Resistance to tyrosine kinase inhibitors promotes renal cancer progression through MCPIP1 tumor-suppressor downregulation and c-Met activation

Cancer-Associated Fibroblast-Derived FGF7 Promotes Clear Cell Renal Cell Carcinoma Progression and Macrophage Infiltration

As the predominant stromal cells in the ccRCC surrounding environment, cancer-associated fibroblasts (CAFs) have been established as supportive of tumor growth. However, the detailed molecular mechanisms underlying the supporting role of CAFs in ccRCC have not been well characterized. Evidence from the clustering consensus analysis, single-cell analysis, and the experimental results illustrate that CAF-derived FGF7 plays a crucial role as a signaling mediator between CAFs and ccRCC tumor cells. Mechanistically, CAF-derived FGF7 triggers AKT activation to promote cell growth and cell invasion of ccRCC tumor cells. As a response, ccRCC tumor cells stimulate STAT3-mediated transcriptional regulation, directly increasing FGF7 expression at the chromatin level in CAFs. Moreover, there exists a positive clinical correlation between the abundance of CAFs, FGF7 expression, and the infiltration of M2 type macrophages. The RENCA in vivo mouse model also confirmed that FGF7 depletion could impede RCC development by reducing the recruitment of M2 type macrophages. Overall, this study delineates a key signaling axis governing the crosstalk between CAFs and ccRCC tumor cells, highlighting FGF7 as a promising therapeutic target of ccRCC.

Xanthohumol overcomes osimertinib resistance via governing ubiquitination-modulated Ets-1 turnover

Non-small cell lung cancer (NSCLC) is a prevalent and fatal malignancy with a significant global impact. Recent advancements have introduced targeted therapies like tyrosine kinase inhibitors (TKIs) such as osimertinib, which have improved patient outcomes, particularly in those with EGFR mutations. Despite these advancements, acquired resistance to TKIs remains a significant challenge. Hence, one of the current research priorities is understanding the resistance mechanisms and identifying new therapeutic targets to improve therapeutic efficacy. Herein, we identified high expression of c-Met in osimertinib-resistant NSCLC cells, and depletion of c-Met significantly inhibited the proliferation of osimertinib-resistant cells and prolonged survival in mice, suggesting c-Met as an attractive therapeutic target. To identify effective anti-tumor agents targeting c-Met, we screened a compound library containing 641 natural products and found that only xanthohumol exhibited potent inhibitory effects against osimertinib-resistant NSCLC cells. Moreover, combination treatment with xanthohumol and osimertinib sensitized osimertinib-resistant NSCLC cells to osimertinib both in vitro and in vivo. Mechanistically, xanthohumol disrupted the interaction between USP9X and Ets-1, and inhibited the phosphorylation of Ets-1 at Thr38, promoting its degradation, thereby targeting the Ets-1/c-Met signaling axis and inducing intrinsic apoptosis in osimertinib-resistant NSCLC cells. Overall, the research highlights the critical role of targeting c-Met to address osimertinib resistance in NSCLC. By demonstrating the efficacy of xanthohumol in overcoming resistance and enhancing therapeutic outcomes, this study provides valuable insights and potential new strategies for improving the clinical management of NSCLC.

Integrative analysis of single-cell and bulk multi-omics data to reveal subtype-specific characteristics and therapeutic strategies in clear cell renal cell carcinoma patients

Background: Kidney renal clear cell carcinoma (KIRC) is the most prevalent subtype of malignant renal cell carcinoma and is well known as a common genitourinary cancer. Stratifying tumors based on heterogeneity is essential for better treatment options. Methods: In this study, consensus clusters were constructed based on gene expression, DNA methylation, and gene mutation data, which were combined with multiple clustering algorithms. After identifying two heterogeneous subtypes, we analyzed the molecular characteristics, immunotherapy response, and drug sensitivity differences of each subtype. And we further integrated bulk data and single-cell RNA sequencing (scRNA-Seq) data to infer the immune cell composition and malignant tumor cell proportion of subtype-related cell subpopulations. Results: Among the two identified consensus subtypes (CS1 and CS2), CS1 was enriched in more inflammation-related and oncogenic pathways than CS2. Simultaneously, CS1 showed a worse prognosis and we found more copy number variations and BAP1 mutations in CS1. Although CS1 had a high immune infiltration score, it exhibited high expression of suppressive immune features. Based on the prediction of immunotherapy and drug sensitivity, we inferred that CS1 may respond poorly to immunotherapy and be less sensitive to targeted drugs. The analysis of bulk data integrated with single-cell data further reflected the high expression of inhibitory immune features in CS1 and the high proportion of malignant tumor cells. And CS2 contained a large number of plasmacytoid B cells, presenting an activated immune microenvironment. Finally, the robustness of our subtypes was successfully validated in four external datasets. Conclusion: In summary, we conducted a comprehensive analysis of multi-omics data with 10 clustering algorithms to reveal the molecular characteristics of KIRC patients and validated the relevant conclusions by single-cell analysis and external data. Our findings discovered new KIRC subtypes and may further guide personalized and precision treatments.

