Ex vivo culture of head and neck cancer explants in cell sheet for testing chemotherapeutic sensitivity

PURPOSE

Tumor explant culture systems can mimic the in vivo tumor microenvironment, proposing as a substitute for preclinical studies for prediction of individual treatment response. Therefore, our study evaluated the potential usefulness of ex vivo tumor explants culture assembled into the cell sheets by anticancer drug screening in patients with head and neck squamous cell carcinoma (HNSCC).

METHODS

Our model included tumor explants incorporated into cell sheet composing of epithelium and subepithelial stroma using tumor and mucosal samples obtained from the HNSCC patients who underwent surgery. Cell growth, viability, and hypoxia were measured by cell counting kit-8, live/dead assay, propidium iodide, and LOX-1 staining, and were compared among the different treatment groups with vehicle, cisplatin or docetaxel.

RESULTS

Tumor explants stably survived in the cell sheet over 10 days after explantation, whereas most of the explants in non-matrix culture became nonviable within 5-8 days with the significant daily decrease of viability. The live tissue areas of tumor explants in the cell sheet maintained over 30 days without significant changes although hypoxic cell areas gradually increased up to 5 days. Tissue viability and live cancer tissue areas significantly decreased after the treatment of cisplatin or docetaxel in the dose and time-dependent manners.

CONCLUSION

Our cell sheet-based tumor explants model might be applied to the reliable ex vivo screening for anticancer chemotherapeutics for HNSCC.

Melatonin inhibits Warburg-dependent cancer by redirecting glucose oxidation to the mitochondria: a mechanistic hypothesis

Melatonin has the ability to intervene in the initiation, progression and metastasis of some experimental cancers. A large variety of potential mechanisms have been advanced to describe the metabolic and molecular events associated with melatonin's interactions with cancer cells. There is one metabolic perturbation that is common to a large number of solid tumors and accounts for the ability of cancer cells to actively proliferate, avoid apoptosis, and readily metastasize, i.e., they use cytosolic aerobic glycolysis (the Warburg effect) to rapidly generate the necessary ATP required for the high metabolic demands of the cancer cells. There are several drugs, referred to as glycolytic agents, that cause cancer cells to abandon aerobic glycolysis and shift to the more conventional mitochondrial oxidative phosphorylation for ATP synthesis as in normal cells. In doing so, glycolytic agents also inhibit cancer growth. Herein, we hypothesize that melatonin also functions as an inhibitor of cytosolic glycolysis in cancer cells using mechanisms, i.e., downregulation of the enzyme (pyruvate dehydrogenase kinase) that interferes with the conversion of pyruvate to acetyl CoA in the mitochondria, as do other glycolytic drugs. In doing so, melatonin halts the proliferative activity of cancer cells, reduces their metastatic potential and causes them to more readily undergo apoptosis. This hypothesis is discussed in relation to the previously published reports. Whereas melatonin is synthesized in the mitochondria of normal cells, we hypothesize that this synthetic capability is not present in cancer cell mitochondria because of the depressed acetyl CoA; acetyl CoA is necessary for the rate limiting enzyme in melatonin synthesis, arylalkylamine-N-acetyltransferase. Finally, the ability of melatonin to switch glucose oxidation from the cytosol to the mitochondria also explains how tumors that become resistant to conventional chemotherapies are re-sensitized to the same treatment when melatonin is applied.

DCLK1 inhibition attenuates tumorigenesis and improves chemosensitivity in esophageal squamous cell carcinoma by inhibiting β-catenin/c-Myc signaling

Doublecortin-like kinase 1 (DCLK1) is involved in tumorigenesis, tumor growth and metastasis, and epithelial-to-mesenchymal transition in many digestive tract tumors. It is reportedly highly expressed in Barrett's esophagus and esophageal adenocarcinoma, but its effects on the occurrence and progression of esophageal squamous cell carcinoma (ESCC) remain unclear. In this study, real-time PCR and western blot analysis confirmed significant upregulation of DCLK1 expression in human ESCC tissues and cell lines. CCK-8 assay showed that transfection with siRNA against DCLK1 (si-DCLK1) markedly inhibited cell proliferation and colony formation in the ESCC cell lines Eca109 and TE1. Transwell assay revealed that si-DCLK1 transfection inhibited the migratory and invasive capacities of Eca109 and TE1 cells. Moreover, si-DCLK1 increased the chemosensitivity of these cells to cisplatin, as indicated by inhibited cell viability and colony formation, and increased ROS and apoptosis in cisplatin-treated cells. Western blot assay revealed that expression of nuclear β-catenin and c-Myc was significantly increased in ESCC tissues and that si-DCLK1 markedly downregulated nuclear β-catenin and c-Myc in Eca109 cells. Treatment with lithium chloride, an activator of β-catenin signaling, partially abolished the si-DCLK1-induced inhibition of proliferation, migration, invasion, and chemoresistance of ESCC cells. These findings suggest that knockdown of DCLK1 may inhibit the progression of ESCC by regulating proliferation, migration, invasion, and chemosensitivity via suppressing the β-catenin/c-Myc pathway, supporting a promising therapeutic target against ESCC.

