Diabetes and pancreatic cancer risk in a multiracial cohort.

AIMS: To determine the relationship of diabetes with pancreatic cancer incidence among African American and Whites of similar socio-economic status. METHODS: Using the Southern Community Cohort Study, we conducted a follow-up during 2002-2015 of pancreatic cancer incidence of 73,378 mostly low-income participants aged 40-79 years; 15,913 reported diabetes at baseline. Multivariable Cox analysis controlling for sex, family history of pancreatic cancer, BMI, smoking status, alcohol consumption, education, income and other important covariates, and with age as the timescale was used. RESULTS: Totally, 265 incident pancreatic cancer cases were observed. Pancreatic cancer risk was increased among those with diabetes (HR 1.54, CI 1.16-2.05), with similar increases among African Americans (HR 1.51, CI 1.08-2.11) and Whites (HR 1.78, CI 1.00-3.16). No trend in risk was observed for diabetes duration among those with diabetes, with HRs of 1.39 (0.91-2.11), 2.31 (1.51-3.54) and 1.23 (0.80-1.89) for <5, 5-9 and 10+ years duration, respectively. African Americans were at increased risk of pancreatic cancer (HR = 1.40, 95% CI 1.05-1.87), which persisted after adjusting for diabetes (HR 1.36, CI 1.02-1.81). The effect sizes for other pancreatic cancer risk factors with pancreatic cancer were similar by diabetes status, although a stronger association with low BMI was evident among those with diabetes. CONCLUSIONS: Diabetes increases pancreatic cancer risk similarly among African Americans and Whites in this Southern U.S.

Longitudinal Assessment of Multimorbidity Medication Patterns among Smokers in the COPDGene Cohort.

Background and objectives: Chronic obstructive pulmonary disease (COPD) is usually comorbid with other chronic diseases. We aimed to assess the multimorbidity medication patterns and explore if the patterns are similar for phase 1 (P1) and 5-year follow-up phase 2 (P2) in the COPDGene cohort. Materials and Methods: A total of 5564 out of 10,198 smokers from the COPDGene cohort who completed 2 visits, P1 and P2 visits, with complete medication use history were included in the study. We conducted latent class analysis (LCA) among the 27 categories of chronic disease medications, excluding COPD treatments and cancer medications at P1 and P2 separately. The best number of LCA classes was determined through both statistical fit and interpretation of the patterns. Results: We found four classes of medication patterns at both phases. LCA showed that both phases shared similar characteristics in their medication patterns: LC0: low medication; LC1: hypertension (HTN) or cardiovascular disease (CVD)+high cholesterol (Hychol) medication predominant; LC2: HTN/CVD+type 2 diabetes (T2D) +Hychol medication predominant; LC3: Hychol medication predominant. Conclusions: We found similar multimorbidity medication patterns among smokers at P1 and P2 in the COPDGene cohort, which provides an understanding of how multimorbidity medication clustered and how different chronic diseases combine in smokers.

Racial Differences in Hepatocellular Carcinoma Incidence and Risk Factors among a Low Socioeconomic Population.

The purpose of this study was to examine differences in risk factors associated with hepatocellular carcinoma (HCC) among White and African Americans from low socioeconomic backgrounds in the Southern Community Cohort Study (SCCS). The SCCS is a prospective cohort study with participants from the southeastern US. HCC incidence rates were calculated. Multivariable Cox regression was used to calculate HCC-adjusted hazard ratios (aHR) associated with known baseline HCC risk factors for White and African Americans, separately. There were 294 incident HCC. The incidence rate ratio for HCC was higher (IRR = 1.4, 95%CI: 1.1-1.9) in African Americans compared to White Americans. White Americans saw a stronger association between self-reported hepatitis C virus (aHR = 19.24, 95%CI: 10.58-35.00) and diabetes (aHR = 3.55, 95%CI: 1.96-6.43) for the development of HCC compared to African Americans (aHR = 7.73, 95%CI: 5.71-10.47 and aHR = 1.48, 95%CI: 1.06-2.06, respectively) even though the prevalence of these risk factors was similar between races. Smoking (aHR = 2.91, 95%CI: 1.87-4.52) and heavy alcohol consumption (aHR = 1.59, 95%CI: 1.19-2.11) were significantly associated with HCC risk among African Americans only. In this large prospective cohort, we observed racial differences in HCC incidence and risk factors associated with HCC among White and African Americans.

