The impact of ethical implications intertwined with tuberculosis household contact investigation: a qualitative study.

Background: Household contact investigation (HCI) is an effective and widely used approach to identify persons with tuberculosis (TB) disease and infection, globally. Despite widespread recommendations for the use of HCI, there remains poor understanding of the impact on and value of contact investigation for participants. Further, how HCI as a practice impacts psychosocial factors, including stigma and possible unintended disclosure of illness among persons with TB, their families, and communities, is largely unknown. Methods: This exploratory qualitative study nested within a randomized trial (ClinicalTrials.gov: NCT04520113, 17 August 2020) was conducted in South Africa to understand the impacts of HCI on index patients living with TB and their household contact persons in two rural districts in the Limpopo province (Vhembe and Capricorn) and Soshanguve, a peri-urban township in Gauteng province. People with TB and household members of people with TB were recruited to participate in in-depth interviews and focus group discussions using semi-structured guides. We explored individual, interpersonal, and community-level perceptions of potential impacts of household contact investigation to elucidate their perceptions of HCI. Thematic analysis identified key themes. Results: Twenty-four individual interviews and six focus group discussions (n=39 participants) were conducted. Participants viewed HCI as an effective approach to finding TB cases, helpful in educating households about TB symptoms and reducing barriers to health-related services. At the interpersonal level, HCI aided people with TB in safely disclosing their TB status to family members and facilitated family and social support for accountability. The introduction of HIV testing during HCI was reported by some participants as making household members slightly uncomfortable, decreasing interest in household members being tested for TB. HCI negatively impacted community-level TB and HIV-related stigma due to healthcare worker visibility at home. Conclusion: Our data suggests varying impacts of HCI on people with TB, their families and interpersonal relationships, and communities, highlighting the importance of considering approaches that address concerns about community stigma and HIV testing to enhance acceptance of HCI.

Perceived stigma among people with TB and household contacts.

BACKGROUND: TB-related stigma hampers access to diagnosis and treatment, making it important to understand the demographic and clinical characteristics associated with perceived TB stigma. TB stigma has not been studied in household contacts before, yet they comprise an important population for epidemic control, with high risk of infection.METHOD: A cross-sectional study was conducted among people with TB and household contacts in South Africa using a 12-item perceived TB stigma scale (score range: 0-36). Demographic and clinical characteristic data were collected using a close-ended questionnaire. A linear mixed-effects regression model was used to explore perceived TB stigma levels and its associated characteristics.RESULTS: The sample included 143 people with TB and 135 household contacts. The mean perceived TB stigma score among people with TB was 22.1 (95% CI 21.1-23.1) and 22.2 (95% CI 21.1-23.3) among household contacts. Being in the same household explained 24.3% variability in stigma perception. Residence in the urban study site (Soshanguve) and a positive HIV diagnosis were associated with higher perceived TB stigma score.CONCLUSIONS: People with TB and household contacts have similarly high prevalence of perceived TB stigma. Positive HIV status and urban location were associated with higher prevalence of perceived TB stigma.

Time to care-seeking for TB symptoms.

BACKGROUND: Early presentation to healthcare facilities is critical for early diagnosis and treatment of TB. We studied self-reported time to care-seeking from the onset of TB symptoms among primary healthcare clinic (PHC) attendees in Limpopo Province, South Africa.METHODS: We used data from participants enrolled in a cluster-randomized trial of TB case finding in 56 PHC clinics across two health districts. We fitted log-normal accelerated failure time regression models and we present time ratios (TRs) for potential risk factors.RESULTS: We included 2,160 participants. Among the 1,757 (81%) diagnosed with active TB, the median time to care-seeking was 30 days (IQR 14-60); adults sought care later than children/adolescents (adjusted TR aTR 1.47, 95% CI 1.10-1.96). Among those not diagnosed with TB, the median was 14 days (IQR 7-60); being HIV-positive (aTR 1.57, 95% CI 1.03-2.40); having less than grade 8 education and currently smoking were associated with longer time to care-seeking. In the combined analysis, living with HIV and having underlying active TB was associated with faster care-seeking (TB status x HIV interaction: TR 0.68, 95% CI 0.48-0.96).CONCLUSION: Delay in care-seeking was associated with age, lower education and being a current smoker. TB awareness campaigns targeting these population groups may improve care-seeking behavior and reduce community TB transmission.

