The Influence of Vitamin D on Mammographic Density: Results from CALGB 70806 (Alliance) a Randomized Clinical Trial.

Current therapies for breast cancer prevention only prevent estrogen receptor positive (ER+) disease and toxicity limits use of these agents. Vitamin D is a potential prevention therapy for both ER+ and ER- disease and is safe with few side effects. This study evaluates the effect of 1-year of vitamin D supplementation on mammographic density (MD), a biomarker of breast cancer risk in a multicenter randomized controlled trial. Premenopausal women with ≥25% MD and no history of cancer were randomly assigned to 2,000 international units (IU) of vitamin D or placebo orally daily for 1 year. Change in percent MD was evaluated using Cumulus software after all participants completed treatment. Three hundred women enrolled between January 2011 and December 2013 with a mean age of 43 and diverse ethnicity [14% Hispanic, 12% African American (AA)]. Supplementation significantly increased vitamin D levels compared with placebo (14.5 ng/mL vs. -1.6 ng/mL; P < 0.0001) with all participants on the vitamin D arm achieving vitamin D sufficiency at 12 months. Vitamin D was safe and well tolerated. After adjustment for baseline MD, the mean between-arm difference (vitamin D vs. placebo) at 1 year was -0.75 (-0.26, 1.76; P = 0.56). A greater effect was seen for women with ≥50% MD and AA women, although neither reached significance. This randomized controlled trial demonstrated significant improvement in vitamin D levels with 2,000 IU for 1 year, with 100% of supplemented women achieving sufficiency. However, a null effect was seen regarding change in MD for premenopausal women (the primary outcome of the study). PREVENTION RELEVANCE: Current therapies for breast cancer prevention only prevent estrogen receptor positive (ER+) disease and are underutilized due to toxicity and side effects. Vitamin D is a potential prevention therapy for both ER+ and ER- disease and is safe with few side effects.

Distinct signals in medial and lateral VTA dopamine neurons modulate fear extinction at different times.

Dopamine (DA) neurons are to encode reward prediction error (RPE), in addition to other signals, such as salience. While RPE is known to support learning, the role of salience in learning remains less clear. To address this, we recorded and manipulated VTA DA neurons in mice during fear extinction. We applied deep learning to classify mouse freezing behavior, eliminating the need for human scoring. Our fiber photometry recordings showed DA neurons in medial and lateral VTA have distinct activity profiles during fear extinction: medial VTA activity more closely reflected RPE, while lateral VTA activity more closely reflected a salience-like signal. Optogenetic inhibition of DA neurons in either region slowed fear extinction, with the relevant time period for inhibition differing across regions. Our results indicate salience-like signals can have similar downstream consequences to RPE-like signals, although with different temporal dependencies.

Internal states and extrinsic factors both determine monkey vocal production.

A key question for understanding speech evolution is whether or not the vocalizations of our closest living relatives-nonhuman primates-represent the precursors to speech. Some believe that primate vocalizations are not volitional but are instead inextricably linked to internal states like arousal and thus bear little resemblance to human speech. Others disagree and believe that since many primates can use their vocalizations strategically, this demonstrates a degree of voluntary vocal control. In the current study, we present a behavioral paradigm that reliably elicits different types of affiliative vocalizations from marmoset monkeys while measuring their heart rate fluctuations using noninvasive electromyography. By modulating both the physical distance between marmosets and the sensory information available to them, we find that arousal levels are linked, but not inextricably, to vocal production. Different arousal levels are, generally, associated with changes in vocal acoustics and the drive to produce different call types. However, in contexts where marmosets are interacting, the production of these different call types is also affected by extrinsic factors such as the timing of a conspecific's vocalization. These findings suggest that variability in vocal output as a function of context might reflect trade-offs between the drive to perpetuate vocal contact and conserving energy.

Reward magnitude tracking by neural populations in ventral striatum.

