Combination of cationic dexamethasone derivative and STAT3 inhibitor (WP1066) for aggressive melanoma: a strategy for repurposing a phase I clinical trial drug

Inhibition of JAK/STAT3 Expression by Acute Myeloid Leukemia-Targeted Nanoliposome for Chemotherapy Enhancement

Acute myeloid leukemia (AML) is a relatively common malignant hematological disease whose development is mostly associated with abnormal activation of the JAK/STAT3 signaling pathway. Our previous study revealed that SAR317461, a novel JAK2/STAT3 inhibitor, can effectively inhibit the activation of the JAK2/STAT3 signaling pathway and has significant damaging and pro-apoptotic effects on AML cell lines. This project aims to build upon our prior research to enhance the application of SAR317461 in AML. The surface modification of liposomes with the CD34 antibody, along with the inclusion of the SAR317461 and cytarabine (a common AML chemotherapeutic agent), is observed. Due to the high expression of CD34 on the surface of AML cells, the nanoliposome could target AML cells specifically, further achieving an effective treatment for AML through the synergistic effect of JAK2/STAT3 inhibitors and chemotherapeutic agents. The implementation of this project will provide more theoretical support and ideas for the clinical application of JAK/STAT3 inhibitors in malignant tumors and for overcoming chemotherapy resistance.

Exploring Novel Frontiers: Leveraging STAT3 Signaling for Advanced Cancer Therapeutics

Signal Transducer and Activator of Transcription 3 (STAT3) plays a significant role in diverse physiologic processes, including cell proliferation, differentiation, angiogenesis, and survival. STAT3 activation via phosphorylation of tyrosine and serine residues is a complex and tightly regulated process initiated by upstream signaling pathways with ligand binding to receptor and non-receptor-linked kinases. Through downstream deregulation of target genes, aberrations in STAT3 activation are implicated in tumorigenesis, metastasis, and recurrence in multiple cancers. While there have been extensive efforts to develop direct and indirect STAT3 inhibitors using novel drugs as a therapeutic strategy, direct clinical application remains in evolution. In this review, we outline the mechanisms of STAT3 activation, the resulting downstream effects in physiologic and malignant settings, and therapeutic strategies for targeting STAT3. We also summarize the pre-clinical and clinical evidence of novel drug therapies targeting STAT3 and discuss the challenges of establishing their therapeutic efficacy in the current clinical landscape.

Targeting the STAT3 oncogenic pathway: Cancer immunotherapy and drug repurposing

Immune effector cells in the microenvironment tend to be depleted or remodeled, unable to perform normal functions, and even promote the malignant characterization of tumors, resulting in the formation of immunosuppressive microenvironments. The strategy of reversing immunosuppressive microenvironment has been widely used to enhance the tumor immunotherapy effect. Signal transducer and activator of transcription 3 (STAT3) was found to be a crucial regulator of immunosuppressive microenvironment formation and activation as well as a factor, stimulating tumor cell proliferation, survival, invasiveness and metastasis. Therefore, regulating the immune microenvironment by targeting the STAT3 oncogenic pathway might be a new cancer therapy strategy. This review discusses the pleiotropic effects of STAT3 on immune cell populations that are critical for tumorigenesis, and introduces the novel strategies targeting STAT3 oncogenic pathway for cancer immunotherapy. Lastly, we summarize the conventional drugs used in new STAT3-targeting anti-tumor applications.

Therapeutic targeting of anoikis resistance in cutaneous melanoma metastasis

The acquisition of resistance to anoikis, the cell death induced by loss of adhesion to the extracellular matrix, is an absolute requirement for the survival of disseminating and circulating tumour cells (CTCs), and for the seeding of metastatic lesions. In melanoma, a range of intracellular signalling cascades have been identified as potential drivers of anoikis resistance, however a full understanding of the process is yet to be attained. Mechanisms of anoikis resistance pose an attractive target for the therapeutic treatment of disseminating and circulating melanoma cells. This review explores the range of small molecule, peptide and antibody inhibitors targeting molecules involved in anoikis resistance in melanoma, and may be repurposed to prevent metastatic melanoma prior to its initiation, potentially improving the prognosis for patients.

