Cancer stem cells and drug resistance: the potential of nanomedicine

microRNAs and Acute Myeloid Leukemia Chemoresistance: A Mechanistic Overview

Up until the early 2000s, a functional role for microRNAs (miRNAs) was yet to be elucidated. With the advent of increasingly high-throughput and precise RNA-sequencing techniques within the last two decades, it has become well established that miRNAs can regulate almost all cellular processes through their ability to post-transcriptionally regulate a majority of protein-coding genes and countless other non-coding genes. In cancer, miRNAs have been demonstrated to play critical roles by modifying or controlling all major hallmarks including cell division, self-renewal, invasion, and DNA damage among others. Before the introduction of anthracyclines and cytarabine in the 1960s, acute myeloid leukemia (AML) was considered a fatal disease. In decades since, prognosis has improved substantially; however, long-term survival with AML remains poor. Resistance to chemotherapy, whether it is present at diagnosis or induced during treatment is a major therapeutic challenge in the treatment of this disease. Certain mechanisms such as DNA damage response and drug targeting, cell cycling, cell death, and drug trafficking pathways have been shown to be further dysregulated in treatment resistant cancers. miRNAs playing key roles in the emergence of these drug resistance phenotypes have recently emerged and replacement or inhibition of these miRNAs may be a viable treatment option. Herein, we describe the roles miRNAs can play in drug resistant AML and we describe miRNA-transcript interactions found within other cancer states which may be present within drug resistant AML. We describe the mechanisms of action of these miRNAs and how they can contribute to a poor overall survival and outcome as well. With the precision of miRNA mimic- or antagomir-based therapies, miRNAs provide an avenue for exquisite targeting in the therapy of drug resistant cancers.

Cancer resistance to treatment and antiresistance tools offered by multimodal multifunctional nanoparticles

Chemotherapeutic agents have limited efficacy and resistance to them limits today and will limit tomorrow our capabilities of cure. Resistance to treatment with anticancer drugs results from a variety of factors including individual variations in patients and somatic cell genetic differences in tumours. In front of this, multimodality has appeared as a promising strategy to overcome resistance. In this context, the use of nanoparticle-based platforms enables many possibilities to address cancer resistance mechanisms. Nanoparticles can act as carriers and substrates for different ligands and biologically active molecules, antennas for imaging, thermal and radiotherapy and, at the same time, they can be effectors by themselves. This enables their use in multimodal therapies to overcome the wall of resistance where conventional medicine crash as ageing of the population advance. In this work, we review the cancer resistance mechanisms and the advantages of inorganic nanomaterials to enable multimodality against them. In addition, we comment on the need of a profound understanding of what happens to the nanoparticle-based platforms in the biological environment for those possibilities to become a reality.

Histamine-2 receptor antagonist famotidine modulates cardiac stem cell characteristics in hypertensive heart disease

BACKGROUND

Cardiac stem cells (CSCs) play a vital role in cardiac homeostasis. A decrease in the efficiency of cardiac stem cells is speculated in various cardiac abnormalities. The maintenance of a healthy stem cell population is essential for the prevention of adverse cardiac remodeling leading to cardiac failure. Famotidine, a histamine-2 receptor antagonist, is currently used to treat ulcers of the stomach and intestines. In repurposing the use of the drug, reduction of cardiac hypertrophy and improvement in cardiac function of spontaneously hypertensive rats (SHR) was reported by our group. Given that stem cells are affected in cardiac pathologies, the effect of histamine-2 receptor antagonism on CSC characteristics was investigated.

METHODS

To examine whether famotidine has a positive effect on CSCs, spontaneously hypertensive rats (SHR) treated with the drug were sacrificed; and CSCs isolated from atrial appendages was evaluated. Six-month-old male SHRs were treated with famotidine (30 mg/kg/day) for two months. The effect of famotidine treatment on migration, proliferation and survival of CSCs was compared with untreated SHRs and normotensive Wistar rats.

RESULTS

Functional efficiency of CSCs from SHR was compromised relative to that in Wistar rat. Famotidine increased the migration and proliferation potential, along with retention of stemness of CSCs in treated SHRs. Cellular senescence and oxidative stress were also reduced. The expression of H2R was unaffected by the treatment.

DISCUSSION

As anticipated, CSCs from SHRs were functionally impaired. Stem cell attributes of famotidine-treated SHRs was comparable to that of Wistar rats. Therefore, in addition to being cardioprotective, the histamine 2 receptor antagonist modulated cardiac stem cells characteristics. Restoration of stem cell efficiency by famotidine is possibly mediated by reduction of oxidative stress as the expression of H2R was unaffected by the treatment. Maintenance of healthy stem cell population is suggested as a possible mechanism underlying the cardioprotective effect of famotidine.

On-slide detection of enzymatic activities in selected single cells

With increasing recognition of the importance in addressing cell-to-cell heterogeneity for the understanding of complex biological systems, there is a growing need for assays capable of single cell analyses. In the current study, we describe the measurement of human topoisomerase I activity in single CD44 positive Caco2 cells specifically captured from a mixed population on glass slides, which were dual functionalized with anti-CD44-antibodies and specific DNA primers. On-slide lysis of captured CD44 positive cells, resulted in the release of human topoisomerase I, allowing the enzyme to circularize a specific linear DNA substrate added to the slides. The generated circles hybridized to the anchored DNA primers and acted as templates for a solid support rolling circle amplification reaction leading to the generation of long tandem repeat products that were detected at the single molecule level in a fluorescent microscope upon hybridization of fluorescent labelled probes. The on-slide detection system was demonstrated to be directly quantitative and specific towards CD44 positive cells. Moreover, it allowed reproducible detection of human topoisomerase I activity in single cells.

Aptamer-Based Therapeutic Approaches to Target Cancer Stem Cells

Cancer stem cells (CSCs) are believed to be a principal cellular source for tumour progression and therapeutic drug resistance as they are capable of self-renewal and can differentiate into cancer cells. Importantly, CSCs acquire the ability to evade the killing effects of cytotoxic agents through changes at the genetic, epigenetic and micro-environment levels. Therefore, therapeutic strategies targeting CSCs hold great potential as an avenue for cancer treatment. Aptamers or "chemical antibodies" are a group of single-stranded nucleic acid (DNA or RNA) oligonucleotides with distinctive properties such as smaller size, lower toxicity and less immunogenicity compared to conventional antibodies. They have been frequently used to deliver therapeutic payloads to cancer cells and have achieved encouraging anti-tumour effects. This review discusses progress in CSC evolution theory and the role of aptamers to target CSCs for cancer treatment. Challenges of aptamer-mediated CSC targeting approaches are also discussed.

