Overexpression of ADAM9 in oral squamous cell carcinoma

Abstract

Abstract. Overexpression of a disintegrin and metalloproteinase 9 (ADAM9) has been shown in various types of cancer. Some studies have reported inconclusive findings regarding chromosomal aberrations in the ADAM9-containing region and ADAM9 expression in oral cancer. Therefore, in this study, ADAM9 protein expression was determined and compared between oral squamous cell carcinoma (OSCC) and normal oral tissues, and between oral cancer cell lines and human oral keratinocytes (HOKs). In total, 34 OSCC and 10 healthy paraffin-embedded tissue sections were probed with an anti-ADAM9 antibody, and the immunohistochemical score was determined by multiplying the percentage of positively stained cells with the intensity score. Four different oral cancer and eight independent HOK cell lines were cultured, and the expression of membrane ADAM9 and active ADAM9 at 84 kDa in these cell lines was assayed by flow cytometry and western blot hybridization, respectively. The results showed that the median immunohistochemical score of ADAM9 expression in OSCC tissues was significantly greater than that in normal tissues (P<0.001). Furthermore, among OSCC cases, intense staining of ADAM9 expression was detected in well-differentiated and in moderately-differentiated OSCC; ADAM9 expression was also correlated with an increased degree of cell differentiation (r=0.557; P=0.001). Expression of membrane ADAM9 was present in 3/4 cancer cell lines. Expression of active ADAM9 varied among all the tested cell lines, but significantly higher ADAM9 expression was present in certain cancer cell lines than those in HOKs (P<0.05). In summary, ADAM9 expression is enhanced in OSCC and oral cancer cell lines, suggesting its role in the pathogenesis of oral cancer. Similar to the overexpression of ADAM9 in well-differentiated prostate cancer, high degrees of ADAM9 expression have also been observed in well-differentiated OSCC.

Cancer‑associated fibroblast stimulates cancer cell invasion in an interleukin‑1 receptor (IL‑1R)‑dependent manner

“…The increased Transwell invasion by CM-CAF was abrogated by neutralization of ADAM 9 or Kallikrein 11. ADAM 9 is known as metalloprotease disintegrin cysteine-rich protein 9 or meltrin β. Overexpression of ADAM 9 has been identified in a variety of cancer types, including breast cancer, renal cancer, prostate cancer, skin cancer, uterine cervical cancer, hepatocellular carcinoma, non-small cell lung cancer, colon cancer, gastric cancer, esophageal cancer, and head and neck squamous cell carcinoma (HNSCC) (21). ADAM 9 is induced by oxidative stress, such as intracellular reactive oxygen species (ROS) and/or hydrogen peroxide, thereby supporting prostate cancer cell survival and progression (22).…”

“…Enhanced ADAM 9 expression has been reported in oral squamous cell carcinoma (OSCC) compared to normal oral tissue. Moreover, a high degree of ADAM 9 expression has been observed in well-differentiated OSCC (21). Kallikrein 11 (KLK11) is a secreted type of serine protease, highly expressed in many tissues including brain, skin, salivary gland, stomach, prostate, and intestine (23).…”

O‐GlcNAcylation in oral squamous cell carcinoma

“…Four oral cancer cell lines, HN5, HN6, HN15, and HN008, and 8 normal HOK cell lines were obtained from our recent study. 28 Figure 2B), whereas median IHC scores were significantly higher in OSCC than normal tissues for p-Akt ser473 (P < .01; Figure 2C) and p-EGFR tyr1173 expressions (P < .001; Figure 2D).…”

“…Four oral cancer cell lines, HN5, HN6, HN15, and HN008, and 8 normal HOK cell lines were obtained from our recent study . Primary HOKs were isolated from normal non‐inflamed gingival biopsies overlying bony impaction of third molars of 8 healthy donors.…”

“…All cell lines were cultured in serum‐free keratinocyte growth medium (Lonza, Walkersville, MD, USA) at 37°C in a humidified chamber with 5% CO 2 until 80% cell confluence. A 20‐μg quantity of whole cell lysates extracted in radio‐immunoprecipitation assay buffer was boiled at 100°C for 5 minutes, resolved on 7.5% SDS‐PAGE, and blotted onto nitrocellulose membranes (Bio‐Rad Laboratories, Hercules, CA, USA). The membranes were blocked with 5% non‐fat dry milk (Santa Cruz Biotechnology) in 0.1% Tween‐TBS for 1 hour and incubated with the antibody against O ‐GlcNAc (1:1000), p‐ser/thr/tyr (1:500), or beta‐actin (1:1000) at 4°C overnight.…”