Ghrelin attenuates cAMP-PKA signaling to evoke insulinostatic cascade in islet β-cells

OBJECTIVE

Ghrelin reportedly restricts insulin release in islet β-cells via the Gα_i2 subtype of G-proteins and thereby regulates glucose homeostasis. This study explored whether ghrelin regulates cAMP signaling and whether this regulation induces insulinostatic cascade in islet β-cells.

RESEARCH DESIGN AND METHODS

Insulin release was measured in rat perfused pancreas and isolated islets and cAMP production in isolated islets. Cytosolic cAMP concentrations ([cAMP]_i) were monitored in mouse MIN6 cells using evanescent-wave fluorescence imaging. In rat single β-cells, cytosolic protein kinase-A activity ([PKA]_i) and Ca²⁺ concentration ([Ca²⁺]_i) were measured by DR-II and fura-2 microfluorometry, respectively, and whole cell currents by patch-clamp technique.

RESULTS

Ghrelin suppressed glucose (8.3 mmol/L)-induced insulin release in rat perfused pancreas and isolated islets, and these effects of ghrelin were blunted in the presence of cAMP analogs or adenylate cyclase inhibitor. Glucose-induced cAMP production in isolated islets was attenuated by ghrelin and enhanced by ghrelin receptor antagonist and anti-ghrelin antiserum, which counteract endogenous islet-derived ghrelin. Ghrelin inhibited the glucose-induced [cAMP]_i elevation and [PKA]_i activation in MIN6 and rat β-cells, respectively. Furthermore, ghrelin potentiated voltage-dependent K⁺ (Kv) channel currents without altering Ca²⁺ channel currents and attenuated glucose-induced [Ca²⁺]_i increases in rat β-cells in a PKA-dependent manner.

CONCLUSIONS

Ghrelin directly interacts with islet β-cells to attenuate glucose-induced cAMP production and PKA activation, which lead to activation of Kv channels and suppression of glucose-induced [Ca²⁺]_i increase and insulin release.Ghrelin, an acylated 28-amino acid peptide, is the endogenous ligand for the growth hormone secretagogue receptor (GHS-R) (1,2). Ghrelin is produced predominantly in the stomach and stimulates growth hormone release and feeding and exhibits positive cardiovascular effects, suggesting its possible clinical application (3). Ghrelin and GHS-R are located in the pancreatic islets (4–6). Furthermore, ghrelin O-acyltransferase (GOAT), which has been identified as the enzyme that promotes the acylation of the third serine residue of ghrelin, is highly expressed in the pancreatic islets (7–9). Administration of ghrelin at 10⁻⁹–10⁻⁸ mol/L, the concentrations higher than the circulating levels of 10⁻¹⁰–10⁻⁹ mol/L, attenuates insulin release and deteriorates glucose tolerance in rodents and humans, whereas desacyl ghrelin has no effects (5,10,11). This effective concentration of ghrelin that is approximately one log order higher than the circulating level is considered physiological in the pancreatic islets for the following reasons: 1) ghrelin is produced in the pancreatic islets (5), and the ghrelin level in the pancreatic vein is one log order higher than that in the pancreatic artery (12), indicative of release of ghrelin from the pancreas; 2) ghrelin immunoneutralization and GHS-R antagonists augment glucose-induced insulin release from perfused pancreas and isolated islets (5,12); and 3) ghrelin knockout mice display enhanced glucose-induced insulin release from isolated islets without altering islet density and size, insulin content, or insulin mRNA levels, indicating increased secretory activity in the knockout mouse islets (12). Furthermore, glucose intolerance in high-fat diet–induced obese (DIO) mice is prevented in the ghrelin knockout mice as a result of enhanced insulin secretory response to glucose (12). These findings suggest that the islet-derived ghrelin regulates insulin release in a paracrine and/or autocrine manner and that manipulation of the ghrelin action could provide a novel tool to optimize insulin release (13,14).It is currently thought that GHS-R is coupled primarily to G₁₁-phospholipase C signaling (2). Intriguingly, our previous data indicated that the insulinostatic ghrelin signaling is produced via pertussis toxin (PTX)-sensitive G-protein Gα_i2 in β-cells; ghrelin PTX-sensitively activates voltage-dependent K⁺ (Kv) channels, attenuates membrane excitability, and suppresses glucose-induced Ca²⁺ concentration ([Ca²⁺]_i) increases in β-cells to attenuate insulin release (15). However, the mechanism that links GHS-R and Gα_i2 to these activities in β-cells remains to be clarified. It is known that PTX-sensitive G_i-proteins inhibit adenylate cyclase, which produces cyclic AMP in the cells. In pancreatic β-cells, intracellular cAMP signals are generated by nutrient secretagogues and play a critical role in regulating insulin secretion (16–18). However, implication of cAMP signaling in the insulinostatic function of ghrelin has been unclear. In this study, we aimed to clarify whether ghrelin regulates cAMP pathway in islet β-cells and whether this regulation leads to insulinostatic cascade in islet β-cells. We here show a novel signaling mechanism for ghrelin that operates in islet β-cells; GHS-R–mediated attenuation of cAMP and protein kinase-A (PKA) signaling leads to activation of Kv channels and suppression of glucose-induced [Ca²⁺]_i increase and insulin release.     