Evaluation of the magnitudes of intrinsically rewarding stimuli is essential for assigning value and guiding behavior. By combining parametric manipulation of a primary reward, medial forebrain bundle (MFB) microstimulation, with functional magnetic imaging (fMRI) in rodents, we delineated a broad network of structures activated by behaviorally characterized levels of rewarding stimulation. Correlation of psychometric behavioral measurements with fMRI response magnitudes revealed regions whose activity corresponded closely to the subjective magnitude of rewards. The largest and most reliable focus of reward magnitude tracking was observed in the shell region of the nucleus accumbens (NAc). Although the nonlinear nature of neurovascular coupling complicates interpretation of fMRI findings in precise neurophysiological terms, reward magnitude tracking was not observed in vascular compartments and could not be explained by saturation of region-specific hemodynamic responses. In addition, local pharmacological inactivation of NAc changed the profile of animals' responses to rewards of different magnitudes without altering mean reward response rates, further supporting a hypothesis that neural population activity in this region contributes to assessment of reward magnitudes.

Molecular fMRI of Serotonin Transport.

Reuptake of neurotransmitters from the brain interstitium shapes chemical signaling processes and is disrupted in several pathologies. Serotonin reuptake in particular is important for mood regulation and is inhibited by first-line drugs for treatment of depression. Here we introduce a molecular-level fMRI technique for micron-scale mapping of serotonin transport in live animals. Intracranial injection of an MRI-detectable serotonin sensor complexed with serotonin, together with serial imaging and compartmental analysis, permits neurotransmitter transport to be quantified as serotonin dissociates from the probe. Application of this strategy to much of the striatum and surrounding areas reveals widespread nonsaturating serotonin removal with maximal rates in the lateral septum. The serotonin reuptake inhibitor fluoxetine selectively suppresses serotonin removal in septal subregions, whereas both fluoxetine and a dopamine transporter blocker depress reuptake in striatum. These results highlight promiscuous pharmacological influences on the serotonergic system and demonstrate the utility of molecular fMRI for characterization of neurochemical dynamics.

Stepwise development of a cancer care delivery research study to evaluate the prevalence of virus infections in cancer patients.

BACKGROUND: SWOG initiated a cancer care delivery research study of virus infection rates among newly diagnosed cancer patients. This study will inform viral screening guidelines in oncology clinics. METHODS: In a first step 'vanguard' phase, we evaluated the feasibility of multiple study procedures. Site investigators were surveyed to obtain feedback on study implementation. RESULTS: Much higher enrollment occurred at sites where all physicians participated and viral testing was performed as routine practice. These procedures will be required going forward. Additional protocol changes based on site investigator input were implemented. CONCLUSION: This multistep protocol design process illustrates how cancer care delivery research studies can adapt to real-world strategies and procedures that exist at community clinics where the predominance of cancer patients are treated.

Effect of Vitamin D Supplementation on Breast Cancer Biomarkers: CALGB 70806 (Alliance) Study Design and Baseline Data.

One in eight women will develop breast cancer over their lifetime with 230,000 women diagnosed in 2015. For this reason, breast cancer prevention efforts are essential. Vitamin D, with anticancer properties, may have a role in prevention of some cancers, including breast cancer. This report discusses the rationale, study protocol, and baseline data for a clinical trial of vitamin D and its effects on breast cancer biomarkers. This study was a randomized controlled trial designed to evaluate the effect of a fixed dose of vitamin D on specfic breast cancer biomarkers. Study participants were randomized to take either vitamin D or placebo for a period of 1 year. All participants had mammograms and blood drawn for serum biomarkers. A subset of participants underwent random periareolar fine needle aspiration to draw tissue for biomarkers. From January 2011 to December 2013, 300 premenopausal women, aged 59 or younger, were recruited from 41 institutions across the United States. A total of 102 women underwent random periareolar fine needle aspiration. The last subject completed the trial in January 2015. Baseline vitamin D levels for all participants ranged from 4-72 ng/mL, with 62% of participants being vitamin D deficient at enrollment (≥30 ng/mL or ≥75 nmo-l/L). The mean body mass index was 27.0 kg/m2 (range 15.1-53.6 kg/m2). 14% and 11.7% of participants were Hispanic or African American, respectively. Accrual and enrollment of participants is feasible for this type of multi-center prevention trial, and it can readily be carried out in a cooperative group setting.

Expression of PKCα, PKCε, and P-gp in epithelial ovarian carcinoma and the clinical significance.

