Germline TP53 mutations in BRCA1 and BRCA2 mutation-negative French Canadian breast cancer families

About 40% of French Canadian breast and/or ovarian cancer families harbor germline BRCA1 or BRCA1 mutations where common mutations account for about 84% of all mutations identified in cancer families. Within a series of BRCA1 and BRCA2 mutation-negative families, a germline TP53 13398 G>A (Arg213Gln) mutation was identified, which was selected for mutation analysis in this gene because of a family history consistent with Li–Fraumeni syndrome (LFS). Given the founder effects in this population, the 13398 G>A mutation was screened in series of 52 BRCA1 and BRCA2 mutation-negative cancer families, and a mutation-positive family was identified. However, pedigree inspection and expansion of mutation-positive families with the same mutation revealed that they were closely related to each other. To further characterize the contribution of TP53 in cancer families, mutation analysis was performed in the remaining BRCA1 and BRCA2 mutation-negative cancer families. Thirty sequence variants were identified, the majority of which occur in intronic sequences and are not predicted to affect the functionality of TP53. However, the 14538 G>A (Arg290His) mutation was identified in a family which did not exhibit features consistent with LFS or Li–Fraumeni-like (LFL) syndrome. Neither of the TP53 mutations was detected in 381 French Canadian women with breast cancer diagnosed before 50 years of age not selected for family history of cancer. In all, germline TP53 mutations were identified in two of 52 (3.8%) cancer families, suggesting that TP53 is not a major contributor to BRCA1 and BRCA2 mutation-negative breast and/or ovarian cancer families of French Canadian descent.     

Rationale for targeted therapies in hepatocellular carcinoma

Recent results showing survival improvement with sorafenib, a multitargeted kinase inhibitor, in patients with advanced hepatocellular carcinoma (HCC) suggest the important role of vascular endothelial growth factor receptor (VEGFR)/platelet-derived growth factor receptor (PDGFR)/Ras signaling in this disease. In preclinical studies, hypoxia, along with vascular endothelial growth factor (VEGF) and VEGFR strongly promote angiogenesis in multiple models including HCC. VEGF and VEGFR, other tyrosine kinase receptors such as the insulin growth factor receptor type 1 (IGF-1R), and the epidermal growth factor receptor (EGFR)-1, along with intracytoplasmic kinases such as the mammalian target of rapamycin (mTOR) have been tested in preclinical studies and/or clinical trials and validated as potential targets for therapeutic interventions in HCC. In this review, we will update preclinical data supporting the rationale for clinical development and potential combinations using novel targeted therapies in patients with HCC.     

Expression of mdr1 gene in human breast primary tumors and metastases

Summary Expression of mdr1 gene has been evaluated in 34 tumor samples obtained from breast cancer patients who were classified according to their treatment, and clinical follow-up. No gene amplification was found. mdr1-RNA was never detected in 29 primary breast tumors including 5 samples from patients previously treated by 6 courses of 5-fluorouracil, epirubicin, cyclophosphamide (FEC). On the other hand, mdr1-RNA expression was detected in 1 local recurrence and 2 out of 3 metastases, all of them being treated and exhibiting a poor evolution. A second, untreated local recurrence remained negative. Clinical follow-up for 7 to 48 months in patients receiving chemotherapy showed that absence of mdr1-RNA could not be an accurate factor of satisfactory response to chemotherapy. But, all the patients with detectable mdr1-RNA exhibited a poor evolution and response to treatment. In conclusion, evaluation of mdr1-RNA seemed to be of little interest in primary breast tumors. However, the concomitant presence of an mdr1-RNA and a metastatic phenotype could give a new insight into the relationship between invasive and resistance properties of cancer cells. Such situations would need to be analyzed very carefully for a better utilization of chemotherapy.     

Telomere-driven genomic instability in cancer cells

Telomeres, the ends of linear chromosomes, play a major role in the maintenance of genome integrity. Telomerase or alternative lengthening of telomeres (ALT) mechanisms exist in most cancer cells in order to stabilize telomere length by the addition of telomeric repeats. Telomere loss can be dramatically mutagenic. Chromosomes lacking one telomere remain unstable until they are capped, generating chromosomal instability, gene amplification via breakage/fusion/bridge (B/F/B) cycles and resulting in chromosome imbalances. The chronology of the occurrence of gene amplification and chromosome imbalances detected in human tumors is still unknown. All of the aberrations that occur prior to, during or after activation of a telomere maintenance mechanism promote the development of cancer.     

