Canagliflozin mediates tumor suppression alone and in combination with radiotherapy in non-small cell lung cancer (NSCLC) through inhibition of HIF-1α.

Non-small cell lung cancer (NSCLC) has a poor prognosis, and effective therapeutic strategies are lacking. The diabetes drug canagliflozin inhibits NSCLC cell proliferation and the mammalian target of rapamycin (mTOR) pathway, which mediates cell growth and survival, but it is unclear whether this drug can enhance response rates when combined with cytotoxic therapy. Here, we evaluated the effects of canagliflozin on human NSCLC response to cytotoxic therapy in tissue cultures and xenografts. Ribonucleic acid sequencing (RNA-seq), real-time quantitative PCR (RT-qPCR), metabolic function, small interfering ribonucleic acid (siRNA) knockdown, and protein expression assays were used in mechanistic analyses. We found that canagliflozin inhibited proliferation and clonogenic survival of NSCLC cells and augmented the efficacy of radiotherapy to mediate these effects and inhibit NSCLC xenograft growth. Canagliflozin treatment alone moderately inhibited mitochondrial oxidative phosphorylation and exhibited greater antiproliferative capacity than specific mitochondrial complex-I inhibitors. The treatment downregulated genes mediating hypoxia-inducible factor (HIF)-1α stability, metabolism and survival, activated adenosine monophosphate-activated protein kinase (AMPK) and inhibited mTOR, a critical activator of hypoxia-inducible factor-1α (HIF-1α) signaling. HIF-1α knockdown and stabilization experiments suggested that canagliflozin mediates antiproliferative effects, in part, through suppression of HIF-1α. Transcriptional regulatory network analysis pinpointed histone deacetylase 2 (HDAC2), a gene suppressed by canagliflozin, as a key mediator of canagliflozin's transcriptional reprogramming. HDAC2 knockdown eliminated HIF-1α levels and enhanced the antiproliferative effects of canagliflozin. HDAC2-regulated genes suppressed by canagliflozin are associated with poor prognosis in several clinical NSCLC datasets. In addition, we include evidence that canagliflozin also improves NSCLC response to chemotherapy. In summary, canagliflozin may be a promising therapy to develop in combination with cytotoxic therapy in NSCLC.

Low-dose non-targeted radiation effects in human esophageal adenocarcinoma cell lines.

PURPOSE: To investigate non-targeted radiation effects in esophageal adenocarcinoma cell lines (OE19 and OE33) using human keratinocyte and colorectal cancer cell reporters following γ-ray exposure. MATERIALS AND METHODS: Both clonogenic assays and ratiometric calcium endpoints were used to check for the occurrence of bystander signals in reporter cells. RESULTS: We report data suggesting that γ-irradiation increases cell killing over the expected linear quadratic (LQ) model levels in the OE19 cell line exposed to doses below 1 Gy, i.e. which may be suggestive to be a low hyper-radiosensitive (HRS) response to direct irradiation. Both EAC cell lines (OE19 and OE33) have the ability to produce bystander signals when irradiated cell conditioned medium (ICCM) is placed onto human keratinocyte reporters, but do not seem to be capable of responding to bystander signals when placed on their autologous reporters. Further work with human keratinocyte reporter models showed statistically significant intracellular calcium fluxes following exposure of the reporters to ICCM harvested from both EAC cell lines exposed to 0.5 Gy. CONCLUSION: These experiments suggest that the OE19 and OE33 cell lines produce bystander signals in human keratinocyte reporter cells. However, the radiosensitivity of the EAC cell lines used in this study cannot be enhanced by the bystander response since both cell lines could not respond to bystander signals.

Assessing patient characteristics and radiation-induced non-targeted effects in vivo for high dose-rate (HDR) brachytherapy.

PURPOSE: To test whether blood, urine, and tissue based colony-forming assays are a useful clinical detection tool for assessing fractionated treatment responses and non-targeted radiation effects in bystander cells. MATERIALS AND METHODS: To assess patients' responses to radiation treatments, blood serum, urine, and an esophagus explant-based in vivo colony-forming assay were used from oesophageal carcinoma patients. These patients underwent three fractions of high dose rate (HDR) intraluminal brachytherapy (ILBT). RESULTS: Human keratinocyte reporters exposed to blood sera taken after the third fraction of brachytherapy had a significant increase in cloning efficiency compared to baseline samples (p < 0.001). Such results may suggest an induced radioresistance response in bystander cells. The data also revealed a clear inverse dose-rate effect during late treatment fractions for the blood sera data only. Patient characteristics such as gender had no statistically significant effect (p > 0.05). Large variability was observed among the patients' tissue samples, these colony-forming assays showed no significant changes throughout fractionated brachytherapy (p > 0.05). CONCLUSION: Large inter-patient variability was found in the urine and tissue based assays, so these techniques were discontinued. However, the simple blood-based assay had much less variability. This technique may have future applications as a biological dosimeter to predict treatment outcome and assess non-targeted radiation effects.

