BRCA1 deficiency enhances the aggressiveness of breast cancer cells expressing HPV16 oncoproteins.

BACKGROUND INFORMATION: The precise etiology of breast cancer is not completely understood, although women with BRCA1 gene mutations have a significantly increased risk of developing the disease. In addition, sporadic breast cancer is frequently associated with decreased BRCA1 gene expression. Growing evidence of Human papillomaviruses (HPVs) infections in breast tumors has raised the possibility of the involvement of HPVs in the pathogenesis of breast cancer. We investigated whether the effects of HPV oncoproteins E6 and E7 were influenced by the expression levels of BRCA1. HPV16E6E7 (prototype or E6D25E/E7N29S Asian variant type) were stably expressed in MDA-MB231 breast cancer cells, wild type for BRCA1, or with BRCA1 knocked down. RESULTS: Expression of HPV16E6E7 oncogenes did not affect BRCA1 levels and the abundance of HPV16E6E7 was not altered by BRCA1 knockdown. BRCA1 levels did not alter HPV16E6E7-dependent degradation of G1-S cell cycle proteins p53 and pRb. However, we found that the expression of G2-M cell cycle protein cyclin B1 enhanced by HPV16E6E7 was impacted by BRCA1 levels. Especially, we found the correlation between BRCA1 and cyclin B1 expression and this was also confirmed in breast cancer samples from a Thai cohort. We further demonstrated that the combination of HPV oncoproteins and low levels of BRCA1 protein appears to enhance proliferation and invasion. Transactivation activities of HPV16E6E7 on genes regulating cell proliferation and invasion (TGF-ß and vimentin) were significantly increased in BRCA1-deficient cells. CONCLUSIONS: Our results indicate that a deficiency of BRCA1 promotes the transactivation activity of HPV16E6E7 leading to increase of cell proliferation and invasion. SIGNIFICANCE: HPV infection appears to have the potential to enhance the aggressiveness of breast cancers, especially those deficient in BRCA1.

Cellular Retinoic Acid Binding Protein 2 (CRABP2), Up-regulated by HPV E6/E7, Leads to Aberrant Activation of the Integrin ß1/FAK/ERK Signaling Pathway and Aggravates the Malignant Phenotypes of Cervical Cancer.

The ectopic expression of cellular retinoic acid binding protein 2 (CRABP2) is associated with various tumorigenesis. However, the effects of CRABP2 on the progression of cervical cancer are still unclear. The current study aimed to investigate the role of CRABP2 in the malignant phenotypes of cervical cancer cells. CRABP2 was artificially regulated in CaSki, SiHa, and C-33A cells. CCK-8 assay and flow cytometry were used to assess the cell proliferation and apoptosis abilities, respectively. Wound healing assay and transwell assay were employed to measure the cell migration and invasion abilities, respectively. The results showed that CRABP2 was highly expressed in cervical carcinoma tissues and cell lines, and its high expression was associated with poor overall survival. Knockdown of CRABP2 promoted the cell apoptosis and inhibited cell proliferation, migration, and invasion in cervical carcinoma cells, whereas CRABP2 overexpression exhibited the opposite results. Mechanically, CRABP2 silencing suppressed the Integrin ß1/FAK/ERK signaling via HuR. Treatment with siITGB1 or a FAK inhibitor PF-562271 or an ERK inhibitor FR180204 reversed the promoting effects of CRABP2 on cell proliferation, migration, and invasion. Moreover, the overexpression of CRABP2 reverted the HPV16 E6/E7 knockdown-induced inhibition of cell proliferation, migration, and invasion in cervical cancer cells. These results suggested that HPV16 E6/E7 promoted the malignant phenotypes of cervical cancer by upregulating the expression of CRABP2. In conclusion, CRABP2, upregulated by HPV E6/E7, promoted the progression of cervical cancer through activating the Integrin ß1/FAK/ERK signaling pathway via HuR.

