Pegfilgrastim Biosimilars in US Supportive Oncology: A Narrative Review of Administration Options and Economic Considerations to Maximize Patient Benefit.

Granulocyte colony-stimulating factor (G-CSF) biologics, such as pegfilgrastim, are a standard of care in supportive cancer treatment that are administered once per chemotherapy cycle to reduce the incidence of febrile neutropenia. The high cost of these biologics in the United States can be a limiting factor to accessing care; however, lower-cost pegfilgrastim biosimilars have been available for several years for patients requiring prophylaxis of febrile neutropenia. Different options for pegfilgrastim administration are also now available to accommodate specific patient preferences. As patients may want to minimize the risk of both neutropenia and SARS-CoV-2 infection, same-day administration is a pertinent option during the present COVID-19 pandemic. Therefore, individualized, patient-centered approaches and risk-management strategies should be considered when selecting the treatment and administration method for prophylaxis of febrile neutropenia. Three methods of administration would minimize hospital or clinic visits while also providing the prophylactic effect of G-CSF: same-day administration after chemotherapy, use of the US Food and Drug Administration-approved on-body injector delivering pegfilgrastim approximately 27 h after chemotherapy, or self-administration by the patient or caregiver > 24 h after chemotherapy. Choice of the specific administration option should be based on the patient's specific needs, while also considering mitigating factors, such as the economic burden associated with biologic medications and the risk of COVID-19. Pegfilgrastim biosimilars can minimize the additional financial burden on patients and the health care system during this pandemic and beyond.

Effects of medication intake in early pregnancy on the fetal fraction of cell-free DNA testing.

OBJECTIVES: To determine the association between medications intake in early pregnancy and variation in the fetal fraction (FF) in pregnant women undergoing cell-free DNA (cfDNA) testing. METHODS: We performed a retrospective cohort study of women (n = 1051) undergoing cfDNA testing at an academic center. The exposed group included women taking medications (n = 400; 38.1%), while the nonexposed group consisted of women taking no medications (n = 651; 61.9%). Our primary outcome was FF. We performed univariate and multivariate analyses as appropriate. RESULTS: The FFs were 8.8% (6.6-12.1), 8.7% (6.3-11.6), and 7.7% (5.1-9.3) among women taking 0, 1, and two or more medications, respectively (P < 0.01). Using multivariable linear mixed effects model, the mean FF was significantly lower among those taking two or more medications compared with the nonexposed group. FF was directly correlated with gestational age at the time of cfDNA testing and inversely correlated with maternal obesity. Exposure to metformin was associated with 1.8% (0.2-3.4) lower mean FF when compared with the nonexposed group (P = 0.02). Obesity and intake of two or more medications were associated with higher hazard ratio of having a low FF less than 4%. CONCLUSIONS: Exposure to metformin or two or more medications was associated with decreased FF, and obesity is associated with delay in achieving adequate FF percentage. These findings should be considered while counseling patients on test limitations.

Understanding the Legal Essentials of a Bowel Injury Lawsuit in Minimally Invasive Gynecologic Surgery.

Bowel injury is a known inherent complication of minimally invasive gynecologic surgery; however, it does not automatically signify medical malpractice. Plaintiff attorneys representing patients seeking legal recourse from a bowel injury typically allege claims of intraoperative negligence, delay in diagnosis, or lack of informed consent in an effort to circumvent the assertion that it is a known inherent complication. In addition, damage awards in bowel injury lawsuits can easily exceed the amount covered by the policy limits of a medical malpractice insurance plan, leaving the gynecologist financially responsible for the difference. Therefore, it is crucial to understand when it may be appropriate to consent to a settlement offer, which can relieve the gynecologist from financial liability for amounts awarded above the medical malpractice policy limits. The purpose of this medical-legal review is to make minimally invasive gynecologic surgeons more aware of the legal strategies used by plaintiff attorneys representing patients who have incurred bowel injuries, and how to limit liability in lawsuits.

Interactive effects of 9-cis-retinoic acid and androgen on proliferation, differentiation, and apoptosis of LNCaP prostate cancer cells.

