Nanoparticle albumin-bound-paclitaxel: a limited improvement under the current therapeutic paradigm of pancreatic cancer

BRD9-SMAD2/3 Orchestrates Stemness and Tumorigenesis in Pancreatic Ductal Adenocarcinoma

BACKGROUND & AIMS

The dismal prognosis of pancreatic ductal adenocarcinoma (PDAC) is linked to the presence of pancreatic cancer stem-like cells (CSCs) that respond poorly to current chemotherapy regimens. The epigenetic mechanisms regulating CSCs are currently insufficiently understood, which hampers the development of novel strategies for eliminating CSCs.

METHODS

By small molecule compound screening targeting 142 epigenetic enzymes, we identified that bromodomain-containing protein BRD9, a component of the BAF histone remodeling complex, is a key chromatin regulator to orchestrate the stemness of pancreatic CSCs via cooperating with the TGFβ/Activin-SMAD2/3 signaling pathway.

RESULTS

Inhibition and genetic ablation of BRD9 block the self-renewal, cell cycle entry into G0 phase and invasiveness of CSCs, and improve the sensitivity of CSCs to gemcitabine treatment. In addition, pharmacological inhibition of BRD9 significantly reduced the tumorigenesis in patient-derived xenografts mouse models and eliminated CSCs in tumors from pancreatic cancer patients. Mechanistically, inhibition of BRD9 disrupts enhancer-promoter looping and transcription of stemness genes in CSCs.

CONCLUSIONS

Collectively, the data suggest BRD9 as a novel therapeutic target for PDAC treatment via modulation of CSC stemness.

BRD9-SMAD2/3 orchestrates stemness and tumorigenesis in pancreatic ductal adenocarcinoma

The dismal prognosis of pancreatic ductal adenocarcinoma (PDAC) is linked to the presence of pancreatic cancer stem-like cells (CSCs) that respond poorly to current chemotherapy regimens. By small molecule compound screening targeting 142 epigenetic enzymes, we identified that bromodomain-containing protein BRD9, a component of the BAF histone remodelling complex, is a key chromatin regulator to orchestrate the stemness of pancreatic CSCs via cooperating with the TGFβ/Activin-SMAD2/3 signalling pathway. Inhibition and genetic ablation of BDR9 block the self-renewal, cell cycle entry into G0 phase and invasiveness of CSCs, and improve the sensitivity of CSCs to gemcitabine treatment. In addition, pharmacological inhibition of BRD9 significantly reduced the tumorigenesis in patient-derived xenografts mouse models and eliminated CSCs in tumours from pancreatic cancer patients. Mechanistically, inhibition of BRD9 disrupts enhancer-promoter looping and transcription of stemness genes in CSCs. Collectively, the data suggest BRD9 as a novel therapeutic target for PDAC treatment via modulation of CSC stemness.

Study on the thermal stability of nab-paclitaxel during hyperthermic intraperitoneal chemotherapy

BACKGROUND

Albumin-bound paclitaxel (nab-paclitaxel), as a special targeted preparation of paclitaxel, has the advantages of good curative effect and less side effects in anti-tumor therapy. The existence of the plasma-peritoneal barrier and insufficient blood supply make intravenous drugs hard to reach the peritoneum, while hyperthermic intraperitoneal chemotherapy can solve the difficulty. And compared with systemic medications, HIPEC can also give higher concentrations of chemotherapy drugs in the abdominal cavity, while ensuring lower systemic toxicity. However, at present, there is no relevant report on the clinical study of nab-paclitaxel during intraperitoneal hyperthermic chemotherapy, and its stability under special temperature conditions has not been reported either.

METHODS

In this study, We examined three batches of albumin-bound paclitaxel dissolved in saline at different temperatures (25 °C, 37 °C, 41 °C, 42 °C and 43 °C) for the changes of human serum albumin content, human serum albumin polymer content, related substance content, in-vitro release rate, paclitaxel binding rate and paclitaxel content at different temperatures.