AIM: To inspect the expression of two protein kinase PKC isozyme hypotype PKCα and PKCε in the epithelial ovarian carcinoma tissue, and investigate their relation with multi-drug resistance with P-glycoprotein (P-gp) medium. MATERIALS AND METHODS: Adopted immunohistochemistry SP method to determine expression of PKCα, PKCε, and P-gp in 64 cases of epithelial ovarian carcinoma, 18 cases of epithelial borderline ovarian carcinoma, 15 cases of epithelial ovarian benign tumor, and 15 cases of normal ovarian tissue. RESULTS: The expression of PKCα, PKCε, and P-gp in the epithelial ovarian carcinoma is obviously higher than expression in the normal, benign. and borderline epithelial ovarian carcinoma; the expression of PKCα, PKCε, and P-gp in the recurrent carcinoma tissue is obviously higher than that in the person with initial treatment; the expression of above-mentioned three indicators in epithelial ovarian carcinoma is unrelated with the pathological type, pathological grade, and clinical stage during initial treatment of the carcinoma; there is a close relation among PKCα, PKCε, and P-gp in epithelial ovarian carcinoma (p < 0.01). It is indicated through research that PKCα, PKCε, and P-gp is related with the survival time and poor prognosis of the patient of epithelial ovarian carcinoma, i.e., the positive expression rate of PKCα, PKCε, and P-gp of the person with recurrent carcinoma is higher than that of the person without recurrent car- cinoma (p < 0.05). However, the survival rate of the patients with positive expression of three indicators is remarkably lower than those with negative expression (p < 0.05). CONCLUSION: There is a consistency between expression of PKCα, PKCε, and P-gp in the epithelial ovarian carcinoma, which indicates that the expression of both plays an important role in generation of drug resistance in chemotherapy of ovarian carcinoma with P-gp medium. Joint detection of three indicators has an active guiding role in judgment of the therapeutic effect of clinical chemotherapy and prognosis estimation of the patient.

Molecular-level functional magnetic resonance imaging of dopaminergic signaling.

We demonstrate a technique for mapping brain activity that combines molecular specificity and spatial coverage using a neurotransmitter sensor detectable by magnetic resonance imaging (MRI). This molecular functional MRI (fMRI) method yielded time-resolved volumetric measurements of dopamine release evoked by reward-related lateral hypothalamic brain stimulation of rats injected with the neurotransmitter sensor. Peak dopamine concentrations and release rates were observed in the anterior nucleus accumbens core. Substantial dopamine transients were also present in more caudal areas. Dopamine-release amplitudes correlated with the rostrocaudal stimulation coordinate, suggesting participation of hypothalamic circuitry in modulating dopamine responses. This work provides a foundation for development and application of quantitative molecular fMRI techniques targeted toward numerous components of neural physiology.

The free energy profile of tubulin straight-bent conformational changes, with implications for microtubule assembly and drug discovery.

αß-tubulin dimers need to convert between a 'bent' conformation observed for free dimers in solution and a 'straight' conformation required for incorporation into the microtubule lattice. Here, we investigate the free energy landscape of αß-tubulin using molecular dynamics simulations, emphasizing implications for models of assembly, and modulation of the conformational landscape by colchicine, a tubulin-binding drug that inhibits microtubule polymerization. Specifically, we performed molecular dynamics, potential-of-mean force simulations to obtain the free energy profile for unpolymerized GDP-bound tubulin as a function of the ∼12° intradimer rotation differentiating the straight and bent conformers. Our results predict that the unassembled GDP-tubulin heterodimer exists in a continuum of conformations ranging between straight and bent, but, in agreement with existing structural data, suggests that an intermediate bent state has a lower free energy (by ∼1 kcal/mol) and thus dominates in solution. In agreement with predictions of the lattice model of microtubule assembly, lateral binding of two αß-tubulins strongly shifts the conformational equilibrium towards the straight state, which is then ∼1 kcal/mol lower in free energy than the bent state. Finally, calculations of colchicine binding to a single αß-tubulin dimer strongly shifts the equilibrium toward the bent states, and disfavors the straight state to the extent that it is no longer thermodynamically populated.

Effects of solution concentration on the physicochemical properties of a polymeric anticancer therapeutic.