9-cis-Retinoic acid (9cRA), which binds to both retinoic acid receptors and retinoic X receptors, inhibits prostate cancer induction in rats and reduces growth of prostate cancer cells. However, the nature of this growth inhibition and the interactive influence of androgens are not well defined and are the subject of this report. LNCaP and PC-3 cells were cultured and treated with a range of 9cRA concentrations for 3-6 days in the absence or presence of 5α-dehydrotestosterone. 9cRA inhibited cell proliferation in a dose-dependent manner, plateauing at 10 mol/l. Treatment of cells with 10 mol/l 9cRA inhibited 5α-dihydroxytestosterone (DHT)-stimulated proliferation, the effect of which was maximal at 10 mol/l DHT. Treatment of DHT (10 mol/l)-exposed cells with 9cRA caused a dose-dependent increase in prostate-specific antigen in the medium after 6 days, but not 3 days. 9cRA caused a dose-dependent increase in apoptotic cells stained with H33258 after 3 days, but not 6 days; however, on using flow cytometry, apoptosis was apparent at both 3 and 6 days. Flow cytometry also revealed interference of G0/G1 to S phase transition by 9cRA. Inhibition by 9cRA of anchorage-independent growth of PC-3 cells was also found; LNCaP cells did not grow colonies in soft agar. 9cRA inhibited growth and induced differentiation of human LNCaP prostate cancer cells in vitro and inhibited anchorage-independent growth of PC-3 cells. Because 9cRA and 13-cis-retinoic acid, which is retinoic acid receptor-selective, prevent prostate carcinogenesis in rats, and 13-cis-retinoic acid also inhibits growth of human prostate cancer cells, the RAR is a potential molecular target for prostate cancer prevention and therapy.

Glycosylation of Skp1 promotes formation of Skp1-cullin-1-F-box protein complexes in dictyostelium.

O(2) sensing in diverse protozoa depends on the prolyl 4 hydroxylation of Skp1 and modification of the resulting hydroxyproline with a series of five sugars. In yeast, plants, and animals, Skp1 is associated with F-box proteins. The Skp1-F-box protein heterodimer can, for many F-box proteins, dock onto cullin-1 en route to assembly of the Skp1-cullin-1-F-box protein-Rbx1 subcomplex of E3(SCF)Ub ligases. E3(SCF)Ub ligases conjugate Lys48-polyubiquitin chains onto targets bound to the substrate receptor domains of F-box proteins, preparing them for recognition by the 26S proteasome. In the social amoeba Dictyostelium, we found that O(2) availability was rate-limiting for the hydroxylation of newly synthesized Skp1. To investigate the effect of reduced hydroxylation, we analyzed knockout mutants of the Skp1 prolyl hydroxylase and each of the Skp1 glycosyltransferases. Proteomic analysis of co-immunoprecipitates showed that wild-type cells able to fully glycosylate Skp1 had a greater abundance of an SCF complex containing the cullin-1 homolog CulE and FbxD, a newly described WD40-type F-box protein, than the complexes that predominate in cells defective in Skp1 hydroxylation or glycosylation. Similarly, the previously described FbxA-Skp1CulA complex was also more abundant in glycosylation-competent cells. The CulE interactome also included higher levels of proteasomal regulatory particles when Skp1 was glycosylated, suggesting increased activity consistent with greater association with F-box proteins. Finally, the interactome of FLAG-FbxD was modified when it harbored an F-box mutation that compromised Skp1 binding, consistent with an effect on the abundance of potential substrate proteins. We propose that O(2)-dependent posttranslational glycosylation of Skp1 promotes association with F-box proteins and their engagement in functional E3(SCF)Ub ligases that regulate O(2)-dependent developmental progression.

Effect of soy protein isolate supplementation on biochemical recurrence of prostate cancer after radical prostatectomy: a randomized trial.

