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Tumor cell-derived secretory factor downregulates Semaphorin-3a in osteoblasts by activating mammalian target of

Daisuke Yamada1, Kohichi Kawahara1, Masanobu Ozaki2

  • 1a Faculty of Pharmacy, Department of Pharmacology , Niigata University of Pharmacy and Applied Life Sciences , Niigata , Japan.

Bioscience, Biotechnology, and Biochemistry
|February 12, 2016
PubMed

Insights

Tumor cells reduce Semaphorin3a (Sema3a) mRNA in osteoblasts via the mammalian target of rapamycin complex 1 (mTORC1) pathway. Inhibiting mTORC1 with rapamycin reversed this effect, indicating a key molecular mechanism.

Area of Science:

  • Oncology
  • Molecular Biology
  • Cell Biology

Background:

  • Tumor microenvironments involve complex cell-cell interactions.
  • Osteoblasts play a role in bone remodeling and cancer metastasis.
  • Semaphorin3a (Sema3a) is implicated in various biological processes, including neuronal guidance and bone metabolism.

Purpose of the Study:

  • To investigate the effect of Lewis Lung Carcinoma (LLC) conditioned medium on osteoblast gene expression.
  • To determine the role of mammalian target of rapamycin complex 1 (mTORC1) signaling in mediating tumor cell-osteoblast interactions.

Main Methods:

  • Treatment of osteoblast-like MC3T3-E1 cells with LLC conditioned medium.
  • Measurement of Semaphorin3a (Sema3a) mRNA expression.
  • Assessment of mammalian target of rapamycin complex 1 (mTORC1) activity.
  • Pharmacological inhibition of mTORC1 using rapamycin.

Main Results:

  • LLC conditioned medium significantly down-regulated Sema3a mRNA expression in MC3T3-E1 cells.
  • LLC conditioned medium increased mTORC1 activity in MC3T3-E1 cells.
  • Rapamycin treatment counteracted the down-regulation of Sema3a mRNA induced by LLC conditioned medium.

Conclusions:

  • Lewis Lung Carcinoma cells decrease Sema3a mRNA expression in osteoblasts.
  • This down-regulation is dependent on the activation of the mTORC1 signaling pathway.
  • Targeting the mTORC1 pathway may represent a therapeutic strategy in bone-related cancer complications.
Keywords:
Semaphorin-3amTORC1osteoblast

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