GE11 peptide-conjugated nanoliposomes to enhance the combinational therapeutic efficacy of docetaxel and siRNA in laryngeal cancers

In this study, dual therapeutic-loaded GE11 peptide-conjugated liposomes were developed and applied to enhance therapeutic efficacies of standard-of-care regimens for the treatment of laryngeal cancer. The therapeutic strategy used here was a combination treatment with the chemotherapeutic docetaxel (DTX) and siRNA against the ABCG2 gene that regulates multidrug resistance in many tumor types. Liposome-encapsulated DTX/ABCG2-siRNA molecules were targeted to recognize tumor cells of squamous morphology by conjugation to the EGFR-targeting ligand, GE11. Targeted, drug-infused liposomes were nanosized and exhibited controlled release of DTX. Presence of GE11 peptides on liposomal surfaces enhanced the quantities of liposomal constructs taken up by Hep-2 laryngeal cancer cells. GE11 peptide-conjugated liposomes also enhanced cytotoxic effects against Hep-2 laryngeal cancer cells when compared to treatment with free DTX, thereby reducing IC50 values. Additionally, GE11 peptide-conjugated liposomes had significantly increased anti-tumor and apoptotic effects. Treatments with the GDSL nanoparticle formulation inhibited tumor growth in Hep-2 xenograft-bearing nude mouse models when compared to treatments with non-targeted NP constructs. Treatment of the mouse models with GE11 peptide-conjugated liposomes mitigated toxicities observed after treatment with free DTX. Taken together, liposomal encapsulation of DTX and ABCG2-siRNA improved the anti-tumor effects of treatment with free DTX in Hep-2 cell lines, and conjugation of GE11 peptides to liposomal constructs enhanced anti-tumor efficacies and specificities in laryngeal cancer cells.

Effective treatment of drug resistant recurrent breast tumors harboring cancer stem-like cells by staurosporine/epirubicin co-loaded polymeric micelles

Breast cancer recurrence and resistance are associated with cancer stem-like cell (CSC) sub-populations. As conventional therapies fail to treat CSCs, institution of novel therapeutic strategies capable of eradicating both cancer cells and CSCs is central for achieving effective treatments with long-term survival. Here, we studied the ability of polymeric micelles cooperatively loading the cytotoxic drug epirubicin (Epi) and the CSC inhibitor staurosporine (STS) to treat breast tumors, particularly when tumors relapsed after chemotherapy. The STS/Epi-loaded micelles (STS/Epi/m) demonstrated potent therapeutic efficacy against both naïve orthotopic 4T1-luc breast tumors and their recurrent Epi-resistant counterparts, significantly prolonging survival. This efficacy enhancement of STS/Epi/m was correlated with the ability of the micelles to suppress the CSC-associated sub-populations of breast cancer, i.e. the aldehyde dehydrogenase-positive (ALDH⁺) population and the CD44⁺/CD24^- fraction, in Epi-resistant cells and tumors. These results demonstrated STS/Epi/m as a promising strategy for effective management of breast cancer.

Nanocarrier based approaches for targeting breast cancer stem cells

Breast cancer stem cells (BCSCs) are heterogeneous subpopulation of tumour initiating cells within breast tumours. They are spared even after chemotherapy and responsible for tumour relapse. Targeting BCSCs is, therefore, necessary to achieve radical cure in breast cancer. Despite the availability of agents targeting BCSCs, their clinical application is limited due to their off-target effects and bioavailability issues. Nanotechnology based drug carriers (nanocarriers) offer various advantages to deliver anti-BCSCs agents specifically to their target sites by overcoming their bioavailability issues. In this review, we describe various strategies for targeting BCSCs using nanocarriers.

MicroRNAs are important regulators of drug resistance in colorectal cancer

Despite of continuous development of cancer treatment over the past decades, drug resistance is still one of the major hurdles of effective therapy for advanced colorectal cancer (CRC) worldwide and the understanding of its underlying mechanisms remains limited. Data which have emerged suggests that many microRNAs (miRNAs) may contribute to drug resistance in CRC. Major findings on miRNA functions in drug resistance of CRC are systemically reviewed here, with the goal of providing new updates to broaden our comprehension of its mechanisms and evidence to utilize miRNAs as potential therapeutic targets for CRC treatment.

The Implications and Future Perspectives of Nanomedicine for Cancer Stem Cell Targeted Therapies

Cancer stem cells (CSCs) are believed to exhibit distinctive self-renewal, proliferation, and differentiation capabilities, and thus play a significant role in various aspects of cancer. CSCs have significant impacts on the progression of tumors, drug resistance, recurrence and metastasis in different types of malignancies. Due to their primary role, most researchers have focused on developing anti-CSC therapeutic strategies, and tremendous efforts have been put to explore methods for selective eradication of these therapeutically resistant CSCs. In recent years, many reports have shown the use of CSCs-specific approaches such as ATP-binding cassette (ABC) transporters, blockade of self-renewal and survival of CSCs, CSCs surface markers targeted drugs delivery and eradication of the tumor microenvironment. Also, various therapeutic agents such as small molecule drugs, nucleic acids, and antibodies are said to destroy CSCs selectively. Targeted drug delivery holds the key to the success of most of the anti-CSCs based drugs/therapies. The convention CSCs-specific therapeutic agents, suffer from various problems. For instance, limited water solubility, small circulation time and inconsistent stability of conventional therapeutic agents have significantly limited their efficacy. Recent advancement in the drug delivery technology has demonstrated that specially designed nanocarrier-based drug delivery approaches (nanomedicine) can be useful in delivering sufficient amount of drug molecules even in the most interiors of CSCs niches and thus can overcome the limitations associated with the conventional free drug delivery methods. The nanomedicine has also been promising in designing effective therapeutic regime against pump-mediated drug resistance (ATP-driven) and reduces detrimental effects on normal stem cells. Here we focus on the biological processes regulating CSCs' drug resistance and various strategies developed so far to deal with them. We also review the various nanomedicine approaches developed so far to overcome these CSCs related issues and their future perspectives.