Three-dimensional culture and clinical drug responses of a highly metastatic human ovarian cancer HO-8910PM cells in nanofibrous microenvironments of three hydrogel biomaterials

Background

Ovarian cancer is a highly aggressive malignant disease in gynecologic cancer. It is an urgent task to develop three-dimensional (3D) cell models in vitro and dissect the cell progression-related drug resistance mechanisms in vivo. In the present study, RADA16-I peptide has the reticulated nanofiber scaffold networks in hydrogel, which is utilized to develop robust 3D cell culture of a high metastatic human ovarian cancer HO-8910PM cell line accompanied with the counterparts of Matrigel and collagen I.

Results

Consequently, HO-8910PM cells were successfully cultivated in three types of hydrogel biomaterials, such as RADA16-I hydrogel, Matrigel, and collagen I, according to 3D cell culture protocols. Designer RADA16-I peptide had well-defined nanofiber networks architecture in hydrogel, which provided nanofiber cell microenvironments analogous to Matrigel and collagen I. 3D-cultured HO-8910PM cells in RADA16-I hydrogel, Matrigel, and collagen I showed viable cell proliferation, proper cell growth, and diverse cell shapes in morphology at the desired time points. For a long 3D cell culture period, HO-8910PM cells showed distinct cell aggregate growth patterns in RADA16-I hydrogel, Matrigel, and collagen I, such as cell aggregates, cell colonies, cell clusters, cell strips, and multicellular tumor spheroids (MCTS). The cell distribution and alignment were described vigorously. Moreover, the molecular expression of integrin β1, E-cadherin and N-cadherin were quantitatively analyzed in 3D-cultured MCTS of HO-8910PM cells by immunohistochemistry and western blotting assays. The chemosensitivity assay for clinical drug responses in 3D context indicated that HO-8910PM cells in three types of hydrogels showed significantly higher chemoresistance to cisplatin and paclitaxel compared to 2D flat cell culture, including IC₅₀ values and inhibition rates.

Conclusion

Based on these results, RADA16-I hydrogel is a highly competent, high-profile, and proactive nanofiber scaffold to maintain viable cell proliferation and high cell vitality in 3D cell models, which may be particularly utilized to develop useful clinical drug screening platform in vitro.

MiR-142-3p enhances chemosensitivity of breast cancer cells and inhibits autophagy by targeting HMGB1

MiR-142-3p has been reported to act as a tumor suppressor in breast cancer. However, the regulatory effect of miR-142-3p on drug resistance of breast cancer cells and its underlying mechanism remain unknown. Here, we found that miR-142-3p was significantly downregulated in the doxorubicin (DOX)-resistant MCF-7 cell line (MCF-7/DOX). MiR-142-3p overexpression increased DOX sensitivity and enhanced DOX-induced apoptosis in breast cancer cells. High-mobility group box 1 (HMGB1) is a direct functional target of miR-142-3p in breast cancer cells and miR-142-3p negatively regulated HMGB1 expression. Moreover, overexpression of HMGB1 dramatically reversed the promotion of apoptosis and inhibition of autophagy mediated by miR-142-3p up-regulation. In conclusion, miR-142-3p overexpression may inhibit autophagy and promote the drug sensitivity of breast cancer cells to DOX by targeting HMGB1. The miR-142-3p/HMGB1 axis might be a novel target to regulate the drug resistance of breast cancer patients.

Administration with hyperoside sensitizes breast cancer cells to paclitaxel by blocking the TLR4 signaling

Breast cancer is a malignancy and one of the most frequent causes of cancer death among women worldwide. Paclitaxel is a common chemotherapeutic drug and has recently been shown to facilitate tumor cell escape during cytotoxic chemotherapy by inducing inflammatory mediators and pro-survival protein expression. Hyperoside is a flavonoid glycoside compound and exerts anti-inflammation, and anti-tumor growth properties. However, its function in breast cancer chemosensitivity remains poorly elucidated. In this study, hyperoside exhibited little cytotoxicity to normal human breast mammary epithelial cell lines, and also protected against paclitaxel-induced cytotoxicity in MCF-10A. Importantly, treatment with hyperoside engendered not only inhibition of cell viability, but also potentiated cancer cell sensitivity to paclitaxel in TLR4-positive breast cancer MDA-MB-231 cells by suppressing cell viability, and increasing cell apoptosis and caspase-3 activity. Nevertheless, although hyperoside exposure restrained cell viability, its treatment presented little effects to paclitaxel sensitivity in TLR4-null HCC1806 cells. Intriguingly, paclitaxel stimulation activated the TLR4-NF-κB signaling, which was reversed after hyperoside administration. Concomitantly, hyperoside also attenuated paclitaxel-mediated anti-apoptotic Bcl-2 expression, but enhanced the effects of paclitaxel on pro-apoptotic Bax expression, and pro-inflammatory cytokine IL-6 and IL-6 levels in MDA-MB-231 cells. Importantly, restoring the TLR4 pathway overturned hyperoside-evoked chemosensitivity to paclitaxel in MDA-MB-231 cells. Thus, hyperoside may elevate breast cancer cell sensitivity to paclitaxel by blocking TLR4 activation-mediated pro-inflammatory and pro-survival approaches, thereby endorsing its usefulness as a promising therapeutic combination to overcome chemosensitivity in breast cancer.

