A diagnosis of prostate cancer and pursuit of active surveillance is not followed by weight loss: potential for a teachable moment

BACKGROUND

Obesity is a risk factor for incident prostate cancer (PC) as well as risk of disease progression and mortality. We hypothesized that men diagnosed with lower-risk PC and who elected active surveillance (AS) for their cancer management would likely initiate lifestyle changes that lead to weight loss.

METHODS

Patients were enrolled in the Prostate Active Surveillance Study (PASS), a multicenter prospective biomarker discovery and validation study of men who have chosen AS for their PC. Data from 442 men diagnosed with PC within 1 year of study entry who completed a standard of care 12-month follow-up visit were analyzed. We examined the change in weight and body mass index (BMI) over the first year of study participation.

RESULTS

After 1 year on AS, 7.5% (33/442) of patients had lost 5% or more of their on-study weight. The proportion of men who lost 5% or more weight was similar across categories of baseline BMI: normal/underweight (8%), overweight (6%) and obese (10%, χ² test P=0.44). The results were similar for patients enrolled in the study 1 year or 6 months after diagnosis. By contrast, after 1 year, 7.7% (34/442) of patients had gained >5% of their weight.

CONCLUSIONS

Only 7.5% of men with low-risk PC enrolled in AS lost a modest (⩾5%) amount of weight after diagnosis. Given that obesity is related to PC progression and mortality, targeted lifestyle interventions may be effective at this 'teachable moment', as men begin AS for low-risk PC.

Prognostic value of Ki67 in localized prostate carcinoma: a multi-institutional study of >1000 prostatectomies

BACKGROUND

Expanding interest in and use of active surveillance for early state prostate cancer (PC) has increased need for prognostic biomarkers. Using a multi-institutional tissue microarray resource including over 1000 radical prostatectomy samples, we sought to correlate Ki67 expression captured by an automated image analysis system with clinicopathological features and validate its utility as a clinical grade test in predicting cancer-specific outcomes.

METHODS

After immunostaining, the Ki67 proliferation index (PI) of tumor areas of each core (three cancer cores/case) was analyzed using a nuclear quantification algorithm (Aperio). We assessed whether Ki67 PI was associated with clinicopathological factors and recurrence-free survival (RFS) including biochemical recurrence, metastasis or PC death (7-year median follow-up).

RESULTS

In 1004 PCs (∼4000 tissue cores) Ki67 PI showed significantly higher inter-tumor (0.68) than intra-tumor variation (0.39). Ki67 PI was associated with stage (P<0.0001), seminal vesicle invasion (SVI, P=0.02), extracapsular extension (ECE, P<0.0001) and Gleason score (GS, P<0.0001). Ki67 PI as a continuous variable significantly correlated with recurrence-free, overall and disease-specific survival by multivariable Cox proportional hazard model (hazards ratio (HR)=1.04-1.1, P=0.02-0.0008). High Ki67 score (defined as ⩾5%) was significantly associated with worse RFS (HR=1.47, P=0.0007) and worse overall survival (HR=2.03, P=0.03).

CONCLUSIONS

In localized PC treated by radical prostatectomy, higher Ki67 PI assessed using a clinical grade automated algorithm is strongly associated with a higher GS, stage, SVI and ECE and greater probability of recurrence.

Caveolin-1 and a 29-kDa caveolin-associated protein are phosphorylated on tyrosine in cells expressing a temperature-sensitive v-Abl kinase

Caveolin-1 was originally identified as a tyrosine-phosphorylated protein in v-Src-transformed cells and it was suggested that phosphorylation of this protein could mediate transformation by the tyrosine kinase class of oncogenes (J. R. Glenney, 1989, J. Biol. Chem. 264, 20163--20166). We found that caveolin-1 is also phosphorylated on tyrosine in v-Abl-transformed cells. In fact, caveolin-1 and a caveolin-associated protein of 29 kDa are among the strongest phosphotyrosine signals detected in the Abl-expressing cells. In addition, v-Abl shows a preferential phosphorylation of caveolin-1 and the 29-kDa caveolin-associated protein over other proteins in the caveolin-enriched Triton-resistant cell fraction. These data indicate that caveolin-1 and the 29-kDa caveolin-associated protein may be preferred substrates of the Abl kinase. Caveolin-1 is phosphorylated at tyrosine 14 in v-Abl-expressing cells as has been observed previously in v-Src-expressing cells. However, using a temperature-sensitive allele of v-Abl (ts120 v-Abl) we provide evidence that caveolin-1 phosphorylation is not sufficient to mediate the loss of caveolin expression or loss of cell adhesion induced by v-Abl.