Dual-Mode Imaging-Guided Synergistic Chemo- and Magnetohyperthermia Therapy in a Versatile Nanoplatform To Eliminate Cancer Stem Cells

Cancer stem cells (CSCs) have been identified as a new target for therapy in diverse cancers. Traditional therapies usually kill the bulk of cancer cells, but are often unable to effectively eliminate CSCs, which may lead to drug resistance and cancer relapse. Herein, we propose a novel strategy: fabricating multifunctional magnetic Fe₃O₄@PPr@HA hybrid nanoparticles and loading it with the Notch signaling pathway inhibitor N-[N-(3,5-difluorophenacetyl-l-alanyl)]-S-phenylglycinet-butylester (DAPT) to eliminate CSCs. Hyaluronic acid ligands greatly enhance the accumulation of the hybrid nanoparticles in the tumor site and in the CSCs. Both hyaluronase in the tumor microenvironment and the magnetic hyperthermia effect of the inner magnetic core can accelerate the release of DAPT. This controlled release of DAPT in the tumor site further enhances the ability of the combination of chemo- and magnetohyperthermia therapy to eliminate cancer stem cells. With the help of polypyrrole-mediated photoacoustic and Fe₃O₄-mediated magnetic resonance imaging, the drug release can be precisely monitored in vivo. This versatile nanoplatform enables effective elimination of the cancer stem cells and monitoring of the drugs.

Genomic markers of ovarian adenocarcinoma and its relevancy to the effectiveness of chemotherapy

Ovarian cancer is the eighth most common cancer and the seventh highest cause of cancer-associated mortality in women worldwide. It is the second highest cause of mortality among female reproductive malignancies. The current standard first-line treatment for advanced ovarian cancer includes a combination of surgical debulking and standard systemic platinum-based chemotherapy with carboplatin and paclitaxel. Although a deeper understanding of this disease has been attained, relapse occurs in 70% of patients 18 months subsequent to the first-line treatment. Therefore, it is crucial to develop a novel drug that effectively affects ovarian cancer, particularly tumors that are resistant to current chemotherapy. The aim of the present study was to identify genes whose expression may be used to predict survival time or prognosis in ovarian cancer patients treated with chemotherapy. Gene or protein expression is an important issue in chemoresistance and survival prediction in ovarian cancer. In the present study, the research group consisted of patients treated at the Surgical Clinic of the Gynecology and Obstetrics Gynecological Clinical Hospital, Poznan University of Medical Sciences (Poznan, Poland) between May 2006 and November 2014. Additional eligibility criteria were a similar severity (International Federation of Gynecolgy and Obstetrics stage III) at the time of diagnosis, treatment undertaken in accordance with the same schedule, and an extremely good response to treatment or a lack of response to treatment. The performance of the OncoScan^® assay was evaluated by running the assay on samples obtained from the four patients and by following the recommended protocol outlined in the OncoScan assay manual. The genomic screening using Affymetrix OncoScan Arrays resulted in the identification of large genomic rearrangements across all cancer tissues. In general, chromosome number changes were detected in all examined tissues. The OncoScan arrays enabled the identification of ~100 common somatic mutations. Chemotherapy response in ovarian cancer is extremely complex and challenging to study. The present study identified specific genetic alterations associated with ovarian cancer, but not with response for treatment.

The Dual Roles of MYC in Genomic Instability and Cancer Chemoresistance

Cancer is associated with genomic instability and aging. Genomic instability stimulates tumorigenesis, whereas deregulation of oncogenes accelerates DNA replication and increases genomic instability. It is therefore reasonable to assume a positive feedback loop between genomic instability and oncogenic stress. Consistent with this premise, overexpression of the MYC transcription factor increases the phosphorylation of serine 139 in histone H2AX (member X of the core histone H2A family), which forms so-called γH2AX, the most widely recognized surrogate biomarker of double-stranded DNA breaks (DSBs). Paradoxically, oncogenic MYC can also promote the resistance of cancer cells to chemotherapeutic DNA-damaging agents such as cisplatin, clearly implying an antagonistic role of MYC in genomic instability. In this review, we summarize the underlying mechanisms of the conflicting functions of MYC in genomic instability and discuss when and how the oncoprotein exerts the contradictory roles in induction of DSBs and protection of cancer-cell genomes.

Selective photocytotoxicity of anthrols on cancer stem-like cells: The effect of quinone methides or reactive oxygen species

Cancer stem cells (CSCs) are a subpopulation of cancer cells that share properties of embryonic stem cells like pluripotency and self-renewal and show increased resistance to chemo- and radiotherapy. Targeting CSC, rather than cancer cells in general, is a novel and promising strategy for cancer treatment. Novel therapeutic approaches, such as photodynamic therapy (PDT) have been investigated. A promising group of phototherapeutic agents are reactive intermediates - quinone methides (QMs). This study describes preparation of QM precursor, 2-hydroxy-3-hydroxymethylanthracene (2) and a detailed photochemical and photobiological investigation on similar anthracene derivatives 3 and 4. Upon photoexcitation with near visible light at λ > 400 nm 1 and 2 give QMs, that were detected by laser flash photolysis and their reactivity with nucleophiles has been demonstrated in the preparative irradiation experiments where the corresponding adducts were isolated and characterized. 3 and 4 cannot undergo photodehydration and deliver QM, but lead to the formation of phenoxyl radical and singlet oxygen, respectively. The activity of 1-4 was tested on a panel of human tumor cell lines, while special attention was devoted to demonstrate their potential selectivity towards the cells with CSC-like properties (HMLEshEcad). Upon the irradiation of cell lines treated with 1-4, an enhancement of antiproliferative activity was demonstrated, but the DNA was not the target molecule. Confocal microscopy revealed that these compounds entered the cell and, upon irradiation, reacted with cellular membranes. Our experiments demonstrated moderate selectivity of 2 and 4 towards CSC-like cells, while necrosis was shown to be a dominant cell death mechanism. Especially interesting was the selectivity of 4 that produced higher levels of ROS in CSC-like cells, which forms the basis for further research on cancer phototherapy, as well as for the elucidation of the underlying mechanism of the observed CSC selectivity based on oxidative stress activation.

Targeting Cancer Stem Cells-A Renewed Therapeutic Paradigm

Metastasis is often accompanied by radio- and chemotherapeutic resistance to anticancer treatments and is the major cause of death in cancer patients. Better understanding of how cancer cells circumvent therapeutic insults and how disseminated cancer clones generate life-threatening metastases would therefore be paramount to the development of effective therapeutic approaches for clinical management of malignant disease. Mounting reports over the past two decades have provided evidence for the existence of a minor population of highly malignant cells within liquid and solid tumors, which are capable of self-renewing and of regenerating secondary growths with the heterogeneity of the primary tumors from which they derive. These cells, called tumor-initiating cells or cancer stem cells (CSCs) exhibit increased resistance to standard radio- and chemotherapies and appear to have mechanisms that enable them to evade immune surveillance. CSCs are therefore considered to be responsible for systemic residual disease after cancer therapy, as well as for disease relapse. How CSCs develop, the nature of the interactions they establish with their microenvironment, their phenotypic and functional characteristics, as well as their molecular dependencies have all taken center stage in cancer therapy. Indeed, improved understanding of CSC biology is critical to the development of important CSC-based anti-neoplastic approaches that have the potential to radically improve cancer management. Here, we summarize some of the most pertinent elements regarding CSC development and properties, and highlight some of the clinical modalities in current development as anti-CSC therapeutics.

