Exploring the radiosensitizing potential of AZD8931: a pilot study on the human LoVo colorectal cancer cell line.

AIM: To explore the radiosensitizing effect of AZD8931, a novel equipotent and reversible inhibitor of signaling by EGFR (HER1), HER2 and HER3 receptors, focusing on cell cycle progression, apoptosis and clonogenic capacity in the human LoVo colorectal cancer (CRC) cell line, also in comparison with the EGFR-blocking monoclonal antibody Cetuximab or the EGFR tyrosine kinase selective small molecular inhibitor Gefitinib. MATERIALS AND METHODS: Cells were pretreated with EGFR inhibitors for 5 consecutive days and then exposed or not to ionizing radiation (IR) (2 Gy daily for 3 consecutive days). Cell proliferation, cell cycle progression and apoptosis were evaluated by flow cytometry and enzyme-linked immunosorbent assay (ELISA), clonogenic potential and radiosensitivity were studied by colony formation assay. RESULTS: AZD8931 induced cell cycle arrest and apoptosis more effectively than Gefitinib and Cetuximab and, more importantly, it was significantly more potent than Gefitinib and Cetuximab in radiosensitizing cells. This radiosensitizing action by AZD8931 mainly occurred by markedly reducing cell cycle progression into S phase, the most radioresistant phase of cell cycle, secondly by inducing apoptosis and reducing clonogenic survival. CONCLUSIONS: Our results show that AZD8931 increases IR efficacy in LoVo cells, suggesting that it works as a potent radiosensitizer, even more efficient than Gefitinib and Cetuximab, opening new pathways of investigation for further in vitro and in vivo studies aimed at confirming its potential to improve local radiotherapy in CRC.

Pervasive mutations of JAK-STAT pathway genes in classical Hodgkin lymphoma.

Dissecting the pathogenesis of classical Hodgkin lymphoma (cHL), a common cancer in young adults, remains challenging because of the rarity of tumor cells in involved tissues (usually <5%). Here, we analyzed the coding genome of cHL by microdissecting tumor and normal cells from 34 patient biopsies for a total of ∼50 000 singly isolated lymphoma cells. We uncovered several recurrently mutated genes, namely, STAT6 (32% of cases), GNA13 (24%), XPO1 (18%), and ITPKB (16%), and document the functional role of mutant STAT6 in sustaining tumor cell viability. Mutations of STAT6 genetically and functionally cooperated with disruption of SOCS1, a JAK-STAT pathway inhibitor, to promote cHL growth. Overall, 87% of cases showed dysregulation of the JAK-STAT pathway by genetic alterations in multiple genes (also including STAT3, STAT5B, JAK1, JAK2, and PTPN1), attesting to the pivotal role of this pathway in cHL pathogenesis and highlighting its potential as a new therapeutic target in this disease.

Influence of chemotherapeutic drug-related gene polymorphisms on toxicity and survival of early breast cancer patients receiving adjuvant chemotherapy.

BACKGROUND: We investigated whether GSTT1 ("null" allele), GSTM1 ("null"allele), GSTP1 (A313G), RFC1 (G80A), MTHFR (C677T), TS (2R/3R) polymorphisms were associated with toxicity and survival in patients with early breast cancer (EBC) treated with adjuvant chemotherapy (CT). METHODS: This prospective trial included patients with stage I-III BC subjected to CT with CMF or FEC regimens. PCR-RFLP was performed for MTHFR, RFC1 and GSTP1, while PCR for TS, GSTT1 and GSTM1 genes. RESULTS: Among the 244 patients consecutively enrolled, 48.7% were treated with FEC and 51.3% with CMF. Patients with TS2R/3R genotype showed less frequently severe neutropenia (G3/G4) than those with TS2R/2R and 3R/3R genotype (p = 0.038). Patients with MTHFRCT genotype had a higher probability of developing severe neutropenia than those with MTHFR CC genotype (p = 0.043). Patients with RFC1GG or GSTT1-null genotype or their combination (GSTT1-null/RFC1GG) were significantly associated with a shorter disease free survival (DFS) (p = 0.009, p = 0.053, p = 0.003, respectively) and overall survival (OS) (p = 0.036, p = 0.015, p = 0.005, respectively). Multivariate analysis confirmed the association of RFC1GG genotype with a shorter DFS (p = 0.018) and of GSTT1-null genotype of a worse OS (p = 0.003), as well as for the combined genotypes GSTT1-null/RFC1GG, (DFS: p = 0.004 and OS: p = 0.003). CONCLUSIONS: Our data suggest that TS2R/2R and 3R/3R or MTHFR CT genotypes have a potential role in identifying patients with greater risk of toxicity to CMF/FEC and that RFC1 GG and GSTT1-null genotypes alone or in combination could be important markers in predicting clinical outcome in EBC patients.

