However, there was no significant difference in the cell surface levels of hTERT between the two cell lines. a novel function 6-Quinoxalinecarboxylic acid, 2,3-bis(bromomethyl)- of LRP/LR in contributing to telomerase activity. siRNAs targeting LRP/LR may act as a potential option therapeutic tool for malignancy treatment by (i) blocking metastasis (ii) promoting angiogenesis (iii) inducing apoptosis and (iv) impeding telomerase activity. Introduction Malignancy has become a major problem worldwide due to its increasing incidence and mortality rates. According to the World Health Organisation (WHO), malignancy accounted for 8.2 million deaths in 2012 6-Quinoxalinecarboxylic acid, 2,3-bis(bromomethyl)- alone (http://www.wcrf.org/cancer_statistics/). The 37kDa/67kDa laminin receptor precursor/ high affinity laminin receptor (LRP/LR) is usually a high affinity cell surface receptor for laminin-1, an extracellular matrix glycoprotein involved in cell growth, movement, attachment and differentiation (for evaluate: [1, 2]). The relationship between the 67kDa high affinity receptor (LR) and the 37kDa laminin receptor precursor (LRP) remains unknown. LRP/LR is usually localized around the cell surface as well as in the cytoplasm, perinuclear compartment and the nucleus. The overexpression of LRP/LR is usually obvious in multiple malignancy types, and directly correlates with the invasiveness of malignancy cells which thereby enhances the risk of malignancy metastasis [3C7]. LRP/LR further plays fundamental functions in neurodegenerative disorders such as prion diseases [8C12] and Alzheimers Disease [13C17]. Telomeres are specialised DNA-protein structures found at the ends of linear eukaryotic chromosomes. The ends of telomeres have the ability to form a telomere-loop (t-loop) structure [18]. The t-loop is usually stabilised by the Shelterin complex [19]. In this conformation, chromosome ends are guarded from degradation and illegitimate processing which could results in premature senescence, recombination and end-to-end fusions and ultimately genome instability; a hallmark of malignancy [20C22]. During semi-conservative DNA replication, DNA polymerase fails to replicate the chromosomal ends during the lagging strand synthesis, resulting in the loss of terminal sequences, a phenomenon known as end replication problem [23C25]. Cells that are unable to compensate for this mechanism experience progressive telomere shortening, which in turn triggers growth arrest called replicative senescence [26C28]. Replicative senescence is usually a tumor protective mechanism which cells have to bypass to acquire immortality [29]. Telomeres are managed and replenished by telomerase. Telomerase is usually a holoenzyme and a cellular ribonucleoprotein that is involved Rabbit Polyclonal to Connexin 43 in the addition of TTAGGG 6-Quinoxalinecarboxylic acid, 2,3-bis(bromomethyl)- repeats to the 3?end of chromosomes. It is composed of two essential components, the enzymatic reverse transcriptase catalytic subunit, hTERT and the integral RNA 6-Quinoxalinecarboxylic acid, 2,3-bis(bromomethyl)- component, hTR or hTERC [30, 31]. hTERT overexpression and telomerase activity are detected in highly proliferative cells such as embryonic cells, germline cells, adult stem cells and most malignancy types [32, 33]. Telomerase stimulates tumor progression by stabilizing the telomeres to prevent the induction of replicative senescence and/or apoptosis. Therefore elevated telomerase activity could prevent a pro-cancer activity and still function as an anti-aging factor by elongating existing telomeres and preventing an accumulation of short telomeres [34, 35]. As LRP/LR and hTERT both play a role in malignancy progression and share sub-cellular localizations, we sought to investigate a possible correlation between LRP/LR and telomerase activity. Materials and Methods Cell culture Human embryonic kidney cells (HEK293) were cultured in Dulbeccos Modified Eagle Medium (DMEM) high glucose (Hyclone). MDA_MB231 breast cancer cells were cultured in DMEM/Hams-F12 (1:1). All media was supplemented with 10% fetal calf serum (FCS) and 1% penicillin/streptomycin. The cells were cultured at 37C and 5% CO2. Non-tumorigenic HEK293 cells were used as the positive control as they exhibit high telomerase activity whereas the tumorigenic MDA_MB231 cells were used as the experimental model as they are.