Biological characteristics of gene expression features in pancreatic cancer cells induced by proton and X-ray irradiation

The characteristic of stem-related genes with pancreatic carcinoma cell after irradiation

Purpose

To investigate stem-related differentially expressed genes (DEGs) and their potential mechanism in pancreatic cancer cells (MIAPaCa-2) exposed to x-ray and proton radiation, as well as how these factors affected the prognosis of patients with pancreatic adenocarcinoma (PADC).

Methods

The stem-related DEGs were screened using the online tool Stemchecker after protons and x-rays were used to irradiate MIAPaCa-2 cells. Analysis was done on the probable processes and prognostic significance of the DEGs in PAC patients.

Results

Four datasets containing 401 DEGs were filtered, and the stem-related DEGs for each irradiation type indicated a variety of radiobiological characteristics. In pancreatic cancer cells, a number of stem-related DEGs may serve as biomarkers of radiation effects. Patients with pancreatic cancer demonstrated predictive significance for GRB7, B2M, and PMAIP1.

Conclusions

MIAPaCa-2 cells exposed to x-rays and protons repeatedly displayed heterogeneous expression of stem-related DEGs involved in complex radiosensitivity, radio-resistance, and radio-induced mortality pathways. GRB7 and B2M were considered potential radiation sensitivity indicators for pancreatic cancer.

Radiation Type- and Dose-Specific Transcriptional Responses across Healthy and Diseased Mammalian Tissues

Ionizing radiation (IR) is a genuine genotoxic agent and a major modality in cancer treatment. IR disrupts DNA sequences and exerts mutagenic and/or cytotoxic properties that not only alter critical cellular functions but also impact tissues proximal and distal to the irradiated site. Unveiling the molecular events governing the diverse effects of IR at the cellular and organismal levels is relevant for both radiotherapy and radiation protection. Herein, we address changes in the expression of mammalian genes induced after the exposure of a wide range of tissues to various radiation types with distinct biophysical characteristics. First, we constructed a publicly available database, termed RadBioBase, which will be updated at regular intervals. RadBioBase includes comprehensive transcriptomes of mammalian cells across healthy and diseased tissues that respond to a range of radiation types and doses. Pertinent information was derived from a hybrid analysis based on stringent literature mining and transcriptomic studies. An integrative bioinformatics methodology, including functional enrichment analysis and machine learning techniques, was employed to unveil the characteristic biological pathways related to specific radiation types and their association with various diseases. We found that the effects of high linear energy transfer (LET) radiation on cell transcriptomes significantly differ from those caused by low LET and are consistent with immunomodulation, inflammation, oxidative stress responses and cell death. The transcriptome changes also depend on the dose since low doses up to 0.5 Gy are related with cytokine cascades, while higher doses with ROS metabolism. We additionally identified distinct gene signatures for different types of radiation. Overall, our data suggest that different radiation types and doses can trigger distinct trajectories of cell-intrinsic and cell-extrinsic pathways that hold promise to be manipulated toward improving radiotherapy efficiency and reducing systemic radiotoxicities.

Charged Particle Irradiation for Pancreatic Cancer: A Systematic Review of In Vitro Studies

Purpose

Given the higher precision accompanied by optimized sparing of normal tissue, charged particle therapy was thought of as a promising treatment for pancreatic cancer. However, systematic preclinical studies were scarce. We aimed to investigate the radiobiological effects of charged particle irradiation on pancreatic cancer cell lines.

Methods

A systematic literature search was performed in EMBASE (OVID), Medline (OVID), and Web of Science databases. Included studies were in vitro English publications that reported the radiobiological effects of charged particle irradiation on pancreatic cancer cells.

Results

Thirteen carbon ion irradiation and seven proton irradiation in vitro studies were included finally. Relative biological effectiveness (RBE) values of carbon ion irradiation and proton irradiation in different human pancreatic cancer cell lines ranged from 1.29 to 4.5, and 0.6 to 2.1, respectively. The mean of the surviving fraction of 2 Gy (SF2) of carbon ion, proton, and photon irradiation was 0.18 ± 0.11, 0.48 ± 0.11, and 0.57 ± 0.13, respectively. Carbon ion irradiation induced more G2/M arrest and a longer-lasting expression of γH2AX than photon irradiation. Combination therapies enhanced the therapeutic effects of pancreatic cell lines with a mean standard enhancement ratio (SER) of 1.66 ± 0.63 for carbon ion irradiation, 1.55 ± 0.27 for proton irradiation, and 1.52 ± 0.30 for photon irradiation. Carbon ion irradiation was more effective in suppressing the migration and invasion than photon irradiation, except for the PANC-1 cells.