Synthesis and evaluation of naphthalene derivatives as potent STAT3 inhibitors and agents against triple-negative breast cancer growth and metastasis

PURPOSE

Triple-negative breast cancer (TNBC) represents the worst prognostic subtype of breast cancer and lacks targeted therapeutic drugs. Signal transducer and activator of transcription 3 (STAT3) is overexpressed and constitutively activated in TNBCs and associated with poor patient outcomes. However, no agents targeting STAT3 have been successfully developed and marketed. Selective Estrogen Receptor Modulators (SERMs) have been reported as potential inhibitors of the IL-6/STAT3 signaling pathway. Naphthalene compounds have good pharmacological activity and significant anti-cancer activity. In this study, we synthesized a new series of naphthalene derivatives with the general structure of SERM and evaluated their effects on TNBC and STAT3 signals.

METHODS

A new series of compounds based on the scaffold of SERMs and an amino group were designed and screened based on the structure-activity relationship by MTT assay. The binding activity of SMY002 to STAT3 was predicted and validated by docking and SPR. The STAT3 signaling target and anti-cancer effects of SMY002 were evaluated with three TNBC cell lines and the mice transplanted tumor model.

RESULTS

Among the compounds, SMY002 displayed the most potent activity, which could directly interact with STAT3 SH2-domain, and strongly inhibit the phosphorylation, dimerization, nuclear distribution, transcriptional activity, and target genes expression of STAT3. Furthermore, SMY002 markedly suppressed migration, invasion, survival, growth, and metastasis of TNBC cells in vitro and in vivo via down-regulating the expression of Cyclin D1 and MMP9.

CONCLUSIONS

SMY002 can significantly inhibit the growth and metastasis of TNBC cells by targeting the STAT3 signal.

Drug repurposing: An emerging strategy in alleviating skin cancer

Skin cancer is one of the most common forms of cancer. Several million people are estimated to have affected with this condition worldwide. Skin cancer generally includes melanoma and non-melanoma with the former being the most dangerous. Chemotherapy has been one of the key therapeutic strategies employed in the treatment of skin cancer, especially in advanced stages of the disease. It could be also used as an adjuvant with other treatment modalities depending on the type of skin cancer. However, there are several shortfalls associated with the use of chemotherapy such as non-selectivity, tumour resistance, life-threatening toxicities, and the exorbitant cost of medicines. Furthermore, new drug discovery is a lengthy and costly process with minimal likelihood of success. Thus, drug repurposing (DR) has emerged as a new avenue where the drug approved formerly for the treatment of one disease can be used for the treatment of another disease like cancer. This approach is greatly beneficial over the de novo approach in terms of time and cost. Moreover, there is minimal risk of failure of repurposed therapeutics in clinical trials. There are a considerable number of studies that have reported on drugs repurposed for the treatment of skin cancer. Thus, the present manuscript offers a comprehensive overview of drugs that have been investigated as repurposing candidates for the efficient treatment of skin cancers mainly melanoma and its oncogenic subtypes, and non-melanoma. The prospects of repurposing phytochemicals against skin cancer are also discussed. Furthermore, repurposed drug delivery via topical route and repurposed drugs in clinical trials are briefed. Based on the findings from the reported studies discussed in this manuscript, drug repurposing emerges to be a promising approach and thus is expected to offer efficient treatment at a reasonable cost in devitalizing skin cancer.

