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Gamma-Hydroxybutyrate (GHB) is an endogenous short-chain fatty acid formed from Gamma-aminobutyric acid (GABA). Clinically, GHB is marketed in the United States as Xyrem to treat narcolepsy with cataplexy and in Europe for the treatment of alcohol withdrawal and narcolepsy. However, the illicit use and abuse of GHB occurs due to its sedative/hypnotic and euphoric effects. Monocarboxylate transporters (MCTs and SMCTs) are integral membrane proteins that control the bidirectional transport of endogenous substrates including lactate, acetate and pyruvate. They have also been found to transport and mediate the clearance and distribution of GHB. MCTs demonstrate a wide tissue distribution, including brain, kidney, liver, and intestine, all of which play an important role in determining the disposition of GHB. Sex differences in drug elimination pathways contribute to the wide range of inter-individual variability observed between sexes with respect to drug disposition and effect. Sex differences in MCT expression have been observed in the brain, muscle, liver and kidney with variations potentially driven by sex hormones; however, there is an absence of information on how these expression differences translate into sex differences in GHB toxicokinetics. The objective of this study was to evaluate sex differences and the influence of the estrus cycle on GHB toxicokinetics after IV administration. Our hypothesis is that renal clearance and toxicokinetics will vary over the estrus cycle. Estrus cycle stage in female rats was determined by vaginal lavage prior to GHB administration. Ovariectomized (OVX) females were included in the study to evaluate GHB toxicokinetics in the absence of female sex hormones. Our results demonstrated that sex and the estrus cycle influence GHB toxicokinetics. Total and renal clearance varies over the estrus cycle with the highest renal clearance observed in proestrus females. In contrast, males and OVX females demonstrated significantly lower renal clearance. These results suggest that GHB toxicity and risk of overdose varies over the estrus cycle due to expression changes in renal MCTs and SMCTs. Future studies will evaluate higher GHB doses to determine the role of sex hormones in GHB overdose and fatality. In addition, hormone replacement studies will be conducted to confirm the role of individual sex hormones on GHB toxicokinetics.

Lung cancer is the second most common cancer in both men and women around the world, and 85% of it is non-small cell lung cancer (NSCLC). It is estimated that in 2020, there will be 228,820 cases of lung cancer and 135,720 deaths from lung (American Cancer Society, 2020). The prognosis of lung cancer is poor ( Traditionally, the most commonly used in vitro method for screening therapeutic drugs is monolayer cell cultures, which are reproducible, convenient and of low cost. However, monolayer cell culture models are unable to reproduce many properties of in vivo solid tumors such as the morphological features and the microenvironment including cellular heterogeneity, cell-cell interactions, and gradients of oxygen, pH, and nutrients. Consequently, excessive ineffective drug candidates would proceed to animal studies, which would prolong the time for drug development and increase the overall cost of drug discovery. In consideration of the foregoing, in vitro models of cancer based on three-dimensional multicellular spheroids (MCS) have been developed in our group to characterize drug candidates and drug delivery systems. Compared to monolayer cells, the multicellular spheroids can better simulate drug penetration and drug resistance in solid tumors. Therefore, the multicellular spheroids represent a more clinically relevant in vitro model to evaluate the efficacy of anticancer drugs. This project aims to characterize MCS of lung cancer cells as an improved platform to evaluate drug candidates against lung cancer. Cell viability assays on cisplatin, carboplatin, gemcitabine, and doxorubicin have been conducted to compare the anticancer activities between conventional monolayer cells and the corresponding MCS of human lung cancer cell lines, A549 and A549-iRFP (fluorescently labeled A549 cells). Higher concentrations of the tested anticancer drugs is consistently needed to inhibit 50% the cell viability in MCS than the corresponding monolayer cells of A549 and A549-iRFP. Cycled dosing schedules based on guidelines for NSCLC from National Comprehensive Cancer Network have been designed and used to treat A549-iRFP MCS. The A549-iRFP MCS have been exposed to anticancer drugs either continuously, or in pulsed concentrations according to the drugs’ pharmacokinetics (PK). The continuous drug exposure has been found to inhibit more cell growth in MCS than the corresponding PK-mimetic drug exposure. Such phenomenon would bring significant positive bias to the activity of many anticancer drug candidates during their early discovery and development. Taken together, MCS of A549 and A549 iRFP cells better represent the efficacy of anticancer drugs in clinic than the monolayer. MCS can also be used to evaluate anticancer drug candidates by pulsed drug exposure based on their pharmacokinetics, and by commonly used cycled dosing regiments to better predict their efficacy in clinical settings.

