SUMMARY Centrosome amplification is a common feature of human tumors, but whether this is a cause or a consequence of cancer remains unclear. Here, we test the consequence of centrosome amplification by creating mice in which centrosome number can be chronically increased in the absence of additional genetic defects. We show that increasing centrosome number elevated tumor initiation in a mouse model of intestinal neoplasia. Most importantly, we demonstrate that supernumerary centrosomes are sufficient to drive aneuploidy and the development of spontaneous tumors in multiple tissues. Tumors arising from centrosome amplification exhibit frequent mitotic errors and possess complex karyotypes, recapitulating a common feature of human cancer. Together, our data support a direct causal relationship between centrosome amplification, genomic instability and tumor development.

Haploinsufficiency of ribosomal proteins (RPs) has been proposed to be the common basis for the anemia observed in Diamond-Blackfan anemia (DBA) and myelodysplastic syndrome with loss of chromosome 5q [del(5q) MDS]. We have modeled DBA and del(5q) MDS in zebrafish using antisense morpholinos to rps19 and rps14, respectively, and have demonstrated that, as in humans, haploinsufficient levels of these proteins lead to a profound anemia. To address the hypothesis that RP loss results in impaired mRNA translation, we treated Rps19 and Rps14-deficient embryos with the amino acid L-leucine, a known activator of mRNA translation. This resulted in a striking improvement of the anemia associated with RP loss. We confirmed our findings in primary human CD34 ؉ cells, after shRNA knockdown of RPS19 and RPS14. Furthermore, we showed that loss of Rps19 or Rps14 activates the mTOR pathway, and this is accentuated by L-leucine in both Rps19 and Rps14 morphants. This effect could be abrogated by rapamycin suggesting that mTOR signaling may be responsible for the improvement in anemia associated with L-leucine. Our studies support the rationale for ongoing clinical trials of L-leucine as a therapeutic agent for DBA, and potentially for patients with del(5q) MDS. (Blood. 2012; 120(11):2214-2224) IntroductionDiamond-Blackfan anemia (DBA; MIM# 105650) is a congenital bone marrow failure syndrome of childhood manifested as normochromic macrocytic anemia with absence or insufficient erythroid precursors in the bone marrow. 1,2 Twenty-five percent of DBA patients have mutations in the RPS19 gene, which encodes a component of the 40S ribosomal subunit. 3,4 A further 25% of DBA patients have been shown to have mutations in other ribosomal protein genes, 5 supporting the hypothesis that DBA is a disease of altered ribosome assembly or function. DBA shares a number of its clinical features with several other congenital syndromes that also carry heterozygous mutations affecting ribosome biogenesis, such as Shwachman-Diamond syndrome (SDS), cartilage-hair hypoplasia syndrome, and dyskeratosis congenita (DC) suggesting that all of these conditions share at least some common pathogenic mechanisms; they have thus been termed "ribosomopathies." 6 In addition, evidence suggests that the anemia associated with the 5q minus (5qϪ) syndrome (or myelodysplastic syndrome with loss of all or part of chromosome 5q [del(5q) MDS]), a distinct subtype of myelodysplastic syndrome results from somatic heterozygous loss of the ribosomal protein gene RPS14 in hematopoietic stem cells. 7,8 Efforts to understand why ribosomal protein haploinsufficiencies have such a specific and profound effect on erythroid development at the molecular level have focused on the activation and stabilization of p53 in response to ribosomal stress. 9 However, the precise mechanisms governing how p53 stabilization occurs in response to ribosomal protein haploinsufficiency have not been clearly defined. Furthermore, not all bone marrow samples from patients with del(5q) MDS or DBA sh...

Mitosis is a delicate event that must be executed with high fidelity to ensure genomic stability. Recent work has provided insight into how mitotic errors shape cancer genomes by driving both numerical and structural alterations in chromosomes that contribute to tumor initiation and progression. Here, we review the sources of mitotic errors in human tumors and their effect on cell fitness and transformation. We discuss new findings that suggest that chromosome missegregation can produce a proinflammatory environment and impact tumor responsiveness to immunotherapy. Finally, we survey the vulnerabilities exposed by cell division errors and how they can be exploited therapeutically.

Purpose To determine if phosphodiesterase 5 (PDE5) inhibitors can augment immune function in head and neck cancer patients through inhibition of myeloid derived suppressor cells (MDSCs). Experimental Design We performed a randomized, prospective, double blinded, placebo controlled, phase II clinical trial to determine the in vivo effects of systemic PDE5 inhibition on immune function in head and neck squamous cell carcinoma (HNSCC) patients. Results Tadalafil augmented immune response, increasing ex vivo T cell expansion to a mean 2.4 fold increase compared to 1.1 fold in control patients (P= 0.01), reducing peripheral MDSC numbers to mean 0.81 fold change compared to a 1.26 fold change in control patients (P=0.001), and increasing general immunity as measured by delayed type hypersensitivity response (P=0.002). Tumor specific immunity in response to HNSCC tumor lysate was augmented in tadalafil treated patients (P=0.04). Conclusions These findings demonstrate that tadalafil augments general and tumor-specific immunity in HNSCC patients and has therapeutic potential in HNSCC. Evasion of immune surveillance and suppression of systemic and tumor specific immunity is a significant feature of head and neck cancer development. This study demonstrates that a PDE5 inhibitor, tadalafil, can reverse tumor specific immune suppression in head and neck cancer patients, with potential for therapeutic application.