Endotracheal brachytherapy alone: An effective palliative treatment for tracheal tumors.

BACKGROUND: Tracheal tumors are rare. They are usually unresectable and treated primarily with external beam radiation. The use of palliative endotracheal brachytherapy (ETBT) alone in treating patients with tracheal tumors has not been reported. METHODS: Using a prospective database, demographic, treatment, and outcome data of patients with tracheal tumors treated palliatively with ETBT from 2006 to 2014 were analyzed. Tumor and symptom responses were evaluated based on response evaluation criteria in solid tumors criteria. Survival, in-field disease control, symptom response, and duration of symptom responses were evaluated using descriptive analyses. RESULTS: Sixteen ETBT (median, 2) treatments were delivered to 8 patients. Median age was 63.4 years old. Common symptoms were hemoptysis, cough, and dyspnea. Tracheal lengths of 3.5-11 cm were treated with 5-7 Gy/fraction, using 1-3 fractions. The mean overall survival was 5 months and symptom-free survival was 6.8 months, respectively. After ETBT, 88% of patients experienced symptomatic improvement (hemoptysis [n = 3/3], cough [n = 6/7], and dyspnea [n = 4/4]). One patient developed Grade 1 stenosis that did not require intervention. CONCLUSIONS: This is among the largest series of tracheal tumors treated palliatively with ETBT alone. ETBT provided effective palliation with symptom improvement and minimal toxicity.

The involvement of serum serotonin levels producing radiation-induced bystander effects for an in vivo assay with fractionated high dose-rate (HDR) brachytherapy.

PURPOSE: The primary goal of this investigation was to observe whether measurable levels of bystander factor(s) can be detected in esophageal carcinoma patients' urine samples taken after undergoing high dose rate (HDR) intraluminal brachytherapy (ILBT). However, a small pilot study was developed to evaluate whether serotonin [5-Hydroxytryptamine (5-HT)] serum levels play an active role in the mechanisms of radiation-induced bystander effects (RIBE) at high doses. MATERIALS AND METHODS: In the present study, a colony-forming in vivo assay was developed and used for the detection of non-targeted effects. Samples of urine were collected from five esophageal carcinoma patients undergoing fractionated HDR-ILBT. To observe whether 5-HT modulates the bystander effect at higher doses, different batches of foetal bovine serum (FBS) and 5-HT were tested on the same urine samples before and after brachytherapy. RESULTS: Some of our data suggests statistically significant evidence for serotonin playing an active role as a signalling molecule at higher doses when patients underwent HDR-ILBT. CONCLUSION: However, a more thorough investigation, with a larger sample size, is warranted before serotonin can be known to play a role in bystander effects at this particular dose range and treatment regime.

Adding external beam to intra-luminal brachytherapy improves palliation in obstructive squamous cell oesophageal cancer: a prospective multi-centre randomized trial of the International Atomic Energy Agency.

BACKGROUND: Whether the combination of high dose-rate brachytherapy (HDRBT) and External Beam Radiation Therapy (EBRT) is superior to HDRBT alone for the palliation of oesophageal cancer has only been explored in a previous IAEA pilot randomized trial. METHODS: Two hundred and nineteen patients were randomized to adding EBRT or not, after receiving two fractions of HDRBT within 1 week. Each HDRBT consisted of 8 Gy prescribed at 1cm from source centre. Patients randomized to EBRT received 30 Gy in 10 fractions. The primary outcome was dysphagia-relief experience (DRE). Additional outcomes included various scores, performance status, weight and adverse events. A majority of charts, imaging and radiotherapy plans were externally audited. RESULTS: Median follow-up was 197 days, with a median OS of 188 days and an 18% survival rate at 1 year. DRE was significantly improved with combined therapy, for an absolute benefit of +18% at 200 days from randomization (p=0.019). In longitudinal regression analyses, scores for dysphagia (p=0.00005), odynophagia (p=0.006), regurgitation (p=0.00005), chest pain (p=0.0038) and performance status (p=0.0015) were all significantly improved. In contrast, weight, toxicities and overall survival were not different between study arms. CONCLUSION: Symptom improvement occurs with the addition of EBRT to standard HDRBT. The combination is well tolerated and relatively safe.