Metformin increases chemo-sensitivity via gene downregulation encoding DNA replication proteins in 5-Fu resistant colorectal cancer cells

Metformin is most widely prescribed for type 2 diabetes. Recently, evidences have shown that metformin has anticancer effects on pancreatic-, colorectal-, ovarian-, and other cancers. Because metformin has less adverse effects and is inexpensive, it could be a useful chemo-therapeutic agent with anticancer effects. In this study, we demonstrated metformin inhibited by cell proliferation, cell migration ability, clonogenic ability, and cancer stem cell population. Metformin also induced cell cycle arrest in parental-(SNU-C5), and 5-Fu resistant-colorectal cancer cell line (SNU-C5_5FuR). Moreover, a treatment that combines 5-Fu and metformin was found to have a synergistic effect on the cell proliferation rate, especially in SNU-C5_5FuR, which was mediated by the activation of AMPK pathway and NF-ƙB pathway, well-known metformin mechanisms. In this study, we suggested novel anticancer mechanism of metformin that inhibited DNA replication machinery, such as the MCM family in SNU-C5_5FuR. In conclusion, we provided that how metformin acts as not only a chemo-sensitizer, but also as a synergistic effector of 5-Fu in the 5-Fu resistant-cell line. We speculate that metformin used for adjuvant therapy is effective on 5-Fu resistant cancer cells.

UM-Chor1: establishment and characterization of the first validated clival chordoma cell line

OBJECTIVE Chordomas are rare malignant tumors thought to arise from remnants of the notochord. They can be located anywhere along the axial skeleton but are most commonly found in the clival and sacrococcygeal regions, where the notochord regresses during fetal development. Chordomas are resistant to many current therapies, leaving surgery as the primary method of treatment. Cancer cell lines have been useful for developing new cancer treatments in a laboratory setting that can then be transferred to the clinic, but there are only 4 validated chordoma cell lines available. The objective of this work was to establish chordoma cell lines from surgical tissue in order to expand the library of lines available for laboratory research. METHODS Chordoma tissue from the clivus was processed and sorted by flow cytometry to obtain an isolated population of chordoma cells. These cells were grown in culture and expanded until enough doublings to consider the line established. Identification of a chordoma cell line was made with known markers for chordoma, and the line was observed for ALDH (aldehyde dehydrogenase) subpopulations and tested in serum-free growth conditions as well as in vivo. RESULTS A fifth chordoma cell line, UM-Chor1, was successfully established. This is the first chordoma cell line originating from the clivus. Validation was confirmed by phenotype and positivity for the chordoma markers CD24 and brachyury. The authors also attempted to identify an ALDH^high cell population in UM-Chor1, UCH1, and UCH2 but did not detect a distinct population. UM-Chor1 cells were able to form spheroids in serum-free culture, were successfully transduced with luciferase, and could be injected parasacrally and grown in NOD/SCID mice. CONCLUSIONS The availability of this novel clival chordoma cell line for in vitro and in vivo research provides an opportunity for developments in treatment against the disease.

G9a governs colon cancer stem cell phenotype and chemoradioresistance through PP2A-RPA axis-mediated DNA damage response

BACKGROUND AND PURPOSE

Neoadjuvant concurrent chemoradiotherapy (CCRT) is a standard treatment of locally advanced colon cancer cell (CRC). In order to maximize efficacy and minimize toxicity, new drugs have been developed and used in combination with CCRT. Recently, it has been shown that G9a plays a role in mediating phenotypes of cancer stem cells (CSCs). This study aimed to characterize G9a as a biomarker in predicting therapy response to prevent overtreatment and adverse effects in CRC patients.

EXPERIMENTAL DESIGN

The primary tumors from 39 patients who received CCRT for rectal cancer were selected. In vivo tumor xenograft models for tumorigenic properties in immunodeficient mice were developed. In vitro stemness ability was performed by tumor-sphere assays, cell response to anti-cancer agents and stemness-related genes analysis.

RESULTS

Cells survived from radiation treatment, and displayed high levels of G9a. A significantly positive correlation was shown between G9a and CSCs marker CD133 in locally advanced rectal cancer patients with CCRT. Knockdown of G9a increased the sensitivity of cells to radiation treatment and sensitized cells to DNA damage agents through PP2A-RPA axis.

CONCLUSIONS

Our study theorized that G9a might serve as a novel target in colon cancer, which offers exciting potential in prediction of response to preoperative chemoradiotherapy in patients with advanced CRC.

Integrating the glioblastoma microenvironment into engineered experimental models

Glioblastoma (GBM) is the most lethal cancer originating in the brain. Its high mortality rate has been attributed to therapeutic resistance and rapid, diffuse invasion - both of which are strongly influenced by the unique microenvironment. Thus, there is a need to develop new models that mimic individual microenvironmental features and are able to provide clinically relevant data. Current understanding of the effects of the microenvironment on GBM progression, established experimental models of GBM and recent developments using bioengineered microenvironments as ex vivo experimental platforms that mimic the biochemical and physical properties of GBM tumors are discussed.

Synergistic Effects of Nanodrug, Ultrasound Hyperthermia, and Thermal Ablation on Solid Tumors-An Animal Study

OBJECTIVE

Delivery barriers of nanodrug in large tumors due to heterogeneous blood supply, elevated interstitial pressure, and long transport distances can degrade the efficacy of cancer treatment. In this study, we proposed a therapeutic strategy to improve the tumor growth inhibition by injecting pegylated liposomal doxorubicin (PLD), and then applying a short time of ultrasound hyperthermia (HT) on the entire solid tumor, and inflicting ultrasound thermal ablation (Ab) in the low-perfused tumor region.

METHODS

BALB/c female mice with an average weight of 20 g were adopted and murine breast cancer cells 4T1 were subcutaneously implanted into the flank. A 1.0-MHz planar and a 0.47-MHz focused ultrasound transducers were used, respectively, for the HT and Ab treatment.

RESULTS

For a PLD dose of 5 mg/kg, the PLD + HT(42 °C, 10 min) group caused a significant decrease in the tumor size as compared with the control and the PLD group, but there were no significant differences between the PLD + HT group and the PLD + Ab(56 °C, 49 s) + HT group. For a PLD dose of 3 mg/kg, the tumor sizes among the four groups were mutually significant. The level of reduction in tumor was PLD + Ab + HT > PLD + HT > PLD > control.

