Inhibition of tumor cell growth in the liver by RNA interference-mediated suppression of HIF-1alpha expression in tumor cells and hepatocytes

Emerging nanobiotechnology for precise theranostics of hepatocellular carcinoma

Primary liver cancer has become the second most fatal cancer in the world, and its five-year survival rate is only 10%. Most patients are in the middle and advanced stages at the time of diagnosis, losing the opportunity for radical treatment. Liver cancer is not sensitive to chemotherapy or radiotherapy. At present, conventional molecularly targeted drugs for liver cancer show some problems, such as short residence time, poor drug enrichment, and drug resistance. Therefore, developing new diagnosis and treatment methods to effectively improve the diagnosis, treatment, and long-term prognosis of liver cancer is urgent. As an emerging discipline, nanobiotechnology, based on safe, stable, and efficient nanomaterials, constructs highly targeted nanocarriers according to the unique characteristics of tumors and further derives a variety of efficient diagnosis and treatment methods based on this transport system, providing a new method for the accurate diagnosis and treatment of liver cancer. This paper aims to summarize the latest progress in this field according to existing research and the latest clinical diagnosis and treatment guidelines in hepatocellular carcinoma (HCC), as well as clarify the role, application limitations, and prospects of research on nanomaterials and the development and application of nanotechnology in the diagnosis and treatment of HCC.

Worenine reverses the Warburg effect and inhibits colon cancer cell growth by negatively regulating HIF-1α

Background

Some natural compounds inhibit cancer cell growth in various cancer cell lines with fewer side effects than traditional chemotherapy. Here, we explore the pharmacological effects and mechanisms of worenine (isolated from Coptis chinensis) against colorectal cancer.

Methods

The effects of worenine on colorectal cancer cell proliferation, colony formation and cell cycle distribution were measured. Glycolysis was investigated by examining glucose uptake and consumption, lactate production, and the activities and expressions of glycolysis enzymes (PFK-L, HK2 and PKM2). HIF-1α was knocked down and stimulated in vitro to investigate the underlying mechanisms.

Results

Worenine somewhat altered the glucose metabolism and glycolysis (Warburg effect) of cancer cells. Its anti-cancer effects and capability to reverse the Warburg effect were similar to those of HIF-1α siRNA and weakened by deferoxamine (an HIF-1α agonist).

Conclusion

It is suggested that worenine targets HIF-1α to inhibit colorectal cancer cell growth, proliferation, cell cycle progression and the Warburg effect.

Supplementary Information

The online version contains supplementary material available at 10.1186/s11658-021-00263-y.

Modulating the Crosstalk between the Tumor and Its Microenvironment Using RNA Interference: A Treatment Strategy for Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) is the most common primary liver malignancy with one of the highest mortality rates among solid cancers. It develops almost exclusively in the background of chronic liver inflammation, which can be caused by viral hepatitis, chronic alcohol consumption or an unhealthy diet. Chronic inflammation deregulates the innate and adaptive immune responses that contribute to the proliferation, survival and migration of tumor cells. The continuous communication between the tumor and its microenvironment components serves as the overriding force of the tumor against the body's defenses. The importance of this crosstalk between the tumor microenvironment and immune cells in the process of hepatocarcinogenesis has been shown, and therapeutic strategies modulating this communication have improved the outcomes of patients with liver cancer. To target this communication, an RNA interference (RNAi)-based approach can be used, an innovative and promising strategy that can disrupt the crosstalk at the transcriptomic level. Moreover, RNAi offers the advantage of specificity in comparison to the treatments currently used for HCC in clinics. In this review, we will provide the recent data pertaining to the modulation of a tumor and its microenvironment by using RNAi and its potential for therapeutic intervention in HCC.

