J. Doyen

Expression of a truncated active form of VDAC1 in lung cancer associates with hypoxic cell survival and correlates with progression to chemotherapy resistance

Resistance to chemotherapy-induced apoptosis of tumor cells represents a major hurdle to efficient cancer therapy. Although resistance is a characteristic of tumor cells that evolve in a low oxygen environment (hypoxia), the mechanisms involved remain elusive. We observed that mitochondria of certain hypoxic cells take on an enlarged appearance with reorganized cristae. In these cells, we found that a major mitochondrial protein regulating metabolism and apoptosis, the voltage-dependent anion channel 1 (VDAC1), was linked to chemoresistance when in a truncated (VDAC1-ΔC) but active form. The formation of truncated VDAC1, which had a similar channel activity and voltage dependency as full-length, was hypoxia-inducible factor-1 (HIF-1)-dependent and could be inhibited in the presence of the tetracycline antibiotics doxycycline and minocycline, known inhibitors of metalloproteases. Its formation was also reversible upon cell reoxygenation and associated with cell survival through binding to the antiapoptotic protein hexokinase. Hypoxic cells containing VDAC1-ΔC were less sensitive to staurosporine- and etoposide-induced cell death, and silencing of VDAC1-ΔC or treatment with the tetracycline antibiotics restored sensitivity. Clinically, VDAC1-ΔC was detected in tumor tissues of patients with lung adenocarcinomas and was found more frequently in large and late-stage tumors. Together, our findings show that via induction of VDAC1-ΔC, HIF-1 confers selective protection from apoptosis that allows maintenance of ATP and cell survival in hypoxia. VDAC1-ΔC may also hold promise as a biomarker for tumor progression in chemotherapy-resistant patients.

Knock-down of hypoxia-induced carbonic anhydrases IX and XII radiosensitizes tumor cells by increasing intracellular acidosis.

The relationship between acidosis within the tumor microenvironment and radioresistance of hypoxic tumor cells remains unclear. Previously we reported that hypoxia-induced carbonic anhydrases (CA) IX and CAXII constitute a robust intracellular pH (pHi)-regulating system that confers a survival advantage on hypoxic human colon carcinoma LS174Tr cells in acidic microenvironments. Here we investigate the role of acidosis, CAIX and CAXII knock-down in combination with ionizing radiation. Fibroblasts cells (-/+ CAIX) and LS174Tr cells (inducible knock-down for ca9/ca12) were analyzed for cell cycle phase distribution and survival after irradiation in extracellular pHo manipulations and hypoxia (1% O2) exposure. Radiotherapy was used to target ca9/ca12-silenced LS174Tr tumors grown in nude mice. We found that diminishing the pHi-regulating capacity of fibroblasts through inhibition of Na+/H+ exchanger 1 sensitize cells to radiation-induced cell death. Secondly, the pHi-regulating function of CAIX plays a key protective role in irradiated fibroblasts in an acidic environment as accompanied by a reduced number of cells in the radiosensitive phases of the cell cycle. Thirdly, we demonstrate that irradiation of LS174Tr spheroids, silenced for either ca9 or both ca9/ca12, showed a respective 50 and 75% increase in cell death as a result of a decrease in cell number in the radioresistant S phase and a disruption of CA-mediated pHi regulation. Finally, LS174Tr tumor progression was strongly decreased when ca9/ca12 silencing was combined with irradiation in vivo. These findings highlight the combinatory use of radiotherapy with targeting of the pHi-regulating CAs as an anti-cancer strategy.