IMPORTANCE: Soy consumption has been suggested to reduce risk or recurrence of prostate cancer, but this has not been tested in a randomized trial with prostate cancer as the end point. OBJECTIVE: To determine whether daily consumption of a soy protein isolate supplement for 2 years reduces the rate of biochemical recurrence of prostate cancer after radical prostatectomy or delays such recurrence. DESIGN, SETTING, AND PARTICIPANTS: Randomized, double-blind trial conducted from July 1997 to May 2010 at 7 US centers comparing daily consumption of a soy protein supplement vs placebo in 177 men at high risk of recurrence after radical prostatectomy for prostate cancer. Supplement intervention was started within 4 months after surgery and continued for up to 2 years, with prostate-specific antigen (PSA) measurements made at 2-month intervals in the first year and every 3 months thereafter. INTERVENTION: Participants were randomized to receive a daily serving of a beverage powder containing 20 g of protein in the form of either soy protein isolate (n=87) or, as placebo, calcium caseinate (n=90). MAIN OUTCOMES AND MEASURES: Biochemical recurrence rate of prostate cancer (defined as development of a PSA level of ≥0.07 ng/mL) over the first 2 years following randomization and time to recurrence. RESULTS: The trial was stopped early for lack of treatment effects at a planned interim analysis with 81 evaluable participants in the intervention group and 78 in the placebo group. Overall, 28.3% of participants developed biochemical recurrence within 2 years of entering the trial (close to the a priori predicted recurrence rate of 30%). Among these, 22 (27.2%) occurred in the intervention group and 23 (29.5%) in the placebo group. The resulting hazard ratio for active treatment was 0.96 (95% CI, 0.53-1.72; log-rank P = .89). Adherence was greater than 90% and there were no apparent adverse events related to supplementation. CONCLUSION AND RELEVANCE: Daily consumption of a beverage powder supplement containing soy protein isolate for 2 years following radical prostatectomy did not reduce biochemical recurrence of prostate cancer in men at high risk of PSA failure. TRIAL REGISTRATION: clinicaltrials.gov Identifier: NCT00765479.

Decrease in stromal androgen receptor associates with androgen-independent disease and promotes prostate cancer cell proliferation and invasion.

Androgen receptor (AR) is expressed in both stromal and epithelial cells of the prostate. The majority of studies on AR expression and function in prostate cancer is focused on malignant epithelial cells rather than stromal cells. In this study, we examined the levels of stromal AR in androgen-dependent and -independent prostate cancer and the function of stromal AR in prostate cancer growth and invasion. We showed that stromal AR levels were decreased in the areas surrounding cancerous tissue, especially in androgen-independent cancer. Using two telomerase-immortalized human stromal cell lines, one AR-positive and the other AR-negative, we demonstrated that stromal cells lacking AR stimulated cell proliferation of co-cultured prostate cancer cells in vitro and enhanced tumour growth in vivo when co-injected with PC3 epithelial cells in nude mice. In contrast, stromal cells expressing AR suppressed prostate cancer growth in vitro and in vivo. In parallel with cancer growth, in vitro invasion assays revealed that stromal cells lacking AR increased the invasion ability of PC3 cell by one order of magnitude, while stromal cells expressing AR reduced this effect. These results indicate a negative regulation of prostate cancer growth and invasion by stromal AR. This provides potentially new mechanistic insights into the failure of androgen ablation therapy, and the reactivation of stromal AR could be a novel therapeutic approach for treating hormone refractory prostate cancer.

Radiographic determination of tissue thickness in paraffin blocks: application to the construction of tissue microarrays.

