Heterodimerization of cholecystokinin 1 and cholecystokinin 2 receptors in gallbladder cancer: a new mechanism for carcinogenesis

PURPOSE

Cholecystokinin is present in abundance in gallbladder tissue and mediates function through two structurally related receptors, CCK1R and CCK2R. Heterodimerization of these receptors is known to impact cell growth in vitro. However, the significance of these heterodimers in gallbladder carcinogenesis is relatively unknown.

METHODS

Therefore, we evaluated the expression and the dimerization status of CCK1 and CCK2 receptors in human gallbladder carcinoma cell line (GBC-SD) and resected gallbladder tissue from normal (n = 10), cholelithiasis (n = 25) and gallbladder cancer (n = 25) by immunofluorescence/immunohistochemistry and western blot. The dimerization status of CCK1R and CCK2R was evaluated by co-immunoprecipitation. To understand the effect of heterodimerization of these receptors on growth-related signaling pathways, the expression of p-AKT, rictor, raptor and p-ERK was evaluated by western blot.

RESULTS

We demonstrated the expression and heterodimerization of CCK1 and CCK2 receptor in GBC-SD gall bladder carcinoma cell line. Knockdown of CCK1R and CCK2R in the cell line led to significant reduction in p-AKT (P = 0.005; P = 0.0001) and rictor (P < 0.001; P < 0.001) levels. In tissue samples, significantly higher expression of CCK1R and CCK2R was observed in gallbladder cancer when compared to other groups both by immunohistochemistry (P = 0.008 and P = 0.013) and western blot (P = 0.009 and P = 0.003). An increase in heterodimer formation of CCK1R with CCK2R was observed in gallbladder cancer when compared to normal and cholelithiasis tissues. No significant difference in the expression of p-AKT and p-ERK was observed between the three groups.

CONCLUSION

Our results provide the first evidence of heterodimerization of CCK1R and CCK2R in gallbladder tissue, and its association with development of gallbladder cancer. This finding has potential clinical and therapeutic significance.

Expression of Antimicrobial Peptides and Cytokines in Human Omentum Following Abdominal Surgery

Introduction

Omentum can secrete out biological agents like different growth factors, cytokines, and antimicrobial peptides. The aim of our study was to determine the expression of antimicrobial peptides and cytokines in human omentum tissue and its response to intra-abdominal infection.

Methodology

Omentum tissue was obtained from 60 patients: control (n=20) and cases (n=40). mRNA expression of antimicrobial peptides (LL-37, HBD-1, HBD-2, HNP1-3) and cytokines (TNF- α, IL-8, IL-10, IL1β) was evaluated using Real-Time PCR. Protein quantification was done by Immunoblotting and ELISA.

Results

Significantly higher expression of antimicrobial peptides (LL-37, HBD-1, HBD-2, HNP1-3) and cytokines (TNF- α, IL-8, IL-10, IL1β) was observed in cases as compared to control at both the transcriptional and translational level (p<0.0001).

Conclusion

Omentum governs a population of antimicrobial peptides with potent immunologic functions. The expression of antimicrobial peptides and cytokines is inducible and increases with the severity of infection. Omentum is thus an immunologically active and adaptable organ but its complete regulatory mechanism is still elusive.

Antibacterial spectrum of human omentum and differential expression of beta defensins

BACKGROUND

Human β defensins (hBD1 and hBD2) are cationic, cysteine-rich peptides and form an integral part of the mammalian innate immune system. hBD1 is constitutively expressed in epithelial cells, whereas hBD2 increases in response to bacterial infection. Human omentum is known for its anti-inflammatory properties and also possesses an antibacterial activity of its own. We hypothesized that antimicrobial peptides, β defensins, may govern host defense mechanism in the microbe-rich environment of the peritoneal cavity. Therefore, we analyzed the expression of hBD1 and hBD2 in omentum tissue in vivo and also studied the antibacterial activity of omentum against common pathogens.

METHODOLOGY

Omentum tissues were obtained from 30 patients (15 cases and 15 controls). Real-time polymerase chain reaction (PCR) was used to evaluate the mRNA expression of hBD1 and hBD2. Protein quantification was done using Western blotting technique. Antibacterial susceptibility was performed to check the antibacterial activity of omentum.

RESULT

Significantly higher expression of hBD2 was observed in cases compared to controls at both the transcriptional and translational levels. In comparison with an array of antibiotics, activated omentum also showed antibacterial property even at lower concentration of its extract.

CONCLUSION

Omentum directly responds to bacterial infection, which may be due to differential expression of hBD1 and hBD2 in human omental tissue. These peptides (hBD1 and hBD2) may be an ideal candidate for novel antibiotic class with a broad-spectrum activity.

