Proteomic Analysis of Proton Beam Irradiated Human Melanoma Cells

Abstract

Proton beam irradiation is a form of advanced radiotherapy providing superior distributions of a low LET radiation dose relative to that of photon therapy for the treatment of cancer. Even though this clinical treatment has been developing for several decades, the proton radiobiology critical to the optimization of proton radiotherapy is far from being understood. Proteomic changes were analyzed in human melanoma cells treated with a sublethal dose (3 Gy) of proton beam irradiation. The results were compared with untreated cells. Two-dimensional electrophoresis was performed with mass spectrometry to identify the proteins. At the dose of 3 Gy a minimal slowdown in proliferation rate was seen, as well as some DNA damage. After allowing time for damage repair, the proteomic analysis was performed. In total 17 protein levels were found to significantly (more than 1.5 times) change: 4 downregulated and 13 upregulated. Functionally, they represent four categories: (i) DNA repair and RNA regulation (VCP, MVP, STRAP, FAB-2, Lamine A/C, GAPDH), (ii) cell survival and stress response (STRAP, MCM7, Annexin 7, MVP, Caprin-1, PDCD6, VCP, HSP70), (iii) cell metabolism (TIM, GAPDH, VCP), and (iv) cytoskeleton and motility (Moesin, Actinin 4, FAB-2, Vimentin, Annexin 7, Lamine A/C, Lamine B). A substantial decrease (2.3 x) was seen in the level of vimentin, a marker of epithelial to mesenchymal transition and the metastatic properties of melanoma.

α-Actinin-4 Is Required for Amoeboid-type Invasiveness of Melanoma Cells

“…In fact, ACTN4 is one of the most up-regulated proteins in the dermis when comparing melanoma-invaded with non-involved regions of skin. Of interest, when melanoma cells are activated by low dose proton beam irradiation, ACTN4 expression is increased (10). These findings implicate ACTN4 as being involved in the invasion and metastasis of melanoma.…”

Human papillomavirus status and the relative biological effectiveness of proton radiotherapy in head and neck cancer cells

“…10 Proton therapy has shown promise in the treatment of HNSCC. 12,13 The RBE of proton therapy is defined as the ratio of the biological effectiveness of protons relative to that of X-rays for the same amount of absorbed energy. 12,13 The RBE of proton therapy is defined as the ratio of the biological effectiveness of protons relative to that of X-rays for the same amount of absorbed energy.…”

“…11 However, whether the dosimetric advantages of proton therapy can translate into demonstrable clinical benefit for HNSCC remains unclear, in part because of variations in the relative biological effectiveness (RBE) of protons in different types of cells or tissues. 12,13 The RBE of proton therapy is defined as the ratio of the biological effectiveness of protons relative to that of X-rays for the same amount of absorbed energy. In current clinical practice, the RBE of proton therapy has been assumed to be 1.1 regardless of tumor type.…”

The Highlighted Role of GAPDH and Nitric-Oxide Synthase Regulator Activity in Proton Beam Irradiated Melanoma BLM Cells

“…irradiation by a proton beam, is a potential tumor treatment method in terms of appropriate targeting and dosage spreading. 4 The clinical outcome of this approach implies that the survival rate of this treatment is very acceptable and the mechanism by which this method works is recognized as the reduction of ocular toxic materials. In addition, it is estimated that only 7%-10% of these patients treated with proton irradiation require eye removal.…”

“…7 Understanding the mechanisms by which radiotherapy impacts on the tumor efficiently could be better recognized by high throughput methods such as proteomics. 4 Proteomics introduces biomarkers which are important in the underlying mechanism of treatment procedure. These proteins are differentially expressed in the subject receiving the treatment.…”