The determination of tissue thickness in paraffin blocks in the histology laboratory has been largely based on visual estimates. More accurate methods are required for the construction of tissue microarrays (TMAs) to assure a greater yield of cores in sections through the TMA block. We describe an accurate radiographic method to determine tissue thickness in donor paraffin blocks and have validated its application to TMA construction. Individual radiographic analysis was performed on paraffin donor blocks used for the construction of TMAs for determination of donor block tissue thickness. Consecutive numbered slide sections through the TMA block were then examined for the presence or loss of cores in the 150th TMA slide (from the final third of the TMA block) and correlated with the thickness of the individual donor blocks determined radiographically. At the 150th TMA slide, 202 of 1340 cores (15.1%) were depleted. Radiographic measurement showed a greater thickness of the donor paraffin block tissue (2.02 mm) corresponding to the retained cores as compared with the donor tissue (1.54 mm) of the depleted cores (P < 0.001). With progressive slide sections through a TMA block, the retention of tissue cores shows a significant correlation with donor block tissue thickness. Radiographic determination of tissue thickness in donor paraffin blocks can be used in TMA construction. Prior knowledge of tissue thickness in TMA construction can prompt compensatory steps that can enhance the yield of valuable samples and assure sufficient numbers of adequate cores for statistical analysis in biomarker evaluations.

Loss of B-cell translocation gene-2 in estrogen receptor-positive breast carcinoma is associated with tumor grade and overexpression of cyclin d1 protein.

The B-cell translocation gene-2 (BTG2) is present in the nuclei of epithelial cells in many tissues, including the mammary gland where its expression is regulated during glandular proliferation and differentiation in pregnancy. In immortalized mammary epithelial cells and breast cancer cells, BTG2 protein localized predominantly to the nucleus and cytoplasm, respectively. The highly conserved domains (BTG boxes A, B, and C) were required for regulating localization, suppression of cyclin D1 and growth inhibitory function of BTG2. Expression analysis of BTG2 protein in human breast carcinoma (n = 148) revealed the loss of nuclear expression in 46% of tumors, whereas it was readily detectable in the nuclei of adjacent normal glands. Loss of nuclear BTG2 expression in estrogen receptor-alpha (ERalpha)-positive breast tumors correlated significantly with increased histologic grade and tumor size. Consistent with its ability to suppress cyclin D1 transcription, loss of nuclear BTG2 expression in ER-positive breast carcinomas showed a significant correlation with cyclin D1 protein overexpression, suggesting that loss of BTG2 may be a factor involved in deregulating cyclin D1 expression in human breast cancer.

Regulation of de novo phosphatidylinositol synthesis.

Mechanisms that function to regulate the rate of de novo phosphatidylinositol (PtdIns) synthesis in mammalian cells have not been elucidated. In this study, we characterize the effect of phorbol ester treatment on de novo PtdIns synthesis in C3A human hepatoma cells. Incubation of cells with 12-O-tetradecanoyl phorbol 13-acetate (TPA) initially (1-6 h) results in a decrease in precursor incorporation into PtdIns; however, at later times (18-24 h), a marked increase is observed. TPA-induced glucose uptake from the medium is not required for observation of the stimulation of PtdIns synthesis, because the effect is apparent in glucose-free medium. Inhibition of the activation of arachidonic acid substantially blocks the synthesis of PtdIns but has no effect on the synthesis of phosphatidylcholine (PtdCho). Increasing the concentration of cellular phosphatidic acid by blocking its conversion to diacylglycerol, on the other hand, enhances the synthesis of PtdIns and inhibits the synthesis of PtdCho. The TPA-induced stimulation of PtdIns synthesis is not the result of the concomitant TPA-induced G1 arrest, because G1 arrest induced by mevastatin has no effect on PtdIns synthesis. Inhibition of protein kinase C activity blocks the stimulatory action of TPA on de novo synthesis of PtdIns but has no effect on TPA-induced inhibition. Potential sites of enzymatic regulation are discussed.

SOM230 inhibits insulin-like growth factor-I action in mammary gland development by pituitary independent mechanism: mediated through somatostatin subtype receptor 3?

