we observed that m6A regulators methyltransferase like protein (METTL14) and insulin like growth factor 2 mRNA binding protein 3 (IGF2BP3) were upregulated in HPV-positive CSCC tissues and cell lines, and their high expression predicted poor prognosis for HPV-infected CSCC patients. Cellular functional experiments verified that HPV16 oncogenes E6/E7 upregulated the expression of METTL14 and IGF2BP3 to promote cell proliferation and epithelial mesenchymal transition of CSCC cells. Next, we found that E6/E7 stabilized fascin actin-bundling protein 1 (FSCN1) mRNA and elevated FSCN1 expression in CSCC cells through upregulating METTL14/IGF2BP3-mediated m6A modification, and FSCN1 expression was also validated to be positively associated with worse outcomes of HPV-positive CSCC patients. Finally, HPV16-positive CSCC cell lines SiHa and CaSki were transfected with knockdown vector for E6/E7 or METTL14/IGF2BP3 and overexpressing vector for FSCN1, and functional verification experiments were performed through using MTT assay, flow cytometry, wound healing assay and tumour formation assay. Results indicated that knockdown of E6/E7 or METTL14/IGF2BP3 suppressed cell proliferation, migration and tumorigenesis, and accelerated cell apoptosis of HPV-positive CSCC cells. Their tumour-suppressive effects were abolished through overexpressing FSCN1. Overall, HPV E6/E7 advanced CSCC development through upregulating METTL14/IGF2BP3-mediated FSCN1 m6A modification.

Design and synthesis of novel imidazole-chalcone derivatives as microtubule protein polymerization inhibitors to treat cervical cancer and reverse cisplatin resistance

Using the licochalcone moiety as a lead compound scaffold, 16 novel imidazole-chalcone derivatives were designed and synthesized as microtubule protein polymerization inhibitors. The proliferation inhibitory activities of the derivatives against SiHa (human cervical squamous cell carcinoma), C-33A (human cervical cancer), HeLa (human cervical cancer), HeLa/DDP (cisplatin-resistant human cervical cancer), and H8 (human cervical epithelial immortalized) cells were evaluated. Compound 5a exhibited significant anticancer activity with IC50 values ranging from 2.28 to 7.77 μM and a resistance index (RI) of 1.63, while showing minimal toxicity to normal H8 cells. When compound 5a was coadministered with cisplatin, the RI of cisplatin to HeLa/DDP cells decreased from 6.04 to 2.01, while compound 5a enhanced the fluorescence intensity of rhodamine 123 in HeLa/DDP cells. Further studies demonstrated that compound 5a arrested cells at the G2/M phase, induced apoptosis, reduced colony formation, inhibited cell migration, and inhibited cell invasion. Preliminary mechanistic studies revealed that compound 5a decreased the immunofluorescence intensity of α-/β-tubulin in cancer cells, reduced the expression of polymerized α-/β-tubulin, and increased the expression of depolymerized α-/β-tubulin. Additionally, the molecular docking results demonstrate that compound 5a can interact with the tubulin colchicine binding site and generate multiple types of interactions. These results suggested that compound 5a has anticancer effects and significantly reverses cervical cancer resistance to cisplatin, which may be related to its inhibition of microtubule and P-glycoprotein (P-gp) activity.

Effect of miR-138 on migration and invasion of cervical cancer cells, and the underlying mechanism