Radiotherapy plus cetuximab for locoregionally advanced head and neck cancer: 5-year survival data from a phase 3 randomised trial, and relation between cetuximab-induced rash and survival.

BACKGROUND: Previous results from our phase 3 randomised trial showed that adding cetuximab to primary radiotherapy increased overall survival in patients with locoregionally advanced squamous-cell carcinoma of the head and neck (LASCCHN) at 3 years. Here we report the 5-year survival data, and investigate the relation between cetuximab-induced rash and survival. METHODS: Patients with LASCCHN of the oropharynx, hypopharynx, or larynx with measurable disease were randomly allocated in a 1:1 ratio to receive either comprehensive head and neck radiotherapy alone for 6-7 weeks or radiotherapy plus weekly doses of cetuximab: 400 mg/m(2) initial dose, followed by seven weekly doses at 250 mg/m(2). Randomisation was done with an adaptive minimisation technique to balance assignments across stratification factors of Karnofsky performance score, T stage, N stage, and radiation fractionation. The trial was un-blinded. The primary endpoint was locoregional control, with a secondary endpoint of survival. Following discussions with the US Food and Drug Administration, the dataset was locked, except for queries to the sites about overall survival, before our previous report in 2006, so that an independent review could be done. Analyses were done on an intention-to-treat basis. Following completion of treatment, patients underwent physical examination and radiographic imaging every 4 months for 2 years, and then every 6 months thereafter. The trial is registered at www.ClinicalTrials.gov, number NCT00004227. FINDINGS: Patients were randomly assigned to receive radiotherapy with (n=211) or without (n=213) cetuximab, and all patients were followed for survival. Updated median overall survival for patients treated with cetuximab and radiotherapy was 49.0 months (95% CI 32.8-69.5) versus 29.3 months (20.6-41.4) in the radiotherapy-alone group (hazard ratio [HR] 0.73, 95% CI 0.56-0.95; p=0.018). 5-year overall survival was 45.6% in the cetuximab-plus-radiotherapy group and 36.4% in the radiotherapy-alone group. Additionally, for the patients treated with cetuximab, overall survival was significantly improved in those who experienced an acneiform rash of at least grade 2 severity compared with patients with no rash or grade 1 rash (HR 0.49, 0.34-0.72; p=0.002). INTERPRETATION: For patients with LASCCHN, cetuximab plus radiotherapy significantly improves overall survival at 5 years compared with radiotherapy alone, confirming cetuximab plus radiotherapy as an important treatment option in this group of patients. Cetuximab-treated patients with prominent cetuximab-induced rash (grade 2 or above) have better survival than patients with no or grade 1 rash. FUNDING: ImClone Systems, Merck KGaA, and Bristol-Myers Squibb.

Motexafin gadolinium combined with prompt whole brain radiotherapy prolongs time to neurologic progression in non-small-cell lung cancer patients with brain metastases: results of a phase III trial.

PURPOSE: To determine the efficacy of motexafin gadolinium (MGd) in combination with whole brain radiotherapy (WBRT) for the treatment of brain metastases from non-small-cell lung cancer. METHODS AND MATERIALS: In an international, randomized, Phase III study, patients with brain metastases from non-small-cell lung cancer were randomized to WBRT with or without MGd. The primary endpoint was the interval to neurologic progression, determined by a centralized Events Review Committee who was unaware of the treatment the patients had received. RESULTS: Of 554 patients, 275 were randomized to WBRT and 279 to WBRT+MGd. Treatment with MGd was well tolerated, and 92% of the intended doses were administered. The most common MGd-related Grade 3+ adverse events included liver function abnormalities (5.5%), asthenia (4.0%), and hypertension (4%). MGd improved the interval to neurologic progression compared with WBRT alone (15 vs. 10 months; p = 0.12, hazard ratio [HR] = 0.78) and the interval to neurocognitive progression (p = 0.057, HR = 0.78). The WBRT patients required more salvage brain surgery or radiosurgery than did the WBRT+MGd patients (54 vs. 25 salvage procedures, p < 0.001). A statistically significant interaction between the geographic region and MGd treatment effect (which was in the prespecified analysis plan) and between treatment delay and MGd treatment effect was found. In North American patients, where treatment was more prompt, a statistically significant prolongation of the interval to neurologic progression, from 8.8 months for WBRT to 24.2 months for WBRT+MGd (p = 0.004, HR = 0.53), and the interval to neurocognitive progression (p = 0.06, HR = 0.73) were observed. CONCLUSION: In the intent-to-treat analysis, MGd exhibited a favorable trend in neurologic outcomes. MGd significantly prolonged the interval to neurologic progression in non-small-cell lung cancer patients with brain metastases receiving prompt WBRT. The toxicity was acceptable.