Slipping Away: Slippage in Hazard Ratios Over Datacuts and Its Impact on Immuno-oncology Combination Economic Evaluations

OBJECTIVES

This study examines the impact of slippage in hazard ratios (tending toward the null over subsequent datacuts) for overall survival for combination treatment with a PD-(L)-1 inhibitor and a tyrosine kinase inhibitor in advanced renal cell carcinoma.

METHODS

Four trials' Kaplan-Meier curves were digitized over several datacuts and fitted with standard parametric curves. Accuracy and consistency of early data projections were calculated versus observed restricted mean survival time and fitted lifetime survival from the longest follow-up datacut. The change in economically justifiable price (eJP) was calculated fitting the same curve to both arms, using an assumed average utility of 0.7 and willingness-to-pay threshold of £30 000 per quality-adjusted life-year. The eJP represents the lifetime justifiable price increment for the new treatment, including differences in drug-, administration-, and disease-related costs.

RESULTS

Slippage in hazard ratios was observed in trials with longer follow-up, potentially influenced by subsequent PD-(L)-1 use after tyrosine kinase inhibitor monotherapy, early stoppage of PD-(L)-1, and development of resistance. Lognormal and log-logistic curves were more likely to overpredict the observed result; Gompertz and gamma underpredicted. Statistical measures of goodness of fit did not select the curves that resulted in the RMST closest to what was observed in the final data cut. Large differences in incremental mean life-years were observed between even the penultimate and final datacuts for most of the fitted curves, meaningfully affecting the eJP.

CONCLUSIONS

This work demonstrates the challenge in predicting treatment benefits with novel therapies using immature data. Incorporating information on the impact of subsequent treatment is likely to play a key role in improving predictions.

Therapeutic importance and diagnostic function of circRNAs in urological cancers: from metastasis to drug resistance

Circular RNAs (circRNAs) are a member of non-coding RNAs with no ability in encoding proteins and their aberrant dysregulation is observed in cancers. Their closed-loop structure has increased their stability, and they are reliable biomarkers for cancer diagnosis. Urological cancers have been responsible for high mortality and morbidity worldwide, and developing new strategies in their treatment, especially based on gene therapy, is of importance since these malignant diseases do not respond to conventional therapies. In the current review, three important aims are followed. At the first step, the role of circRNAs in increasing or decreasing the progression of urological cancers is discussed, and the double-edged sword function of them is also highlighted. At the second step, the interaction of circRNAs with molecular targets responsible for urological cancer progression is discussed, and their impact on molecular processes such as apoptosis, autophagy, EMT, and MMPs is highlighted. Finally, the use of circRNAs as biomarkers in the diagnosis and prognosis of urological cancer patients is discussed to translate current findings in the clinic for better treatment of patients. Furthermore, since circRNAs can be transferred to tumor via exosomes and the interactions in tumor microenvironment provided by exosomes such as between macrophages and cancer cells is of importance in cancer progression, a separate section has been devoted to the role of exosomal circRNAs in urological tumors.

Identification of PI3K-AKT Pathway-Related Genes and Construction of Prognostic Prediction Model for ccRCC

BACKGROUND

Clear cell renal cell carcinoma (ccRCC), the predominate histological type of renal cell carcinoma (RCC), has been extensively studied, with poor prognosis as the stage increases. Research findings consistently indicated that the PI3K-Akt pathway is commonly dysregulated across various cancer types, including ccRCC. Targeting the PI3K-Akt pathway held promise as a potential therapeutic approach for treating ccRCC. Development and validation of PI3K-Akt pathway-related genes related biomarkers can enhance healthcare management of patients with ccRCC.