Purpose: To study the influence of microRNA-138 (miR-138) on the migration and invasion of cervical cancer cells, and the underlying mechanism.
 Methods: Fifteen cervical carcinoma subjects were enrolled in the study. Control group comprised cervical epithelial cell line (End1/E6E7) while cervical cancer group was human cervical squamous cell carcinoma cell line c33a. Both were cultured routinely without any treatment. In miR-138 overexpression group, cells were cultured in progeny of human cervical squamous carcinoma cell line c33a infected with miR-138 gene overexpression lentivirus. Expression levels of miR-138 in excised cervical cancer tissues were determined using qPCR. Cell proliferation was determined with CCK8 assay. Immunoblotting was utilized to assay protein expression levels. Quantitative real-time polymerase chain reaction (qRT-PCR) was used to determine mRNA expression levels, while cell migration and invasion were assessed by Transwell method.
 Results: There was significant down-regulation of miR-138 expression in cervical cancer tissue, relative to nearby tissues (p < 0.05). In miR-138 overexpression group, cell proliferation, number of migrated and invaded cells were significantly reduced, relative to corresponding levels in cervical cancer cells. There were significantly higher expression levels of apoptosis-related proteins FAS, Bax and FasL in miR-138 overexpression group than in cervical cancer cells, while Bcl-2 was significantly downregulated, relative to cervical cancer group (p < 0.05). In cervical cancer cells, mRNA and protein levels of SIRT1 and HIF-1α were significantly up-regulated, relative to corresponding control, but levels of HIF1α and miR-138 were significantly reduced in overexpression group when compared to cervical cancer group (p < 0.05).
 Conclusion: Up-regulating miR-138 in cervical cancer cells reduces HIF-1α through inhibition of SIRT1 signaling, resulting in suppression of multiplication, migration and invasion of cervical cancer cells, while enhancing apoptotic changes.

DUSP1 regulates the JAK2/STAT3 signaling pathway through targeting miR-21 in cervical cancer cells.

This study was to investigate the effect of DUSP1 on cervical cancer (CC) cells by targeting the miR-21 regulatory JAK2/STAT3 signaling pathway. For this purpose, fifteen CC patients treated at our hospital from January 2021 to February 2023 were selected. CC tissues and para-cancerous (PC) tissues were collected from the patients, and DUSP1 protein and mRNA expression levels were detected by Western blot and qPCR. The C33a control group (COG) and DUSP1 overexpression group (OVG) were set up: human cervical squamous carcinoma cells (CSCC) in the C33a COG were cultured without any treatment, while the DUSP1 OVG was cultured using DUSP1 gene overexpression lentivirus infection progeny. The proliferation ability of the three groups of cells was measured by CCK8, protein and mRNA expression by Western blot and qPCR, and cell migration and invasion ability by Transwell. It was found that DUSP1 protein and mRNA in CC tissues were reduced compared with those in PC tissues (P<0.05). The miR-21 in the DUSP1 OVG was reduced than those in the C33a COG (P<0.05). The expression of JAK2, STAT3 mRNA and protein in the DUSP1 OVG were reduced compared with those in the C33a COG (P<0.05). In conclusion, overexpression of DUSP1 can target and reduce the expression of miR-21, block the JAK2/STAT3 signaling pathway, reduce the viability of CC cells, inhibit the proliferation and migration and invasion ability of CC cells, and induce apoptosis of CC cells, thus providing a theoretical basis for the targeted treatment of clinical CC.

Single-cell dissection of cellular and molecular features underlying human cervical squamous cell carcinoma initiation and progression.

Cervical squamous cell carcinoma (CESC) is a prototypical human cancer with well-characterized pathological stages of initiation and progression. However, high-resolution knowledge of the transcriptional programs underlying each stage of CESC is lacking, and important questions remain. We performed single-cell RNA sequencing of 76,911 individual cells from 13 samples of human cervical tissues at various stages of malignancy, illuminating the transcriptional tumorigenic trajectory of cervical epithelial cells and revealing key factors involved in CESC initiation and progression. In addition, we found significant correlations between the abundance of specific myeloid, lymphoid, and endothelial cell populations and the progression of CESC, which were also associated with patients' prognosis. Last, we demonstrated the tumor-promoting function of matrix cancer-associated fibroblasts via the NRG1-ERBB3 pathway in CESC. This study provides a valuable resource and deeper insights into CESC initiation and progression, which is helpful in refining CESC diagnosis and for the design of optimal treatment strategies.