STAT3 pathway in cancers: Past, present, and future

Signal transducer and activator of transcription 3 (STAT3), a member of the STAT family, discovered in the cytoplasm of almost all types of mammalian cells, plays a significant role in biological functions. The duration of STAT3 activation in normal tissues is a transient event and is strictly regulated. However, in cancer tissues, STAT3 is activated in an aberrant manner and is induced by certain cytokines. The continuous activation of STAT3 regulates the expression of downstream proteins associated with the formation, progression, and metastasis of cancers. Thus, elucidating the mechanisms of STAT3 regulation and designing inhibitors targeting the STAT3 pathway are considered promising strategies for cancer treatment. This review aims to introduce the history, research advances, and prospects concerning the STAT3 pathway in cancer. We review the mechanisms of STAT3 pathway regulation and the consequent cancer hallmarks associated with tumor biology that are induced by the STAT3 pathway. Moreover, we summarize the emerging development of inhibitors that target the STAT3 pathway and novel drug delivery systems for delivering these inhibitors. The barriers against targeting the STAT3 pathway, the focus of future research on promising targets in the STAT3 pathway, and our perspective on the overall utility of STAT3 pathway inhibitors in cancer treatment are also discussed.

Targeting Treg-Expressed STAT3 Enhances NK-Mediated Surveillance of Metastasis and Improves Therapeutic Response in Pancreatic Adenocarcinoma

PURPOSE

Metastasis remains a major hurdle in treating aggressive malignancies such as pancreatic ductal adenocarcinoma (PDAC). Improving response to treatment, therefore, requires a more detailed characterization of the cellular populations involved in controlling metastatic burden.

EXPERIMENTAL DESIGN

PDAC patient tissue samples were subjected to RNA sequencing analysis to identify changes in immune infiltration following radiotherapy. Genetically engineered mouse strains in combination with orthotopic tumor models of PDAC were used to characterize disease progression. Flow cytometry was used to analyze tumor infiltrating, circulating, and nodal immune populations.

RESULTS

We demonstrate that although radiotherapy increases the infiltration and activation of dendritic cells (DC), it also increases the infiltration of regulatory T cells (Treg) while failing to recruit natural killer (NK) and CD8 T cells in PDAC patient tissue samples. In murine orthotopic tumor models, we show that genetic and pharmacologic depletion of Tregs and NK cells enhances and attenuates response to radiotherapy, respectively. We further demonstrate that targeted inhibition of STAT3 on Tregs results in improved control of local and distant disease progression and enhanced NK-mediated immunosurveillance of metastasis. Moreover, combination treatment of STAT3 antisense oligonucleotide (ASO) and radiotherapy invigorated systemic immune activation and conferred a survival advantage in orthotopic and metastatic tumor models. Finally, we show the response to STAT3 ASO + radiotherapy treatment is dependent on NK and DC subsets.

CONCLUSIONS

Our results suggest targeting Treg-mediated immunosuppression is a critical step in mediating a response to treatment, and identifying NK cells as not only a prognostic marker of improved survival, but also as an effector population that functions to combat metastasis.

Advantages and drawbacks of dexamethasone in glioblastoma multiforme

The most widespread, malignant, and deadliest type of glial tumor is glioblastoma multiforme (GBM). Despite radiation, chemotherapy, and radical surgery, the median survival of afflicted individuals is about 12 months. Unfortunately, existing therapeutic interventions are abysmal. Dexamethasone (Dex), a synthetic glucocorticoid, has been used for many years to treat brain edema and inflammation caused by GBM. Several investigations have recently shown that Dex also exerts antitumoral effects against GBM. On the other hand, more recent disputed findings have questioned the long-held dogma of Dex treatment for GBM. Unfortunately, steroids are associated with various undesirable side effects, including severe immunosuppression and metabolic changes like hyperglycemia, which may impair the survival of GBM patients. Current ideas and concerns about Dex's effects on GBM cerebral edema, cell proliferation, migration, and its clinical outcomes were investigated in this study.

