Anoikis-resistant cholangiocarcinoma cells display aggressive characteristics and increase STAT3 activation: Anoikis resistance of cholangiocarcinoma cells

Targeting anoikis resistance as a strategy for cancer therapy

Anoikis, known as matrix detachment-induced apoptosis or detachment-induced cell death, is crucial for tissue development and homeostasis. Cancer cells develop means to evade anoikis, e.g. anoikis resistance, thereby allowing for cells to survive under anchorage-independent conditions. Uncovering the mechanisms of anoikis resistance will provide details about cancer metastasis, and potential strategies against cancer cell dissemination and metastasis. Here, we summarize the principal elements and core molecular mechanisms of anoikis and anoikis resistance. We discuss the latest progress of how anoikis and anoikis resistance are regulated in cancers. Furthermore, we summarize emerging data on selective compounds and nanomedicines, explaining how inhibiting anoikis resistance can serve as a meaningful treatment modality against cancers. Finally, we discuss the key limitations of this therapeutic paradigm and possible strategies to overcome them. In this review, we suggest that pharmacological modulation of anoikis and anoikis resistance by bioactive compounds could surmount anoikis resistance, highlighting a promising therapeutic regimen that could be used to overcome anoikis resistance in cancers.

HK2 promotes migration and invasion of intrahepatic cholangiocarcinoma via enhancing cancer stem-like cells' resistance to anoikis

Cancer stem-like cells (CSLCs) and anoikis resistance play crucial roles in the metastasis of cancers. However, it remains unclear whether CSLCs are related to anoikis resistance in intrahepatic cholangiocarcinoma (ICC). Here we identified a group of stemness-related anoikis genes (SRAGs) via bioinformatic analysis of public data. Accordingly, a novel anoikis-related classification was established and it divided ICC into C1 and C2 type. Different type ICC displayed distinct prognosis, molecular as well immune characteristics. Furthermore, we found one key SRAGs via several machine learning algorithms. HK2 was up-regulated in tumor-repopulating cells (TRCs) of ICC, a kind of CSLCs with a potent resistance to anoikis. Its up-regulation may be caused by the activation of MTORC1 signaling in ICC-TRCs. And inhibition of HK2 significantly increased anoikis and decreased migration as well invasion in ICC-TRCs. Our studies provide an insight into the molecular mechanism underlying the resistance of ICC-TRCs to anoikis and enhance the evidences for targeting HK2 in ICC.

Overcoming Acquired Drug Resistance to Cancer Therapies through Targeted STAT3 Inhibition

Anti-neoplastic agents for cancer treatment utilize many different mechanisms of action and, when combined, can result in potent inhibition of cancer growth. Combination therapies can result in long-term, durable remission or even cure; however, too many times, these anti-neoplastic agents lose their efficacy due to the development of acquired drug resistance (ADR). In this review, we evaluate the scientific and medical literature that elucidate STAT3-mediated mechanisms of resistance to cancer therapeutics. Herein, we have found that at least 24 different anti-neoplastic agents-standard toxic chemotherapeutic agents, targeted kinase inhibitors, anti-hormonal agents, and monoclonal antibodies-that utilize the STAT3 signaling pathway as one mechanism of developing therapeutic resistance. Targeting STAT3, in combination with existing anti-neoplastic agents, may prove to be a successful therapeutic strategy to either prevent or even overcome ADR to standard and novel cancer therapies.

Clinical usefulness and acceleratory effect of macrophage inhibitory cytokine-1 on biliary tract cancer: an experimental biomarker analysis

BACKGROUND

Biliary tract cancer (BTC) has a poor prognosis; therefore, useful biomarkers and treatments are needed. Serum levels of macrophage inhibitory cytokine-1 (MIC-1), a member of the TGF-β superfamily, are elevated in patients with pancreaticobiliary cancers. However, the effect of MIC-1 on BTC is unknown. Therefore, we investigated the effect of MIC-1 on BTC and assessed whether MIC-1 is a biomarker of or therapeutic target for BTC.

METHODS

MIC-1 expression in BTC cells was determined by performing histological immunostaining, tissue microarray (TMA), western blotting, and reverse transcription PCR (RT-PCR). Cell culture experiments were performed to investigate the effect of MIC-1 on BTC cell lines (HuCCT-1 and TFK-1). The relationships between serum MIC-1 levels and either the disease state or the serum level of the apoptosis marker M30 were retrospectively verified in 118 patients with pancreaticobiliary disease (individuals with benign disease served as a control group, n = 62; BTC, n = 56). The most efficient diagnostic marker for BTC was also investigated.

RESULTS

MIC-1 expression was confirmed in BTC tissue specimens and was higher in BTC cells than in normal bile duct epithelial cells, as determined using TMA, western blotting and RT-PCR. In cell culture experiments, MIC-1 increased BTC cell proliferation and invasion by preventing apoptosis and inhibited the effect of gemcitabine. In serum analyses, serum MIC-1 levels showed a positive correlation with BTC progression and serum M30 levels. The ability to diagnose BTC at an early stage or at all stages was improved using the combination of MIC-1 and M30. The overall survival was significantly longer in BTC patients with serum MIC-1 < the median than in BTC patients with serum MIC-1 ≥ the median.

CONCLUSIONS

MIC-1 is a useful diagnostic and prognostic biomarker and might be a potential therapeutic target for BTC.

Nintedanib inhibits intrahepatic cholangiocarcinoma aggressiveness via suppression of cytokines extracted from activated cancer-associated fibroblasts

Background

Intrahepatic cholangiocarcinoma (ICC) is a malignancy that is challenging to treat. Fibroblasts in ICC tissues have been identified as cancer-associated fibroblasts (CAFs) that promote the malignant behaviour of ICC cells. An antifibrotic drug nintedanib has been reported to suppress activated hepatic stellate cells in liver fibrosis.