Somatostatin analogs (SAs) treat acromegaly by lowering pituitary GH secretion, which, in turn, lowers systemic IGF-I. The profound systemic effect is often greater than expected in the face of only partial GH suppression. Here we report that the SA SOM230 can also act by a nonpituitary-mediated inhibition of IGF-I action. SOM230 inhibited mammary development in intact and hypophysectomized female rats, a process requiring IGF-I. IGF-I overcame this inhibition. SOM230 also inhibited other actions of IGF-I (inhibition of apoptosis, phosphorylation of insulin receptor substrate-1, and cell division). SOM230 did not reduce IGF-I mRNA abundance in mammary gland but did stimulate IGF binding protein 5 (IGFBP5). IGFBP5 was 3.75 times higher in mammary epithelium of SOM230 than in placebo animals (P < 0.001). Administration of IGFBP-5 also inhibited GH-induced mammary development (P < 0.001). Measurement of sstr(1-5) (somatostatin subtype receptor) by real-time RT-PCR revealed that the mammary glands had an abundance of sstr(3) and lower amounts of sstr(4) and sstr(5) but no sstr(1) or sstr(2.) That mammary development was also inhibited to a lesser degree than SOM230 by octreotide, whose main action is through sstr(2), strongly suggests that sstr(3) is at least in part mediating the effects of the SAs. We conclude that 1) SAs inhibit IGF-I action in the mammary gland through a novel nonpituitary mechanism; 2) IGFBP-5, here shown to inhibit pubertal mammary development, might mediate the effect; and 3) Measurement of available sstr receptors in the mammary gland suggests that sstr(3) mediates the SA activity, but sstr(5) is also a possible mediator.

Coexpression of MAST205 inhibits the activity of Na+/H+ exchanger NHE3.

Recent studies have shown that accessory proteins that interact with the apical Na(+)/H+ exchanger NHE3 are a vital part of the dynamic nature of the Na(+)/H+ exchanger regulation. We have identified MAST205, a microtubule-associated serine/threonine kinase with a molecular mass of 205 kDa that interacts with NHE3. MAST205 contains a S/T kinase domain and a PDZ domain that mediates interaction with NHE3. Northern blot analysis showed that MAST205 is highly expressed in human and rat kidney. Expression in opossum kidney (OK) cells showed that MAST205 is predominantly expressed in the apical membrane of the cells. Immunohistochemical studies demonstrated the presence of MAST205 at the apical region of the renal proximal tubules. Heterologous expression of MAST205 in OK cells inhibited endogenous NHE3 activity, and this inhibition required the presence of the kinase domain of MAST205, since deletion of the kinase domain or a dominant-negative mutant of MAST205 did not affect the activity of NHE3. Consistent with these results, we found that MAST205 phosphorylated NHE3 under in vitro conditions. However, overexpression of MAST205 did not affect expression of NHE3 proteins, suggesting that the effect of MAST205 was not mediated by a decrease in NHE3 expression. These findings suggest that MAST205 regulates NHE3 activity and, although the precise mechanism is yet to be determined, MAST205 appears to inhibit NHE3 activity through a phosphorylation-dependent mechanism.

BMP7 inhibits branching morphogenesis in the prostate gland and interferes with Notch signaling.

The mouse prostate gland develops by branching morphogenesis from the urogenital epithelium and mesenchyme. Androgens and developmental factors, including FGF10 and SHH, promote prostate growth (Berman, D.M., Desai, N., Wang, X., Karhadkar, S.S., Reynon, M., Abate-Shen, C., Beachy, P.A., Shen, M.M., 2004. Roles for Hedgehog signaling in androgen production and prostate ductal morphogenesis. Dev. Biol. 267, 387-398; Donjacour, A.A., Thomson, A.A., Cunha, G.R., 2003. FGF-10 plays an essential role in the growth of the fetal prostate. Dev. Biol. 261, 39-54), while BMP4 signaling from the mesenchyme has been shown to suppresses prostate branching (Lamm, M.L., Podlasek, C.A., Barnett, D.H., Lee, J., Clemens, J.Q., Hebner, C.M., Bushman, W., 2001. Mesenchymal factor bone morphogenetic protein 4 restricts ductal budding and branching morphogenesis in the developing prostate. Dev. Biol. 232, 301-314). Here, we show that Bone Morphogenetic Protein 7 (BMP7) restricts branching of the prostate epithelium. BMP7 is expressed in the periurethral urogenital mesenchyme prior to formation of the prostate buds and, subsequently, in the prostate epithelium. We show that BMP7(lacZ/lacZ) null prostates show a two-fold increase in prostate branching, while recombinant BMP7 inhibits prostate morphogenesis in organ culture in a concentration-dependent manner. We further explore the mechanisms by which the developmental signals may be interpreted in the urogenital epithelium to regulate branching morphogenesis. We show that Notch1 activity is associated with the formation of the prostate buds, and that Notch1 signaling is derepressed in BMP7 null urogenital epithelium. Based on our studies, we propose a model that BMP7 inhibits branching morphogenesis in the prostate and limits the number of domains with high Notch1/Hes1 activity.