Dose de tolérance des tissus sains: le cœur

Radistion thoracic tumors may be associated with cardiac toxicity because of the central position of the heart in the thorax. The present review aims to describe the cardiotoxicity during radiotherapy of different tumor sites most associated with this complication and the risk factors of cardiotoxicity during radiation therapy. Medline literature searches were performed using the following cardiac--heart--radiotherapy--toxicity--cardiotoxicity--breast cancer--lymphoma. Cardiac toxicity after breast cancer and mediastinal lymphoma is the most reported radiation-induced complication. The most frequent clinical complications are pericarditis, congestive heart failure, and heart infarction. These events are mostly asymptomatic. Thus clinicians have to give particular attention to these complications. Anthracyclin treatment is a major risk factor for additional cardiotoxicity during radiotherapy with a synergistic effect. Correction of cardiovascular risk is an important point of the prevention of heart complications. Total dose delivered to the planned target volume (PTV), the dose per fraction and the irradiated volume were correlated to the risk of cardiotoxicity. Volume of heart receiving 35 Gy must be inferior to 30% and dose per fraction should not exceed 2 Gy when dose of prescription exceeds 30 Gy. Maximum heart distance (maximal thickness of heart irradiated) must be less than 1cm during irradiation of breast cancer. Modern irradiation techniques seem to be associated with a limited risk of heart complication. The use of anthracycline, other cardiotoxic chemotherapies and targeted therapies should incite for great caution by performing a careful treatment planning and optimisation.

Proton beams in cancer treatments: Clinical outcomes and dosimetric comparisons with photon therapy

PURPOSE To review current evidence of the role of proton therapy (PT) in other tumors than skull base, sinusal/parasinusal, spinal and pediatric tumors; to determine medico-economic aspects raised by PT. MATERIAL AND METHODS A systematic review on Medline was performed with the following keywords: proton therapy, proton beam, protontherapy, cancer; publications with comparison between PT and photon-therapy were also selected. RESULTS In silico studies have shown superiority (better dose delivery to the target and/or to organs at risk) of PT toward photon-therapy in most of thoracic and abdominal malignant tumors. Potential benefits of PT could be: reduction of toxicities (including radiation-induced cancer), increase of tumor control through a dose-escalation approach, hypofractionation. Cost of treatment is always cited as an issue which actually can be managed by a precise patient selection making PT a cost-effective procedure. Comparison plan with photon therapy may be useful to determine the dosimetric and clinical advantages of PT (Normal Tissue Complications Probability). CONCLUSION PT may be associated with a great advantage compared to the best photon-therapies in various types of cancers. Accumulation of clinical data is on-going and will challenge the in silico data analysis. Some indications are associated with strong superiority of PT and may be discussed as a new standard within prospective observational studies.

Organ preservation in rectal adenocarcinoma (T1) T2-T3 Nx M0. Historical overview of the Lyon Sud - nice experience using contact x-ray brachytherapy and external beam radiotherapy for 120 patients.

In most institutions, standard treatment of T2-T3 rectal adenocarcinoma is radical surgery using total mesorectal excision (TME) with or without neoadjuvant treatment [radiotherapy or chemoradiotherapy (CRT)]. Abdomino-perineal excision (APE) is considered by most patients as a severe mutilation but even with low anterior resection (LAR) morbidity is not negligible [1]. Further, postoperative mortality, especially in elderly patients is of great concern [2]. To improve quality of life and individualize treatment, an increasing number of experienced colorectal surgeons are advocating organ preservation using CRT followed either by local excision (LE) [3,4] or only close surveillance after clinical complete response (cCR) usually in T2 or ‘ early T3 ’ tumors [5,6]. In Sao Paulo, Habr-Gama has since many years been the pioneer of such an approach recommending careful evaluation of the clinical tumor response [7] using a long interval after the end of CRT. In case of cCR, her strategy is to adopt a ‘ watch and wait ’ (W-W) policy [8]. In Lyon, Papillon using contact x-ray brachytherapy (CXB) alone was able in the 1970s to achieve close to 90% cCR in more than 300 T1 N0 lesions and gave his name to this technique [9]. Since the mid-1980s, CXB was combined with external beam radiation therapy (EBRT) in order to treat, mainly in inoperable patients, T2-3 tumors at higher risk of perirectal nodal extension [10,11]. Similar approaches were used in various French, British and American institutions [12 – 15]. Since the mid-1990s, CXB was progressively abandoned for four reasons: the Philips RT 50 TM Contact machine was not manufactured anymore, technological innovations drove the interest of radiation oncologists towards three-dimensional (3D) image-guided radiotherapy, they progressively lost the clinical expertise of rigid rectoscopy and LE became the primary treatment of malignant polyps or T1N0 tumors. In 2009 a new Contact machine named Papillon 50 TM , producing a similar 50 kV x-ray beam was introduced in UK and France and initiated a renaissance of this technique [16]. We report here an overview of the use of CXB during a time period of 35 years by a homogeneous team of radiation oncologists working successively in CHU Lyon Sud and Centre Antoine Lacassagne in Nice. The report will focus exclusively on the combined treatment using CXB with EBRT to achieve organ preservation in T2 to early T3 rectal adenocarcinomas.