RESULTS

Our results demonstrated that the indicators including human serum albumin content, human serum albumin polymer content, in-vitro release rate, paclitaxel binding rate and paclitaxel content were stable to the several temperatures, except that Taxane (0.1%) and other individual impurities in the determination of related substance content fluctuated comparatively widely with the change of temperature. In addition, only Taxane (0.1%) and 7-Epitaxol (1%) were detected.

CONCLUSIONS

Overall, albumin-bound paclitaxel is relatively stable to different temperatures (25 °C, 37 °C, 41 °C, 42 °C and 43 °C). This study will lay a foundation for further studies on the albumin-bound paclitaxel during hyperthermic intraperitoneal chemotherapy.

Glutamate from nerve cells promotes perineural invasion in pancreatic cancer by regulating tumor glycolysis through HK2 mRNA-m6A modification

BACKGROUND

Perineural invasion (PNI) has a high incidence and poor prognosis in pancreatic ductal adenocarcinoma (PDAC). Our study aimed to identify the underlying molecular mechanism of PNI and propose effective intervention strategies.

METHODS

To observe PNI in vitro and in vivo, a Matrigel/ dorsal root ganglia (DRG) model and a murine sciatic nerve invasion model were respectively used. Magnetic resonance (MR) imaging and positron emission tomography/computed tomography (PET-CT) imaging were also used to evaluate tumor growth. Publicly available datasets and PDAC tissues were used to verify how the nerve cells regulate PDAC cells' PNI.

RESULTS

Our results showed that glutamate from nerve cells could cause calcium influx in PDAC cells via the N-methyl-d-aspartate receptor (NMDAR), subsequently activating the downstream Ca²⁺ dependent protein kinase CaMKII/ERK-MAPK pathway and promoting the mRNA transcription of gene METTL3. Next, METTL3 upregulates the expression of hexokinase 2 (HK2) through N6-methyladenosine (m6A) modification in mRNA, enhances the PDAC cells' glycolysis, and promotes PNI. Furthermore, the IONPs-PEG-scFvCD44v6-scAbNMDAR2B nanoparticles dual targeting CD44 variant isoform 6 (CD44v6) and t NMDAR subunit 2B (NMDAR2B) on PDAC cells were synthesized and verified showing a satisfactory blocking effect on PNI.

CONCLUSIONS

Here, we firstly provided evidence that glutamate from the nerve cells could upregulate the expression of HK2 through mRNA m6A modification via NMDAR2B and downstream Ca²⁺ dependent CaMKII/ERK-MAPK pathway, enhance the glycolysis in PDAC cells, and ultimately promote PNI. In addition, the dual targeting nanoparticles we synthesized were verified to block PNI effectively in PDAC.

Target-Specific Nanoparticle Polyplex Down-Regulates Mutant Kras to Prevent Pancreatic Carcinogenesis and Halt Tumor Progression

Survival from pancreatic cancer is poor because most cancers are diagnosed in the late stages and there are no therapies to prevent the progression of precancerous pancreatic intraepithelial neoplasms (PanINs). Inhibiting mutant KRASG12D, the primary driver mutation in most human pancreatic cancers, has been challenging. The cholecystokinin-B receptor (CCK-BR) is absent in the normal pancreas but becomes expressed in high grade PanIN lesions and is over-expressed in pancreatic cancer making it a prime target for therapy. We developed a biodegradable nanoparticle polyplex (NP) that binds selectively to the CCK-BR on PanINs and pancreatic cancer to deliver gene therapy. PanIN progression was halted and the pancreas extracellular matrix rendered less carcinogenic in P48-Cre/LSL-KrasG12D/+ mice treated with the CCK-BR targeted NP loaded with siRNA to mutant Kras. The targeted NP also slowed proliferation, decreased metastases and improved survival in mice bearing large orthotopic pancreatic tumors. Safety and toxicity studies were performed in immune competent mice after short or long-term exposure and showed no off-target toxicity by histological or biochemical evaluation. Precision therapy with target-specific NPs provides a novel approach to slow progression of advanced pancreatic cancer and also prevents the development of pancreatic cancer in high-risk subjects without toxicity to other tissues.

