No abstract

Cisplatin, one of the most commonly used anti-cancer drugs, is known to cause inner ear hair cell damage and hearing loss. Despite much investigation into mechanisms of cisplatin-induced hair cell death, little is known about the mechanism whereby cisplatin is selectively toxic to hair cells. Using hair cells of the zebrafish lateral line, we found that chemical inhibition of mechanotransduction with quinine and EGTA protected against cisplatin-induced hair cell death. Furthermore, we found that the zebrafish mutants mariner (myo7aa) and sputnik (cad23) that lack functional mechanotransduction were resistant to cisplatin-induced hair cell death. Using a fluorescent analogue of cisplatin, we found that chemical or genetic inhibition of mechanotransduction prevented its uptake. These findings demonstrate that cisplatin-induced hair cell death is dependent on functional mechanotransduction in the zebrafish lateral line.

Aminoglycoside (AG) antibiotics are widely used to prevent life-threatening infections, and cisplatin is used in the treatment of various cancers, but both are ototoxic and result in loss of sensory hair cells from the inner ear. ORC-13661 is a new drug that was derived from PROTO-1, a compound first identified as protective in a large-scale screen utilizing hair cells in the lateral line organs of zebrafish larvae. Here, we demonstrate, in zebrafish larvae and in mouse cochlear cultures, that ORC-13661 provides robust protection of hair cells against both ototoxins, the AGs and cisplatin. ORC-13661 also prevents both hearing loss in a dose-dependent manner in rats treated with amikacin and the loading of neomycin-Texas Red into lateral line hair cells. In addition, patch-clamp recordings in mouse cochlear cultures reveal that ORC-13661 is a high-affinity permeant blocker of the mechanoelectrical transducer (MET) channel in outer hair cells, suggesting that it may reduce the toxicity of AGs by directly competing for entry at the level of the MET channel and of cisplatin by a MET-dependent mechanism. ORC-13661 is therefore a promising and versatile protectant that reversibly blocks the hair cell MET channel and operates across multiple species and toxins.

The latest World Health Organization International Classification defines papillary thyroid carcinoma by its "follicular cell differentiation...as well as characteristic nuclear changes". However the oxyphilic (Hürthle cell) papillary carcinoma have nuclei which generally resemble the nuclei seen in oxyphilic follicular carcinomas, and such oxyphilic papillary tumors may behave more aggressively than typical papillary cancers. To further characterize these rare tumors, we identified during a 32-year period 22 patients with oxyphilic papillary cancer and compared them with 1,084 patients with typical papillary cancers and 57 patients with oxyphilic follicular cancers treated by the Mayo surgical group during the same time period. Although typical papillary and oxyphilic papillary cancers were comparable with regards to patient age, tumor size and extent, TNM stage, and prognostic score (AGES), there were significant differences. Compared to typical papillary tumors, oxyphilic papillary cancers had fewer neck nodal metastases at primary diagnosis (5% vs 40%, p less than 0.0001), were more often DNA non-diploid (71% vs 21%, p less than 0.001), and after 10 postoperative years had higher rates of both tumor recurrence (28% vs 11%, p less than 0.0001) and cause-specific mortality (1.7% vs 4%, p less than 0.0005). In these four important respects the oxyphilic papillary cancers more resembled the oxyphilic follicular cancers. For oxyphilic follicular cancers, the frequency of initial neck nodal metastases was 7% (cf 5%); 83% of the oxyphilic follicular tumors were non-diploid (cf 71%), and at 10 years postoperatively the tumor recurrence and cause-specific mortality rates were 28% and 18%, insignificantly different from 28% and 17% seen with the oxyphilic papillary cancers.(ABSTRACT TRUNCATED AT 250 WORDS)

DD can be successfully reduced among distressed individuals with T1D with elevated HbA using both education/behavioral and emotion-focused approaches. Reductions in DD are only modestly associated with reductions in HbA. These findings point to the importance of tailoring interventions to address affective, knowledge, and cognitive skills when intervening to reduce DD and improve glycemic control.