Poly(γ-glutamyl-glutamate) paclitaxel (PGG-PTX) is a series of eighteen semiflexible polymer-drug constructs varying in PTX loading fraction (f(PTX) of 0.18, 0.24, and 0.37) and spatial PTX arrangement (uniform, "even" and "random"; clustered, "clusters" and "ends"; concentrated, "ends" and "side"). Structural properties of PGG-PTX in dilute and concentrated conditions are determined from coarse-grained molecular dynamics (MD) simulations. Since PGG-PTX does not have a specific conformation, MD simulations were run until minimal structural deviations persisted. Root-mean-square deviation (RMSD) clustering was then used to determine the significant, unique characteristic conformations. Results show that dilute PGG-PTX undergoes a globule-to-filament transition with respect to increasingly denser PTX arrangements. While a similar transition is apparent in concentrated conditions, PGG-PTX tends to be more filamentous on the whole. PGG-PTX is also more rigid in concentrated conditions, and a higher PTX loading fraction leads to decreased flexibility. In general, the dilute "ends", "middle", and "side" PGG-PTX molecules at f(PTX) = 0.18 and 0.24 prove to be the most efficaciously promising and are recommended for future biological testing. This study demonstrates the practicality of molecular modeling toward understanding structural behavior of an anticancer therapeutic in different solution concentrations.

Aggregation properties of a polymeric anticancer therapeutic: a coarse-grained modeling study.

The effects of paclitaxel (PTX) loading fraction and spatial PTX arrangement on poly(γ-glutamyl-glutamate) paclitaxel (PGG-PTX) aggregation were explored using coarse-grained molecular dynamics. Results show that the PTX loading fraction does not significantly impact aggregation, and the spatial PTX arrangement only affects aggregation at more concentrated PTX arrangements. Overall, the f(PTX) = 0.37 'ends' and f(PTX) = 0.18 'even' PGG-PTX systems exhibit the highest aggregation and the 'middle' and 'side' systems the lowest.

Coarse-grained modeling study of nonpeptide RGD ligand density and PEG molecular weight on the conformation of poly(γ-glutamyl-glutamate) paclitaxel conjugates.

Molecular shape, flexibility, and surface hydrophilicity are thought to influence the ability of nanoparticles to cross biological barriers during drug delivery. In this study, coarse-grained (CG) molecular dynamics (MD) simulations were used to study these properties of a polymer-drug construct in potential clinical development: poly(γ-glutamyl-glutamate)-paclitaxel-poly(ethylene glycol) nonpeptide RGD (PGG-PTX-PEG-npRGD), a linear glutamyl-glutamate polymer with paclitaxel and poly(ethylene glycol)-nonpeptide RGD side groups. It was hypothesized that the PEG molecular weight (MW) (500 Da; 1,000 Da; and 2,000 Da) and nonpeptide RGD ligand density (4, 8, 12, and 16 per molecule), respectively, may have advantageous effects on the shape, flexibility, and surface hydrophilicity of PGG-PTX-PEG-npRGD. Circular dichroism spectroscopy was used to suggest initial structures for the all-atom (AA) models of PGG-PTX-PEG-npRGD, which were further converted to CG models using a commercially available mapping algorithm. Due to its semi-flexibility, PGG-PTX-PEG-npRGD is not limited to one specific conformation. Thus, CG MD simulations were run until statistical equilibrium, at which PGG-PTX-PEG-npRGD is represented as an ensemble of statistically similar conformations. The size of a PGG-PTX-PEG-npRGD molecule is not affected by the PEG MW or the nonpeptide RGD density, but higher PEG MW results in increased surface density of a PGG-PTX-PEG-npRGD molecule. Most PGG-PTX-PEG-npRGD shapes are globular, although filamentous shapes were also observed in the PEG500 and PEG1000 molecules. PEG500 and PEG1000 molecules are more flexible than PEG2000 systems. A higher presence of npRGD ligands results in decrease surface hydrophilicity of PGG-PTX-PEG-npRGD. These results indicate that the PGG-PTX-PEG1000-npRGD(4) and PGG-PTX-PEG1000-npRGD(8) molecules are the most efficacious candidates and are further recommended for experimental preclinical studies.

Characterization of a clinical polymer-drug conjugate using multiscale modeling.

