Gluing GAP to RAS Mutants: A New Approach to an Old Problem in Cancer Drug Development.

Mutated genes may lead to cancer development in numerous tissues. While more than 600 cancer-causing genes are known today, some of the most widespread mutations are connected to the RAS gene; RAS mutations are found in approximately 25% of all human tumors. Specifically, KRAS mutations are involved in the three most lethal cancers in the U.S., namely pancreatic ductal adenocarcinoma, colorectal adenocarcinoma, and lung adenocarcinoma. These cancers are among the most difficult to treat, and they are frequently excluded from chemotherapeutic attacks as hopeless cases. The mutated KRAS proteins have specific three-dimensional conformations, which perturb functional interaction with the GAP protein on the GAP-RAS complex surface, leading to a signaling cascade and uncontrolled cell growth. Here, we describe a gluing docking method for finding small molecules that bind to both the GAP and the mutated KRAS molecules. These small molecules glue together the GAP and the mutated KRAS molecules and may serve as new cancer drugs for the most lethal, most difficult-to-treat, carcinomas. As a proof of concept, we identify two new, drug-like small molecules with the new method; these compounds specifically inhibit the growth of the PANC-1 cell line with KRAS mutation G12D in vitro and in vivo. Importantly, the two new compounds show significantly lower IC50 and higher specificity against the G12D KRAS mutant human pancreatic cancer cell line PANC-1, as compared to the recently described selective G12D KRAS inhibitor MRTX-1133.

Current trends in the diagnosis of pancreatic cancer.

Pancreatic ductal adenocarcinoma (PDAC) is a dreaded malignancy with a dismal 5-year survival rate despite maximal efforts on optimizing treatment strategies. Currently, early detection is considered to be the most effective way to improve survival as radical resection is the only potential cure. PDAC is often divided into four categories based on the extent of disease: resectable, borderline resectable, locally advanced, and metastatic. Unfortunately, the majority of patients are diagnosed with locally advanced or metastatic disease, which renders them ineligible for curative resection. This is mainly due to the lack of or vague symptoms while the disease is still localized, although appropriate utilization and prompt availability of adequate diagnostic tools is also critical given the aggressive nature of the disease. A cost-effective biomarker with high specificity and sensitivity allowing early detection of PDAC without the need for advanced or invasive methods is still not available. This leaves the diagnosis dependent on radiodiagnostic methods or endoscopic ultrasound. Here we summarize the latest epidemiological data, risk factors, clinical manifestation, and current diagnostic trends and implications of PDAC focusing on serum biomarkers and imaging modalities. Additionally, up-to-date management and therapeutic algorithms are outlined.

A perylene derivative regulates HIF-1α and Stat3 signaling pathways.

It is becoming increasingly evident that improving the cure rate of many cancers will require treatment regimens hit more than one validated tumor targets. Developing an anti-cancer agent that targets two oncoproteins simultaneously is a promising strategy for accomplishing this goal. It would be expected to promote drug efficacy, reduce therapy-resistant without introducing additional toxic side effects. HIF-1α is a key regulator of the cellular response to hypoxia and is involved in tumor angiogenesis and cancer cell survival, glucose metabolism, and invasion. Stat3 has several oncogenic functions, including suppression of anti-tumor immune responses and promotion of inflammation. Recently, we have identified the perylene derivative, TEL03, as a dual inhibitor that targets both HIF-1α and Stat3. TEL03 blocks the expression of both HIF-1α and Stat3, regulated oncogenes (e.g., Bcl-2, VEGF, Glut1, and others) in cancer cells, and induces cancer cell apoptosis. The results demonstrated that: (i) TEL03 blocks Stat3 phosphorylation, and inhibits Stat3 transcriptional activity; and (ii) interferes the binding of HIF-1α to p300/CBP inducing its degradation by proteasomes under hypoxic conditions. Our in vivo tests showed that as a dual inhibitor, TEL03 dramatically inhibited tumor growth, and provided the evidence that targeting both HIF-1α and Stat3 simultaneously could be a promising strategy for breast and pancreatic cancer therapies.

Study on tumour cell-derived hybrid exosomes as dasatinib nanocarriers for pancreatic cancer therapy.

