Theranostics, the fusion of therapy and diagnostics for optimizing efficacy and safety of therapeutic regimes, is a growing field that is paving the way towards the goal of personalized medicine for the benefit of patients. The use of light as a remote-activation mechanism for drug delivery has received increased attention due to its advantages in highly specific spatial and temporal control of compound release. Photo-triggered theranostic constructs could facilitate an entirely new category of clinical solutions which permit early recognition of the disease by enhancing contrast in various imaging modalities followed by the tailored guidance of therapy. Finally, such theranostic agents could aid imaging modalities in monitoring response to therapy. This article reviews recent developments in the use of light-triggered theranostic agents for simultaneous imaging and photoactivation of therapeutic agents. Specifically, we discuss recent developments in the use of theranostic agents for photodynamic-, photothermal-or photo-triggered chemo-therapy for several diseases.

Cordycepin (39 deoxyadenosine) has long been used in the study of in vitro assembled polyadenylation complexes, because it terminates the poly(A) tail and arrests the cleavage complex. It is derived from caterpillar fungi, which are highly prized in Chinese traditional medicine. Here we show that cordycepin specifically inhibits the induction of inflammatory mRNAs by cytokines in human airway smooth muscle cells without affecting the expression of control mRNAs. Cordycepin treatment results in shorter poly(A) tails, and a reduction in the efficiency of mRNA cleavage and transcription termination is observed, indicating that the effects of cordycepin on 39 processing in cells are similar to those described in in vitro reactions. For the CCL2 and CXCL1 mRNAs, the effects of cordycepin are post-transcriptional, with the mRNA disappearing during or immediately after nuclear export. In contrast, although the recruitment of RNA polymerase II to the IL8 promoter is also unaffected, the levels of nascent transcript are reduced, indicating a defect in transcription elongation. We show that a reporter construct with 39 sequences from a histone gene is unaffected by cordycepin, while CXCL1 sequences confer cordycepin sensitivity to the reporter, demonstrating that polyadenylation is indeed required for the effect of cordycepin on gene expression. In addition, treatment with another polyadenyation inhibitor and knockdown of poly(A) polymerase a also specifically reduced the induction of inflammatory mRNAs. These data demonstrate that there are differences in the 39 processing of inflammatory and housekeeping genes and identify polyadenylation as a novel target for anti-inflammatory drugs.

5-aminolevulanic acid (ALA), belonging among the promising second generation of sensitizers, was evaluated as an inducer of photodamage on HeLa (human cervical adenocarcinoma) cell line. A diode laser (635 nm) was used as a source for initiation of the photodynamic effect. We studied the influence of different incubation times, various concentrations of sensitizer, different irradiation doses and various combinations of sensitizer and light doses on the photodamage of HeLa cells. Viability of cells was determined by means of neutral red assay. The quantitative cellular uptake of ALA sensitizer was done by spectrophotometric measurements. No prominent cytotoxic or phototoxic effects on HeLa were observed due to sensitizer or light doses when studied independently of each other. However phototoxicity evoked by laser irradiated sensitizer was detected in HeLa cell line.