Recent strategies for anticancer drug design have been focused on utilizing antibody as a drug or targeted moiety for targeted drug delivery. Antibody−drug conjugates (ADCs) have become a promising new class of targeted therapeutic agents for treatment of cancer. ADCs are designed to preferentially direct a cytotoxic drug to a cell-surface antigen recognized by an antibody. However, there are some challenges in developing ADCs, such as limited solid tumor penetration, high manufacturing costs and antibody-drug stoichiometry. Smaller molecules such as peptides have been shown to specifically bind to cancer related targets. These peptides can be used to form peptide-drug conjugates (PDCs) to overcome above-mentioned drawbacks presented by ADCs. In this study, it was hypothesized that novel synthesized PDCs can be a strategy for breast cancer therapy. HER2 specific binding peptides, MARAKE and MARSGL, were modified by addition of a cysteine at C-terminus. The modified peptides were coupled with monomethylauristatin E (MMAE) by using maleimidocaproyl (MC) as a non-cleavable linker to form peptide-drug conjugates (YW1, YW2) and maleimidocaproyl-valine-citrulline (MC-VC) as a cleavable linker to form peptide-drug conjugates (YW3 and YW4). The peptides, peptide-drug conjugates and MC-MMAE, MC-VC-MMAE were characterized using ESI-MS and purified by using high-performance liquid chromatography (HPLC). Cellular uptake study was performed to determine binding specificity and internalization of two HER2 specific peptides and cysteine-modified peptides (MARAKEC, MARSGLC). In vitro cell viability assay was conducted to assess the cytotoxicity and determine the targeting specificity as well as the potency of the peptide-drug conjugates. The purity of each compound was greater than 90%. Internalization of both HER2 specific binding peptides and cysteine-modified peptides were significantly higher than random peptides in HER2 over-expressed cell lines, MDA-MB361 and ZR75, while negligible uptake in HER2 negative cell line, HEK293. MC linked PDCs showed similar cytotoxicity as peptide in all cell lines; while MC-VC linked PDCs have higher cytotoxicity than MMAE in HER2 positive cell line and significant lower cytotoxicity than MMAE in normal cell line HEK293. However, PDCs with MC link do not show significant difference in cytotoxicity compared to the peptide in all cell lines. In conclusion, specificity of HER2 binding for both peptides was preserved after modification with cysteine. The derivation of MMAE to link drug and peptide played a crucial role in the anticancer activity. Peptide-MMAE conjugates with cleavable linker showed a promising targeting capability for delivery of MMAE to HER2 overexpressed cancer cells.

As people age they are more likely to develop chronic conditions and will tend to be on multiple medications for long periods of time to manage those conditions. Some of these medications have side effects that are anticholinergic in nature. These side effects can impact different parts of the body including the central nervous system. As people enter their later years the permeability of the blood brain barrier increases, increasing their risk of these kinds of side effects. Sleep related disorders occur at a higher frequency in the older adults than in younger adults. This is a concern for older adults because poor sleep quality has been linked to chronic health conditions as well as declining function and quality of life. Although some medications are known to cause insomnia there has not been any work done to look at how an accumulative influence of anticholinergic burden may be influencing sleep despite their known influence on the central nervous system. The purpose of this research is to see if the anticholinergic burden of the medications is related to self-reported sleep quality. Fourteen outreach events targeting Medicare beneficiaries were conducted during the 2014 Medicare open enrollment window in northern/central California. Medication therapy management (MTM) services were provded by trained student pharmacists under the supervision of licensed pharmacists where demographic and medication information were collected. Beneficiaries who reported having trouble sleeping had higher anticholinergic burden than those who did not. Beneficiaries who only reported difficulty falling asleep had higher anticholinergic burden than those who did not. Correlations between anticholinergic burden and the number of nights with trouble sleeping was positive but this association only reached statistical significance with definite anticholinergic burden. Linear regression did not suggest that anticholinergic burden was a predictor of the number of nights with difficulty sleeping.