Small interfering RNA-mediated gene suppression as a therapeutic intervention in hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the lethal and difficult-to-cure cancers worldwide. Owing to the late diagnosis and drug resistance of malignant hepatocytes, treatment of this cancer by conventional chemotherapy agents is challenging, and researchers are seeking new alternative treatment options to overcome therapy resistance in this neoplasm. RNA interference (RNAi) is a potent and specific approach in targeting gene expression and has emerged as a novel therapeutic tool for many diseases, including cancers. Small interfering RNA (siRNA) is a type of RNAi that is produced intracellularly from exogenous synthetic oligonucleotides and can selectively knock down target gene expression in a sequence-specific manner. Various factors play roles in the initiation and progression of HCC and provide multiple candidate targets for siRNA intervention. In addition, due to the liver's unique architecture and availability of some hepatic siRNA delivery methods, this organ has received much more attention as a target tissue for such oligonucleotide action. Recent advances in designing nanoparticle systems for the in vivo delivery of siRNAs have markedly enhanced the potency of siRNA-mediated gene silencing under clinical development for HCC therapy. The utility of siRNAs as anti-HCC agents is the subject of the current review. siRNA-based gene therapies could be one of the main feasible approaches for HCC therapy in the future.

Silencing HIF-1α aggravates growth inhibition and necrosis of proximal renal tubular epithelial cell under hypoxia

The kidney is particularly susceptible to ischemia/hypoxia insult while dysfunction of proximal tubular epithelial cells (PTEC) is a primary pathologic hallmark in acute kidney injury. Hypoxia-inducible factor-1 (HIF-1) is a key regulator responsible for cellular hypoxic responses. Therefore, we investigated the effects of HIF-1 suppression, using small interference RNA (siRNA), upon the cell fate of PTEC under hypoxia, and explored the underlying possible molecular mechanism. Hypoxia was induced with hypoxia mimetic cobalt chloride. Our data showed that, in HIF-1α siRNA group, the HK-2 cells growth inhibition and necrosis became worse than those in hypoxia group. However, for apoptosis, no significant difference was observed between them. Consistent with the downregulation of HIF-1α in HIF-1α siRNA group, both mRNA and protein expression of glucose transporter-1 (Glut-1) and vascular endothelial growth factor (VEGF) also reduced more significantly than those in hypoxia group. In conclusion, silencing HIF-1α gene could aggravate growth inhibition and necrosis of PTEC under hypoxia. We provide evidence, from the opposite direction, that HIF-1 activation under hypoxia may facilitate adaptation and survival of proximal renal tubular cells, and the beneficial effects may be related to its downstream genes, such as Glut-1 and VEGF.

Silencing HIF-1α reduces the adhesion and secretion functions of acute leukemia hBMSCs

Hypoxia inducible factor-1α (HIF-1α) is an important transcription factor, which plays a critical role in the formation of solid tumor and its microenvironment. The objective of the present study was to evaluate the expression and function of HIF-1α in human leukemia bone marrow stromal cells (BMSCs) and to identify the downstream targets of HIF-1α. HIF-1α expression was detected at both the RNA and protein levels using real-time PCR and immunohistochemistry, respectively. Vascular endothelial growth factor (VEGF) and stromal cell-derived factor-1α (SDF-1α) were detected in stromal cells by enzyme-linked immunosorbent assay. HIF-1α was blocked by constructing the lentiviral RNAi vector system and infecting the BMSCs. The Jurkat cell/BMSC co-cultured system was constructed by putting the two cells into the same suitable cultured media and conditions. Cell adhesion and secretion functions of stromal cells were evaluated after transfection with the lentiviral RNAi vector of HIF-1α. Increased HIF-1α mRNA and protein was detected in the nucleus of the acute myeloblastic and acute lymphoblastic leukemia compared with normal BMSCs. The lentiviral RANi vector for HIF-1α was successfully constructed and was applied to block the expression of HIF-1α. When HIF-1α of BMSCs was blocked, the expression of VEGF and SDF-1 secreted by stromal cells were decreased. When HIF-1α was blocked, the co-cultured Jurkat cell's adhesion and migration functions were also decreased. Taken together, these results suggest that HIF-1α acts as an important transcription factor and can significantly affect the secretion and adhesion functions of leukemia BMSCs.