Geographic mobility and time to seeking care among people with TB in Limpopo, South Africa.

SETTING: Human mobility contributes to the spread of infectious diseases. South Africa has a long history of internal labor migration and a high burden of TB.METHODS: People newly diagnosed with TB in the Vhembe and Waterberg Districts of Limpopo answered a questionnaire regarding geographic movement over the past year. Participants were classified as 'highly mobile' (spending more than 30 nights at a residence other than their primary residence in the past year, or being ≥250 km from their primary residence at the time of the interview) or 'less mobile'. We explored associations between sociodemographic characteristics and high mobility, and between mobility and time to presentation at a clinic.RESULTS: Of the 717 participants included, 185 (25.7%) were classified as 'highly mobile'. Factors associated with high mobility included living with someone outside of Limpopo Province, HIV-positive status (men only), and current smoking (men only). Highly mobile individuals had similar care-seeking behavior as less mobile individuals (adjusted time ratio 0.9, 95% CI 0.6-1.2, P = 0.304)CONCLUSION: Highly mobile people with TB in Limpopo Province were more likely to live with people from outside the province, smoke, and have HIV. These patients had similar delays in seeking care as less mobile individuals.

Gaps in the tuberculosis preventive therapy care cascade in children in contact with TB.

BACKGROUND: Young children (<5 years) and children living with HIV in contact with an adult with tuberculosis (TB) should receive TB preventive therapy (TPT), but uptake is low. AIMS: To determine gaps in the uptake of and adherence to TPT in child TB contacts under routine primary care clinic conditions. METHODS: A cohort of child TB contacts (age <5 years or living with HIV <15 years) was followed at a primary care clinic in Johannesburg, South Africa. RESULTS: Of 170 child contacts with 119 adult TB cases, only 45% (77/170) visited the clinic for TPT eligibility screening, two of whom had already initiated TPT at another clinic. Of the 75 other children, 18/75 (24%) commenced TB treatment and 56/75 (75%) started TPT. Health-care workers followed the guidelines, with 96% (64/67) of children screened for symptoms of TB and 97% (36/37) of those symptomatic assessed for TB, but microbiological testing was low (9/36, 25%) and none had microbiologically confirmed tuberculosis. Only half (24/46, 52%) of the children initiating TPT completed the 6-month course. Neither sociodemographic determinants (age, sex) nor clinical factors (HIV status, TB source, time to TPT initiation) was associated with non-adherence to TPT. CONCLUSION: Most child contacts of an adult TB case do not visit the clinic, and half of those initiating TPT did not adhere to the full 6-month course. These programme failures result in missed opportunities for early diagnosis of active TB and prevention of progression to disease in young and vulnerable children.

Priorities among HIV-positive individuals for tuberculosis preventive therapies.

BACKGROUND: There has been slow uptake of isoniazid preventive therapy (IPT) among people living with HIV (PLWH).METHODS: We surveyed adults recently diagnosed with HIV in 14 South African primary health clinics. Based on the literature and qualitative interviews, sixteen potential barriers and facilitators related to preventive therapy among PLWH were selected. Best-worst scaling (BWS) was used to quantify the relative importance of the attributes. BWS scores were calculated based on the frequency of participants' selecting each attribute as the best or worst among six options (across multiple choice sets) and rescaled from 0 (always selected as worst) to 100 (always selected as best) and compared by currently receiving IPT or not.RESULTS: Among 342 patients surveyed, 33% (n = 114) were currently taking IPT. Having the same standard of life as someone without HIV was most highly prioritized (BWS score = 67.3, SE = 0.6), followed by trust in healthcare providers (score, 66.3 ± 0.6). Poor standard of care in public clinics (score, 30.6 ± 0.6) and side effects of medications (score, 33.7 ± 0.6) were least prioritized. BWS scores differed by IPT status for few attributes, but overall ranking was similar (spearman's rho = 0.9).CONCLUSION: Perceived benefits of preventive therapy were high among PLWH. IPT prescription by healthcare providers should be encouraged to enhance IPT uptake among PLWH.