Targeting steroid hormone receptors for anti-cancer therapy-A review on small molecules and nanotherapeutic approaches

The steroid hormone receptors (SHRs) among nuclear hormone receptors (NHRs) are steroid ligand-dependent transcription factors that play important roles in the regulation of transcription of genes promoted via hormone responsive elements in our genome. Aberrant expression patterns and context-specific regulation of these receptors in cancer, have been routinely reported by multiple research groups. These gave an window of opportunity to target those receptors in the context of developing novel, targeted anticancer therapeutics. Besides the development of a plethora of SHR-targeting synthetic ligands and the availability of their natural, hormonal ligands, development of many SHR-targeted, anticancer nano-delivery systems and theranostics, especially based on small molecules, have been reported. It is intriguing to realize that these cytoplasmic receptors have become a hot target for cancer selective delivery. This is in spite of the fact that these receptors do not fall in the category of conventional, targetable cell surface bound or transmembrane receptors that enjoy over-expression status. Glucocorticoid receptor (GR) is one such exciting SHR that in spite of it being expressed ubiquitously in all cells, we discovered it to behave differently in cancer cells, thus making it a truly druggable target for treating cancer. This review selectively accumulates the knowledge generated in the field of SHR-targeting as a major focus for cancer treatment with various anticancer small molecules and nanotherapeutics on progesterone receptor, mineralocorticoid receptor, and androgen receptor while selectively emphasizing on GR and estrogen receptor. This review also briefly highlights lipid-modification strategy to convert ligands into SHR-targeted cancer nanotherapeutics. This article is categorized under: Therapeutic Approaches and Drug Discovery > Nanomedicine for Oncologic Disease Biology-Inspired Nanomaterials > Lipid-Based Structures Therapeutic Approaches and Drug Discovery > Emerging Technologies.

Promising applications of steroid сonjugates for cancer research and treatment

The conjugation of biologically active molecules is a powerful tool for drug discovery used to target a variety of multifunctional diseases including cancer. Conjugated drugs can provide combination therapies in a single multi-functional agent and, by doing so, be more specific and powerful than conventional classic treatments. Steroids are widely used for conjugation with other biological active molecules. This review refers to investigations of steroid conjugates as potential anticancer agents carried out mostly over the past decade. It consists of five parts in which the data concerning structure and anticancer activity of steroid conjugates with DNA alkylating agents, metallocomplexes, approved drugs, some biological active molecules, some natural compounds and related synthetic analogs are described.

Co-delivery of paclitaxel and curcumin by biodegradable polymeric nanoparticles for breast cancer chemotherapy

Multi-drug chemotherapy has been one of the most popular strategies for the treatment of malignant tumors, and has achieved desirable therapeutic outcomes. The objective of the present study is to develop biodegradable PCEC nanoparticles (NPs) for the co-delivery of paclitaxel (PTX) and curcumin (CUR), and investigate the antitumor effect of the drug delivery system (DDS: PTX-CUR-NPs) against breast cancer both in vitro and in vivo. The prepared PTX-CUR-NPs had a small size of 27.97 ± 1.87 nm with a low polydispersity index (PDI, 0.197 ± 0.040). The results exhibited slow release of PTX and CUR from the DDS without any burst effect. Further, the PTX-CUR-NPs displayed a dose-dependent cytotoxicity in MCF-7 cells with a higher apoptosis rate (64.29% ± 1.97%) as compared to that of free drugs (PTX + CUR, 34.21% ± 0.81%). The cellular uptake study revealed that the drug loaded PCEC polymeric nanoparticles were more readily uptaken by tumor cells in vitro. To evaluate the in vivo anti-tumor effect, the PTX-CUR-NPs were intravenously administered to BALB/c nude mouse xenografted with MCF-7 cells and the results exhibited significant inhibition of tumor growth with prolonged survival time and reduced side effect when compared with free drugs (PTX + CUR). Moreover, the administration of PTX-CUR-NPs treatment led to lower Ki67 expression (p < 0.05), and enhanced TUNEL positivity (higher apoptosis, p < 0.01) in tumor cells as compared to other treatment groups, suggesting the therapeutic efficacy of the DDS. Altogether, the present study suggests that the DDS PTX-CUR-NPs could be employed for the effective treatment of breast cancers in near future.

