Efficacy of an EGFR-specific peptide against EGFR-dependent cancer cell lines and tumor xenografts

Design and investigation of novel iridoid-based peptide conjugates for targeting EGFR and its mutants L858R and T790M/L858R/C797S: an in silico study

In this work, we designed novel peptide conjugates with plant-based iridoid and lichen-derived depside derivatives to target the wild-type EGFR (WT) and its mutants, L858R and T790M/L858R/C797S triple mutant. These mutations are often expressed in multiple cancers, particularly lung cancer. Specifically, the iridoids included 7-deoxyloganetic acid (7-DGA) and loganic acid (LG), while the depside derivative was sekikaic acid (SK). These compounds are known for their innate anticancer properties and were conjugated with two separate peptide sequences KLPGWSG (K) and YSIPKSS (Y). These sequences have been shown to target EGFR in previous phage display library screening, although the mechanism is unknown. Thus, we created the di-conjugates for dual targeting and investigated their interactions of the di-conjugates and that of the neat peptides with the kinase domain of EGFR (WT) and the two mutants using molecular docking, molecular dynamics (MD) simulations, and MM-GBSA analysis. Docking studies revealed that the (7-DGA)2-K showed the highest binding affinity at - 9.3 kcal/mol with the L858R mutant, while (LG)2-Y displayed the highest binding affinity at - 9.0 kcal/mol for the triple mutant receptor. Our results indicated that several of the conjugates interacted with crucial residues of the kinase domain, including ASP855 and THR854 (activation loop), MET793 and PRO794 (hinge region), ARG841 (catalytic loop), and LYS728 and LEU718 of the glycine-rich P-loop. Interestingly, strong hydrophobic interactions were also observed with the C-terminal tail residues, such as PHE997 and ALA1000 as well as with ARG999 for the YSIPKSS peptide and most of the conjugates. The hydroxyl group of the cyclopentane ring and the oxygen of the pyran ring of the (7-DGA)2-peptide conjugates contributed to binding particularly in the hinge region, while the peptide components formed an extended structure that bound well into the C-lobe. The (SK)2-Y di-conjugate and KLPGWSG peptide formed hydrogen bonds with the SER797 residue of the triple mutant. Overall, our results show that the (7-DGA)2-K, di-conjugate, the (7-DGA)2-Y di-conjugate, and the neat YSIPKSS demonstrated strong and stable binding with the L858R mutant and the highly resistant triple mutant EGFR, respectively. The novel designed conjugates demonstrate potential for further optimization for laboratory studies aimed at developing new therapeutics for targeting specific EGFR mutant expressing cells.

Integrated meta-analysis and network pharmacology analysis: evaluation of Zhigancao decoction as treatment for diabetic cardiomyopathy

Background

Zhigancao Decoction (ZGCD) is derived from "Treatise on Febrile Diseases" and is traditionally prescribed for treating a variety of cardiovascular conditions. As of now, there are no data to support its use as a treatment for diabetic cardiomyopathy (DCM) and the mechanism behind the effect is unclear as well. In the present study, clinical evidence for the efficacy of ZGCD in patients with DCM was examined using a meta-analysis and its underlying anti-DCM molecular mechanisms were explored via network pharmacology.

Methods

The current study utilized an extensive search strategy encompassing various domestic and foreign databases databases to retrieve pertinent articles published up to June 2024. In light of this, a thorough evaluation of the benefits and safety of Zhigancao decoction (ZGCD) was conducted in this study using RevMan and Stata. Subsequently, a number of active compounds and target genes for ZGCD were gathered from the TCMSP and BATMAN-TCM databases, while the main targets for DCM were obtained from databases such as GenCards, OMIM, TTD, and DrugBank. To select core genes, protein-protein interaction networks were generated using the STRING platform, and enrichment analyses were completed using the Metascape platform.

