Limits...
Keloid-derived keratinocytes acquire a fibroblast-like appearance and an enhanced invasive capacity in a hypoxic microenvironment in vitro.

Ma X, Chen J, Xu B, Long X, Qin H, Zhao RC, Wang X - Int. J. Mol. Med. (2015)

Bottom Line: The high expression of mesenchymal markers, such as as vimentin and fibronectin was confirmed, as well as the reduced expression of E-cadherin and zonula occludens-1 (ZO-1) during this process by detection at the protein and mRNA level.Moreover, siRNA targeting HIF-1α reversed the changes which had occurred in the morphology of the keratinocytes (cells had acquired a fibroblast-like appearance) and suppressed the invasive ability of the keratinocytes.In conclusion, the present findings demonstrate that the hypoxia/HIF-1α microenvironment provides a favorable environment for keloid-derived keratinocytes to adopt a fibroblast-like appearance through EMT.

View Article: PubMed Central - PubMed

Affiliation: Department of Plastic and Reconstructive Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, P.R. China.

ABSTRACT
A keloid scar is an overgrowth of dense fibrous tissue that develops around a wound. These scars are raised scars that spread beyong the margins of the orinigal wound to normal skin by invasion. Keloid tissue consists of both an epithelium and dermal fibroblasts. Recent studies have primarily focused on keloid fibroblasts; however, the precise role of keratinocytes in the invasion process of keloids remains to be identified. Hypoxia is a typical characteristic of keloid scars, as well as other solid tumors. The expression of the transcription factor, hypoxia-inducible factor-1α (HIF-1α), is mainly induced by hypoxia and is known for its ability to induce proliferative and transformative changes in cells; its expression has been shown to correlate with tumor invasion and metastasis. In the present study, we used immunohistochemistry, fluorescence staining and western blot analysis and demonstrated that HIF-1α was highly expressed in both the epithelial layer of keloid tissue specimens and in hypoxia-exposed keratinocytes, which suggested that the keloid keratinocytes underwent epithelial-to-mesenchymal transition (EMT) in vitro. The high expression of mesenchymal markers, such as as vimentin and fibronectin was confirmed, as well as the reduced expression of E-cadherin and zonula occludens-1 (ZO-1) during this process by detection at the protein and mRNA level. Moreover, siRNA targeting HIF-1α reversed the changes which had occurred in the morphology of the keratinocytes (cells had acquired a fibroblast-like appearance) and suppressed the invasive ability of the keratinocytes. In conclusion, the present findings demonstrate that the hypoxia/HIF-1α microenvironment provides a favorable environment for keloid-derived keratinocytes to adopt a fibroblast-like appearance through EMT. This transition may be responsible for the enhanced capacity of keloid keratinocytes to invade, allowing the keloids to extend beyond the wound margin.

Show MeSH

Related in: MedlinePlus

Cell invasiveness investigated by Matrigel co-culture chambers. The invasive cells were fixed and stained with Crystal violet. (a) Invasion of keloid keratinocytes under normoxic conditions (21% O2). (b–d) Invasion of keloid keratinocytes cultured under hypoxia conditions (1% O2) for 12, 24 and 36 h, respectively. (e) Columns indicate the optical density (OD) of Crystal violet eluted from the invading keloid keratinocytes under normoxic and hypoxic culture conditions (12, 24 and 36 h). *P<0.05 vs. keratinocytes under normoxic conditions (21% O2). Bars represent the means ± SD of 3 independent experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4380122&req=5

f7-ijmm-35-05-1246: Cell invasiveness investigated by Matrigel co-culture chambers. The invasive cells were fixed and stained with Crystal violet. (a) Invasion of keloid keratinocytes under normoxic conditions (21% O2). (b–d) Invasion of keloid keratinocytes cultured under hypoxia conditions (1% O2) for 12, 24 and 36 h, respectively. (e) Columns indicate the optical density (OD) of Crystal violet eluted from the invading keloid keratinocytes under normoxic and hypoxic culture conditions (12, 24 and 36 h). *P<0.05 vs. keratinocytes under normoxic conditions (21% O2). Bars represent the means ± SD of 3 independent experiments.

Mentions: The stimulating effect of hypoxia on the invasion of keloid-derived keratinocytes was investigated under hypoxic culture conditions. The keratinocytes were cultured under hypoxic conditions (1% O2) for 12, 24 and 36 h, and compared to the cells cultured under normoxic conditions. The number of migrated keratinocytes at 12, 24, and 36 h of culture under hypoxic conditions markedly increased by 9-, 15.8- and 32-fold, respectively compared to the normoxic controls (P<0.01, 0.01 and 0.01, respectively) (Fig. 7). In addition, the invasive capacity of the cells was compared between the HIF-1α siRNA-transfected keratinocytes and the hypoxia-exposed keratinocytes. The results revealed a significant decrease in the number of infiltrated cells by 91.3±1.2% in the HIF-1α siRNA-transfected group (P<0.05) (Fig. 8). As a result, hypoxia/HIF-1α may enhance the invasive capacity of keloid keratinocytes.


