Potential of Mac-2-binding protein glycan isomer as a new therapeutic target in pancreatic cancer

Pancreatic cancer (PC) is a challenging malignancy to treat. Mac-2-binding protein glycan isomer (M2BPGi) is a novel serum marker of liver fibrosis and hepatocellular carcinoma and is secreted by hepatic stellate and stroma cells. Serum M2BPGi levels are upregulated in PC patients. We measured the expression of M2BPGi in the serum of 27 PC patients and determined whether M2BPGi affects the malignant potential of PC cells in vitro. We also examined the effect of M2BP on PC tumor growth and gemcitabine sensitivity in vivo. Serum M2BPGi levels in PC patients were higher compared with those of healthy subjects. M2BPGi extraction in cancer-associated fibroblasts (CAFs) was higher compared with that of PC cells. M2BPGi treatment promoted the proliferation and invasion of PC cells. The suppression of galectin-3, which binds to M2BPGi, did not affect the proliferation-promoting effect of M2BPGi in PC cells. The suppression of M2BP reduced tumor growth and enhanced gemcitabine sensitivity in PC-bearing xenograft mice. CAF-derived M2BPGi promotes the proliferation and invasion of PC cells. Targeting M2BPGi may represent a new therapeutic strategy to circumvent refractory PC.

High RRN3 expression is associated with malignant characteristics and poor prognosis in pancreatic cancer

BACKGROUND

Pancreatic cancer has an extremely poor prognosis and is one of the most chemoresistant cancers. Targeting cancer cell transcriptional complexes may enhance chemotherapy effectiveness. RNA-polymerase I (Pol-I)-mediated transcription is an essential initial step for ribosome biogenesis and is related to cancer cell proliferation. RRN3 is a Pol-I-specific transcription initiation factor. In this study, we aimed to elucidate the function and clinical significance of RRN3 in pancreatic cancer.

METHODS

We performed immunohistochemical staining to detect RRN3 protein expression in 96 pancreatic cancer tissues and analyzed the relationship between RRN3 protein expression, clinicopathological factors, and cancer patient prognosis. Moreover, we evaluated RRN3 function in vitro and in vivo using proliferation, invasion, and chemosensitivity assays in PANC-1 and SW1990 cell lines, with/without depleting RRN3 expression.

RESULTS

RRN3 was mainly expressed in cancer cell nuclei. High levels of RRN3 expression were associated with Ki-67 expression and shorter overall survival. Additionally, proliferation and invasion ability were decreased when RRN3 was silenced with siRNA, compared to non-targeting siRNA-transfected cells. Chemosensitivity analysis showed that inhibition of RRN3 enhanced the sensitivity of pancreatic cancer cell lines to gemcitabine and paclitaxel. RRN3 siRNA-transfected PANC-1 tumors showed significantly reduced tumor volumes and high gemcitabine sensitivity compared to the control in a mouse xenograft model.

CONCLUSION

High levels of RRN3 expression are associated with poor prognosis and cancer malignancy, such as proliferation, invasion ability, and chemosensitivity in pancreatic cancer. RRN3 targeting with anticancer drugs may be a promising therapeutic strategy to overcome refractory pancreatic cancer.

Effect of metformin on 18F-fluorodeoxyglucose uptake and positron emission tomographic imaging

Metformin is widely used to treat diabetes, but induces changes in glucose uptake in both normal organs and tumors. Here, we review the effects of metformin on the uptake of ¹⁸F-fludeoxyglucose (¹⁸F-FDG) in tissues and tumors, and its influence on ¹⁸F-FDG positron emission tomographic imaging (¹⁸F-FDG PET), as well as the mechanisms involved. This is an important issue, because metformin has diverse effects on tissue uptake of ¹⁸F-FDG, and this can affect the quality and interpretation of PET images. Metformin increases glucose uptake in the gastrointestinal tract, cerebral white matter, and the kidney, while regions of the cerebrum associated with memory show decreased glucose uptake, and the myocardium shows no change. Hepatocellular carcinoma and breast cancer show increased glucose uptake after metformin administration, while thyroid cancer shows decreased uptake, and colon and pancreatic cancers show no change. A high-energy diet increases ¹⁸F-FDG uptake, but this effect is blocked by metformin. Withdrawal of metformin 48 h before PET image acquisition is widely recommended. However, based on our review of the literature, we propose that the differentiation of metformin discontinuation could be reasonable. But future clinical trials are still needed to support our viewpoint.

