Reproducibility of vaginal immobilization balloons in situ overnight for cervical cancer brachytherapy.

PURPOSE: The use of vaginal immobilization balloons placed into the vagina for immobilization of tandem and ovoid (T+O) applicator during high-dose-rate (HDR) brachytherapy delivery has been used at our institution, and seems to have improved our patient comfort, decreased procedure time, and minimized applicator misplacement. We aimed to show that these balloons, while originally marketed for single-day use, are safe and maintain applicator positioning/dosimetry when left in situ overnight for treatment delivery on sequential days. MATERIAL AND METHODS: Forty-two paired computed tomography (CT) scans from thirteen patients who underwent T+O HDR treatments on sequential days with vaginal immobilization balloons in situ overnight were retrospectively compared to calculate mean change of balloon volumes and balloon/T+O distance to bony landmarks. Dosimetric planning was retroactively performed on day 2 using CT scan of each pair, and the change in estimated radiation delivery to the bladder and rectum was compared. RESULTS: No statistically significant overnight changes were found in balloon volumes or anterior balloon positioning. The posterior balloon shifted -0.29 ±0.46 cm (p = 0.03) to the anterior public symphysis and 0.32 ±0.50 cm (p = 0.01) to the right femoral head. The tandem shifted 0.37 ±0.39 cm (p = 0.002) to the pubic symphysis. There was no significant difference found in radiation delivered to the bladder or rectum between the paired scans. CONCLUSIONS: This study showed minimal change in balloon volumes, balloons/T+O positioning, or in radiation dose to bladder and rectum when the applicator remained overnight. These findings support that inflatable vaginal immobilization balloons remaining in situ overnight for additional HDR T+O treatments on sequential days, is safe and provides stable dosimetry.

Preliminary Clinical Evaluation of Intrafraction Prostate Displacements for Two Immobilization Systems.

Immobilization systems and their corresponding set-up errors influence the clinical target volume to the planning target volume (CTV-PTV) margins, which is critical for hypofractionated prostate stereotactic body radiotherapy (SBRT). This preliminary study evaluates intrafraction prostate displacement for two immobilization systems (A and B). Six consecutive patients having localized prostate cancer and implanted prostate marker seeds were studied. Planar X-ray images were acquired pre- and post-treatment to find the intrafraction prostate displacement. The average absolute displacements (lateral, longitudinal, vertical) were 0.9 ± 0.4 mm, 1.7 ± 0.1 mm, 1.3 ± 0.3 mm (system A), and 0.5 ± 0.2 mm, 0.6 ± 0.1 mm, 0.8 ± 0.3 mm (system B), with average three-dimensional displacements of 2.6 ± 0.2 mm (system A) and 1.3 ± 0.2 mm (system B). The computed CTV-PTV margins (lateral, longitudinal, vertical) were 2.5 mm, 2.5 mm, 3.6 mm and 1.4 mm, 1.6 mm, 2.4 mm for systems A and B, respectively. This suggests that the immobilization system influences intrafraction prostate displacement and, therefore, the margins applied. However, the margins found for both systems are comparable to the margins used for hypofractionated prostate SBRT.

Prospective Study of Use of Edmonton Symptom Assessment Scale Versus Routine Symptom Management During Weekly Radiation Treatment Visits.