Local radiotherapy and E7 RNA-LPX vaccination show enhanced therapeutic efficacy in preclinical models of HPV16+ cancer.

Human papilloma virus (HPV) infection is a causative agent for several cancers types (genital, anal and head and neck region). The HPV E6 and E7 proteins are oncogenic drivers and thus are ideal candidates for therapeutic vaccination. We recently reported that a novel ribonucleic acid lipoplex (RNA-LPX)-based HPV16 vaccine, E7 RNA-LPX, mediates regression of mouse HPV16+ tumors and establishes protective T cell memory. An HPV16 E6/E7 RNA-LPX vaccine is currently being investigated in two phase I and II clinical trials in various HPV-driven cancer types; however, it remains a high unmet medical need for treatments for patients with radiosensitive HPV16+ tumors. Therefore, we set out to investigate the therapeutic efficacy of E7 RNA-LPX vaccine combined with standard-of-care local radiotherapy (LRT). We demonstrate that E7 RNA-LPX synergizes with LRT in HPV16+ mouse tumors, with potent therapeutic effects exceeding those of either monotherapy. Mode of action studies revealed that the E7 RNA-LPX vaccine induced high numbers of intratumoral-E7-specific CD8+ T cells, rendering cold tumors immunologically hot, whereas LRT primarily acted as a cytotoxic therapy, reducing tumor mass and intratumor hypoxia by predisposing tumor cells to antigen-specific T cell-mediated killing. Overall, LRT enhanced the effector function of E7 RNA-LPX-primed T cell responses. The therapeutic synergy was dependent on total radiation dose, rather than radiation dose-fractionation. Together, these results show that LRT synergizes with E7 RNA-LPX and enhances its anti-tumor activity against HPV16+ cancer models. This work paves into a new translational therapy for HPV16+ cancer patients.

Generation and characterization of human Fetal membrane and Decidual cell lines for reproductive biology experiments†.

Human fetal membrane and maternal decidua parietalis form one of the major feto-maternal interfaces during pregnancy. Studies on this feto-maternal interface is limited as several investigators have limited access to the placenta, and experience difficulties to isolate and maintain primary cells. Many cell lines that are currently available do not have the characteristics or properties of their primary cells of origin. Therefore, we created, characterized the immortalized cells from primary isolates from fetal membrane-derived amnion epithelial cells, amnion and chorion mesenchymal cells, chorion trophoblast cells and maternal decidua parietalis cells. Primary cells were isolated from a healthy full-term, not in labor placenta. Primary cells were immortalized using either a HPV16E6E7 retroviral or a SV40T lentiviral system. The immortalized cells were characterized for the morphology, cell type-specific markers, and cell signalling pathway activation. Genomic stability of these cells was tested using RNA seq, karyotyping, and short tandem repeats DNA analysis. Immortalized cells show their characteristic morphology, and express respective epithelial, mesenchymal and decidual markers similar to that of primary cells. Gene expression of immortalized and primary cells were highly correlated (R = 0.798 to R = 0.974). Short tandem repeats DNA analysis showed in the late passage number (>P30) of cell lines matched 84-100% to the early passage number (

Human papillomavirus 16 E6/E7 contributes to immune escape and progression of cervical cancer by regulating miR-142-5p/PD-L1 axis.

