Mechanism of collagen biosynthesis up-regulation in cultured leiomyoma cells.

Uterine leiomyoma is the most common tumour in women with a reported incidence of 25-30%. The tumors are benign, composed of smooth muscle cells with variable amount of collagen - rich fibrous tissue. It is well established that accumulation of extracellular matrix in leiomyoma is key feature of tissue fibrosis. However, the pathogenesis of leiomyoma is still unclear. The aim of this study was to evaluate the metabolism of collagen in cultured leiomyoma cells and in control myometrium cells. The effect of estradiol, selective modulators of estrogen receptors (raloxifene, tamoxifen) and estrogen receptor down regulator (ICI 182.780) on collagen biosynthesis (measured by 5-[3H]-proline incorporation assay and measurement of prolidase activity) and collagen degradation (measured by metalloproteinase activity assay) was studied. It was found that collagen biosynthesis is strongly stimulated by low doses of estradiol (5 nM) in leiomyoma cells while it is not changed in control myometrium cells. An increase in estradiol concentration to 10 nM results in drastic decrease of this process both in leiomyoma as well as control cells. Although raloxifene and tamoxifen only slightly affected collagen biosynthesis in control myometrium cells, they significantly inhibited the process in leiomyoma cells. There was no coordinate correlation between collagen biosysignificantly inhibited the process in leiomyoma cells. There was no coordinate correlation between collagen biosynthesis and prolidase activity suggesting that regulation of this process may take place at transcriptional level. Both estrogen and SERMs were found to inhibit MMP-2 in leiomyoma as well as in control myometrium cells. The data suggest that stimulatory action of estrogen on collagen biosynthesis and inhibitory effect on MMP-2 activity in uterine leiomyoma may contribute to accumulation of this protein in ECM of this tissue

Functional Consequences of Intracellular Proline Levels Manipulation Affecting PRODH/POX–Dependent Pro-Apoptotic Pathways in a Novel in Vitro Cell Culture Model

Background/Aims: The effect of impaired intracellular proline availability for proline dehydrogenase/proline oxidase (PRODH/POX)-dependent apoptosis was studied. Methods: We generated a constitutively knocked-down PRODH/POX MCF-7 breast cancer cell line (MCF-7shPRODH/POX) as a model to analyze the functional consequences of impaired intracellular proline levels. We have used inhibitor of proline utilization in collagen biosynthesis, 2-metoxyestradiol (MOE), inhibitor of prolidase that generate proline, rapamycin (Rap) and glycyl-proline (GlyPro), substrate for prolidase. Collagen and DNA biosynthesis were evaluated by radiometric assays. Cell viability was determined using Nucleo-Counter NC-3000. The activity of prolidase was determined by colorimetric assay. Expression of proteins was assessed by Western blot and immunofluorescence bioimaging. Concentration of proline was analyzed by liquid chromatography with mass spectrometry. Results: PRODH/POX knockdown decreased DNA and collagen biosynthesis, whereas increased prolidase activity and intracellular proline level in MCF-7shPRODH/POX cells. All studied compounds decreased cell viability in MCF-7 and MCF-7shPRODH/POX cells. DNA biosynthesis was similarly inhibited by Rap and MOE in both cell lines, but GlyPro inhibited the process only in MCF-7shPRODH/POX and MOE+GlyPro only in MCF-7 cells. All the compounds inhibited collagen biosynthesis, increased prolidase activity and cytoplasmic proline level in MCF-7shPRODH/POX cells and contributed to the induction of pro-survival mode only in MCF-7shPRODH/POX cells. In contrast, all studied compounds upregulated expression of pro-apoptotic protein only in MCF-7 cells. Conclusion: PRODH/POX was confirmed as a driver of apoptosis and proved the eligibility of MCF-7shPRODH/POX cell line as a highly effective model to elucidate the different mechanisms underlying proline utilization or generation in PRODH/POX-dependent pro-apoptotic pathways

The intensification of anticancer activity of LFM-A13 by erythropoietin as a possible option for inhibition of breast cancer

Recombinant human erythropoietin (Epo) is an effective and convenient treatment for cancer-related anaemia. In our study for the first time, we evaluated the effect of simultaneous use of Epo and Bruton’s tyrosine kinase (BTK) inhibitor LFM-A13 on the viability and tumour development of breast cancer cells. The results demonstrated that Epo significantly intensifies the anticancer activity of LFM-A13 in MCF-7 and MDA-MB-231. The featured therapeutic scheme efficiently blocked the tumour development in zebrafish experimental cancer model. Epo and LFM-A13 administered together resulted in effective cell killing, accompanied by attenuation of the BTK signalling pathways, loss of mitochondrial membrane potential (MMP), accumulation of apoptotic breast cancer cells with externalised PS, a slight increase in phase G0/G1 and a reduction in cyclin D1 expression. Simultaneous use of Epo with LFM-A13 inhibited early stages of tumour progression. This therapeutic scheme may be rationale for further possible research