1,25-dihydroxycholecalciferol: endocrinology meets the immune system

Previous work has demonstrated that, besides its effects on Ca and bone metabolism, the active form of cholecalciferol, 1,25-dihydroxycholecalciferol (1,25(OH)2D3), possesses pronounced immunomodulatory effects. In non-obese diabetic (NOD) mice primary (before disease onset), secondary (after insulitis but before diabetes onset) as well as tertiary (after transplantation of syngeneic islets) prevention of diabetes was demonstrated with 1,25(OH)2D3 and its chemically-manufactured non-hypercalcaemic analogues. 1,25(OH)2D3 exerts its immune effects both at the level of the T lymphocyte (shift in cytokine profile from T-helper (Th)1 to Th2, enhanced sensitivity to apoptosis-inducing signals) as well as at the level of the antigen-presenting cell (reduced antigen presentation, reduced production of Th1-promoting cytokines, reduced expression of co-stimulatory molecules). Also, physiologically, 1,25(OH)2D3 is believed to have a role in the immune system by serving as a negative feedback signal, limiting the mounted immune reaction. To test the clinical applicability of 1,25(OH)2D3 as treatment for type 1 diabetes in genetically-at-risk young children, we tested whether short-term early-life intervention with cholecalciferol or non-hypercalcaemic analogues of 1,25(OH)2D3 could prevent diabetes in NOD mice. Significant protection of pancreatic beta cells against autoimmune destruction was observed in analogue-treated and especially in cholecalciferol-treated NOD mice as compared with controls (P<0.005). This short-term early-life intervention was, however, not able to protect the mice from developing diabetes during their lifetime. Possible solutions are longer or combined treatments with other immunomodulators that have synergistic effects with 1,25(OH)2D3 and its analogues.     

Fibromyalgia syndrome: an overview of potential drug targets

Fibromyalgia syndrome (FMS) is a chronic disease of widespread and debilitating pain. The cause of FMS is unknown and its risk factors are poorly understood. It occurs frequently in the general population where it is often co-morbid with other rheumatoid and pain disorders, and psychiatric disorders such as anxiety and depression, making diagnosis particularly difficult. Several types of drugs are used to treat FMS, but none are specifically approved for this indication. FMS appears to be strongly associated with depression or at least with some symptoms of depression, and antidepressants appear to be effective in the treatment of this disorder. The advent of new classes of antidepressants with fewer side effects than older drugs has suggested new avenues of therapy for patients diagnosed with FMS.     

Tricyclic series of heat shock protein 90 (Hsp90) inhibitors part I: discovery of tricyclic imidazo[4,5-c]pyridines as potent inhibitors of the Hsp90 molecular chaperone

A novel class of heat shock protein 90 (Hsp90) inhibitors was developed after a low throughput screen (LTS) of a focused library containing approximately 21K compounds selected by virtual screening. The initial [1-{3-H-imidazo[4-5-c]pyridin-2-yl}-3,4-dihydro-2H-pyrido[2,1-a]isoindole-6-one] (1) compound showed moderate activity (IC(50) = 7.6 μM on Hsp82, the yeast homologue of Hsp90). A high-resolution X-ray structure shows that compound 1 binds into an "induced" hydrophobic pocket, 10-15 ? away from the ATP/resorcinol binding site. Iterative cycles of structure-based drug design (SBDD) and chemical synthesis led to the design and preparation of analogues with improved affinity. These optimized molecules make productive interactions within the ATP binding site as reported by other Hsp90 inhibitors. This resulted in compound 8, which is a highly potent inhibitor in biochemical and cellular assays (K(d) = 0.35 nM on Hsp90; IC(50) = 30 nM on SKBr3 mammary carcinoma cells) and in an in vivo leukemia model.     