Visualization and in vivo tracking of the exosomes of murine melanoma B16-BL6 cells in mice after intravenous injection

The development of exosomes as delivery vehicles requires understanding how and where exogenously administered exosomes are distributed in vivo. In the present study, we designed a fusion protein consisting of Gaussia luciferase and a truncated lactadherin, gLuc-lactadherin, and constructed a plasmid expressing the fusion protein. B16-BL6 murine melanoma cells were transfected with the plasmid, and exosomes released from the cells were collected by ultracentrifugation. Strong luciferase activity was detected in the fraction containing exosomes, indicating their efficient labeling with gLuc-lactadherin. Then, the labeled B16-BL6 exosomes were intravenously injected into mice, and their tissue distribution was evaluated. Pharmacokinetic analysis of the exosome blood concentration-time profile revealed that B16-BL6 exosomes disappeared very quickly from the blood circulation with a half-life of approximately 2min. Little luciferase activity was detected in the serum at 4h after exosome injection, suggesting rapid clearance of B16-BL6 exosomes in vivo. Moreover, sequential in vivo imaging revealed that the B16-BL6 exosome-derived signals distributed first to the liver and then to the lungs. These results indicate that gLuc-lactadherin labeling is useful for tracing exosomes in vivo and that B16-BL6 exosomes are rapidly cleared from the blood circulation after systemic administration.

Small interfering RNA targeting HIF-1α reduces hypoxia-dependent transcription and radiosensitizes hypoxic HT 1080 human fibrosarcoma cells in vitro

BACKGROUND

Hypoxia inducible factor-1 has been identified as a potential target to overcome hypoxia-induced radioresistance The aim of the present study was to investigate whether selective HIF-1 inhibition via small interfering RNA (siRNA) targeting hypoxia-inducible factor 1α (HIF-1α) affects hypoxia-induced radioresistance in HT 1080 human fibrosarcoma cells.

MATERIAL AND METHODS

HIF-1α expression in HT 1080 human fibrosarcoma cells in vitro was silenced using HIF-1α siRNA sequence primers. Quantitative real-time polymerase chain reaction assay was performed to quantify the mRNA expression of HIF-1α. HIF-1α protein levels were studied by Western blotting at 20% (air) or after 12 hours at 0.1% O2 (hypoxia). Cells were assayed for clonogenic survival after irradiation with 2, 5, or 10 Gy, under normoxic or hypoxic conditions in the presence of HIF-1α-targeted or control siRNA sequences. A modified oxygen enhancement ratio (OER´) was calculated as the ratio of the doses to achieve the same survival at 0.1% O(2) as at ambient oxygen tensions. OER´ was obtained at cell survival levels of 50%, 37%, and 10%.

RESULTS

HIF-1α-targeted siRNA enhanced radiation treatment efficacy under severely hypoxic conditions compared to tumor cells treated with scrambled control siRNA. OER was reduced on all survival levels after treatment with HIF-1α-targeted siRNA, suggesting that inhibition of HIF-1 activation by using HIF-1α-targeted siRNA increases radiosensitivity of hypoxic tumor cells in vitro.

CONCLUSION

Inhibition of HIF-1 activation by using HIF-1α-targeted siRNA clearly acts synergistically with radiotherapy and increase radiosensitivity of hypoxic cells in vitro.

Role and mechanism of hypoxia-inducible factor-1 in cell growth and apoptosis of breast cancer cell line MDA-MB-231

The role of hypoxia-inducible factor-1 (HIF-1) in tumor development and progression is well-established but its effect on tumor growth remains controversial. The present study investigated the effect of HIF-1 on tumor growth using the estrogen receptor-negative breast cancer cell line, MDA-MB-231. Using Western blotting, we detected a higher level of HIF-1α protein in MDA-MB-231 cells than in any other breast cancer cell lines analyzed, and this was accompanied by a more rapid growth pattern. Interruption of HIF-1α expression using small interference RNA (siRNA) significantly suppressed cell growth and increased apoptosis, but the cell cycle was not affected. Activated fragments with increased caspase 3 activity and a mobility shift of B cell lymphoma (Bcl-2) were also detected in cells treated with HIF-1α siRNA. HIF-1 allows breast cancer cells to grow under long-term serum deprivation by inactivation of the caspase cascade and thus inhibition of apoptosis. Blocking HIF-1α protein resulted in loss of Bcl-2 function, which may contribute to the activation of the caspase cascade.