CONCLUSION

The combination of anticancer nanodrug and ultrasound thermal treatment could remarkably suppress cancer tumor growth with a minimum compromise of side effects.

SIGNIFICANCE

The strategy of using thermal Ab in locations that are not reached by nanodrug with mild HT shows a promising potential for the entire tumor treatment.

Lectin, Galactoside-Binding Soluble 3 Binding Protein Promotes 17-N-Allylamino-17-demethoxygeldanamycin Resistance through PI3K/Akt Pathway in Lung Cancer Cell Line

Heat shock protein 90 (HSP90) stabilizing oncoproteins has been an attractive target in cancer therapy. 17-N-Allylamino-17-demethoxygeldanamycin (17-AAG), an HSP90 inhibitor, was tested in phase II/III clinical trials, but due to lack of efficacy, clinical evaluation of 17-AAG has achieved limited success, which led to resistance to 17-AAG. However, the mechanism of 17-AAG resistance has not clearly been identified. Here, we identified LGALS3BP (Lectin, galactoside-binding soluble 3 binding protein), a secretory glycoprotein, as a 17-AAG resistance factor. In the clinical reports, it was suggested that LGALS3BP was associated with low survival rate, development of cancer progression, and enhancement of metastasis in human cancers. As we confirmed that the LGALS3BP level was increased in 17-AAG-resistant cells (H1299_17R) compared with that of the parental cell line (H1299_17P), knockdown of LGALS3BP expression increased sensitivity to 17-AAG in H1299_17R cells. Overexpression of LGALS3BP also augmented PI3K/Akt and ERK signaling pathways. Furthermore, we determined that the PI3K/Akt signaling pathway was involved in LGALS3BP-mediated 17-AAG resistance in vitro and in vivo, demonstrating that LGALS3BP mediates the resistance against 17-AAG through PI3K/Akt activation rather than ERK activation. These findings suggest that LGALS3BP would be a target to overcome resistance to 17-AAG in lung cancer. For example, the combination of 17-AAG and PI3K/Akt inhibitor would effectively suppress acquired resistance to 17-AAG. In conclusion, targeting of LGALS3BP-mediated-specific survival signaling pathway in resistant cells may provide a novel therapeutic model for the cancer therapy. Mol Cancer Ther; 16(7); 1355-65. ©2017 AACR.

Effects of U0126 and MK2206 on cell growth and re-growth of endometriotic stromal cells grown on substrates of varying stiffness

Endometriosis is a common gynecological disorder responsible for infertility and pelvic pain. A complete cure for patients with endometriosis awaits new targets and strategies. Here we show that U0126 (a MEK inhibitor) and MK2206 (an AKT inhibitor) synergistically inhibit cell growth of deep endometriotic stromal cells (DES) grown on polyacrylamide gel substrates (PGS) of varying stiffness (2 or 30 kilopascal [kPa]) or plastic in vitro. No significant differences in cell proliferation were observed among DES, endometrial stromal cells of patients with endometriosis (EES) from the proliferative phase (P), EES-S (secretory phase) and EES-M (menstrual phase) compared to cells grown on a substrate of the same stiffness at both higher (U0126 [30 μM] and MK2206 [9 μM]) and lower (U0126 [15 μM] and MK2206 [4.5 μM]) combined doses. However, cell re-growth of DES after drug discontinuation was higher than that of EES-P and EES-S when cells were grown on rigid substrates at both combined doses. Combination U0126 and MK2206 treatment is more effective than each drug alone in cell growth inhibition of DES. However, further studies are required to investigate the mechanisms underlying high cell survival and proliferation after drug discontinuation for developing target therapies that prevent recurrence.

Drug-Loaded Polymeric Nanoparticles for Cancer Stem Cell Targeting

Cancer stem cells (CSCs) have been reported to play critical roles in tumor initiation, propagation, and regeneration of cancer. Nano-size vehicles are employed to deliver drugs to target the CSCs for cancer therapy. Polymeric nanoparticles have been considered as the most efficient vehicles for drug delivery due to their excellent pharmacokinetic properties. The CSCs specific antibodies or ligands can be conjugated onto the surface or interior of nanoparticles to successfully target and finally eliminate CSCs. In this review, we focus on the approaches of polymeric nanoparticles design for loading drug, and their potential application for CSCs targeting in cancer therapy.

n-Butylidenephthalide Regulated Tumor Stem Cell Genes EZH2/AXL and Reduced Its Migration and Invasion in Glioblastoma

Glioblastoma (GBM) is one of the most common and aggressive types of brain tumor. Due to its highly recurrent rate and poor prognosis, the overall survival time with this type of tumor is only 20–21 months. Recent knowledge suggests that its recurrence is in part due to the presence of cancer stem cells (CSCs), which display radioresistant, chemoresistant, self-renewal and tumorigenic potential. Enhancers of Zeste 2 (EZH2) and AXL receptor tyrosine kinase (AXL) are both highly expressed in GBM. Additionally, they are an essential regulator involved in CSCs maintenance, migration, invasion, epithelial-to-mesenchymal transition (EMT), stemness, metastasis and patient survival. In this study, we used a small molecule, n-butylidenephthalide (BP), to assess the anti-GBM stem-like cells potential, and then tried to find out the associated genes involved with regulation in migration and invasion. We demonstrated that BP reduced the expression of AXL and stemness related genes in a dose-dependent manner. The migratory and invasive capabilities of GBM stem-like cells could be reduced by AXL/EZH2. Finally, in the overexpression of AXL, EZH2 and Sox2 by transfection in GBM stem-like cells, we found that AXL/EZH2/TGF-β1, but not Sox2, might be a key regulator in tumor invasion, migration and EMT. These results might help in the development of a new anticancer compound and can be a target for treating GBM.

Targeting therapy-resistant cancer stem cells by hyperthermia

Eradication of all malignant cells is the ultimate but challenging goal of anti-cancer treatment; most traditional clinically-available approaches fail because there are cells in a tumour that either escape therapy or become therapy-resistant. A subpopulation of cancer cells, the cancer stem cells (CSCs), is considered to be of particular significance for tumour initiation, progression and metastasis. CSCs are considered in particular to be therapy-resistant and may drive disease recurrence, which positions CSCs in the focus of anti-cancer research, but successful CSC-targeting therapies are limited. Here, we argue that hyperthermia - a therapeutic approach based on local heating of a tumour - is potentially beneficial for targeting CSCs in solid tumours. First, hyperthermia has been described to target cells in hypoxic and nutrient-deprived tumour areas where CSCs reside and ionising radiation and chemotherapy are least effective. Second, hyperthermia can modify factors that are essential for tumour survival and growth, such as the microenvironment, immune responses, vascularisation and oxygen supply. Third, hyperthermia targets multiple DNA repair pathways, which are generally upregulated in CSCs and protect them from DNA-damaging agents. Addition of hyperthermia to the therapeutic armamentarium of oncologists may thus be a promising strategy to eliminate therapy-escaping and -resistant CSCs.