The molecular conformation of certain therapeutic agents has been shown to affect the ability to gain access to target cells, suggesting potential value in defining conformation of candidate molecules. This study explores how the shape and size of poly-γ-glutamyl-glutamate paclitaxel (PGG-PTX), an amphiphilic polymer-drug with potential chemotherapeutic applications, can be systematically controlled by varying hydrophobic and hydrophilic entities. Eighteen different formulations of PGG-PTX varying in three PTX loading fractions (f(PTX)) of 0.18, 0.24, and 0.37 and six spatial arrangements of PTX ('clusters', 'ends', 'even', 'middle', 'random', and 'side') were explored. Molecular dynamics (MD) simulations of all-atom (AA) models of PGG-PTX were run until a statistical equilibrium was reached at 100 ns and then continued as coarse-grained (CG) models until a statistical equilibrium was reached at an effective time of 800 ns. Circular dichroism spectroscopy was used to suggest initial modeling configurations. Results show that a PGG-PTX molecule has a strong tendency to form coil shapes, regardless of the PTX loading fraction and spatial PTX arrangement, although globular shapes exist at f(PTX) = 0.24. Also, less uniform PTX arrangements such as 'ends', 'middle', and 'side' produce coil geometries with more curvature. The prominence of coil shapes over globules suggests that PGG-PTX may confer a long circulation half-life and high propensity for accumulation to tumor endothelia. This multiscale modeling approach may be advantageous for the design of cancer therapeutic delivery systems. © 2010 Wiley Periodicals, Inc. Biopolymers 93: 936-951, 2010.

Promising newer molecular-targeted therapies in head and neck cancer.

Head and neck cancer (HNC) is the fifth most common cancer in the world. In the US alone, HNC accounts for 3-5% of all malignancies annually. Squamous cell carcinoma arising from the mucosa of the upper aerodigestive tract is the most common type of HNC and accounts for 90% of HNC diagnoses. Despite continued advances in the therapeutic options, the disease-free survival, functional outcome, toxicity of therapy and overall survival have remained less than optimal for patients with locally advanced, recurrent or metastatic disease. Therefore, new approaches for the treatment of patients with HNC, particularly patients with advanced stage, are clearly needed. Among the new therapies, molecular-targeted and biological therapies have gained special attention. While clinical trial data support the use of epidermal growth factor receptor (EGFR) inhibition in metastatic and locally advanced HNC, numerous trials are seeking to establish a clear role for new therapies targeting EGFR, the receptor for the type I insulin-like growth factor, as well as anti-angiogenesis agents.

Reversal of chronic inflammatory pain by acute inhibition of Ca2+/calmodulin-dependent protein kinase II.

Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) is a major protein kinase that is capable of regulating the activities of many ion channels and receptors. In the present study, the role of CaMKII in the complete Freund's adjuvant (CFA)-induced inflammatory pain was investigated. Intraplantarly injected CFA was found to induce spinal activity of CaMKII (phosphorylated CaMKII), which was blocked by KN93 [[2-[N-(2-hydroxyethyl)]-N-(4-methoxybenzenesulfonyl)]amino-N-(4-chlorocinnamyl)-N-methylbenzylamine)], a CaMKII inhibitor. Pretreatment with KN93 (i.t.) dose-dependently prevented the development of CFA-induced thermal hyperalgesia and mechanical allodynia. Acute treatment with KN93 (i.t.) also dose-dependently reversed CFA-induced thermal hyperalgesia and mechanical allodynia. The action of KN93 started in 30 min and lasted for at least 2 to 4 h. KN92 (45 nmol i.t.) [2-[N-(4-methoxybenzenesulfonyl)]amino-N-(4-chlorocinnamyl)-N-methylbenzylamine], an inactive analog of KN93, showed no effect on CFA-induced CaMKII activation, allodynia, or hyperalgesia. Furthermore, our previous studies identified trifluoperazine, a clinically used antipsychotic drug, to be a potent CaMKII inhibitor. Inhibition of CaMKII activity by trifluoperazine was confirmed in the study. In addition, trifluoperazine (i.p.) dose-dependently reversed CFA-induced mechanical allodynia and thermal hyperalgesia. The drug was also effectively when given orally. In conclusion, our findings support a critical role of CaMKII in inflammatory pain. Blocking CaMKII or CaMKII-mediated signaling may offer a novel therapeutic target for the treatment of chronic pain.

Systems analysis of PKA-mediated phosphorylation gradients in live cardiac myocytes.

