The Role of MicroRNAs in Resistance to Current Pancreatic Cancer Treatment: Translational Studies and Basic Protocols for Extraction and PCR Analysis

Targeting miRNA and using miRNA as potential therapeutic options to bypass resistance in pancreatic ductal adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) is a highly aggressive disease with poor prognosis due to early metastasis, low diagnostic rates at early stages, and resistance to current therapeutic regimens. Despite numerous studies and clinical trials, the mortality rate for PDAC has shown limited improvement. Therefore, there is a pressing need to attain. a more comprehensive molecular characterization to identify biomarkers enabling early detection and evaluation of treatment response. MicroRNA (miRNAs) are critical regulators of gene expression on the post-transcriptional level, and seem particularly interesting as biomarkers due to their relative stability, and the ability to detect them in fixed tissue specimens and biofluids. Deregulation of miRNAs is common and affects several hallmarks of cancer and contribute to the oncogenesis and metastasis of PDAC. Unique combinations of upregulated oncogenic miRNAs (oncomiRs) and downregulated tumor suppressor miRNAs (TsmiRs), promote metastasis, characterize the tumor and interfere with chemosensitivity of PDAC cells. Here, we review several oncomiRs and TsmiRs involved in chemoresistance to gemcitabine and FOLFIRINOX in PDAC and highlighted successful/effective miRNA-based therapy approaches in vivo. Integrating miRNAs in PDAC treatment represents a promising therapeutic avenue that can be used as guidance for personalized medicine for PDAC patients.

Tumor microenvironment-responsive Ag2S-PAsp(DOX)-cRGD nanoparticles-mediated photochemotherapy enhances the immune response to tumor therapy

Chemotherapy drugs play important roles in clinical treatment, and most first-line regimens of cancer therapy contain chemotherapy drugs. In particular, some chemotherapeutic drugs can also produce ICD effect and enhance the immune response of the body. However, most chemotherapy drugs do not specifically target tumors or the complex tumor microenvironment, which renders their curative effect insufficient. Therefore, we constructed a tumor microenvironment-responsive drug delivery system (Ag₂S-PAsp-cRGD) combined with doxorubicin (DOX) for tumor therapy. Firstly, Ag₂S nanoparticles (NPs) were modified with polymer aspartic acid (PAsp) to construct the drug-loading platform. Then, an active targeting ligand (cRGD) was coupled through an amide reaction to enhance the functional targeting ability of the drug delivery system. In vivo imaging of the system showed that the nanoparticles accumulated in the tumor site, which facilitated the delivery of the chemotherapy drug DOX to the targeted tumor site. Furthermore, the photothermal effect of Ag₂S NPs can effectively killed tumor cells, and also helped the release of DOX from nanoparticles into tumor tissue, thus enhancing the chemotherapeutic effect. Moreover, combined with the ICD effect jointly induced by photothermal therapy (PTT) and DOX, the treatment further activated the host immune response against tumors by enhancing the presentation of antigens and promoting the differentiation of T cells. This strategy of photo-chemo-immunotherapy showed excellent antitumor effect, not only eliminating the primary tumor but also preventing recurrence and inhibiting metastasis.

Challenges and Opportunities for Clustered Regularly Interspaced Short Palindromic Repeats Based Molecular Biosensing

Clustered regularly interspaced short palindromic repeats, CRISPR, has recently emerged as a powerful molecular biosensing tool for nucleic acids and other biomarkers due to its unique properties such as collateral cleavage nature, room temperature reaction conditions, and high target-recognition specificity. Numerous platforms have been developed to leverage the CRISPR assay for ultrasensitive biosensing applications. However, to be considered as a new gold standard, several key challenges for CRISPR molecular biosensing must be addressed. In this paper, we briefly review the history of biosensors, followed by the current status of nucleic acid-based detection methods. We then discuss the current challenges pertaining to CRISPR-based nucleic acid detection, followed by the recent breakthroughs addressing these challenges. We focus upon future advancements required to enable rapid, simple, sensitive, specific, multiplexed, amplification-free, and shelf-stable CRISPR-based molecular biosensors.