Benefit of buspirone on chemoreflex and central apnoeas in heart failure: a randomized controlled crossover trial

AIMS

Increased chemosensitivity to carbon dioxide (CO₂ ) is an important trigger of central apnoeas (CA) in heart failure (HF), with negative impact on outcome. We hypothesized that buspirone, a 5HT_1A receptor agonist that inhibits serotonergic chemoreceptor neuron firing in animals, can decrease CO₂ chemosensitivity and CA in HF.

METHODS AND RESULTS

The BREATH study was a randomized, double-blind, placebo-controlled, crossover study (EudraCT-code 2015-005383-42). Outpatients with systolic HF (left ventricular ejection fraction <50%) and moderate-severe CA [nocturnal apnoea-hypopnoea index (AHI) ≥15 events/h] were randomly assigned to either oral buspirone (15 mg thrice daily) or placebo for 1 week, with a crossover design (1 week of wash-out). The primary effectiveness endpoint was a decrease in CO₂ chemosensitivity >0.5 L/min/mmHg. The primary safety endpoint was freedom from serious adverse events. Sixteen patients (age 71.3 ± 5.8 years, all males, left ventricular ejection fraction 29.8 ± 7.8%) were enrolled. In the intention-to-treat analysis, more patients treated with buspirone (8/16, 50%) had a CO₂ chemosensitivity reduction >0.5 L/min/mmHg from baseline than those treated with placebo (1/16, 6.7%) (difference between groups 43%, 95% confidence interval 14-73%, P = 0.016). Buspirone compared to baseline led to a 41% reduction in CO₂ chemosensitivity (P = 0.001) and to a reduction in the AHI, central apnoea index and oxygen desaturation index of 42%, 79%, 77% at nighttime and 50%, 78%, 86% at daytime (all P < 0.01); no difference was observed after placebo administration (all P > 0.05). No patient reported buspirone-related serious adverse events.

CONCLUSIONS

Buspirone reduces CO₂ chemosensitivity and improves CA and oxygen saturation across the 24 h in patients with HF.

Clinical value of serum squamous cell carcinoma antigen levels in predicting chemosensitivity, lymph node metastasis, and prognosis in patients with cervical squamous cell carcinoma

Background

Our aim was to investigate the value of serum squamous cell carcinoma (SCC) antigen levels in predicting chemosensitivity, lymph node metastasis, as well as prognosis in patients with cervical squamous cell carcinoma who received neoadjuvant chemotherapy (NACT).

Methods

This retrospective study enrolled 103 patients with cervical squamous cell carcinoma and then compared the SCC antigen levels between patients who underwent NACT followed by radical surgery (NACT group) and those who underwent radical surgery alone (conventional group), and a correlation analysis between SCC antigen levels and chemosensitivity, lymph node metastasis, or survival time was conducted.

Results

The SCC antigen levels changed after NACT and were associated with chemosensitivity. Moreover, the optimal cut-off value of the percentage decrease in SCC antigen level after the first chemotherapy (FSCC (%)) was 42.0%, which could be used for assessment of chemosensitivity. The rate of positive lymph nodes in patients with pretreatment SCC antigen levels ≥3.9 ng/mL was significantly decreased after NACT. The overall survival (OS) of NACT group was significantly longer than that of conventional group when the pretreatment SCC antigen levels were ≥ 4.55 ng/mL. The OS and progression-free survival rates of patients with SCC antigen levels < 2.7 ng/mL were longer than those ≥2.7 ng/mL after the first chemotherapy.

Conclusions

The 42.0% of FSCC (%) after NACT is a reliable indicator of chemosensitivity. Pretreatment and posttreatment SCC antigen levels can be used in evaluating the lymph node metastases and prognosis of patients with cervical squamous cell carcinoma.

6-Shogaol enhances the anticancer effect of 5-fluorouracil, oxaliplatin, and irinotecan via increase of apoptosis and autophagy in colon cancer cells in hypoxic/aglycemic conditions

Background

The development and growth of colorectal cancer based on constitutive activation of numerous signaling pathways that stimulate proliferation and metastasis. Plant-derived agents excel by targeting multiple aspects of tumor progression. Previous investigations have shown that ginger derivatives- shogaols possess anti-cancer and anti-inflammatory effects. In the present study, we have examined the anti-cancer effects of 6-shogaol alongside with the most widely used chemotherapeutic agents/regimens in the tumor-like microenvironment conditions.

Methods

Cytotoxicity on two colon cancer cell lines (SW480 and SW620) was measured by MTT test. Apoptosisassay, immunocytochemical and Western blotting analysis for autophagy and apoptosis detection were performed.