Low Expression of MicroRNA335-5p Is Associated with Malignant Behavior of Gallbladder Cancer: A Clinicopathological Study

Background: MicroRNAs (miRNAs) are non-coding RNAs that regulate multiple cellular processes during cancer progression, identified to be involved in tumorgenesis of several cancers including cancers of digestive system. However its role in gallbladder inflammatory disease (GID) and gallbladder cancer (GBC) has not been well documented. The present study was aimed to investigate the clinical significance of hsa-miRNA-335-5p (miR-335) in GBC and GID. Subjects and Methods: This prospective case control study, conducted from July 1, 2014 to December 1, 2017 in Era’s Lucknow Medical College & Hospital, India, evaluated miR-335 expression by real-time polymerase chain reaction. Hundred tissue samples GID (control; n=50) and GBC (case; n=50) were studied. Relative quantification of target miR-335 expression was examined using the comparative cycle threshold method. Their expression was correlated with different clinicopathological parameters. Fishers’ exact test, Student’s t-test, and Chi-square test were used as appropriate for data analysis. Kaplan-Meier methods were used to calculate overall and disease-free survival rate. Two sided P<0.05 was considered as significant. Results: miR-335 expression was found to be significantly low in GBC lesions when compared with GID lesions (P<0.001). The low expression level of miR-335 was correlated with histological grade (P=0.007), clinical stage (P<0.001), lymph node metastasis (P<0.001) and liver metastasis (P=0.016). Reduced expression of miRNA-335 was associated with a shorter median overall survival (7 months vs. 25 months) in GBC patients (P<0.001). Conclusions: Down regulation of miR-335 is associated with the severity of the disease and thus indicate that miR-335 expression may serve as prognostic marker for GBC.

Expression and heterodimerization of Type A and B Cholecystokinin Receptors in Gallbladder cancer

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Background: Gallbladder cancer is the most common malignancy of the biliary tract and endemic in Northern India. The prognosis of gallbladder cancer remains dismal despite any treatment because of late presentation and aggressive tumor biology. Cholecystokinin (CCK) is present in abundance in gallbladder tissue and mediates function through two structurally related receptors, the type A (CCKAR) and B (CCKBR) receptors. Previously, heterodimerization of CCKAR and CCKBR receptor has been demonstrated in vitro, and was shown to bind natural agonists normally but exhibited agonist stimulated cellular signaling, promoting cell growth. In this study we examined the expression level of CCKAR and CCKBR in resected gallbladder tissue samples and also attempted to determine the dimerization status of CCKAR and CCKBR receptors in gallbladder cancer comparing them to cholelithiasis and normal gallbladder tissue. Methods: Tissue samples from resected normal gallbladder (n = 10), cholelithiasis (n = 25) and gallbladder cancer (n = 25)) were evaluated for the expression of CCKAR and CCKBR by immunohistochemistry. Determination of CCKAR and CCKBR expression was also done by western blot in representative samples from each of these tissue types while their dimerization status was evaluated by immunoprecipitation. Results: By Immunohistochemistry technique, positive CCKAR expression was observed in 80% gallbladder cancer, 84% cholelithiasis, 90% normal gallbladder, P = 0.76. However significantly higher expression of CCKBR was noted in gallbladder cancer (60%) as compared to cholelithiasis (25%) and normal gallbladder (20%), P = 0.013. We also observed progressively increasing level of expression of CCKAR and CCKBR in gallbladder cancer as compared to cholelithiasis and normal gallbladder by western blot. In addition, we also observed a higher level of heterodimer formation in gallbladder cancer compared to cholelithiasis and normal gallbladder using immunoprecipitation technique. Conclusions: Our results provide the first evidence of increasing trend of heterodimerization of CCKAR and CCKBR in gallbladder cancer which has potential clinical and therapeutic significance.

Expression and clinicopathological significance of antiapoptotis protein survivin in gallbladder cancer

BACKGROUND

Clinical significance of survivin (antiapoptosis protein) in gallbladder cancer is not yet established.

AIMS

This study was performed to assess the expression pattern of survivin in benign and malignant gallbladder lesions using immunohistochemistry (IHC), and to assess its clinicopathological significance.

SETTINGS AND DESIGN

Prospective study from July 2012 to July 2014 was performed as a part of intramural research project.

MATERIALS AND METHODS

Tissue samples from resected gallbladder for cholelithiasis (n = 27) and carcinoma gallbladder (n= 24) were evaluated for survivin expression by IHC using a scoring system. Their expression was correlated with different clinicopathological parameters.

STATISTICAL ANALYSIS

Fisher's exact test, Student's t-test, and Chi-square test were used as appropriate for data analysis. Kaplan-Meier methods were used to calculate overall and disease-free survival rates among different groups. Two-sided P< 0.05 was considered as significant.