Hepatic stellate cell as a Mac-2-binding protein-producing cell in patients with liver fibrosis

BACKGROUND

Mac-2 binding protein (M2BP) glycosylated isomer (M2BPGi) is a serum marker of liver fibrosis; M2BPGi is a glycosylated form of M2BP. Hepatocytes and hepatic stellate cells (HSCs) have been studied to determine the source of M2BP. This study proposes to identify the origin of M2BP in fibrotic liver.

METHODS

Using liver fibrosis tissue specimens from 15 patients with liver cancer, M2BP mRNA and M2BP were detected by in situ hybridization and immunohistochemistry, respectively. The expression levels of M2BP mRNA were evaluated with scores of 3, 2, and 1. Fluorescent in situ hybridization was carried out to evaluate the distribution of M2BP mRNA and the activated-HSC marker αSMA mRNA; multicolor fluorescent immunohistochemistry was used for protein localization of M2BP, αSMA, and CD68. The Kruskal-Wallis test analyzed the relationship between M2BP mRNA expression and existing serum fibrosis markers.

RESULTS

M2BP mRNA was expressed in spindle-shaped cells along the fibrous septa and in the perisinusoidal area of the fibrotic liver. The HSC markers αSMA mRNA and M2BP mRNA were colocalized in the spindle-shaped cells; on the protein level, M2BP was expressed in Kupffer cells. M2BP mRNA expression was positively correlated with serum M2BPGi levels. Aspartate transaminase-to-platelet ratio index, Fibrosis-4, hyaluronic acid, and the 15-minute indocyanine green retention rate were significantly correlated with M2BP mRNA expression.

CONCLUSIONS

M2BP mRNA transcription in fibrotic liver was primarily observed in HSCs but not at the M2BP level, which suggests that HSCs might produce and introduce M2BP to Kupffer cells and serum.

Conophylline Inhibits Hepatocellular Carcinoma by Inhibiting Activated Cancer-associated Fibroblasts Through Suppression of G Protein-coupled Receptor 68

Treatment of hepatocellular carcinoma (HCC) is currently challenging. Cancer-associated fibroblasts (CAFs) promote the malignancy of HCC cells via production of cytokines. Conophylline (CnP), a vinca alkaloid obtained from Ervatamia microphylla leaves, has been reported to suppress activation of hepatic stellate cells and liver fibrosis in rats. We examined the efficacy of CnP in suppressing tumor growth in HCC. Specifically, we investigated whether CnP could inhibit CAFs, which were derived from HCC tissues in vitro and in vivo Same as previous reports, CAFs promoted proliferative and invasive ability of HCC cells. CnP suppressed α-smooth muscle actin expression of CAFs, and inhibited their cancer-promoting effects. CnP significantly suppressed CAFs producting cytokines such as IL6, IL8, C-C motif chemokine ligand 2, angiogenin, and osteopontin (OPN). Combined therapy with sorafenib and CnP against HCC cells and CAFs in vivo showed to inhibit tumor growth the most compared with controls and single treatment with CnP or sorafenib. Transcriptome analysis revealed that GPR68 in CAFs was strongly suppressed by CnP. The cancer-promoting effects of cytokines were eliminated by knockdown of GPR68 in CAFs. CnP inhibited the HCC-promoting effects of CAFs by suppressing several HCC-promoting cytokines secreted by CAFs expressing GPR68. Combination therapy with CnP and existing anticancer agents may be a promising strategy for treating refractory HCC associated with activated CAFs.

Preoperative Mac-2 binding protein glycosylation isomer level predicts postoperative ascites in patients with hepatic resection for hepatocellular carcinoma

AIM

Postoperative ascites is one of the most common complications after hepatic resection and is related to liver fibrosis. Mac-2 binding protein glycosylation isomer (M2BPGi) is a reliable and non-invasive marker for assessing liver fibrosis. This study aimed to evaluate whether preoperative M2BPGi level can predict postoperative refractory ascites in patients with curative hepatic resection for hepatocellular carcinoma.