Results

Here, we report that 6-shogaol by itself or in combination with chemotherapeutic agents/regimens exerted a cytotoxic effect on CRC cells. Cell death might be linked with the activation of autophagy and apoptosis-related pathways. In the tumor-like microenvironment, which is characterized by hypoxia and glucose starvation, 6-shogaol with chemotherapeutics is significantly more potent than conventional chemotherapy alone.

Conclusions

Collectively, our data suggest that the addition of 6-shogaol to established chemotherapeutic regimens could potentially be a remarkable therapeutic strategy for colorectal cancer.

Extracellular biophysical environment: Guilty of being a modulator of drug sensitivity in ovarian cancer cells

The roles of the extracellular biophysical environment in cancer are barely studied. This study considers the possibility that cell-like topography of a cancer cell environment may influence chemo-responses. Here, a novel bioimprinting technique was employed to produce cell-like topography on the polystyrene substrates used for cell culture. In this work, we have shown that extracellular biophysical cues generated from the topography alter the chemosensitivity of ovarian cancer cells. The three-dimensionality of the bioimprinted surface altered the cell-surface interaction, which consequently modulated intracellular signalling and chemoresponses. Sensitivity to platinum was altered more than that to paclitaxel. The effect was largely mediated through the integrin/focal adhesion system and the Rho/ROCK pathway. Moreover, the results provided evidence that biophysical cues also modulate MAPK signalling associated with chemo-resistance in ovarian cancer. Therefore, the novel findings from of this study revealed for the first time that the effects of the biophysical environment, such as substrate topography, influences ovarian cancer cell responses to clinical drugs. These observations suggest that a full clinical understanding of ovarian cancer will include biophysical aspects of tumour microenvironment.

Pegylated liposomal doxorubicin in patients with metastatic triple-negative breast cancer: 8-year experience of a single center

BACKGROUND

The known efficacy of doxorubicin in metastatic breast cancer is countered by its dose-limiting myelosuppression and cardiotoxicity. Pegylated liposomal doxorubicin (PLD) was discovered to overcome these problems. But the data regarding its use in metastatic TNBC (triple-negative breast cancer) is still insufficient. Our study aimed to assess the factors affecting the outcome of the patients with metastatic TNBC who received PLD.

RESULTS

During a period of 8 years (January 2011-December 2018), we analyzed 39 eligible patients. The disease control rate (DCR) was 51.3%. Among all the analyzed factors, two of them significantly affected DCR. The first factor was the chemosensitivity to prior anthracycline. As patients with chemosensitive disease had higher DCR than those with the chemoresistant disease (P = .001). The second factor was the number of prior lines of chemotherapy. As the patients who received two prior lines had a higher DCR than those who received three lines or more (P = .023). Chemosensitivity was the only significant independent factor for DCR (odds ratio = .095, P = .008). For the studied patients, the median progression-free survival (PFS) was 7 months. The anthracycline-chemosensitivity was the only significant independent prognostic factor for PFS (P = .002). The median overall survival (OS) was 12 months. There was a marginally significant effect of anthracycline-chemosensitivity on OS (P = .052).

CONCLUSION

The anthracycline-chemosensitivity is an independent predictive and prognostic factor for the patients with metastatic TNBC receiving PLD. In developing countries, PLD should be reserved for the patients whose tumors are anthracycline-chemosensitive.

Targeting TJP1 attenuates cell-cell aggregation and modulates chemosensitivity against doxorubicin in leiomyosarcoma

Tight junction protein 1 (TJP1) is a membrane-associated cytosolic protein important for cell-cell communication in intercellular barriers in epithelial and non-epithelial cells. Here, we explored the functional involvement of TJP1 in non-epithelial tumors such as soft tissue sarcoma, especially in leiomyosarcoma (LMS). TJP1 expression in soft tissue sarcoma was analyzed in normal and tumor tissues as well as from public datasets such as the TCGA provisional dataset, in which TJP1 expression was compared with other subtypes such as undifferentiated sarcomas, and myxofibrosarcomas. SK-LMS-1 cell lines with reduced TJP1 expression showed attenuated anchorage-independent colony formation as well as reduced intercellular aggregation on non-coated culture plates compared with control as well as parental SK-LMS-1 cells. Transcriptome profiling following TJP1 knockdown in SK-LMS-1 cells suggested the involvement of several signaling pathways, including NF-κB pathway and growth factor receptor signaling. In addition, TJP1 downregulation induced enhanced response against anti-cancer agents, doxorubicin and gefitinib. Taken together, these results suggest that TJP1 contributes to sarcoma genesis and might be useful therapeutic target. KEY MESSAGES: • TJP1 expression at RNA level higher in tumor than in normal tissues of sarcoma. • Targeting TJP1 attenuates cell-cell aggregation and anchorage-independent growth. • Targeting TJP1 is beneficial in anti-cancer therapy in LMS.

