Maintenance of stemness in oxaliplatin-resistant hepatocellular carcinoma is associated with increased autocrine of IGF1

The role of IGF/IGF-1R signaling in the regulation of cancer stem cells

Cancer stem cells (CSCs) are a group of tumor cells with high tumorigenic ability and self-renewal potential similar to those of normal stem cells. CSCs are the key "seeds" for tumor development, metastasis, and recurrence. A better insight into the key mechanisms underlying CSC survival improves the efficiency of cancer therapy via specific targeting of CSCs. Insulin-like growth factor (IGF)/IGF-1 receptor (IGF-1R) signaling plays an important role in the maintenance of cancer stemness. However, the effect of IGF/IGF-1R signaling on stemness and CSCs and the underlying mechanisms are still controversial. Based on the similarity between CSCs and normal stem cells, this review discusses emerging data on the functions of IGF/IGF-1R signaling in normal stem cells and CSCs and dissects the underlying mechanisms by which IGF/IGF-1R signaling is involved in CSCs. On the other hand, this review highlighted the role of IGF/IGF-1R signaling blockade in multiple CSCs as a potential strategy to improve CSC-based therapy.

NLRP3/IL-1β induced myeloid-derived suppressor cells recruitment and PD-L1 upregulation promotes oxaliplatin resistance of hepatocellular carcinoma

Oxaliplatin is commonly used as the first-line chemotherapeutic agent for advanced hepatocellular carcinoma (HCC). Unfortunately, the acquired resistance, limits the effectiveness of oxaliplatin and the underlying mechanisms remain unknown. Therefore, we explored the role of NOD-like receptor protein 3 (NLRP3)/IL-1β in mediating oxaliplatin resistance in HCC. We observed that NLRP3/IL-1β expression was much higher in oxaliplatin-resistant HCC cells. To further understand its impact on drug resistance, we knocked down NLRP3 and observed that it sensitized HCC cells to the growth-inhibitory effects of oxaliplatin and induced cell apoptosis. NLRP3/IL-1β overexpressing tumor cells also attracted polymorphonuclear myeloid-derived suppressor cells. Using mouse models, we demonstrated that NLRP3/IL-1β inhibition by short hairpin RNA or MCC950 effectively overcame oxaliplatin resistance. Furthermore, NLRP3/IL-1β inhibition resulted in reduced expression of PD-L1. We also found that PD-L1 antibody combined with NLRP3/IL-1β blockade displayed significant antitumor effect in HCC. Overall, our study provides compelling evidence supporting the essential role of NLRP3/IL-1β in conferring resistance to oxaliplatin and reshaping the immunosuppressive microenvironment in HCC. Targeting NLRP3/IL-1β presents a potential therapeutic target for overcoming oxaliplatin resistance and reshaping microenvironment of HCC.

Oxaliplatin-Resistant Hepatocellular Carcinoma Drives Immune Evasion Through PD-L1 Up-Regulation and PMN-Singular Recruitment

BACKGROUND & AIMS

Previously, we showed the inhibitor of differentiation or DNA binding 1 (ID1)/Myc signaling is highly expressed in oxaliplatin-resistant hepatocellular carcinoma (HCC). This study sought to investigate the role of ID1/Myc signaling on immune evasion in oxaliplatin-resistant HCC.

METHODS

The oxaliplatin (OXA)-resistant HCC cell lines (Hepa 1-6-OXA, 97H-OXA, and 3B-OXA) were established and their oxaliplatin tolerance was confirmed in vitro and in vivo. The relationship between ID1/Myc and programmed death-ligand 1 (PD-L1) up-regulation and polymorphonuclear myeloid-derived suppressor cell (PMN-MDSC) accumulation was explored. The underlying mechanism in which ID1/Myc signaling regulated PD-L1 expression and PMN-MDSC accumulation was investigated in vitro and vivo.

RESULTS

Increased ID1/Myc expression was identified in oxaliplatin-resistant HCC and correlated with PD-L1 up-regulation and PMN-MDSC accumulation. The knockdown of Myc sensitized oxaliplatin-resistant HCC cells to oxaliplatin and resulted in a decrease of PMN-MDSCs and an increase of interferon-γ⁺ CD8⁺ T cells in a tumor microenvironment. Polymerase chain reaction array, enzyme-linked immunosorbent assay, and MDSC Transwell migration assay indicated that oxaliplatin-resistant HCC cells recruited PMN-MDSCs through chemokine (C-C motif) ligand 5 (CCL5). The dual luciferase reporter assay and chromatin immunoprecipitation assay indicated that Myc could directly increase the transcriptions of PD-L1 and CCL5. Furthermore, anti-PD-L1 antibody combined with CCL5 blockade showed significant antitumor effects in oxaliplatin-resistant HCC.

