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Progesterone regulates the proliferation of breast cancer cells - in vitro evidence.

Azeez JM, Sithul H, Hariharan I, Sreekumar S, Prabhakar J, Sreeja S, Pillai MR - Drug Des Devel Ther (2015)

Bottom Line: Reports state that surgery performed at different phases of the menstrual cycle may significantly affect breast cancer treatment outcome.Therefore, we further functionally characterized the protein product of TOB-1 in vitro.These results support the hypothesis that surgery conducted during the luteal phase of the menstrual cycle may facilitate improved patient survival.

View Article: PubMed Central - PubMed

Affiliation: Cancer Research Program, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, India.

ABSTRACT
Reports state that surgery performed at different phases of the menstrual cycle may significantly affect breast cancer treatment outcome. From previous studies, we identified differentially expressed genes in each menstrual cycle phase by microarray, then subjected them to functional in vitro analyses. Microarray studies disclosed genes that are upregulated in the luteal phase and follicular phase. TOB-1 is a tumor suppressor gene and was expressed exclusively in the luteal phase in our microarray study. Therefore, we further functionally characterized the protein product of TOB-1 in vitro. To our knowledge, no studies have yet been conducted on reactive oxygen species-regulated tumor suppressor interactions in accordance with the biphasic nature of progesterone. This work demonstrates that progesterone can produce reactive oxygen species in MCF-7 cells and that TOB-1 exerts a series of non-genomic interactions that regulate antiproliferative activity by modulating the antioxidant enzyme superoxide dismutase. Furthermore, this study implicates PTEN as an interacting partner for TOB-1, which may regulate the downstream expression of cell cycle control protein p27 via multiple downstream signaling pathways of progesterone through a progesterone receptor, purely in a time- and concentration-dependent manner. These results support the hypothesis that surgery conducted during the luteal phase of the menstrual cycle may facilitate improved patient survival.

No MeSH data available.


Related in: MedlinePlus

Progesterone activates TOB-1, PR, and p53 in breast cancer cells.Notes: (A) MCF-7 cells were treated with progesterone for the indicated periods of time (0–72 hours) and harvested. The lysate was analyzed by Western blot analysis for its content of total TOB-1 (A), PR (B), and p53 (C). Relative intensities of bands were normalized to β-actin and shown as graphical representations (B and D).Abbreviations: PR, progesterone receptor; h, hours; min, minutes.
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f2-dddt-9-5987: Progesterone activates TOB-1, PR, and p53 in breast cancer cells.Notes: (A) MCF-7 cells were treated with progesterone for the indicated periods of time (0–72 hours) and harvested. The lysate was analyzed by Western blot analysis for its content of total TOB-1 (A), PR (B), and p53 (C). Relative intensities of bands were normalized to β-actin and shown as graphical representations (B and D).Abbreviations: PR, progesterone receptor; h, hours; min, minutes.

Mentions: In view of the contradicting reports of Love et al4 and Hortobagyi,1 our earlier microarray gene expression analyses revealed key genes that are noticeably downregulated in the luteal phase with anti-invasive and anti-metastatic properties. Although estrogen is a major stimulant of mammary cell proliferation, the effect of progesterone remains controversial. As epidemiological data6 have shown that a progesterone-rich phase has a role in surgery timing and patient prognosis, we conducted a detailed study of the stimulatory role of progesterone. Reports regarding the biphasic nature of progesterone also exist.22–24 Notably, PRA and PRB are expressed in most human target cells, suggesting the involvement of alternative mechanisms that control the diversity of progesterone actions.25 As TOB-1 is a well-known tumor suppressor in breast cancer,19 which showed consistent positivity in our clinical samples (Figure 1) in our earlier studies, we focused on the functional characterization of TOB-1 in the presence of a physiological level of progesterone in vitro. The optimum concentration of progesterone in the selected cells was determined by an 3-(4,5-dimethythiazol- 2-yl)-2, 5-diphenyl tetrazolium bromide (MTT)-based cytotoxicity assay (Figure S2) and cell viability assay by fluorescence-activated cell sorting (FACS) (Figure S3) and compared with that reported in previous research. Initial studies of cells treated with progesterone revealed23,24 a time-dependent regulation of TOB-1 in MCF-7 cells (Figure 2).


Progesterone regulates the proliferation of breast cancer cells - in vitro evidence.