Britannin Induces Autophagy-Dependent Apoptosis via the Reactive Oxygen Species/Adenosine 5′-monophosphate-Activated Protein Kinase-unc-51-Like Autophagy Activating Kinase 1 Axis in Cervical Cancer as Detected Using Nanomagnetic Beads

Cervical cancer is a unique and common malignancy that occurs in women. Britannin has been proven to inhibit the progression of human liver and breast cancers. However, its efficacy in cervical cancer is still unclear. Human cervical squamous cell carcinoma SiHa cells were used to analyze the effect of britannin administration on cervical tumors by xenotransplantation of human tumor cells. The Cell Counting Kit-8 was used to determine the half maximal inhibitory concentration (IC50) of britannin on SiHa, and the cell invasion ability was measured using Transwell invasion assay. Cell migration was measured using the scratch-healing assay, while the clonogenic assay was performed to determine cell proliferation. Dichloro-dihydro-fluorescein diacetate was used to label reactive oxygen species (ROS) in cells or tissues. Intracellular autophages were stained with monodansylcadaverine. Western blotting assisted by nanomagnetic beads was performed to study the expression of p62, light chain 3 beta (LC3B), Beclin 1, and autophagy-related protein 5 (ATG5) in cells or tissues, as well as the phosphorylation of AMP-activated protein kinase (AMPK) and unc-51-like autophagy activating kinase 1 (ULK1). Hematoxylin and eosin staining was performed to analyze the pathological changes in the tumor cells. The expression of Ki-67, B-cell lymphoma 2 (Bcl-2), and Bax in the tumor cells was analyzed by immunohistochemistry. The IC50 obtained for britannin against SiHa was 10.01 μM. Britannin inhibited the proliferation, invasion, and migration of SiHa cells, and promoted the generation and autophagy of ROS in tumor cells and tissues. Furthermore, p-AMPK/AMPK and p-ULK1/ULK1, LC3B, Beclin 1, and ATG5 were upregulated, whereas p62 was downregulated in cells and tissues. Tumor development was inhibited; tissue inflammation was reduced; Ki-67 and Bcl-2 expression was downregulated; and Bax expression was upregulated. The expression of cleaved caspase-3, cleaved poly-ADP-ribose polymerases, and voltage-dependent anion-selective channel 1 was upregulated. These effects can be partially reversed by the AMPK inhibitor dorsomorphin dihydrochloride (BML-275). In vivo and in vitro studies showed that britannin upregulated the of ROS content of human cervical squamous cell carcinoma cells, leading to significant autophagy, thereby inhibiting the occurrence and development of cervical squamous cell carcinoma. The mechanism may be related to the ROS/AMPK/ULK1 signaling pathway.

HOXA5 inhibits the proliferation and metastasis of cervical squamous cell carcinoma by suppressing the β-catenin/Snail signaling.

HOXA5, as a transcription factor, plays an important role in a variety of malignant tumors. Nevertheless, its biological role in cervical squamous cell carcinoma (CSCC) is largely unknown. In our study, we aimed to explore the function of HOXA5 in CSCC and its molecular mechanism. Immunohistochemistry showed that HOXA5 expression was downregulated in human CSCC tissues and HOXA5 staining was negatively correlated with tumor size and histological grade of CSCC. Ectopic expression of HOXA5 inhibited proliferative and metastatic abilities of CSCC cells in vitro and in vivo. Furthermore, overexpression of HOXA5 inhibited the cell cycle by arresting the S/G2 phase by flow cytometry and that was related to the downregulation of Cyclin A. Further study showed that HOXA5 suppressed EMT by inhibiting the β-catenin/Snail signaling resulting in reduced metastasis of CSCC cells. Altogether, our results suggested that HOXA5 inhibited the proliferation and metastasis via repression of the β-catenin/Snail pathway, proposing the potential role of HOXA5 in the prevention and treatment of CSCC.

Moesin Serves as Scaffold Protein for PD-L1 in Human Uterine Cervical Squamous Carcinoma Cells.

