The phrase "a positive autocrine loop" is correct and usable in written English.
It can be used in scientific or medical contexts, particularly when discussing cellular signaling mechanisms.
Example: "The study revealed that the tumor cells were able to sustain their growth through a positive autocrine loop, enhancing their proliferation."
Alternatives: "a reinforcing autocrine loop" or "a self-stimulating autocrine loop".
It was suggested that IL-24 through a positive autocrine loop induced amplification of its own expression as well as cellular stress leading to apoptosis of malignant cells [38].
Furthermore, in all these cell lines RA also induces Ret tyrosine kinase receptor expression [17] and we have recently demonstrated that in SK-N-BE cells, the RA-treatment induces a positive autocrine loop that sustains Ret activation and downstream signalling and depends on glial-derived neurotrophic factor (GDNF, P39905 Swiss-Prot accession number) expression and release.
Our results suggest a positive autocrine loop.
We demonstrate increased c-Met expression and phosphorylation in VSMCs 2 days after culture in osteogenic medium, which precedes the up-regulation of HGF secretion detected at day 5, suggesting that, under these conditions, a positive autocrine loop may exist between c-Met activation and HGF expression.
NRP2 maintains the tumour initiating cell compartment by stimulating α6β1 integrin, FAK-mediated activation of Ras signalling and consequent induction of the zinc finger transcription factor and Hedgehog effector GLI1, which in turn induces the stem cell factor BMI1 (Lobo et al, 2007), enhances NRP2 expression and α6β1 function, thus establishing a positive autocrine loop.
This finding supports earlier evidence of a positive autocrine feedback loop [ 40].
IL-21 is produced by activated CD4+ T cells and NKT cells and is induced by IL-6 and by a positive autocrine feedback loop [ 8, 35].
This means that the IL-6/STAT3 pathway in the co-cultures was activated by the IL-6 produced and secreted into the conditioned media, suggesting a positive autocrine feedback loop in such a co-culture environment which may function to augment IL-6 signals to neighboring BMSCs.
Stellate quiescent cells are triggered to proliferate by high molecular weight serum factors [ 15] and may be subjected to a positive autocrine and paracrine feedback loop of growth factor stimulation.
In particular, cells from degenerate IVDs respond to IL-1 with a further increase in IL-1 gene expression (i.e. there is a positive autocrine effect), while cells from non-degenerate discs showed a decrease, suggesting that the normal homeostatic response to IL-1 is replaced in the degenerate IVD by a positive feedback loop.
These results demonstrate the existence of a positive Cripto/Nodal autocrine loop in postnatal spermatogonia.