CONCLUSIONS

ID1/Myc signaling drives immune evasion in oxaliplatin-resistant HCC via PD-L1 up-regulation and PMN-MDSC recruitment. Blocking the ID1/Myc-induced immune tolerance represents a promising treatment target to conquer chemoresistance in HCC.

SP1-induced lncRNA DUBR promotes stemness and oxaliplatin resistance of hepatocellular carcinoma via E2F1-CIP2A feedback

Oxaliplatin-based chemotherapy is widely used to treat advanced hepatocellular carcinoma (HCC), but many patients develop drug resistance that leads to tumor recurrence. Cancer stem cells (CSCs) are known to contribute to chemoresistance, the underlying mechanism, however, remains largely unknown. In this study, we discovered a specificity protein 1 (SP1)-induced long noncoding RNA--DPPA2 upstream binding RNA (DUBR) and its high expression in HCC tissues and liver CSCs. DUBR was associated with HCC progression and poor chemotherapy response. Moreover, DUBR facilitated the stemness and oxaliplatin resistance of HCC in vitro and in vivo. Mechanistically, DUBR upregulated cancerous inhibitor of protein phosphatase 2A (CIP2A) expression through E2F1-mediated transcription regulation. DUBR also exerted function by binding microRNA (miR)-520d-5p as a competing endogenous RNA to upregulate CIP2A at mRNA level. CIP2A, in turn, stabilized E2F1 protein and activated the Notch1 signaling pathway, thereby increasing the stemness feature of HCC and leading to chemoresistance. In conclusion, we identified SP1/DUBR/E2F1-CIP2A as a critical axis to activate the Notch1 signaling pathway and promote stemness and chemoresistance of HCC. Therefore, DUBR could be a potential target in HCC treatment.

Inositol hexaphosphate sensitizes hepatocellular carcinoma to oxaliplatin relating inhibition of CCN2-LRP6-β-catenin-ABCG1 signaling pathway

Hepatocellular carcinoma (HCC) is a drastic problem in China. Oxaliplatin, a platinum-based chemotherapy drug, has limited efficacy in treating HCC, characterized by intrinsic and acquired resistance. Inositol hexaphosphate (IP6), a carbohydrate abundant in grains, has contributed to the rising popularity of whole grain products consumption for the potential protection against dozens of diseases. However, the therapeutic potential of IP6 in halting the progression of HCC remains unclear, especially in combination with oxaliplatin. The anti-proliferation and anti-migration effects of IP6 were evaluated in vitro and in vivo. The synergistic and sequential anti-proliferative effect with IP6 and oxaliplatin were also evaluated in HCC. Finally, the role of CCN2-LRP6-β-catenin-ABCG1 signaling in oxaliplatin resistance and IP6 treatment was evaluated. We proved that IP6 treatment exhibited independent anticancer effect and synergistic anti-proliferative effects in combination with oxaliplatin in HCC. Specifically, up-regulation of ABCG1 and CCN2 were associated with oxaliplatin resistance. ABCG1 was acting as a downstream molecule of the CCN2-LRP6-Wnt/β-catenin signaling pathway in HCC cells. The IP6 treatment exhibited inhibition of CCN2-LRP6-Wnt/β-catenin signaling pathway and downregulation of ABCG1 in HCC cells. When combined with ABCG1 knocking down in HCC cells, the anti-proliferative effect of oxaliplatin was partly impaired in combination with IP6. We suggested that IP6 treatment renders HCC sensitive to oxaliplatin and breaking the CCN2-LRP6-β-catenin-ABCG1 signaling pathway is one of the mechanism after IP6 treatment.

OSCAR facilitates malignancy with enhanced metastasis correlating to inhibitory immune microenvironment in multiple cancer types

Cross talk between tumors and the immune microenvironment play a critical role in the malignant progression. The osteoclast-associated receptor (OSCAR) is a regulator of lymphocyte differentiation and maturation, but little is known about the role of OSCAR in multiple cancer types. We comprehensively analyzed OSCAR expression and explored its correlation with prognosis in multiple cancer types using Oncomine, TIMER, Gene GEPIA2 and CCLE. We examined OSCAR expression correlations with lymph node metastasis and pathological stage across tumor samples using UALCAN and GEPIA2. We analyzed the effects of OSCAR on survival using the Kaplan Meier plotter. We explored genes co-expressed with OSCAR using the LinkedOmics database and analyzed associated gene ontologies using Metascape. Further, we examined the correlation between OSCAR expression and immunocyte infiltration, markers of epithelial-mesenchymal transition, and lymphocyte subtypes using TIMER. OSCAR mRNA levels were upregulated in most cancer types compared with adjacent normal tissues. Higher expression of OSCAR correlated with lymph node metastasis or advanced stage subgroups. High expression of OSCAR was related to low tumor purity, with increased levels of M2 macrophage polarization, T cells exhaustion, and mesenchymal phenotype in most cancer types. We also showed that the strength of OSCAR expression influence in malignant progression and inhibitory immune microenvironment is mitigated by the infiltration of natural killer cells. These findings shed light on the pro-carcinogenic role of OSCAR in most cancer types and indicate OSCAR could be targeted in future therapeutics to reverse the inhibitory immune microenvironment.