Diabetes and liver cancer risk: A stronger effect in Whites than Blacks?

BACKGROUND: Both diabetes and liver cancer are overrepresented among African Americans, but limited information is available on the interrelationship of these two diseases among African Americans. We examined the association of diabetes with the incidence of liver cancer and whether this varied by participant self-reported race/ethnicity. METHODS: Using the Southern Community Cohort Study, we conducted a cancer follow up (2002-2016) of a cohort of mostly low-income participants aged 40-79 with diabetes (n = 15,879) and without diabetes (n = 59,077) at study baseline. Cox regression was used to compute Hazard Ratios (HR) and 95% CIs for the risk of incident liver cancer. RESULTS: With 790,132 person years of follow up, 320 incident cases of liver cancer were identified. In analyses controlling for age, sex, race, BMI, current and former smoking, total alcohol consumption, family history of liver cancer, any hepatitis infection, hyperlipidemia and socioeconomic factors, the association between diabetes and risk of liver cancer differed significantly (pinteraction = 0.0001) between participants identifying as Black/African American (AA) or White/European American (EA). Diabetes was associated with 5.3-fold increased cancer risk among EAs (HR 5.4, 95% CI 3.2-9.3) vs an 80% increase (HR 1.8, 95% CI 1.3-2.5) among AAs. Furthermore, controlling for diabetes greatly attenuated the higher risk of liver cancer among AAs; indeed, while the cancer risk among those without diabetes was twice as high among AAs than EAs (HR = 2.0, 95% CI = 1.4-2.9), no excess in AAs was observed among those with diabetes (HR = 0.7, 95% CI = 0.4-1.1). CONCLUSION: While liver cancer risk in general is greater in AAs than EAs and diabetes increases this risk in both racial/ethnic groups, diabetes appears to impact liver cancer to a much greater extent among EAs. The findings raise the possibility of racially different mechanisms and impacts of diabetes on this often fatal cancer among AAs and EAs.

Differences in Endothelin B Receptor Isoforms Expression and Function in Breast Cancer Cells.

The endothelins and their receptors are best known for their regulation of the vascular system. Their widespread expression in epithelial cells and their overexpression in some tumors has prompted investigation into their ability to regulate cancer progression. In this study, we assessed the mRNA expression of the major endothelin B receptor gene (EDNRB) isoforms and found differences in both mRNA and protein expression in normal breast cells and breast cancer cell lines. Knocking down the EDNRB gene in breast cancer cells altered invasiveness toward endothelin 3 (ET3), and we observed EDNRB isoform-specific regulation of breast cancer cell invasion and cell signaling, as well as isoform- and subtype-specific differences in breast cancer patient survival. The results reported in this study emphasize the importance of the endothelin B receptor in breast cancer. To our knowledge, this study is the first to clarify the differential expression and roles of specific EDNRB isoforms in breast cancer.

A Comparison of Isolated Lumbar Extension Strength Between Healthy Asymptomatic Participants and Chronic Low Back Pain Participants Without Previous Lumbar Spine Surgery.

STUDY DESIGN: Cross-sectional case-control study. OBJECTIVE: To compare isolated lumbar extension strength between healthy asymptomatic participants and participants with chronic low back pain (CLBP), while controlling for previous lumbar spine surgery. SUMMARY OF BACKGROUND DATA: Deconditioning of the lumbar musculature is common in those with previous lumbar surgery, resulting in decreased strength and endurance. Evidence is required to support whether this is the case for participants with CLBP yet no previous surgery compared with asymptomatic participants. METHODS: Forty-two healthy (25 males and 17 females) asymptomatic participants, and 53 participants with non-specific CLBP (30 males and 23 females) aged between 19 and 76 years were recruited. Maximal isometric isolated lumbar extension (ILEX) strength was examined. RESULTS: A Mann-Whitney U test indicated that ILEX strength was significantly greater in the asymptomatic group compared with the CLBP group (Z = 1441.00, P = 0.014). Post-hoc effect size was calculated to be d = 0.56, showing a moderate effect. CONCLUSION: These results indicate that ILEX weakness and lumbar extensor deconditioning is present independent of surgery and may be a factor involved in CLBP. As such, lumbar extensor deconditioning would appear to be a reasonable target for interventions in CLBP. LEVEL OF EVIDENCE: 3.