Tuberculosis patients with higher levels of poverty face equal or greater costs of illness.

SETTING: Fifty-six public clinics in Limpopo Province, South Africa.OBJECTIVE: To evaluate the association between tuberculosis (TB) patient costs and poverty as measured by a multidimensional poverty index.DESIGN: We performed cross-sectional interviews of consecutive patients with TB. TB episode costs were estimated from self-reported income, travel costs, and care-seeking time. Poverty was assessed using the South African Multidimensional Poverty Index (SAMPI) deprivation score (a 12-item household-level index), with higher scores indicating greater poverty. We used multivariable linear regression to adjust for age, sex, human immunodeficiency virus status and travel time.RESULTS: Among 323 participants, 108 (33%) were 'deprived' (deprivation score >0.33). For each 0.1-unit increase in deprivation score, absolute TB episode costs were 1.11 times greater (95%CI 0.97-1.26). TB episode costs were 1.19 times greater with each quintile of higher deprivation score (95%CI 1.00-1.40), but lower by a factor of 0.54 with each quintile of lower self-reported income (higher poverty, 95%CI 0.46-0.62).CONCLUSION: Individuals experiencing multidimensional poverty and the cost of tuberculosis illness in Limpopo, South Africa faced equal or higher costs of TB than non-impoverished patients. Individuals with lower self-reported income experienced higher costs as a proportion of household income but lower absolute costs. Targeted interventions are needed to reduce the economic burden of TB on patients with multidimensional poverty.

Risk factors for catastrophic costs associated with tuberculosis in rural South Africa.

Fifty-five public clinics in northern South Africa. To estimate patient costs and identify the factors associated with catastrophic costs among individuals treated for tuberculosis (TB). We performed cross-sectional interviews of consecutive patients at public clinics from October 2017 to January 2018. 'Catastrophic costs' were defined as costs totalling ≥20% of annual household income. For participants with no reported income, we considered scenarios where costs were considered non-catastrophic if 1) costs totalled Among 327 participants, the estimated mean TB episode costs were US$365 (95%CI 233-498): out-of-pocket costs comprised 58% of costs, wages lost due to health care-seeking represented 26%, and income reduction accounted for 16% of costs. Ninety (28%) participants experienced catastrophic costs, which were associated with clinic travel times of 60-90 min (adjusted prevalence ratio [aPR] 1.7, 95%CI 0.9-3.1), unemployment (aPR 2.0, 95%CI 1.0-4.0) and having fewer household members (aPR 0.6, 95%CI 0.3-1.0). In rural South Africa, catastrophic costs from TB are common and associated with distance to clinics, unemployment, and household size. These findings can help tailor social protection programs and enhance service delivery to patients at greatest risk of experiencing financial hardship. .

The unmet needs and health priorities of the urban poor: Generating the evidence base for urban community health worker programmes in South Africa.