Estrogen receptor alpha (ERa) is a ligand-dependent nuclear receptor that is important in breast cancer genesis, behavior and response to hormone-based therapies. A T7 phage display screen against full-length human ERa, coupled with genome-wide exon arrays, was used to identify RAC3 as a putative ERa co-regulator. RAC3 is a Rho family small GTPase that is associated with cytoskeletal rearrangement. We demonstrate a novel role for nuclear RAC3 as an ERa transcriptional activator, with prognostic implications for metastatic disease. Through in vitro and cell-based studies, RAC3 was shown to exist in a GTP-bound state and act as a ligand specific ERa co-activator of E2-induced transcription. Overexpression of RAC3 induced pro-growth and pro-migratory genes that resulted in increased migration of ERapositive breast cancer cells. Chemical inhibition and genetic knockdown of RAC3 antagonized E2-induced cell proliferation, cell migration and ERa mediated gene expression, indicating that RAC3 is necessary for full ERa transcriptional activity. In agreement with the molecular and cellular data, RAC3 overexpression in ERa-positive breast cancers correlated with a significant decrease in recurrence free survival and a significant increase in the odds ratio of metastasis. In conclusion, RAC3 is a novel ERa co-activator that promotes cell migration and has prognostic value for ERa-positive breast cancer metastasis. RAC3 may also be a useful therapeutic target for ERa-positive breast cancers.

We have previously published results from a screen of 1,040 FDA-approved drugs and bioactives (NINDS Custom Collection) for drugs that protect against neomycin-induced hair cell death (Ou et al., J Assoc Res Otolaryngol 10:191-203, 2009). Further evaluation of this drug library identified eight protective drugs that shared a common quinoline scaffold. These drugs were tested further in terms of their protection against other aminoglycosides, as well as their effect on aminoglycoside uptake. All of the eight quinolines that protected against neomycin were found to protect against shortand long-term gentamicin damage protocols. We then tested the structurally related compounds quinoline, isoquinoline, naphthalene, and indole for protective effects. Of these compounds, indole demonstrated a small but significant amount of protection against neomycin, while quinoline and isoquinoline partially protected against long-term gentamicin damage. We examined whether the protective activity of this group of compounds was related to known targets of the quinoline derivatives. The protective effects did not seem linked to either the cholinergic or histaminergic pathways that are regulated by some members of the quinoline family. However, all eight protective drugs were found to reduce the uptake of aminoglycosides into hair cells. Subsequent experiments suggest that reduction of uptake is the primary mechanism of protection among the quinoline drugs.

Hypothesis The zebrafish lateral line can be used to identify small molecules that protect against cisplatin-induced hair cell death. Background Cisplatin is a commonly used chemotherapeutic which causes hearing loss by damaging hair cells of the inner ear. There are currently no FDA-approved pharmacologic strategies for preventing this side effect. The zebrafish lateral line has been used successfully in the past to study hair cell death and protection. Methods In this study we used the zebrafish lateral line to screen a library of 10,000 small molecules for protection against cisplatin-induced hair cell death. Dose-response relationships for identified protectants were determined by quantifying hair cell protection. The effect of each protectant on cisplatin uptake was quantified. Results From this screen we identified two compounds exhibiting dose-dependent protection: Cisplatin Hair Cell Protectant 1 and 2 (CHCP1 and 2). CHCP1 reduced uptake of a fluorescent cisplatin analog suggesting its protective effects may be due to decreased cisplatin uptake. CHCP2 did not affect uptake, which suggests an intracellular mechanism of action. Evaluation of analogs of CHCP2 revealed three additional compounds that significantly reduced cisplatin-induced hair cell death, though none exceed the effectiveness or potency of the parent compound. Conclusion The zebrafish lateral line was used to identify two small molecules that protected against cisplatin-induced hair cell death.