Mise au pointDose de tolérance des tissus sains : le cœurNormal tissue tolerance to external beam radiation therapy: Cardiac structures☆

Radistion thoracic tumors may be associated with cardiac toxicity because of the central position of the heart in the thorax. The present review aims to describe the cardiotoxicity during radiotherapy of different tumor sites most associated with this complication and the risk factors of cardiotoxicity during radiation therapy. Medline literature searches were performed using the following cardiac--heart--radiotherapy--toxicity--cardiotoxicity--breast cancer--lymphoma. Cardiac toxicity after breast cancer and mediastinal lymphoma is the most reported radiation-induced complication. The most frequent clinical complications are pericarditis, congestive heart failure, and heart infarction. These events are mostly asymptomatic. Thus clinicians have to give particular attention to these complications. Anthracyclin treatment is a major risk factor for additional cardiotoxicity during radiotherapy with a synergistic effect. Correction of cardiovascular risk is an important point of the prevention of heart complications. Total dose delivered to the planned target volume (PTV), the dose per fraction and the irradiated volume were correlated to the risk of cardiotoxicity. Volume of heart receiving 35 Gy must be inferior to 30% and dose per fraction should not exceed 2 Gy when dose of prescription exceeds 30 Gy. Maximum heart distance (maximal thickness of heart irradiated) must be less than 1cm during irradiation of breast cancer. Modern irradiation techniques seem to be associated with a limited risk of heart complication. The use of anthracycline, other cardiotoxic chemotherapies and targeted therapies should incite for great caution by performing a careful treatment planning and optimisation.

Predictive factors for early and late local toxicities in anal cancer treated by radiotherapy in combination with or without chemotherapy.

BACKGROUND: The treatment of anal cancer is based on concomitant radiotherapy and chemotherapy and is associated with a nonnegligible rate of local severe toxicities that can strongly impair the quality of life. OBJECTIVE: A retrospective analysis was performed to screen the following factors as potential predictive factors for local skin and digestive toxicities, and as potential prognostic factors for cumulative colostomy incidence: sex, age, tumor size, clinical T and N stage, circumferential extension, invasion of anal margin, HIV status, type of chemotherapy, and type of radiotherapy and dose delivered. METHODS: One hundred five patients in our database treated between January 2000 and February 2010 met the eligibility criteria. RESULTS: Median follow-up was 54.1 months (range, 1–133). Early and late severe local toxicities occurred in 33 patients (31.4%) and 18 patients (17.1%). The 5-year cumulative rate of colostomy was 26.6%. Predictive factors for local severe early toxicities were as follows: clinical stage III/IV (p = 0.01), no brachytherapy boost (p = 0.003), and use of chemotherapy (p = 0.01). Only brachytherapy retained its independence in multivariate analysis (OR = 4.8 (1.4–16.3), p = 0.01). Human immunodeficiency virus positivity (p = 0.04) was the only predictive factor for late toxicities in univariate analysis; it was linked independently to the occurrence of ulcer (OR = 0.1 (0.01–0.66), p = 0.01). Tumor size ≥4 cm (p < 0.001) and occurrence of grade 2 to 3 ulcers (p < 0.001) were correlated with greater cumulative colostomy incidence. CONCLUSIONS: In this cohort, nonuse of brachytherapy was an independent predictive factor for local acute toxicity. Human immunodeficiency virus positivity was the only predictive factor for local late toxicities and strongly influenced the onset of ulcer.

