Suppression and transient induction of lymphokines in cancer patients after administration of polyethylene glycolated interleukin-2

Tumor efficacy and biodistribution of linear polyethylenimine-cholesterol/DNA complexes

Non-viral polymer/pDNA complexes were formed using linear polyethylenimine (LPEI) Mw 25 k conjugated to cholesterol in a T-shaped geometry (LPC-T) and pDNA encoding murine interleukin-12 (pmIL-12e). These complexes were subsequently injected weekly into BALB/c mice intravenously and locally for the treatment of murine renal cell adenocarcinoma (Renca) induced pulmonary metastases and subcutaneous (SC) Renca tumors, respectively. At the cessation of the pulmonary metastases study, the number of pulmonary metastases was significantly less (p < 0.001) with systemic injections of LPC-T/pmIL-12e formulations than with pmIL-12e alone or pmIL-12e complexed with LPEI, branched polyethylenimine (BPEI) Mw 25 k, or an LPEI/pEGFP control. In addition, biodistribution studies showed increased pulmonary levels of both the LPC-T carrier and pmIL-12e vector up to 3 hr after systemic injection of the LPC-T/pmIL-12e complexes into mice carrying pulmonary metastases. Furthermore, mice systemically treated with LPC-T/pmIL-12e showed a near linear profile in weight gain in the course of the pulmonary metastases study that suggests increased biocompatibility. Finally, due to favorable characteristics in vitro, LPC-T was also used for local (peritumoral) injection of SC Renca tumors. Tumor stasis and slight tumor regression were seen only with the LPC-T/pmIL-12e treated mice compared to BPEI/pmIL-12e, LPEI/pmIL-12e, and naked pmIL-12e controls. Thus, it was concluded that LPC-T is an effective carrier for passive targeting of the pulmonary tissue, treatment of Renca-induced pulmonary metastases, and local administration of Renca cell SC tumors.

Pegylated brain-derived neurotrophic factor shows improved distribution into the spinal cord and stimulates locomotor activity and morphological changes after injury

The neurotrophin brain-derived neurotrophic factor (BDNF) shows promise for the treatment of central nervous system (CNS) trauma and disease. Effective delivery methods are required, however, for BDNF to be useful as a therapeutic agent. To this end, we examined the penetration of intrathecally infused N-terminal pegylated BDNF (peg-BDNF) compared to similar infusion of native BDNF after spinal cord injury (SCI). Pegylation dramatically improved delivery of BDNF to the spinal cord and induced the expression of Fos in spinal cord neurons. To test whether enhanced delivery would improve the modest effects on behavioral recovery and axonal outgrowth observed with native BDNF infusion, we assessed the efficacy of 2-week 25 microg/day peg-BDNF treatment, beginning 12-24 h (early) or 15 days (delayed) after midthoracic spinal contusion. Similar to native BDNF, early treatment with peg-BDNF accelerated the recovery of stepping in the open-field and acutely stimulated locomotor central pattern generator activity, as seen by the activation of hindlimb airstepping during either period of administration. The infusion of peg-BDNF, regardless of the timing of delivery, was related to enhanced sprouting of putative cholinergic fibers, like that observed after high dose native BDNF treatment. Despite improved delivery, however, neither axonal responses nor the extent of locomotor recovery were enhanced compared to native BDNF treatment. This suggests that alternative strategies, such as neurotrophin treatment in conjunction with cell transplantation techniques, or treatment nearer the cell bodies of target neurons might be employed in an attempt to effect significant repair after SCI.