PURPOSE

This study aimed to identify the key genes in the PI3K-Akt pathway associated with the diagnosis and prognosis of CCRCC using data mining from the Cancer Genome Atlas (TCGA) and Gene Expression Synthesis (GEO) datasets.

METHODS

The purpose of this study is to use bioinformatics methods to screen data sets and clinicopathological characteristics associated with ccRCC patients. The exhibited significantly differential expressed genes (DEGs) associated with the PI3K-Akt pathway were examined by KEGG. In addition, Kaplan-Meier (KM) analysis used to estimate the survival function of the differential genes by using the UALCAN database and graphPad Prism 9.0. And exploring the association between the expression levels of the selected genes and the survival status and time of patients with ccRCC based on SPSS22.0. Finally, a multigene prognostic model was constructed to assess the prognostic risk of ccRCC patients.

RESULTS

A total of 911 genes with common highly expressed were selected based on the GEO and TCGA databases. According to the KEGG pathway analysis, there were 42 genes enriched in PI3K-Akt signalling pathway. And seven of highly expressed genes were linked to a poor prognosis in ccRCC. And a multigene prognostic model was established based on IL2RG, EFNA3, and MTCP1 synergistic expression might be utilized to predict the survival of ccRCC patients.

CONCLUSIONS

Three PI3K-Akt pathway-related genes may be helpful to identify the prognosis and molecular characteristics of ccRCC patients and to improve therapeutic regimens, and these risk characteristics might be further applied in the clinic.

Metabolomics Reveals Tyrosine Kinase Inhibitor Resistance-Associated Metabolic Events in Human Metastatic Renal Cancer Cells

The development of resistance to tyrosine kinase inhibitors (TKIs) is a major cause of treatment failure in metastatic renal cell carcinoma (mRCC). A deeper understanding of the metabolic mechanisms associated with TKI resistance is critical for refining therapeutic strategies. In this study, we established resistance to sunitinib and pazopanib by exposing a parental Caki-1 cell line to increasing concentrations of sunitinib and pazopanib. The intracellular and extracellular metabolome of sunitinib- and pazopanib-resistant mRCC cells were investigated using a nuclear magnetic resonance (NMR)-based metabolomics approach. Data analysis included multivariate and univariate methods, as well as pathway and network analyses. Distinct metabolic signatures in sunitinib- and pazopanib-resistant RCC cells were found for the first time in this study. A common metabolic reprogramming pattern was observed in amino acid, glycerophospholipid, and nicotinate and nicotinamide metabolism. Sunitinib-resistant cells exhibited marked alterations in metabolites involved in antioxidant defence mechanisms, while pazopanib-resistant cells showed alterations in metabolites associated with energy pathways. Sunitinib-resistant RCC cells demonstrated an increased ability to proliferate, whereas pazopanib-resistant cells appeared to restructure their energy metabolism and undergo alterations in pathways associated with cell death. These findings provide potential targets for novel therapeutic strategies to overcome TKI resistance in mRCC through metabolic regulation.

Downregulation of UBB potentiates SP1/VEGFA-dependent angiogenesis in clear cell renal cell carcinoma

Clear cell renal cell carcinoma (ccRCC) presents a unique profile characterized by high levels of angiogenesis and robust vascularization. Understanding the underlying mechanisms driving this heterogeneity is essential for developing effective therapeutic strategies. This study revealed that ubiquitin B (UBB) is downregulated in ccRCC, which adversely affects the survival of ccRCC patients. UBB exerts regulatory control over vascular endothelial growth factor A (VEGFA) by directly interacting with specificity protein 1 (SP1), consequently exerting significant influence on angiogenic processes. Subsequently, we validated that DNA methyltransferase 3 alpha (DNMT3A) is located in the promoter of UBB to epigenetically inhibit UBB transcription. Additionally, we found that an unharmonious UBB/VEGFA ratio mediates pazopanib resistance in ccRCC. These findings underscore the critical involvement of UBB in antiangiogenic therapy and unveil a novel therapeutic strategy for ccRCC.

