Implications and Efficacy of Aromatase Inhibitors in Combination and Monotherapy for the Treatment of Lung Cancer.

BACKGROUND: Lung tumors express high levels of aromatase enzyme compared to surrounding normal tissue. Inhibition of aromatase has emerged as a recent therapeutic approach for the treatment of breast cancer. However, the role of aromatase inhibition in lung cancer treatment requires further investigation. METHODS: The anti-proliferative effects of aromatase inhibitors were evaluated by MTT assay. Cell migration was assessed using a wound healing assay. The mechanism of cell death was determined using the annexin VFITC/ propidium iodide staining flow cytometry method. The soft agar colony formation assay evaluated cells' capability to form colonies. RESULT: Exemestane and curcumin significantly inhibited the growth of lung cancer cell lines in a dose- and timedependent manner. The IC50 values after 48 hours of treatment with exemestane were 176, 180, and 120 µM in A549, H661, and H1299, respectively. Curcumin IC50 values after 48 hours were 80, 43, and 68 µM in A549, H661, and H1299, respectively. The combined treatment of exemestane or curcumin with cisplatin, raloxifene, and celecoxib resulted in a synergistic effect in the A549 lung cell line with a combination index of less than 1, suggesting synergism. Exemestane resulted in approximately 96% inhibition of wound closure at 100 µM, while curcumin resulted in approximately 63% inhibition of wound closure at 50 µM. Exemestane and curcumin inhibited the formation of cell colonies by reducing the number and size of formed colonies of A549, H661, and H1299 cell lines in a concentration dependent manner. Exemestane and curcumin had significantly induced apoptosis in A549 cells compared to control of untreated cells. CONCLUSION: Aromatase inhibition by exemestane or curcumin had significantly inhibited the growth of lung cancer cell lines, synergized with cisplatin, raloxifene, and celecoxib, suppressed lung cancer cell migratory potential, induced apoptosis, and reduced colony formation of lung cancer cells.

High-throughput screening yields several small-molecule inhibitors of repeat-associated non-AUG translation.

Repeat-associated non-AUG (RAN) translation is a noncanonical translation initiation event that occurs at nucleotide-repeat expansion mutations that are associated with several neurodegenerative diseases, including fragile X-associated tremor ataxia syndrome (FXTAS), ALS, and frontotemporal dementia (FTD). Translation of expanded repeats produces toxic proteins that accumulate in human brains and contribute to disease pathogenesis. Consequently, RAN translation constitutes a potentially important therapeutic target for managing multiple neurodegenerative disorders. Here, we adapted a previously developed RAN translation assay to a high-throughput format to screen 3,253 bioactive compounds for inhibition of RAN translation of expanded CGG repeats associated with FXTAS. We identified five diverse small molecules that dose-dependently inhibited CGG RAN translation, while relatively sparing canonical translation. All five compounds also inhibited RAN translation of expanded GGGGCC repeats associated with ALS and FTD. Using CD and native gel analyses, we found evidence that three of these compounds, BIX01294, CP-31398, and propidium iodide, bind directly to the repeat RNAs. These findings provide proof-of-principle supporting the development of selective small-molecule RAN translation inhibitors that act across multiple disease-causing repeats.

Epidermal growth factor receptor blockade potentiates apoptosis mediated by Paclitaxel and leads to prolonged survival in a murine model of oral cancer.

PURPOSE: Because survival for patients with oral cancer has not improved over the past 25 years, new approaches for treatment are needed. Targeted molecular therapy against epidermal growth factor receptor (EGFR) has shown promise as an adjuvant therapy in preliminary studies in several solid tumors, including head and neck cancer. The objective of this study was to determine the efficacy of paclitaxel and PKI166, a novel inhibitor of EGFR, against oral cavity cancer. EXPERIMENTAL DESIGN AND RESULTS: JMAR human oral cancer cells were pretreated for 1 h with PKI166 and then stimulated with epidermal growth factor. EGFR-specific tyrosine kinase autophosphorylation measured by Western immunoblotting was inhibited by PKI166 in a dose-dependent fashion at all doses tested (0.01-1 micro M). Next, the induction of apoptosis in JMAR cells treated with paclitaxel (0.001 to 0.1 micro M) with or without PKI166 (0, 1, or 2 micro M) was determined using a propidium iodide assay. The addition of 2.0 micro M PKI166 significantly increased tumor cell death, shifting the amount of paclitaxel needed to induce apoptosis in 50% of cells from 0.1 to 0.001 micro M. These in vitro findings were confirmed using an orthotopic model of oral cancer. JMAR oral cancer cells were implanted into the tongues of nude mice. After lingual tumors developed, mice were randomized into four groups (n = 10): (a) oral PKI166 (100 mg/kg); (b) i.p. paclitaxel (200 micro g/wk); (c) PKI166 and paclitaxel; or (d) placebo. Mice treated with PKI166/paclitaxel demonstrated a significant increase in survival (P = 0.028). After necropsy, all tongue tumors were evaluated for apoptosis by the terminal deoxynucleotidyl transferase-mediated nick end labeling assay. A greater apoptotic fraction of tumor cells was found in tumors of mice treated with paclitaxel and PKI166 as compared with the other treatment groups (136.4 versus 37.8; P = 0.016). CONCLUSIONS: Combination therapy with paclitaxel and PKI166 prolongs survival in an orthotopic preclinical model of tongue cancer by increasing programmed cell death of oral cancer.