PURPOSE: During radiotherapy (RT), patient symptoms are evaluated and managed weekly during physician on-treatment visits (OTVs). The Edmonton Symptom Assessment Scale (ESAS) is a 9-symptom validated self-assessment tool for reporting common symptoms in patients with cancer. We hypothesized that implementation and physician review of ESAS during weekly OTVs may result in betterment of symptom severity during RT for certain modifiable domains. METHODS: As an institutional quality improvement project, patients were partitioned into 2 groups: (1) 85 patients completing weekly ESAS (preintervention) but blinded to their providers who gave routine symptom management and (2) 170 completing weekly ESAS (postintervention group) reviewed by providers during weekly OTVs with possible intervention. To determine the independent association with symptom severity of the intervention, multivariate logistic regression was performed. At study conclusion, provider assessments of ESAS utility were also collected. RESULTS: Compared with the preintervention group, stable or improved symptom severity was seen in the postintervention group for pain (70.7% v 85.6%; P = .005) and anxiety (79.3% v 92.9%; P = .002). The postintervention group had decreased association (on multivariate analysis) with worsening severity of pain (OR, 0.13; P < .001), nausea (OR, 0.25; P = .023), loss of appetite (OR, 0.30; P = .024), and anxiety (OR, 0.19; P = .005). Most physicians (87.5%) and nurses (75%) found ESAS review useful in symptom management. CONCLUSION: Incorporation of ESAS for OTVs was associated with stable or improved symptom severity where therapeutic intervention is more readily available, such as counseling, pain medication, anti-emetics, appetite stimulants, and anti-anxiolytics. The incorporation of validated patient-reported symptom-scoring tools may improve provider management.

Comprehensive Lifestyle Improvement Program for Prostate Cancer (CLIPP): Protocol for a Feasibility and Exploratory Efficacy Study in Men on Androgen Deprivation Therapy.

BACKGROUND: Androgen deprivation therapy (ADT) for prostate cancer is associated with adverse cardiometabolic effects such as reduced libido, hot flashes, metabolic syndrome, diabetes, myocardial infarction, and stroke. This reduces quality of life and potentially increases mortality. Several large clinical trials have demonstrated improvements in cardiometabolic risk with comprehensive multimodality lifestyle modification. However, there is a lack of data for such interventions in men on ADT for prostate cancer, and existing studies have used non-standardized interventions or lacked data on metabolic risk factors. OBJECTIVE: The Comprehensive Lifestyle Improvement Project for Prostate Cancer (CLIPP) is designed to address these gaps by using an intervention modeled on the Diabetes Prevention Program, a standardized multicomponent intervention with demonstrated effectiveness in reducing cardiometabolic risk factors that has been successfully adapted for multiple disease types including breast cancer. METHODS: A single-arm unblinded clinical trial will be conducted to determine the feasibility of conducting a 24-week comprehensive lifestyle modification intervention that targets weight loss and increased physical activity modeled on the Diabetes Prevention Program in 30 men on ADT for prostate cancer. Secondary aims are to determine the effect of the intervention on cardiometabolic markers and quality of life. The tertiary aim is to determine the effect of the intervention on markers of inflammation and angiogenesis, important mechanisms for prostate cancer progression. Participants will be recruited from the University of Arizona Cancer Center and the surrounding community. The intervention will be delivered weekly in person and over the phone for 16 weeks. For Weeks 16-24, participants receive weekly phone calls from the study health coach to motivate them to continue their lifestyle modification. Questionnaire and biological data are collected at baseline, 12 weeks, and 24 weeks. Body composition using dual-energy x-ray absorptiometry scans will be performed at baseline and end of study. RESULTS: Based on a sample size of 30, the two-sided 95% confidence interval will not be wider than 0.373 standard deviations for the adherence rate and will not be wider than 0.374 for the retention rate. In addition, the study will have a power of 80% to detect a change of 0.47 standard deviations from baseline for each of the markers investigated in the secondary and tertiary aims assuming a within-subject correlation of 0.20 at a significance level of 5%. The recruitment period is from October 2018 to April 2019. CONCLUSIONS: The aim of CLIPP is to determine the feasibility of conducting a Diabetes Prevention Program-style comprehensive lifestyle modification intervention in men with ADT for prostate cancer and its effects on cardiometabolic adverse effects, quality of life, as well as markers of inflammation and angiogenesis. Results will inform the development of future clinical trials in this population. INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID): DERR1-10.2196/12579.

alpha6 integrin cleavage: sensitizing human prostate cancer to ionizing radiation.