The Influence of Bcl-3 Expression on Cell Migration and Chemosensitivity of Gastric Cancer Cells via Regulating Hypoxia-Induced Protective Autophagy

Purpose

Gastric cancer is a highly metastatic malignant tumor, often characterized by chemoresistance and high mortality. In the present study, we aimed to investigate the role of B-cell lymphoma 3 (Bcl-3) protein on cell migration and chemosensitivity of gastric cancer.

Materials and Methods

The gastric cancer cell lines, AGS and NCI-N87, were used for the in vitro studies and the in vivo studies were performed using BALB/c nude mice. Western blotting, wound healing assay, Cell Counting Kit-8 assay, immunohistochemistry, and terminal deoxynucleotidyl transferase dUTP nick end labeling assay were used to evaluate the role of Bcl-3 in gastric cancer.

Results

We found that the protein expression of hypoxia (HYP)-inducible factor-1α and Bcl-3 were markedly upregulated under hypoxic conditions in both AGS and NCI-N87 cells in a time-dependent manner. Interestingly, small interfering RNA-mediated knockdown of Bcl-3 expression affected the migration and chemosensitivity of the gastric cancer cells. AGS and NCI-N87 cells transfected with si-RNA-Bcl-3 (si-Bcl-3) showed significantly reduced migratory ability and increased chemosensitivity to oxaliplatin, 5-fluorouracil, and irinotecan. In addition, si-Bcl-3 restored the autophagy induced by HYP. Further, the protective role of si-Bcl-3 on the gastric cancer cells could be reversed by the autophagy inducer, rapamycin. Importantly, the in vivo xenograft tumor experiments showed similar results.

Conclusions

Our present study reveals that Bcl-3 knockdown inhibits cell migration and chemoresistance of gastric cancer cells through restoring HYP-induced autophagy.

Astragaloside IV enhances cisplatin chemosensitivity in hepatocellular carcinoma by suppressing MRP2

Decreased chemosensitivity among tumor cells is often an obstacle in cisplatin (Cis) chemotherapy. Overexpression of multidrug resistance-associated protein 2 (MRP2) is a key mechanism underlying decreased Cis chemosensitivity and resistance. Astragaloside IV (AS IV) is an important component derived from the well-known traditional Chinese herb Astragalus membranaceus. The aim of this study was to explore the role of AS IV in enhancing the antitumor effect of Cis by suppressing MRP2 expression in HepG2 cells and H22 tumor-bearing mice. After co-treatment of HepG2 cells with Cis and AS IV, we assessed the effects on cell proliferation and apoptosis. Tumor growth and apoptosis assessment were performed to assess chemosensitivity in H22 tumor-bearing mice. We used western blotting, immunofluorescence assays, and immunohistochemistry assays to detect MRP2 expression in HepG2 cells, H22 tumor tissues and mouse kidney tissues. AS IV enhanced Cis chemosensitivity by increasing tumor cell apoptosis and slowing tumor growth in vitro and in vivo. MRP2 overexpression in tumor cells was induced by Cis, which contributes to decreased chemosensitivity and Cis resistance. Co-administration of AS IV suppressed MRP2 expression in tumor tissues, which might be an important mechanism for enhancing Cis chemosensitivity in hepatocellular carcinoma. Moreover, AS IV alleviated Cis-induced kidney injury in mice without changing MRP2 expression. In total, AS IV enhanced the antitumor effect of Cis against hepatocellular carcinoma by suppressing MRP2 expression in tumor cells. The results provide a new insight into the combined use of a chemotherapy drug and natural ingredients to treat cancer.

Decreased excitability of locus coeruleus neurons during hypercapnia is exaggerated in the streptozotocin-model of Alzheimer's disease

The locus coeruleus (LC) is a pontine nucleus important for respiratory control and central chemoreception. It is affected in Alzheimer's disease (AD) and alteration of LC cell function may account for respiratory problems observed in AD patients. In the current study, we tested the electrophysiological properties and CO₂/pH sensitivity of LC neurons in a model for AD. Sporadic AD was induced in rats by intracerebroventricular injection of 2 mg/kg streptozotocin (STZ), which induces behavioral and molecular impairments found in AD. LC neurons were recorded using the patch clamp technique and tested for responses to CO₂ (10% CO₂, pH = 7.0). The majority (~60%) of noradrenergic LC neurons in adult rats were inhibited by CO₂ exposure as indicated by a significant decrease in action potential (AP) discharge to step depolarizations. The STZ-AD rat model had a greater sensitivity to CO₂ than controls. The increased CO₂-sensitivity was demonstrated by a significantly stronger inhibition of activity during hypercapnia that was in part due to hyperpolarization of the resting membrane potential. Reduction of AP discharge in both groups was generally accompanied by lower LC network activity, depolarized AP threshold, increased AP repolarization, and increased current through a subpopulation of voltage-gated K⁺ channels (K_V). The latter was indicated by enhanced transient K_V currents particularly in the STZ-AD group. Interestingly, steady-state K_V currents were reduced under hypercapnia, a change that would favor enhanced AP discharge. However, the collective response of most LC neurons in adult rats, and particularly those in the STZ-AD group, was inhibited by CO₂.