Immune checkpoint blockade (ICB) therapy targeting the programmed death ligand-1 (PD-L1)/PD-1 axis has emerged as a promising treatment for uterine cervical cancer; however, only a small subset of patients with uterine cervical squamous cell carcinoma (SCC) derives clinical benefit from ICB therapies. Thus, there is an urgent unmet medical need for novel therapeutic strategies to block the PD-L1/PD-1 axis in patients with uterine cervical SCC. Here, we investigated the involvement of ezrin/radixin/moesin (ERM) family scaffold proteins, which crosslink several plasma membrane proteins with the actin cytoskeleton, on the plasma membrane localization of PD-L1 in BOKU and HCS-2 cells derived from human uterine cervical SCC. Immunofluorescence analysis showed that PD-L1 colocalized with all three ERM proteins in the plasma membrane. Gene knockdown of moesin, but not ezrin and radixin, substantially reduced the plasma membrane expression of PD-L1, with limited effect on mRNA expression. An immunoprecipitation assay demonstrated the molecular interaction between PD-L1 and moesin. Moreover, phosphorylated, i.e., activated, moesin was highly colocalized with PD-L1 in the plasma membrane. In conclusion, moesin may be a scaffold protein responsible for the plasma membrane expression of PD-L1 in human uterine cervical SCC.

MiR-99a-5p Constrains Epithelial-Mesenchymal Transition of Cervical Squamous Cell Carcinoma Via Targeting CDC25A/IL6.

MiR-99a-5p participates in processes and pathogenesis of varying diseases. However, the molecular mechanism of miR-99a-5p in human cervical squamous cell carcinoma (CSCC) remains unclear. Here, we found that miR-99a-5p was lowly expressed in CSCC cells and negatively associated with overall survival. In addition, cellular experiments including CCK8, wound healing, Transwell and flow cytometry assays disclosed that transfection of miR-99a-5p mimic could suppress the cell activity, cell migratory, and invasive abilities, and promote cell apoptosis, thus inhibiting the tumor progression of CSCC cells. Luciferase reporter gene assay indicated that miR-99a-5p targeted 3'-UTR of CDC25A. Also, enforced CDC25A level rescued the impact of miR-99a-5p on CSCC progression. Silencing CDC25A could restrain the mRNA and protein levels of IL-6 in CSCC. CDC25A overexpression or IL-6 treatment could attenuate inhibiting impact of miR-99a-5p overexpression on epithelial-mesenchymal transition (EMT). These findings suggested that miR-99a-5p may play an anti-tumor role in tumor metastasis by targeting CDC25A/IL6 to hamper EMT process, which revealed a novel molecular mechanism in CSCC.

Increased expression of SRPK1 (serine/arginine-rich protein-specific kinase 1) is associated with progression and unfavorable prognosis in cervical squamous cell carcinoma

ABSTRACT Previous studies suggest that SRPK1 (serine/arginine-rich protein-specific kinase 1) is involved in tumorigenesis and closely related to unfavorable outcomes. However, its expression pattern in cervical squamous cell carcinoma (CESC) remains uncovered. In this study, we initially investigated the clinical significance and function of SRPK1 in human CESC. Data mining and analysis on SRPK1 mRNA expression in CESC samples were conducted using TCGA database, which indicated that SRPK1 mRNA was significantly upregulated in CESC samples. Protein expression of SRPK1 was tested by immunohistochemistry in a retrospective cohort (n = 122), revealing a higher SRPK1 protein abundance in CESC specimens whose aberrant up-regulation was obviously related to worse survival. Cox proportional hazards regression analysis further confirmed the role of SRPK1 as an independent prognostic factor of CESC. Cellular experiments validated that SRPK1 may function through enhancing CESC proliferation, migration, and invasion. In conclusion, aberrant up-regulation of SRPK1 is remarkably related to progression and unfavorable prognosis of CESC, which can serve as a novel prognostic biomarker and therapeutic target for CESC.