Anti-Cancer Phytometabolites Targeting Cancer Stem Cells

Medicinal plants are a plentiful source of bioactive molecules with much structural diversity. In cancer treatment, molecules obtained from plants represent an attractive alternative to other treatments because several plant-derived compounds have exhibited lower toxicity and higher selectivity against cancer cells. In this review, we focus on the possible application of bioactive molecules obtained from plants against more primitive cell populations in cancers, cancer stem cells. Cancer stem cells are present in several kinds of tumors and are responsible for recurrences and metastases. Common anti-cancer drugs exhibit lower effectiveness against cancer stem cells because of their biological features. However, recently discovered natural phytometabolites exert cytotoxic effects on this rare population of cells in cancers. Therefore, this review presents the latest research on promising compounds from plants that can act as antitumor drugs and that mainly affect stem cell populations in cancers.

Liposomal Nanoparticles Carrying anti-IL6R Antibody to the Tumour Microenvironment Inhibit Metastasis in Two Molecular Subtypes of Breast Cancer Mouse Models

Tumour microenvironment (TME) contributes significantly towards potentiating the stemness and metastasis properties of cancer cells. IL6-Stat3 is one of the important cell signaling pathways in mediating the communication between tumour and immune cells. Here, we have systematically developed a novel anti-CD44 antibody-mediated liposomal nanoparticle delivery system loaded with anti-IL6R antibody, which could specifically target the TME of CD44⁺ breast cancer cells in different mouse models for triple negative and luminal breast cancer. This nanoparticle had an enhanced and specific tumour targeting efficacy with dramatic anti-tumour metastasis effects in syngeneic BALB/c mice bearing 4T1 cells as was in the syngeneic MMTV-PyMT mice. It inhibited IL6R-Stat3 signaling and moderated the TME, characterized by the reduced expression of genes encoding Stat3, Sox2, VEGFA, MMP-9 and CD206 in the breast tissues. Furthermore, this nanoparticle reduced the subgroups of Sox2⁺ and CD206⁺ cells in the lung metastatic foci, demonstrating its inhibitory effect on the lung metastatic niche for breast cancer stem cells. Taken together, the CD44 targeted liposomal nanoparticles encapsulating anti-IL6R antibody achieved a significant effect to inhibit the metastasis of breast cancer in different molecular subtypes of breast cancer mouse models. Our results shed light on the application of nanoparticle mediated cancer immune-therapy through targeting TME.

Raman endoscopy for monitoring the anticancer drug treatment of colorectal tumors in live mice

A miniaturized Raman endoscope (mRE) system was employed to study the effects of anticancer treatment on colorectal tumors in a live murine model.

Cancer Metabolism: Fueling More than Just Growth

The early landmark discoveries in cancer metabolism research have uncovered metabolic processes that support rapid proliferation, such as aerobic glycolysis (Warburg effect), glutaminolysis, and increased nucleotide biosynthesis. However, there are limitations to the effectiveness of specifically targeting the metabolic processes which support rapid proliferation. First, as other normal proliferative tissues also share similar metabolic features, they may also be affected by such treatments. Secondly, targeting proliferative metabolism may only target the highly proliferating "bulk tumor" cells and not the slower-growing, clinically relevant cancer stem cell subpopulations which may be required for an effective cure. An emerging body of research indicates that altered metabolism plays key roles in supporting proliferation-independent functions of cancer such as cell survival within the ischemic and acidic tumor microenvironment, immune system evasion, and maintenance of the cancer stem cell state. As these aspects of cancer cell metabolism are critical for tumor maintenance yet are less likely to be relevant in normal cells, they represent attractive targets for cancer therapy.

Development and characterisation of disulfiram-loaded PLGA nanoparticles for the treatment of non-small cell lung cancer

Non-Small Cell Lung Cancer (NSCLC) is the most common type of lung cancer in both men and women. A recent phase IIb study demonstrated that disulfiram (DSF) in combination with cisplatin and vinorelbine was well tolerated and prolonged the survival of patients with newly diagnosed NSCLC. However, DSF is rapidly (4min) metabolised in the bloodstream and it is this issue which is limiting its anticancer application in the clinic. We have recently demonstrated that a low dose of DSF-loaded poly(lactic-co-glycolic acid) (PLGA) nanoparticles supplemented with oral Cu inhibited tumour growth and reduced metastasis in a xenograft mouse lung cancer model. Here we demonstrate the influence of PLGA polymer, stabilizer loading and molecular weight as well as sonication time on the characteristics, including DSF release and the cytotoxicity of 10% w/w DSF-loaded PLGA nanoparticles. The paper demonstrates that the choice of PLGA as no significance on the characteristics of the nanoparticles apart from their DSF release, which is due to the differing degradation rates of the polymers. However, increasing the loading and molecular weight of the stabilizer as well as the sonication time reduced the size of the nanoparticles, reduced their ability to protect the DSF from reacting with Cu and degrading in serum, while increasing their DSF release rate and cytotoxicity. Additionally, increasing the sonication time resulted in the premature degradation of the PLGA, which increased the permeability of the nanoparticles further decreasing their ability to protect DSF from reacting with Cu and degrading in serum, while increasing their DSF release rate and cytotoxicity.

Nanomedicine strategies for sustained, controlled and targeted treatment of cancer stem cells

Cancer stem cells (CSCs) are original cancer cells that are of characteristics associated with normal stem cells. CSCs are toughest against various treatments and thus responsible for cancer metastasis and recurrence. Therefore, development of specific and effective treatment of CSCs plays a key role in improving survival and life quality of cancer patients, especially those in the metastatic stage. Nanomedicine strategies, which include prodrugs, micelles, liposomes and nanoparticles of biodegradable polymers, could substantially improve the therapeutic index of conventional therapeutics due to its manner of sustained, controlled and targeted delivery of high transportation efficiency across the cell membrane and low elimination by intracellular autophagy, and thus provide a practical solution to solve the problem encountered in CSCs treatment. This review gives briefly the latest information to summarize the concept, strategies, mechanisms and current status as well as future promises of nanomedicine strategies for treatment of CSCs.