Preliminary report on the effect of brachytherapy on expression of p53, bc1-2 and apoptosis in squamous cell carcinoma of the oesophagus.

Pre-brachytherapy biopsies and post-brachytherapy oesophagectomy specimens of 10 patients with early squamous cell carcinoma of the middle third of the oesophagus were examined for the expression of p53, bcl-2 and apoptosis using immunohistochemical markers. There was no expression of p53 in one patient in both pre- and post-brachytherapy specimens. In 8 patients, p53 staining was strongly positive (3+) with approximately 50% or more cells, and with diffuse and no specific pattern in the pre-brachytherapy biopsies. The tumour areas of the post-brachytherapy specimens of this group showed strong 3+ positivity with p53 (10-50% positive cell count), with the pattern being focal and peripheral in the tumour islands. The centre of the tumour islands showed necrosis and/or keratinisation. In one patient, the pre-brachytherapy biopsy showed expression of p53 while the post-brachytherapy specimen was negative. bcl-2 expression in both pre- and post-brachytherapy was equivocal and inconclusive in both the pre- and post-brachytherapy specimens. Apoptosis was negative in all the pre- and post-brachytherapy tissue sections in the presence of positive controls. Brachytherapy does not cause cell death by apoptosis but by necrosis and maturation of the cells into better differentiated cells, which is caused by OH free radical, and induction of the keratin gene respectively. It is possible that brachytherapy may cause destruction of cells containing wild-type p53, while mutant p53 in cells located at the tumour periphery escape the effect of brachytherapy. This may be responsible for the high incidence of local recurrence and distant metastasis in oesophageal cancer treated with radiotherapy. There is no effect of brachytherapy on bcl-2 expression in oesophageal cancer.

Prospective randomized trial of HDR brachytherapy as a sole modality in palliation of advanced esophageal carcinoma--an International Atomic Energy Agency study.

BACKGROUND: Previous studies from South Africa have established that fractionated high-dose-rate (HDR) brachytherapy gives the best results in terms of palliation and survival in advanced esophageal cancer. A multicenter, prospective randomized study was therefore conducted under the auspices of the International Atomic Energy Agency to evaluate two HDR regimens. METHODS AND MATERIALS: Surgically inoperable patients with histologically proven squamous cell cancer of the esophagus, tumor >5 cm in length on barium swallow and/or endoscopy, Karnofsky performance score >50, age 17-70 years, primary disease in the thoracic esophagus, no prior malignancy within the past 5 years, and any N or M status were included in the study. Exclusion criteria included cervical esophagus location, tumor extending <1 cm from the gastroesophageal junction, tracheoesophageal fistula, Karnofsky performance score <50, altered mental status, and extension to great vessels on CT. Patients were randomized to receive 18 Gy in 3 fractions on alternate days (6 Gy per fraction, Group A) or 16 Gy in 2 fractions on alternate days (8 Gy per fraction, Group B). The HDR dose was prescribed at 1 cm from the center of the source axis after dose optimization. A margin of 2 cm was included proximally and distally. The respective hospital and university committees gave approval for the study, and all patients provided informed consent. RESULTS: A total of 232 patients were entered into the study (112 in Group A and 120 in Group B). There was no difference between the groups for any of the prognostic variables. All patients were followed until death. The dysphagia-free survival for the whole group was 7.1 months (Group A, 7.8 months; Group B, 6.3 months; p >0.05). The overall survival was 7.9 months for the whole group (Group A, 9.1 months; Group B, 6.9 months; p >0.05). On univariate analysis, the presenting weight (p = 0.0083), gender (p = 0.0038), race (p = 0.0105), the presenting dysphagia score (p = 0.0083), the treatment center (p = 0.0029), and tumor grade (p = 0.0029) had an impact on the dysphagia-free survival, and gender (p = 0.0011) and performance score (p = 0.0060) had an impact on dysphagia-free survival on multivariate analysis. Only age had an impact on overall survival on both univariate (p = 0.0430) and multivariate (p = 0.0331) analysis. The incidence of strictures (Group A, n = 12; Group B, n = 13; p >0.05) and fistulas (Group A, n = 11; Group B, n = 12; p >0.05) was similar in both groups. CONCLUSION: Fractionated HDR brachytherapy alone is an effective method of palliating advanced esophageal cancers, surpassing the results of any other modality of treatment presently available. Dose fractions of 6 Gy x 3 and 8 Gy x 2 give similar results for dysphagia-free survival, overall survival, strictures, and fistulas and are equally effective in palliation of advanced esophageal cancer.