Prostate cancer gene therapy and the role of radiation

Photoactivatable Biomedical Materials Based on Luminogens with Aggregation-Induced Emission (AIE) Characteristics

Fluorescence probes with aggregation-induced emission (AIE) property are fascinating and vital in biological fields due to their bright fluorescence in the solid state. In contrast, traditional AIE materials are obscured by the off-target effects and lack of spatial and temporal control. Photoactivatable materials with AIE characteristics, whose physicochemical behaviors can be remotely activated by light, provide great potential in biochemical information acquisition with high spatial and temporal resolution. By using AIE-featured photoactivatable fluorescence probes, accurate analysis of the targets of interest is possible. For example, where, when, and to what extent a process is started or stopped by manipulating the non-invasive light accurately. Thus, many researchers are enthusiastic about developing AIE-featured photoactivatable materials and mainly focus on developing novel molecules by rational molecular structure design, and exploring advanced applications by appropriate molecular functionalization. In this review, the recent achievements of photoactivatable materials with AIE characteristics from the aspects involving inherent mechanism of photoactivity, molecular design strategy, and the corresponding applications in biological fields, are summarized. The biological applications are highlighted and discussed, including photoactivatable bioimaging, diagnosis, and photo-controlled therapy. Finally, the challenges and prospects of the AIE-featured photoactivatable materials are also outlined and discussed.

Structural consequences of Kcna1 gene deletion and transfer in the mouse hippocampus

PURPOSE

Mice lacking the Kv1.1 potassium channel alpha subunit encoded by the Kcna1 gene develop recurrent behavioral seizures early in life. We examined the neuropathological consequences of seizure activity in the Kv1.1(-/-) (knock-out) mouse, and explored the effects of injecting a viral vector carrying the deleted Kcna1 gene into hippocampal neurons.

METHODS

Morphological techniques were used to assess neuropathological patterns in hippocampus of Kv1.1(-/-) animals. Immunohistochemical and biochemical techniques were used to monitor ion channel expression in Kv1.1(-/-) brain. Both wild-type and knockout mice were injected (bilaterally into hippocampus) with an HSV1 amplicon vector that contained the rat Kcna1 subunit gene and/or the E. coli lacZ reporter gene. Vector-injected mice were examined to determine the extent of neuronal infection.

RESULTS

Video/EEG monitoring confirmed interictal abnormalities and seizure occurrence in Kv1.1(-/-) mice. Neuropathological assessment suggested that hippocampal damage (silver stain) and reorganization (Timm stain) occurred only after animals had exhibited severe prolonged seizures (status epilepticus). Ablation of Kcna1 did not result in compensatory changes in expression levels of other related ion channel subunits. Vector injection resulted in infection primarily of granule cells in hippocampus, but the number of infected neurons was quite variable across subjects. Kcna1 immunocytochemistry showed "ectopic" Kv1.1 alpha channel subunit expression.

CONCLUSIONS

Kcna1 deletion in mice results in a seizure disorder that resembles--electrographically and neuropathologically--the patterns seen in rodent models of temporal lobe epilepsy. HSV1 vector-mediated gene transfer into hippocampus yielded variable neuronal infection.

Phase I–II trial evaluating combined intensity-modulated radiotherapy and in situ gene therapy with or without hormonal therapy in treatment of prostate cancer—interim report on PSA response and biopsy data

PURPOSE

There is an evolving role for combining radiotherapy (RT) with gene therapy in the management of prostate cancer. However, the clinical results of this combined approach are much needed. The preliminary results addressing the safety of this Phase I-II study combining RT and gene therapy (adenovirus/herpes simplex virus-thymidine kinase gene/valacyclovir with or without hormonal therapy) in the treatment of prostate cancer have been previously reported. We now report the prostate-specific antigen (PSA) response and biopsy data.

METHODS AND MATERIALS

This trial was composed of three separate arms. Arm A consisted of low-risk patients (Stage T1-T2a, Gleason score <7, pretreatment PSA <10 ng/mL) treated with combined RT-gene therapy. A mean dose of 76 Gy was delivered to the prostate with intensity-modulated RT. They also received adenovirus/herpes simplex virus-thymidine kinase/valacyclovir gene therapy. Arm B consisted of high-risk patients (Stage T2b-T3, Gleason score >6, pretreatment PSA level >10 ng/mL) treated with combined RT-gene therapy and hormonal therapy (luteinizing hormone-releasing hormone agonist [30-mg Lupron, 4-month depot] and an antiandrogen [flutamide, 250 mg t.i.d. for 14 days]). Arm C consisted of patients with Stage D1 (positive pelvic lymph nodes) who received the same regimen as Arm B with the addition of 45 Gy to the pelvic lymphatics. PSA determination and biopsy were performed before, during, and after treatment. The American Society for Therapeutic Radiology and Oncology consensus definition (three consecutive rises in PSA level) was used to denote PSA failure.

RESULTS

Fifty-nine patients (29 in Arm A, 26 in Arm B, and 4 in Arm C) completed the trial. The median age was 68 years (range, 39-85 years). The median follow-up for the entire group was 13.5 months (range, 1.4-27.8 months). Only Arm A patients were observed to have an increase in PSA on Day 14. The PSA then declined appropriately. All patients in Arm A (median follow-up, 13.4 months) and Arm B (median follow-up, 13.9 months) had biochemical control at last follow-up. Three patients in Arm C (with pretreatment PSA of 335, 19.6, and 2.5 ng/mL and a combined Gleason score of 8, 9, and 9 involving all biopsy cores) had biochemical failure at 3, 3, and 7.7 months. Two patients had distant failure in bone and 1 patient in the para-aortic lymph nodes outside the RT portal. Six to twelve prostate biopsies performed in these 3 patients revealed no evidence of residual carcinoma. In Arm A, biopsy showed no evidence of carcinoma in 66.7% (18 of 27), 92.3% (24 of 26), 91.7% (11 of 12), 100% (8 of 8), and 100% (6 of 6) at 6 weeks, 4 months, 12 months, 18 months, and 24 months after treatment, respectively. In Arm B, no evidence of carcinoma on biopsy was noted in 96% (24 of 25), 90.5% (19 of 21), 100% (14 of 14), 100% (7 of 7), and 100% (2 of 2), respectively, in the same interval after treatment.

CONCLUSION

This is the first reported trial of its kind in the field of prostate cancer that aims to expand the therapeutic index of RT by combining it with in situ gene therapy. The initial transient PSA rise in the Arm A patients may have been a result of local immunologic response or inflammation elicited by in situ gene therapy. Additional investigation to elucidate the mechanisms is needed. Hormonal therapy may have obliterated this rise in Arm B and C patients. The biopsy data were encouraging and appeared to show no evidence of malignancy earlier than historical data. Combined RT, short-course hormonal therapy, and in situ therapy appeared to provide good locoregional control but inadequate systemic control in patients with positive pelvic lymph nodes. Longer term use of hormonal therapy in addition to gene therapy and RT has been adopted for this group of patients to maximize both locoregional and systemic control.