Imidazo[2,1-b] [1,3,4]thiadiazoles with antiproliferative activity against primary and gemcitabine-resistant pancreatic cancer cells

A new series of eighteen imidazo [2,1-b] [1,3,4]thiadiazole derivatives was efficiently synthesized and screened for antiproliferative activity against the National Cancer Institute (NCI-60) cell lines panel. Two out of eighteen derivatives, compounds 12a and 12h, showed remarkably cytotoxic activity with the half maximal inhibitory concentration values (IC₅₀) ranging from 0.23 to 11.4 μM, and 0.29-12.2 μM, respectively. However, two additional compounds, 12b and 13g, displayed remarkable in vitro antiproliferative activity against pancreatic ductal adenocarcinoma (PDAC) cell lines, including immortalized (SUIT-2, Capan-1, Panc-1), primary (PDAC-3) and gemcitabine-resistant (Panc-1R), eliciting IC₅₀ values ranging from micromolar to sub-micromolar level, associated with significant reduction of cell-migration and spheroid shrinkage. These remarkable results might be explained by modulation of key regulators of epithelial-to-mesenchymal transition (EMT), including E-cadherin and vimentin, and inhibition of metalloproteinase-2/-9. High-throughput arrays revealed a significant inhibition of the phosphorylation of 45 tyrosine kinases substrates, whose visualization on Cytoscape highlighted PTK2/FAK as an important hub. Inhibition of phosphorylation of PTK2/FAK was validated as one of the possible mechanisms of action, using a specific ELISA. In conclusion, novel imidazothiadiazoles show potent antiproliferative activity, mediated by modulation of EMT and PTK2/FAK.

miRNA and Gene Expression in Pancreatic Ductal Adenocarcinoma

Pancreatic ductal adenocarcinoma (PDAC) remains a challenging disease that is mostly diagnosed late in the course of the illness. Unlike other cancers in which measurable successes have been achieved with traditional chemotherapy, targeted therapy, and, recently, immunotherapy, PDAC has proved to be poorly responsive to these treatments, with only marginal to modest incremental benefits using conventional cytotoxic therapy. There is, therefore, a great unmet need to develop better therapies based on improved understanding of biology and identification of predictive and prognostic biomarkers that would guide therapy. miRNAs are small noncoding RNAs that regulate the expression of some key genes by targeting their 3'-untranslated mRNA region. Aberrant expression of miRNAs has been linked to the development of various malignancies, including PDAC. A series of miRNAs have been identified as potential tools for early diagnosis, prediction of treatment response, and prognosis of patients with PDAC. In this review, we present a summary of the miRNAs that have been studied in PDAC in the context of disease biology.

Hyaluronic acid-modified cationic nanoparticles overcome enzyme CYP1B1-mediated breast cancer multidrug resistance

Aim: Enzyme CYP1B1 (CYP1B1) is usually overexpressed in multidrug resistance (MDR) breast cancer cells, which could metabolically inactivate docetaxel (DTX). Materials & methods: The cationic core–shell nanoparticles (hyaluronic acid/polyethyleneimine nanoparticles [HA/PEI NPs]) modified with hyaluronic acid (HA) were developed and coloaded with DTX and α-napthtoflavone (ANF, a CYP1B1 inhibitor) to overcome MDR in breast cancer induced by CYP1B1. Physicochemical characterization, MDR reversing effect in vitro and pharmacokinetics in vivo of HA/PEI NPs were evaluated. Results: The HA/PEI NPs exhibited spherical morphology with size of (193.6 ± 3.1) nm. The HA/PEI NPs could reverse MDR effectively by downregulating the expression of CYP1B1. The HA/PEI NPs improved the bioavailability of DTX. Conclusion: The HA/PEI NPs might be a promising strategy to overcome CYP1B1-mediated breast cancer MDR.