Results

Meta-analysis results were ultimately derived from 9 studies involving 661 patients in total. In comparison with WM therapy alone, the pooled results showed that ZGCD significantly enhanced overall effectiveness. Additionally, the utilization of ZGCD was leading to a reduction in LVEDV, LVESV and LVDD, also a greater increase in LVEF. Meanwhile, the utilization of ZGCD during intervention was more effective in reducing SBP, and DBP. In addition, the ZGCD showed potential in reducing the occurrence of adverse events. In the context of network pharmacology, five constituents of ZGCD-namely lysine, quercetin, gamma-aminobutyric acid, stigmasterol, and beta-sitosterol-are posited to exert anti-diabetic cardiomyopathy (anti-DCM) effects through interactions with the molecular targets ASS1, SERPINE1, CACNA2D1, AVP, APOB, ICAM1, EGFR, TNNC1, F2, F10, IGF1, TNNI2, CAV1, INSR, and INS. The primary mechanisms by which ZGCD may achieve its anti-DCM effects are likely mediated via the AGEs/RAGE signaling pathway, as well as through pathways related to lipid metabolism and atherosclerosis.

Conclusion

In comparison to WM therapy alone, ZGCD demonstrates greater efficacy and safety in the management of DCM. ZGCD not only significantly reduces blood pressure, but also enhances cardiac function while producing fewer adverse effects. The therapeutic effects of ZGCD on DCM can likely be ascribed to its capacity to modulate the AGEs-RAGE signaling pathway, as well as its efficacy in enhancing lipid metabolism and mitigating atherosclerosis.

Systematic Review Registration

identifier (INPLASY202430133).

Anticancer Peptides Derived from Aldolase A and Induced Tumor-Suppressing Cells Inhibit Pancreatic Ductal Adenocarcinoma Cells

PDAC (pancreatic ductal adenocarcinoma) is a highly aggressive malignant tumor. We have previously developed induced tumor-suppressing cells (iTSCs) that secrete a group of tumor-suppressing proteins. Here, we examined a unique procedure to identify anticancer peptides (ACPs), using trypsin-digested iTSCs-derived protein fragments. Among the 10 ACP candidates, P04 (IGEHTPSALAIMENANVLAR) presented the most efficient anti-PDAC activities. P04 was derived from aldolase A (ALDOA), a glycolytic enzyme. Extracellular ALDOA, as well as P04, was predicted to interact with epidermal growth factor receptor (EGFR), and P04 downregulated oncoproteins such as Snail and Src. Importantly, P04 has no inhibitory effect on mesenchymal stem cells (MSCs). We also generated iTSCs by overexpressing ALDOA in MSCs and peripheral blood mononuclear cells (PBMCs). iTSC-derived conditioned medium (CM) inhibited the progression of PDAC cells as well as PDAC tissue fragments. The inhibitory effect of P04 was additive to that of CM and chemotherapeutic drugs such as 5-Flu and gemcitabine. Notably, applying mechanical vibration to PBMCs elevated ALDOA and converted PBMCs into iTSCs. Collectively, this study presented a unique procedure for selecting anticancer P04 from ALDOA in an iTSCs-derived proteome for the treatment of PDAC.

Current and emerging therapeutic approaches for colorectal cancer: A comprehensive review

Colorectal cancer (CRC) affects 1 in 23 males and 1 in 25 females, making it the third most common cancer. With roughly 608000 deaths worldwide, CRC accounts for 8% of all cancer-related deaths, making it the second most common cause of death due to cancer. Standard and conventional CRC treatments include surgical expurgation for resectable CRC and radiotherapy, chemotherapy, immunotherapy, and their combinational regimen for non-resectable CRC. Despite these tactics, nearly half of patients develop incurable recurring CRC. Cancer cells resist the effects of chemotherapeutic drugs in a variety of ways, including drug inactivation, drug influx and efflux modifications, and ATP-binding cassette transporter overexpression. These constraints necessitate the development of new target-specific therapeutic strategies. Emerging therapeutic approaches, such as targeted immune boosting therapies, non-coding RNA-based therapies, probiotics, natural products, oncolytic viral therapies, and biomarker-driven therapies, have shown promising results in preclinical and clinical studies. We tethered the entire evolutionary trends in the development of CRC treatments in this review and discussed the potential of new therapies and how they might be used in conjunction with conventional treatments as well as their advantages and drawbacks as future medicines.