In patients with oropharyngeal carcinoma uniformly treated with chemoradiation, the presence of HPV is a favorable prognostic indicator with respect to recurrence and overall survival. However, advanced T stage was an independent risk factor for recurrence and death that can to some degree offset this benefit.

Evidence supporting prophylactic swallow exercises for patients with head and neck cancer (HNC) has not been universally demonstrated. This RCT examined diet level, feeding tube use, swallow function, and quality of life (QOL) of patients undergoing chemoradiotherapy who performed prophylactic swallowing exercises. Sixty HNC patients were randomized into exercise versus control groups. Swallowing, oromotor, toxicity, and QOL data were recorded (baseline, 3, 6, 12, 24 months). Physiological swallow function was examined at baseline and 3 months. Swallow exercises were completed twice daily. Oral intake at 3 months was 10% better in the exercise group, which was not statistically significant (p = 0.49). Significant (p < 0.05) differences in secondary outcomes including oromotor function, pharyngeal impairment, oral pharyngeal swallow efficiency, and incisal opening were noted at early time points (3–6 months) in the exercise group. Possible positive early improvements in swallow function are associated with swallowing exercises, although these improvements are not significant longer term.

Despite increasing evidence of benefit from adjuvant chemotherapy, older women with breast cancer are commonly given less aggressive treatment than younger patients. Conflicting prior data regarding age-related toxicity prompted this prospective study. Forty-four women (aged 35-79 years) with early-stage breast cancer were treated with four cycles of adjuvant therapy with doxorubicin 60 mg/m2 i.v. and cyclophosphamide 600 mg/m2 i.v. every 21 days. They were monitored for myelosuppression, cardiotoxicity, and decrease in quality of life. Pharmacokinetics were analyzed using cycle 1 plasma samples. Bone marrow granulocyte and macrophage colony-forming units (CFU-GM) were assayed in vitro for dose response to 4-hydroperoxycyclophosphamide and doxorubicin before cycle 1. There was moderate evidence of age-related decrease in nadir absolute neutrophil count (ANC) when age was viewed as a continuous variable. On average there was a 10/microliter drop in cycle 1 nadir ANC for every year increase in age (p = 0.02). However, when age was viewed as a categorical variable (age < 65 vs. > or = 65 years), a similar proportion of women in each group reached an ANC < 100 (18% vs. 19%). Neither neutropenic complications, alteration in cardiac function, nor change in quality of life scores were significantly age related (p > 0.12). Pharmacokinetic analyses did not demonstrate age-related differences in the clearance of either doxorubicin or cyclophosphamide (p > 0.8). Pharmacodynamic analysis of individual patient bone marrow progenitor cell sensitivity did not reveal any correlation with age (p > 0.48). In women undergoing adjuvant therapy for breast cancer, no clinically significant age-related trends in toxicity were observed. These data suggest that older age alone should not exclude patients from receiving adjuvant therapy with doxorubicin and cyclophosphamide.

PURPOSE We evaluated the addition of bevacizumab, a humanized monoclonal antibody that targets vascular endothelial growth factor, to platinum-based chemotherapy in recurrent or metastatic squamous cell carcinoma of the head and neck (SCCHN). PATIENTS AND METHODS Patients with chemotherapy-naïve (or with prior platinum as part of multimodal therapy completed ≥ 4 months earlier) recurrent or metastatic SCCHN were randomly assigned to receive a platinum-based chemotherapy doublet with or without bevacizumab 15 mg/kg given intravenously every 3 weeks until disease progression. Chemotherapy could be discontinued after six cycles if a maximum response was achieved. RESULTS The study randomly assigned 403 patients. Median overall survival (OS) was 12.6 months with bevacizumab plus chemotherapy (BC) and 11.0 months with chemotherapy alone (hazard ratio, 0.87; 95% CI, 0.70 to 1.09; P = .22). At 2, 3, and 4 years, the OS rates were 25.2% v 18.1%, 16.4% v 10.0%, and 11.8% v 6.4% for BC versus chemotherapy, respectively. In an analysis of 365 eligible patients who started treatment, the hazard ratio was 0.82 (95% CI, 0.65 to 1.04; P = .10), with a median OS of 14.2 months on BC v 11.1 months on chemotherapy. Median progression-free survival with BC was 6.0 months v 4.3 months with chemotherapy ( P = .0014). Overall response rates were 35.5% with BC and 24.5% with chemotherapy ( P = .016). There was increased toxicity, including a higher rate of treatment-related grade 3 to 5 bleeding events (6.7% v 0.5%; P < .001) and treatment-related deaths (9.3% v 3.5%; P = .022) with BC versus chemotherapy. CONCLUSION The addition of bevacizumab to chemotherapy did not improve OS but improved the response rate and progression-free survival with increased toxicities. These results encourage biomarker-driven studies of angiogenesis inhibitors with better toxicity profiles in select patients with SCCHN.