METHODS

The present study retrospectively evaluated 59 patients between January 2016 and June 2018. We assessed the relationship between preoperative M2BPGi levels, expressed as the cut-off index, and postoperative ascites.

RESULTS

The median M2BPGi level was 1.36 (range 0.34-11.56). Postoperative ascites occurred in seven patients (11.9%). Among them, refractory ascites, defined as diuretic-resistant ascites, occurred in four patients (6.8%). Uni- and multivariate analysis showed that preoperative M2BPGi level was the only independent risk factor of postoperative ascites (odds ratio 3.28, P = 0.033). The cut-off values of M2BPGi for postoperative ascites and refractory ascites were 2.41 and 3.10, respectively. Remarkably, there were no patients with postoperative ascites and refractory ascites when the preoperative M2BPGi levels were less than each cut-off value.

CONCLUSION

Our results suggest that M2BPGi level is a reliable and non-invasive surrogate marker for predicting postoperative ascites before curative resection for hepatocellular carcinoma.

Mac-2 binding protein glycan isomer (M2BPGi) is a new serum biomarker for assessing liver fibrosis: more than a biomarker of liver fibrosis

Assessing liver fibrosis is important for predicting the efficacy of antiviral therapy and patient prognosis. Liver biopsy is the gold standard for diagnosing liver fibrosis, despite its invasiveness and problematic diagnostic accuracy. Although noninvasive techniques to assess liver fibrosis are becoming important, reliable serum surrogate markers are not available. A glycoproteomics study aimed at identifying such markers discovered Mac 2-Binding Protein Gylcan Isomer (M2BPGi), which is a reliable marker for assessing liver fibrosis in patients with viral hepatitis and other fibrotic liver diseases such as primary biliary cholangitis, biliary atresia, autoimmune hepatitis, and nonalcoholic fatty liver disease. M2BPGi predicts the development of hepatocellular carcinoma (HCC) in patients infected with hepatitis B and C as well as the prognosis of liver cirrhosis in those with HCC after therapy. The unique features of M2BPGi are as follows: (1) cut-off values differ for the same stages of fibrosis according to the cause of fibrosis; and (2) M2BPGi levels rapidly decrease after patients achieve a sustained antiviral response to hepatitis C virus. These observations cannot be explained if M2BPGi levels reflect the amount of fibrotic tissue. Hepatic stellate cells (HSCs) secrete M2BPGi, which may serve as a messenger between HSCs and Kupffer cells via Mac-2 (galectin 3) that is expressed in Kupffer cells during fibrosis progression. Here we show that M2BPGi is a surrogate marker for assessing HSC activation. These findings may reveal the roles of HSCs in extrahepatic fibrotic disease progression.

High expression of forkhead box protein C2 is associated with aggressive phenotypes and poor prognosis in clinical hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is one of the major causes of tumor death; thus, the identification of markers related to its diagnosis and prognosis is critical. Previous studies have revealed that epithelial-to-mesenchymal transition (EMT) is involved in tumor invasion and metastasis, and the forkhead box protein C2 (FOXC2) has been shown to promote tumor cell proliferation, invasion, and EMT. In the present study, we examined the clinicopathological significance of FOXC2 and EMT-related markers in clinical HCC specimens and identified factors related to the diagnosis and prognosis of HCC.

Methods

The expression of FOXC2 and EMT-related markers was evaluated by immunohistochemistry in 84 cases of hepatocellular carcinoma.

Results

A high expression of FOXC2 was observed in 26 of 84 cases, and expression was significantly correlated with background liver cirrhosis, poor tumor differentiation, high serum AFP, and elevated cell proliferation markers. In addition, this high expression was related to the induction of the Cadherin switch and vimentin expression and was an independent predictor for poor prognosis.

Conclusion

The high expression of FOXC2 in HCC is correlated with tumor malignancy and poor prognosis, suggesting that FOXC2 may be an important prognostic factor for HCC.