Associations between Trunk Extension Endurance and Isolated Lumbar Extension Strength in Both Asymptomatic Participants and Those with Chronic Low Back Pain.

BACKGROUND: Strength and endurance tests are important for both clinical practice and research due to the key role they play in musculoskeletal function. In particular, deconditioning of the lumbar extensor musculature has been associated with low back pain (LBP). Due to the relationship between strength and absolute endurance, it is possible that trunk extension (TEX) endurance tests could provide a proxy measure of isolated lumbar extension (ILEX) strength and thus represent a simple, practical alternative to ILEX measurements. Though, the comparability of TEX endurance and ILEX strength is presently unclear and so the aim of the present study was to examine this relationship. METHODS: Thirty eight healthy participants and nineteen participants with non-specific chronic LBP and no previous lumbar surgery participated in this cross-sectional study design. TEX endurance was measured using the Biering-Sorensen test. A maximal ILEX strength test was performed on the MedX lumbar-extension machine. RESULTS: A Pearson's correlation revealed no relationship between TEX endurance and ILEX strength in the combined group (r = 0.035, p = 0.793), the chronic LBP group (r = 0.120, p = 0.623) or the asymptomatic group (r = -0.060, p = 0.720). CONCLUSIONS: The results suggest that TEX is not a good indicator of ILEX and cannot be used to infer results regarding ILEX strength. However, a combination of TEX and ILEX interpreted together likely offers the greatest and most comprehensive information regarding lumbo-pelvic function during extension.

Prostate-specific membrane antigen (PSMA)-mediated laminin proteolysis generates a pro-angiogenic peptide.

Prostate-specific membrane antigen (PSMA) is a membrane-bound glutamate carboxypeptidase expressed in a number of tissues. PSMA participates in various biological functions depending on the substrate available in the particular tissue; in the brain, PSMA cleaves the abundant neuropeptide N-acetyl-aspartyl-glutamate to regulate release of key neurotransmitters, while intestinal PSMA cleaves polyglutamated peptides to supply dietary folate. PSMA expression is also progressively upregulated in prostate cancer where it correlates with tumor progression as well as in tumor vasculature, where it regulates angiogenesis. The previous research determined that PSMA cleavage of small peptides generated via matrix metalloprotease-mediated proteolysis of the extracellular matrix protein laminin potently activated endothelial cells, integrin signaling and angiogenesis, although the specific peptide substrates were not identified. Herein, using enzymatic analyses and LC/MS, we unequivocally demonstrate that several laminin-derived peptides containing carboxy-terminal glutamate moieties (LQE, IEE, LNE) are bona fide substrates for PSMA. Subsequently, the peptide products were tested for their effects on angiogenesis in various models. We report that LQ, the dipeptide product of PSMA cleavage of LQE, efficiently activates endothelial cells in vitro and enhances angiogenesis in vivo. Importantly, LQE is not cleaved by an inactive PSMA enzyme containing an active site mutation (E424S). Endothelial cell activation by LQ was dependent on integrin beta-1-induced activation of focal adhesion kinase. These results characterize a novel PSMA substrate, provide a functional rationale for the upregulation of PSMA in cancer cells and tumor vasculature and suggest that inhibition of PSMA could lead to the development of new angiogenic therapies.

Prostate specific membrane antigen produces pro-angiogenic laminin peptides downstream of matrix metalloprotease-2.

Prostate specific membrane antigen (PSMA) is a pro-angiogenic cell-surface protease that we previously demonstrated regulates blood vessel formation in a laminin and integrin ß1-dependent manner. Here, we examine the principal mechanism of PSMA activation of integrin ß1. We show that digesting laminin sequentially with recombinant matrix metalloprotease-2 (MMP-2) and PSMA generates small peptides that enhance endothelial cell adhesion and migration in vitro. We also provide evidence that these laminin peptides activate adhesion via integrin α6ß1 and focal adhesion kinase. Using an in vivo Matrigel implant assay, we show that these MMP/PSMA-derived laminin peptides also increase angiogenesis in vivo. Together, our results reveal a novel mechanism of PSMA activation of angiogenesis by processing laminin downstream of MMP-2.

CD13/APN regulates endothelial invasion and filopodia formation.