Engineered Breast Cancer Cell Spheroids Reproduce Biologic Properties of Solid Tumors

Solid tumors develop as 3D tissue constructs. As tumors grow larger, spatial gradients of nutrients and oxygen and inadequate diffusive supply to cells distant from vasculature develops. Hypoxia initiates signaling and transcriptional alterations to promote survival of cancer cells and generation of cancer stem cells (CSCs) that have self-renewal and tumor-initiation capabilities. Both hypoxia and CSCs are associated with resistance to therapies and tumor relapse. This study demonstrates that 3D cancer cell models, known as tumor spheroids, generated with a polymeric aqueous two-phase system (ATPS) technology capture these important biological processes. Similar to solid tumors, spheroids of triple negative breast cancer cells deposit major extracellular matrix proteins. The molecular analysis establishes presence of hypoxic cells in the core region and expression of CSC gene and protein markers including CD24, CD133, and Nanog. Importantly, these spheroids resist treatment with chemotherapy drugs. A combination treatment approach using a hypoxia-activated prodrug, TH-302, and a chemotherapy drug, doxorubicin, successfully targets drug resistant spheroids. This study demonstrates that ATPS spheroids recapitulate important biological and functional properties of solid tumors and provide a unique model for studies in cancer research.

Doxycycline inhibits the cancer stem cell phenotype and epithelial-to-mesenchymal transition in breast cancer

Experimental evidence suggest that breast tumors originate from breast cancer stem cells (BCSCs), and that mitochondrial biogenesis is essential for the anchorage-independent clonal expansion and survival of CSCs, thus rendering mitochondria a significant target for novel treatment approaches. One of the recognized side effects of the FDA-approved drug, doxycycline is the inhibition of mitochondrial biogenesis. Here we investigate the mechanism by which doxycycline exerts its inhibitory effects on the properties of breast cancer cells and BCSCs, such as mammosphere forming efficiency, invasion, migration, apoptosis, the expression of stem cell markers and epithelial-to-mesenchymal transition (EMT) related markers of breast cancer cells. In addition, we explored whether autophagy plays a role in the inhibitory effect of doxycycline on breast cancer cells. We find that doxycyline can inhibit the viability and proliferation of breast cancer cells and BCSCs, decrease mammosphere forming efficiency, migration and invasion, and EMT of breast cancer cells. Expression of stem cell factors Oct4, Sox2, Nanog and CD44 were also significantly downregulated after doxycycline treatment. Moreover, doxycycline could down-regulate the expression of the autophagy marker LC-3BI and LC-3BII, suggesting that inhibiting autophagy may be responsible in part for the observed effects on proliferation, EMT and stem cell markers. The potent inhibition of EMT and cancer stem-like characteristics in breast cancer cells by doxycycline treatment suggests that this drug can be repurposed as an anti-cancer drug in the treatment of breast cancer patients in the clinic.

Nanomedicine-Mediated Therapies to Target Breast Cancer Stem Cells

Accumulating evidences have suggested the existence of breast cancer stem cells (BCSCs), which possess the potential of both self-renewal and differentiation. The origin of BCSCs might have relationship to the development of normal mammary stem cells. BCSCs are believed to play a key role in the initiation, recurrence and chemo-/radiotherapy resistances of breast cancer. Therefore, elimination of BCSCs is crucial for breast cancer therapy. However, conventional chemo and radiation therapies cannot eradicate BCSCs effectively. Fortunately, nanotechnology holds great potential for specific and efficient anti-BCSCs treatment. “Smart” nanocarriers can distinguish BCSCs from the other breast cancer cells and selectively deliver therapeutic agents to the BCSCs. Emerging findings suggest that BCSCs in breast cancer could be successfully inhibited and even eradicated by functionalized nanomedicines. In this review, we focus on origin of BCSCs, strategies used to target BCSCs, and summarize the nanotechnology-based delivery systems that have been applied for eliminating BCSCs in breast cancer.

The flavonoid apigenin reduces prostate cancer CD44(+) stem cell survival and migration through PI3K/Akt/NF-κB signaling

AIMS

Cancer stem cells (CSCs) are involved in drug resistance, metastasis and recurrence of cancers. The efficacy of apigenin on cell survival, apoptosis, migration and stemness properties were analyzed in CSCs.

MAIN METHODS

Prostate CSCs (CD44(+)) were isolated from human prostate cancer (PCa) PC3 cells using a magnetic-activated cell sorting system. PC3 and CSCs were treated with various concentrations of apigenin, docetaxel and their combinations for 48h.

KEY FINDINGS

Apigenin dose dependently inhibited CSCs and PC3 cell survival, and this was accompanied with a significant increase of p21 and p27. Apigenin induced apoptosis via an extrinsic caspase-dependent pathway by upregulating the mRNA expressions of caspases-8, -3 and TNF-α, but failed to regulate the intrinsic pathway as determined by the Bax, cytochrome c (Cyt-c) and APAF-1 in CSCs. In contrary to CSCs, apigenin induced intrinsic apoptosis pathway as evidenced by the induction of Bax, Cyt-c and caspase-3 while caspase-8, TNF-α and Bcl-2 levels remained unchanged in PC3 cells. The flavonoid strongly suppressed the migration rate of CSCs compared to untreated cells. Significant downregulation of matrix metallopeptidases-2, -9, Snail and Slug exhibits the ability of apigenin treatment to suppress invasion. The expressions of NF-κB p105/p50, PI3K, Akt and the phosphorylation of pAkt were decreased after apigenin treatment. Moreover, apigenin treatment significantly reduced pluripotency marker Oct3/4 protein expression which might be associated with the down-regulation of PI3K/Akt/NF-κB signaling.

SIGNIFICANCE

Our data indicated that, apigenin could be a useful compound to prevent proliferation and migration of cancer cells as well as CSCs.

Ultra-small lipid-polymer hybrid nanoparticles for tumor-penetrating drug delivery

Lipid-polymer hybrid nanoparticles, consisting of a polymeric core coated by a layer of lipids, are a class of highly scalable, biodegradable nanocarriers that have shown great promise in drug delivery applications. Here, we demonstrate the facile synthesis of ultra-small, sub-25 nm lipid-polymer hybrid nanoparticles using an adapted nanoprecipitation approach and explore their utility for targeted delivery of a model chemotherapeutic. The fabrication process is first optimized to produce a monodisperse population of particles that are stable under physiological conditions. It is shown that these ultra-small hybrid nanoparticles can be functionalized with a targeting ligand on the surface and loaded with drug inside the polymeric matrix. Further, the in vivo fate of the nanoparticles after intravenous injection is characterized by examining the blood circulation and biodistribution. In a final proof-of-concept study, targeted ultra-small hybrid nanoparticles loaded with the cancer drug docetaxel are used to treat a mouse tumor model and demonstrate improved efficacy compared to a clinically available formulation of the drug. The ability to synthesize a significantly smaller version of the established lipid-polymer hybrid platform can ultimately enhance its applicability across a wider range of applications.