Persistent infection of human papillomavirus (HPV) and immune escape are the main causes of cervical cancer. E6/E7 encoded by HPV16 may be closely related to carcinogenesis. HPV infection may upregulate PD-L1 expression, resulting in immune escape and cervical cancerigenesis. Evidence indicates that miRNAs may mediate the regulation of E6/E7 on PD-L1. Therefore, we aimed to screen the miRNA, and further verify its expression and functions. Bioinformatics approaches were used to screen the miRNAs that mediate the regulation of E6/E7 on PD-L1. The expression of the miRNA and PD-L1 in HPV+ and HPV- cervical cancer cells were compared, and the effect of E6E7 on them was evaluated. Then, the effect of the miRNA on PD-L1 was assessed by the Gain- and Loss-of-function test. Finally, in vivo experiments were conducted to verify the effects of the miRNA on tumor growth and survival of tumor-bearing mice. Six miRNAs were screened, of which miR-142-5p was identified. MiR-142-5p was downregulated and PD-L1 was upregulated in HPV- cells after transfection of E6, E7, or E6/E7. The rescue test showed that the upregulation of miR-142-5p attenuated the effect of E6/E7 on PD-L1. The reverse relationship between PD-L1 and miR-142-5p was confirmed. In vivo experiments suggest that miR-142-5p upregulation inhibits the growth of the transplanted tumors by targeting PD-L1. MiR-142-5p acts as a tumor suppressor in cervical cancer. HPV16 E6E7 may promote the immune escape of cervical cancer cells by regulating the miR-142-5p/PD-L1 axis. Using miR-142-5p in tumor immunotherapy as a new strategy is proposed.

Genetic variability and functional implication of HPV16 from cervical intraepithelial neoplasia in Shanghai women.

Human papillomavirus (HPV)16 gene mutation is usually associated with persistent HPV infection and cervical intraepithelial neoplasia (CIN). However, the functional implications of HPV16 mutations remain poorly understood.145 LCR/E6/E7 of the HPV16 isolates were amplified and sequenced, and HPV16 integration status was detected. In total, 89 SNPs (68 in the LCR, 13 in E6, 8 in E7) were discovered, 11 of which were nonsynonymous mutations (8 in E6, 3 in E7). The H85Y and E120D variants in E6 were significantly reduced in the high-grade squamous intraepithelial lesion (HSIL) group compared to the T," a potential binding site for TATA-binding protein, is the most common in LCR variants. A4 (Asian) was associated with an increased risk of HSIL compared to A1-3(P = .009). The H85/E120 in E6 and N29 in HPV16 E7 might play a critical role in carcinogenesis by disrupting p53 and Rb degradation due to affecting their interaction, respectively. In a word, the findings in this study provide preventative and therapeutic interventions of HPV16 -related cervical lesions/cancer.

Novel Human Prostate Epithelial Cell Cultures.

Prostate cancer is the most common male cancer in the USA and the second leading cause of male cancer death in the USA. African American men have higher incidence and mortality rate from prostate cancer compared to Caucasian men in North America, indicating the prostate cancer is a major public health problem in this population. Studies of prostate cancer have been hampered by various factors including (1) restricted access to tissues, (2) difficulties in propagating premalignant lesions and primary prostate tumors in vitro, and (3) limited availability of prostate cell lines for in vitro studies. There is no commercially available pair of non-malignant and tumor cells derived from the same prostate cancer patient. Primary prostate epithelial cells grow for a finite life span and then senesce. Immortalization is defined by continuous growth of otherwise senescing cells and is believed to represent an early stage in tumor progression. To examine these early stages, we have developed in vitro models of prostate epithelial cell immortalization. Generation of human primary epithelial (HPE) cells has been achieved using the serum-free keratinocyte growth medium. Retrovirus containing human telomerase reverse transcriptase (hTERT) was also used for the generation of primary non-malignant and malignant tumor cells. In addition, we have established the first immortalized cell lines of a pair of non-malignant and malignant tumors derived from an African American prostate cancer patient. Interestingly, we have found that the Rock inhibitor and feeder cells induced the conditioned reprogramming (CR) of epithelial cells-normal and tumor epithelial cells from many tissues to proliferate indefinitely in vitro, without transduction of viral or cellular genes. More recently, using CR, we have established normal and tumor cultures respectively from a patient prostatectomy. These CR cells grow indefinitely in vitro and retain stable karyology. The tumor-derived CR cells produced tumors in SCID mice. The use of novel pair of non-malignant and malignant tumor cells derived from the same patient provides a unique in vitro model for studies of early prostate cancer and for testing preventive and therapeutic regimens.

HPV16 E6/E7 upregulates HIF-2α and VEGF by inhibiting LKB1 in lung cancer cells.