Repurposing of FDA Approved Drugs and Neuropep peptides as Anticancer Agents Against ErbB1 and ErbB2

ErbB1 and ErbB2 are the most important biological targets in cancer drug discovery and development of dual inhibitors for the cancer therapy. FDA approved drugs and Neuropep peptides were used to fit into the ATP binding site of the tyrosine kinases; ErbB1 and ErbB2 proteins. Cytoscape, iGEMDOCK, HPEPDOCK and DataWarrior softwares were used to study the role of these agents as anticancer drugs. Eleven FDA approved drugs and eleven Neuropep peptides showed the strongest 2D interactions and significant binding energy with the proteins. Invitro MTT anticancer assay revealed that, the test compounds, peptide YSFGL and doxorubicin showed significant IC₅₀ value (µM) of 26.417±0.660 and 7.675±0.278 respectively which are compared with the lapatinib standard IC₅₀ value (µM) of 2.380±0.357 against A549 cells and IC₅₀ value (µM) of 39.047±0.770 and 8.313±0.435 respectively which are compared with the lapatinib standard IC₅₀ value (µM) of 3.026±0.180 against MDA-MB-231 cells.

Novel Cyclic Peptides for Targeting EGFR and EGRvIII Mutation for Drug Delivery

The epidermal growth factor-epidermal growth factor receptor (EGF-EGFR) pathway has become the main focus of selective chemotherapeutic intervention. As a result, two classes of EGFR inhibitors have been clinically approved, namely monoclonal antibodies and small molecule kinase inhibitors. Despite an initial good response rate to these drugs, most patients develop drug resistance. Therefore, new treatment approaches are needed. In this work, we aimed to find a new EGFR-specific, short cyclic peptide, which could be used for targeted drug delivery. Phage display peptide technology and biopanning were applied to three EGFR expressing cells, including cells expressing the EGFRvIII mutation. DNA from the internalized phage was extracted and the peptide inserts were sequenced using next-generation sequencing (NGS). Eleven peptides were selected for further investigation using binding, internalization, and competition assays, and the results were confirmed by confocal microscopy and peptide docking. Among these eleven peptides, seven showed specific and selective binding and internalization into EGFR positive (EGFR+ve) cells, with two of them-P6 and P9-also demonstrating high specificity for non-small cell lung cancer (NSCLC) and glioblastoma cells, respectively. These peptides were chemically conjugated to camptothecin (CPT). The conjugates were more cytotoxic to EGFR+ve cells than free CPT. Our results describe a novel cyclic peptide, which can be used for targeted drug delivery to cells overexpressing the EGFR and EGFRvIII mutation.

Personalized Immunotherapy in Colorectal Cancers: Where Do We Stand?

Colorectal cancer (CRC) is the second leading cause of cancer death in the world. Immunotherapy using monoclonal antibodies, immune-checkpoint inhibitors, adoptive cell therapy, and cancer vaccines has raised great hopes for treating poor prognosis metastatic CRCs that are resistant to the conventional therapies. However, high inter-tumor and intra-tumor heterogeneity hinder the success of immunotherapy in CRC. Patients with a similar tumor phenotype respond differently to the same immunotherapy regimen. Mutation-based classification, molecular subtyping, and immunoscoring of CRCs facilitated the multi-aspect grouping of CRC patients and improved immunotherapy. Personalized immunotherapy using tumor-specific neoantigens provides the opportunity to consider each patient as an independent group deserving of individualized immunotherapy. In the recent decade, the development of sequencing and multi-omics techniques has helped us classify patients more precisely. The expansion of such advanced techniques along with the neoantigen-based immunotherapy could herald a new era in treating heterogeneous tumors such as CRC. In this review article, we provided the latest findings in immunotherapy of CRC. We elaborated on the heterogeneity of CRC patients as a bottleneck of CRC immunotherapy and reviewed the latest advances in personalized immunotherapy to overcome CRC heterogeneity.

