Orthovoltage intraoperative radiotherapy for locally advanced and recurrent colorectal cancer

Comparing Oncologic Outcomes and Toxicity for Combined Modality Therapy vs. Carbon-Ion Radiotherapy for Previously Irradiated Locally Recurrent Rectal Cancer

No standard treatment paradigm exists for previously irradiated locally recurrent rectal cancer (PILRRC). Carbon-ion radiotherapy (CIRT) may improve oncologic outcomes and reduce toxicity compared with combined modality therapy (CMT). Eighty-five patients treated at Institution A with CIRT alone (70.4 Gy/16 fx) and eighty-six at Institution B with CMT (30 Gy/15 fx chemoradiation, resection, intraoperative electron radiotherapy (IOERT)) between 2006 and 2019 were retrospectively compared. Overall survival (OS), pelvic re-recurrence (PR), distant metastasis (DM), or any disease progression (DP) were analyzed with the Kaplan-Meier model, with outcomes compared using the Cox proportional hazards model. Acute and late toxicities were compared, as was the 2-year cost. The median time to follow-up or death was 6.5 years. Median OS in the CIRT and CMT cohorts were 4.5 and 2.6 years, respectively (p ≤ 0.01). No difference was seen in the cumulative incidence of PR (p = 0.17), DM (p = 0.39), or DP (p = 0.19). Lower acute grade ≥ 2 skin and GI/GU toxicity and lower late grade ≥ 2 GU toxicities were associated with CIRT. Higher 2-year cumulative costs were associated with CMT. Oncologic outcomes were similar for patients treated with CIRT or CMT, although patient morbidity and cost were lower with CIRT, and CIRT was associated with longer OS. Prospective comparative studies are needed.

ESTRO/ACROP IORT recommendations for intraoperative radiation therapy in locally recurrent rectal cancer

Multimodal strategies have been implemented for locally recurrent rectal cancer scheduled for complete surgical resection. Irradiation and systemic therapy have been added to improve the oncological outcome, as surgery alone was associated with a poor prognosis. Intraoperative irradiation (IORT) is a component of irradiation intensification. Long-term cancer control and a higher survival rate were consistently reported in patients who had IORT as a component of their multidisciplinary treatment. The experience reported by expert IORT groups is reviewed and recommendations to guide clinical practice are explained in detail.

Low-kilovolt x-ray intraoperative radiotherapy for pT3 locally advanced colon cancer: a single-institution retrospective analysis

Background

Patients with locally advanced colon cancer (LACC) treated with surgery had a high risk of local recurrence. The outcomes can vary significantly among patients with pT3 disease. This study was undertaken to assess whether low-kilovolt (kV) x-ray intraoperative radiotherapy (IORT) can achieve promising results compared with electron beam IORT (IOERT) and whether specific subgroups of patients with pT3 colon cancer may benefit from low-kV x-ray IORT.

Methods

We retrospectively reviewed 44 patients with pT3 LACC treated with low-kV x-ray IORT. Clinicopathologic characteristics were analyzed to identify patients that could potentially benefit from low-kV x-ray IORT. The Kaplan-Meier survival analysis was used to assess overall survival (OS) and progression-free survival (PFS). Correlation analysis was used to discover the association of multiple factors to the results of treatment represented by the values of OS and PFS.

Results

The median follow-up of patients was 20.5 months (range, 6.1–38.8 months). At the time of analysis, 38 (86%) were alive and 6 (14%) had died of their disease. The 3-year Kaplan-Meier of PFS and OS for the entire cohort was 82.8% and 82.1%, respectively. At median follow-up, no in-field failure within the low-kV x-ray IORT field had occurred. Locoregional and distant failure had occurred in 2 (5%) patients each. The rate of perioperative 30-day mortality was 0%, and the morbidity rate was 11%. Five patients experienced 7 complications, including 4 early complications (30 days) and three late complications (> 30 days) leading early and late morbidity rates of 9% and 7%, respectively.

Conclusion

Patients with LACC who had undergone an additional low-kV x-ray IORT can achieve encouraging locoregional control, PFS, OS, and distant control without an increase in short-term or long-term complications. Low-kV x-ray IORT can be considered as part of management in pT3 LACC.

Transgelin is a poor prognostic factor associated with advanced colorectal cancer (CRC) stage promoting tumor growth and migration in a TGFβ-dependent manner