Synthesis of 3-(2-(subsituted-(trifluoromethyl)phenylamino)acetyl)-2H-chromen-2-one derivatives as new anticancer agents

Under solvent free conditions and in presence of a base 3-(2-(subsituted-(trifluoromethyl)phenylamino)acetyl)-2H-chromen-2-one derivatives were synthesized by grinding technique. Structural investigations were carried out with IR studies, HRMS, 1HNMR and 13CNMR. The compounds were checked for their in vitro anticancer activities against three different human cancer cell lines viz human breast cancer cell line (MCF-7), human cervical cancer cell line (HeLa) and human oral squamous cell carcinoma (SCC-40) using SRB method. All the title compounds showed low toxicity towards non-malignant PBMC cells indicating their tumour selectivity. The compounds exhibited good in vitro anti-proliferative potency at lower concentrations against HeLa and MCF-7 cell lines and remain moderately active against SCC-40.

Long non-coding RNA LINC00514 promotes the proliferation and invasion through the miR-708-5p/HOXB3 axis in cervical squamous cell carcinoma.

Long non-coding RNA (lncRNA) LINC00514 is a cancer-related lncRNA that has been proven to be implicated in the progression of several cancers. However, the biological function of LINC00514 in cervical squamous cell carcinoma (CSCC) remains unclear. Thus, we aimed to identify the LINC00514 expression profile in CSCC and determine its exact mechanism. Our results showed that the expression of LINC00514 was up-regulated in human CSCC tissues and cell lines. Knockdown of LINC00514 significantly inhibited the proliferation and invasion of CSCC cells, as well as suppressed tumorigenesis of CSCC in vivo. In addition, LINC00514 was found to work as a miRNA sponge for miR-708-5p and suppressed the expression of miR-708-5p in CSCC cells. Homeobox B3 (HOXB3) was found to be a target gene of miR-708-5p. Rescue assays demonstrated that miR-708-5p inhibitor attenuated the effects of LINC00514 knockdown on cell proliferation and invasion in CSCC cells. In addition, overexpression of HOXB3 reversed the inhibitory effects of miR-708-5p mimics on cell proliferation and invasion. Taken together, our findings for the first time elucidated that lncRNA LINC00514 promotes the proliferation and invasion through the miR-708-5p/HOXB3 axis in CSCC. Thus, LINC00514/miR-708-5p/HOXB3 axis might be a promising therapeutic target for the treatment of CSCC.

Glycogen synthase kinase-3β inactivation promotes cervical cancerprogression, invasion, and drug resistance.

Human papillomavirus (HPV) infection-dependent cervical cancer is one of the most common gynecological cancers and often becomes aggressive, with rapid proliferation, invasion/migration, and drug resistance. Here, 135 fresh human cervical squamous cell carcinoma (CSCC) tissue specimens, comprising 21 adjacent normal (AN), 30 cervical intraepithelial neoplasia (CIN1-3 ), 45 CSCC, and 39 drugs (chemo-radiation)-resistant cervical tumor (DRCT) tissues were included. HPV-positive (HeLa, SiHa), HPV-negative (C33A), and cisplatin-resistant (CisR-HeLa/-SiHa/-C33A) cell lines were used for in vitro studies. HPV16/18 oncoproteins E6/E7, pERK1/2, and glycogen synthase kinase-3 (GSK3) and the matrix metalloproteinases (MMPs) MMP-9/-2 were assessed using immunohistochemistry, WB, and gelatin zymography. HPV16/18 infection was observed in 16.7% of the CIN1-3 , 77.8% of the CSCC, and 89.7% of DRCT samples. Total and inactive GSK3β expressions were associated with overall CSCC progression (p=0.039 and p=0.024, respectively) and chemoresistance (p=0.004 and p=0.014, respectively). Positive correlations were observed, between the expression of E6 and pGSK3β expression (p=0.013); E6 and CSCC progression (p<0.0001)/drug resistance (p=0.0001). CisR-HeLa/-SiHa was more dependent on pGSK3β, and activation of GSK3 by SMIs (iAkt), treatment with nimbolide, or knockdown of E6/E7 reduced cisplatin resistance and promoted apoptosis. Hence, the activation of GSK3β with nimbolide and iAkt can be exploited for therapeutic interventions of cervical cancer.