Pancreatic ductal adenocarcinoma (PDAC) is one of the leading causes of cancer-related death. Therefore, we intend to explore novel strategies against PDAC. The exosomes-based biomimetic nanoparticle is an appealing candidate served as a drug carrier in cancer treatment, due to its inherit abilities. In the present study, we designed dasatinib-loaded hybrid exosomes by fusing human pancreatic cancer cells derived exosomes with dasatinib-loaded liposomes, followed by characterization for particle size (119.9 ± 6.10 nm) and zeta potential (-11.45 ± 2.24 mV). Major protein analysis from western blot techniques reveal the presence of exosome marker proteins CD9 and CD81. PEGylated hybrid exosomes showed pH-sensitive drug release in acidic condition, benefiting drug delivery to acidic cancer environment. Dasatinib-loaded hybrid exosomes exhibited significantly higher uptake rates and cytotoxicity to parent PDAC cells by two-sample t-test or by one-way ANOVA analysis of variance, as compared to free drug or liposomal formulations. The results from our computational analysis demonstrated that the drug-likeness, ADMET, and protein-ligand binding affinity of dasatinib are verified successfully. Cancer derived hybrid exosomes may serve as a potential therapeutic candidate for pancreatic cancer treatment.

Regulating the properties of XQ-2d for targeted delivery of therapeutic agents to pancreatic cancers.

Enhanced recognition ability, cell uptake capacity, and biostability are characteristics attributed to aptamer-based targeted anticancer agents, and are possibly associated with increased accumulation at the tumor site, improved therapeutic efficacy and reduced negative side effects. Herein, a phosphorothioate backbone modification strategy was applied to regulate the biomedical properties of pancreatic cancer cell-targeting aptamer for efficient in vivo drug delivery. Specifically, the CD71- targeting aptamer XQ-2d was modified into a fully thio-substituted aptamer S-XQ-2d, improving the plasma stability of S-XQ-2d and mitomycin C (MMC)-functionalized S-XQ-2d (MFSX), thus considerably prolonging their half-life in mice. Moreover, the binding and uptake capacities of S-XQ-2d were significantly enhanced. MFSX showed the same level of cytotoxicity as that of MMC against targeted cancer cells, but lower toxicity to non-targeted cells, highlighting its specificity and biosafety. Brief mechanistic studies demonstrated that XQ-2d and S-XQ-2d had different interaction modes and internalization pathways with the targeted cells.

Single-cell sequencing in pancreatic cancer research: A deeper understanding of heterogeneity and therapy.

Pancreatic cancer, including pancreatic ductal adenocarcinomas (PDACs), is a malignant tumor with characteristics of tumor-stroma interactions. Patients often have a poor prognosis and a poor long-term survival rate. In recent years, rapidly-developing single-cell sequencing techniques have been used to analyze cell populations at a single-cell resolution, so that it is now possible to have a more in-depth and clearer understanding of the genetic composition of pancreatic cancer. In this review, we provide an overview of the current single-cell sequencing techniques and their applications in the exploration of intratumoral heterogeneity, the tumor microenvironment, therapy resistance, and novel treatments. Our hope is to provide new insight into the potential of precision therapy, which will perhaps one day lead to significant advances in PDAC treatment.

Gemcitabine and rapamycin-loaded mixed polymeric thermogel for metastatic pancreatic cancer therapy.

Pancreatic ductal adenocarcinoma (PDAC) is the 4th leading cause of cancer-related death and has a poor 5-year overall survival. The superior therapeutic benefits of combination or co-administration of drugs as intraperitoneal chemotherapy have increased interest in developing strategies to deliver chemotherapeutic agents to patients safely. In this study, we prepared a gel comprising the thermosensitive poly(lactide-co-glycolide)-b-poly(ethylene glycol)-b-poly(lactide-co-glycolide) (PLGA-PEG-PLGA) polymer and gemcitabine (GEM), which is currently used as the primary chemotherapy for PDAC and rapamycin (RAPA), a mammalian TOR (mTOR) inhibitor, to deliver the drug through intraperitoneal injection. We performed in vitro cytotoxicity experiments to verify the synergistic effects of the two drugs at different molar ratios and characterized the physicochemical properties of the GEM, RAPA, and GEM/RAPA-loaded thermosensitive PLGA-PEG-PLGA gels, hereafter referred to as (g(G), g(R), and g(GR)), respectively. The g(GR) comprising PLGA-PEG-PLGA polymer (25% w/v) and GEM and RAPA at a molar ratio of 11:1 showed synergism and was optimized. An in vitro cytotoxicity assay was performed by treating Panc-1-luc2 tumor spheroids with g(G), g(R), or g(GR). The g(GR) treatment group showed a 2.75-fold higher inhibition rate than the non-treated (NT) and vehicle-treated groups. Furthermore, in vivo drug release assay in mice by intraperitoneal injection of g(G), g(R), or g(GR) showed a more rapid release rate of GEM than RAPA, similar to the in vitro release pattern. The drugs in the gel were released faster in vivo than in vitro and degraded in 48 h. In addition, g(GR) showed the highest anti-tumor efficacy with no toxicity to mice. These results provide evidence for the safety and efficacy of g(GR) for intraperitoneal drug delivery. This study will assist in developing and clinically administering topical anti-cancer formulations.