Long-term persistent infection of HPV16 E6/E7 is frequently associated with lung cancers, especially in non-smokers and in Asians. However, molecular mechanisms of HPV16 E6/E7 induction of lung cancer are not fully understood. Using bi-directional genetic manipulation and four well-established lung cancer cell lines, we showed HPV16 E6/E7 downregulated expression of liver kinase B1 at both protein and messenger RNA levels; liver kinase B1 downregulated hypoxia-inducible factor 2α at protein level but not at messenger RNA level, and hypoxia-inducible factor 2α upregulated vascular endothelial growth factor at both protein and messenger RNA levels. This is the first study to show hypoxia-inducible factor 2α as a downstream effector of liver kinase B1 in lung cancer cells. Our results indicate that HPV16 E6/E7 indirectly upregulated the expression of vascular endothelial growth factor by inhibition of liver kinase B1 expression and upregulation of hypoxia-inducible factor 2α expression, thus propose a human papillomavirus-liver kinase B1-hypoxia-inducible factor 2α-vascular endothelial growth factor axis for the tumorigenesis of lung cancer. Our study also provides new evidence to support the critical role of liver kinase B1 in the pathogenesis of human papillomavirus-related lung cancer and suggests novel therapeutic targets.

Genetically engineered mouse model of HPV16 E6-E7 with vaginal-cervical intraepithelial neoplasia and decreased immunity.

Objective: To construct models of high-risk human papillomavirus (HPV) infection with precancerous lesions or cervical cancer and explore the immune function. Methods: Using CRISPR/Cas9, the expression vector HPV16-E6-E7-Rosa26 was microinjected into fertilized eggs of C57BL/6 N mice using homologous recombination, and the F0 generation was obtained for reproduction. Then, the formation of precancerous lesions was promoted via intramuscular injection of estradiol. Presence of precancerous cervical-vaginal intraepithelial lesions, Ki67 and p16 expression levels, and CD8+ T cell proportions in the spleen were evaluated. Results: Two F0 generation mice exhibited correct the homologous recombination. Seven positive mice were identified in the F1 generation. After breeding and mating, 25 homozygous and 11 heterozygous HPV16-E6-E7-engineered mice were obtained from the F2 generation. After estradiol benzoate treatment, the cervical-vaginal epithelium appeared as precancerous lesions with positive Ki67 and p16 expression. The percentage of CD8+ T cells decreased. Conclusion: HPV16-E6-E7-Rosa26 induced low immune function in mice, and provides a good model for the basic research of the mechanisms of action of HPV infection-associated precancerous lesions or cervical cancer.

HPV-mediated down-regulation of NOD1 inhibits apoptosis in cervical cancer.

Cervical cancer is the fourth most common malignant tumor in women worldwide. The persistent infection of high-risk Human Papillomavirus (hrHPV) is considered to be the primary cause of this disease. As an innate immune receptor, the nucleotide-binding oligomerization domain protein-1 (NOD1) recognizes the pathogen-associated molecular pattern (PAMP), subsequently initiating immune responses. NOD1 is also involved in the apoptotic signaling pathway and mutates in many cancer cells. In the study, we revealed that NOD1 expression decreased during the progression of cervical intraepithelial neoplasia to cervical cancer and that HPV16 E6/E7 oncoproteins induced down-regulation of NOD1. Moreover, the activation of NOD1 promoted the apoptosis of HPV16-positive cervical cancer cells. The data indicated that the dysregulation of NOD1-mediated inflammation and apoptosis may contribute to cervical intraepithelial neoplasia progression and cervical cancer.

VERU-111 suppresses tumor growth and metastatic phenotypes of cervical cancer cells through the activation of p53 signaling pathway.

