Is there a role for ibandronate in the treatment of prostate cancer patients with bony metastases?

Functional and analytical recapitulation of osteoclast biology on demineralized bone paper

Osteoclasts are the primary target for osteoporosis drug development. Recent animal studies revealed the crucial roles of osteoblasts in regulating osteoclastogenesis and the longer lifespans of osteoclasts than previously thought with fission and recycling. However, existing culture platforms are limited to replicating these newly identified cellular processes. We report a demineralized bone paper (DBP)-based osteoblast culture and osteoclast assay platform that replicates osteoclast fusion, fission, resorption, and apoptosis with high fidelity and analytical power. An osteoid-inspired DBP supports rapid and structural mineral deposition by osteoblasts. Coculture osteoblasts and bone marrow monocytes under biochemical stimulation recapitulate osteoclast differentiation and function. The DBP-based bone model allows longitudinal quantitative fluorescent monitoring of osteoclast responses to bisphosphonate drug, substantiating significantly reducing their number and lifespan. Finally, we demonstrate the feasibility of humanizing the bone model. The DBP-based osteo assay platforms are expected to advance bone remodeling-targeting drug development with improved prediction of clinical outcomes.

The miRNA let-7a1 inhibits the expression of insulin-like growth factor 1 receptor (IGF1R) in prostate cancer PC-3 cells

Reduced microRNA (miRNA) let-7a expression and the activation of insulin-like growth factor-1 receptor (IGF1R) signalling are both involved in prostate cancer and progression. In the present study, we demonstrated that the growth inhibitory effect of let-7a1 is directly related to targeting IGF1R gene expression in PC-3 cells. TargetScan predicted three potential target sites (T1, T2 and T3) of let-7a in the 3' untranslational region (3' UTR) of IGF1R mRNA. Real-time PCR, Western blot and luciferase reporter assays were used to detect the effects of let-7a1 overexpression or let-7a1 inhibitor on the IGF1R gene expression in PC-3 cells. The results indicated that let-7a1 could inhibit IGF1R expression by directly targeting the T1 and T2 sites in the 3' UTR of the IGF1R mRNA. We then used RT-PCR, luciferase reporter assays, 3-(4,5-dimethylthiazol-2-yl)-2,5- diphenyl-2H-tetrazolium bromide (MTT) assay, flow cytometry and Hoechst 33342 staining to examine whether let-7a1-mediated inhibition of IGF1R expression also affects the IGF1R-mediated signalling events, including Elk1 activity and c-fos gene expression, proliferation, apoptosis and cell cycle. We demonstrated that let-7a1-mediated IGF1R downregulation was accompanied by attenuation of Elk1 activity and c-fos expression, inhibition of cell proliferation, enhanced apoptosis and cell cycle arrest, and that loss function of let-7a1 via inhibition can upregulate IGF1R accompanied by an increase of Elk1 activity and c-fos expression, thereby enhancing cell proliferation. Altogether, these findings suggest that let-7a may be novel therapeutic candidate for prostate cancer.

Improving quality of life among cancer patients in Malaysia

There are an almost infinite number of states of health, all with differing qualities that can be affected by many factors. Each aspect of health has many components which contribute to multidimensionality. Cancer and its' related issues surrounding the treatment plan contribute to the variety of changes of quality of life of cancer patients throughout their life. The objective of this article was to provide an overview of some of the issues that can affect their quality of life and initiatives towards successful care in Malaysia by reviewing relevant reports and articles. The current strategies can be further strengthened by prevention of cancer while improving quality of service to cancer patients.

The inhibitory effects of NKX3.1 on IGF-1R expression and its signalling pathway in human prostatic carcinoma PC3 cells

NKX3.1, which is a prostate-specific homeobox gene, plays an important role in prostate cancer and usually functions as a tumour suppressor gene. In this study, we investigated the inhibitory effect of NKX3.1 on insulin-like growth factor (IGF)-1R expression and its downstream signalling pathway in PC3 cells. PC3 cells were stably transfected with NKX3.1 expression plasmid (pcDNA3.1-NKX3.1) or vector plasmid (pcDNA3.1+). The IGF-IR mRNA and protein expression levels were assessed in PC3-NKX3.1 transfectants by reverse transcriptase-polymerase chain reaction (RT-PCR) and Western blotting. The expression and activation of IGF-1/IGF-1R downstream signalling targets were examined by Western blotting and luciferase reporter assay. The cells were subsequently treated with relevant concentrations of IGF-1. The effect of IGF-1 on cell growth was examined by 3-(4,5)-dimethylthiahiazo(-z-y1)-3,5-diphenytetrazoliumromide (MTT) assay and flow cytometry analysis. A significant suppression of IGF-1R mRNA and protein expression was observed after forced expression of NKX3.1 in PC3 cells. Correspondingly, the forced expression of NKX3.1 decreased IGF-1-induced phosphorylation of extracellular signal-regulated kinase 1/2 (ERK1/2) and protein kinase B (AKT) and activation of the Elk-1 transcription factor and downregulated the expression of the downstream target genes c-fos and cyclin D1. Furthermore, the forced expression of NKX3.1 inhibited IGF-1-induced cell growth. In conclusion, NKX3.1 could downregulate IGF-1R expression and could inhibit IGF-1R-mediated mitogen-activated protein kinase (MAPK)/ERK and AKT signalling pathways, which might partially leads to the inhibition of IGF-1-induced cell growth. This study provides new insights into the molecular mechanisms that NKX3.1 exerts against prostate cancer and ultimately expands the scope of alternative approaches in advanced prostate cancer therapy.

Differential effects of ibandronate, docetaxel and farnesol treatment alone and in combination on the growth of prostate cancer cell lines

Ibandronate, one of the most potent bisphosphonates, has been shown to inhibit growth of various cancer cell lines. In contrast, little is known about the effects of ibandronate on prostate cancer cells. Therefore the aim of our study was to characterize the effects of ibandronate alone and in combination with docetaxel on the growth of prostate cancer cell lines and to identify the underlying signalling pathways. Material and methods. The prostate cancer cell lines LNCaP and PC-3 were treated with increasing concentrations of ibandronate and docetaxel alone and in combination. Viable cell number was measured after five days using a hemocytometer and the MTT-method. The effects of ibandronate were tentatively antagonized by addition of farnesyl-pyrophosphate (FPP) or farnesol (FOH). Results. Ibandronate inhibits growth of both prostate cancer cell lines in a dose dependent manner. In combination with docetaxel, synergistic effects are found as evidenced by a combination index (CI) of <1. Addition of FOH and FPP completely antagonized the growth inhibitory effects of ibandronate on both cell lines. Surprisingly, in combination with ibandronate and docetaxel, FOH further increased growth inhibition instead of antagonizing the growth inhibitory effects of ibandronate. Furthermore, FOH alone appeared to be a potent inhibitor of tumor cell growth. Discussion. Ibandronate effectively inhibits growth of prostate cancer cell lines via inhibition of the farnesyl-IPP-synthase and exhibits synergistic effects with docetaxel. In addition, FOH is a potent inhibitor of prostate cancer cell lines and may display an interesting treatment option for patients with CRPC.