STAT3 transcription factor as target for anti-cancer therapy

STATs constitute a large family of transcription activators and transducers of signals that have an important role in many cell functions as regulation of proliferation and differentiation of the cell also regulation of apoptosis and angiogenesis. STAT3 as a member of that family, recently was discovered to have a vital role in progression of different types of cancers. The activation of STAT3 was observed to regulate multiple gene functions during cancer-like cell proliferation, differentiation, apoptosis, metastasis, inflammation, immunity, cell survival, and angiogenesis. The inhibition of STAT3 activation has been an important target for cancer therapy. Inhibitors of STAT3 have been used for a long time for treatment of many types of cancers like leukemia, melanoma, colon, and renal cancer. In this review article, we summarize and discuss different drugs inhibiting the action of STAT3 and used in treatment of different types of cancer.

Programmed cell death ligand-1: A dynamic immune checkpoint in cancer therapy

Antibody-based immunotherapies play a pivotal role in cancer research with efficient achievements in tumor suppression. Tumor survival is assisted by modulation of immune checkpoints to create imbalances between immune cells and cancer cell's environment. The modulation results in T-cell signal inhibition ultimately inert its proliferation and activation against various tumor cells. PD-L1, a 40 kDa transmembrane protein of B7 family, binds with PD-1 on the membrane of T cells which results in inhibition of T-cell proliferation and activation. PD-L1/PD-1 pathway has generated novel target sites for antibodies that can block PD-L1/PD-1 interactions. The blockage results in T-cell proliferation and tumor cell suppression. The PD-L1 immune checkpoint strategies' development, expression and regulations, signal inhibitions, and developmental stages of PD-L1/PD-1 antibodies are briefly discussed here in this review. All this information will provide a base for new therapeutic development against PD-L1 and PD-1 immune checkpoint interactions and will make available promising treatment options.

PDL-1 Antibody Drug Conjugate for Selective Chemo-Guided Immune Modulation of Cancer

Targeting immune checkpoint molecules such as programmed death ligand-1 (PDL1) is an emerging strategy for anti-cancer therapy. However, transient expression of PDL1 and difficulty in tumor stroma penetration has limited the utility of anti-PDL1 therapy. To overcome these limitations, we report a new conjugate between the clinically approved PDL1 antibody (PDL1 AB) and drug Doxorubicin (Dox), named PDL1-Dox. We conjugated PDL1-Dox through a hydrazone linker containing a polyethylene glycol (PEG) spacer, which allows it to dissociate in a tumor environment and improves solubility. The purpose of using Dox is to disrupt the tumor extracellular environment so that PDL-1 antibody can penetrate the tumor core. PDL1-Dox demonstrates significant cell killing, disruption of tumor spheroid and induction of apoptosis in a breast cancer cell line. Significant release of IFN-γ suggests PDL1-Dox can upmodulate T cell activation. Optical imaging of dye conjugate supports the selective tumor targeting ability and core penetration of the construct.

Therapeutically exploiting STAT3 activity in cancer - using tissue repair as a road map

The tightly orchestrated temporal and spatial control of signal transducer and activator of transcription 3 (STAT3) activity in epithelial, immune and stromal cells is critical for wound healing and tissue repair. Excessive STAT3 activation within cancer cells and cells of the tumour microenvironment can be viewed as a neoplastic mimic of an inflammation-driven repair response that collectively promotes tumour progression. In addition to the canonical transcriptional pathways by which STAT3 promotes stem cell-like characteristics, survival, proliferation, metastatic potential and immune evasion, cytoplasmic STAT3 activity fuels tumour growth by metabolic and other non-transcriptional mechanisms. Here, we review the tumour-modulating activities of STAT3 in light of its role as a signalling node integrating inflammatory responses during wound healing. Accordingly, many of the cytokines that contribute to the para-inflammatory state of most solid malignancies converge on and underpin dysregulated STAT3 activity. Targeting of these cytokines, their cognate receptors and associated signalling cascades in clinical trials is beginning to demonstrate therapeutic efficacy, given that interference with STAT3 activity is likely to simultaneously curb the growth of cancer cells and augment antitumour immunity.