RNAi reduces expression and intracellular retention of mutant cartilage oligomeric matrix protein

Mutations in cartilage oligomeric matrix protein (COMP), a large extracellular glycoprotein expressed in musculoskeletal tissues, cause two skeletal dysplasias, pseudoachondroplasia and multiple epiphyseal dysplasia. These mutations lead to massive intracellular retention of COMP, chondrocyte death and loss of growth plate chondrocytes that are necessary for linear growth. In contrast, COMP null mice have only minor growth plate abnormalities, normal growth and longevity. This suggests that reducing mutant and wild-type COMP expression in chondrocytes may prevent the toxic cellular phenotype causing the skeletal dysplasias. We tested this hypothesis using RNA interference to reduce steady state levels of COMP mRNA. A panel of shRNAs directed against COMP was tested. One shRNA (3B) reduced endogenous and recombinant COMP mRNA dramatically, regardless of expression levels. The activity of the shRNA against COMP mRNA was maintained for up to 10 weeks. We also demonstrate that this treatment reduced ER stress. Moreover, we show that reducing steady state levels of COMP mRNA alleviates intracellular retention of other extracellular matrix proteins associated with the pseudoachondroplasia cellular pathology. These findings are a proof of principle and the foundation for the development of a therapeutic intervention based on reduction of COMP expression.

Control of hypoxia-induced tumor cell adhesion by cytophilic human catalase

Hypoxia-induced reactive oxygen species (ROS)-mediated expression of a variety of genes in endothelial cells has been suggested to be involved in abnormal cell adhesion. To prevent this by accelerated binding of catalase to endothelial cells, human catalase (hCAT), an enzyme catalyzing the decomposition of hydrogen peroxide, was fused with three repeats of arginine-glycine-aspartic acid peptide or nona arginine peptide at the C-terminal to obtain hCAT-(RGD)3 and hCAT-R9, respectively. Human CAT and its derivatives were expressed in yeast Pichia pastoris and purified. The specific activity and secondary structure of hCAT-(RGD)3 and hCAT-R9 were close to those of hCAT, but these derivatives showed higher binding to the mouse aortic vascular endothelial cell line MAEC than hCAT, indicating that they are cytophilic derivatives. Hypoxic treatment of MAEC increased the intracellular ROS level, the binding of mouse melanoma cells, and the activity of transcription factors, hypoxia inducible factor-1 and nuclear factor-kappaB. hCAT-(RGD)3 or hCAT-R9 efficiently inhibited these changes compared with hCAT. These results indicate that cytophilic hCAT-(RGD)3 and hCAT-R9 are effective in inhibiting hypoxia-induced tumor cell adhesion to endothelial cells.

Nonviral vector-mediated RNA interference: its gene silencing characteristics and important factors to achieve RNAi-based gene therapy

RNA interference (RNAi) is a potent and specific gene silencing event in which small interfering RNA (siRNA) degrades target mRNA. Therefore, RNAi is of potential use as a therapeutic approach for the treatment of a variety of diseases in which aberrant expression of mRNA causes a problem. RNAi can be achieved by delivering siRNA or vectors that transcribe siRNA or short-hairpin RNA (shRNA). The aim of this review is to examine the potential of nonviral vector-mediated RNAi technology in treating diseases. The characteristics of plasmid DNA expressing shRNA were compared with those of siRNA, focusing on the duration of gene silencing, delivery to target cells and target specificity. Recent progresses in prolonging the RNAi effect, improving the delivery to target cells and increasing the specificity of RNAi in vivo are also reviewed.

Association of hypoxia-inducible factor-1 expression with histology in epithelial ovarian tumors: a quantitative analysis of HIF-1

BACKGROUND

Hypoxia-inducible factor-1 (HIF-1) is an essential transcription factor that mediates cellular and systemic homeostatic responses to reduced oxygen availability in mammals. So far, using immunohistochemistry we have analyzed the association of HIF-1alpha expression with histological type among epithelial ovarian tumors. In the present study, quantitative analyses of activated HIF-1 level in the nucleus and of accumulated HIF-1alpha level in the cytoplasm were performed to clarify whether or not the hypoxic state would be correlated to histology, malignancy, and tumor size in epithelial ovarian tumors.

