title: Progesterone-induced blocking factor is hormonally regulated in human astrocytoma cells, and increases their growth through the IL-4R/JAK1/STAT6 pathway.
abstract: Astrocytomas are the most frequent and aggressive primary brain tumors in humans and constitute the leading cause of brain cancer related deaths. There are reports indicating that progesterone (P4) participates in the growth of astrocytomas through the interaction with its intracellular receptor (PR). Recently, it has been found that P4 induces the growth of several tumors through the up-regulation of progesterone-induced blocking factor (PIBF), a protein that has been related to the immunologic and proliferative actions of P4. U373 cells derived from a human astrocytoma grade III were used to study the role of P4 in PIBF expression and the effects of the latter in cell number. By using RT-PCR and Western blot techniques, we found that U373 cells express PIBF mRNA and protein. P4 (10nM and 100nM) increased PIBF mRNA expression after 1 and 3h of treatment, respectively, and this increase lasted 24h. This effect was blocked by the PR antagonist, RU486. Two PIBF isoforms were detected: one of 57kDa and the predominant one of 90kDa. The content of the 90kDa isoform increased after 12h of P4 treatment, and RU486 also blocked this increase. We observed that PIBF was released into the extracellular medium, being the 57kDa isoform the most abundant in this compartment. Immunofluorescence analysis showed that PIBF was localized in both the cytoplasm and nucleus. The effects of PIBF on cell number were analyzed for five consecutive days. PIBF (200ng/mL) significantly increased the number of U373 cells on days 2-5. Co-immunoprecipitation and Western blot assays revealed that PIBF associates to IL-4 receptor, and increases JAK1 and STAT6 phosphorylation at 20min. Our results suggest that P4 regulates PIBF expression in U373 cells through PR, and that PIBF increases cell number through IL-4 receptor/JAK1/STAT6 signaling pathway.
authors.affiliation: Facultad de Química, Departamento de Biología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Av. Universidad 3000, Coyoacán 04510, México, D.F., Mexico. Electronic address: alieshagonzalez@gmail.com.
authors.forename: Aliesha
authors.initials: A
authors.lastname: González-Arenas
authors.affiliation: Facultad de Química, Departamento de Biología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Av. Universidad 3000, Coyoacán 04510, México, D.F., Mexico.
authors.forename: Paulina
authors.initials: P
authors.lastname: Valadez-Cosmes
authors.affiliation: Facultad de Química, Departamento de Biología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Av. Universidad 3000, Coyoacán 04510, México, D.F., Mexico.
authors.forename: Carolina
authors.initials: C
authors.lastname: Jiménez-Arellano
authors.affiliation: Facultad de Química, Departamento de Biología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Av. Universidad 3000, Coyoacán 04510, México, D.F., Mexico.
authors.forename: Mónica
authors.initials: M
authors.lastname: López-Sánchez
authors.affiliation: Facultad de Química, Departamento de Biología, Universidad Nacional Autónoma de México, Ciudad Universitaria, Av. Universidad 3000, Coyoacán 04510, México, D.F., Mexico. Electronic address: camachoarroyo@gmail.com.
authors.forename: Ignacio
authors.initials: I
authors.lastname: Camacho-Arroyo
mesh_terms: D001254:Astrocytoma / Q000378:metabolism* / Q000473:pathology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D006801:Humans; D053613:Janus Kinase 1 / Q000378:metabolism; D015735:Mifepristone / Q000494:pharmacology; D011257:Pregnancy Proteins / Q000235:genetics / Q000378:metabolism*; D011374:Progesterone / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism; D019948:Receptors, Interleukin-4 / Q000378:metabolism; D011980:Receptors, Progesterone / Q000378:metabolism*; D050800:STAT6 Transcription Factor / Q000378:metabolism; D013491:Suppressor Factors, Immunologic / Q000235:genetics / Q000378:metabolism*
chemical_list: C110058:PIBF1 protein, human; D011257:Pregnancy Proteins; D012333:RNA, Messenger; D019948:Receptors, Interleukin-4; D011980:Receptors, Progesterone; D050800:STAT6 Transcription Factor; C494101:STAT6 protein, human; D013491:Suppressor Factors, Immunologic; D015735:Mifepristone; D011374:Progesterone; C507904:JAK1 protein, human; D053613:Janus Kinase 1
keywords: Astrocytomas; Gliomas; IL-4 receptor; JAK1; PIBF; Progesterone; Progesterone receptor; STAT6