Conclusions

Current in vitro evidence demonstrates that, compared with photon irradiation, carbon ion irradiation offers superior radiobiological effects in the treatment of pancreatic cancer. Mechanistically, high-LET irradiation may induce complex DNA damage and ultimately promote genomic instability and cell death. Both carbon ion irradiation and proton irradiation confer similar sensitization effects in comparison with photon irradiation when combined with chemotherapy or targeted therapy.

Ion Accelerator Facility of the Wakasa Wan Energy Research Center for the Study of Irradiation Effects on Space Electronics

The core facility of the Wakasa Wan Energy Research Center (WERC) consists of three ion accelerators: a synchrotron, a tandem accelerator and an ion-implanter. Research on the irradiation effects using these accelerators has been performed on space electronics such as solar cells, radiation detectors, image sensors and LSI circuits. In this report, the accelerator facility and ion-irradiation apparatuses at WERC are introduced, focusing on the research on irradiation effects on space electronics. Then, some recent results are summarized.

Radioactive 125I seed implantation for pancreatic cancer with unexpected liver metastasis: A preliminary experience with 26 patients

BACKGROUND

Preoperative diagnosis rate of pancreatic cancer has increased year by year. The prognosis of pancreatic cancer patients with unexpected liver metastasis found by intraoperative exploration is very poor, and there is no effective and unified treatment strategy.

AIM

To evaluate the therapeutic effect of radioactive ¹²⁵I seed implantation for pancreatic cancer patients with unexpected liver metastasis.

METHODS

The demographics and perioperative outcomes of patients who underwent ¹²⁵I seed implantation to treat pancreatic cancer with unexpected liver metastasis between January 1, 2017 and June 1, 2019 were retrospectively analyzed. During the operation, ¹²⁵I seeds were implanted into the pancreatic tumor under the guidance of intraoperative ultrasound, with a spacing of 1.5 cm and a row spacing of 1.5 cm. For patients with obstructive jaundice and digestive tract obstruction, choledochojejunostomy and gastroenterostomy were performed simultaneously. After operation, the patients were divided into a non-chemotherapy group and a chemotherapy group that received gemcitabine combined with albumin-bound paclitaxel treatment.

RESULTS

Preoperative imaging evaluation of all patients in this study showed that the tumor was resectable without liver metastasis. There were 26 patients in this study, including 18 males and 8 females, aged 60.5 ± 9.7 years. The most common tumor site was the pancreatic head (17, 65.4%), followed by the pancreatic neck and body (6, 23.2%) and pancreatic tail (3, 11.4%). Fourteen patients (53.8%) underwent palliative surgery and postoperative pain relief occurred in 22 patients (84.6%). The estimated blood loss in operation was 148.3 ± 282.1 mL and one patient received blood transfusion. The postoperative hospital stay was 7.6 ± 2.8 d. One patient had biliary fistula, one had pancreatic fistula, and all recovered after conservative treatment. After operation, 7 patients received chemotherapy and 19 did not. The 1-year survival rate was significantly higher in patients who received chemotherapy than in those who did not (68.6% vs 15.8%, P = 0.012). The mean overall survival of patients in the chemotherapy group and non-chemotherapy group was 16.3 mo and 10 mo, respectively (χ² = 7.083, P = 0.008).

CONCLUSION

Radioactive ¹²⁵I seed implantation combined with postoperative chemotherapy can prolong the survival time and relieve pain of pancreatic cancer patients with unexpected liver metastasis.

Radioactive 125I seed implantation for locally advanced pancreatic cancer: A retrospective analysis of 50 cases

BACKGROUND

Pancreatic cancer is one of the common malignant tumors of the digestive system, and radical resection is the first choice of treatment for pancreatic cancer. If patients with locally advanced pancreatic cancer cannot be treated in time and effectively, their disease often develops rapidly and their survival period is very short.