Connective Tissue Growth Factor Modulates Adult β-Cell Maturity and Proliferation to Promote β-Cell Regeneration in Mice

Stimulation of endogenous β-cell expansion could facilitate regeneration in patients with diabetes. In mice, connective tissue growth factor (CTGF) is expressed in embryonic β-cells and in adult β-cells during periods of expansion. We discovered that in embryos CTGF is necessary for β-cell proliferation, and increased CTGF in β-cells promotes proliferation of immature (MafA⁻) insulin-positive cells. CTGF overexpression, under nonstimulatory conditions, does not increase adult β-cell proliferation. In this study, we tested the ability of CTGF to promote β-cell proliferation and regeneration after partial β-cell destruction. β-Cell mass reaches 50% recovery after 4 weeks of CTGF treatment, primarily via increased β-cell proliferation, which is enhanced as early as 2 days of treatment. CTGF treatment increases the number of immature β-cells but promotes proliferation of both mature and immature β-cells. A shortened β-cell replication refractory period is also observed. CTGF treatment upregulates positive cell-cycle regulators and factors involved in β-cell proliferation, including hepatocyte growth factor, serotonin synthesis, and integrin β1. Ex vivo treatment of whole islets with recombinant human CTGF induces β-cell replication and gene expression changes consistent with those observed in vivo, demonstrating that CTGF acts directly on islets to promote β-cell replication. Thus, CTGF can induce replication of adult mouse β-cells given a permissive microenvironment.     

Pharmacogenomics of β-adrenergic receptor physiology and response to β-blockade

Myocardial β-adrenergic receptors (βARs) are important in altering heart rate, inotropic state, and myocardial relaxation (lusitropy). The β1AR and β2AR stimulation increases cyclic adenosine monophosphate concentration with the net result of myocyte contraction, whereas β3AR stimulation results in decreased inotropy. Downregulation of β1ARs in heart failure, as well as an increased β3AR activity and density, lead to decreased cyclic adenosine monophosphate production and reduced inotropy. The βAR antagonists are commonly used in patients with coronary artery disease and heart failure; however, perioperative use of βAR antagonists is controversial. Individual patient's response to beta-blocker therapy is an area of intensive research, and apart from pharmacokinetics, pharmacodynamics, and ethnic differences, genetic alterations have become more important in the last 20 years. The most common genetic variants in humans are single nucleotide polymorphisms (SNPs). There are 2 clinically relevant SNPs for the β1AR (Ser49Gly, Arg389Gly), 3 for the β2AR (Arg16Gly, Gln27Glu, Thr164Ile), and 1 for the β3AR (Trp64Arg). Although results are somewhat controversial, generally large datasets have the potential to show a relationship between βAR SNPs and outcomes such as development and progression of heart failure, coronary artery disease, vascular reactivity, hypertension, asthma, obesity, and diabetes. Although βAR SNPs may not directly cause disease, they appear to be risk factors for, and modifiers of, disease and the response to stress and drugs. In the perioperative setting, this has specifically been demonstrated for the Arg389Gly β1AR polymorphism with which patients with the Gly variant had a higher incidence of adverse perioperative events. Knowing that genetic variants play an important role, perioperative medicine will likely change from simple therapeutic intervention to a more personalized way of adrenergic receptor modulation.     