Peptide-Based Drug Delivery Systems

Peptide-based drug delivery systems have many advantages when compared to synthetic systems in that they have better biocompatibility, biochemical and biophysical properties, lack of toxicity, controlled molecular weight via solid phase synthesis and purification. Lysosomes, solid lipid nanoparticles, dendrimers, polymeric micelles can be applied by intravenous administration, however they are of artificial nature and thus may induce side effects and possess lack of ability to penetrate the blood-brain barrier. An analysis of nontoxic drug delivery systems and an establishment of prospective trends in the development of drug delivery systems was needed. This review paper summarizes data, mainly from the past 5 years, devoted to the use of peptide-based carriers for delivery of various toxic drugs, mostly anticancer or drugs with limiting bioavailability. Peptide-based drug delivery platforms are utilized as peptide–drug conjugates, injectable biodegradable particles and depots for delivering small molecule pharmaceutical substances (500 Da) and therapeutic proteins. Controlled drug delivery systems that can effectively deliver anticancer and peptide-based drugs leading to accelerated recovery without significant side effects are discussed. Moreover, cell penetrating peptides and their molecular mechanisms as targeting peptides, as well as stimuli responsive (enzyme-responsive and pH-responsive) peptides and peptide-based self-assembly scaffolds are also reviewed.

A novel cyclic NP1 reveals obstruction of EGFR kinase activity and attenuation of EGFR-driven cell lines

Aberrations of the epidermal growth factor receptor (EGFR), for example, mutations and overexpression, play pivotal roles in various cellular functions, such as proliferation, migration, and cell differentiation. Approved small molecule-based inhibitors, including gefitinib and erlotinib, are used clinically to target the tyrosine kinase domain of EGFR (TK-EGFR). However, the severity of the side effects, off-target effects, and drug resistance is a concern. Cyclic peptides are a well-known peptide format with high stability and are promising molecules for drug development. Herein, the Ph.D.™-C7C phage display library was used to screen cyclic peptides against TK-EGFR. Biopanning, both with and without propagation methods, was performed to assess the highest capacity peptides using the enzymatic activity of TK-EGFR. Interestingly, NP1, a peptide selected during biopanning without propagation demonstrated an inhibitory effect against TK-EGFR at IC₅₀ within the nanomolar range; this effect was better than that of P1 obtained using biopanning with propagation. Moreover, NP1 elicited EGFR with an affinity binding (K_D ) value of 18.40 ± 5.50 µM by surface plasmon resonance (SPR). Introducing cell-penetrating peptides or Arginine-9 (Arg9) at the N-terminus of NP1 thus improves cell-penetrability and can lead to the inhibition of EGFR-driven cancer cell lines; however, it exhibits no hepatotoxicity. Furthermore, NP1 caused a decrease in phosphorylated EGFR after activation within cells. A docking model shows that NP1 interacted primarily with TK-EGFR via hydrogen bonding. Together, this suggests that NP1 is a novel EGFR peptide inhibitor candidate with specificity and selectivity toward TK-EGFR, and may be applied to targeted therapy.

Disruptin, a cell-penetrating peptide degrader of EGFR: Cell-Penetrating Peptide in Cancer Therapy

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Systemic injection of Disruptin is effective in small tumors but was minimally effective in animals with established tumors.

Intratumoral injections of Disruptin reduced EGFR protein level and slowed tumor growth.

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Disruptin peptide causes the disappearance of EGFR protein and also affect angiogenesis.

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The Disruptin peptide was toxic when dosed systemically.

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Overall, these findings suggest that an agent that can reduce EGFR protein could offer an alternate therapy for EGFR driven tumors.

Disruptin is a cell-permeable decoy peptide designed to destabilize activated EGFR, both by inhibiting Hsp90 chaperoning and dissociating the active asymmetric EGFR dimer, which leads to an increase in engagement of activated EGFR with the proteolytic degradation machinery and subsequent loss from the cells. Disruptin is an N-terminally biotinylated nonadecapeptide, with 8 amino acids from the αC-helix-β4 sheet loop of EGFR (S⁷⁶⁷-C⁷⁷⁴) fused to a TAT undecapeptide. The S⁷⁶⁷-R⁷⁷⁵ loop is at the interface with juxtamembrane domains in the active EGFR dimers and is a binding site for Hsp90. Cellular studies in EGFR-activated tumor cells demonstrated that Disruptin causes the disappearance of EGFR protein from cells over a few hours, a growth inhibitory effect, similar but more effective than the EGFR kinase inhibition. Interestingly, cells without activated EGFR remained unaffected. In vivo studies showed that Disruptin slowed the growth of small tumors. Larger tumors responded to intratumoral injections but did not respond to systemic administration at tolerated doses. Investigation of these results revealed that systemic administration of Disruptin has acute toxicities, mainly related to its TAT peptide moiety. Therefore, we conclude that although the efficacy of both in vitro and in vivo intratumoral injection of Disruptin supports the therapeutic strategy of blocking activated EGFR dimerization, Disruptin is not suitable for further development. These studies also highlight the importance of the chosen models and drug-delivery methods for such investigations.