METHOD

HIF-1 level in the nucleus was analyzed using DNA binding assay, and HIF-1alpha level in the cytoplasm was measured by ELISA for a total of 36 epithelial ovarian tumors as follows: 5 serous adenocarcinomas (SEAs), 7 clear cell adenocarcinomas (CLAs), 7 endometrioid adenocarcinomas (ENAs), 4 mucinous adenocarcinomas (MUAs), 2 mucinous borderline tumors (MBTs), and 11 mucinous adenomas.

RESULTS

HIF-1 level (mg/ml) in the nucleus and HIF-1alpha level (mg/ml) in the cytoplasm were on average 0.116 and 0.178 for SEAs, 0.328 and 0.306 for CLAs, 0.171 and 0.305 for ENAs, 0.097 and 0.176 for MUAs, 0.224 and 0.180 for mucinous borderline tumors, 0.152 and 0.154 for mucinous adenomas. CLAs showed the highest levels for both of HIF-1 and HIF-1alpha, while MUAs showed the lowest levels of both. Mucinous adenomas were higher in HIF-1 than MUAs.

CONCLUSION

Hypoxic state was considered to be closely related to histological type of epithelial ovarian tumors, suggesting that CLAs may be most hypoxic. In the comparison of mucinous tumors, malignancies would not always become most hypoxic. Tumor size may not be strongly associated with hypoxic state.

Molecular composition, activation mechanism of hypoxia-inducible factor-1 and targeted therapy of hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most common malignant tumor in the world, with a complex process involving multi-center, multi-cause and multi-genes. Surgical resection is still the main treatment. However, the diagnosis of HCC mostly occurs at middle or advanced stage, and the prognosis is very poor. Therefore, the development of a novel molecular marker for early diagnosis and a new target for gene therapy become hot spots. Hypoxia-inducible factor-1 (HIF-1) takes part in the development, metastasis and recurrence of HCC, and it has potential applications in the early diagnosis and molecular targeted therapy of HCC. We presented a review on molecular composition, activation mechanism of HIF-1, and the targeted therapeutic approaches applied to hepatocellular carcinoma.

Enhancement of antiproliferative activity of interferons by RNA interference-mediated silencing of SOCS gene expression in tumor cells

The suppressor of cytokine signaling (SOCS) proteins, negative regulators of interferon (IFN)-induced signaling pathways, is involved in IFN resistance of tumor cells. To improve the growth inhibitory effect of IFN-beta and IFN-gamma on a murine melanoma cell line, B16-BL6, and a murine colon carcinoma cell line, Colon26 cells, SOCS-1 and SOCS-3 gene expression in tumor cells was downregulated by transfection of plasmid DNA expressing short hairpin RNA targeting one of these genes (pshSOCS-1 and pshSOCS-3, respectively). Transfection of pshSOCS-1 significantly increased the antiproliferative effect of IFN-gamma on B16-BL6 cells. However, any other combinations of plasmids and IFN had little effect on the growth of B16-BL6 cells. In addition, transfection of pshSOCS-1 and pshSOCS-3 produced little improvement in the effect of IFN on Colon26 cells. To understand the mechanism underlining these findings, the level of SOCS gene expression was measured by real time polymerase chain reaction. Addition of IFN-gamma greatly increased the SOCS-1 mRNA expression in B16-BL6 cells. Taking into account the synergistic effect of pshSOCS-1 and IFN-gamma on the growth of B16-BL6 cells, these findings suggest that IFN-gamma-induced high SOCS-1 gene expression in B16-BL6 cells significantly interferes with the antiproliferative effect of IFN-gamma. These results indicate that silencing SOCS gene expression can be an effective strategy to enhance the antitumor effect of IFN under conditions in which the SOCS gene expression is upregulated by IFN.