RESULTS

Benign group (19 females, age [mean ± standard deviation [SD] 45 ± 14 years) and malignant group (20 females, age [mean ± SD] 48.9 ± 13.4 years) were comparable with respect to menopausal status, presence, size and types of stones. However, survivin expression was significantly higher (66.7%, 95% confidence interval [CI] 24-75) in gallbladder cancer than in cholelithiasis group (33%, CI 46-83), P= 0.025). Its expression did not correlate with gender, age, menopausal status, presence of gallstones or their size, number and type, tumor differentiation, and tumor stage.

CONCLUSIONS

Significantly higher expression of survivin protein in gallbladder cancer as compared to cholelithiasis group suggests its role in gallbladder carcinogenesis though it may not have prognostic value.

Polymorphism and Expression Profile of Cholecystokinin Type A Receptor in Relation to Gallstone Disease Susceptibility

In the present study, we investigated expression pattern of Cholecystokinin type A receptor (CCKAR) in relation to its commonly studied polymorphism (rs1800857, T/C) in gallstone disease (GSD) patients and controls. A total of 502 subjects (272 GSD and 230 controls) were enrolled, and genotyping was performed by evaluating restriction fragments of PstI digested DNA. For analyzing expression pattern of CCKAR in relation to polymorphism, gallbladder tissue samples from 80 subjects (GSD-55; control-25) were studied. Expression of CCKAR mRNA was evaluated by reverse transcriptase-PCR and confirmed using real-time PCR. Protein expression was evaluated by enzyme-linked immunosorbent assay. We observed significantly (p < 0.0001) lower expression of CCKAR mRNA and protein in GSD tissues as compared with control. Significantly higher frequency of A1/A1 genotype (C/T transition) (p = 0.0005) was observed for GSD as compared with control. Expression of CCKAR protein was found to be significantly lower (p < 0.0001) in A1/A1 genotype as compared with other genotypes for GSD patients. Perhaps, this is the first report providing evidence of alteration in CCKAR expression in relation to its polymorphism elucidating the molecular pathway of the disease. Additional investigations with lager sample size are needed to confirm these findings.

Expression of survivin mRNA in gallbladder cancer: a diagnostic and prognostic marker?

Survivin, an inhibitor of apoptosis, has been shown to be expressed in various malignancies. However, its role in gallbladder cancer (GBC) has not been evaluated yet. We investigated its expression in peripheral blood of patients with gallbladder diseases (gallstone disease (GSD), n = 30; GBC, n = 39) and compared with healthy controls (n = 25). Survivin expression was correlated with clinicopathological parameters, diagnosis, and prognosis of patients with GBC. Expression of survivin messenger RNA (mRNA) in blood was evaluated by real-time PCR. Significantly higher (P < 0.0001) expression of survivin mRNA was observed in GBC (2.2-fold) and GSD (1.52-fold) as compared to control. In GBC, increased survivin expression was significantly associated with higher tumor stage (stage III vs. stage II; P < 0.0001) and tumor differentiation (poor and moderate vs. well differentiated; P < 0.0001). No significant correlation was observed with any of the other clinicopathological parameters (age, gender, and presence or absence of gallstones) studied. Cutoff value of survivin mRNA relative quantification (RQ) was 1.08, with a sensitivity of 98.55 % and specificity of 100 % for the diseased group (GSD or GBC). RQ value of 1.71 differentiated GBC from GSD with a sensitivity of 89.74 % and specificity of 100 %. Increased expression of survivin was associated with a shorter median overall survival (12 vs. 18 months) in GBC patients. Differential expression of survivin in GBC suggests its possible role and association with poor prognosis. Expression of survivin in peripheral blood could be useful both in the diagnosis and prognosis of GBC.

Prognostic significance of K-ras codon 12 mutation in patients with resected gallbladder cancer

BACKGROUND

Point mutation of K-ras is associated with carcinogenesis and overall survival in various cancers. We investigated the mutational spectrum of K-ras codon 12 in resected normal and gallbladder cancer tissue samples in a Northern Indian population and correlated it with different clinicopathological parameters.

PATIENTS AND METHODS

Gallbladder tissues from normal (n = 24) and cancer patients (n = 39) were analyzed for K-ras codon 12 mutation by restriction fragment length polymorphism. Statistical analysis was carried out using the χ(2) test or Fisher's exact test. Survival was estimated using the Kaplan-Meier method, and the difference between survival curves was analyzed by the log-rank test.