PURPOSE: The goal was to determine if prostate tumor cells containing a mutant alpha6 integrin would be defective in tumor re-population following clinically relevant fractionated ionizing radiation (IR) treatments. MATERIAL AND METHODS: Human prostate cancer cells derived from PC3N cells were used which conditionally expressed a cleavable, wild type form of alpha6 integrin (PC3N-alpha6-WT) or a mutated non-cleavable form of alpha6 integrin (PC3N-alpha6-RR). The resulting tumor growth before, during and after fractionated doses of IR (3 Gyx10 days) was analyzed using the endpoints of tumor growth inhibition (T/C), tumor growth delay (T-C), tumor doubling time (Td) and tumor cell kill (Log(10) cell kill). RESULTS: The T/C values were 36.1% and 39.5%, the T-C values were 20.5 days and 28.5 days and the Td values were 5.5 and 10.5 days for the irradiated PC3N-alpha6-WT and PC3N-alpha6-RR cells, respectively. The Log(10) was 1.1 for the PC3N-alpha6-WT cells and 0.8 for the PC3N-alpha6-RR cells. The tumor response to IR was altered in tumors expressing the mutant alpha6 integrin as indicated by a significant increase in tumor growth inhibition, an increase in tumor growth delay, an increase in tumor doubling time and an increase in tumor cell kill. CONCLUSIONS: Blocking integrin cleavage in vivo may be efficacious for increasing the IR responsiveness of slow growing, pro-metastatic human prostate cancer.

Molecular mechanisms regulating the tumor-targeting potential of splice-activated gene expression.

Previous studies have suggested that differences in the ability of normal and malignant cells to process certain alternatively spliced pre-mRNA transcripts can be exploited as a potentially powerful means of targeting the expression of therapeutic genes to tumor cells in vivo and in vitro. Specifically, it was shown that efficient processing of minigene constructs containing the alternatively spliced CD44 exons v9 and v10 only occurs in tumor cells that express CD44 isoforms that incorporate these exons (e.g. CD44R1). In the present study, efforts were made to define the molecular mechanisms that underlie the apparent specificity of this process. RT-PCR analysis and DNA sequencing were used to characterize the various splicing events that occur between CD44 exons v8, v9 and v10 following transfection of minigene constructs containing these various exons into CD44R1-positive (PC3) and CD44R1-negative (T24) cell lines. The results obtained confirm that although the v8-v9 intron is efficiently removed in both CD44R1-positive and CD44R1-negative cells, the corresponding v9-v10 intron is accurately spliced and the exons appropriately joined only in lines that express v10-containing CD44 isoforms (e.g. PC3). In CD44R1-negative cell lines (e.g. T24) alternative 5' and 3' splice sites located within the v9-v10 intron are preferentially used, resulting in various portions of the intron being retained within the final processed mRNA product. It is proposed that identification of these functionally important intronic sequence elements will facilitate the development of second generation "splice activated gene expression" vectors that may prove useful in various cancer gene therapy applications.

Alternative splicing as a novel of means of regulating the expression of therapeutic genes.

In order to determine the potential of alternative splicing as a means of targeting the expression of therapeutic genes to tumor cells in vivo, a series of episomal plasmid-based "splice-activated gene expression" (pSAGE) vectors was generated, which contain minigene cassettes composed of various combinations of the three alternatively spliced exons present in the differentially expressed adhesion protein CD44R1 (v8, v9, and v10) with or without their corresponding intronic sequences, positioned in-frame between the CD44 leader sequence and a "leaderless" human liver/bone/kidney alkaline phosphatase (ALP) cDNA. Because both the v8-v9 and v9-v10 introns contain multiple in-frame stop codons, the expression and enzymatic activity of ALP are dependent upon the accurate removal of intronic sequences from the pre-mRNA transcripts encoded by these constructs. The various pSAGE constructs were introduced into CD44H-positive (T24) and CD44R1-positive (PC3) target cells by electroporation and transfectants selected in hygromycin B. ALP expression was determined by staining with the ALP substrate, BCIP/INT, and the transfected cells tested for their sensitivity to the inactive prodrug, etoposide phosphate. ALP-mediated dephosphorylation of etoposide phosphate generates the potent topoisomerase II inhibitor etoposide. The data obtained indicate that whereas the v8-v9 intron is spliced in both CD44H- and CD44R1-positive cells, the v9-v10 intron is efficiently and accurately removed only in CD44R1-positive cells. Furthermore, only CD44R1-positive cells were sensitized to etoposide phosphate when transfected with the v9-v10.ALP construct. These data emphasize the potential usefulness of alternative splicing as a novel means of targeting gene expression to tumor cells in vivo.