The Role of IGF/IGF-1R Signaling in Hepatocellular Carcinomas: Stemness-Related Properties and Drug Resistance

Insulin-like Growth Factor (IGF)/IGF-1 Receptor (IGF-1R) signaling is known to regulate stem cell pluripotency and differentiation to trigger cell proliferation, organ development, and tissue regeneration during embryonic development. Unbalanced IGF/IGF-1R signaling can promote cancer cell proliferation and activate cancer reprogramming in tumor tissues, especially in the liver. Hepatocellular carcinoma (HCC) is one of the leading causes of cancer-related death, with a high incidence and mortality rate in Asia. Most patients with advanced HCC develop tyrosine kinase inhibitor (TKI)-refractoriness after receiving TKI treatment. Dysregulation of IGF/IGF-1R signaling in HCC may activate expression of cancer stemness that leads to TKI refractoriness and tumor recurrence. In this review, we summarize the evidence for dysregulated IGF/IGF-1R signaling especially in hepatitis B virus (HBV)-associated HCC. The regulation of cancer stemness expression and drug resistance will be highlighted. Current clinical treatments and potential therapies targeting IGF/IGF-1R signaling for the treatment of HCC will be discussed.

Integrated Bioinformatics Analysis Reveals Key Candidate Genes and Pathways Associated With Clinical Outcome in Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) accounts for approximately 85-90% of all liver cancer cases and has poor relapse-free survival. There are many gene expression studies that have been performed to elucidate the genetic landscape and driver pathways leading to HCC. However, existing studies have been limited by the sample size and thus the pathogenesis of HCC is still unclear. In this study, we performed an integrated characterization using four independent datasets including 320 HCC samples and 270 normal liver tissues to identify the candidate genes and pathways in the progression of HCC. A total of 89 consistent differentially expression genes (DEGs) were identified. Gene-set enrichment analysis revealed that these genes were significantly enriched for cellular response to zinc ion in biological process group, collagen trimer in the cellular component group, extracellular matrix (ECM) structural constituent conferring tensile strength in the molecular function group, protein digestion and absorption, mineral absorption and ECM-receptor interaction. Network system biology based on the protein-protein interaction (PPI) network was also performed to identify the most connected and important genes based on our DEGs. The top five hub genes including osteopontin (SPP1), Collagen alpha-2(I) chain (COL1A2), Insulin-like growth factor I (IGF1), lipoprotein A (LPA), and Galectin-3 (LGALS3) were identified. Western blot and immunohistochemistry analysis were employed to verify the differential protein expression of hub genes in HCC patients. More importantly, we identified that these five hub genes were significantly associated with poor disease-free survival and overall survival. In summary, we have identified a potential clinical significance of these genes as prognostic biomarkers for HCC patients who would benefit from experimental approaches to obtain optimal outcome.

Oxaliplatin resistance is enhanced by saracatinib via upregulation Wnt-ABCG1 signaling in hepatocellular carcinoma

BACKGROUND

Chemo-resistance in hepatocellular carcinoma (HCC) is a major problem, and acquired drug resistance prevents cancer therapies from achieving complete responses. Molecular targeting therapy presents an opportunity to impede tumor through combination or sequential therapy, while the accurate effect is vague.

METHODS

The efficacy of combinations between oxaliplatin and anti-cancer molecular targeting drugs was screened. Strangely, the combined chemotherapy with oxaliplatin and saracatinib induced significantly antagonistic effects. Then the antitumor effects of combined treatment with saracatinib and oxaliplatin were confirmed in wide type HCC as well as in saracatinib- and oxaliplatin-resistant HCC. RNA sequencing was used to explore the resistance mechanism, and the roles of ATP-binding cassette transporter G1 (ABCG1) and Wnt signaling in oxaliplatin resistance were confirmed.

RESULTS

Chemotherapy with oxaliplatin and saracatinib individually induced strong anti-HCC effects, while combined or sequential treatment of HCC cells with these two drugs exhibited reduced efficacy compared to treatment with the single drugs. And it was saracatinib treatment caused oxaliplatin resistance. RNA sequencing revealed 458 genes that were altered by treatment with saracatinib and oxaliplatin. Of these, the gene encoding ABCG1 and Wnt-associated genes were significantly upregulated. Upregulation of ABCG1 and oxaliplatin resistance were associated with activation of Wnt signaling. Interference with ABCG1 expression or inhibition of Wnt signaling resulted in reversal of the saracatinib-induced oxaliplatin resistance in HCC.