NY-ESO-1/LAGE-1 coexpression with MAGE-A cancer/testis antigens: a tissue microarray study

The characterization of the expression pattern of different families of cancer/testis (C/T) antigens in different tumors, at the protein level, might be of relevance in the development of multiantigen vaccine preparations for active specific immunotherapy. We have used tissue microarray (TMA) technology to explore in large numbers of tumor specimens the expression of NY-ESO-1/LAGE-1 C/T antigens and its correlation with MAGE-A expression by using D8.38 and 57B monoclonal antibodies (MAb). The epitopes recognized by these reagents in C/T antigens were identified by molecular mapping by using a bacterial expression system. Out of 2,052 samples, 119 (5.8%) scored positive upon staining with D8.38 NY-ESO-1/LAGE-1-specific MAb. Expression in >10% of cases was detectable in melanoma and basalioma (31.6 and 18.2%, respectively), large cell carcinomas and adenocarcinomas of the lung (17.8 and 10.5%, respectively), stomach adenocarcinomas of the intestinal type (13.2%), pT2-4 bladder TCC (18.2%), nonseminomatous carcinomas of the testis (10.4%) and liposarcomas (15.4%). Simultaneous expression of NY-ESO-1/LAGE-1 and MAGE-A C/T antigens was then addressed in a TMA where 101/845 and 73/845 samples (12 and 8.6%, respectively) showed evidence of MAGE-A or NY-ESO-1/LAGE-1 specific staining, respectively. In 35/845 specimens (4.1%) concomitant expression of MAGE-A and NY-ESO-1/LAGE-1 was observed (p = 0.0002). Discrepancies in the expression of NY-ESO-1/LAGE-1 and MAGE-A were conspicuously detectable in squamous cell carcinomas of the skin (MAGE-A positive but NY-ESO-1/LAGE-1 negative) and in liposarcomas (NY-ESO-1/LAGE-1 positive, but MAGE-A negative). Taken together, these data suggest novel areas of application of C/T antigens targeted active specific immunotherapy possibly based on multiantigen vaccine preparations.     

Urine testing to monitor the impact of HPV vaccination in Bhutan and Rwanda

Bhutan (2010) and Rwanda (2011) were the first countries in Asia and Africa to introduce national, primarily school‐based, human papillomavirus (HPV) vaccination programmes. These target 12 year‐old girls and initially included catch‐up campaigns (13–18 year‐olds in Bhutan and ninth school grade in Rwanda). In 2013, to obtain the earliest indicators of vaccine effectiveness, we performed two school‐based HPV urine surveys; 973 female students (median age: 19 years, 5th‐95th percentile: 18–22) were recruited in Bhutan and 912 (19 years, 17–20) in Rwanda. Participants self‐collected a first‐void urine sample using a validated protocol. HPV prevalence was obtained using two PCR assays that differ in sensitivity and type spectrum, namely GP5+/GP6+ and E7‐MPG. 92% students in Bhutan and 43% in Rwanda reported to have been vaccinated (median vaccination age = 16, 5th–95th: 14–18). HPV positivity in urine was significantly associated with sexual activity measures. In Rwanda, HPV6/11/16/18 prevalence was lower in vaccinated than in unvaccinated students (prevalence ratio, PR = 0.12, 95% confidence interval, CI: 0.03–0.51 by GP5+/GP6+, and 0.45, CI: 0.23–0.90 by E7‐MPG). For E7‐MPG, cross‐protection against 10 high‐risk types phylogenetically related to HPV16 or 18 was of borderline significance (PR = 0.68; 95% CI: 0.45–1.01). In Bhutan, HPV6/11/16/18 prevalence by GP5+/GP6+ was lower in vaccinated than in unvaccinated students but CIs were broad. In conclusion, our study supports the feasibility of urine surveys to monitor HPV vaccination and quantifies the effectiveness of the quadrivalent vaccine in women vaccinated after pre‐adolescence. Future similar surveys should detect increases in vaccine effectiveness if vaccination of 12 year‐olds continues.     

Protoflavonoids from ferns impair centrosomal integrity of tumor cells

Six protoflavonoids, including two new compounds, were isolated during a large scale screening of fern extracts for original interaction with mitosis. The new compounds isolated from PHEGOPTERIS decursive-pinnata and EQUISETUM fluviatile were 2',3'-dihydroprotogenkwanone (1) and 2',3'-dihydro-2'-hydroxyprotoapigenone (2). Known compounds were: protoapigenone, protogenkwanone, protoapigenin, and 4'- O- β-D-glucopyranosyl protoapigenin. They showed a cytotoxic activity against HeLa cells at a micromolar level. IC?? values were 2 μM for compound 1 > 10 μM for compound 2, and respectively 2.4, 0.6, > 10 μM for the known compounds. Their cytotoxic effects were associated with phenotypic changes never observed before and characterized by the loss of centrosomal γ-tubulin labelling in both mitotic and interphasic cells.