Gefitinib enhances the effects of combined radiotherapy and 5-fluorouracil in a colorectal cancer cell line.

PURPOSE: In a phase I/II trial, patients with locally advanced rectal cancer received preoperative radiotherapy (RT) and concurrent with 5-fluorouracil (5-FU) and gefitinib. Results were promising. To elucidate the molecular and biological effects, we replicated the schedule in the LoVo human colorectal adenocarcinoma cell line. METHODS: RT (2 Gy daily for 3 days), 5-FU (0.3, 0.6, 1.25, 2.5, 5, 10 µM) and gefitinib (0.2, 0.4, 0.8 µM) were administered alone, in double combinations and all together. We assessed viable cells, cell cycle, cyclin, p53 and p21 expression, signalling pathways by means of phosphorylated epidermal growth factor receptor (p-EGFR), p-AKT and p-ERK 1-2 and clonogenic capacity. RESULTS: RT and 5-FU were cytotoxic. Gefitinib was cytostatic. RT reduced clonogenic capacity more than 5-FU. 5-FU induced more cell death than RT, but surviving cells were proliferative (cyclins and p-EGFR increased). 5-FU + RT had a synergistic effect. Gefitinib, enhancing G1 accumulation, reduced proliferation of cells surviving 5-FU and 5-FU + RT. It slightly increased the cytotoxicity of RT and 5-FU. CONCLUSIONS: As gefitinib limited the proliferation rate of cells surviving 5-FU and 5-FU + RT in the LoVo cell line, it may be a useful addition to chemotherapy and RT in rectal cancer patients.

Plasma DNA, microsatellite alterations, and p53 tumor mutations are associated with disease-free survival in radically resected non-small cell lung cancer patients: a study of the perugia multidisciplinary team for thoracic oncology.

INTRODUCTION: This prospective study examined association between circulating plasma DNA, microsatellite alterations (MA), p53 mutations with time to relapse and survival in surgically treated non-small cell lung cancer (NSCLC) patients (pts). METHODS: Plasma samples, adjacent lung tissue, and lung tumor tissue specimens were collected from consecutive patients with stage I-III NSCLC. Blood samples of 66 matched healthy donors with positive smoking history were collected as controls. The plasma DNA amount was determined by real-time PCR. The analysis of MA at loci D3S1300, D3S1289, D3S1266, and D3S2338 on chromosome 3p was performed by radiolabeled PCR. p53 Mutations (exons 5, 6, 7, and 8) were detected by PCR-single-strand conformational polymorphism assay. RESULTS: There were 76 patients, 65 men; median age was 68 years (range, 42-86), 20 had stage I, 40 stage II, and 16 stage III, the majority of pts (48.7%) had squamous-cell histology. Sixty-nine (91%) were smokers and most had good Eastern Cooperative Oncology Group performance status (0/1:72/4). Mean circulating DNA of all pts was 60 ng/ml versus 5 ng/ml in smoker-matched controls (p < 0.0001). In pts without recurrence, mean circulating DNA was 48.5 ng/ml at baseline, 32.8 ng/ml at 3 month, and 20.6 ng/ml at 12 month after surgery. In pts with recurrence, mean circulating DNA at baseline was 97.1 ng/ml. At 3 month after surgery, mean DNA concentration was significantly lower in disease-free pts than in patients with recurrent disease (32.8 versus 292.7 ng/ml; p = 0.0016). MA in at least one locus was found in 39.5% of NSCLC tumors. p53 Genomic mutations were observed in 54.0% of tumor samples. Statistically significant associations were observed between MA and squamous-cell histotype (p = 0.007) and between p53 mutations and lymph node involvement (p = 0.012). MA and p53 mutations were found to be significantly associated with recurrence of disease (p = 0.033 and 0.026, respectively). CONCLUSION: Our results suggest that MA and p53 mutations in tumor DNA have a potential prognostic role for disease recurrence in NSCLC patients, and elevated levels of plasma circulating DNA identify patients with possible systemic disease at diagnosis. This might be proposed as an early detection test of disease recurrence.