RESUMO
Lentinan (LNT) isolated from Lentinus edodes is a vital host defense potentiator previously utilized as an adjuvant in cancer therapy. The present study investigated the effect of LNT on the mouse hepatocellular carcinoma (HCC) cell line Hepa16 and its possible mechanism. Mouse HCC apoptosis and its potential associated mechanism were then explored using in vitro and in vivo approaches. For in vitro approaches, the effect of LNT on the proliferation of Hepa16 cells was investigated by Cell Counting Kit8 assay. Annexin VFITC staining and flow cytometry were applied to explore HCC apoptosis. Western blotting was used to analyze related proteins, such as EGR1, phosphatase and tensin homolog (PTEN), phosphorylated protein kinase B (pAkt), protein kinase B (Akt), B lymphocyte2 (Bcl2), Bcl2 familyassociated X protein (Bax), etc. Cellular immunofluorescence staining was employed to assess the localization and expression of EGR1 and PTEN in nuclear and cytoplasmic fractions of Hepa16 cells. The association between EGR1 and PTEN was explored by EGR1 overexpression in cell lines. For in vivo methods, a mouse model of diethylnitrosamine (DEN)induced primary liver cancer was established using C57BL/6 mice to investigate the inhibitory effect of LNT on liver cancer. Histopathology of liver tissue from mice was detected by hematoxylineosin staining and immunohistochemical assay. In vitro and in vivo results showed that LNT can inhibit the proliferation and promote the apoptosis of mouse HCC cells. Besides, LNT increased the expression of EGR1 in Hepa16 cells, which is translocated to the nucleus to function as a transcriptional factor. EGR1 then activates the expression of the tumor suppressor PTEN, thereby inhibiting the activation of the AKT signaling pathway. These data revealed a novel antitumor mechanism by which LNT can induce apoptosis to inhibit mouse HCC progression through the EGR1/PTEN/AKT axis. These results provide a scientific basis for the potential use of LNT in drug development and clinical applications associated with primary liver cancer.
Assuntos
Carcinoma Hepatocelular , Neoplasias Hepáticas , Camundongos , Animais , Proteínas Proto-Oncogênicas c-akt/metabolismo , Carcinoma Hepatocelular/tratamento farmacológico , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/metabolismo , Lentinano/farmacologia , Neoplasias Hepáticas/tratamento farmacológico , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/metabolismo , Linhagem Celular Tumoral , Camundongos Endogâmicos C57BL , Camundongos Endogâmicos , Transdução de Sinais , Apoptose , PTEN Fosfo-Hidrolase/genética , PTEN Fosfo-Hidrolase/metabolismo , Proliferação de Células , Proteína 1 de Resposta de Crescimento Precoce/genética , Proteína 1 de Resposta de Crescimento Precoce/metabolismoRESUMO
Sequence variability in surface-antigenic sites of pathogenic proteins is an important obstacle in vaccine development. Over 200 distinct genomic sequences have been identified for human papillomavirus (HPV), of which more than 18 are associated with cervical cancer. Here, based on the high structural similarity of L1 surface loops within a group of phylogenetically close HPV types, we design a triple-type chimera of HPV33/58/52 using loop swapping. The chimeric VLPs elicit neutralization titers comparable with a mix of the three wild-type VLPs both in mice and non-human primates. This engineered region of the chimeric protein recapitulates the conformational contours of the antigenic surfaces of the parental-type proteins, offering a basis for this high immunity. Our stratagem is equally successful in developing other triplet-type chimeras (HPV16/35/31, HPV56/66/53, HPV39/68/70, HPV18/45/59), paving the way for the development of an improved HPV prophylactic vaccine against all carcinogenic HPV strains. This technique may also be extrapolated to other microbes.