RESULTS

The frequency of K-ras mutation was significantly higher (p = 0.001) in gallbladder cancer tissue samples (16/39) compared to normal samples (1/24). Patients with K-ras mutation had a significantly decreased overall survival (p = 0.003), particularly for stage II (p = 0.021) and III (p = 0.009) cancers. No significant correlation was observed with any of the other clinicopathological factors studied.

CONCLUSIONS

Gallbladder cancer has a high frequency of K-ras codon 12 mutation with poorer outcomes in resected stage II and III disease. K-ras mutational analysis has important prognostic implications that need to be investigated further.

Use of cervical ultrasonography in prediction of spontaneous preterm birth in twin gestations

OBJECTIVE

This study was undertaken to compare various ultrasonographic cervical parameters with respect to ability to predict spontaneous preterm birth in twin gestations.

STUDY DESIGN

This prospective study involved 131 women carrying twins who were longitudinally evaluated on 524 occasions between 15 and 28 weeks' gestation with transvaginal cervical ultrasonography and transfundal pressure. The following cervical parameters were obtained: funnel width and length, cervical length, percentage of funneling, and cervical index. Receiver operating characteristic curve analysis was used to determine the ultrasonographic cervical parameter evaluated at 15 to 20 weeks' gestation, 21 to 24 weeks' gestation, and 25 to 28 weeks' gestation that were best for prediction of spontaneous preterm birth at <28 weeks' gestation, <30 weeks' gestation, <32 weeks' gestation, and <34 weeks' gestation.

RESULTS

The median gestational age at delivery was 36 weeks' gestation (range, 21-41 weeks' gestation). Receiver operating characteristic curve analysis indicted that a cervical length of < or =2.0 cm, regardless of gestational age category at cervical measurement, was at least as good as other ultrasonographic cervical parameters at predicting spontaneous preterm birth. Between 15 and 20 weeks' gestation a cervical length cutoff value of < or =2.0 cm had specificities of 97%, 98%, 99%, and 100% and negative predictive values of 99%, 98%, 95%, and 89% for delivery at <28, <30, <32, and <34 weeks' gestation, respectively. The positive predictive values for delivery at <32 and <34 weeks' gestation were 80% and 100%, respectively. Between 21 and 24 weeks' gestation a cervical length of < or =2.0 cm had specificities of 84%, 84%, 85%, and 86% and negative predictive values of 99%, 99%, 94%, and 87% for delivery at <28, <30, <32, and <34 weeks' gestation, respectively. Between 25 and 28 weeks' gestation cervical length had excellent negative predictive values of 99%, 98%, 95%, and 93% for delivery at <28, <30, <32, and <34 weeks' gestation, respectively.

CONCLUSIONS

In twin gestations a cervical length of < or =2.0 cm measured between 15 and 28 weeks' gestation was at least as good as other ultrasonographic cervical parameters at predicting spontaneous preterm birth. The high specificities indicate that cervical length was better at predicting the absence than the presence of various degrees of spontaneous prematurity.

Use of cervical ultrasonography in prediction of spontaneous preterm birth in triplet gestations

OBJECTIVE

The aim of this study was to assess the role of cervical ultrasonography in the prediction of spontaneous preterm birth in triplet gestations and to compare various ultrasonographic cervical parameters with respect to predictive ability.

STUDY DESIGN

This prospective cohort study included 51 triplet gestations longitudinally evaluated between 15 and 28 weeks' gestation on 274 occasions with transvaginal cervical ultrasonography and transfundal pressure. The cervical parameters obtained were funnel width and length, cervical length, percentage of funneling, and cervical index.

RESULTS

Receiver operating characteristic curve analyses showed that cervical lengths of < or =2.5 cm and < or =2.0 cm between 15 and 24 weeks' gestation and between 25 and 28 weeks' gestation, respectively, were at least as good as other ultrasonographic cervical parameters for the prediction of spontaneous preterm birth. A cervical length of < or =2.5 cm between 15 and 20 weeks' gestation had both a specificity and a positive predictive value of 100% for delivery at <28 weeks' gestation, and the sensitivities and negative predictive values ranged from 25% to 50% and from 72% to 91%, respectively, for deliveries at <28, <30, and <32 weeks' gestation. A cervical length of < or =2.5 cm between 21 and 24 weeks' gestation had an 86% sensitivity for prediction of spontaneous delivery at <28 weeks' gestation. A cervical length of < or =2.0 cm between 25 and 28 weeks' gestation had both a sensitivity and a negative predictive value of 100% for delivery at both <28 and <30 weeks' gestation.

CONCLUSIONS

In triplet gestations cervical lengths of < or =2.5 cm between 15 and 24 weeks' gestation and < or =2.0 cm between 25 and 28 weeks' gestation were at least as good as other ultrasonographic cervical parameters for the prediction of spontaneous preterm birth.