BACKGROUND: There is a growing interest in involving community health workers (CHWs) into the formal healthcare system in South Africa (SA). OBJECTIVES: To generate evidence for defining CHW tasks in urban SA. METHODS: A cross-sectional survey of residents of Diepsloot, northern Johannesburg, was performed using geographically weighted random sampling, with home-based health assessment and a questionnaire on sociodemographics, medical history, experience of violence, health-seeking behaviour and perceived health priorities. RESULTS: Between May 2013 and March 2014, 1 230 adults participated. Self-reported medical conditions included hypertension (12%), HIV (10%), diabetes (3%), cancer (1%) and mental illness (1%). Health assessments identified a high prevalence of undiagnosed conditions: hypertension (26%), obesity or overweight (46%), mild to severe depression (23%), HIV infection (5.8%) and tuberculosis (TB) (0.4%). Among women, 18% had unmet family planning needs and 77% had never had a Pap smear. Sexually transmitted infection symptoms were reported by 7% of participants. Physical violence was widespread, with 13% having experienced and 16% witnessing violence in the past year, with women mostly experiencing violence at home and men in the community. Participants' top health concerns were crime, safety and violence (49%) and HIV (18%); healthy living/weight control was listed by only 8% of participants. CONCLUSIONS: Alignment of CHW roles to unmet health needs and perceived health priorities will be important for optimal impact of CHW programmes in urban communities. Our data suggest that the CHW role should expand from a traditional focus on HIV, TB and maternal health to include non-communicable diseases, healthy lifestyle, and the intersection of violence and health.

Cost-effectiveness of universal isoniazid preventive therapy among HIV-infected pregnant women in South Africa.

OBJECTIVE: To estimate the incremental cost-effectiveness of universal vs. test-directed treatment of latent tuberculous infection (LTBI) among human immunodeficiency virus (HIV) positive pregnant women in South Africa. METHODS: We compared tuberculin skin test (TST) directed isoniazid preventive therapy (IPT) (TST placement with delivery of IPT to women with positive results) against QuantiFERON®-TB Gold In-Tube (QGIT) directed IPT and universal IPT using decision analysis. Costs were measured empirically in six primary care public health clinics in Matlosana, South Africa. The primary outcome was the incremental cost-effectiveness ratio, expressed in 2016 US$ per disability-adjusted life-year (DALY) averted. RESULTS: We estimated that 29.2 of every 1000 pregnant women would develop TB over the course of 1 year in the absence of IPT. TST-directed IPT reduced this number to 24.5 vs. 22.6 with QGIT-directed IPT and 21.0 with universal IPT. Universal IPT was estimated to cost $640/DALY averted (95% uncertainty range $44-$3146) relative to TST-directed IPT and was less costly and more effective (i.e., dominant) than QGIT-directed IPT. Cost-effectiveness was most sensitive to the probability of developing TB and LTBI prevalence. CONCLUSION: Providing IPT to all eligible women can be a cost-effective strategy to prevent TB among HIV-positive pregnant women in South Africa.

Higher cost of implementing Xpert(®) MTB/RIF in Ugandan peripheral settings: implications for cost-effectiveness.

SETTING: Initial cost-effectiveness evaluations of Xpert(®) MTB/RIF for tuberculosis (TB) diagnosis have not fully accounted for the realities of implementation in peripheral settings. OBJECTIVE: To evaluate costs and diagnostic outcomes of Xpert testing implemented at various health care levels in Uganda. DESIGN: We collected empirical cost data from five health centers utilizing Xpert for TB diagnosis, using an ingredients approach. We reviewed laboratory and patient records to assess outcomes at these sites and10 sites without Xpert. We also estimated incremental cost-effectiveness of Xpert testing; our primary outcome was the incremental cost of Xpert testing per newly detected TB case. RESULTS: The mean unit cost of an Xpert test was US$21 based on a mean monthly volume of 54 tests per site, although unit cost varied widely (US$16-58) and was primarily determined by testing volume. Total diagnostic costs were 2.4-fold higher in Xpert clinics than in non-Xpert clinics; however, Xpert only increased diagnoses by 12%. The diagnostic costs of Xpert averaged US$119 per newly detected TB case, but were as high as US$885 at the center with the lowest volume of tests. CONCLUSION: Xpert testing can detect TB cases at reasonable cost, but may double diagnostic budgets for relatively small gains, with cost-effectiveness deteriorating with lower testing volumes.