Effect of neurokinins on canine prostate cell physiology.

BACKGROUND: Sensory peptide neurotransmitters have been implicated as significant regulators of prostate growth. This study was designed to evaluate the role of neurokinins in proliferation, differentiation, and contraction of canine prostate cells in culture. METHODS: NK1, NK2, and NK3 receptor subtypes were localized in canine prostate tissue by immunocytochemistry and ligand binding studies. Functional effects of neurokinin agonists were tested on cell differentiation (expression of smooth muscle actin (SMA)), proliferation (MTS assay), and contraction of canine prostate cells in culture. RESULTS: Immunocytochemical staining of canine prostate sections revealed strong stromal staining for NK1 together with weak stromal staining for NK2 and even weaker staining for NK3. Furthermore, there was overlapping localization of NK1 receptors, substance P (SP), and calcitonin gene-regulated peptide (CGRP) in prostate tissue sections. SP caused concentration-dependent increase in SMA expression that was attenuated in a concentration-dependent manner by YM-44778, a non-selective antagonist for neurokinin receptors, but not by either the NK2 antagonist (SR-48968) nor by the NK3 antagonist (SB-223412). SP and neurokinin A (NKA) also caused a modest contraction of stromal cells in collagen gels. NKA stimulated proliferation of prostate epithelial cells without any apoptotic effect, which was attenuated by SR-48968. Surprisingly, in binding studies NK3 appeared to be the most abundant neurokinin receptor subtype, although functional studies failed to reveal significant coupling of this receptor. CONCLUSIONS: Our results suggest that, at least in vitro, neurokinins have modest effects on canine prostate epithelial cell proliferation, stromal differentiation, and contraction.

Expression of the NF-kappaB-responsive gene BTG2 is aberrantly regulated in breast cancer.

BTG2, a p53-inducible antiproliferative gene, is stimulated in breast cancer cells by activation of nuclear factor kappa B (NF-kappaB). In rat mammary glands, BTG2 is expressed in epithelial cells and levels decreased during pregnancy and lactation but recovered during involution. Estrogen and progestin suppress BTG2 expression, suggesting that these steroids, which stimulate proliferation and lobuloalveolar development of mammary epithelial cells, may downregulate BTG2 in the mammary gland during pregnancy. Consistent with the report that BTG2 inhibits cyclin D1 expression, suppression of BTG2 mRNA in the mammary gland during gestation, and by estrogen and progestin, correlated with stimulation of cyclin D1. Ectopic expression of BTG2 inhibited breast cancer cell growth by arresting cells in the G1 phase, an effect reversed by cyclin D1. BTG2 expression was very low or undetectable in human breast cancer cell lines compared with nontumorigenic mammary epithelial cells, and nuclear expression of BTG2 was absent in 65% of human breast tumors compared with adjacent matched normal glands. Spontaneous mammary tumors arising in a mouse model with targeted expression of the early region of the SV40 large tumor Ag demonstrated loss of BTG2 protein very early during the tumorigenic process. Thus deregulation of BTG2 may be an important step in the development of mammary tumors.

The cooperative prostate cancer tissue resource: a specimen and data resource for cancer researchers.