ATG5 regulates mesenchymal stem cells differentiation and mediates chemosensitivity in acute myeloid leukemia

Autophagy is related to the development of several tumors including acute myeloid leukemia (AML). Inhibition of autophagy in AML cells can make them more susceptible to chemotherapy. However, the influence of autophagy in mesenchymal stem cells (MSCs) remains inconclusive. In the present study, we demonstrated that the expression of ATG5 and autophagy were elevated in MSCs derived from AML patients (AML-MSCs) compared to healthy donors (HD-MSCs). After inhibiting autophagy by 3-Methyladenine (3 MA) or silencing ATG5, the differentiation potential of AML-MSCs was decreased, the fraction of G0/G1 phase was increased while that of G2 phase was reduced, and the expression of CXCL12 was reduced in AML-MSCs. After co-culture of NB4 and THP1 with MSCs pretreated with 3 MA or ATG5 knockdown respectively, the sensitivity of AML cell lines to daunorubicin and doxorubicin was improved in a dose- and time-dependent manner compared to controls. The increased sensitivity of AML cells to genotoxic agents was related to ERK1/2 and AKT pathway. These results suggested ATG5 mediated potential differentiation capacities and cell cycle distribution of AML-MSCs, and targeting autophagy, especially ATG5 in AML-MSCs could improve the chemosensitivity of AML.

Silence of FAM83H-AS1 promotes chemosensitivity of gastric cancer through Wnt/β-catenin signaling pathway

Gastric cancer (GC) is a malignant tumor originated from the epithelium of gastric mucosa, its incidence is second only to lung cancer in China. Chemotherapy is one of the most effective methods to treat GC, but some patients are insensitive to chemotherapeutic drugs, leading to chemotherapy failure. In this study, the expression of FAM83H-AS1 was up-regulated in GC tissues and cell lines, and was related to differentiation, invasion depth and chemotherapy insensitivity of GC patients. FAM83H-AS1 was high-expressed in chemoresistant GC tissues and cell line (SGC7901/R), and silence of FAM83H-AS1 sensitized SGC7901/R cells to cisplatin (CDDP) and 5-fluorouracil (5-FU). In addition, silence of FAM83H-AS1 could inactivate Wnt/β-catenin signaling pathway in SGC7901/R cells. The activating of Wnt/β-catenin signaling pathway reversed the promoting effect of FAM83H-AS1 silence on chemotherapy sensitivity, which meant Wnt/β-catenin signaling pathway mediated the regulation of FAM83H-AS1 on chemotherapy sensitivity in SGC7901/R cells. In conclusion, FAM83H-AS1 is related with the CDDP and 5-FU insensitivity of GC patients, silence of FAM83H-AS1 promotes chemosensitivity of GC through Wnt/β-catenin signaling pathway.

MiR-199a-modified exosomes from adipose tissue-derived mesenchymal stem cells improve hepatocellular carcinoma chemosensitivity through mTOR pathway

Background

MiR-199a-3p (miR-199a) can enhance the chemosensitivity of hepatocellular carcinoma (HCC). Because of the easy degradation of miRNA by direct infusion, effective vehicle-mediated delivery of miR-199a may represent a new strategy for improving HCC chemotherapy. Considering mesenchymal stem cell (MSC)-derived exosomes as promising natural nanovectors for drug and molecule delivery, we aimed to determine whether exosomes from adipose tissue-derived MSCs (AMSCs) could be used to deliver miR-199a and improve HCC chemosensitivity.

Methods

MiR-199a-modified AMSCs (AMSC-199a) were constructed by miR-199a lentivirus infection and puromycin selection. MiR-199-modified exosomes (AMSC-Exo-199a) were isolated from the supernatant of AMSC-199a and were assessed by transmission electron microscopy, nanoparticle tracking analysis, and flow cytometry analysis. The expression levels of miR-199a in HCC samples, AMSCs, exosomes, and HCC cells were quantified by real-time PCR. The effects of AMSC-Exo-199a on HCC chemosensitivity were determined by cell proliferation and apoptosis assays and by i.v. injection into orthotopic HCC mouse models with doxorubicin treatment. MTOR, p-4EBP1 and p-70S6K levels in HCC cells and tissues were quantified by Western blot.

Results

AMSC-Exo-199a had the classic characteristics of exosomes and could effectively mediate miR-199a delivery to HCC cells. Additionally, AMSC-Exo-199a significantly sensitized HCC cells to doxorubicin by targeting mTOR and subsequently inhibiting the mTOR pathway. Moreover, i.v.-injected AMSC-Exo-199a could distribute to tumor tissue and markedly increased the effect of Dox against HCC in vivo.

Conclusions

AMSC-Exo-199a can be an effective vehicle for miR-199a delivery, and they effectively sensitized HCC to chemotherapeutic agents by targeting mTOR pathway. AMSC-Exo-199a administration may provide a new strategy for improving HCC chemosensitivity.