Molecular and functional characterization of reversible-sunitinib-tolerance state in human renal cell carcinoma

Therapy failure with the tyrosine kinase inhibitor (TKI) sunitinib remains a great challenge in metastatic renal cell carcinoma (mRCC). Growing evidence indicates that the tumour subpopulation can enter a transient, non-mutagenic drug-tolerant state to endure the treatment underlying the minimal residual disease and tumour relapse. Drug tolerance to sunitinib remains largely unexplored in RCC. Here, we show that sunitinib-tolerant 786-O/S and Caki-2/S cells are induced by prolonged drug treatment showing reduced drug sensitivity, enhanced clonogenicity, and DNA synthesis. Sunitinib-tolerance developed via dynamic processes, including (i) engagement of c-MET and AXL pathways, (ii) alteration of stress-induced p38 kinase and pro-survival BCL-2 signalling, (iii) extensive actin remodelling, which was correlated with activation of focal adhesion proteins. Remarkably, the acute drug response in both sensitive and sunitinib-tolerant cell lines led to dramatic fine-tuning of the actin-cytoskeleton and boosted cellular migration and invasion, indicating that the drug-response might depend on cell state transition rather than pre-existing mutations. The drug-tolerant state was transiently acquired, as the cells resumed initial drug sensitivity after >10 passages under drug withdrawal, reinforcing the concept of dynamic regulation and phenotypic heterogeneity. Our study described molecular events contributing to the reversible switch into sunitinib-tolerance, providing possible novel therapeutic opportunities in RCC.

Knockdown of Antisense Noncoding Mitochondrial RNA Reduces Tumorigenicity of Patient-Derived Clear Cell Renal Carcinoma Cells in an Orthotopic Xenograft Mouse Model

Clear cell renal cell carcinoma (ccRCC) is the most prevalent form of renal cancer and its treatment is hindered by a resistance to targeted therapies, immunotherapies and combinations of both. We have reported that the knockdown of the antisense noncoding mitochondrial RNAs (ASncmtRNAs) with chemically modified antisense oligonucleotides induces proliferative arrest and apoptotic death in tumor cells from many human and mouse cancer types. These studies have been mostly performed in vitro and in vivo on commercially available cancer cell lines and have shown that in mouse models tumor growth is stunted by the treatment. The present work was performed on cells derived from primary and metastatic ccRCC tumors. We established primary cultures from primary and metastatic ccRCC tumors, which were subjected to knockdown of ASncmtRNAs in vitro and in vivo in an orthotopic xenograft model in NOD/SCID mice. We found that these primary ccRCC cells are affected in the same way as tumor cell lines and in the orthotopic model tumor growth was significantly reduced by the treatment. This study on patient-derived ccRCC tumor cells represents a model closer to actual patient ccRCC tumors and shows that knockdown of ASncmtRNAs poses a potential treatment option for these patients.

[Peculiarities of angiogenesis in clear cell renal cancer]

A literature search was conducted to review papers on the results of studies of clear cell renal cancer (CCRC) vascularization. Numerous data on the relationship between tumor pathogenesis and its vascularization have been revealed, which indicates the multifactorial nature of CCRC development and the significant role of angiogenesis in this process. It should be taken into account that patients with CCRC may have impaired vessel formation even before tumor development. To evaluate normal and pathologic angiogenesis, a pathohistologic study using immunohistochemistry is certainly necessary. Due to the significant role of angiogenesis in the development and course of CCRC, the use of drugs that suppress the formation of the vascular network in the tumor is relevant and advisable. To date, many drugs have been developed and introduced into clinical practice to inhibit angiogenesis. However, such drugs have not lived up to the expectations placed due to the frequent and rapidly developing drug resistance. Timely detection of pre-tumor and tumor processes, as well as effective treatment of cancer, including CCRC, is possible only with close cooperation between pathomorphologists and oncologists.

Comparison of different estimated glomerular filtration rates for monitoring of kidney function in oncology patients

Background

Tyrosine kinase inhibitors (TKIs) are associated with kidney function deterioration. A shift is ongoing towards glomerular filtration rate (GFR) equations based on other protein markers, such as cystatin C (CSTC) and β-trace protein (BTP). We evaluated various GFR equations for monitoring of kidney function in actively treated oncology patients.

Methods

We monitored 110 patients receiving a TKI. Blood and urine were collected during therapy. Serum analysis included creatinine (Cr), CSTC and BTP; for consequent GFR determination. Urine was analysed for protein, albumin, immunoglobulin G, and α-1-microglobulin. A similar analysis was done in a patient subgroup receiving immune checkpoint inhibitors (ICI) as prior or subsequent line of therapy.