CONCLUSIONS

These studies demonstrated that combined or sequential chemotherapy with oxaliplatin and saracatinib reduced antitumor efficacy, and this antagonism was attributed to the activation of Wnt signaling and upregulation of ABCG1 by saracatinib.

Remodeling of hepatic stellate cells orchestrated the stroma-derived oxaliplatin-resistance through CCN3 paracrine in hepatocellular carcinoma

BACKGROUND

Hepatic stellate cells (HSCs) have a key role in fibrogenesis and in the filtrates of the hepatocellular carcinoma (HCC) stroma, in which they are remodeled and play a critical role in HCC progression. However, the precise role of HSCs trending, infiltration and paracrine in orchestrating the stroma-derived oxaliplatin-resistance in HCC is still vague.

METHODS

The chemo-resistant models were established to explore the correlation between HSC cells and the condition of chemoresistance. The HCC clinical samples were collected to confirm this phenomenon. Then, the relationship between secretory CCN3 from oxaliplatin-resistant HCC and the infiltration of HSCs in associated HCC microenvironment was evaluated. Finally, the role and mechanism of HSCs remodeling in the orchestration of oxaliplatin-resistant HCC were explored.

RESULTS

The increased infiltration of HSCs and collagen accumulation were found in the microenvironment of oxaliplatin-resistant HCC. The cDNA profiles of the oxaliplatin-resistant HCC was reanalyzed, and CCN3 was one of the significantly increased genes. In HCC clinical samples, the levels of CCN3 and α-SMA are positively correlated, and high expression of CCN3 and α-SMA are positively associated with malignant phenotype and poor prognosis. Then the enhanced abilities of migration and proliferation of HSCs, and elevation of the cytokines paracrine from HSCs relating to HCC malignancy were proved in vitro and in vivo, and which were related to CCN3-ERK signaling pathway activation.

CONCLUSIONS

HSCs remodeling are positively related to CCN3 paracrine in hepatocellular carcinoma, which orchestrated the stroma-derived resistance to chemotherapy in HCC.

HSF1/AMPKα2 mediated alteration of metabolic phenotypes confers increased oxaliplatin resistance in HCC cells

Recent studies suggest that up-regulated HSF1 possesses metabolic phenotypes switch and chemoresistance in cancer cells. However, the mechanism in which these characteristics are still ambiguous. Our study aims to identify how HSF1 confers chemoresistance through regulating metabolic pathway in hepatocellular carcinoma (HCC). Oxaliplatin (OXA)-resistant HCC cells (HCC-OXR) in both of abundant glucose (AG; 25 mM) and low glucose (LG; 5.5 mM) conditions were constructed; then glucose consumption, lactate production, intracellular ATP level and oxygen consumption of parental and OXA-resistant cells were determined by using the associated detected kits. Moreover, HSF1 was knocked down to analyze its effects on metabolic phenotypes alteration and chemoresistance formation in HCC cells. Compared to cells in AG condition, HCC cells delayed to form chemoresistance to OXA in LG condition; and OXA-resistant cells underwent a metabolic switch from glycolysis to oxidative phosphorylation (OXPHOS), which presented decreased glucose uptake and lactate production with increased levels of oxygen consumption and intercellular ATP; interestingly, this energy-producing pathway was blocked in HSF1-knockdown OXA-resistant cells, especially in LG condition. Analysis on previous data revealed that AMPK pathway was a critical regulator in the metabolism of OXA-resistance HCC cells. Furthermore, AMPKα2 was identified as an important factor regulated by HSF1 to achieve metabolic phenotype switch in OXA-resistance HCC cells. Consequently, these results suggest that combining restrictive glucose uptake and targeting HSF1/AMPKα2 is an attractive strategy to prevent chemoresistance to OXA in HCC patients.

CCN2-MAPK-Id-1 loop feedback amplification is involved in maintaining stemness in oxaliplatin-resistant hepatocellular carcinoma

Background

Hepatocellular carcinoma (HCC) is the second leading cause of cancer death worldwide. Chemotherapy is an alternative treatment for advanced HCCs, but chemo-resistance prevents cancer therapies from achieving stable and complete responses. Understanding the underlying mechanisms in chemo-resistance is critical to improve the efficacy of HCC.

Methods

The expression levels of Id-1 and CCN2 were detected in large cohorts of HCCs, and functional analyses of Id-1 and CCN2 were performed both in vitro and in vivo. cDNA microarrays were performed to evaluate the alterations of expression profiling of HCC cells with overexpression of CCN2. Finally, the role of downstream signaling of MAPK/Id-1 signaling pathway in oxaliplatin resistance were also explored.