In this study, we investigated the therapeutic efficacy of VERU-111 in vitro and in vivo model systems of cervical cancer. VERU-111 treatment inhibited cell proliferation and, clonogenic potential, induce accumulation of p53 and down regulated the expression of HPV E6/E7 expression in cervical cancer cells. In addition, VERU-111 treatment also decreased the phosphorylation of Jak2(Tyr1007/1008) and STAT3 at Tyr705 and Ser727. VERU-111 treatment arrested cell cycle in the G2/M phase and modulated cell cycle regulatory proteins (cyclin B1, p21, p34cdc2 and pcdk1). Moreover, VERU-111 treatment induced apoptosis and modulated the expression of Bid, Bcl-xl, Survivin, Bax, Bcl2 and cleavage in PARP. In functional assays, VERU-111 markedly reduced the migratory and invasive potential of cervical cancer cells via modulations of MMPs. VERU-111 treatment also showed significant (P < 0.05) inhibition of orthotopic xenograft tumor growth in athymic nude mice. Taken together, our results demonstrate the potent anti-cancer efficacy of VERU-111 in experimental cervical cancer models.Thus, VERU-111 can be explored as a promising therapeutic agent for the treatment of cervical cancer.

Live-attenuated lymphocytic choriomeningitis virus-based vaccines for active immunotherapy of HPV16-positive cancer.

Infection with human papillomavirus (HPV) is associated with a variety of cancer types and limited therapy options. Therapeutic cancer vaccines targeting the HPV16 oncoproteins E6 and E7 have recently been extensively explored as a promising immunotherapy approach to drive durable antitumor T cell immunity and induce effective tumor control. With the goal to achieve potent and lasting antitumor T cell responses, we generated a novel lymphocytic choriomeningitis virus (LCMV)-based vaccine, TT1-E7E6, targeting HPV16 E6 and E7. This replication-competent vector was stably attenuated using a three-segmented viral genome packaging strategy. Compared to wild-type LCMV, TT1-E7E6 demonstrated significantly reduced viremia and CNS immunopathology. Intravenous vaccination of mice with TT1-E7E6 induced robust expansion of HPV16-specific CD8+ T cells producing IFN-γ, TNF-α and IL-2. In the HPV16 E6 and E7-expressing TC-1 tumor model, mice immunized with TT1-E7E6 showed significantly delayed tumor growth or complete tumor clearance accompanied with prolonged survival. Tumor control by TT1-E7E6 was also achieved in established large-sized tumors in this model. Furthermore, a combination of TT1-E7E6 with anti-PD-1 therapy led to enhanced antitumor efficacy with complete tumor regression in the majority of tumor-bearing mice that were resistant to anti-PD-1 treatment alone. TT1-E7E6 vector itself did not exhibit oncolytic properties in TC-1 cells, while the antitumor effect was associated with the accumulation of HPV16-specific CD8+ T cells with reduced PD-1 expression in the tumor tissues. Together, our results suggest that TT1-E7E6 is a promising therapeutic vaccine for HPV-positive cancers.

miR-4454 up-regulated by HPV16 E6/E7 promotes invasion and migration by targeting ABHD2/NUDT21 in cervical cancer.

The abnormal expression of HPV16 E6/E7 activates oncogenes and/or inactivates tumor suppressor genes, resulting in the selective growth and malignant transformation of cancer cells. miR-4454 was selected by sequencing due to its abnormal high expression in HPV16 E6/E7 positive CaSki cell compared with HPV16 E6/E7 negative C33A cell. Overexpression of miR-4454 enhances cervical cancer cell invasion and migration. ABHD2 and NUDT21 are identified as a target gene of miR-4454.The effects of ABHD2 and NUDT21 on migration and invasion of CaSki and C33A cells were determined. The dual luciferase and RT-qPCR assays confirmed that miR-4454 might regulate its targets ABHD2 and NUDT21 to promote the proliferation, invasion and migration, whereas, inhibit the apoptosis in CaSki and C33A cells.

Human Papillomavirus Genotypes and HPV16 E6/E7 Variants among Patients with Genital Cancers in Vietnam.