Targeted Therapy of Lung Adenocarcinoma by the Nanoplatform Based on Milk Exosomes Loaded with Paclitaxel

Lung cancer is the most common cancer throughout the world. Currently, most lung cancer therapies are still limited by serious side effects caused. This paper reports a biocompatible drug delivery system that utilizes milk-derived exosomes to deliver paclitaxel to treat lung adenocarcinoma. First, milk-derived exosomes were modified with integrin α_Vβ₃, α_Vβ₅-binding peptide iRGD so that they could successfully target lung adenocarcinoma cells. Then, iRGD modified exosomes were loaded with paclitaxel (PAC) via electroporation and used for tumor therapy. These modified exosomes proved effective in killing lung adenocarcinoma cells, and the exosome-based nanoplatform showed no obvious toxicity to normal cells. Further more, the exosome-based nanoplatform could effectively penetrate the interior of the 3D tumor sphere, reaching more tumor cells and demonstrating that it is a promising tool for lung adenocarcinoma therapy.

Nanocarriers for pancreatic cancer imaging, treatments, and immunotherapies

Pancreatic tumors are highly desmoplastic and immunosuppressive. Delivery and distribution of drugs within pancreatic tumors are compromised due to intrinsic physical and biochemical stresses that lead to increased interstitial fluid pressure, vascular compression, and hypoxia. Immunotherapy-based approaches, including therapeutic vaccines, immune checkpoint inhibition, CAR-T cell therapy, and adoptive T cell therapies, are challenged by an immunosuppressive tumor microenvironment. Together, extensive fibrosis and immunosuppression present major challenges to developing treatments for pancreatic cancer. In this context, nanoparticles have been extensively studied as delivery platforms and adjuvants for cancer and other disease therapies. Recent advances in nanotechnology have led to the development of multiple nanocarrier-based formulations that not only improve drug delivery but also enhance immunotherapy-based approaches for pancreatic cancer. This review discusses and critically analyzes the novel nanoscale strategies that have been used for drug delivery and immunomodulation to improve treatment efficacy, including newly emerging immunotherapy-based approaches. This review also presents important perspectives on future research directions that will guide the rational design of novel and robust nanoscale platforms to treat pancreatic tumors, particularly with respect to targeted therapies and immunotherapies. These insights will inform the next generation of clinical treatments to help patients manage this debilitating disease and enhance survival rates.

Camouflaged, activatable and therapeutic tandem bionanoreactors for breast cancer theranosis

The one-pot cascade reaction of naturally occurring enzymes is exciting for highly selective complex reaction and biodegradable approaches. Tamoxifen is the main drug against breast cancer for decades and induces an anticancerous effect upon metabolic activation by cytochrome P450 (CYP450). Herein, bi-enzymatic nanoreactors (NRs) are developed as a multimodality platform for smart action against breast tumors. CYP_BM3 of Bacillus magaterium (CYP) is co-confined with glucose oxidase (GOx) where GOx produces H₂O₂ in the presence of glucose that elicits the CYP-mediated transformation of tamoxifen. The scintillating and mesoporous LaF₃:Tb as nanocarrier showed advantages like a wide range of pore size and positive surface charge for efficient loading of enzyme couple, while the smallest pores were available for substrate/product diffusion. The obtained NRs were camouflaged with human serum albumin (HSA) to overcome premature enzyme leaching and provide active stealth properties. The nanocomposite was characterized for physicochemical properties and glucose-mediated sequential catalysis. The in vitro studies demonstrated the cell internalization of NRs in both ER+ and triple-negative breast cancer cell lines and showed significant cytotoxicity. The developed NRs not only improve the outcomes of endocrine therapy in ER+ cells but also synergistically act with oxidation therapy for enhanced therapeutic effect. Importantly, inhibition of triple-negative cells was also achieved. Thus, the development of the new multimodal nanomedicine of the present work should afford new tools towards the theranosis of breast cancer with minimized adverse effects.