Methods

We investigated whether nintedanib could suppress the cancer-promoting effect of CAFs derived from ICC tissues in vitro and in vivo.

Results

CAFs promoted the proliferation and invasion of ICC cells. Nintedanib suppressed activated CAFs expressing α-smooth muscle actin (α-SMA) and inhibited the ICC-promoting effects of CAFs. Nintedanib greatly reduced the levels of cancer-promoting cytokines, such as interleukin (IL)-6 (IL-6) and IL-8, secreted by CAFs. An in vivo study demonstrated that nintedanib reduced xenografted ICC growth and activated CAFs expressing α-SMA, and that combination therapy with nintedanib and gemcitabine against CAFs and ICC cells showed the strongest inhibition of tumour growth compared with the control and single-treatment groups.

Conclusions

Nintedanib inhibited the cancer-promoting effect of CAFs via the suppression of CAF activation and secretion of cancer-promoting cytokines. Our findings suggest that therapeutic strategies combining conventional cytotoxic agents with nintedanib targeting CAFs are promising for overcoming refractory ICC with activated CAFs.

Curcumin enhances chemotherapeutic effects and suppresses ANGPTL4 in anoikis-resistant cholangiocarcinoma cells

Anoikis resistance is a critical feature involved in tumor progression and chemoresistance. Finding approaches to improve the effect of chemotherapy on anoikis-resistant cancer cells is therefore critically important. In this study, we examined the effects of curcumin in anoikis-resistant cholangiocarcinoma (CCA) cells, including HuCCT1 and TFK-1 that were anchorage-independently cultured (AI-cells) using poly (2-hydroxyethyl methacrylate). The AI-CCA cells were treated with curcumin alone or in combination with anti-cancer agents and their responses to each treatment were determined by cell viability assay. Gene expression in AI-cells was determined by quantitative real-time PCR. The potential involvement of angiopoietin-like 4 (ANGPTL4) in anoikis resistance was examined by gene knockdown. It was found that AI-cells tended to resist anti-cancer agents tested, especially AI-HuCCT1, which significantly resisted gemcitabine and suberoylanilide hydroxamic acid (SAHA). Curcumin alone significantly inhibited viability and colony formation of AI-cells. Moreover, curcumin combination significantly enhanced the treatment effect of SAHA on AI-HuCCT1 and AI-TFK-1 cells. Gene expression analysis revealed that ANGPTL4 was markedly upregulated in AI-CCA cells and its knockdown tended to sensitize AI-cells to cell death and treatments. In addition, curcumin treatment decreased phosphorylated STAT3 and expression levels of Mcl-1, HDACs and ANGPTL4. Altogether, these findings reveal the beneficial property of curcumin to potentiate chemotherapeutic effects on anoikis-resistant CCA cells, which might suggest the potential use of curcumin for cancer treatment.

Signalling networks in cholangiocarcinoma: Molecular pathogenesis, targeted therapies and drug resistance

Cholangiocarcinoma (CCA) is a deadly disease. While surgery may attain cure in a minor fraction of cases, therapeutic options in either the adjuvant or advanced setting are limited. The possibility of advancing the efficacy of therapeutic approaches to CCA relies on understanding its molecular pathogenesis and developing rational therapies aimed at interfering with oncogenic signalling networks that drive and sustain cholangiocarcinogenesis. These efforts are complicated by the intricate biology of CCA, which integrates not only the driving force of tumour cell-intrinsic alterations at the genetic and epigenetic level but also pro-tumorigenic cues conveyed to CCA cells by different cell types present in the rich tumour stroma. Herein, we review our current understanding of the mechanistic bases underpinning the activation of major oncogenic pathways causative of CCA pathogenesis. We subsequently discuss how this knowledge is being exploited to implement rationale-based and genotype-matched therapeutic approaches that predictably will radically transform CCA clinical management in the next decade. We conclude by highlighting the mechanisms of therapeutic resistance in CCA and reviewing innovative approaches to combat resistance at the preclinical and clinical level.

Heparan sulfate proteoglycans as trastuzumab targets in anoikis-resistant endothelial cells

Anoikis is a form of programmed cell death induced by loss of contact from neighboring cells or from their extracellular matrix (ECM). Many tumorigenic cells are anoikis resistant, facilitating cancer progression and metastasis. Trastuzumab is a monoclonal antibody used for the treatment of breast and gastric cell cancer, but its mechanism of action is not well elucidated and its target molecules not well defined. Heparan sulfate proteoglycans (HSPGs) and glycosaminoglycans (GAGs) play important roles in tumor development and in response of cancer cells to drugs. This study investigates the effect of trastuzumab on the expression of HSPGs and sulfated glycosaminoglycans (SGAGs) in anoikis-resistant endothelial cells. After trastuzumab treatment, endothelial cells resistant to anoikis show an increase in adhesion to fibronectin followed by a decrease in invasion, proliferation, and angiogenic capacity. In addition, a significant increase in the number of cells in the S phase of the cell cycle was also observed. In relation to HSPGs and SGAGs expression, we observed a decrease in syndecan-4 and perlecan expression, as well as in the heparan sulfate biosynthesis in anoikis-resistant endothelial cells after exposure to trastuzumab. Our results suggest that trastuzumab interacts with GAGs and proteoglycans of the cell surface and ECM and through this interaction controls cellular events in anoikis-resistant endothelial cells.