Peptides-based therapy and diagnosis. Strategies for non-invasive therapies in cancer

In recent years, remarkable progress was registered in the field of cancer research. Though, cancer still represents a major cause of death and cancer metastasis a problem seeking for urgent solutions as it is the main reason for therapeutic failure. Unfortunately, the most common chemotherapeutic agents are non-selective and can damage healthy tissues and cause side effects that affect dramatically the quality of life of the patients. Targeted therapy with molecules that act specifically at the tumour sites interacting with overexpressed cancer receptors is a very promising strategy for achieving the specific delivery of anticancer drugs, radioisotopes or imaging agents. This review aims to give an overview on different strategies for targeting cancer cell receptors localised either at the extracellular matrix or at the cell membrane. Molecules like antibodies, aptamers and peptides targeting the cell surface are presented with advantages and disadvantages, with emphasis on peptides. The most representative peptides are described, including cell penetrating peptides, homing and anticancer peptides with particular consideration on recent discoveries.

Homing Peptides for Cancer Therapy

Tumor-homing peptides are widely used for improving tumor selectivity of anticancer drugs and imaging agents. The goal is to increase tumor uptake and reduce accumulation at nontarget sites. Here, we describe current approaches for tumor-homing peptide identification and validation, and provide comprehensive overview of classes of tumor-homing peptides undergoing preclinical and clinical development. We focus on unique mechanistic features and applications of a recently discovered class of tumor-homing peptides, tumor-penetrating C-end Rule (CendR) peptides, that can be used for tissue penetrative targeting of extravascular tumor tissue. Finally, we discuss unanswered questions and future directions in the field of development of peptide-guided smart drugs and imaging agents.

Therapeutic vaccines for colorectal cancer: The progress and future prospect

Cancer vaccines are usually derived from the patient's tumor cells or the antigens found on their surface, which may help the immune system to identify and kill these malignant cells. Current focus of many researches is designing vaccines with the hope of triggering the immune system to attack cancer cells in a more effective, reliable and safe manner. Although colorectal cancer (CRC) is recognized as the third leading cause of death by cancer, but significant advances in therapy strategies have been made in recent years, including cancer vaccine. In this review, we present various vaccine platforms that have been used in the border battle against CRC, some of which have been approved for clinical use and some are in late-stage clinical trials. Until September 2020 there is approximately 1940 clinical trials of cancer vaccines on patients with different cancer types, and also many more trials are in the planning stages, which makes it the most important period of therapeutic cancer vaccines studies in the history of the immunotherapy. In cancer vaccines clinical trials, there are several considerations that must be taken into account including engineering of antigen-presenting cells, potential toxicity of antigenic areas, pharmacokinetics and pharmacodynamics of vaccines, and monitoring of the patients' immune response. Therefore, the need to overcome immunosuppression mechanisms/immune tolerance is a critical step for the success of introducing therapeutic vaccines into the widely used drugs on market. In this way, better understanding of neoantigens, tumor immune surveillance escape mechanisms and host-tumor interactions are required to develop more effective and safe cancer vaccines.

Targeting and therapeutic peptide-based strategies for polycystic kidney disease

Polycystic kidney disease (PKD) is characterized by progressive cyst growth and is a leading cause of renal failure worldwide. Currently, there are limited therapeutic options available to PKD patients, and only one drug, tolvaptan, has been FDA-approved to slow cyst progression. Similar to other small molecule drugs, however, tolvaptan is costly, only moderately effective, and causes adverse events leading to high patient dropout rates. Peptides may mitigate many drawbacks of small molecule drugs, as they can be highly tissue-specific, biocompatible, and economically scaled-up. Peptides can function as targeting ligands that direct therapies to diseased renal tissue, or be potent as therapeutic agents themselves. This review discusses various aberrant signaling pathways in PKD and renal receptors that can be potential targets of peptide-mediated strategies. Additionally, peptides utilized in other kidney applications, but may prove useful in the context of PKD, are highlighted. Insights into novel peptide-based solutions that have potential to improve clinical management of PKD are provided.