Nano-engineered delivery systems for cancer imaging and therapy: Recent advances, future direction and patent evaluation

Cancer is the second highest cause of death worldwide. Several therapeutic approaches, such as conventional chemotherapy, antibodies and small molecule inhibitors and nanotherapeutics have been employed in battling cancer. Amongst them, nanotheranostics is an example of successful personalized medicine bearing dual role of early diagnosis and therapy to cancer patients. In this review, we have focused on various types of theranostic polymer and metal nanoparticles for their role in cancer therapy and imaging concerning their limitation, future application such as dendritic cell cancer vaccination, gene delivery, T-cell activation and immune modulation. Also, some of the recorded patent applications and clinical trials have been illustrated. The impact of the biological microenvironment on the biodistribution and accumulation of nanoparticles have been discussed.

Molecular Docking Analysis of Caspase-3 Activators as Potential Anticancer Agents

Introduction:

Caspase-3 plays a leading role in apoptosis and on activation, it cleaves many protein substrates in cells and causes cell death. Since many chemotherapeutics are known to induce apoptosis in cancer cells, promotion or activation of apoptosis via targeting apoptosis regulators has been suggested as a promising strategy for anticancer drug discovery. In this paper, we studied the interaction of 1,2,4-Oxadiazoles derivatives with anticancer drug target enzymes (PDB ID 3SRC).

Methods:

Molecular docking studies were performed on a series of 1,2,4-Oxadiazoles derivatives to find out molecular arrangement and spatial requirements for their binding potential for caspase-3 enzyme agonistic affinity to treat cancer. The Autodock 4.2 and GOLD 5.2 molecular modeling suites were used for the molecular docking analysis to provide information regarding important drug receptor interaction.

Results and Conclusion:

Both suites explained the spatial disposition of the drug with the active amino acid in the ligand binding domain of the enzyme. The amino acid asparagine 273 (ASN 273) of target has shown hydrogen bond interaction with the top ranked ligand.

Tumor hypoxia directed multimodal nanotherapy for overcoming drug resistance in renal cell carcinoma and reprogramming macrophages

Drug resistance is one of the significant clinical burden in renal cell carcinoma (RCC). The development of drug resistance is attributed to many factors, including impairment of apoptosis, elevation of carbonic anhydrase IX (CA IX, a marker of tumor hypoxia), and infiltration of tumorigenic immune cells. To alleviate the drug resistance, we have used Sorafenib (Sor) in combination with tumor hypoxia directed nanoparticle (NP) loaded with a new class of apoptosis inducer, CFM 4.16 (C4.16), namely CA IX-C4.16. The NP is designed to selectively deliver the payload to the hypoxic tumor (core), provoke superior cell death in parental (WT) and Everolimus-resistant (Evr-res) RCC and selectively downmodulate tumorigenic M2-macrophage. Copper-free 'click' chemistry was utilized for conjugating SMA-TPGS with Acetazolamide (ATZ, a CA IX-specific targeting ligand). The NP was further tagged with a clinically approved NIR dye (S0456) for evaluating hypoxic tumor core penetration and organ distribution. Imaging of tumor spheroid treated with NIR dye-labeled CA IX-SMA-TPGS revealed remarkable tumor core penetration that was modulated by CA IX-mediated targeting in hypoxic-A498 RCC cells. The significant cell killing effect with synergistic combination index (CI) of CA IX-C4.16 and Sor treatment suggests efficient reversal of Evr-resistance in A498 cells. The CA IX directed nanoplatform in combination with Sor has shown multiple benefits in overcoming drug resistance through (i) inhibition of p-AKT, (ii) upregulation of tumoricidal M1 macrophages resulting in induction of caspase 3/7 mediated apoptosis of Evr-res A498 cells in macrophage-RCC co-culturing condition, (iii) significant in vitro and in vivo Evr-res A498 tumor growth inhibition as compared to individual therapy, and (iv) untraceable liver and kidney toxicity in mice. Near-infrared (NIR) imaging of CA IX-SMA-TPGS-S0456 in Evr-res A498 RCC model exhibited significant accumulation of CA IX-oligomer in tumor core with >3-fold higher tumor uptake as compared to control. In conclusion, this proof-of-concept study demonstrates versatile tumor hypoxia directed nanoplatform that can work in synergy with existing drugs for reversing drug-resistance in RCC accompanied with re-education of tumor-associated macrophages, that could be applied universally for several hypoxic tumors.