Modulation of β-adrenergic receptors in the ventromedial hypothalamus influences counterregulatory responses to hypoglycemia

OBJECTIVE

Norepinephrine is locally released into the ventromedial hypothalamus (VMH), a key brain glucose-sensing region in the response to hypoglycemia. As a result, this neurotransmitter may play a role in modulating counterregulatory responses. This study examines whether norepinephrine acts to promote glucose counterregulation via specific VMH β-adrenergic receptors (BAR).

RESEARCH DESIGN AND METHODS

Awake male Sprague-Dawley rats received, via implanted guide cannulae, bilateral VMH microinjections of 1) artificial extracellular fluid, 2) B2AR agonist, or 3) B2AR antagonist. Subsequently, a hyperinsulinemic-hypoglycemic clamp study was performed. The same protocol was also used to assess the effect of VMH delivery of a selective B1AR or B3AR antagonist.

RESULTS

Despite similar insulin and glucose concentrations during the clamp, activation of B2AR in the VMH significantly lowered by 32% (P < 0.01), whereas VMH B2AR blockade raised by 27% exogenous glucose requirements during hypoglycemia (P < 0.05) compared with the control study. These changes were associated with alternations in counterregulatory hormone release. Epinephrine responses throughout hypoglycemia were significantly increased by 50% when the B2AR agonist was delivered to the VMH (P < 0.01) and suppressed by 32% with the B2AR antagonist (P < 0.05). The glucagon response was also increased by B2AR activation by 63% (P < 0.01). Neither blockade of VMH B1AR nor B3AR suppressed counterregulatory responses to hypoglycemia. Indeed, the B1AR antagonist increased rather than decreased epinephrine release (P < 0.05).