Internal enhancement of DNA damage by a novel bispecific antibody-drug conjugate-like therapeutics via blockage of mTOR and PD-L1 signal pathways in pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is a refractory malignant tumor with poor prognosis, limited chemotherapeutic efficacy, and only about 5% of 5-year survival rate. We generated a dual-targeting ligand-based lidamycin (DTLL) to investigate its efficacy against pancreatic cancer after preparing its precursor, DTLP. DTLP was shown specifically binding to EGFR and HER2 on cell surface, followed by endocytosis into cytoplasm of pancreatic cancer cells. DTLL significantly promoted apoptosis and cell cycle arrest at G2/M stages and inhibited cell proliferation. Pancreatic tumors of either MIA-paca-2 cell line-derived (CDX) or patient-derived xenograft (PDX) mouse models were significantly regressed in response to DTLL. It suggested that DTLL might be a highly potent bispecific antibody-drug conjugate (ADC)-like agent for pancreatic cancer therapy. LDM is known to function as an antitumor cytotoxic agent by its induction of DNA damage in cancer cells, therefore, DTLL, as its derivative, also showed similar cytotoxicity. However, we found that DTLL might reverse the AKT/mTOR feedback activation induced by LDM at the first time. The results from both in vitro and in vivo experiments suggested that DTLL enhanced DNA damage via EGFR/HER2-dependent blockage of PI3K/AKT/mTOR and PD-L1 signaling pathways in cancer cells, leading to the inhibition of cell proliferation and immunosurveillance escape from pancreatic tumor. Our studies on DTLL functional characterization revealed its novel mechanisms on internal enhancement of DNA damage and implied that DTLL might provide a promising targeted therapeutic strategy for pancreatic cancer.

The evolution into personalized therapies in pancreatic ductal adenocarcinoma: challenges and opportunities

INTRODUCTION

Pancreatic ductal adenocarcinoma (PDAC) is projected to be the second leading cause of cancer related mortality in the United States in 2030, with a 5-year overall survival of less than 10% despite decades of extensive research. Pancreatic cancer is marked by the accumulation of complex molecular changes, complex tumor-stroma interaction, and an immunosuppressive tumor microenvironment. PDAC has proven to be resistant to many cytotoxic, targeted and immunologic treatment approaches. Areas covered: In this paper, we review the major areas of research in PDAC, with highlights on the challenges and areas of opportunity for personalized treatment approaches. Expert commentary: The focus of research in pancreatic cancer has moved away from developing conventional cytotoxic combinations. The marked advances in understanding the molecular biology of this disease especially in the areas of the microenvironment, metabolism, and DNA repair have opened new opportunities for developing novel treatment strategies. Improved understanding of molecular abnormalities allows the development of personalized treatment approaches.

CHD1L Expression Increases Tumor Progression and Acts as a Predictive Biomarker for Poor Prognosis in Pancreatic Cancer

BACKGROUND

The chromodomain helicase/ATPase DNA binding protein 1-like gene (CHD1L) plays a key role in controlling various cellular phenomena, including immune-mediated inflammation, transformation, apoptosis, cell cycle progression, and proliferation.

METHODS

This study investigated the function and clinical significance of CHD1L protein expression in pancreatic cancer (PC). We analyzed CHD1L expression in surgical specimens from 112 PC patients. The correlation between the clinical characteristics and prognosis was also determined. Futhermore, cell proliferation were measured using EDU, and a molecular mechanism of Wnt/β-catenin pathway regulation by CHD1L was explored.

RESULT

CHD1L protein expression was significantly higher in PC patients with regard to the tumor grade, stage, size, differentiation and lymph node status. Increased CHD1L protein expression was significantly associated with poor overall survival. Multivariate analyses revealed that high CHD1L expression was an independent predictive marker for the recurrence and poor prognosis of pancreatic cancer. Furthermore, silencing of CHD1L expression by RNAi effectively abolished the proliferative abilities of CHD1L in vivo and in vitro. We found that the Wnt/β-catenin pathway contributed to the effect of CHD1L-mediated pancreatic cancer proliferation.

CONCLUSION

Taken together, our data provide a novel evidence for the biological and clinical significance of CHD1L as a potential biomarker, and we demonstrate that CHD1L-Wnt/β-catenin might be a novel pathway involved in pancreatic cancer progression.

hENT-1 Expression and Localization Predict Outcome After Adjuvant Gemcitabine in Resected Cholangiocarcinoma Patients

In this letter to the editor, the authors discuss the use of human equilibrative nucleoside transporter 1 (hENT-1) as a biomarker in patients with cholangiocarcinoma. They encourage standardization of techniques to evaluation expression of proteins such as hENT-1 and suggest additional studies investigating the active metabolites of gemcitabine, the use of liquid biopsies, and improved statistical methods.