Peptide-based materials for cancer immunotherapy

Peptide-based materials hold great promise as immunotherapeutic agents for the treatment of many malignant cancers. Extensive studies have focused on the development of peptide-based cancer vaccines and delivery systems by mimicking the functional domains of proteins with highly specific immuno-regulatory functions or tumor cells fate controls. However, a systemic understanding of the interactions between the different peptides and immune systems remains unknown. This review describes the role of peptides in regulating the functions of the innate and adaptive immune systems and provides a comprehensive focus on the design, categories, and applications of peptide-based cancer vaccines. By elucidating the impacts of peptide length and formulations on their immunogenicity, peptide-based immunomodulating agents can be better utilized and dramatic breakthroughs may also be realized. Moreover, some critical challenges for translating peptides into large-scale synthesis, safe delivery, and efficient cancer immunotherapy are posed to improve the next-generation peptide-based immunotherapy.

Understanding Cell Penetration of Cyclic Peptides

Approximately 75% of all disease-relevant human proteins, including those involved in intracellular protein-protein interactions (PPIs), are undruggable with the current drug modalities (i.e., small molecules and biologics). Macrocyclic peptides provide a potential solution to these undruggable targets because their larger sizes (relative to conventional small molecules) endow them the capability of binding to flat PPI interfaces with antibody-like affinity and specificity. Powerful combinatorial library technologies have been developed to routinely identify cyclic peptides as potent, specific inhibitors against proteins including PPI targets. However, with the exception of a very small set of sequences, the vast majority of cyclic peptides are impermeable to the cell membrane, preventing their application against intracellular targets. This Review examines common structural features that render most cyclic peptides membrane impermeable, as well as the unique features that allow the minority of sequences to enter the cell interior by passive diffusion, endocytosis/endosomal escape, or other mechanisms. We also present the current state of knowledge about the molecular mechanisms of cell penetration, the various strategies for designing cell-permeable, biologically active cyclic peptides against intracellular targets, and the assay methods available to quantify their cell-permeability.

Armored long non-coding RNA MEG3 targeting EGFR based on recombinant MS2 bacteriophage virus-like particles against hepatocellular carcinoma

Hepatocellular carcinoma (HCC) is one of the most frequently diagnosed cancers worldwide. However, the treatment of patients with HCC is particularly challenging. Long non-coding RNA maternally expressed gene 3 (MEG3) has been identified as a potential suppressor of several types of tumors, but the delivery of long RNA remains problematic, limiting its applications. In the present study, we designed a novel delivery system based on MS2 virus-like particles (VLPs) crosslinked with GE11 polypeptide. This vector was found to be fast, effective and safe for the targeted delivery of lncRNA MEG3 RNA to the epidermal growth factor receptor (EGFR)-positive HCC cell lines without the activation of EGFR downstream pathways, and significantly attenuated both in vitro and in vivo tumor cell growth. Our study also revealed that the targeted delivery was mainly dependent on clathrin-mediated endocytosis and MEG3 RNA suppresses tumor growth mainly via increasing the expression of p53 and its downstream gene GDF15, but decreasing the expression of MDM2. Thus, this vector is promising as a novel delivery system and may facilitate a new approach to lncRNA based cancer therapy.

Differential protein stability of EGFR mutants determines responsiveness to tyrosine kinase inhibitors

Non-small cell lung cancer (NSCLC) patients carrying specific EGFR kinase activating mutations (L858R, delE746-A750) respond well to tyrosine kinase inhibitors (TKIs). However, drug resistance develops within a year. In about 50% of such patients, acquired drug resistance is attributed to the enrichment of a constitutively active point mutation within the EGFR kinase domain (T790M). To date, differential drug-binding and altered ATP affinities by EGFR mutants have been shown to be responsible for differential TKI response. As it has been reported that EGFR stability plays a role in the survival of EGFR driven cancers, we hypothesized that differential TKI-induced receptor degradation between the sensitive L858R and delE746-A750 and the resistant T790M may also play a role in drug responsiveness. To explore this, we have utilized an EGFR-null CHO overexpression system as well as NSCLC cell lines expressing various EGFR mutants and determined the effects of erlotinib treatment. We found that erlotinib inhibits EGFR phosphorylation in both TKI sensitive and resistant cells, but the protein half-lives of L858R and delE746-A750 were significantly shorter than L858R/T790M. Third generation EGFR kinase inhibitor (AZD9291) inhibits the growth of L858R/T790M-EGFR driven cells and also induces EGFR degradation. Erlotinib treatment induced polyubiquitination and proteasomal degradation, primarily in a c-CBL-independent manner, in TKI sensitive L858R and delE746-A750 mutants when compared to the L858R/T790M mutant, which correlated with drug sensitivity. These data suggest an additional mechanism of TKI resistance, and we postulate that agents that degrade L858R/T790M-EGFR protein may overcome TKI resistance.