PURPOSE: The Cooperative Prostate Cancer Tissue Resource (CPCTR) is a National Cancer Institute-supported tissue bank that provides large numbers of clinically annotated prostate cancer specimens to investigators. This communication describes the CPCTR to investigators interested in obtaining prostate cancer tissue samples. EXPERIMENTAL DESIGN: The CPCTR, through its four participating institutions, has collected specimens and clinical data for prostate cancer cases diagnosed from 1989 onward. These specimens include paraffin blocks and frozen tissue from radical prostatectomy specimens and paraffin blocks from prostate needle biopsies. Standardized histopathological characterization and clinical data extraction are performed for all cases. Information on histopathology, demography (including ethnicity), laboratory data (prostate-specific antigen values), and clinical outcome related to prostate cancer are entered into the CPCTR database for all cases. Materials in the CPCTR are available in multiple tissue formats, including tissue microarray sections, paraffin-embedded tissue sections, serum, and frozen tissue specimens. These are available for research purposes following an application process that is described on the CPCTR web site (www.prostatetissues.org). RESULTS: The CPCTR currently (as of October 2003) contains 5135 prostate cancer cases including 4723 radical prostatectomy cases. Frozen tissues, in some instances including patient serum samples, are available for 1226 cases. Biochemical recurrence data allow identification of cases with residual disease, cases with recurrence, and recurrence-free cases. CONCLUSIONS: The CPCTR offers large numbers of highly characterized prostate cancer tissue specimens, including tissue microarrays, with associated clinical data for biomarker studies. Interested investigators are encouraged to apply for use of this material (www.prostatetissues.org).

Induction of anoikis by doxazosin in prostate cancer cells is associated with activation of caspase-3 and a reduction of focal adhesion kinase.

The quinazoline family of alpha1-blockers (prazosin, doxazosin, and terazosin) induce apoptosis of prostate cells through an alpha1-adrenoceptor-independent mechanism. The objective of this study was to gain insight into the non-adrenergic, apoptotic mechanism of action of doxazosin in the prostate and the induction of anoikis by doxazosin. Primary cultures of benign prostate stromal and epithelial cells and the LNCaP (androgen sensitive) and PC-3 (androgen insensitive) prostate carcinoma cell lines were treated with doxazosin (0-50 microM). The effects of doxazosin on cell morphology, caspase-3 activity, and the expression levels of focal adhesion kinase (FAK) and integrin-linked kinase (ILK) were examined. Doxazosin induced changes in morphology consistent with anoikis in both benign and cancerous prostatic cells and increased caspase-3 activity. The effects were similar comparing benign cells (which express alpha1-adrenoceptors) and cancer cells (which do not express alpha1-adrenoceptors), but were more robust in benign cells. Norepinephrine had no effect on doxazosin-induced cell morphology or caspase-3 activity. Treatment of PC-3 cells with doxazosin significantly reduced the protein levels of FAK but did not significantly affect the levels of ILK. These findings suggest that doxazosin induces apoptosis and anoikis of prostate cancer cells by a mechanism of action that is alpha1-adrenoceptor independent. The apoptosis of cancer cells induced by doxazosin counteracts cell proliferation and may have the potential of retarding or reversing prostate cancer cell growth.

Lipid metabolism in phosphatidylinositol transfer protein alpha-deficient vibrator mice.

Mice that are homozygous for the vibrator mutation express 65-85% less phosphatidylinositol transfer protein alpha (PITPalpha) than their wild type litter mates. By postnatal day 10-12 (P10-12) they exhibit signs of neurodegeneration and die prematurely by P40. In the present study, we examine the lipid content of brain, liver, and mammary glands from these animals. Lipid-mediated signal transduction is evaluated in primary fibroblast cultures. With respect to the lipid make-up of brain and liver, we report that there is a significant increase (2- to 4-fold) in the neutral lipids present in the livers of vb/vb animals when compared with wild type (+/+) litter mates. No significant changes are observed in the brains of these animals. The mammary glands of vb/vb mice are underdeveloped with respect to ductal and alveolar structures, and the fat pad is composed of predominantly brown adipose tissue rather than the white adipose tissue characteristic of age-matched wild type litter mates. No differences are observed in any aspect of lipid-mediated signal transduction.