Disulfide Bond-Based SN38 Prodrug Nanoassemblies with High Drug Loading and Reduction-Triggered Drug Release for Pancreatic Cancer Therapy.

Purpose: Chemotherapy is a significant and effective therapeutic strategy that is frequently utilized in the treatment of cancer. Small molecular prodrug-based nanoassemblies (SMPDNAs) combine the benefits of both prodrugs and nanomedicine into a single nanoassembly with high drug loading, increased stability, and improved biocompatibility. Methods: In this study, a disulfide bond inserted 7-ethyl-10-hydroxycamptothecin (SN38) prodrug was rationally designed and then used to prepare nanoassemblies (SNSS NAs) that were selectively activated by rich glutathione (GSH) in the tumor site. The characterization of SNSS NAs and the in vitro and in vivo evaluation of their antitumor effect on a pancreatic cancer model were performed. Results: In vitro findings demonstrated that SNSS NAs exhibited GSH-induced SN38 release and cytotoxicity. SNSS NAs have demonstrated a passive targeting effect on tumor tissues, a superior antitumor effect compared to irinotecan (CPT-11), and satisfactory biocompatibility with double dosage treatment. Conclusion: The SNSS NAs developed in this study provide a new method for the preparation of SN38-based nano-delivery systems with improved antitumor effect and biosafety.

Pevonedistat Suppresses Pancreatic Cancer Growth via Inactivation of the Neddylation Pathway.

BACKGROUND: The neddylation pathway is aberrantly overactivated in multiple human cancers and has been indicated as an effective target for anticancer therapy in clinical trials. We aimed to study whether the neddylation pathway is upregulated in pancreatic cancer and whether pevonedistat, a first-in-class anticancer agent specifically targeting this pathway, will suppress cancer tumorigenesis and progression. METHODS: We evaluated the expression pattern of neddylation pathway components in 179 pancreatic adenocarcinoma (PAAD) compared with 171 normal tissues from The Cancer Genome Atlas (TCGA) dataset and further assessed PAAD patient prognosis with high neddylation pathway expression via Gene Expression Profiling Interactive Analysis (GEPIA). We then analyzed malignant cancer phenotypes both in vitro and in vivo, as well as intrinsic molecular mechanisms upon pevonedistat treatment. RESULTS: We found that the neddylation pathway was hyperactivated in pancreatic cancer. Patients with high neddylation pathway expression exhibited worse prognoses. Pevonedistat significantly inhibited the cancer cell cycle, cell growth, and proliferation; increased cell apoptosis; and decreased cancer cell xenografts in a mouse model. Mechanistically, pevonedistat treatment and the siRNA knockdown neddylation pathway were able to remarkably induce the accumulation of Wee1, p27, and p21. Further mechanistic studies revealed that pevonedistat mainly impaired the ubiquitination level and delayed the protein degradation of Wee1, p27, and p21. CONCLUSIONS: Our results showed that pevonedistat targeted the overexpression of the neddylation pathway in pancreatic cancer to induce cell growth suppression by inducing the accumulation of the cell cycle regulators Wee1, p27, and p21, which provides sound evidence for the clinical trial of pevonedistat for pancreatic cancer therapy.

Smart Design of Mitochondria-Targeted and ROS-Responsive CPI-613 Delivery Nanoplatform for Bioenergetic Pancreatic Cancer Therapy.

Mitochondria, as the powerhouse of most cells, are not only responsible for the generation of adenosine triphosphate (ATP) but also play a decisive role in the regulation of apoptotic cell death, especially of cancer cells. Safe potential delivery systems which can achieve organelle-targeted therapy are urgently required. In this study, for effective pancreatic cancer therapy, a novel mitochondria-targeted and ROS-triggered drug delivery nanoplatform was developed from the TPP-TK-CPI-613 (TTCI) prodrug, in which the ROS-cleave thioketal functions as a linker connecting mitochondrial targeting ligand TPP and anti-mitochondrial metabolism agent CPI-613. DSPE-PEG2000 was added as an assistant component to increase accumulation in the tumor via the EPR effect. This new nanoplatform showed effective mitochondrial targeting, ROS-cleaving capability, and robust therapeutic performances. With active mitochondrial targeting, the formulated nanoparticles (TTCI NPs) demonstrate much higher accumulation in mitochondria, facilitating the targeted delivery of CPI-613 to its acting site. The results of in vitro antitumor activity and cell apoptosis revealed that the IC50 values of TTCI NPs in three types of pancreatic cancer cells were around 20~30 µM, which was far lower than those of CPI-613 (200 µM); 50 µM TTCI NPs showed an increase in apoptosis of up to 97.3% in BxPC3 cells. Therefore, this mitochondria-targeted prodrug nanoparticle platform provides a potential strategy for developing safe, targeting and efficient drug delivery systems for pancreatic cancer therapy.