Updates on immunotherapy for colorectal cancer

Despite significant advances in standard of care therapies, the 5-year survival rate for metastatic colorectal cancer (CRC) remains around 12%. Immunotherapy has not provided the stellar advances in colorectal cancer that has been seen in other malignancies. Immunotherapy appears to play a pivotal role in microsatellite unstable CRC tumors where the response rates are profound. These results have led to FDA approval of pembrolizumab for MSI-H CRC tumors. Additional research into several new immune agents including IDO inhibitors, vaccine therapy and combinatorial agents are being evaluated for CRC. This review will provide an overview of the approaches currently being investigated.

Inducing Oncoprotein Degradation to Improve Targeted Cancer Therapy

Over the past decade, inhibition of the kinase activities of oncogenic proteins using small molecules and antibodies has been a mainstay of our anticancer drug development effort, resulting in several Food and Drug Administration–approved cancer therapies. The clinical effectiveness of kinase-targeted agents has been inconsistent, mostly because of the development of resistance. The expression and function of oncoproteins and tumor suppressors are regulated by numerous posttranslational protein modifications including phosphorylation, ubiquitination, and acetylation; hence, targeting specific posttranslational protein modifications provides for an attractive strategy for anticancer drug development. The present review discusses the hypothesis that targeted degradation of an oncoprotein may overcome many of the shortcomings seen with kinase inhibitors and that the approach would enable targeted inhibition of oncogenic proteins previously thought to be undruggable.

Extracellular heat shock protein 90 binding to TGFβ receptor I participates in TGFβ-mediated collagen production in myocardial fibroblasts

The pathological remodeling heart shows an increase in left ventricular mass and an excess of extracellular matrix deposition that can over time cause heart failure. Transforming growth factor β (TGFβ) is the main cytokine controlling this process. The molecular chaperone heat shock protein 90 (Hsp90) has been shown to play a critical role in TGFβ signaling by stabilizing the TGFβ signaling cascade. We detected extracellular Hsp90 in complex with TGFβ receptor I (TGFβRI) in fibroblasts and determined a close proximity between both proteins suggesting a potential physical interaction between the two at the plasma membrane. This was supported by in silico studies predicting Hsp90 dimers and TGFβRI extracellular domain interaction. Both, Hsp90aa1 and Hsp90ab1 isoforms participate in TGFβRI complex. Extracellular Hsp90 inhibition lessened the yield of collagen production as well as the canonical TGFβ signaling cascade, and collagen protein synthesis was drastically reduced in Hsp90aa1 KO mice. These observations together with the significant increase in activity of Hsp90 at the plasma membrane pointed to a functional cooperative partnership between Hsp90 and TGFβRI in the fibrotic process. We propose that a surface population of Hsp90 extracellularly binds TGFβRI and this complex behaves as an active participant in collagen production in TGFβ-activated fibroblasts. We also offer an in vivo insight into the role of Hsp90 and its isoforms during cardiac remodeling in murine aortic banding model suffering from pathological cardiac remodeling and detect circulating Hsp90 overexpressed in remodeling mice.

