Cell Stress and Chaperones

, Volume 23, Issue 6, pp 1283–1294 | Cite as

Palmitic acid induces human osteoblast-like Saos-2 cell apoptosis via endoplasmic reticulum stress and autophagy

  • Lei YangEmail author
  • Gaopeng Guan
  • Lanjie Lei
  • Qizhuang Lv
  • Shengyuan Liu
  • Xiuwen Zhan
  • Zhenzhen Jiang
  • Xiang GuEmail author
Original Paper


Palmitic acid (PA) is the most common saturated long-chain fatty acid in food that causes cell apoptosis. However, little is known about the molecular mechanisms of PA toxicity. In this study, we explore the effects of PA on proliferation and apoptosis in human osteoblast-like Saos-2 cells and uncover the signaling pathways involved in the process. Our study showed that endoplasmic reticulum (ER) stress and autophagy are involved in PA-induced Saos-2 cell apoptosis. We found that PA inhibited the viability of Saos-2 cells in a dose- and time-dependent manner. At the same time, PA induced the expression of ER stress marker genes (glucose-regulated protein 78 (GRP78) and CCAAT/enhancer binding protein homologous protein (CHOP)), altered autophagy-related gene expression (microtubule-associated protein 1 light chain 3 (LC3), ATG5, p62, and Beclin), promoted apoptosis-related gene expression (Caspase 3 and BAX), and affected autophagic flux. Inhibiting ER stress with 4-PBA diminished the PA-induced cell apoptosis, activated autophagy, and increased the expression of Caspase 3 and BAX. Inhibiting autophagy with 3-MA attenuated the PA and ER stress-induced cell apoptosis and the apoptosis-related gene expression (Caspase 3 and BAX), but seemed to have no obvious effects on ER stress, although the CHOP expression was downregulated. Taken together, our results suggest that PA-induced Saos-2 cell apoptosis is activated via ER stress and autophagy, and the activation of autophagy depends on the ER stress during this process.


Palmitic acid Endoplasmic reticulum stress Autophagy Saos-2 cells 


Funding information

This research study was funded by the National Natural Science Foundation of China (No. 81660152) and Doctoral Research Start-Up Foundation of Jiujiang University (No. 8879522).

Compliance with ethical standards

Conflict of interest

The authors declare that they have no conflict of interest.

Supplementary material

12192_2018_936_MOESM1_ESM.docx (16 kb)
Supplementary Table 1 (DOCX 16 kb)
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Fig. S1

The morphology of Saos-2 cells after treatment with different doses of PA (0–800 μM) for 24 h. (PNG 18533 kb)

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High resolution image (TIF 26708 kb)
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Fig. S2

Effects of PA on ER Stress, autophagy, and apoptosis related protein expression. (A) The expression of GRP78 and CHOP in Saos-2 cells after treatment with different doses of PA (0–800 μM) for 24 h; (B) The expression of GRP78 and CHOP after treatment with 200 μM PA for different times (0–48 h); (C) The expression of Beclin1, LC3, ATG5 and p62 in Saos-2 cells after treatment with different doses of PA (0–800 μM) for 24 h; (D) The expression of Beclin1, LC3, ATG5 and p62 after treatment with 200 μM PA for different times (0–48 h); (E) The expression of BAX in Saos-2 cells after treatment with different dose of PA (0–800 μM) for 24 h; (F) The expression of BAX after treatment with 200 μM PA for different times (0–48 h). (PNG 395 kb)

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High resolution image (TIF 810 kb)
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Fig. S3

The related protein expression of ER Stress, autophagy, and apoptosis in different treatment groups. (A) Effect of 4-PBA in PA-treated Saos-2 cells; (B) Effect of 3-MA in PA-treated Saos-2 cells; (C) Effect of 3-MA in TG-treated Saos-2 cells. (PNG 1311 kb)

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Fig. S4

Amplified Fig. 5D. (PNG 2133 kb)

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High resolution image (TIF 2977 kb)
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Fig. S5

Amplified Fig. 6D. (PNG 1843 kb)

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Fig. S6

Amplified Fig. 7D. (PNG 4088 kb)

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High resolution image (TIF 7559 kb)


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Copyright information

© Cell Stress Society International 2018

Authors and Affiliations

  1. 1.College of Basic MedicalJiujiang UniversityJiujiangChina
  2. 2.Key Laboratory of System Bio-medicine of Jiangxi ProvinceJiujiang UniversityJiujiangChina
  3. 3.Affiliated Hospital of Jiujiang UniversityJiujiang UniversityJiujiangChina
  4. 4.Medicine Graduate SchoolNanchang UniversityNanchangChina
  5. 5.College of Biology & PharmacyYulin Normal UniversityYulinChina

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