CONCLUSIONS

Local catecholamine release into the VMH enhances counterregulatory responses to hypoglycemia via stimulation of B2AR. These observations suggest that B2AR agonists might have therapeutic benefit in diabetic patients with defective glucose counterregulation.Lowering glucose toward normal in patients with type 1 diabetes is well documented to reduce long-term complications (1). In clinical practice, however, intensified insulin treatment is often limited by the increased risk of severe hypoglycemia (2). In people without diabetes, a fall in blood glucose is rapidly detected by glucose-sensing neurons in the brain and periphery, and a series of compensatory responses occur to prevent or limit hypoglycemia and to restore euglycemia. Specifically, the activation of counterregulatory hormone release (e.g., glucagon and epinephrine) and the sympathetic nervous system (norepinephrine) promote endogenous glucose production, reduce tissue utilization of glucose, and generate typical warning symptoms. These protective responses against hypoglycemia are disrupted in most patients with type 1 diabetes receiving intensive insulin therapy (3,4). As a result, they display impaired neurohumoral responses to hypoglycemia and, in some cases, the loss of symptomatic awareness of hypoglycemia. The molecular mechanism(s) underlying this phenomenon are not fully understood.Detection of hypoglycemia by glucose-sensing cells/neurons peripherally (5) and centrally (6) is critical in the defense against hypoglycemia and the prevention of brain injury. One brain region in particular, the ventromedial hypothalamus (VMH), appears to play a key role in hypoglycemia sensing (7). It contains glucose-excited and glucose-inhibited neurons that detect changes in ambient glucose levels and then alter their firing rate accordingly (8). The VMH contains glutamatergic and γ-aminobutyric acid (GABA)ergic innervations, both of which have been shown to have an effect on counterregulatory responses to hypoglycemia (9,10). In addition, monoamine neurotransmitters, such as norepinephrine, are also released into the VMH and appear to regulate VMH function during hypoglycemia. It has been reported that norepinephrine has been reported to stimulate glutamatergic neurotransmission in mechanically dissociated rat VMH neurons and that this effect is mediated via activation of β₂-adrenergic receptors (B2AR) (11). The loss of function of glutamatergic neurons in the VMH region, however, suppresses glucose counterregulation in mice (10). In addition, a rise in norepinephrine concentrations in VMH interstitial fluid has been reported during acute hypoglycemia (12), and this rise is prevented when glucose is perfused into the VMH and systemic hypoglycemia is maintained (13). Although local norepinephrine release into the VMH appears to be altered during hypoglycemia, the neuronal projection circuits coordinating this response are not fully understood. It has been suggested that the brainstem and other hypothalamic regions are important components of a glucose-sensing network coordinating defenses against hypoglycemic stress (14,15).The current study was undertaken to assess the mechanisms by which the local release of catecholamines might act within the VMH to influence the magnitude of the counterregulatory response to hypoglycemia. Our data suggest that norepinephrine modulates VMH neurons during hypoglycemia at least in part through B2AR.     

Loss of HGF/c-Met signaling in pancreatic β-cells leads to incomplete maternal β-cell adaptation and gestational diabetes mellitus

Hepatocyte growth factor (HGF) is a mitogen and insulinotropic agent for the β-cell. However, whether HGF/c-Met has a role in maternal β-cell adaptation during pregnancy is unknown. To address this issue, we characterized glucose and β-cell homeostasis in pregnant mice lacking c-Met in the pancreas (PancMet KO mice). Circulating HGF and islet c-Met and HGF expression were increased in pregnant mice. Importantly, PancMet KO mice displayed decreased β-cell replication and increased β-cell apoptosis at gestational day (GD)15. The decreased β-cell replication was associated with reductions in islet prolactin receptor levels, STAT5 nuclear localization and forkhead box M1 mRNA, and upregulation of p27. Furthermore, PancMet KO mouse β-cells were more sensitive to dexamethasone-induced cytotoxicity, whereas HGF protected human β-cells against dexamethasone in vitro. These detrimental alterations in β-cell proliferation and death led to incomplete maternal β-cell mass expansion in PancMet KO mice at GD19 and early postpartum periods. The decreased β-cell mass was accompanied by increased blood glucose, decreased plasma insulin, and impaired glucose tolerance. PancMet KO mouse islets failed to upregulate GLUT2 and pancreatic duodenal homeobox-1 mRNA, insulin content, and glucose-stimulated insulin secretion during gestation. These studies indicate that HGF/c-Met signaling is essential for maternal β-cell adaptation during pregnancy and that its absence/attenuation leads to gestational diabetes mellitus.     

Post-surgical wound infections involving Enterobacteriaceae with reduced susceptibility to β-lactams in two Portuguese hospitals