A selective drug delivery system based on phospholipid-type nanobubbles for lung cancer therapy

Aim: To develop a micelle-type nanobubble decorated with fluorescein-5-isothiocyanate-conjugated transferrin, with encapsulation of paclitaxel (PTX@FT-NB) for lung cancer treatment. Materials & methods: PTX@FT-NBs were characterized to determine their physicochemical properties, structural stability and cytotoxicity. Lung cancer cell and mouse xenograft tumor models were used to evaluate the therapeutic effectiveness of PTX@FT-NB. Results: The PTX@FT-NBs not only showed selective targeting to lung cancer cells but also inhibited tumor growth significantly via paclitaxel release. Furthermore, paclitaxel-induced microtubule stabilization demonstrated the release of the drug from PTX@FT-NB in the targeted tumor cell both in vitro and in vivo. Conclusion: PTX@FT-NB has the potential as an anticancer nanocarrier against lung cancer cells because of its specific targeting and better drug delivery capacity.

Paclitaxel's Mechanistic and Clinical Effects on Breast Cancer

Paclitaxel (PTX), the most widely used anticancer drug, is applied for the treatment of various types of malignant diseases. Mechanisms of PTX action represent several ways in which PTX affects cellular processes resulting in programmed cell death. PTX is frequently used as the first-line treatment drug in breast cancer (BC). Unfortunately, the resistance of BC to PTX treatment is a great obstacle in clinical applications and one of the major causes of death associated with treatment failure. Factors contributing to PTX resistance, such as ABC transporters, microRNAs (miRNAs), or mutations in certain genes, along with side effects of PTX including peripheral neuropathy or hypersensitivity associated with the vehicle used to overcome its poor solubility, are responsible for intensive research concerning the use of PTX in preclinical and clinical studies. Novelties such as albumin-bound PTX (nab-PTX) demonstrate a progressive approach leading to higher efficiency and decreased risk of side effects after drug administration. Moreover, PTX nanoparticles for targeted treatment of BC promise a stable and efficient therapeutic intervention. Here, we summarize current research focused on PTX, its evaluations in preclinical research and application clinical practice as well as the perspective of the drug for future implication in BC therapy.

The Potential of Combining Tubulin-Targeting Anticancer Therapeutics and Immune Therapy

Cancer immune therapy has recently shown tremendous promise to combat many different cancers. The microtubule is a well-defined and very effective cancer therapeutic target. Interestingly, several lines of evidence now suggest that microtubules are intimately connected to the body’s immune responses. This raises the possibility that the combination of microtubule inhibitors and immune therapy can be a highly effective option for cancer treatments. However, our understanding on this potentially important aspect is still very limited, due in part to the multifaceted nature of microtubule functions. Microtubules are not only involved in maintaining cell morphology, but also a variety of cellular processes, including the movement of secretory vesicles and organelles, intracellular macromolecular assembly, signaling pathways, and cell division. Microtubule inhibitors may be subdivided into two classes: Anti-depolymerization agents such as the taxane family, and anti-polymerization agents such as colchicine and vinka alkaloids. These two different classes may have different effects on immune cell subtypes. Anti-depolymerization agents can not only induce NK cells, but also appear to inhibit T regulatory (Treg) cells. However, different inhibitors may have different functions even among the same class. For example, the doxetaxel anti-depolymerization agent up-regulates cytotoxic T cells, while paclitaxel down-regulates them. Certain anti-polymerization agents such as colchicine appear to down-regulate most immune cell types, while inducing dendritic cell maturation and increasing M1 macrophage population. In contrast, the vinblastine anti-polymerization agent activates many of these cell types, albeit down-regulating Treg cells. In this review, we focus on the various effects of tubulin inhibitors on the activities of the body’s immune system, in the hope of paving the way to develop an effective cancer therapy by combining tubulin-targeting anticancer agents and immune therapy.