Mechanical characterization of a fiberoptic microneedle device for controlled delivery of fluids and photothermal excitation.

Current clinical approaches for treating pancreatic cancer have been demonstrated as ineffective at improving midterm survival. A primary obstacle to local drug delivery is the desmoplastic nature of the peritumoral environment, which acts as a significant barrier to circulating macromolecules. To address this need, our group presents a sharp fiberoptic microcatheter capable of accessing the pancreas through transduodenal endoscope and penetrating a tumor to locally co-deliver photothermal and fluid-based therapies. Experiments sought to characterize the mechanical penetration capabilities and fluid mechanics of the fiberoptic microneedle design. A refined off-center fusion splicing technique was developed for joining a multimode fiber to the annular core of a light-guiding capillary, allowing light transmission with minimal optical loss. A novel and frugal technique for assessing the penetration force of the microneedle was conducted in a bovine gelatin tissue phantom with a Young's modulus stiffer than the high range for pancratic tissue or tumor. Buckling forces for different microneedle lengths were measured and compared against theoretical values obtained from Euler's Critical Load equation under fixed-pinned column conditions. Hydraulic resistance of different capillary lengths was evaluated and compared against the theoretical values from Hagen-Poiseuille's law, allowing assessment of contributions from different segments of the device. The results demonstrated that the microcatheter can robustly and repeatably penetrate a soft tissue phantom chosen to be a conservative model of pancreatic tissue for penetration properties. Experiments showed that a 1.5 N insertion force was required for phantom penetration with a 45° beveled needle at a 5 mm unsupported length, while the critical buckling load was measured to be approximately 4 N. In addition, the design was demonstrated to efficiently transport 1064 nm light and aqueous fluids with a 70-75% light coupling efficiency and 12,200 Pa.s/µl hydraulic resistance, respectively. These findings motivate the FMD's further development as a treatment platform for pancreatic cancer.

Combination of Anti-miRNAs Oligonucleotides with Low Amounts of Chemotherapeutic Agents for Pancreatic Cancer Therapy.

Pancreatic ductal adenocarcinoma (PDAC) is the most predominant type of pancreatic cancer and presents one of the highest mortality rates when compared with other carcinomas. The absence of efficient treatment options for PDAC prompted us to investigate whether microRNA inhibition, combined or not with chemotherapeutic agents, would constitute a promising therapeutic approach for this disease. In this chapter, we describe several methods and procedures that can be used to evaluate the potential of new therapeutic strategies involving oligonucleotides against overexpressed microRNAs, in PDAC, either alone or in combination with low amounts of chemotherapeutic drugs.

Dual Enzymatic Reaction-Assisted Gemcitabine Delivery Systems for Programmed Pancreatic Cancer Therapy.

Dual enzymatic reactions were introduced to fabricate programmed gemcitabine (GEM) nanovectors for targeted pancreatic cancer therapy. Dual-enzyme-sensitive GEM nanovectors were prepared by conjugation of matrix metalloproteinase-9 (MMP-9) detachable poly(ethylene glycol) (PEG), cathepsin B-cleavable GEM, and targeting ligand CycloRGD to CdSe/ZnS quantum dots (QDs). The GEM nanovectors decorated with a PEG corona could avoid nonspecific interactions and exhibit prolonged blood circulation time. After GEM nanovectors were accumulated in tumor tissue by the enhanced permeability and retention (EPR) effect, the PEG corona can be removed by overexpressed MMP-9 in tumor tissue and RGD would be exposed, which was capable of facilitating cellular internalization. Once internalized into pancreatic cancer cells, the elevated lysosomal cathepsin B could further promote the release of GEM. By employing dual enzymatic reactions, the GEM nanovectors could achieve prolonged circulation time while maintaining enhanced cellular internalization and effective drug release. The proposed mechanism of the dual enzymatic reaction-assisted GEM delivery system was fully investigated both in vitro and in vivo. Meanwhile, compared to free GEM, the deamination of GEM nanovectors into inactive 2',2'-difluorodeoxyuridine (dFdU) could be greatly suppressed, while the concentration of the activated form of GEM (gemcitabine triphosphate, dFdCTP) was significantly increased in tumor tissue, thus exhibiting superior tumor inhibition activity with minimal side effects.