Multifunctional nanoparticles for cancer immunotherapy: A groundbreaking approach for reprogramming malfunctioned tumor environment

Several cancer immunotherapy approaches have been recently introduced into the clinics and they have shown remarkable therapeutic potentials. The groundbreaking cancer immunotherapeutic agents function as a stimulant or modulator of the body immune system to fight against or kill cancers. Although targeted immunotherapies such as immune check point inhibitors (CTLA-4 or PD-1/PD-L1), DNA vaccination and CAR-T therapy are revolutionizing cancer treatment, the delivery efficacy can be further improved while their off-target toxicity can be mitigated through nanotechnology approaches. Recent research has demonstrated that nanotechnology has multifaceted role for (i) reeducating tumor associated macrophages (TAM) to function as tumor suppressor agent, (ii) serving as an efficient alternative for Chimeric Antigen Receptor (CAR)-T cell generation and transduction, and (iii) selective knockdown of Kras oncogene addiction by nano-Crisper-Cas9 delivery system. The function of host immune stimulatory signals and tumor immunotherapies can further be improved by repurposing of nanomedicine platform. This review summarizes the role of multifunctional polymeric, lipid, metallic and cell based nanoparticles for improving current immunotherapy.

A tumor multicomponent targeting chemoimmune drug delivery system for reprograming the tumor microenvironment and personalized cancer therapy

Nanoparticle library engineered with tunable size, shape, and geometry will provide a better idea of targeting multicomponent of tumor microenvironment consisting of epithelial cells, tumor hypoxia, tumor immune cells and angiogenic blood vessels.

Copper-Free 'Click' Chemistry-Based Synthesis and Characterization of Carbonic Anhydrase-IX Anchored Albumin-Paclitaxel Nanoparticles for Targeting Tumor Hypoxia

Triple negative breast cancer (TNBC) is a difficult to treat disease due to the absence of the three unique receptors estrogen, progesterone and herceptin-2 (HER-2). To improve the current therapy and overcome the resistance of TNBC, there is unmet need to develop an effective targeted therapy. In this regard, one of the logical and economical approaches is to develop a tumor hypoxia-targeting drug formulation platform for selective delivery of payload to the drug-resistant and invasive cell population of TNBC tumors. Toward this, we developed a Carbonic Anhydrase IX (CA IX) receptor targeting human serum albumin (HSA) carriers to deliver the potent anticancer drug, Paclitaxel (PTX). We used Acetazolamide (ATZ), a small molecule ligand of CA IX to selectively deliver HSA-PTX in TNBC cells. A novel method of synthesis involving copper free ‘click’ chemistry (Dibenzocyclooctyl, DBCO) moiety with an azide-labeled reaction partner, known as Strain-Promoted Alkyne Azide Cycloaddition (SPAAC) along with a desolvation method for PTX loading were used in the present study to arrive at the CA IX selective nano-carriers, HSA-PTX-ATZ. The anticancer effect of HSA-PTX-ATZ is higher compared to HSA, PTX and non-targeted HSA-PTX in MDA-MB-231 and MDA-MB-468 cells. The cell killing effect is associated with induction of early and late phases of apoptosis. Overall, our proof-of-concept study shows a promising avenue for hypoxia-targeted drug delivery that can be adapted to several types of cancers.