CD13/aminopeptidase N is a transmembrane peptidase that is induced in the vasculature of solid tumors and is a potent angiogenic regulator. Here, we demonstrate that CD13 controls endothelial cell invasion in response to the serum peptide bradykinin by facilitating signal transduction at the level of the plasma membrane. Inhibition of CD13 abrogates bradykinin B(2) receptor internalization, leading to the attenuation of downstream events such as bradykinin-induced activation of Cdc42 and filopodia formation, and thus affects endothelial cell motility. Investigation into mechanisms underlying this block led us to focus on B(2)R internalization via membrane-dependent mechanisms. Membrane disruption by depletion of cholesterol or trypsinization halts B(2)R internalization, invasion, and filopodia formation, which can be recovered with addition of cholesterol. However, this functional recovery is severely impaired in the presence of CD13 antagonists, and the distribution of membrane proteins is disordered in treated cells, suggesting a role for CD13 in plasma membrane protein organization. Finally, exogenous expression of wild-type but not mutant CD13 further alters protein distribution, suggesting peptidase activity is required for CD13's regulatory activity. Therefore, CD13 functions as a novel modulator of signal transduction and cell motility via its influence on specific plasma membrane organization, thus regulating angiogenesis.

Prostate-specific membrane antigen regulates angiogenesis by modulating integrin signal transduction.

The transmembrane peptidase prostate-specific membrane antigen (PSMA) is universally upregulated in the vasculature of solid tumors, but its functional role in tumor angiogenesis has not been investigated. Here we show that angiogenesis is severely impaired in PSMA-null animals and that this angiogenic defect occurs at the level of endothelial cell invasion through the extracellular matrix barrier. Because proteolytic degradation of the extracellular matrix is a critical component of endothelial invasion in angiogenesis, it is logical to assume that PSMA participates in matrix degradation. However, we demonstrate a novel and more complex role for PSMA in angiogenesis, where it is a principal component of a regulatory loop that is tightly modulating laminin-specific integrin signaling and GTPase-dependent, p21-activated kinase 1 (PAK-1) activity. We show that PSMA inhibition, knockdown, or deficiency decreases endothelial cell invasion in vitro via integrin and PAK, thus abrogating angiogenesis. Interestingly, the neutralization of beta(1) or the inactivation of PAK increases PSMA activity, suggesting that they negatively regulate PSMA. This negative regulation is mediated by the cytoskeleton as the disruption of interactions between the PSMA cytoplasmic tail and the anchor protein filamin A decreases PSMA activity, integrin function, and PAK activation. Finally, the inhibition of PAK activation enhances the PSMA/filamin A interaction and, thus, boosts PSMA activity. These data imply that PSMA participates in an autoregulatory loop, wherein active PSMA facilitates integrin signaling and PAK activation, leading to both productive invasion and downregulation of integrin beta(1) signaling via reduced PSMA activity. Therefore, we have identified a novel role for PSMA as a true molecular interface, integrating both extracellular and intracellular signals during angiogenesis.

Role of prostaglandin E2-dependent angiogenic switch in cyclooxygenase 2-induced breast cancer progression.

Overexpression of human cyclooxygenase 2 (COX-2) in the mammary glands of transgenic mice induces tissue-specific tumorigenic transformation. However, the molecular mechanisms involved are not yet defined. Here we show that COX-2 expressed in the epithelial cell compartment regulates angiogenesis in the stromal tissues of the mammary gland. Microvessel density increased before visible tumor growth and exponentially during tumor progression. Inhibition of prostanoid synthesis with indomethacin strongly decreased microvessel density and inhibited tumor progression. Up-regulation of angiogenic regulatory genes in COX-2 transgenic mammary tissue was also potently inhibited by indomethacin treatment, suggesting that prostanoids released from COX-2-expressing mammary epithelial cells induce angiogenesis. G protein-coupled receptors for the major product, prostaglandin E(2) (PGE(2)) EP(1-4), are expressed during mammary gland development, and EP(1,2,4) receptors were up-regulated in tumor tissue. PGE(2) stimulated the expression angiogenic regulatory genes in mammary tumor cells isolated from COX-2 transgenic mice. Such cells are tumorigenic in nude mice; however, treatment with Celecoxib, a COX-2-specific inhibitor, reduced tumor growth and microvessel density. These results define COX-2-derived PGE(2) as a potent inducer of angiogenic switch during mammary cancer progression.