Directed hydroxyl radical probing of 16S rRNA in the ribosome: spatial proximity of RNA elements of the 3' and 5' domains

We have shown previously that directed hydroxyl radical probing of 16S rRNA from Fe(II) tethered to specific sites within the RNA gives valuable information about RNA-RNA proximities in 70S ribosomes. Here, we extend that study and present probing data from nt 424 in 16S rRNA. To tether an Fe(II) to position 424 in the rRNA we created a specific discontinuity in the RNA by in vitro transcription of the RNA as two separate fragments corresponding to nt 1-423 and 424-1542. An Fe(II)-BABE was covalently attached to a 5'-guanosine-alpha-phosphorothioate at position 424 and 30S subunits were reconstituted from the two pieces of rRNA and the small subunit proteins. Reconstituted 30S subunits capable of associating with 50S subunits were selected by isolation of 70S ribosomes. Hydroxyl radicals, generated in situ from the tethered Fe(II), cleaved positions in the RNA backbone that were close in three-dimensional space to the Fe(II), and the sites of cleavage were identified using primer extension. Fe(II) tethered to position 424 induces cleavage around nt 424, 513, and 531 in the 5'-domain of 16S rRNA and around nt 1008, 1029, 1044, and 1208 in the 3'-domain of 16S ribosomal RNA. These data constrain the positions of the 420, 1015, 1030 and 1000/1040 helices, for which there is little structural information. Since the 5'- and 3'-domains of 16S rRNA constitute the body and head, respectively, of 30S subunits, these findings provide direct evidence for proximity of RNA elements in the body and head of 30S.

Directed hydroxyl radical probing of 16S ribosomal RNA in 70S ribosomes from internal positions of the RNA

Directed hydroxyl radical probing of 16S ribosomal RNA from Fe(II) tethered to specific sites within the RNA was used to determine RNA-RNA proximities in 70S ribosomes. We have transcribed 16S ribosomal RNA in vitro as two separate fragments, covalently attached an Fe(II) probe to a 5'-guanosine-alpha-phosphorothioate at the junction between the two fragments, and reconstituted 30S subunits with the two separate pieces of RNA and the small subunit proteins. Reconstituted 30S subunits capable of association with 50S subunits were selected by isolation of 70S ribosomes. Hydroxyl radicals, generated in situ from the tethered Fe(II), cleaved sites in the 16S rRNA backbone that were close in three-dimensional space to the Fe(II), and a primer extension was used to identify these sites of cleavage. Two sets of 16S ribosomal RNA fragments, 1-360/361-1542 and 1-448/449-1542, were reconstituted into active 30S subunits. Fe(II) tethered to position 361 results in cleavage of 16S rRNA around nucleotides 34, 160, 497, 512, 520, 537, 552, and 615, as well as around positions 1410, 1422, 1480, and 1490. Fe(II) tethered to position 449 induces cleavage around nucleotide 488 and around positions 42 and 617. Fe(II) tethered to the 5' end of 16S rRNA induces cleavage of the rRNA around nucleotides 5, 601, 615, and 642. These results provide constraints for the positioning of these regions of 16S rRNA, for which there has previously been only limited structural information, within the 30S subunit.

Synthesis, structure-activity relationships, and pharmacological evaluation of a series of fluorinated 3-benzyl-5-indolecarboxamides: identification of 4-[[5-[((2R)-2-methyl-4,4,4-trifluorobutyl)carbamoyl]-1-methyl indol- 3-yl]methyl]-3-methoxy-N-[(2-methylphenyl)sulfonyl]benzamide, a potent, orally active antagonist of leukotrienes D4 and E4

The continued exploration of a series of 3-(arylmethyl)-1H-indole-5-carboxamides by the introduction of fluorinated amide substituents has resulted in the discovery of 4-[[5-[((2R)-2-methyl-4,4,4-trifluorobutyl)carbamoyl]-1-methyli ndol- 3-yl]methyl]-3-methoxy-N-[(2-methyl-phenyl)sulfonyl]benzamide (38p, ZENECA ZD3523), which has been chosen for clinical evaluation. This compound exhibited a Ki of 0.42 nM for displacement of [3H]LTD4 on guinea pig lung membranes, a pKB of 10.13 +/- 0.14 versus LTE4 on guinea pig trachea, and an oral ED50 of 1.14 mumol/kg opposite LTD4-induced bronchoconstriction in guinea pigs. The R enantiomer was found to be modestly more potent than the S enantiomer 38o. Modification of the amide substituent to afford achiral compounds was unsuccessful in achieving comparable levels of activity. Profiling of 38p opposite a variety of functional assays has demonstrated the selectivity of this compound as a leukotriene receptor antagonist. The enantioselective synthesis of 38p, which employed a diastereoselective alkylation of (4R,5S)-3-(1-oxo-4,4,4-trifluorobutyl)-4-methyl-5-phenyl-2-oxazoli dinone (27) as the key step to establish the chirality of the amide substituent, provided an efficient route for generating 38p in > 99% enantiomeric purity.