KRAS-enhanced macropinocytosis and reduced FcRn-mediated recycling sensitize pancreatic cancer to albumin-conjugated drugs

Pancreatic ductal adenocarcinoma (PDAC) is a dominantly (~95%) KRAS-mutant cancer that has extremely poor prognosis, in part this is due to its strong intrinsic resistance towards almost all therapeutic agents. PDAC relies heavily on KRAS-transformed metabolism, including enhanced macropinocytosis and catabolism of extracellular albumin, to maintain its proliferation and progression. However, it has yet to be validated that whether such transformed metabolism could be exploited for the drug delivery to open therapeutic windows of cytotoxic agents in KRAS-mutant PDAC. In this study, we attempt to answer this question by focusing on the impact of two critical regulators of albumin catabolism, KRAS and the neonatal Fc receptor (FcRn), on the sensitivity of PDAC to doxorubicin (DOX, a model cytotoxic agent) and albumin-conjugated doxorubicin (DOX-ALB). Using cell lines and cell-derived xenografts with different KRAS genotypes and FcRn levels, we demonstrated that KRAS-enhanced macropinocytosis and reduced FcRn expression sensitize PDAC to DOX-ALB but not free DOX. In both in vitro and in vivo comparsion, the DOX-ALB demonstrated ~10 times enlarged therapeutic window compared with free DOX, in PDAC with KRAS mutation and reduced FcRn level, two events appear to occur simultaneously in the investigated PDAC. In summary, we conclude that albumin conjugation is an exploitable drug delivery strategy that significantly opens the therapeutic windows of otherwise undevelopable anti-cancer agents for KRAS-mutant PDAC therapy, and creates a new landscape for clinical evaluation and future translation of such compounds.

Recent advances in "smart" delivery systems for extended drug release in cancer therapy

Advances in nanomedicine have become indispensable for targeted drug delivery, early detection, and increasingly personalized approaches to cancer treatment. Nanoparticle-based drug-delivery systems have overcome some of the limitations associated with traditional cancer-therapy administration, such as reduced drug solubility, chemoresistance, systemic toxicity, narrow therapeutic indices, and poor oral bioavailability. Advances in the field of nanomedicine include “smart” drug delivery, or multiple levels of targeting, and extended-release drug-delivery systems that provide additional methods of overcoming these limitations. More recently, the idea of combining smart drug delivery with extended-release has emerged in hopes of developing highly efficient nanoparticles with improved delivery, bioavailability, and safety profiles. Although functionalized and extended-release drug-delivery systems have been studied extensively, there remain gaps in the literature concerning their application in cancer treatment. We aim to provide an overview of smart and extended-release drug-delivery systems for the delivery of cancer therapies, as well as to introduce innovative advancements in nanoparticle design incorporating these principles. With the growing need for increasingly personalized medicine in cancer treatment, smart extended-release nanoparticles have the potential to enhance chemotherapy delivery, patient adherence, and treatment outcomes in cancer patients.

SpheroidSim-Preliminary evaluation of a new computational tool to predict the influence of cell cycle time and phase fraction on spheroid growth

BACKGROUND

There is a relative paucity of research that integrates materials science and bioengineering with computational simulations to decipher the intricate processes promoting cancer progression. Therefore, a first-generation computational model, SpheroidSim, was developed that includes a biological data set derived from a bioengineered spheroid model to obtain a quantitative description of cell kinetics.

RESULTS

SpheroidSim is a 3D agent-based model simulating the growth of multicellular cancer spheroids. Cell cycle time and phases mathematically motivated the population growth. SpheroidSim simulated the growth dynamics of multiple spheroids by individually defining a collection of specific phenotypic traits and characteristics for each cell. Experimental data derived from a hydrogel-based spheroid model were fit to the predictions providing insight into the influence of cell cycle time (CCT) and cell phase fraction (CPF) on the cell population. A comparison of the number of active cells predicted for each analysis showed that the value and method used to define CCT had a greater effect on the predicted cell population than CPF. The model predictions were similar to the experimental results for the number of cells, with the predicted total number of cells varying by 8% and 12%, respectively, compared to the experimental data.

CONCLUSIONS

SpheroidSim is a first step in developing a biologically based predictive tool capable of revealing fundamental elements in cancer cell physiology. This computational model may be applied to study the effect of the microenvironment on spheroid growth and other cancer cell types that demonstrate a similar multicellular clustering behavior as the population develops. © 2018 American Institute of Chemical Engineers Biotechnol. Prog., 34:1335-1343, 2018.