Results

Cr remained constant during TKI treatment (P = 0.7753), whereas a significant decrease in CSTC (from week 2 onward, P < 0.0001) and BTP (at weeks 2 and 4, P = 0.0100) were noticed. Consequently, GFR estimations, using CSTC and/or BTP as a biochemical parameter, showed an apparent increase in GFR, whereas this was not observed for Cr-related GFR estimations. As a result, the GFR gap (ΔGFR) was significantly different from week 2 onward between Cr-based and CSTC-based GFR and between BTP-based and CSTC-based GFR. Glomerular damage was noticed with significant increase in urine protein-to-creatinine ratio, albumin-to-creatinine ratio and immunoglobulin G (all P < 0.0001). No change in α-1-microglobulin was seen. ICI treatment had no effect on Cr (P = 0.2262), CSTC (P = 0.7341), and BTP concentrations (P = 0.3592).

Conclusion

GFR equations, in which CSTC is incorporated, fail to correctly estimate the GFR in oncology patients treated with TKIs. As TKI-treated patients show clear signs of glomerular injury, further assessment is needed on how to correctly monitor the kidney function in actively treated oncology patients.

Mechanisms of tyrosine kinase inhibitor resistance in renal cell carcinoma

Renal cell carcinoma (RCC), the most prevalent type of kidney cancer, is a significant cause of cancer morbidity and mortality worldwide. Antiangiogenic tyrosine kinase inhibitors (TKIs), in combination with immune checkpoint inhibitors (ICIs), are among the first-line treatment options for patients with advanced RCC. These therapies target the vascular endothelial growth factor receptor (VEGFR) tyrosine kinase pathway and other kinases crucial to cancer proliferation, survival, and metastasis. TKIs have yielded substantial improvements in progression-free survival (PFS) and overall survival (OS) for patients with advanced RCC. However, nearly all patients eventually progress on these drugs as resistance develops. This review provides an overview of TKI resistance in RCC and explores different mechanisms of resistance, including upregulation of alternative proangiogenic pathways, epithelial-mesenchymal transition (EMT), decreased intracellular drug concentrations due to efflux pumps and lysosomal sequestration, alterations in the tumor microenvironment including bone marrow-derived cells (BMDCs) and tumor-associated fibroblasts (TAFs), and genetic factors such as single nucleotide polymorphisms (SNPs). A comprehensive understanding of these mechanisms opens the door to the development of innovative therapeutic approaches that can effectively overcome TKI resistance, thereby improving outcomes for patients with advanced RCC.

Tyrosine Kinase Inhibitors for Renal Cell Carcinoma: A Bibliometric Analysis via CiteSpace from 2000 to 2022

BACKGROUND

The aim of the study was to identify the cooperation of authors, countries, institutions and explore the hot spots regarding research of tyrosine kinase inhibitors (TKIs) for renal cell carcinoma (RCC) treatment in the past 22 years.

SUMMARY

Relevant original and review articles were obtained from the Web of Science Core Collection from 2000 to 2022. CiteSpace software was used to perform the visualization of scientific productivity and emerging trends. Network maps were generated to evaluate the collaborations between different authors, countries, institutions, and keywords.

KEY MESSAGES

A total of 4,951 articles related to TKI for RCC treatment were identified. We observed a gradual increase in the number of publications from 2000 to 2022. The USA dominated the field in all countries, and Mem Sloan Kettering Cancer Centre (USA) had more extensive cooperating relationships with other institutions. Motzer RJ and Escudier B were two of the authority scholars in this specific field with the most publications and co-citations. Journal of Clinical Oncology had the most citations of all the journals. A total of 10 major clusters were explored based on the reference co-citation analysis. From 2000 to 2022, the research hot spots have undergone two dramatic shifts during 2006 and 2019, respectively, relevant topics were TKI and TKI combined with immune checkpoint inhibitors (CPIs). At present, the research hot spots focus on CPI and targeted therapies. Bibliometric analysis is allowing researchers to recognize the current research status by providing a comprehensive overview of the development of scientific literature related to TKI for RCC treatment, and information for further research be demonstrated as well.