The patient impact of point-of-care vs. laboratory placement of Xpert(®) MTB/RIF.

BACKGROUND: The Xpert(®) MTB/RIF assay can diagnose tuberculosis (TB) rapidly and with great accuracy. The effect of Xpert placement at point of care (POC) vs. at an off-site laboratory on patient management remains unknown. DESIGN: At a primary care clinic in Johannesburg, South Africa, we compared TB diagnosis and treatment initiation among 1861 individuals evaluated for pulmonary TB using Xpert performed either at POC or offsite. RESULTS: When Xpert was performed at POC, a higher proportion of Xpert-positive individuals started treatment (95% vs. 87%, P = 0.047) and time to treatment initiation was shorter (median 0 vs. 5 days, P < 0.001). In contrast, among Xpert-negative TB cases, a higher proportion (87% vs. 72%, P = 0.001) started treatment when the sample was sent to the laboratory, with a shorter time to treatment (median 9 vs. 13 days, P = 0.056). While the overall proportion of presumed TB patients starting treatment was independent of Xpert placement, the proportion started based on a bacteriologically confirmed diagnosis was higher when Xpert was performed at POC (73% vs. 58%, P = 0.006). CONCLUSIONS: Placement of Xpert at POC resulted in more Xpert-positive patients receiving treatment, but did not increase the total number of presumed TB patients starting treatment. When samples were sent to a laboratory for Xpert testing, empiric decision making increased.

A home tracing program for contacts of people with tuberculosis or HIV and patients lost to care.

SETTING: Primary care clinic serving a high tuberculosis (TB) and human immunodeficiency virus (HIV) prevalence community in South Africa. OBJECTIVE: To evaluate a program combining TB and HIV contact investigation with tracing of individuals lost to TB or HIV care. DESIGN: Contacts were offered home-based HIV testing, TB symptom screening, sputum collection and referral for isoniazid preventive therapy (IPT). Effectiveness was assessed by the number needed to trace (NNT). RESULTS: Only 419/1197 (35.0%) households were successfully traced. Among 267 contacts, we diagnosed 27 new HIV cases (10 linked to care) and two TB cases (both initiated treatment) and three started IPT. Of 630 patients lost to care, 132 (21.0%) were successfully traced and 81 (61.4%) re-engaged in care. The NNT to locate one individual lost to care was 4.8 (95%CI 4.1-5.6), to re-engage one person in care 7.8 (95%CI 6.4-9.7), to diagnose one contact with HIV 44.3 (95%CI 30.6-67.0), to link one newly diagnosed contact to HIV care 120 (95%CI 65.3-249.2) and to find one contact with active TB and initiate treatment 599 (95%CI 166.0-4940.7). CONCLUSION: The effectiveness of this contact tracing approach in identifying new TB and HIV cases was low. Methods to optimize contact investigation should be explored and their cost-effectiveness assessed.

General practice career intentions among graduate-entry students: a cross-sectional study at Ireland's newest medical school.

Increased care provision and clinical activity in General Practice in Ireland will have important manpower implications. Recent developments in medical education policy including the introduction of graduate-entry medical degree programmes may help address this issue. The aim of this study was to determine GP career intentions among students on an Irish graduate-entry medical degree programme and to identify factors that influence these. An electronic cross-sectional study of students at University of Limerick Graduate-Entry Medical School (UL-GEMS) was undertaken. We received 139 replies (78% response rate). 41 (29%) reported GP was their current preferred career choice, while 29 (19%) reported it was their preferred career choice on entry to medical school. This first study to present data on GP career intentions among graduate-entry students in Ireland highlights the specialty as a popular preferred career choice among students, both on entry to, and during medical school. The study also identifies factors which are likely to be important in determining career intentions. Further research to examine this issue at other graduate-entry medical schools in Ireland and to determine whether our findings are pursued over time amongst graduates is a priority.

Point-of-care Xpert® MTB/RIF for smear-negative tuberculosis suspects at a primary care clinic in South Africa.