AZD9291 overcomes T790 M-mediated resistance through degradation of EGFR(L858R/T790M) in non-small cell lung cancer cells

The discovery of activating mutations of epidermal growth factor receptor (EGFR) has resulted in the development of more effective treatments for non-small cell lung cancer (NSCLC). Although first-generation EGFR tyrosine kinase inhibitors (EGFR TKIs) provide significant clinical benefit, acquired resistance often occurs, most commonly (>50 %) via a T790 M resistance mutation. Although AZD9291 is selective for both T790 M and activating EGFR mutations over wild-type EGFR, it is highly active when T790 M is present, especially EGFR(L858R/T790M), and modestly active when T790 M is absent. The aim of this study was to elucidate the underlying mechanism of the high sensitivity of NSCLC cells harboring EGFR(L858R/T790M) to AZD9291. In H1975 cells harboring EGFR(L858R/T790M), AZD9291 potently inhibited cellular growth and EGFR signaling pathways together with depletion of mutant EGFR protein. AZD9291-induced depletion of EGFR(L858R/T790M) protein was abrogated through inhibition of the proteasome with MG132. However, AZD9291 had no effect on protein levels of EGFR(WT) and EGFR(L858R). In addition, AZD9291 induced apoptosis and caused expression changes in cell cycle-related genes. Moreover, oral administration of AZD9291 as a single agent induced tumor regression in vivo in a H1975 tumor xenograft model and reduced EGFR(L858R/T790M) protein levels in xenograft tumors. Taken together, our results provide a potential mechanism for the sensitivity of EGFR(L858R/T790M) cells to AZD9291 and suggest that AZD9291 may be effective in cases of T790 M-positive EGFR resistance.

Peptide-Based Treatment: A Promising Cancer Therapy

Many new therapies are currently being used to treat cancer. Among these new methods, chemotherapy based on peptides has been of great interest due to the unique advantages of peptides, such as a low molecular weight, the ability to specifically target tumor cells, and low toxicity in normal tissues. In treating cancer, peptide-based chemotherapy can be mainly divided into three types, peptide-alone therapy, peptide vaccines, and peptide-conjugated nanomaterials. Peptide-alone therapy may specifically enhance the immune system's response to kill tumor cells. Peptide-based vaccines have been used in advanced cancers to improve patients' overall survival. Additionally, the combination of peptides with nanomaterials expands the therapeutic ability of peptides to treat cancer by enhancing drug delivery and sensitivity. In this review, we mainly focus on the new advances in the application of peptides in treating cancer in recent years, including diagnosis, treatment, and prognosis.

EGFR targeted therapies and radiation: Optimizing efficacy by appropriate drug scheduling and patient selection

The epidermal growth factor receptor (EGFR) plays an important role in tumor progression and treatment resistance for many types of malignancies including head and neck, colorectal, and nonsmall cell lung cancer. Several EGFR targeted therapies are efficacious as single agents or in combination with chemotherapy. Given the toxicity associated with chemoradiation and poor outcomes seen in several types of cancers, combinations of EGFR targeted agents with or without chemotherapy have been tested in patients receiving radiation. To date, the only FDA approved use of an anti-EGFR therapy in combination with radiation therapy is for locally advanced head and neck cancer. Given the important role EGFR plays in lung and colorectal cancer and the benefit of EGFR inhibition combined with chemotherapy in these disease sites, it is perplexing why EGFR targeted therapies in combination with radiation or chemoradiation have not been more successful. In this review we summarize the clinical findings of EGFR targeted therapies combined with radiation and chemoradiation regimens. We then discuss the interaction between EGFR and radiation including radiation induced EGFR signaling, the effect of EGFR on DNA damage repair, and potential mechanisms of radiosensitization. Finally, we examine the potential pitfalls with scheduling EGFR targeted therapies with chemoradiation and the use of predictive biomarkers to improve patient selection.

[Application of target peptide in siRNA delivery for the research of lung cancer therapy]

肺癌被认为是全球发病率最高的一种恶性肿瘤，其对化疗药物不敏感且易产生耐药性，因此增强肺癌药物治疗效果是近年来研究的热点。siRNA是一种小RNA分子，可以沉默与之互补的目标mRNA，是一种基因治疗手段。靶向肽是一类小分子多肽，它可以与siRNA联合使用，利用其与肿瘤表面物质特异性结合发挥靶向作用。联合靶向肽的特异性和siRNA的治疗作用，增加siRNA在靶点位置的聚集，增强沉默效果，可以提高肺癌对药物的敏感性并降低耐药作用，进而增强肺癌治疗效果，为肺癌的靶向治疗提供新的方向和策略。本文将对靶向肽在递送siRNA进行肺癌治疗研究中的应用作一简要综述。