Combination treatment with FAAH inhibitors/URB597 and ferroptosis inducers significantly decreases the growth and metastasis of renal cell carcinoma cells via the PI3K-AKT signaling pathway

Ferroptosis, a nonapoptotic form of programmed cell death characterized by significant iron-dependent peroxidation of phospholipids, is regulated by cellular metabolism, redox homeostasis, and various cancer-related signaling pathways. Recently, considerable progress has been made in demonstrating the critical role of lipid metabolism in regulating ferroptosis, indicating the potential of combinational strategies for treating cancer in the future. In this study, we explored the combinational effects of lipid metabolism compounds and ferroptosis inducers on renal cell carcinoma (RCC) cells. We found potent synergy of the fatty acid amide hydrolase (FAAH) inhibitor URB597 with ferroptosis inducer (1S, 3R)-RSL3 (RSL3) in inhibiting the growth and metastasis of RCC cells both in vitro and in vivo via induction of G1 cell cycle arrest and promotion of the production of lipid peroxides, malondialdehyde (MDA), 4-hydroxynonenal (4-HNE), and cytosolic reactive oxygen species (ROS). In addition, inhibition of FAAH increased the sensitivity of RCC cells to ferroptosis. Genome-wide RNA sequencing indicated that the combination of URB597 and RSL3 has more significant effects on regulation of the expression of genes related to cell proliferation, the cell cycle, cell migration and invasion, and ferroptosis than either single agent alone. Moreover, we found that combinational treatment modulated the sensitivity of RCC cells to ferroptosis via the phosphatidylinositol 3 kinase (PI3K)-AKT signaling pathway. These data demonstrate that dual targeting of FAAH and ferroptosis could be a promising strategy for treating RCC.

A novel endothelial-related prognostic index by integrating single-cell and bulk RNA sequencing data for patients with kidney renal clear cell carcinoma

Background: Endothelial cells in the tumor microenvironment play an important role in the development of kidney renal clear cell carcinoma (KIRC). We wanted to further identify the function of endothelial cells in KIRC patients by integrating single-cell and bulk RNA sequencing data.

Methods: Online databases provide the original data of this study. An endothelial-related prognostic index (ERPI) was constructed and validated by R version 3.6.3 and relative packages.

Results: The ERPI consisted of three genes (CCND1, MALL, and VWF). Patients with high ERPI scores were significantly correlated with worse prognosis than those with low ERPI scores in the TCGA training group, TCGA test group, and GSE29609 group. A positive correlation was identified between the ERPI score and poor clinical features. The results of functional analysis indicated that ERPI was significantly associated with immune-related activities. We suggested that patients with high ERPI scores were more likely to benefit from immunotherapy based on the results of immune checkpoints, tumor microenvironment, stemness index, and TCIA, while patients with low ERPI scores were sensitive to gemcitabine, docetaxel, paclitaxel, axitinib, pazopanib, sorafenib, and temsirolimus according to the results of the “pRRophetic” algorithm. Therefore, this ERPI may help doctors choose the optimal treatment for patients with KIRC.

Conclusion: By integrating single-cell and bulk RNA sequencing data from KIRC patients, we successfully identified the key genes from the perspective of endothelial cells in the tumor microenvironment and constructed ERPIs that had positive implications in precision medicine.

Tyrosine Kinase Inhibitors for Glioblastoma Multiforme: Challenges and Opportunities for Drug Delivery

Glioblastoma multiforme (GBM) is an aggressive brain tumor with high mortality rates. Due to its invasiveness, heterogeneity, and incomplete resection, the treatment is very challenging. Targeted therapies such as tyrosine kinase inhibitors (TKIs) have great potential for GBM treatment, however, their efficacy is primarily limited by poor brain distribution due to the presence of the blood-brain barrier (BBB). This review focuses on the potential of TKIs in GBM therapy and provides an insight into the reasons behind unsuccessful clinical trials of TKIs in GBM despite the success in treating other cancer types. The main section is dedicated to the use of promising drug delivery strategies for targeted delivery to brain tumors. Use of brain targeted delivery strategies can help enhance the efficacy of TKIs in GBM. Among various drug delivery approaches used to bypass or cross BBB, utilizing nanocarriers is a promising strategy to augment the pharmacokinetic properties of TKIs and overcome their limitations. This is because of their advantages such as the ability to cross BBB, chemical stabilization of drug in circulation, passive or active targeting of tumor, modulation of drug release from the carrier, and the possibility to be delivered via non-invasive intranasal route.