We previously reported human papillomavirus type 52 (HPV52) as the most prevalent high-risk genotype in non-cancer individuals in Vietnam. This study aimed to evaluate HPV genotypes and HPV16 E6 and E7 (E6/E7) gene variations in Vietnamese patients with genital cancers. Biopsy samples were collected from 124 Vietnamese patients with genital cancers (20 with vaginal, 50 with vulvar, and 54 with penile cancer). The HPV-DNA was amplified and genotyped, and HPV16 E6/E7 genes were compared with those previously reported for women with normal cervical cytology (N = 23). HPV-DNA was detected in 80.6% (100/124) of the cancer patients (80.0% of vaginal, 82.0% of vulvar, and 79.6% of penile), with HPV16/18 in 86.0% (86/100) and HPV52 in 7.0% (7/100) of the HPV-positive samples. The HPV-DNA prevalence and HPV genotype distribution did not significantly differ among the genital cancer patients (both P = 0.95). Significantly fewer instances of the HPV16 A4 sublineage (34.8% vs. 82.6%, P < 0.0001) and HPV16 E7 29S (36.4% vs. 87.0%, P = 0.0002) occurred in the cancer patients than in the women with normal cytology. Our results indicate that HPV16/18 accounts for more than 85% of genital cancers in Vietnam, and the HPV16 sublineage A4 containing E7 29S may be less oncogenic.

HPV-16 targeted DNA vaccine expression: The role of purification.

DNA vaccines have come to light in the last decades as an alternative method to prevent many infectious diseases, but they can also be used for the treatment of specific diseases, such as cervical cancer caused by Human Papillomavirus (HPV). This virus produces E6 and E7 oncoproteins, which alter the cell cycle regulation and can interfere with the DNA repairing system. These features can ultimately lead to the progression of cervical cancer, after cell infection by HPV. Thus, the development of a DNA vaccine targeting both proteins arises as an interesting option in the treatment of this pathology. Nonetheless, before evaluating its therapeutic potential, the purity levels of a biopharmaceutical must meet the regulatory agency specifications. Previously, our research group successfully purified the supercoiled isoform of the recombinant HPV-16 E6/E7 DNA vaccine with virtual 100% purity by affinity chromatography. The present work was designed to evaluate the effect that pDNA sample purity levels may exert in the expression of a target protein. Thus, in vitro studies were performed to assess the vaccine ability to produce the target proteins and to compare the expression efficiency between the pDNA sample obtained by affinity chromatography, which only presents the sc isoform and fulfils the regulatory agency recommendations, and the same DNA vaccine retrieved by a commercial purification kit, which contains different pDNA isoforms. Our achievements suggest that the E6/E7 DNA vaccine purified by affinity chromatography promotes higher E6 and E7 mRNA and protein expression levels than the DNA vaccine purified with the commercial kit. Overall, these results underline the importance that a purification strategy may present in the therapeutic outcome of recombinant DNA vaccines, envisaging their further application as biopharmaceuticals. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:546-551, 2018.

Quantification of HPV16 E6/E7 mRNA Spliced Isoforms Viral Load as a Novel Diagnostic Tool for Improving Cervical Cancer Screening.