Exploiting the differential production of angiogenic factors within the tumor microenvironment in the design of a novel vascular-targeted gene therapy-based approach to the treatment of cancer.

PURPOSE: The aim of this study is to explore a novel strategy through which the differential production of pro-angiogenic cytokines within the tumor microenvironment can be exploited as a means of selectively killing the vascular endothelial cells upon which the survival and growth of a tumor depend. METHODS AND MATERIALS: Adenoviral vectors encoding a chimeric cell surface receptor composed of the extracellular domain of the vascular endothelial growth factor (VEGF) receptor Flk-1/KDR fused in frame to the membrane spanning and cytoplasmic domain of Fas were constructed and used to transduce primary human endothelial cells in vitro. The apoptotic response of these cells induced upon ligation of the chimeric receptor with VEGF was determined by measuring caspase-3 activation, AnnexinV-FITC binding, and the release of glucose-6-phosphate dehydrogenase. RESULTS: The chimeric Flk-1/Fas protein is stable and expressed at high levels on the surface of adenovirally transduced cells. Upon the addition of exogenous VEGF, these cells undergo rapid apoptosis. CONCLUSIONS: Receptor/Fas chimeras that recognize and bind pro-angiogenic cytokines represent a novel means by which the signal transduction events normally triggered in vascular endothelial cells upon the binding of angiogenic cytokines may be redirected toward the induction of apoptotic cell death. It is proposed that these constructs will prove of value in the further development of safe and effective vascular-targeted gene therapy-based approaches to the treatment of cancer.

Vascular-targeted cancer gene therapy.

As a consequence of the dramatic progress that has been made in recent years towards elucidating the diverse molecular events involved in the development and pathogenesis of malignant disease, there is now no shortage of genes that can be exploited or targeted in the context of cancer gene therapy. Many of these have been shown to be effective both in vitro and in various animal models, and a number have progressed to the clinic. The results of these later studies, although generally encouraging, are perhaps less dramatic than one might have hoped. Although a number of factors undoubtedly contribute to this finding, it is evident that a major reason relates to the difficulties implicit in achieving efficient in vivo gene transfer, particularly in a clinical context. Targeting gene therapy, not to the malignant population, but instead to the vasculature upon which the survival and growth of a tumour depends constitutes an alternative approach that overcomes some of the delivery problems associated with established tumour cell-directed strategies.

Identification of sequence motifs responsible for the adhesive interaction between exon v10-containing CD44 isoforms.

Previous studies have demonstrated that CD44 isoforms containing the alternatively spliced exon v10 promote cell-cell adhesion via a mechanism that involves the recognition of chondroitin sulfate side chains presented on the surface of interacting cells in association with other CD44 molecules. Sequence analysis revealed the presence within exon v10 of two motifs that may be relevant to this interaction, a B[X(7)]B motif that may contribute to the recognition and binding of chondroitin sulfate and a serine-glycine motif that may serve as a site of chondroitin sulfate attachment. To determine whether either of these two motifs explain the unique adhesive activity of exon v10-containing CD44 isoforms, each was targeted by site-directed mutagenesis, and the adhesive activity of the resultant mutants was determined using a quantitative cell-cell binding assay. The data obtained demonstrate conclusively that it is the exon v10-encoded B[X(7)]B motif that is solely responsible for the enhanced adhesive activity of exon v10-containing CD44 isoforms.