Compartmentation and dynamics of cAMP and PKA signaling are important determinants of specificity among cAMP's myriad cellular roles. Both cardiac inotropy and the progression of heart disease are affected by spatiotemporal variations in cAMP/PKA signaling, yet the dynamic patterns of PKA-mediated phosphorylation that influence differential responses to agonists have not been characterized. We performed live-cell imaging and systems modeling of PKA-mediated phosphorylation in neonatal cardiac myocytes in response to G-protein coupled receptor stimuli and UV photolysis of "caged" cAMP. cAMP accumulation was rate-limiting in PKA-mediated phosphorylation downstream of the beta-adrenergic receptor. Prostaglandin E1 stimulated higher PKA activity in the cytosol than at the sarcolemma, whereas isoproterenol triggered faster sarcolemmal responses than cytosolic, likely due to restricted cAMP diffusion from submembrane compartments. Localized UV photolysis of caged cAMP triggered gradients of PKA-mediated phosphorylation, enhanced by phosphodiesterase activity and PKA-mediated buffering of cAMP. These findings indicate that combining live-cell FRET imaging and mechanistic computational models can provide quantitative understanding of spatiotemporal signaling.

Phosphorylation: a molecular switch in opioid tolerance.

Protein phosphorylation is a key posttranslational modification mechanism controlling the conformation and activity of many proteins. Increasing evidence has implicated an essential role of phosphorylation by several major protein kinases in promoting and maintaining opioid tolerance. We review some of the most recent studies on protein kinase C (PKC), cyclic AMP dependent protein kinase A (PKA), calcium/calmodulin-dependent protein kinase II (CaMKII), protein kinase G (PKG), and G protein receptor kinase (GRK). These kinases act as the molecular switches to modulate opioid tolerance. Pharmacological interventions at one or more of the protein kinases and phosphatases may provide valuable strategies to improve opioid analgesia by attenuating tolerance to these drugs.

Reversal of morphine antinociceptive tolerance and dependence by the acute supraspinal inhibition of Ca(2+)/calmodulin-dependent protein kinase II.

Previous studies have suggested that Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) can modulate opioid tolerance and dependence via its action on learning and memory. In this study, we examined whether CaMKII could directly regulate opioid tolerance and dependence. CaMKII activity was increased after the treatment with morphine (100 mg/kg s.c. or 75 mg s.c. of morphine/pellet/mouse); the effect exhibited a temporal correction with the development of opioid tolerance and dependence. In mice treated with morphine (100 mg/kg s.c.), morphine tolerance and dependence developed in 2 to 6 h. An acute supraspinal administration of KN93 [2-[N-(2-hydroxyethyl)]-N-(4-methoxybenzenesulfonyl)]amino-N-(4-chlorocinnamyl)-N-methylbenzylamine)], a CaMKII inhibitor, was able to dose-dependently reverse the already-established antinociceptive tolerance to morphine (p < 0.001 for 15-30 nmol; not significant for 5 nmol). KN92 [2-[N-(4-methoxybenzenesulfonyl)]amino-N-(4-chlorocinnamyl)-N-methylbenzylamine] (30 nmol i.c.v.), a kinase-inactive analog of KN93, did not affect opioid tolerance. Neither KN92 nor KN93 affected basal nociception or acute morphine antinociception (1-10 nmol i.c.v.). Likewise, dependence on morphine was abolished by the acute administration of KN93, but not KN92, in a dose-dependent manner. Pretreatment of mice with KN93 also prevented the development of morphine tolerance and dependence. The effect of acute CaMKII inhibition was not limited to the particular experimental model, because KN93 also acutely reversed the established opioid tolerance and dependence in mice treated with morphine (75 mg/pellet/mouse s.c.) for 6 days. Taken together, these data strongly support the hypothesis that CaMKII can act as a key and direct factor in promoting opioid tolerance and dependence. Identifying such a direct mechanism may be useful for designing pharmacological treatments for these conditions.

Animal and cellular models of chronic pain.

Chronic pain, especially neuropathic pain and cancer pain, is often not adequately treated by currently available analgesics. Animal models provide pivotal systems for preclinical study of pain. This article reviews some of the most widely used or promising new models for chronic pain. Partial spinal ligation, chronic constriction injury, and L5/L6 spinal nerve ligation represent three of the best characterized rodent models of peripheral neuropathy. Recently, several mouse and rat bone cancer pain models have been reported. Primary or permanent cultures of sensory neurons have been established to study the molecular mechanism of pain, especially for neurotransmitter release and signal transduction. The emerging gene microarray, genomics and proteomics methods may be applied to throughly characterize these cells. Each model is uniquely created with distinct mechanisms, it is therefore essential to report and interpret results in the context of a specific model.