High-risk human papillomaviruses (HPVs) have been identified as the main contributors to cervical cancer. Despite various diagnostic tools available, including the predominant Papanicolaou test (Pap test), technical limitations affect the efficiency of cervical cancer screening. The aim of this study was to evaluate the diagnostic performance of spliced HPV16 E6/E7 mRNA viral loads (VL) for grade 2 or higher cervical intraepithelial neoplasia diagnosis. A new dedicated (quantitative reverse transcription polymerase chain reaction) qRT-PCR assay was developed, allowing selective quantification of several HPV16 E6/E7 mRNA: Full length (FL) with or without all or selected spliced forms (total E6/E7 mRNA corresponding to SP + E6^E7 mRNA (T), + spliced E6/E7 mRNA containing intact E7 ORF (SP), and E6/E7 mRNA containing disrupted E6 and E7 ORFs calculated by the following subtraction T-SP (E6^E7)). Twenty HPV16 DNA and mRNA positive uterine cervical smears representative of all cytological and histological stages of severity were tested. We have shown that all E6/E7 mRNA isoforms expression levels were significantly increased in high grade cervical lesions. Statistical analysis demonstrated that the SP-E6/E7 VL assay exhibited: (i) The best diagnostic performance for identification of both cervical intraepithelial neoplasia (CIN)2+ (90% (56⁻100) sensitivity and specificity) and CIN3+ (100% (72⁻100) sensitivity and 79% (49⁻95) specificity) lesions; (ii) a greater sensitivity compared to the Pap test for CIN2+ lesions detection (80% (44⁻97)); (iii) a predictive value of the histological grade of cervical lesions in 67% of atypical squamous cells of unknown significance (ASC-US) and 100% of low-grade (LSIL) patients. Overall, these results highlight the value of SP-E6/E7 mRNA VL as an innovative tool for improving cervical cancer screening.

Establishment and identification of human immortalized keratinocytes stably expressing human papillomavirus type 16 E6/E7 gene / 中华皮肤科杂志

Objective:To construct human immortalized keratinocytes stably expressing human papillomavirus type 16 (HPV16) E6/E7 gene, and provide a cell model for studying mechanisms underlying HPV16 E6/E7-induced cell immortalization and malignant transformation.Methods:Primary human foreskin keratinocytes (HFKs) were isolated by sequential two-step enzymatic digestion. Cultured HFKs were stably transfected with a HPV16 E6/E7 gene-overexpressing lentiviral vector LV5-HPV16 E6/E7, and consecutively cultured for more than 30 passages. Then, immortalized keratinocytes were screened out and divided into 3 groups: (1) blank control group: second-passage primary HFKs; (2) experimental group: HFKs transfected with LV5-HPV16 E6/E7 at different passages, and the second-passage primary HFKs transfected with LV5-HPV16 E6/E7 were referred to as A0 cells, thereafter, the transfected HFKs were named according to their passage number, such as A1, A2, ... A30; (3) positive control group: the HPV16-positive cervical cancer cell line SiHa. Real-time fluorescence-based quantitative PCR (qRT-PCR) and Western blot analysis were performed to determine the mRNA expression of HPV16 E6/E7 and protein expression of HPV16 E6/E7 and CK14, respectively, in the blank control group, experimental group and positive control group. Cell counting kit-8 (CCK8) assay and Transwell insert invasion assay were conducted to assess the cellular proliferative and invasive activity. In vivo tumor formation experiment in nude mice was conducted to investigate the tumorigenicity of A30 cells in the experimental group and SiHa cells in the positive control group. Results:Primary HFKs were successfully isolated. After the primary HFKs were transfected with the recombinant plasmid LV5-HPV16 E6/E7, the blank control group showed no fluorescence in the cells, but showed senescent phenotypes after serial passages, while in the experimental group, the volume and morphology of A30 cells were similar to those of the primary HFKs with the proportion of fluorescence-positive cells being 100%. Compared with the blank control group, the experimental group showed significantly increased mRNA expression levels of HPV16 E6 and E7 in A1, A10, A20 and A30 cells (HPV16 E6: t = 7.12, 8.07, 6.53, 5.66, P < 0.001, < 0.001, = 0.001, = 0.005, respectively; HPV16 E7: t = 3.20, 4.29, 3.75, 4.22; P = 0.024, 0.008, 0.013, 0.014, respectively) . The protein expression of HPV16 E6/E7 was absent in the blank control group, but was observed in A30 and SiHa cells. CCK8 assay showed that the proliferative activity of A10, A20 and A30 cells was significantly higher than that of the blank control group ( t = 6.49, 7.55, 9.43, P = 0.003, 0.002, 0.001, respectively) , while there was no significant difference in the proliferative activity between A1 cells and the blank control group ( t = 2.40, P = 0.074) . Transwell insert invasion assay showed that A30 cells could not cross the basement membrane, but SiHa cells could pass through the basement membrane and were stained blue. Two months after the inoculation with A30 cells in the nude mice, no visible tumors were found, which was confirmed by a histological study. Subcutaneous tumors were formed in the nude mice after the inoculation with SiHa cells. Conclusion:Human immortalized keratinocytes were successfully established by lentivirus-mediated transfection with HPV16 E6/E7 gene, and can serve as an ideal cell model for HPV-related research.