The post-surgical period is often critical for infection acquisition. The combination of patient injury and environmental exposure through breached skin add risk to pre-existing conditions such as drug or depressed immunity. Several factors such as the period of hospital staying after surgery, base disease, age, immune system condition, hygiene policies, careless prophylactic drug administration and physical conditions of the healthcare centre may contribute to the acquisition of a nosocomial infection. A purulent wound can become complicated whenever antimicrobial therapy becomes compromised. In this pilot study, we analysed Enterobacteriaceae strains, the most significant gram-negative rods that may occur in post-surgical skin and soft tissue infections (SSTI) presenting reduced β-lactam susceptibility and those presenting extended-spectrum β-lactamases (ESBL). There is little information in our country regarding the relationship between β-lactam susceptibility, ESBL and development of resistant strains of microorganisms in SSTI. Our main results indicate Escherichia coli and Klebsiella spp. are among the most frequent enterobacteria (46% and 30% respectively) with ESBL production in 72% of Enterobacteriaceae isolates from SSTI. Moreover, coinfection occurred extensively, mainly with Pseudomonas aeruginosa and Methicillin-resistant Staphylococcus aureus (18% and 13%, respectively). These results suggest future research to explore if and how these associations are involved in the development of antibiotic resistance.     

Circulating β2 Microglobulin in Relation to Bone Metabolism: Implications for Bone Loss with Aging

The aim of this cross-sectional study was to evaluate the relationships between circulating β₂ microglobulin (β₂ m) and bone mineral density (BMD), parameters of bone remodeling, vitamin D metabolites, parathyroid hormone (PTH), estradiol levels, and age in a group of 165 clinically healthy or osteoporotic, but otherwise normal untreated women. In this group of women, systemic β₂ m correlated with BMD (g/cm²) levels for total hip and Ward's triangle (r =−0.298, P < 0.0001; and r =−0.299, P < 0.0001, respectively), but only at the borderline level with BMD at the spine (r =−0.145, P= 0.0604). Serum β₂ microglobulin markedly correlated with age (r = 0.512, P= 0.0001). β₂ m levels correlated with indices of bone remodeling, as well as with serum creatinine and estradiol levels. However, after stratification of all analyses by age, body mass index, and serum 25OHD₃, 1,25(OH)₂D₃, PTH, or estradiol levels (using standard multiple regression and stepwise forward regression models), only 25OHD₃ was found to be an independent predictor of BMD at the hip, including Ward's triangle, as estradiol of BMD at the spine. On the other hand, β₂ m was not associated with BMD at any of the measured regions. Also, no association was found between serum PTH and BMD values. Therefore, systemic β₂ m seems to be an indicator of bone remodeling in the course of natural skeletal aging rather than a variable independently predicting bone loss. Received: 21 July 1998 / Accepted: 10 June 1999     

Improvement in β-Cell Secretory Capacity After Human Islet Transplantation According to the CIT07 Protocol