Should We Keep Walking along the Trail for Pancreatic Cancer Treatment? Revisiting TNF-Related Apoptosis-Inducing Ligand for Anticancer Therapy

Despite recent advances in oncology, diagnosis, and therapy, treatment of pancreatic ductal adenocarcinoma (PDAC) is still exceedingly challenging. PDAC remains the fourth leading cause of cancer-related deaths worldwide. Poor prognosis is due to the aggressive growth behavior with early invasion and distant metastasis, chemoresistance, and a current lack of adequate screening methods for early detection. Consequently, novel therapeutic approaches are urgently needed. Many hopes for cancer treatment have been placed in the death ligand tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) since it was reported to induce apoptosis selectively in tumor cells in vitro and in vivo. TRAIL triggers apoptosis through binding of the trans-membrane death receptors TRAIL receptor 1 (TRAIL-R1) also death receptor 4 (DR4) and TRAIL receptor 2 (TRAIL-R2) also death receptor 5 (DR5) thereby inducing the formation of the death-inducing signaling complex (DISC) and activation of the apoptotic cascade. Unlike chemotherapeutics, TRAIL was shown to be able to induce apoptosis in a p53-independent manner, making TRAIL a promising anticancer approach for p53-mutated tumors. These cancer-selective traits of TRAIL led to the development of TRAIL-R agonists, categorized into either recombinant variants of TRAIL or agonistic antibodies against TRAIL-R1 or TRAIL-R2. However, clinical trials making use of these agonists in various tumor entities including pancreatic cancer were disappointing so far. This is thought to be caused by TRAIL resistance of numerous primary tumor cells, an insufficient agonistic activity of the drug candidates tested, and a lack of suitable biomarkers for patient stratification. Nevertheless, recently gained knowledge on the biology of the TRAIL-TRAIL-R system might now provide the chance to overcome intrinsic or acquired resistance against TRAIL and TRAIL-R agonists. In this review, we summarize the status quo of clinical studies involving TRAIL-R agonists for the treatment of pancreatic cancer and critically discuss the suitability of utilizing the TRAIL-TRAIL-R system for successful treatment.

Nanoformulations for combination or cascade anticancer therapy

Nanoparticle drug formulations have been extensively investigated, developed, and in some cases, approved by the Food and Drug Administration (FDA). Synergistic combinations of drugs having distinct tumor-inhibiting mechanisms and non-overlapping toxicity can circumvent the issue of treatment resistance and may be essential for effective anti-cancer therapy. At the same time, co-delivery of a combined regimen by a single nanocarrier presents a challenge due to differences in solubility, molecular weight, functional groups and encapsulation conditions between the two drugs. This review discusses cellular and microenvironment mechanisms behind treatment resistance and nanotechnology-based solutions for effective anti-cancer therapy. Co-loading or cascade delivery of multiple drugs using of polymeric nanoparticles, polymer-drug conjugates and lipid nanoparticles will be discussed along with lipid-coated drug nanoparticles developed by our lab and perspectives on combination therapy.

Cervical Cancer Patient-Derived Orthotopic Xenograft (PDOX) Is Sensitive to Cisplatinum and Resistant to Nab-paclitaxel

BACKGROUND

Cervical cancer is a world-wide problem that requires transformative therapeutic strategies. We have previously developed patient-derived orthotopic xenograft (PDOX) nude-mouse models of this disease. In the present report, we demonstrate that the standard drug, cisplatinum (CDDP), is highly-effective while the new, highly-touted agent, nab-paclitaxel (NAB-PTX) is ineffective.

MATERIALS AND METHODS

Cervical PDOX tumors were grown on the cervix of nude mice for 4 weeks after surgical orthotopic implantation (SOI). Tumors were treated with CDDP or NAB-PTX.