Results

The increased expression of Id-1 and CCN2 were closely related to oxaliplatin resistance in HCC. Upregulation of CCN2 and Id-1 was independently associated with shorter survival and increased recurrence in HCC patients, and significantly enhanced oxaliplatin resistance and promoted lung metastasis in vivo, whereas knock-down of their expression significantly reversed the chemo-resistance and inhibited HCC cell stemness. cDNA microarrays and PCR revealed that Id-1 and MAPK pathway were the downstream signaling of CCN2. CCN2 significantly enhanced oxaliplatin resistance by activating the MAPK/Id-1 signaling pathway, and Id-1 could upregulate CCN2 in a positive feedback manner.

Conclusions

CCN2/MAPK/Id-1 loop feedback amplification is involved in oxaliplatin resistance, and the combination of oxaliplatin with inhibitor of CCN2 or MAPK signaling could provide a promising approach to ameliorating oxaliplatin resistance in HCC.

Electronic supplementary material

The online version of this article (10.1007/s12072-019-09960-5) contains supplementary material, which is available to authorized users.

Paracrine effects of CCN3 from non-cancerous hepatic cells increase signaling and progression of hepatocellular carcinoma

BACKGROUND

The liver microenvironment plays a key role in the progression and metastasis of hepatocellular carcinoma (HCC). Gene expression profiling of non-cancerous hepatic tissues obtained from patients with metastatic HCC exhibit a unique immune response signature, including upregulation of CCN3. However, the role of CCN3 secreted from non-cancerous hepatic tissues in the progression of HCC remains unclear.

METHODS

Using tissue microarrays, we examined CCN3 in non-cancerous hepatic tissues of patients with HCC and correlated expression with clinical and pathological features. In addition, CCN3 localization and mechanisms of HCC progression were investigated in tissues and cell lines. Finally, correlations between CCN3 and cirrhosis were explored in patients.

RESULTS

CCN3 was primarily localized to hepatic cells of non-cancerous hepatic tissues and was associated with vascular invasion and poor prognosis in patients with HCC. CCN3 expression in non-cancerous hepatic tissues also correlated with the degree of liver fibrosis. Compared with conditioned media from wild-type LO2 cells, conditioned media from hepatic cell line LO2 activated by LX2 (aLO2-CM) induced CCN3 expression and HCC cell proliferation and metastasis. Further, aLO2-CM activated MAPK signaling and epithelial-mesenchymal transition in HCC cells. Finally, CCN3 was inversely related to cirrhosis in the prognosis of HCC and negatively regulated hepatic stellate cells (HSCs) in vitro with downregulation of α-SMA, TGF-β, and collagens.

CONCLUSIONS

CCN3 was secreted from hepatic cells activated by HSCs and increased MAPK signaling, EMT, proliferation and metastasis of HCC cells. CCN3 was also inversely related to cirrhosis, regulating HSCs through a negative feedback loop.

Cancer Stem Cells: Emergent Nature of Tumor Emergency

A functional analysis of 167 genes overexpressed in Krebs-2 tumor initiating cells was performed. In the first part of the study, the genes were analyzed for their belonging to one or more of the three groups, which represent the three major phenotypic manifestation of malignancy of cancer cells, namely (1) proliferative self-sufficiency, (2) invasive growth and metastasis, and (3) multiple drug resistance. 96 genes out of 167 were identified as possible contributors to at least one of these fundamental properties. It was also found that substantial part of these genes are also known as genes responsible for formation and/or maintenance of the stemness of normal pluri-/multipotent stem cells. These results suggest that the malignancy is simply the ability to maintain the stem cell specific genes expression profile, and, as a consequence, the stemness itself regardless of the controlling effect of stem niches. In the second part of the study, three stress factors combined into the single concept of "generalized cellular stress," which are assumed to activate the expression of these genes, were defined. In addition, possible mechanisms for such activation were identified. The data obtained suggest the existence of a mechanism for the de novo formation of a pluripotent/stem phenotype in the subpopulation of "committed" tumor cells.