OBJECTIVE: To assess the clinical utility and cost of point-of-care Xpert® MTB/RIF for the diagnosis of smear-negative tuberculosis (TB). DESIGN: Cohort study of smear-negative TB suspects at a South African primary care clinic. Participants provided one sputum sample for fluorescent smear microscopy and culture and an additional sample for Xpert. Outcomes of interest were TB diagnosis, linkage to care, patient and provider costs. RESULTS: Among 199 smear-negative TB suspects, 16 were positive by Xpert, 15 by culture and 7 by microscopy. All cases identified by Xpert began anti-tuberculosis treatment the same or next day; only one of five Xpert-negative culture-positive cases started treatment after 34 days. Xpert at point of care offered similar diagnostic yield but a faster turnaround time than smear and culture performed at a centralized laboratory. Compared to smear plus culture, Xpert (at US$9.98 per cartridge) was US$3 less expensive per valid result (US$21 vs. US$24) and only US$6 more costly per case identified (US$266 vs. US$260). CONCLUSION: Xpert is an effective method of diagnosing smear-negative TB. It is cost saving for patients, especially if performed at point of care, but it is costly for health care providers. Data-driven studies are needed to determine its cost-effectiveness in resource-poor settings with diverse diagnostic practices.

Provider utilization of high-risk donor organs and nucleic acid testing: results of two national surveys.

Fears of infectious transmission from CDC high-risk donors (HRDs) remain a significant disincentive, and the potential for human immunodeficiency virus/hepatitis C virus (HIV/HCV) nucleic acid testing (NAT) to allay these fears remains unstudied. We hypothesized that NAT, which narrows the window period between infection and detectability compared to the standard ELISA, might lead to increased provider willingness to use HRDs. Between January and April 2008, we performed two national surveys: one of current NAT practice among organ procurement organizations (OPOs); a second of HRD use among transplant surgeons. Surgeons who reported accepting 10% or more offers for a given HRD behavior and organ type were classified as 'high utilizers' of that subgroup. We built hierarchical models to examine associations between OPO NAT performance and provider utilization. Providers who ranked medical risks of HIV or HCV as important disincentives to HRD use had significantly lower odds of being high utilizers (HIV odds ratio 0.22, HCV odds ratio 0.41, p < 0.005). Furthermore, both HIV and HCV NAT performance were associated with significantly higher odds of being high utilizers (HIV odds ratio 1.58, HCV 2.69, p < 0.005). The demonstrated associations between OPO NAT performance and high provider utilization of HRDs should be considered in the ongoing debate about NAT in transplantation.

Formal policies and special informed consent are associated with higher provider utilization of CDC high-risk donor organs.

A new United Network for Organ Sharing (UNOS) policy mandates special informed consent (SIC) before transplanting organs from donors classified by the Public Health Service/Center for Disease Control (PHS/CDC) as high-risk donors (HRDs); however, concerns remain that this policy may cause suboptimal organ utilization. Currently, consent and disclosure policy is determined by individual centers or surgeons; as such, little is known about current practices. The goals of this study were to quantify consent and disclosure practices for HRDs in the United States, identify factors associated with SIC use and analyze associations between SIC use and HRD organ utilization. We surveyed 422 transplant surgeons about their use of HRD organs and their associated consent and disclosure practices. In total, 52.7% of surgeons use SIC, but there is a high variation in use within centers, between centers and by donor behavior. A defined HRD policy at a transplant center is strongly associated with SIC use at that center (OR = 4.68, p < 0.001 by multivariate hierarchical logistic regression). SIC use is associated with higher utilization of HRD livers (OR 3.37), and a trend toward higher utilization of HRD kidneys (OR 1.74) and pancreata (OR 1.28). We believe our findings support a formalized national policy and suggest that this policy will not result in decreased utilization.

Viral nucleic acid testing (NAT) and OPO-level disposition of high-risk donor organs.

