Archives

  • 2018-07
  • 2018-10
  • 2018-11
  • 2019-04
  • 2019-05
  • 2019-06
  • 2019-07
  • 2019-08
  • 2019-09
  • 2019-10
  • 2019-11
  • 2019-12
  • 2020-01
  • 2020-02
  • 2020-03
  • 2020-04
  • 2020-05
  • 2020-06
  • 2020-07
  • 2020-08
  • 2020-09
  • 2020-10
  • 2020-11
  • 2020-12
  • 2021-01
  • 2021-02
  • 2021-03
  • 2021-04
  • 2021-05
  • 2021-06
  • 2021-07
  • 2021-08
  • 2021-09
  • 2021-10
  • 2021-11
  • 2021-12
  • 2022-01
  • 2022-02
  • 2022-03
  • 2022-04
  • 2022-05
  • 2022-06
  • 2022-07
  • 2022-08
  • 2022-09
  • 2022-10
  • 2022-11
  • 2022-12
  • 2023-01
  • 2023-02
  • 2023-03
  • 2023-04
  • 2023-05
  • 2023-06
  • 2023-07
  • 2023-08
  • 2023-09
  • 2023-10
  • 2023-11
  • 2023-12
  • 2024-01
  • 2024-02
  • 2024-03
  • br Conflict of Interest Both GM and BDH

    2022-08-12


    Conflict of Interest Both GM and BDH are shareholders in Caldan Therapeutics, a company exploring potential novel treatments for type 2 diabetes.
    Acknowledgments Work described herein was supported by Biotechnology and Biological Sciences Research Council [grant BB/K019864/1)] (to GM) and [grant BB/K019856/1] (to ABT).
    Introduction G-protein-coupled receptors (GPCRs) are seven-transmembrane receptors and exhibit several biological responses through binding of specific ligands [1], [2]. G-protein-coupled receptor 120 (GPR120) and GPR40 are identified as GPCRs for free fatty acids (FFAs) which are essential dietary nutrients and energy sources. FFAs are classified by the length of carbon chains. GPR120 and GPR40 are activated by long- and medium-chain FFAs [3], [4]. The distribution of GPR120 and GPR40 expressions is not uniform. For instance, the high expression levels of GPR120 were found in the lung, gastrointestinal tract, adipocytes and macrophages, while GPR40 was detected in pancreatic islets [5], [6], [7]. Moreover, GPR40 was highly expressed in insulinoma cells, but not in glucagonoma Pertussis Toxin [8]. Therefore, it is considered that GPR120 and GPR40 are potent target molecules for the control of diabetes, obesity and cardiovascular disorders. In fact, GPR120 and GPR40 regulate hormone secretion from the pancreas and digestive tract, and stimulate anti-inflammatory effects [5], [9], [10], [11], [12]. It has been reported that GPR120 and GPR40 were involved in the pathogenesis of cancer cells. The high expression levels of GPR120 were observed in human colorectal carcinomas, compared with normal tissues. The cell motile and angiogenic activities of colon cancer cells were increased by GPR120 [13]. GPR40 negatively regulated the cell motile and invasive activities of fibrosarcoma cells which unexpressed GPR120 [14]. In contrast, GPR120 inhibited and GPR40 stimulated cellular functions of lung cancer cells [15].
    Materials and methods
    Results and discussion GPR120 and GPR40 showed diverse effects on the regulation of cellular functions in cancer cells. In colon cancer cells, the cell motility and angiogenesis were activated by GPR120 [13]. GPR120 stimulated and GPR40 reduced the cell motility, invasion and tumorigenicity of pancreatic cancer cells [17]. In contrast, GPR120 suppressed and GPR40 elevated the cell motile and invasive activities of lung cancer cells [15]. In addition, the cell motile activity of liver epithelial cells treated with chemical carcinogens was regulated through induction of GPR120 and GPR40 [18], [19]. In the present study, we examined the roles of GPR120 and GPR40 in the enhancement of cell motile activity of MG-63 cells, using highly migratory cells. First, to assess the effects of GPR120 and GPR40 on the cell motile activity of MG-63 cells, GPR120 knockdown (MG-120) cells were generated. The expression patterns of GPR120 and GPR40 genes by semi-quantitative RT-PCR analysis are shown in Fig. 1A. The efficiency of GPR120 knockdown was also evaluated by quantitative real-time RT-PCR analysis (Fig. 1B). The cell motile activity of MG-120 cells was significantly lower than that of MG-R (control) cells. Treatment of GW9508 reduced the cell motile activity of MG-120 cells, whereas the cell motile activity of MG-R cells was increased by GW9508 (Fig. 1C). Since GW9508 acts as an agonist of GPR120 and GPR40 [20], [21], these findings indicated that GPR120 stimulated the cell motile activity of MG-63 cells. In addition, to assess the effects of GPR120 and GPR40 on the cell motile activity of other osteosarcoma cells, GPR120 knockdown (COS-120) cells were also generated from rat osteosarcoma COS1NR cells [22]. COS1NR cells endogenously expressed GPR120 and GPR40 genes (data not shown). In the presence of GW9508, the cell motile activity of COS-120 cells was significantly lower than that of COS-R (control) cells, similar as observed with MG-63 cells (Fig. 1D). To investigate an involvement of GPR120 and GPR40 in the enhancement of cell motile activity of MG-63 cells, highly migratory (MG63-R7) cells were established from MG-63 cells (Fig. 2A). The expression level of GPR120 gene was significantly higher in MG63-R7 cells than in MG-63 cells, while no change of GPR40 expressions was observed (Fig. 2B). The cell growth rate of MG63-R7 cells was significantly lower than that of MG-63 cells (Fig. 2C). GW9508 had no impact on the cell growth activities of both cells (Fig. 2D). The cell motile activity of MG63-R7 cells was approximately 200 times higher than that of MG-63 cells. GW9508 increased the cell motile activities of both cells (Fig. 3A and B). In cell invasion assay, MG63-R7 cells showed the high invasive activity, compared with MG-63 cells. The invasive activity of MG63-R7 cells was increased by GW9508, but not MG-63 cells (Fig. 3C). On the other hand, the activation of MMP-2 was significantly lower in MG63-R7 cells than in MG-63 cells. GW9508 had no impact on MMP-2 activations. No activation of MMP-9 was not detected in both cells (Fig. 3D and E). It is considered that MMP-2 and MMP-9 activations facilitate tumor progression, including invasion and metastasis [23], [24]. Since MG63-R7 cells indicated the low MMP-2 activation, it seems that the high cell invasive rate observed in the cell invasion assay may be due to the intrinsic cell motile activity of MG63-R7 cells.