Itraconazole Increases Resolvin E3 Concentration and 12/15-lipoxygenase Inhibitor Attenuates Itraconazole Cytotoxicity in Cervical Cancer Cells

The anticancer mechanism of itraconazole remains unsolved; therefore, we studied itraconazole-induced alterations in specialized pro-resolving mediators (SPMs) in cancer cells. The human cervical squamous carcinoma cell line CaSki was cultured with or without 1 μM itraconazole. Liquid chromatography/mass spectrometry analysis was conducted to identify SPMs that were influenced by itraconazole. Cell growth experiments were conducted using itraconazole and inhibitors targeting the metabolic pathways of candidate SPMs. Resolvin E3, resolvin E2, prostaglandin J2 (PGJ2), delta-12-PGJ2, and maresin 2 were identified as candidate SPMs. The 12/15-lipoxygenase inhibitor, which is involved in the conversion of 18-hydroxy-eicosapentaenoic acid to resolvin E3, attenuated the inhibitory effect of itraconazole. Inhibition of the PGJ2 metabolic pathway did not interfere with itraconazole treatment. The metabolic pathway of SPMs, including resolving E3, could be proposed as an anticancer target of itraconazole.

The Role of the Hematopoietic Cell-Specific Protein 1-Associated Protein X-1 in Human Papillomavirus 16 E2-Induced Human Cervical Squamous Carcinoma Cell Apoptosis via a Mitochondria-Dependent Pathway

Objectives: Human papillomavirus 16 (HPV 16) E2 is a transcriptional regulator that plays a key role in regulating a variety of biological responses. Hematopoietic cell-specific protein 1-related protein X-1 (HAX-1) is a mitochondrial membrane protein, and the HAX-1 gene is involved in the occurrence, growth, invasion, and metastasis of various human malignant tumors. The purpose of this study was to investigate the relationships among HPV 16 E2, the role of HAX-1 gene, and the underlying intracellular apoptotic mechanism of human cervical squamous carcinoma cells (C33a and SiHa). Methods: In this study, HAX-1 expression was examined using real-time polymerase chain reaction, Western blot, and immunohistochemical staining analysis. Apoptosis of cells was assessed by flow cytometry. The mitochondrial function was assessed by the mitochondrial copy number, reactive oxygen species (ROS) generation, the mitochondrial membrane potential (ΔΨm), and mitochondrial morphology. Results: Our study demonstrated that the expression of the HAX-1 gene was significantly increased in human cervical carcinoma tissues relative to noncancerous cervix tissues. HPV 16 E2 inhibited HAX-1 protein expression. Overexpression of HAX-1 increased the mitochondrial copy number, decreased the production of ROS, and maintained the integrity of the mitochondrial membrane and morphology. So, enhanced expression of the HAX-1 gene could abrogate the HPV 16 E2-induced cell apoptosis. Conclusion: Therefore, these data support a mechanism that HAX-1 plays a crucial role in HPV 16 E2-induced human cervical squamous carcinoma cell apoptosis in a mitochondrial-dependent manner.

Effect of claudin1 on cell proliferation, migration and apoptosis in human cervical squamous cell carcinoma.