The use of Public Health Service/Centers for Disease Control and Prevention (PHS/CDC) high-risk donor (HRD) organs remains controversial, especially in light of a recent high-profile case of human immunodeficiency virus (HIV) and hepatitis C virus (HCV) transmission. Nucleic acid testing (NAT), while more expensive and time consuming, reduces infectious risk by shortening the period between infection and detectability. The purpose of this study was to characterize HRDs and disposition of their organs by organ procurement organization (OPO), to measure NAT practices by OPO and to examine associations between NAT practices and use of HRD organs. We analyzed 29 950 deceased donors (2574 HRDs) reported to UNOS since July 1, 2004 and May 8, 2008. We then surveyed all OPO clinical directors about their use of NAT, average time to receive NAT results, locations where NAT is performed and percentage of the time NAT results are available for allocation decisions. In total, 51.7% of OPOs always perform HIV NAT, while 24.1% never do. A similar pattern is seen for HCV NAT performance, while the majority (65.6%) never perform HBV NAT. AIDS prevalence in an OPO service area is not associated with NAT practice. OPOs that perform HIV NAT are less likely to export organs outside of their region. The wide variation of current practice and the possibility that NAT would improve organ utilization support consideration for a national policy.

Rapamycin induces Smad activity in prostate cancer cell lines.

Rapamycin inhibits the FK506-binding protein 12 (FKBP12)/mammalian target of rapamycin (mTOR) complex and causes cell cycle arrest in G1. The precise mechanism of growth inhibition by rapamycin is only partly understood. Rapamycin led to growth inhibition in the human prostate cancer cell lines LNCaP and PC3 cells after 72 h, ID50: 93 and 50 nM, respectively. Filter cDNA array analysis showed down-regulation by more than 0.75x by rapamycin in PC3 cells and LNCaP cells of the following genes: follistatin, eukaryotic initiation factor-4E (eIF4E), glucose-6-phosphate dehydrogenase (GAPDH), lactate dehydrogenase (LDH)-A, ATP synthase, heat shock protein (HSP)-1. Upregulation by more than 1.5x was found for: bone morphogenetic protein (BMP)-4, FKBP12, carcinoma embryonic antigen (CEA) precursor, eukaryotic initiation factor (eIF)-3 p36 subunit, latent transforming growth factor (TGF) beta binding protein (LTBP)1. Rapamycin induced BMP4 and reduced follistatin expression in PC3 cells. This resulted in a dose-dependent nuclear expression of Smad4 and activated the SBE4 Smad-reporter, indicating activation of TGFbeta/BMP signaling. Combining rapamycin with PI3K inhibition (LY294002) increased growth inhibition. These findings illustrate that Smad signaling plays a role in the anticancer effects of rapamycin and show that combination with PI3K inhibition improves growth inhibition.

Hypoxia-inducible factor 1alpha and 1beta proteins share common signaling pathways in human prostate cancer cells.

Hypoxia-inducible factor 1 (HIF-1) is a heterodimeric transcription factor consisting alpha and beta subunits. It is critically involved in cancer cell hypoxia adaptation, glycolysis, and angiogenesis. HIF-1beta is associated with HIF-1 functions as a dimerization partner of HIF-1alpha, and is on the other hand associated with carcinogenesis via dioxin signaling. Regulation of HIF-1beta protein expression was investigated in human prostate cancer (PCA) cells. HIF-1beta protein was expressed constitutively under nonhypoxic conditions in all human PCA cells tested, and was up-regulated by hypoxia, CoCl2, EGF, serum, or PMA in moderate levels. Compared to that of HIF-1alpha, the constitutive, serum-, EGF-, and PMA-increased HIF-1beta protein expression were also inhibited by selective PI3K or FRAP/TOR inhibitors but in higher doses. Hypoxia partially reversed the dose dependent inhibition of HIF-1beta. These results suggest that HIF-1alpha and beta share common signaling pathways for nuclear protein accumulation.