AIM

To evaluate the therapeutic effect of ¹²⁵I seed implantation in patients with locally advanced pancreatic cancer.

METHODS

The demographics and perioperative outcomes of a consecutive series of patients who underwent ¹²⁵I seed implantation to treat locally advanced pancreatic cancer between January 1, 2017 and June 30, 2019 were retrospectively analyzed. According to the results of preoperative computed tomography or magnetic resonance imaging, the treatment planning system was used to determine the area and number of ¹²⁵I seeds implanted. During the operation, ¹²⁵I seeds were implanted into the tumor under the guidance of intraoperative ultrasound, with a spacing of 1.5 cm and a row spacing of 1.5 cm. For patients with obstructive jaundice and digestive tract obstruction, choledochojejunostomy and gastroenterostomy were performed simultaneously. After operation, the patients were divided into a non-chemotherapy group and a chemotherapy group that received gemcitabine combined with albumin-bound paclitaxel treatment.

RESULTS

Among the 50 patients, there were 29 males and 21 females, with a mean age of 56.9 ± 9.8 years. The main reason for the failure of radical resection was superior mesenteric artery invasion (37, 74%), followed by superior mesenteric vein invasion (33, 66%). Twenty-one (62%) patients underwent palliative surgery and postoperative pain relief occurred in 40 (80%) patients. The estimated blood loss in operation was 107.4 ± 115.3 mL and none of the patient received blood transfusion. The postoperative hospital stay was 7.5 ± 4.2 d; one patient had biliary fistula and three had pancreatic fistula, all of whom recovered after conservative treatment. After operation, 26 patients received chemotherapy and 24 did not. The 1-year survival rate was significantly higher in patients who received chemotherapy than in those who did not (60.7% vs 35.9%, P = 0.034). The mean overall survival of patients of the chemotherapy group and non-chemotherapy group was 14 and 11 mo, respectively (χ² = 3.970, P = 0.046).

CONCLUSION

Radioactive ¹²⁵I seed implantation combined with postoperative chemotherapy can prolong the survival time, relieve pain, and improve the quality of life of patients with locally advanced pancreatic cancer.

Comparison of transcriptional profiles in human lymphocyte cells irradiated with 12C ion beams at 0-2.0 Gy

OBJECTIVE

Heavy ions have contributed to tumor site-specific radiotherapy and are a major health risk for astronauts. The purpose of this study was to investigate the changes in gene expression in peripheral lymphocytes of cancer patients and astronauts exposed to 12C ions, and identify suitable molecular biomarkers for health monitoring. We also aimed to observe the effects of treatment and the level of damage, by comparing the transcriptional profiles of human lymphocyte cell lines exposed to 12C ion beams at doses of 0-2.0 Gy.

MATERIALS AND METHODS

A human lymphocyte cell line was irradiated with 12C ion beams at 0, 0.1, 0.5, and 2.0 Gy and transcriptional profiles were evaluated using the Agilent human gene expression microarray at 24 hours after irradiation. Differentially expressed genes were identified using a fold change of ≥2.0. Representative genes were further validated by RT-PCR. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses were performed to determine the roles of differentially expressed mRNAs.

RESULTS

Based on the microarray assays, 1,113 genes were upregulated and 853 genes were downregulated in human lymphocyte cells irradiated with 0.1 Gy 12C ion beams compared with the control group, 1,095 genes were upregulated and 1,220 genes were downregulated in cells irradiated with 0.5 Gy 12C ion beams, and 1,055 genes were upregulated and 1,356 genes were downregulated in cells irradiated with 2.0 Gy. A total of 504 genes were differentially expressed in all irradiated groups, of which 88 genes were upregulated and 416 genes downregulated. Most of these altered genes were related to the cell cycle, apoptosis, signal transduction, DNA transcription, repair, and replication. The expression differences were further confirmed by RT-PCR for a subset of differentially expressed genes.

CONCLUSION

Differentially expressed genes between treatment and control groups at 24 hours post-irradiation increased as the radiation dose increased; upregulated genes gradually decreased and downregulated genes increased. Our data indicated that 12C ion beams could repress a number of genes in a dose-dependent manner, which might lead to the failure of multiple cellular biological functions.