Non-invasive in vivo molecular imaging of intra-articularly transplanted immortalized bone marrow stem cells for osteoarthritis treatment.

Pathophysiology of osteoarthritis (OA) is characterized by progressive loss of articular cartilage in the knee-joints. To impart regenerative ability in lowly metabolizing chondrocytes, the bone marrow stem cells (BMSCs) has recently been recognized as a superior alternative treatment for OA. However, study of primary BMSCs-mediated chondrogenesis is difficult due to progressive cellular aging and replicative senescence. To obtain a therapeutic cell population for OA, BMSCs were immortalized by human papilloma virus (HPV)-16 E6/E7 along with mCherry luciferase (mCL), a gene marker for non-invasive imaging, and designated as iBMSCs-mCL. Next, their cell morphology, population doubling time (PDT) and colony forming ability (CFU) were evaluated. Furthermore, pluripotency and immunophenotypic markers were investigated. To deduce therapeutic ability, iBMSCs-mCL were intra-articularly injected into right knee of anterior cruciate ligament transaction (ACLT)-OA mice model and tracked through non-invasive bioluminescence imaging. Cell morphology of iBMSCs-mCL was similar to parental BMSCs. PDT and CFU ability of iBMSCs-mCLs were significantly increased. Pluripotency and immunophenotypic markers were highly expressed in iBMSC-mCL. Long-term survival and tri-lineage differentiation particularly chondrogenic potential of iBMSCs-mCL were also demonstrated in vitro and then in vivo which was monitored through non-invasive imaging. Intensive bioluminescent signals in iBMSCs-mCL administered knee-joint indicated a marked in vivo survival and proliferation of iBMSCs-mCL. Immunohistochemical staining for type II collagen (IHC of Col II) and alcian blue & safranin o staining of proteoglycans also corroborated cartilage regeneration by iBMSCs-mCL. Conclusively, iBMSCs-mCL maintains stemness and in vivo cartilage regeneration potential suggesting a promising avenue for development of OA therapeutics.

HPV16 E6-E7 induces cancer stem-like cells phenotypes in esophageal squamous cell carcinoma through the activation of PI3K/Akt signaling pathway in vitro and in vivo.

High-risk human papillomavirus (HPV), especially HPV16, correlates with cancerogenesis of human esophageal squamous cell carcinoma (ESCC) and we have reported that HPV16 related with a poor prognosis of ESCC patients in China. We aim to investigate the potential role and mechanism of HPV16 in ESCC development and progress. Our following researches demonstrated that ESCC cells which were stably transfected by HPV16 E6-E7 lentiviral vector showed a remarkable cancer stem-like cells (CSCs) phenotype, such as: migration, invasion, spherogenesis, high expression of CSCs marker in ESCC---p75NTR, chemoresistance, radioresistance, anti-apoptosis ability in vitro and cancerogenesis in vivo. HPV16 E6-E7 induced PI3K/Akt signaling pathway activation and this affect could be effectively inhibited by LY294002, a specific PI3K inhibitor. It was also indicated that the inhibition of PI3K/Akt signaling pathway by PI3K and Akt siRNA reverse the effect which induced by HPV16 E6-E7 in ESCC cells. Taken together, the present study demonstrates that HPV16 E6-E7 promotes CSCs phenotype in ESCC cells through the activation of PI3K/Akt signaling pathway. Targeting the PI3K/Akt signaling pathway in HPV16 positive tissues is an available therapeutic for ESCC patients.