Azeez JM, Sithul H, Hariharan I, Sreekumar S, Prabhakar J, Sreeja S, Pillai MR - Drug Des Devel Ther (2015)

Progesterone activates TOB-1, PR, and p53 in breast cancer cells.Notes: (A) MCF-7 cells were treated with progesterone for the indicated periods of time (0–72 hours) and harvested. The lysate was analyzed by Western blot analysis for its content of total TOB-1 (A), PR (B), and p53 (C). Relative intensities of bands were normalized to β-actin and shown as graphical representations (B and D).Abbreviations: PR, progesterone receptor; h, hours; min, minutes.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4644174&req=5

f2-dddt-9-5987: Progesterone activates TOB-1, PR, and p53 in breast cancer cells.Notes: (A) MCF-7 cells were treated with progesterone for the indicated periods of time (0–72 hours) and harvested. The lysate was analyzed by Western blot analysis for its content of total TOB-1 (A), PR (B), and p53 (C). Relative intensities of bands were normalized to β-actin and shown as graphical representations (B and D).Abbreviations: PR, progesterone receptor; h, hours; min, minutes.
Mentions: In view of the contradicting reports of Love et al4 and Hortobagyi,1 our earlier microarray gene expression analyses revealed key genes that are noticeably downregulated in the luteal phase with anti-invasive and anti-metastatic properties. Although estrogen is a major stimulant of mammary cell proliferation, the effect of progesterone remains controversial. As epidemiological data6 have shown that a progesterone-rich phase has a role in surgery timing and patient prognosis, we conducted a detailed study of the stimulatory role of progesterone. Reports regarding the biphasic nature of progesterone also exist.22–24 Notably, PRA and PRB are expressed in most human target cells, suggesting the involvement of alternative mechanisms that control the diversity of progesterone actions.25 As TOB-1 is a well-known tumor suppressor in breast cancer,19 which showed consistent positivity in our clinical samples (Figure 1) in our earlier studies, we focused on the functional characterization of TOB-1 in the presence of a physiological level of progesterone in vitro. The optimum concentration of progesterone in the selected cells was determined by an 3-(4,5-dimethythiazol- 2-yl)-2, 5-diphenyl tetrazolium bromide (MTT)-based cytotoxicity assay (Figure S2) and cell viability assay by fluorescence-activated cell sorting (FACS) (Figure S3) and compared with that reported in previous research. Initial studies of cells treated with progesterone revealed23,24 a time-dependent regulation of TOB-1 in MCF-7 cells (Figure 2).

Bottom Line: Reports state that surgery performed at different phases of the menstrual cycle may significantly affect breast cancer treatment outcome.Therefore, we further functionally characterized the protein product of TOB-1 in vitro.These results support the hypothesis that surgery conducted during the luteal phase of the menstrual cycle may facilitate improved patient survival.

View Article: PubMed Central - PubMed

Affiliation: Cancer Research Program, Rajiv Gandhi Centre for Biotechnology, Thiruvananthapuram, India.

ABSTRACT
Reports state that surgery performed at different phases of the menstrual cycle may significantly affect breast cancer treatment outcome. From previous studies, we identified differentially expressed genes in each menstrual cycle phase by microarray, then subjected them to functional in vitro analyses. Microarray studies disclosed genes that are upregulated in the luteal phase and follicular phase. TOB-1 is a tumor suppressor gene and was expressed exclusively in the luteal phase in our microarray study. Therefore, we further functionally characterized the protein product of TOB-1 in vitro. To our knowledge, no studies have yet been conducted on reactive oxygen species-regulated tumor suppressor interactions in accordance with the biphasic nature of progesterone. This work demonstrates that progesterone can produce reactive oxygen species in MCF-7 cells and that TOB-1 exerts a series of non-genomic interactions that regulate antiproliferative activity by modulating the antioxidant enzyme superoxide dismutase. Furthermore, this study implicates PTEN as an interacting partner for TOB-1, which may regulate the downstream expression of cell cycle control protein p27 via multiple downstream signaling pathways of progesterone through a progesterone receptor, purely in a time- and concentration-dependent manner. These results support the hypothesis that surgery conducted during the luteal phase of the menstrual cycle may facilitate improved patient survival.

No MeSH data available.


Related in: MedlinePlus