Bioengineered miR-328-3p modulates GLUT1-mediated glucose uptake and metabolism to exert synergistic antiproliferative effects with chemotherapeutics

MicroRNAs (miRNAs or miRs) are small noncoding RNAs derived from genome to control target gene expression. Recently we have developed a novel platform permitting high-yield production of bioengineered miRNA agents (BERA). This study is to produce and utilize novel fully-humanized BERA/miR-328-3p molecule (hBERA/miR-328) to delineate the role of miR-328-3p in controlling nutrient uptake essential for cell metabolism. We first demonstrated successful high-level expression of hBERA/miR-328 in bacteria and purification to high degree of homogeneity (>98%). Biologic miR-328-3p prodrug was selectively processed to miR-328-3p to suppress the growth of highly-proliferative human osteosarcoma (OS) cells. Besides glucose transporter protein type 1, gene symbol solute carrier family 2 member 1 (GLUT1/SLC2A1), we identified and verified large neutral amino acid transporter 1, gene symbol solute carrier family 7 member 5 (LAT1/SLC7A5) as a direct target for miR-328-3p. While reduction of LAT1 protein levels by miR-328-3p did not alter homeostasis of amino acids within OS cells, suppression of GLUT1 led to a significantly lower glucose uptake and decline in intracellular levels of glucose and glycolytic metabolite lactate. Moreover, combination treatment with hBERA/miR-328 and cisplatin or doxorubicin exerted a strong synergism in the inhibition of OS cell proliferation. These findings support the utility of novel bioengineered RNA molecules and establish an important role of miR-328-3p in the control of nutrient transport and homeostasis behind cancer metabolism.

Inhibition of protein FAK enhances 5-FU chemosensitivity to gastric carcinoma via p53 signaling pathways

The small molecule drug 5-fluorouracil (5-FU) is widely used in the treatment for gastric cancer (GC), however, it exerts poor efficacy and is associated with acquired and intrinsic resistance. Focal adhesion kinase (FAK), a non-receptor tyrosine kinase, plays a key role in adhesion, migration, and proliferation of gastric carcinoma cells, suggesting that this kinase may be a promising therapeutic target. Differentially expressed FAK in GC tissue was detected by RT-qPCR and TCGA database analysis. To investigate the biological functions of FAK, loss-of-function experiments were performed. CCK-8 assay, colony formation assay, flow cytometry, dual-luciferase reporter assays, and western blot assays were conducted to determine the underlying mechanisms of FAK in 5-FU chemosensitivity in GC. FAK is overexpressed in GC patients, and positively correlated with poor prognosis. The use of shRNA interference to target FAK decreased proliferation and increased apoptosis of GC cells in vitro. Importantly, FAK silencing enhanced the therapeutic efficacy of 5-FU, leading to reduced tumor growth in vivo. We further demonstrated that FAK silencing increased 5-FU-induced caspase-3 activity, and promoted p53 transcriptional activities. Clinical data also has shown that patients with higher levels of FAK had significantly shorter overall survival (OS) and time to first progression (FP) than those with lower levels of FAK. These findings indicate that FAK plays a critical role in 5-FU chemosensitivity in GC, and the use of FAK inhibitors as an adjunct to 5-FU might be an effective strategy for patients who undergo chemotherapy.

miR-149 inhibits cell proliferation and enhances chemosensitivity by targeting CDC42 and BCL2 in neuroblastoma

Background

Neuroblastoma (NB) is one of most common childhood tumors with high mortality among children worldwide. microRNAs (miRNAs) have been reported to play essential roles in the pathogenesis and therapeutics of NB. However, the role of miR-149 and its mechanism remain poorly understood.

Main methods

The expression levels of miR-149, cell division cycle 42 (CDC42) and B-cell lymphoma 2 (BCL2) were measured in NB tissues or cells by quantitative real-time polymerase chain reaction or western blot. Cell proliferation was measured by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide (MTT) and colony formation assays. Cell apoptosis was detected by flow cytometry. Chemosensitivity of NB cells to doxorubicin (Dox) was analyzed by MTT assay. The interaction between miR-149 and CDC42 or BCL2 was explored by luciferase activity and RNA immunoprecipitation analyses.

Results

Our data indicated that low expression of miR-149 was displayed in NB tissues and cells and associated with poor survival rate. Overexpression of miR-149 inhibited cell proliferation and colony formation but promoted cell apoptosis and chemosensitivity to Dox in NB cells. Moreover, CDC42 and BCL2 were targeted by miR-149. Additionally, CDC42 and BCL2 mRNA levels were elevated in NB tissues and cells and restoration of CDC42 or BCL2 reversed the regulatory effect of miR-149 on NB progression.

Conclusion

Our data suggested that miR-149 suppressed cell proliferation and improved Dox chemosensitivity by regulating CDC42 and BCL2 in NB, providing a novel avenue for treatment of NB.