Huaier Augmented the Chemotherapeutic Sensitivity of Oxaliplatin via Downregulation of YAP in Hepatocellular Carcinoma

For unresectable Hepatocellular carcinoma (HCC), chemotherapy is still an important treatment strategy. Oxaliplatin (Oxa) is an effective treatment of HCC after sorafenib treatment failure. However, the intrinsic or acquired resistance of Oxa affected the chemotherapeutic sensitivity. By analyzing the data of GEO Database, we found that Oxa aberrantly increased the expression of Cysteine-rich61 (Cyr61) in HCC cell lines. Subsequently, in Bel-7404 and SMMC-7721 cells after treated with Oxa, it was verified that the expression of Cyr61 and Yes-associated protein (YAP) was increased. Moreover, we found that blockade of YAP promoted Oxa-induced cell apoptosis for the first time. Meanwhile, our previous study demonstrated that Huaier (HE) inhibited the expression of YAP. Further study found that combination treatment of Oxa and HE had a significantly synergistic anti-cancer effect and significantly inhibited the expression of YAP and apoptosis related proteins. Taken together, we have observed that overexpression of YAP significantly reduced the chemotherapeutic sensitivity of Oxa in HCC for the first time. Combination treatment of Oxa and HE solved this problem.

ID1 promotes hepatocellular carcinoma proliferation and confers chemoresistance to oxaliplatin by activating pentose phosphate pathway

Background

Drug resistance is one of the major concerns in the treatment of hepatocellular carcinoma (HCC). The aim of the present study was to determine whether aberrant high expression of the inhibitor of differentiation 1(ID1) confers oxaliplatin-resistance to HCC by activating the pentose phosphate pathway (PPP).

Methods

Aberrant high expression of ID1 was detected in two oxaliplatin-resistant cell lines MHCC97H–OXA(97H–OXA) and Hep3B–OXA(3B–OXA). The lentiviral shRNA or control shRNA was introduced into the two oxaliplatin-resistant cell lines. The effects of ID1 on cell proliferation, apoptosis and chemoresistance were evaluated in vitro and vivo. The molecular signaling mechanism underlying the induction of HCC proliferation and oxaliplatin resistance by ID1 was explored. The prognostic value of ID1/G6PD signaling in HCC patients was assessed using the Cancer Genome Atlas (TCGA) database.

Results

ID1 was upregulated in oxaliplaitin-resistant HCC cells and promoted HCC cell proliferation and oxaliplatin resistance. Silencing ID1 expression in oxaliplaitin-resistant HCC cell lines inhibited cell proliferation and sensitized oxaliplaitin-resistant cells to death. ID1 knockdown significantly decreased the expression of glucose-6-phosphate dehydrogenase (G6PD), a key enzyme of the PPP. Silencing ID1 expression blocked the activation of G6PD, decreased the production of PPP NADPH, and augmented reactive oxygen and species (ROS), thus inducing cell apoptosis. Study of the molecular mechanism showed that ID1 induced G6PD promoter transcription and activated PPP through Wnt/β-catenin/c-MYC signaling. In addition, ID1/G6PD signaling predicted unfavorable prognosis of HCC patients on the basis of TCGA.

Conclusions

Our study provided the first evidence that ID1 conferred oxaliplatin resistance in HCC by activating the PPP. This newly defined pathway may have important implications in the research and development of new more effective anti-cancer drugs.

Electronic supplementary material

The online version of this article (10.1186/s13046-017-0637-7) contains supplementary material, which is available to authorized users.

FGF1 and IGF1-conditioned 3D culture system promoted the amplification and cancer stemness of lung cancer cells

Lung cancer stem cells (LCSCs) are considered as the cellular origins of metastasis and relapse of lung cancer. However, routine two-dimensional culture system (2D-culture) hardly mimics the growth and functions of LCSCs in vivo and therefore significantly decreases the stemness activity of LCSCs. In this study, we constructed a special BME-based three-dimensional culture system (3D-culture) to amplify LCSCs in human lung adenocarcinoma cell line A549 cells and found 3D-culture promoted the enrichment and amplification of LCSCs in A549 cells displaying higher proliferation potential and invasion activity, but lower apoptosis. The expression and secretion levels of FGF1 and IGF1 were dramatically elevated in 3D-culture compared to 2D-culture. After growing in FGF1 and IGF1-conditioned 3D-culture, the proportion of LCSCs with specific stemness phenotypes in A549 cells significantly increased compared to that in conventional 3D suspension culture system. Further results indicated that FGF1 and IGF1 promoted the amplification and cancer stemness of LCSCs dependent on MAPK signaling pathway. Our data firstly established a growth factors-conditioned 3D-culture for LCSCs and demonstrated the effects of FGF1 and IGF1 in promoting the enrichment and amplification of LCSCs which might provide a feasible cell model in vitro for both mechanism study and translational research on lung cancer.

Maintenance of stemness is associated with the interation of LRP6 and heparin-binding protein CCN2 autocrined by hepatocellular carcinoma

Background

The overall response rate of hepatocellular carcinoma (HCC) to chemotherapy is poor. In our previous study, oxaliplatin-resistant HCC is found to exhibit an enhanced stemness, and increased levels of CCN2 and LRP6, while the role of CCN2 and LRP6 in the prognosis of HCC patients, and the interaction regulation mechanism between CCN2 and LRP6 are still unclear.