The Clinical Islet Transplantation 07 (CIT07) protocol uses antithymocyte globulin and etanercept induction, islet culture, heparinization, and intensive insulin therapy with the same low-dose tacrolimus and sirolimus maintenance immunosuppression as in the Edmonton protocol. To determine whether CIT07 improves engrafted islet β-cell mass, our center measured β-cell secretory capacity from glucose-potentiated arginine tests at days 75 and 365 after transplantation and compared those results with the results previously achieved by our group using the Edmonton protocol and normal subjects. All subjects were insulin free, with CIT07 subjects receiving fewer islet equivalents from a median of one donor compared with two donors for Edmonton protocol subjects. The acute insulin response to glucose-potentiated arginine (AIR_pot) was greater in the CIT07 protocol than in the Edmonton protocol and was less in both cohorts than in normal subjects, with similar findings for C-peptide. The CIT07 subjects who completed reassessment at day 365 exhibited increasing AIR_pot by trend relative to that of day 75. These data indicate that engrafted islet β-cell mass is markedly improved with the CIT07 protocol, especially given more frequent use of single islet donors. Although several peritransplant differences may have each contributed to this improvement, the lack of deterioration in β-cell secretory capacity over time in the CIT07 protocol suggests that low-dose tacrolimus and sirolimus are not toxic to islets.Islet transplantation is an emerging cell therapy for the treatment of type 1 diabetes (1), particularly for those patients experiencing severe problems with hypoglycemia or who have already received a kidney transplant. The Edmonton protocol for islet transplantation established that glucocorticoid-free immunosuppression together with a subsequent islet infusion from a second donor pancreas could reproducibly render the recipient insulin independent (2). A multicenter trial using this approach resulted in insulin independence in 60% of recipients, although the majority of these patients returned to insulin therapy by 2 years posttransplant (3). Nonetheless, 80% of recipients maintained islet graft function as indicated by a reduction in insulin requirements and C-peptide production for the 2 years of follow-up (3). Using the Edmonton protocol, we previously reported that despite receiving almost 1 million islets, insulin-independent recipients had a β-cell secretory capacity only ∼25% that of normal (4). The lower functional islet β-cell mass for the numbers transplanted suggested early loss of transplanted islets before engraftment that might be attributable to nonspecific inflammatory and thrombotic mechanisms (5). This reduced engrafted islet β-cell mass is just at the margin of what is required to avoid hyperglycemia (6); therefore, it likely explains the eventual return to insulin therapy experienced by the majority of recipients treated by the Edmonton protocol.More recent induction immunosuppression protocols introduced by the University of Minnesota have incorporated peritransplant anti-inflammatory and antithrombotic therapy with similar low-dose calcineurin inhibitor and mammalian target of rapamycin (mTOR) inhibitor maintenance therapy as in the Edmonton protocol, with improved rates of insulin independence occurring more frequently with islets isolated from a single donor (7) and being sustained for a longer duration (8,9). The multicenter Clinical Islet Transplantation 07 (CIT07) protocol uses components of the Minnesota approach, including the polyclonal T-cell–depleting antibody rabbit antithymocyte globulin (rATG) and the tumor necrosis factor-α (TNF-α) inhibitor etanercept at induction, an islet culture period of 36–72 h, full heparinization peritransplant, pentoxifylline and anticoagulation for 1 week (7), intensive insulin therapy for 2 months, and the same low-dose tacrolimus and sirolimus (formerly called rapamycin) for maintenance immunosuppression as in the Edmonton protocol (10). We sought to determine whether the peritransplant changes in the CIT07 protocol improved engrafted islet β-cell mass by measuring β-cell secretory capacity from glucose-potentiated arginine tests in CIT07 subjects who underwent transplantation at the University of Pennsylvania at 75 and 365 days after their final islet infusion, and comparing their results with those previously achieved at our center with the Edmonton protocol.     

Reduced insulin exocytosis in human pancreatic β-cells with gene variants linked to type 2 diabetes

The majority of genetic risk variants for type 2 diabetes (T2D) affect insulin secretion, but the mechanisms through which they influence pancreatic islet function remain largely unknown. We functionally characterized human islets to determine secretory, biophysical, and ultrastructural features in relation to genetic risk profiles in diabetic and nondiabetic donors. Islets from donors with T2D exhibited impaired insulin secretion, which was more pronounced in lean than obese diabetic donors. We assessed the impact of 14 disease susceptibility variants on measures of glucose sensing, exocytosis, and structure. Variants near TCF7L2 and ADRA2A were associated with reduced glucose-induced insulin secretion, whereas susceptibility variants near ADRA2A, KCNJ11, KCNQ1, and TCF7L2 were associated with reduced depolarization-evoked insulin exocytosis. KCNQ1, ADRA2A, KCNJ11, HHEX/IDE, and SLC2A2 variants affected granule docking. We combined our results to create a novel genetic risk score for β-cell dysfunction that includes aberrant granule docking, decreased Ca(2+) sensitivity of exocytosis, and reduced insulin release. Individuals with a high risk score displayed an impaired response to intravenous glucose and deteriorating insulin secretion over time. Our results underscore the importance of defects in β-cell exocytosis in T2D and demonstrate the potential of cellular phenotypic characterization in the elucidation of complex genetic disorders.     