NOD1 inhibits proliferation and enhances response to chemotherapy via suppressing SRC-MAPK pathway in hepatocellular carcinoma

NOD1 is an innate immune sensor playing an important role in fighting against infection. However, its role in cancer is far from being clarified, and whether NOD1 plays a role in the progression of hepatocellular carcinoma (HCC) has never been reported. Here, we found that NOD1 expression was significantly decreased in hepatocellular carcinoma tissues and overexpression of NOD1 significantly inhibited tumorigenesis in vivo. In vitro experiments demonstrated that NOD1 inhibited proliferation of HCC cells by directly targeting proto-oncogene SRC and inducing cell cycle arrest at G1 phase. Further investigation showed that NOD1 exerted its antitumor effect by inhibiting SRC activation and further suppressing SRC/MAPK axis in hepatocellular carcinoma cells. Moreover, NOD1 dramatically enhanced the response of HCC cells to chemotherapy via inhibition of SRC-MAPK axis both in vitro and in vivo. Collectively, these data indicated that NOD1 suppressed proliferation and enhanced response to sorafenib or 5-FU treatment through inhibiting SRC-MAPK axis in hepatocellular carcinoma. KEY MESSAGES: NOD1 significantly inhibited tumorigenesis of HCC in cellular and animal models. NOD1 inhibited proliferation of HCC cells by inducing cell cycle arrest. NOD1 exerted its antitumor effect on HCC by directly interacting with SRC and inhibiting SRC-MAPK axis. NOD1 significantly enhanced the chemosensitivity of HCC cells to chemotherapeutic drugs.

Human bone marrow-derived mesenchymal stem cell-secreted exosomes overexpressing microRNA-34a ameliorate glioblastoma development via down-regulating MYCN

PURPOSE

Exosomes play important roles in intercellular communication through signaling pathways affecting tumor microenvironment modulation and tumor proliferation, including those in glioblastoma (GBM). As yet, however, limited studies have been conducted on the inhibitory effect of human bone marrow-derived mesenchymal stem cell (hBMSC)-derived exosomes on GBM development. Therefore, we set out to assess the role of hBMSC secreted exosomes, in particular those carrying microRNA-34a (miR-34a), in the development of GBM.

METHODS

Microarray-based expression analysis was employed to identify differentially expressed genes and to predict miRNAs regulating MYCN expression. Next, hBMSCs were transfected with a miR-34a mimic or inhibitor after which exosomes were isolated. Proliferation, apoptosis, migration, invasion and temozolomide (TMZ) chemosensitivity of exosome-exposed GBM cells (T-98G, LN229 and A-172) were measured in vitro. The mechanism underlying MYCN regulation was investigated using lentiviral transfections. The in vivo inhibitory effect of exosomal miR-34a was measured in nude mice xenografted with GBM cells through subcutaneous injection of hBMSCs with an upregulated miR34a content.

RESULTS

We found that poorly-expressed miR-34a specifically targeted and negatively regulated the expression of MYCN in GBM cells. In addition we found that miR-34a was delivered to T-98G, LN229 and A-172 GBM cells via hBMSC-derived exosomes. Exogenous overexpression of miR-34a in hBMSC-derived exosomes resulted in inhibition of GBM cell proliferation, invasion, migration and tumorigenesis in vitro and in vivo, while promoting the chemosensitivity of GBM cells to TMZ by silencing MYCN.

CONCLUSIONS

From our data we conclude that hBMSC-derived exosomes overexpressing miR-34a may be instrumental for the therapeutic targeting and clinical management of GBM.

RASSF1A-Hippo pathway link in patients with urothelial carcinoma of bladder: plausible therapeutic target

RASSF1A is a tumor suppressor gene, and its hypermethylation has been observed in cancers. RASSF1A acts as an upstream regulator of Hippo pathway and modulates its function. The aim of this study was to analyze expression of RASSF1A, Hippo pathway molecules (YAP, MST) and downstream targets (CTGF, Cyr61 and AREG) in bladder cancer patients. Later, the link between RASSF1A and Hippo pathway and a potential therapeutic scope of this link in UBC were also studied. MSPCR was performed to study methylation of RASSF1A promoter. Expression of molecules was studied using qPCR, Western blot and IHC. The link between RASSF1A and Hippo pathway was studied using Spearman's correlation in patients and validated by overexpressing RASSF1A in HT1376 cells and its effect on Hippo pathway was observed using qPCR and Western blot. Further therapeutic potential of this link was studied using MTT and PI assays. The expression of RASSF1A was lower, whereas the expression of YAP, CTGF and CYR61 was higher. The expression of RASSF1A protein gradually decreased, while the expression of YAP, CTGF and CYR61 increased with severity of disease. Based on Spearman's correlation, RASSF1A showed a negative correlation with YAP, CTGF and CYR61. YAP showed a positive correlation with CTGF and CYR61. To validate this link, RASSF1A was overexpressed in HT1376 cells. Overexpressed RASSF1A activated Hippo pathway, followed by a decrease in CTGF and CYR61 at mRNA, and enhanced cytotoxicity to chemotherapeutic drugs. This study finds a previously unrecognized role of RASSF1A in the regulation of CTGF and CYR61 through mediation of Hippo pathway in UBC and supports the significance of this link as a potential therapeutic target for UBC.