Anchoring of intratumorally administered cytokines to collagen safely potentiates systemic cancer immunotherapy

The clinical application of cytokine therapies for cancer treatment remains limited due to severe adverse reactions and insufficient therapeutic effects. Although cytokine localization by intratumoral administration could address both issues, the rapid escape of soluble cytokines from the tumor invariably subverts this effort. We find that intratumoral administration of a cytokine fused to the collagen-binding protein lumican prolongs local retention and markedly reduces systemic exposure. Combining local administration of lumican-cytokine fusions with systemic immunotherapies (tumor-targeting antibody, checkpoint blockade, cancer vaccine, or T cell therapy) improves efficacy without exacerbating toxicity in syngeneic tumor models and the Braf^V600E /Pten^fl/fl genetically engineered melanoma model. Curative abscopal effects on noncytokine-injected tumors were also observed as a result of a protective and systemic CD8⁺ T cell response primed by local therapy. Cytokine collagen-anchoring constitutes a facile, tumor-agnostic strategy to safely potentiate otherwise marginally effective systemic immunotherapies.

Maximizing response to intratumoral immunotherapy in mice by tuning local retention

Direct injection of therapies into tumors has emerged as an administration route capable of achieving high local drug exposure and strong anti-tumor response. A diverse array of immune agonists ranging in size and target are under development as local immunotherapies. However, due to the relatively recent adoption of intratumoral administration, the pharmacokinetics of locally-injected biologics remains poorly defined, limiting rational design of tumor-localized immunotherapies. Here we define a pharmacokinetic framework for biologics injected intratumorally that can predict tumor exposure and effectiveness. We find empirically and computationally that extending the tumor exposure of locally-injected interleukin-2 by increasing molecular size and/or improving matrix-targeting affinity improves therapeutic efficacy in mice. By tracking the distribution of intratumorally-injected proteins using positron emission tomography, we observe size-dependent enhancement in tumor exposure occurs by slowing the rate of diffusive escape from the tumor and by increasing partitioning to an apparent viscous region of the tumor. In elucidating how molecular weight and matrix binding interplay to determine tumor exposure, our model can aid in the design of intratumoral therapies to exert maximal therapeutic effect.

New concepts on formation of Brunn's nests and cysts in urinary tract mucosa

To the present time, Brunn's nests have been conceived as being the result of pinching off of epithelial nests from urothelial buds. Mucosal cysts were considered to originate from Brunn's nests. In the present study, it was observed that under the influence of a strong stimulus of repair, the urothelial cells in the proximity of the focus of repair undergo numerous mitoses. The underlying connective tissue becomes loose, isolated cells of the lining urothelium "drop off" into the lamina propria in which they migrate as in a culture medium. There they multiply and form nests of cells at a distance from the lining urothelium. These migrating cells frequently have an early tendency to become arranged into cysts. Thus, during this process of repair urothelial cells behave temporarily as malignant cells.

CaATP as a substrate to investigate the myosin lever arm hypothesis of force generation

In an effort to test the lever arm model of force generation, the effects of replacing magnesium with calcium as the ATP-chelated divalent cation were determined for several myosin and actomyosin reactions. The isometric force produced by glycerinated muscle fibers when CaATP is the substrate is 20% of the value obtained with MgATP. For myosin subfragment 1 (S1), the degree of lever arm rotation, determined using transient electric birefringence to measure rates of rotational Brownian motion in solution, is not significantly changed when calcium replaces magnesium in an S1-ADP-vanadate complex. Actin activates S1 CaATPase activity, although less than it does MgATPase activity. The increase in actin affinity when S1. CaADP. P(i) is converted to S1. CaADP is somewhat greater than it is for the magnesium case. The ionic strength dependence of actin binding indicates that the change in apparent electrostatic charge at the acto-S1 interface for the S1. CaADP. P(i) to S1. CaADP step is similar to the change when magnesium is bound. In general, CaATP is an inferior substrate compared to MgATP, but all the data are consistent with force production by a lever arm mechanism for both substrates. Possible reasons for the reduced magnitude of force when CaATP is the substrate are discussed.

Cryosurgery as a treatment for prostate carcinoma: results and complications

BACKGROUND

There has been a resurgence of interest in cryosurgical ablation of the prostate for the treatment of carcinoma. This is due to recent advances in cryosurgical technology, which have resulted in relatively lower morbidity. The objective of this study was to evaluate the effectiveness of ultrasound-guided cryosurgical ablation of prostate carcinoma.

METHODS

Eighty-three patients who had biopsy-proven prostate carcinoma underwent cryosurgical ablation of their entire prostate gland. The initial group of 12 patients had their procedures performed under ultrasound guidance only. The other 71 patients had cryosurgery performed with temperature monitoring in combination with ultrasound guidance. Twelve patients who had positive biopsies underwent a second cryosurgical procedure. All patients had prostate specific antigen (PSA) levels measured at 3, 6, 12, 18, 24, and 30 months after cryosurgery. Ultrasound-guided sextant biopsies were performed at 3-6, 12-18, and 24 months.

RESULTS

The median PSA dropped by 95%, from a preoperative value of 4.3 ng/mL to 0.2 ng/mL 30 months after cryosurgery. The authors experienced a high failure rate (positive biopsies) of 83% for the initial group of 12 patients who did not have temperature monitoring during the cryosurgical procedure. This was in contrast to a success rate of 90% (negative biopsies) for the next 71 patients, who did have temperature monitoring (P < 0.05, chi-square test). Twelve patients underwent a second cryosurgery, and the success rate for this group was 91% (11 of 12 patients). The combined success rate for both the first cryosurgery and the second was 94% (62 of 77 patients). Complications included urethral sloughing, urinary incontinence, impotence, bladder neck contracture, and bladder contracture. The majority of patients recovered rapidly from their cryosurgical procedures and were able to resume normal activities 3-4 weeks afterward.

CONCLUSIONS

These preliminary results demonstrate that cryosurgical ablation of the prostate is a viable treatment option for prostate carcinoma. In the authors' experience, ultrasound alone may not be adequate for monitoring the entire cryosurgical procedure. The authors found that temperature monitoring shortened their learning curve, enabled them to freeze prostate tissue more aggressively, and may have contributed to their overall success.