RESULTS

H&E staining demonstrated that the PDOX tumor recapitulated the original patient tumor. CDDP was highly-effective. One tumor that was treated with CDDP completely regressed. CDDP-treated tumors were smaller (tumor volume ratio: 0.42±0.36) than the control group (tumor volume ratio: 3.47±1.66) (p<0.01). In contrast, NAB-PTX did not show significant efficacy on the cervical cancer PDOX model (tumor volume ratio: 2.85±1.45) (p=0.47). CDDP-treated tumor weight (50±50 mg) was significantly less than control (238±114 mg) (p<0.01). NAB-PTX-treated tumors were not reduced in weight (246±136 mg) compared to control (p=0.91). There were no significant differences in mouse body weight between groups. Histological evaluation demonstrated that CDDP-treated tumors were fibrotic with scattered squamous cell nests compared to control or NAB-PTX-treated tumors.

CONCLUSION

The results of the present study demonstrate the power of PDOX models of cervical cancer to distinguish efficacy of potential therapeutics for individual patients with this disease.

Nanotechnology for delivery of gemcitabine to treat pancreatic cancer

Pancreatic cancer (PC) is one of the most deadly and quickly fatal human cancers with a 5-year mortality rate close to 100%. Its prognosis is very poor, mainly because of its hostile biological behavior and late onset of symptoms for clinical diagnosis; these bring limitations on therapeutic interventions. Factors contributing for the difficulties in treating PC include: high rate of drug resistance, fast metastasis to different organs, poor prognosis and relapse of the tumor after therapy. After being approved by US FDA 1997, Gemcitabine (Gem) is the first line and the gold standard drug for all stages of advanced PC till now. However, its efficacy is unsatisfactory, mainly due to; its chemical instability and poor cellular uptake, resulting in an extremely short half-life and low bioavailability. To solve this drawbacks and increase the therapeutic outcome important progress has been achieved in the field of nanotechnology and offers a promising and effective alternative. This review mainly focus on the most commonly investigated nanoparticle (NP) delivery systems of Gem for PC treatment and the latest progresses achieved. Novel nanocarriers with better tumor targeting efficiencies and maximum treatment outcome to treat this deadly due are given much attention.

Nanomedicine strategies to overcome the pathophysiological barriers of pancreatic cancer

Pancreatic ductal adenocarcinoma (PDAC) is one of the leading causes of cancer- related deaths. PDAC remains one of the most difficult-to-treat cancers, owing to its unique pathobiological features: a nearly impenetrable desmoplastic stroma, and hypovascular and hypoperfused tumour vessels render most treatment options largely ineffective. Progress in understanding the pathobiology and signalling pathways involved in disease progression is helping researchers to develop novel ways to fight PDAC, including improved nanotechnology-based drug-delivery platforms that have the potential to overcome the biological barriers of the disease that underlie persistent drug resistance. So-called 'nanomedicine' strategies have the potential to enable targeting of the Hedgehog-signalling pathway, the autophagy pathway, and specific RAS-mutant phenotypes, among other pathological processes of the disease. These novel therapies, alone or in combination with agents designed to disrupt the pathobiological barriers of the disease, could result in superior treatments, with increased efficacy and reduced off-target toxicities compared with the current standard-of-care regimens. By overcoming drug-delivery challenges, advances can be made in the treatment of PDAC, a disease for which limited improvement in overall survival has been achieved over the past several decades. We discuss the approaches to nanomedicine that have been pursued to date and those that are the focus of ongoing research, and outline their potential, as well as the key challenges that must be overcome.

Folate-conjugated nanoparticles as a potent therapeutic approach in targeted cancer therapy

The selective and efficient drug delivery to tumor cells can remarkably improve different cancer therapeutic approaches. There are several nanoparticles (NPs) which can act as a potent drug carrier for cancer therapy. However, the specific drug delivery to cancer cells is an important issue which should be considered before designing new NPs for in vivo application. It has been shown that cancer cells over-express folate receptor (FR) in order to improve their growth. As normal cells express a significantly lower levels of FR compared to tumor cells, it seems that folate molecules can be used as potent targeting moieties in different nanocarrier-based therapeutic approaches. Moreover, there is evidence which implies folate-conjugated NPs can selectively deliver anti-tumor drugs into cancer cells both in vitro and in vivo. In this review, we will discuss about the efficiency of different folate-conjugated NPs in cancer therapy.