Claudin 1 is a member of the claudin protein family that serves an important role in tight junctions. Increased or decreased expression levels of claudin 1 are found in several diseases, including breast cancer and viral infections. However, the function of claudin 1 in cervical cancer remains controversial. The aim of the present study was to investigate the biological functions of claudin 1 in different human cervical cancer cell lines. First, SiHa and ME-180 cells with stable claudin 1 overexpression or knockdown were established using lentiviral transduction, and the mRNA and protein levels were measured via reverse transcription-quantitative PCR and western blot analysis. Subsequently, cell proliferation, colony formation and migration experiments were performed in vitro using standard protocols, demonstrating that claudin 1 was able to inhibit cell proliferation and migration in both SiHa and ME-180 cells. Furthermore, cell cycle and apoptosis were detected via flow cytometry and western blotting, and the results revealed that claudin 1 inhibited cell cycle progression and promoted apoptosis. To further verify whether claudin 1 was involved in tumor growth in vivo, xenograft tumors were established in athymic mice via injecting SiHa cells overexpressing claudin 1, which was found to decrease tumor growth in vivo. Furthermore, the association between claudin 1 expression and prognosis was analyzed in different types of cancer in The Cancer Genome Atlas. Overall, the findings of the present study revealed that claudin 1 may serve an antitumor role in cervical squamous cell carcinoma and may be of value as a potential therapeutic target.

Involvement of APOBEC3B in mutation induction by irradiation.

To better understand the cancer risk posed by radiation and the development of radiation therapy resistant cancer cells, we investigated the involvement of the cancer risk factor, APOBEC3B, in the generation of radiation-induced mutations. Expression of APOBEC3B in response to irradiation was determined in three human cancer cell lines by real-time quantitative PCR. Using the hypoxanthine-guanine phosphoribosyl transferase (HPRT) mutation assay, mutations in the HPRT gene caused by irradiation were compared between APOBEC3B-deficient human hepatocellular carcinoma (HepG2) cells [APOBEC3B knocked out (KO) using CRISPR-Cas9 genome editing] and the parent cell line. Then, HPRT-mutated cells were individually cultured to perform PCR and DNA sequencing of HPRT exons. X-Irradiation induced APOBEC3B expression in HepG2, human cervical cancer epithelial carcinoma (HeLa) and human oral squamous cell carcinoma (SAS) cells. Forced expression of APOBEC3B increased spontaneous mutations. By contrast, APOBEC3B KO not only decreased the spontaneous mutation rate, but also strongly suppressed the increase in mutation frequency after irradiation in the parent cell line. Although forced expression of APOBEC3B in the nucleus caused DNA damage, higher levels of APOBEC3B tended to reduce APOBEC3B-induced γ-H2AX foci formation (a measure of DNA damage repair). Further, the number of γ-H2AX foci in cells stably expressing APOBEC3B was not much higher than that in controls before and after irradiation, suggesting that a DNA repair pathway may be activated. This study demonstrates that irradiation induces sustained expression of APOBEC3B in HepG2, HeLa and SAS cells, and that APOBEC3B enhances radiation-induced partial deletions.

Cloning of the XPD gene and its function in malignant melanoma cells.

The xeroderma pigmentosum group D (XPD) gene is a member of the transcription factor IIH complex and serves an important role in gene repair. Previous studies have suggested that genetic variants of the XPD gene may be associated with an increased risk of cutaneous melanoma. However, the exact mechanism remains unclear. In the present study, the XPD gene was cloned, and its localization and function in malignant melanoma cells were investigated. The human full length XPD gene was cloned via reverse transcription-PCR using the total RNA extracted from human cervical squamous cell carcinoma epithelial HeLa cells. Subsequently, the gene was inserted into a plasmid fused to green fluorescent protein (GFP; pEGFP-N1/XPD), and pEGFP-N1/XPD and pcDNA3.1(+)/XPD were transfected into human malignant melanoma A375 cells using Lipofectamine® 2000. The expression levels of XPD were detected by western blotting. The Golgi marker GM130 and the endoplasmic reticulum membrane protein marker KDEL were used for immunofluorescence staining, and the subcellular localization of XPD was observed under a fluorescence microscope. Cell proliferation was measured using an MTT assay. The recombinant pEGFP-N1/XPD plasmid expressing the human wild-type XPD gene was successfully constructed by restriction enzyme digestion and assessed by gene sequencing. XPD was localized in the endoplasmic reticulum of malignant melanoma A375 cells, as confirmed by immunofluorescence staining. Furthermore, MTT assays indicated that XPD inhibited the proliferation of malignant melanoma A375 cells. The present study provides a basis for further investigation of the biological effects and functions of XPD in malignant melanoma cells.