A CARP-1 functional mimetic loaded vitamin E-TPGS micellar nano-formulation for inhibition of renal cell carcinoma

Current treatments for Renal Cell Carcinoma (RCC) include a combination of surgery, targeted therapy, and immunotherapy. Emergence of resistant RCCs contributes to failure of drugs and poor prognosis, and thus warrants development of new and improved treatment options for RCCs. Here we generated and characterized RCC cells that are resistant to Everolimus, a frontline mToR-targeted therapy, and tested whether our novel class of CARP-1 functional mimetic (CFM) compounds inhibit parental and Everolimus-resistant RCC cells. CFMs inhibited RCC cell viability in a dose-dependent manner that was comparable to Everolimus treatments. The GI₅₀ dose of Everolimus for parental A498 cells was ∼1.2μM while it was <0.02μM for the parental UOK262 and UOK268 cells. The GI₅₀ dose for Everolimus-resistant A498, UOK262, and UOK268 cells were ≥10.0μM, 1.8-7.0μM, and 7.0-≥10.0μM, respectively. CFM-4 and its novel analog CFM-4.16 inhibited viabilities of Everolimus resistant RCC cells albeit CFM-4.16 was more effective than CFM-4. CFM-dependent loss of RCC cell viabilities was due in part to reduced cyclin B1 levels, activation of pro-apoptotic, stress-activated protein kinases (SAPKs), and apoptosis. CFM-4.16 suppressed growth of resistant RCC cells in three-dimensional suspension cultures. However, CFMs are hydrophobic and their intravenous administration and dose escalation for in-vivo studies remain challenging. In this study, we encapsulated CFM-4.16 in Vitamin-E TPGS-based- nanomicelles that resulted in its water-soluble formulation with higher CFM-4.16 loading (30% w/w). This CFM-4.16 formulation inhibited viability of parental and Everolimus-resistant RCC cells in vitro, and suppressed growth of parental A498 RCC-cell-derived xenografts in part by stimulating apoptosis. These findings portent promising therapeutic potential of CFM-4.16 for treatment of RCCs.

PD-1 and PD-L1 Checkpoint Signaling Inhibition for Cancer Immunotherapy: Mechanism, Combinations, and Clinical Outcome

Several cancers are highly refractory to conventional chemotherapy. The survival of tumors in several cases is assisted by checkpoint immunomodulation to maintain the imbalance between immune surveillance and cancer cell proliferation. Check point antibody inhibitors, such as anti-PD-1/PD-L1, are a novel class of inhibitors that function as a tumor suppressing factor via modulation of immune cell-tumor cell interaction. These checkpoint blockers are rapidly becoming a highly promising cancer therapeutic approach that yields remarkable antitumor responses with limited side effects. In recent times, more than four check point antibody inhibitors have been commercialized for targeting PD-1, PDL-1, and CTLA-4. Despite the huge success and efficacy of the anti-PD therapy response, it is limited to specific types of cancers, which attributes to the insufficient and heterogeneous expression of PD-1 in the tumor microenvironment. Herein, we review the current landscape of the PD-1/PD-L1 mechanistic role in tumor immune evasion and therapeutic outcome for cancer treatment. We also review the current progress in clinical trials, combination of drug therapy with immunotherapy, safety, and future of check point inhibitors for multiple types of cancer.

Design, synthesis and antiproliferative activity of decarbonyl luotonin analogues

A small library of benzimidazole-fused pyrrolo[3,4-b]quinoline has been synthesized from readily available benzimidazole 2-carbaldehyde and various substituted arylamines in good to excellent yields utilizing an intramolecular Povarov reaction catalyzed by boron trifluoride diethyl etharate as the key final step. The compounds thus synthesized can be considered as decarbonyl analogues of the anticancer alkaloid luotonin A and were evaluated in a DNA relaxation assay for their ability to inhibit human topoisomerase I. Interestingly, two of the compounds showed a remarkable activity that is comparable to that of the standard drug camptothecin. The compounds were also evaluated for their cytotoxic effect in four highly aggressive human cancer cell lines, namely KB, MDA-MB231 (breast), LNCap (prostate), and HT1080 (fibrosarcoma). Some of the compounds obtained showed promising cytotoxicities for these four cell lines.