Methods

The expression levels of CCN2 and LRP6 were detected in large cohorts of HCCs, and functional analyses of CCN2 and LRP6 were performed both in vitro and in vivo. The roles of cell surface heparin sulfate proteoglycans (HSPGs) in the mutual regulatory between CCN2 and LRP6 were verified in HCC, and the interventions of low molecular weight heparin sodium (LMWH) were explored.

Results

CCN2 and LRP6 were overexpressed in HCCs, and the CCN2 and LRP6 levels were positively associated with the malignant phenotypes and poor prognosis of HCCs. LRP6 could significantly upregulate the expression of CCN2. Meanwhile, CCN2 was able to enhance malignant phenotype of HCC cells in a dose-dependent manner through binding with LRP6; and knock-down of LRP6 expression, perturbation of HSPGs, co-incubation of CCN2 with LMWH could significantly block the adhesion of CCN2 to LRP6. LMWH enhanced the therapeutic effect of oxaliplatin on HCC with a high CCN2 expression.

Conclusions

 CCN2 plays a promoting role in HCC progression through activating LRP6 in a HSPGs-dependent manner. Heparin in combination with chemotherapy has a synergic effect and could be a treatment choice for HCCs with a high CCN2 expression. 

Electronic supplementary material

The online version of this article (doi:10.1186/s13046-017-0576-3) contains supplementary material, which is available to authorized users.

Bufalin reverses acquired drug resistance by inhibiting stemness in colorectal cancer cells

Drug resistance is an obstacle to chemotherapy in tumor patients. Recent studies have shown that the high stemness of cancer cells may be induced by chemotherapeutic drugs, which is correlated with drug resistance. In the present study, we investigated the effects of bufalin on the stemness of colorectal cancer. We found that cisplatin could induce high stemness through the tumorsphere formation assay in vitro and in vivo in the colorectal cancer cell lines HCT116 and LoVo. In addition, cisplatin-treated tumorsphere cells showed drug-resistant properties. These results suggested that acquired drug resistance induced by cisplatin in colorectal cancer cells occurred via high stemness. On assessing the effects of bufalin, a traditional Chinese medicine monomer, we found that it could reverse the high stemness and drug resistance induced by cisplatin in colorectal cancer. These findings suggest that bufalin plays an adjuvant role in colorectal cancer chemotherapy and may help reverse acquired drug resistance. These findings may aid in the development of new therapeutic strategies.

IGF-1 contributes to the expansion of melanoma-initiating cells through an epithelial-mesenchymal transition process

Melanoma is a particularly virulent human cancer, due to its resistance to conventional treatments and high frequency of metastasis. Melanomas contain a fraction of cells, the melanoma-initiating cells (MICs), responsible for tumor propagation and relapse. Identification of the molecular pathways supporting MICs is, therefore, vital for the development of targeted treatments. One factor produced by melanoma cells and their microenvironment, insulin-like growth factor-1 (IGF- 1), is linked to epithelial-mesenchymal transition (EMT) and stemness features in several cancers.We evaluated the effect of IGF-1 on the phenotype and chemoresistance of B16-F10 cells. IGF-1 inhibition in these cells prevented malignant cell proliferation, migration and invasion, and lung colony formation in immunodeficient mice. IGF-1 downregulation also markedly inhibited EMT, with low levels of ZEB1 and mesenchymal markers (N-cadherin, CD44, CD29, CD105) associated with high levels of E-cadherin and MITF, the major regulator of melanocyte differentiation. IGF-1 inhibition greatly reduced stemness features, including the expression of key stem markers (SOX2, Oct-3/4, CD24 and CD133), and the functional characteristics of MICs (melanosphere formation, aldehyde dehydrogenase activity, side population). These features were associated with a high degree of sensitivity to mitoxantrone treatment.In this study, we deciphered new connections between IGF-1 and stemness features and identified IGF-1 as instrumental for maintaining the MIC phenotype. The IGF1/IGF1-R nexus could be targeted for the development of more efficient anti-melanoma treatments. Blocking the IGF-1 pathway would improve the immune response, decrease the metastatic potential of tumor cells and sensitize melanoma cells to conventional treatments.