Keloid-derived keratinocytes acquire a fibroblast-like appearance and an enhanced invasive capacity in a hypoxic microenvironment in vitro.

Ma X, Chen J, Xu B, Long X, Qin H, Zhao RC, Wang X - Int. J. Mol. Med. (2015)

Cell invasiveness investigated by Matrigel co-culture chambers. The invasive cells were fixed and stained with Crystal violet. (a) Invasion of keloid keratinocytes under normoxic conditions (21% O2). (b–d) Invasion of keloid keratinocytes cultured under hypoxia conditions (1% O2) for 12, 24 and 36 h, respectively. (e) Columns indicate the optical density (OD) of Crystal violet eluted from the invading keloid keratinocytes under normoxic and hypoxic culture conditions (12, 24 and 36 h). *P<0.05 vs. keratinocytes under normoxic conditions (21% O2). Bars represent the means ± SD of 3 independent experiments.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4380122&req=5

f7-ijmm-35-05-1246: Cell invasiveness investigated by Matrigel co-culture chambers. The invasive cells were fixed and stained with Crystal violet. (a) Invasion of keloid keratinocytes under normoxic conditions (21% O2). (b–d) Invasion of keloid keratinocytes cultured under hypoxia conditions (1% O2) for 12, 24 and 36 h, respectively. (e) Columns indicate the optical density (OD) of Crystal violet eluted from the invading keloid keratinocytes under normoxic and hypoxic culture conditions (12, 24 and 36 h). *P<0.05 vs. keratinocytes under normoxic conditions (21% O2). Bars represent the means ± SD of 3 independent experiments.
Mentions: The stimulating effect of hypoxia on the invasion of keloid-derived keratinocytes was investigated under hypoxic culture conditions. The keratinocytes were cultured under hypoxic conditions (1% O2) for 12, 24 and 36 h, and compared to the cells cultured under normoxic conditions. The number of migrated keratinocytes at 12, 24, and 36 h of culture under hypoxic conditions markedly increased by 9-, 15.8- and 32-fold, respectively compared to the normoxic controls (P<0.01, 0.01 and 0.01, respectively) (Fig. 7). In addition, the invasive capacity of the cells was compared between the HIF-1α siRNA-transfected keratinocytes and the hypoxia-exposed keratinocytes. The results revealed a significant decrease in the number of infiltrated cells by 91.3±1.2% in the HIF-1α siRNA-transfected group (P<0.05) (Fig. 8). As a result, hypoxia/HIF-1α may enhance the invasive capacity of keloid keratinocytes.

Bottom Line: The high expression of mesenchymal markers, such as as vimentin and fibronectin was confirmed, as well as the reduced expression of E-cadherin and zonula occludens-1 (ZO-1) during this process by detection at the protein and mRNA level.Moreover, siRNA targeting HIF-1α reversed the changes which had occurred in the morphology of the keratinocytes (cells had acquired a fibroblast-like appearance) and suppressed the invasive ability of the keratinocytes.In conclusion, the present findings demonstrate that the hypoxia/HIF-1α microenvironment provides a favorable environment for keloid-derived keratinocytes to adopt a fibroblast-like appearance through EMT.

View Article: PubMed Central - PubMed

Affiliation: Department of Plastic and Reconstructive Surgery, Peking Union Medical College Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing 100730, P.R. China.

ABSTRACT
A keloid scar is an overgrowth of dense fibrous tissue that develops around a wound. These scars are raised scars that spread beyong the margins of the orinigal wound to normal skin by invasion. Keloid tissue consists of both an epithelium and dermal fibroblasts. Recent studies have primarily focused on keloid fibroblasts; however, the precise role of keratinocytes in the invasion process of keloids remains to be identified. Hypoxia is a typical characteristic of keloid scars, as well as other solid tumors. The expression of the transcription factor, hypoxia-inducible factor-1α (HIF-1α), is mainly induced by hypoxia and is known for its ability to induce proliferative and transformative changes in cells; its expression has been shown to correlate with tumor invasion and metastasis. In the present study, we used immunohistochemistry, fluorescence staining and western blot analysis and demonstrated that HIF-1α was highly expressed in both the epithelial layer of keloid tissue specimens and in hypoxia-exposed keratinocytes, which suggested that the keloid keratinocytes underwent epithelial-to-mesenchymal transition (EMT) in vitro. The high expression of mesenchymal markers, such as as vimentin and fibronectin was confirmed, as well as the reduced expression of E-cadherin and zonula occludens-1 (ZO-1) during this process by detection at the protein and mRNA level. Moreover, siRNA targeting HIF-1α reversed the changes which had occurred in the morphology of the keratinocytes (cells had acquired a fibroblast-like appearance) and suppressed the invasive ability of the keratinocytes. In conclusion, the present findings demonstrate that the hypoxia/HIF-1α microenvironment provides a favorable environment for keloid-derived keratinocytes to adopt a fibroblast-like appearance through EMT. This transition may be responsible for the enhanced capacity of keloid keratinocytes to invade, allowing the keloids to extend beyond the wound margin.

Show MeSH
Related in: MedlinePlus