Gramicidin, a Bactericidal Antibiotic, Is an Antiproliferative Agent for Ovarian Cancer Cells.

Background and Objectives: Gramicidin, a bactericidal antibiotic used in dermatology and ophthalmology, has recently garnered attention for its inhibitory actions against cancer cell growth. However, the effects of gramicidin on ovarian cancer cells and the underlying mechanisms are still poorly understood. We aimed to elucidate the anticancer efficacy of gramicidin against ovarian cancer cells. Materials and Methods: The anticancer effect of gramicidin was investigated through an in vitro experiment. We analyzed cell proliferation, DNA fragmentation, cell cycle arrest and apoptosis in ovarian cancer cells using WST-1 assay, terminal deoxynucleotidyl transferase dUTP nick and labeling (TUNEL), DNA agarose gel electrophoresis, flow cytometry and western blot. Results: Gramicidin treatment induces dose- and time-dependent decreases in OVCAR8, SKOV3, and A2780 ovarian cancer cell proliferation. TUNEL assay and DNA agarose gel electrophoresis showed that gramicidin caused DNA fragmentation in ovarian cancer cells. Flow cytometry demonstrated that gramicidin induced cell cycle arrest. Furthermore, we confirmed via Western blot that gramicidin triggered apoptosis in ovarian cancer cells. Conclusions: Our results strongly suggest that gramicidin exerts its inhibitory effect on cancer cell growth by triggering apoptosis. Conclusively, this study provides new insights into the previously unexplored anticancer properties of gramicidin against ovarian cancer cells.

Catecholamines Promote Ovarian Cancer Progression through Secretion of CXC-Chemokines.

Considerable evidence has accumulated in the last decade supporting the notion that chronic stress is closely related to the growth, metastasis, and angiogenesis of ovarian cancer. In this study, we analyzed the conditioned media in SKOV3 ovarian cancer cell lines treated with catecholamines to identify secreted proteins responding to chronic stress. Here, we observed that epinephrine and norepinephrine enhanced the secretion and mRNA expression of CXC-chemokines (CXCL1, 2, 3, and 8). Neutralizing antibodies to CXCL8 and CXCL8 receptor (CXCR2) inhibitors significantly reduced catecholamine-mediated invasion of SKOV3 cells. Finally, we found that the concentration of CXCL1 and CXCL8 in the plasma of ovarian cancer patients increased with stage progression. Taken together, these findings suggest that stress-related catecholamines may influence ovarian cancer progression through the secretion of CXC-chemokines.

Gentian Violet Inhibits Cell Proliferation through Induction of Apoptosis in Ovarian Cancer Cells.

Gentian violet (GV) is known to have antibacterial and antifungal effects, but recent studies have demonstrated its inhibitory effects on the growth of several types of cancer cells. Here, we investigated the anticancer efficacy of GV in ovarian cancer cells. GV significantly reduced the proliferation of OVCAR8, SKOV3, and A2780 cells. Results of transferase dUTP nick and labeling (TUNEL) assay and Western blot assay indicated that the inhibitory effect of GV on ovarian cancer cells was due to the induction of apoptosis. Moreover, GV significantly increased reactive oxygen species (ROS) and upregulated the expression of p53, PUMA, BAX, and p21, critical components for apoptosis induction, in ovarian cancer cells. Our results suggest that GV is a novel antiproliferative agent and is worthy of exploration as a potential therapeutic agent for ovarian cancer.

Complexation of drug and hapten-conjugated aptamer with universal hapten antibody for pancreatic cancer treatment.

Owing to a lack of reliable markers and therapeutic targets, pancreatic ductal adenocarcinoma (PDAC) remains the most lethal malignant tumor despite numerous therapeutic advances. In this study, we utilized cell-SELEX to isolate a DNA aptamer recognizing the natural conformation of the target on the cell surface. PAp7T8, an aptamer optimized by size and chemical modification, exhibited specific targeting to pancreatic cancer cells and orthotopic xenograft pancreatic tumors. To confer therapeutic functions to the aptamer, we adopted a drug-conjugated oligobody (DOligobody) strategy. Monomethyl auristatin E was used as a cytotoxic drug, digoxigenin acted as a hapten, and the humanized anti-digoxigenin antibody served as a universal carrier of the aptamer. The resulting PAp7T8-DOligobody showed extended in vivo half-life and markedly inhibited tumor growth in an orthotopic pancreatic cancer xenograft model without causing significant toxicity. Therefore, PAp7T8-DOligobody represents a promising novel therapeutic delivery platform for PDAC.

Therapeutic Application of Drug-Conjugated HER2 Oligobody (HER2-DOligobody).

Antibody drug conjugates (ADCs), consisting of a cancer-specific antibody and cytotoxic payload, are shown to be a potent class of anticancer therapeutics, with enhanced therapeutic efficacy and reduced "off-target" side effects. However, the therapeutic window of ADCs is narrowed by problems such as difficulty in site-specific conjugation of payload, changes in antibody stability due to payload conjugation, and difficulty in tissue penetration. In this respect, aptamers have advantages in drug-delivery, as they can be easily and stably conjugated with cytotoxic drugs. We previously reported that oligobody, an aptamer-antibody complex, is a novel delivery method for aptamer-based therapeutics. In the current study, we describe DOligobody, a drug-conjugated oligobody comprising an aptamer-drug conjugate and an antibody. A cotinine-conjugated anti-HER2 aptamer (cot-HER2apt) was specifically bound to HER2-positive NCI-N87 cells, and underwent receptor-mediated endocytosis. Further, HER2-DOligobody, a cot-HER2apt-conjugated monomethyl auristatin E (cot-HER2apt-MMAE) oligobody, inhibited the growth of HER2-positive NCI-N87 cells. Finally, systemic administration of HER2-DOligobody significantly reduced tumor growth in a xenograft mouse model. Taken together, these results suggest that our DOligobody strategy may be a powerful platform for rapid, low-cost and effective cancer therapy.