Colorectal cancer (CRC) is the fourth most common cancer type globally. Investigating the signaling pathways that maintain cancer cell phenotype can identify new biomarkers for targeted therapy. Aberrant transforming growth factor-β (TGFβ) signaling has been implicated in CRC progression, however, the exact mechanism by which TGFβ exerts its function is still being unraveled. Herein, we investigated TAGLN expression, prognostic value, and its regulation by TGFβ in CRC. While TAGLN was generally found to be downregulated in CRC, elevated expression of TAGLN was associated with advanced CRC stage and predicted poor overall survival (hazard ratio (HR) = 1.8, log-rank test P-value = 0.014) and disease-free survival (HR = 1.6, log-rank test P-value = 0.046), hence implicating TAGLN as poor prognostic factor in CRC. Forced expression of TAGLN was associated with enhanced CRC cell proliferation, clonogenic growth, cell migration and in vivo tumor formation in immunocompromised mice, while targeted depletion of TAGLN exhibited opposing biological effects. Global gene expression profiling of TAGLN-overexpressing or TAGLN-deficient CRC cell lines revealed deregulation of multiple cancer-related genes and signaling pathways. Transmission electron microscopy (TEM) revealed ultrastructural changes due to loss of TAGLN, including disruption of actin cytoskeleton organization and aberrant actin filament distribution. Hierarchical clustering, principle component, and ingenuity pathway analyses revealed distinct molecular profile associated with TAGLN^high CRC patients with remarkable activation of a number of mechanistic networks, including SMARCA4, TGFβ1, and P38 MAPK. The P38 MAPK was the top predicted upstream regulator network promoting cell movement through regulation of several intermediate molecules, including TGFβ1. Concordantly, functional categories associated with cellular movement and angiogenesis were also enriched in TAGLN^high CRC, supporting a model for the molecular mechanisms linking TGFβ-induced upregulation of TAGLN and CRC tumor progression and suggesting TAGLN as potential prognostic marker associated with advanced CRC pathological stage.

Antiproliferative and pro‑apoptotic effects of Cyclocarya paliurus polysaccharide and X‑ray irradiation combination on SW480 colorectal cancer cells

The anti-hyperglycemic effects of Cyclocarya paliurus polysaccharide (CPP) have attracted increasing attention; however, limited research has been conducted on the potential effects of CPP on inhibiting tumor growth. The present study aimed to investigate the functions of CPP in combination with X-ray irradiation on colorectal cancer cells and the underlying mechanisms. SW480 cells were treated with various concentrations of CPP for 24, 48 and 72 h to determine cell viability using a Cell Counting Kit-8 assay. Then, the cells were divided into four groups as follows: Control, CPP (100 µmol/l), 8 Gy and CPP + 8 Gy. The proliferation and apoptosis, and colony formation of cells were detected using flow cytometry and plate clone formation assays, respectively. Reverse transcription-quantitative PCR and western blot analyses were conducted to determine the expression of proliferation and apoptosis-associated, and PI3K/Akt signaling-associated genes. Treatment with 75 µmol/l CPP for 48 h significantly decreased cell viability compared with untreated cells. CPP in combination with 8 Gy X-ray treatment significantly promoted the induction of apoptosis, and suppressed cell proliferation and clone formation compared with the control, CPP and 8 Gy groups. The detection of mRNA and protein expression levels by reverse transcription-PCR and western blotting demonstrated that CPP in combination with 8 Gy not only significantly decreased the expression of proliferation marker protein Ki-67, p53 and Bcl-2, but also upregulated the expression of cleaved caspase-3 and Bax, compared with the control. In addition, CPP and 8 Gy combined significantly attenuated the phosphorylation of PI3K and Akt. The present study demonstrated that the combination of CPP with X-ray irradiation suppressed SW480 cell proliferation and promoted cell apoptosis compared with the control, CPP and 8 Gy groups. The underlying mechanisms may involve inhibition of PI3K/Akt signaling.

Intraoperative radiotherapy with low energy photons in recurrent colorectal cancer: a single centre retrospective study

AIM OF THE STUDY

Intraoperative radiotherapy (IORT) may improve outcome of surgical treatment of recurrent colorectal cancer (CRC). The aim of this study is to determine the feasibility, safety and long-term results of surgical treatment of recurrent CRC with orthovolt IORT.

MATERIAL AND METHODS

Fifty-nine consecutive CRC patients with local recurrence (LR), undergoing surgery, were included in the retrospective analysis of prospectively collected data. The modified Wanebo classification was used to stage LR (Tr). Twenty-five (43%) patients received IORT using INTRABEAM(®) PRS 500. The complications were classified according to the Clavien-Dindo classification.

RESULTS

There were 32 males and 27 females, with a median age of 63 years. Multi-visceral resections were performed in 37 (63%) patients. Median hospitalization time after surgery with IORT was 7 days. One (1.7%) in-hospital postoperative death was reported. Grade 3/4 postoperative complications were found in 11 (19%) patients. Intraoperative radiotherapy had no effect on the postoperative hospitalization time, morbidity and mortality. Median survival after R0 resection was 32 months. Complete resection (R0), no synchronous liver metastases (M0), and no lateral and posterior pelvic wall involvement, were significant predictors of improved survival. Stage of LR was found to be an independent prognostic factor in the multivariate analysis (p = 0.03); Cox regression model). In patients with LR stage < Tr5, a 3-year overall survival (OS) rate was 52%.

CONCLUSIONS

Combination of surgical resection and orthovolt IORT is a safe and feasible procedure that does not increase the risk of postoperative complications or prolongs the hospital stay. Despite aggressive surgery supported by IORT, the advanced stage of LR is a limiting factor of long-term survival.

Anti-miRNA-221 sensitizes human colorectal carcinoma cells to radiation by upregulating PTEN

AIM: To investigate the regulative effect of miRNA (miR)-221 on colorectal carcinoma (CRC) cell radiosensitivity and the underlying mechanisms.