Identification of long noncoding RNA expression profile in oxaliplatin-resistant hepatocellular carcinoma cells

Hepatocellular carcinoma (HCC) is the most prevalent and malignant type of liver cancer. Besides the high incidence, the resistance to chemotherapy is a major problem that leads to the high mortality of HCC. Recently, aberrant expression of long noncoding RNAs (lncRNAs) has been considered as a primary feature of many types of cancer. However, the genome-wide expression pattern and associated functional implications of lncRNAs in chemo-resistant HCC cells remain unknown. In this study, we identified 120 differentially expressed lncRNAs with 61 up-regulated and 59 down-regulated (fold change>2, p<0.05) along with 421 differentially expressed mRNAs with 228 up-regulated and 193 down-regulated (fold change>2, p<0.05) in oxaliplatin-resistant (MHCC97H-OXA) HCC cells, compared to parental oxaliplatin-sensitive (MHCC97H) by microarray. The underlying pathways were related to cell death, proliferation, cellular response to stimulus, including p53 pathway, ErbB pathway and MAPK pathway. Further, 16 lncRNAs were selected for validation of microarray results with quantitative PCR, and a strong correlation was identified between the qPCR results and microarray data. We demonstrated for the first time that ENST00000438347, NR_073453 and ENST00000502804 were up-regulated in MHCC97H-OXA cells as well as chemo-resistant HCC cancerous tissues. Moreover, the expression of ENST00000518376 was significantly associated with the tumor size and differentiation. Overall survival analysis showed that high expression of ENST00000438347 and ENST00000518376 was associated with poor prognosis in HCC patients. Taken together, our results reveal that the expression profile in oxaliplatin-resistant HCC is significantly altered including lncRNAs. And a series of de novo lncRNAs play important functions in HCC oxaliplatin resistance and HCC progression.

CCN: core regulatory proteins in the microenvironment that affect the metastasis of hepatocellular carcinoma?

Hepatocellular carcinoma (HCC) results from an underlying chronic liver inflammatory disease, such as chronic hepatitis B or C virus infections, and the general prognosis of patients with HCC still remains extremely dismal because of the high frequency of HCC metastases. Throughout the process of tumor metastasis, tumor cells constantly communicate with the surrounding microenvironment and improve their malignant phenotype. Therefore, there is a strong rationale for targeting the tumor microenvironment as primary treatment of HCC therapies. Recently, CCN family proteins have emerged as localized multitasking signal integrators in the inflammatory microenvironment. In this review, we summarize the current knowledge of CCN family proteins in inflammation and the tumor. We also propose that the CCN family proteins may play a central role in signaling the tumor microenvironment and regulating the metastasis of HCC.

Understanding why aspirin prevents cancer and why consuming very hot beverages and foods increases esophageal cancer risk. Controlling the division rates of stem cells is an important strategy to prevent cancer

Cancer is, in essence, a stem cell disease. The main biological cause of cancer is that stem cells acquire DNA alterations during cell division. The more stem cell divisions a tissue accumulates over a lifetime, the higher is the risk of cancer in that tissue. This explains why cancer is diagnosed millions of times more often in some tissues than in others, and why cancer incidence increases so dramatically with age. It may also explain why taking a daily low-dose aspirin for several years reduces the risk of developing and dying from cancer. Since aspirin use reduces PGE2 levels and PGE2 fuels stem cell proliferation, aspirin may prevent cancer by restricting the division rates of stem cells. The stem cell division model of cancer may also explain why regular consumption of very hot foods and beverages increases the risk of developing esophageal cancer. Given that tissue injury activates stem cell division for repair, the thermal injury associated with this dietary habit will increase esophageal cancer risk by inducing the accumulation of stem cell divisions in the esophagus. Using these two examples, here I propose that controlling the division rates of stem cells is an essential approach to preventing cancer.

Insulin-like growth factor (IGF) signaling in tumorigenesis and the development of cancer drug resistance

One of the greatest obstacles to current cancer treatment efforts is the development of drug resistance by tumors. Despite recent advances in diagnostic practices and surgical interventions, many neoplasms demonstrate poor response to adjuvant or neoadjuvant radiation and chemotherapy. As a result, the prognosis for many patients afflicted with these aggressive cancers remains bleak. The insulin-like growth factor (IGF) signaling axis has been shown to play critical role in the development and progression of various tumors. Many basic science and translational studies have shown that IGF pathway modulators can have promising effects when used to treat various malignancies. There also exists a substantial body of recent evidence implicating IGF signaling dysregulation in the dwindling response of tumors to current standard-of-care therapy. By better understanding both the IGF-dependent and -independent mechanisms by which pathway members can influence drug sensitivity, we can eventually aim to use modulators of IGF signaling to augment the effects of current therapy. This review summarizes and synthesizes numerous recent investigations looking at the role of the IGF pathway in drug resistance. We offer a brief overview of IGF signaling and its general role in neoplasia, and then delve into detail about the many types of human cancer that have been shown to have IGF pathway involvement in resistance and/or sensitization to therapy. Ultimately, our hope is that such a compilation of evidence will compel investigators to carry out much needed studies looking at combination treatment with IGF signaling modulators to overcome current therapy resistance.