Hypoparathyroidism in transfusion-dependent patients with β-thalassemia

Hypoparathyroidism is thought to be a rare consequence of iron overload seen in β-thalassemic transfused patients. This study was conducted to determine the prevalence of hypoparathyroidism in a large number of β-thalassemic patients, and its potential correlation with the presence of other endocrinopathies caused by iron overload. Serum and urine biochemical parameters were measured in 243 thalassemic patients (136 females and 107 males) in order to determine the prevalence of hypoparathyroidism and evaluate bone turnover. The patients were divided into two groups according to the presence of hypoparathyroidism. We compared the prevalence of other endocrinopathies and disease complications in the two groups. Hypoparathyroidism was detected in 13.5% of the patients (33 subjects; 17 males and 16 females). Serum-intact parathyroid hormone, and total and ionized calcium were significantly lower, while phosphorus was significantly higher in thalassemic patients with hypoparathyroidism. The reduction in BMD was more prominent in normal thalassemic patients (Z score = −2.246 ± 0.97) compared with those with hypoparathyroidism (Z score = −1.975 ± 0.89), although the difference was not statistically significant. Disturbed glucose metabolism was more common in patients with hypoparathyroidism (P < 0.05). In addition, heart dysfunction was statistically more frequent in this group (odds ratio = 2.51, P < 0.05). Hypoparathyroidism is a not infrequently observed complication in thalassemic patients. Since the concentration of ferritin is not a valuable tool in the prediction of the development of hypoparathyroidism, parathyroid function should be tested periodically, particularly when other iron overload-associated complications occur.     

Mechanisms of renal disease in β-thalassemia

Although advances in the care of patients with β-thalassemia translate into better patient survival, this success has allowed previously unrecognized complications to emerge, including several renal abnormalities. Clinical studies continue to show that mild tubular dysfunction and abnormalities in GFR are common in patients with β-thalassemia. Chronic anemia and iron overload are believed to lie behind these abnormalities. Nonprogressive increases in levels of serum creatinine have also been observed after exposure to some iron chelators. Longitudinal studies are needed to understand the true burden of renal dysfunction in patients with β-thalassemia.     

Expression of P-aPKC-ι, E-Cadherin, and β-Catenin Related to Invasion and Metastasis in Hepatocellular Carcinoma

Objectives  Atypical protein kinase C iota (aPKC-ι) and its associated intracellular molecules, E-cadherin and β-catenin, are important for cell polarization in tumorigenesis and progression. Expression of aPKC-ι, P-aPKC-ι (activated aPKC-ι), E-cadherin, and β-catenin in hepatocellular carcinoma (HCC) was measured, and correlation with clinicopathological characteristics of HCC was analyzed. Methods  Paraffin-embedded tumor tissue was obtained from patients with HCC after resection without preoperative radiotherapy or chemotherapy. Gene expression was detected by polymerase chain reaction (PCR), and protein expression was detected by immunohistochemistry and Western blot analysis. Expressions of aPKC-ι, P-aPKC-ι, E-cadherin, and β-catenin were analyzed with relation to the clinicopathological data. Results  The gene and protein expression of aPKC-ι are obviously higher in HCC tissues than that in peritumoral tissues and normal tissues by semiquantitative PCR and immunohistochemistry methods. Accumulation of aPKC-ι in HCC cytoplasm and nucleolus inhibited the later formation of belt-like adherens junctions (AJs) and/or tight junctions (TJs) in cell–cell contact. E-cadherin was reduced and accumulation of cytoplasm β-catenin was increased in HCC. The expression of aPKC-ι was closely related to pathological differentiation, tumor size, invasion, and metastasis of HCC. Conclusion  Accumulation of cytoplasm aPKC-ι may reflect pathological differentiation, invasion, and metastasis potential of HCC. In this regard, our study on HCC revealed the potential usefulness of aPKC-ι, E-cadherin, and β-catenin as a prognostic marker, closely related to pathological differentiation, invasion, metastasis, and prognosis of HCC.