METHODS: A human CRC-derived cell line was cultured conventionally and exposed to different doses of X-rays (0, 2, 4, 6 and 8 Gy). The total RNA and protein of the cells were extracted 24 h after irradiation, and the alteration of miR-221 and phosphatase and tensin homolog deleted on chromosome 10 (PTEN) gene mRNA expression was detected by real-time reverse transcriptase polymerase chain reaction (PCR). The protein alteration of PTEN in the cells was detected by Western blotting. Caco2 cells were pretreated with or without anti-PTEN-siRNA prior to the addition of pre-miR-221 or anti-miR-221 using Lipofectamine 2000. Colony formation assay and flow cytometry analysis were used to measure the surviving cell fraction and the sensitizing enhancement ratio after irradiation. Additionally, PTEN 3′-untranslated region fragment was PCR amplified and inserted into a luciferase reporter plasmid. The luciferase reporter plasmid construct was then transfected into CRC cells together with pre-miR-221 or anti-miR-221, and the luciferase activity in the transfected cells was detected.

RESULTS: The X-ray radiation dose had a significant effect on the expression of miR-221 and PTEN protein in human Caco2 cells in a dose-dependent manner. The miR-221 expression level improved gradually with the increase in irradiation dose, while the PTEN protein expression level reduced gradually. miR-221 expression was significantly reduced in the anti-miR-221 group compared with the pre-miR-221 and negative control groups (P < 0.01). Anti-miR-221 upregulated expression of PTEN protein and enhanced the radiosensitivity of Caco2 cells (P < 0.01). Moreover, the inhibitory effect was dramatically abolished by pretreatment with anti-PTEN-siRNA, suggesting that the enhancement of radiosensitivity was indeed mediated by PTEN. A significant increase of luciferase activity was detected in CRC cells that were cotransfected with the luciferase reporter plasmid construct and anti-miR-221 (P < 0.01).

CONCLUSION: Anti-miR-221 can enhance the radiosensitivity of CRC cells by upregulating PTEN.

Present status and future directions of intraoperative radiotherapy

In this Review, we summarise recent published work on the use of intraoperative radiotherapy to treat common tumour sites in the primary or recurrent setting. Techniques, radiobiology, and the physics of intraoperative radiotherapy are also explored. Disease sites discussed in this Review include head and neck cancer, breast cancer, sarcoma, gastrointestinal cancer, genitourinary cancer, gynaecological cancer, thoracic cancer, and palliative applications.

TAGLN suppresses proliferation and invasion, and induces apoptosis of colorectal carcinoma cells

In order to find the correlation between transgelin gene (TAGLN) and colorectal carcinoma occurrence, we investigated the expression of TAGLN in colorectal carcinoma tissue samples and colorectal carcinoma LoVo cells. Meanwhile, the effects of TAGLN on the characteristics of LoVo cells were also examined. The expressions of TAGLN in colorectal carcinoma tissues, adjacent normal tissues, and LoVo cells were detected by the Western blot method. The recombinant plasmid pcDNA3.1-TAGLN was established and transfected into LoVo cells with the help of Lipofectamine™ 2000. At the same time, the TAGLN siRNA was transfected into LoVo cells in another group. Forty-eight hours later, the expressions of TAGLN in all groups were assayed by Western blot, and the cell viability was analyzed by MTT (3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide) assay. The cell cycle and cell apoptosis were examined by flow cytometry, and the cell invasive ability was analyzed by Transwell invasion experiment. The effect of TALGN on the expression of matrix metalloproteinase 9 (MMP9) was detected by Western blot. Western blot analysis showed that the expressions of TALGN in colorectal carcinoma tissues and LoVo cells were significantly decreased compared with colorectal carcinoma adjacent normal tissues (p < 0.01). In the overexpression or RNAi experiments, the plasmid pcDNA3.1-TAGLN significantly enhanced TALGN expression (p < 0.01), and TAGLN siRNA significantly decreased TAGLN expression (p < 0.01) in LoVo cells 48 h after transfection. In addition, MTT assay indicated that the cell viability of LoVo cells in the pcDNA3.1-TAGLN transfection group was significantly lower than that in the untransfected control group (p < 0.05). Furthermore, the overexpression of TAGLN significantly lowered the cell proliferation index (p < 0.05) and improved cell apoptosis (p < 0.01) in LoVo cells. In Transwell invasive experiments, the cell number, which had migrated through the chamber membrane, significantly decreased in the pcDNA3.1-TAGLN transfection group (p < 0.05) and significantly increased in the TAGLN knockdown group (p < 0.05) compared to the untransfected control group. At the same time, the expression of MMP9 was notably inhibited in the pcDNA3.1-TAGLN transfection group (p < 0.01). The expressions of TAGLN were inhibited in colorectal carcinoma tissues and colorectal carcinoma LoVo cells. The study also demonstrated that TAGLN could attenuate the proliferation and invasive ability of LoVo cells and enhance LoVo cell apoptosis. Furthermore, the expression of MMP9 was also inhibited by TAGLN. All these results could bring us a new perspective for biological therapy in colorectal carcinoma.