CD164 promotes lung tumor-initiating cells with stem cell activity and determines tumor growth and drug resistance via Akt/mTOR signaling

CD164 is a cell adhesion molecule that increases hematopoietic stem cell proliferation, adhesion, and migration via C-X-C chemokine receptor type 4 (CXCR4) signaling. Emerging evidence indicates that elevated CD164 expression is associated with aggressive metastasis, advanced stages, and shorter overall survival in lung cancer. However, no data are available regarding the clinical significance of CD164 expression in lung cancer. This study explores whether CD164 promotes tumor-initiation and drug resistance through the stem cell property. Using tissue microarrays, we determine that CD164 expression is correlated with clinicopathological characteristics in human lung cancer. The CD164 overexpression in normal lung epithelial cells (BEAS2B cells) leads to malignant transformation in vitro, tumorigenicity in xenografted mice, stem cell-like property, and drug resistance through ATP-binding cassette transporters. The CD164 overexpression increases CXCR4 expression and activates Akt/mTOR signaling. Rapamycin, an mTOR inhibitor, hinders cell proliferation along with sphere formation in vitro and impedes tumor growth in vivo. In conclusion, we have provided evidence that CD164 promotes the growth of lung tumor-initiating cells with stem cell properties and induces tumor growth and drug resistance through Akt/mTOR signaling. Therefore, identification of CD164 as a cancer stem cell therapeutic marker may develop an effective therapy in patients with chemoresistant lung cancer.

A network based approach to drug repositioning identifies plausible candidates for breast cancer and prostate cancer

BACKGROUND

The high cost and the long time required to bring drugs into commerce is driving efforts to repurpose FDA approved drugs-to find new uses for which they weren't intended, and to thereby reduce the overall cost of commercialization, and shorten the lag between drug discovery and availability. We report on the development, testing and application of a promising new approach to repositioning.

METHODS

Our approach is based on mining a human functional linkage network for inversely correlated modules of drug and disease gene targets. The method takes account of multiple information sources, including gene mutation, gene expression, and functional connectivity and proximity of within module genes.

RESULTS

The method was used to identify candidates for treating breast and prostate cancer. We found that (i) the recall rate for FDA approved drugs for breast (prostate) cancer is 20/20 (10/11), while the rates for drugs in clinical trials were 131/154 and 82/106; (ii) the ROC/AUC performance substantially exceeds that of comparable methods; (iii) preliminary in vitro studies indicate that 5/5 candidates have therapeutic indices superior to that of Doxorubicin in MCF7 and SUM149 cancer cell lines. We briefly discuss the biological plausibility of the candidates at a molecular level in the context of the biological processes that they mediate.

CONCLUSIONS

Our method appears to offer promise for the identification of multi-targeted drug candidates that can correct aberrant cellular functions. In particular the computational performance exceeded that of other CMap-based methods, and in vitro experiments indicate that 5/5 candidates have therapeutic indices superior to that of Doxorubicin in MCF7 and SUM149 cancer cell lines. The approach has the potential to provide a more efficient drug discovery pipeline.

Infection-resistant MRI-visible scaffolds for tissue engineering applications

Tissue engineering utilizes porous scaffolds as template to guide the new tissue growth. Clinical application of scaffolding biomaterials is hindered by implant-associated infection and impaired in vivo visibility of construct in biomedical imaging modalities. We recently demonstrated the use of a bioengineered type I collagen patch to repair damaged myocardium. By incorporating superparamagnetic iron oxide nanoparticles into this patch, here, we developed an MRI-visible scaffold. Moreover, the embedded nanoparticles impeded the growth of Salmonella bacteria in the patch. Conferring anti-infection and MRI-visible activities to the engineered scaffolds can improve their clinical outcomes and reduce the morbidity/mortality of biomaterial-based regenerative therapies.

Cancer of the Pancreas: Molecular Pathways and Current Advancement in Treatment

Pancreatic cancer is one of the most lethal cancers among all malignances, with a median overall survival of <1 year and a 5-year survival of ~5%. The dismal survival rate and prognosis are likely due to lack of early diagnosis, fulminant disease course, high metastasis rate, and disappointing treatment outcome. Pancreatic cancers harbor a variety of genetic alternations that render it difficult to treat even with targeted therapy. Recent studies revealed that pancreatic cancers are highly enriched with a cancer stem cell (CSC) population, which is resistant to chemotherapeutic drugs, and therefore escapes chemotherapy and promotes tumor recurrence. Cancer cell epithelial to mesenchymal transition (EMT) is highly associated with metastasis, generation of CSCs, and treatment resistance in pancreatic cancer. Reviewed here are the molecular biology of pancreatic cancer, the major signaling pathways regulating pancreatic cancer EMT and CSCs, and the advancement in current clinical and experimental treatments for pancreatic cancer.

Microfluidics 3D gel-island chip for single cell isolation and lineage-dependent drug responses study

3D cell culture in the extracellular matrix (ECM), which not only provides structural support to cellular constituents, but also initiates regulatory biochemical cues for a variety of important cell functions in tissue, has become more and more important in understanding cancer pathology and drug testing. Although the ECM-gel has been used in cell culture both in bulk and on-chip, previous studies focused on collective cell behavior rather than single-cell heterogeneity. To track the behavior of each individual cell, we have developed a gel-island chip, which can form thousands of islands containing single cells encapsulated by the desired ECM. Optimized by Poisson's distribution, the device can attain 34% single cell capture efficiency of the exact number of single cells per island. A good culture media exchange rate and high cell viability can be achieved in the gel-islands. The cells in the islands can be automatically counted for high-throughput analysis. As a proof of concept, we monitored the proliferation and differentiation of single Notch+ (stem-like) T47D breast cancer cells. The 3D collagen gel environment was found to be favorable for the stem-like phenotype through better self-renewal and de-differentiation (Notch- to Notch+ transition). More interestingly, we found that the Notch- de-differentiated cells were more resistant to doxorubicin and cisplatin than the Notch+ cells. Combining the 3D ECM culture and single cell resolution, the presented platform can automatically analyze the individual cell behaviors of hundreds of cells using a small amount of drug and reagents.