Efficient isolation, culture, purification, and stem cell expression profiles of primary tumor cells derived from uterine cervical squamous cell carcinoma.

Since not too many human uterus cervical squamous cell carcinoma (CSCC) cell lines in existence, efficient isolation, culture, and purification protocols for primary CSCC cells were optimized as a tool for the study of uterus CSCC. The protocols for partial multiple enzymatic digestion and explant cell culture were combined and then the resulting mixed cell component cultures were purified by magnetic-activated cell sorting. Colony-forming assay was utilized for detection of cell carcinogenesis potential, and immunofluorescence was used to detect protein expression of CSCC. Finally, flow cytometry (FCM) was performed to analyze cancer stem cells (CSCs) phenotypic markers as well as programmed cell death ligand 1(PD-L 1). Freshly isolated cells containing tumor cells and cancer-associated fibroblasts (CAFs) efficiently proliferate to 85% confluence on a 6cm petri dish in 5-7days. Anti-epithelial cell adhesion molecule antibody (EpCAM) microbeads were used to successfully separate a homogeneous subpopulation of epithelial tumor cells. Both EpCAM+ and EpCAM- cell subpopulations were able to be passaged more than 30 times. Proportions of tumor cell populations expressed CSCs markers such as CD133, CD24, aldehyde dehydrogenase 1 (ALDH1), and CD44. The vimentin+ & EpCAM- population, defined with CAFs, could express CD146 mesenchymal stem cells marker. Meanwhile, PD-L 1 was identified in most subpopulation of CD44+ cells at low passage numbers. Efficient isolation, culture, and purification protocols for primary CSCC cells were successfully built. Additionally, the profiling of CSCs cell markers might provide promising therapeutic targets and clinic strategies.

Knockdown of Ubiquitin-Specific Protease 53 Enhances the Radiosensitivity of Human Cervical Squamous Cell Carcinoma by Regulating DNA Damage-Binding Protein 2.

Background:Cervical cancer ranks fourth in incidence and mortality among women. Ubiquitin-specific protein 53 binds to damage-specific DNA binding protein 2 and affects the biological properties of colon cancer. Damage-specific DNA binding protein is involved in nucleotide excision repair, which can repair DNA damage. However, the mechanism by which ubiquitin-specific protein 53 regulates the radiosensitivity of cervical cancer through damage-specific DNA binding protein remains unclear.Methods:Tissue samples from 40 patients with cervical squamous cell carcinoma who received radiotherapy were examined by immunohistochemistry to detect the expression of ubiquitin-specific protein 53, and clinical data were collected for statistical analysis. The cell cycle was detected by flow cytometry in Siha cells transfected with Si-USP53 and exposed to 8 Gy irradiation. Cell viability was determined by the CCK8 method in cells transfected with Si-USP53 and exposed to 0, 2, 4, 6, 8, or 10 Gy. The expression of damage-specific DNA binding protein, cyclin-dependent kinase 1, and cell cycle checkpoint kinase 2 was detected in cells transfected with Si-USP53.Results:The expression of ubiquitin-specific protein 53 in the tissues of patients with cervical squamous cell carcinoma was correlated with the sensitivity to radiotherapy. Knockdown of ubiquitin-specific protein 53 in Siha cells downregulated damage-specific DNA binding protein and caused G2/M cell cycle arrest and decreased the survival rate of cells in response to radiation.Conclusion:Ubiquitin-specific protein 53–induced cell cycle arrest and affected the radiotherapy sensitivity of tumors through damage-specific DNA binding protein.