Radiosensitivity of Colon and Rectal Lung Oligometastasis Treated With Stereotactic Ablative Radiotherapy

Introduction: Patients with metastatic colorectal cancer (CRC) may present with oligometastatic lung lesions for which stereotactic ablative radiotherapy (SABR) can be utilized. This study aims to report efficacy and prognostic factors associated with colorectal lung metastases treated with SABR. Material and Methods: This is a retrospective study including patients who presented with lung oligometastasis from CRC treated with SABR from September 2007 to November 2014. Results: We identified 53 oligometastatic patients with 87 lung lesions. The median prescription dose was 60 Gy in 3 fractions (median biological effective dose of 180 Gy). The median follow up was 33 months. The 1‐ and 2‐year local control, metastasis‐free survival, and overall survival were 79.8% and 78.2%, 29.2% and 16.2%, and 83.8% and 69.3%, respectively. On multivariate analysis, rectal primary site (P = .001) and > 2 metastases (P = .02) were significantly associated with a lower local control rate. Rectal lesions were associated with higher radiation dose (169.3 Gy vs. 153.3 Gy; P = .01) and higher rate of KRAS mutations (73.3% vs. 40.4%; P = .02). KRAS mutation did not predict for local control, but predicted for a 1‐year metastasis‐free survival detriment (0% vs. 37.5%; P = .04), when compared with KRAS wild‐type. On multivariate analysis, there is an overall survival detriment associated with gross tumor volume ≥ 3266 mm3 (P = .03) and > 2 metastases (P = .04). Conclusion: In CRC, oligometastatic lung lesions treated with SABR had a worse outcome in patients presenting with a rectal primary, > 2 metastases, or treated with a larger gross tumor volume. More aggressive treatment may be considered in this subset of patients to improve outcome. &NA; This study reports outcome of a homogenous cohort of oligometastatic patients treated with stereotactic body radiotherapy for lung lesions arising from colorectal cancer. This study demonstrated lower local control with rectal lesions, which may have a more aggressive biological behavior, as suggested by a different KRAS mutation profile.

Results of age-dependent anal canal cancer treatment: a single centre retrospective study.

BACKGROUND Information concerning management of anal canal cancer among the elderly is scarce and much less abundant than for younger subjects. POPULATION AND METHODS We retrospectively analysed 115 patients treated for anal epidermoid cancer between 2000 and 2010. The population was divided according to age (<70 years and ≥70 years). RESULTS Of the 115 patients, 81 (70.4%) were <70 years old and 34 were ≥70 years (29.6%). Tumour characteristics were identical between the two groups and median follow-up was 62 months. Elderly patients had a less favourable performance status (p=0.001) and fewer had received radiochemotherapy (61.8% vs 82.5%, p=0.004). Treatment-related grade 3 and 4 hematologic toxicity was observed more often among elderly subjects. The results at 5 years were less favourable for overall, disease-specific, and disease-free survival (respectively p=0.002, p=0.001, and p=0.001). For patients treated with a curative intent, at 5 years there was no difference between the two groups in terms of overall survival (p=0.2). However, there was a statistically significant difference in favour of the younger group for disease-free survival and metastasis-free survival. CONCLUSION If radiochemotherapy can be delivered to elderly subjects with a good general status, the effects appear less favourable than in younger patients.

Spatio-temporal genetic heterogeneity of CTNNB1 mutations in sporadic desmoid type fibromatosis lesions

Desmoid type fibromatosis (DT) is a rare lesion of unclear pathogenesis that most often presents a mutation of the (β-catenin) gene. The natural history and clinical evolution are highly variable between patients and to date there is no consensus on optimal therapy. We report two cases of a patient with multiple DT lesions. Molecular investigations performed in both patients on multiple tumors at different anatomical sites revealed non-identical CTNNB1 mutations. The first patient was a 39-year-old man with a history of recurrent DT. In two of the DT lesions, three different mutations were found in codons 41 and 45, respectively. The lesions showed marked inflammatory features, characterized by IgG4 positive lymphoplasmacytic infiltrates and a foreign body reaction, which increased in intensity over time. The patient was eventually treated with a COX-2 inhibitor and the remaining mass was stabilized. In the two DT lesions of the second patient, CTNNB1 mutations S45P and T41A were found. The presence of different mutations in multiple focally recurrent sporadic DT lesions indicates that they do not have a clonal relationship. Our data suggest that a CTNNB1 mutation is a necessary event probably by providing a selective growth advantage. An IgG4 host antigen response is discussed as a potential predisposing factor for one of the patients.