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Conventional cancer therapies possess a plethora of limitations which led to the awakening of nanotechnology and nanomedicine. However, technological success is widely dependent on complete understanding of the complexity and heterogeneity of tumor biology on one hand and nanobiointeractions associated with challenges of synthesis, translation, and commercialization on the other. The present study therefore deals with one such targeted approach aiming at synthesizing, characterizing, and understanding the efficacy of molybdenum oxide nanoparticles. The phase structure, morphology, and elemental composition of the synthesized nanoparticles were characterized using Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy. The cytotoxicity studies revealed that the IC 50 vales of molybdenum trioxide (MoO 3) particles against skin cancer cells (melanoma and nonmelanoma) were around 200-300 μg. The nanoparticles were found to induce mitochondrial-mediated apoptosis driven by the apoptotic genes such as BAX and Bcl 2. Molybdenum being a cofactor for the majority of metabolic enzymes could have triggered the selective internalization of the nanoparticles which in turn could have modified the granularity of the cytoplasm and subsequently lead to mitochondrial-mediated apoptosis. Further, the anti-angiogenic property of MoO 3 nanoparticles was corroborated using Chick chorioallantoic membrane (CAM) assay and aortic ring assay. Taken together , unraveling the role of MoO 3 nanoparticles in cancer and angiogenesis opens up venues for nano biological intervention of selective cancer cell targeting with minimal damage to the normal cells using natural trace elements that are generally known to influence various metabolic enzymes.

Using a minimalist approach, an 11-residue peptide (Peptide 1) tagged with rhodamine fluorophore was designed and synthesized for selective detection of cancer cells. Peptide 1 contains RGD and NGR motifs to bind, respectively, integrins and aminopeptidase CD13, which are over expressed in cancer cells. Surface tension measurements revealed that peptide 1 possess surface-active property owing to the overall hydrophobicity and cationic nature of the peptide. Peptide 1 displays cancer cell-selective binding at ≤5.0 µM concentrations, while peptide 2 (randomized sequence of 1) shows non-selective binding to normal and cancer cells. Fluorescence microscopy and FACS analysis demonstrated the intracellular localization of peptide 1 in three different cancer cell lines, confirming the role of RGD and NGR motifs.Cytotoxicity assay exhibited the viability of normal and cancer cells up to 100 µM concentrations of peptide 1. Steady-state fluorescence measurements disclosed the preferential interactions of the peptide 1 with anionic POPC/POPG bilayers rather than with zwitterionic POPC lipid bilayers. Circular dichroism studies showed minimal changes in the secondary structure of peptide 1 upon binding with the anionic lipid bilayers. Peptide 1 is largely unordered, non-toxic, and useful for identification of cancer cells. Peptide 1 provides a template for designing drug-loaded peptides for targeted delivery into cancer cells. K E Y W O R D Scell-selective binding, fluorescence, peptide synthesis, peptide-membrane interactions, surface activity, targeting cancer cells | 611 RAJAVENKATESH et al.