Current Advancements in Anti-Cancer Chimeric Antigen Receptor T Cell Immunotherapy and How Nanotechnology May Change the Game.

Chimeric antigen receptor (CAR)-T cell immunotherapy represents a cutting-edge advancement in the landscape of cancer treatment. This innovative therapy has shown exceptional promise in targeting and eradicating malignant tumors, specifically leukemias and lymphomas. However, despite its groundbreaking successes, (CAR)-T cell therapy is not without its challenges. These challenges, particularly pronounced in the treatment of solid tumors, include but are not limited to, the selection of appropriate tumor antigens, managing therapy-related toxicity, overcoming T-cell exhaustion, and addressing the substantial financial costs associated with treatment. Nanomedicine, an interdisciplinary field that merges nanotechnology with medical science, offers novel strategies that could potentially address these limitations. Its application in cancer treatment has already led to significant advancements, including improved specificity in drug targeting, advancements in cancer diagnostics, enhanced imaging techniques, and strategies for long-term cancer prevention. The integration of nanomedicine with (CAR)-T cell therapy could revolutionize the treatment landscape by enhancing the delivery of genes in (CAR)-T cell engineering, reducing systemic toxicity, and alleviating the immunosuppressive effects within the tumor microenvironment. This review aims to explore how far (CAR)-T cell immunotherapy has come alone, and how nanomedicine could strengthen it into the future. Additionally, the review will examine strategies to limit the off-target effects and systemic toxicity associated with (CAR)-T cell therapy, potentially enhancing patient tolerance and treatment outcomes.

Targeting Farnesoid X Receptor in Tumor and the Tumor Microenvironment: Implication for Therapy.

The farnesoid-X receptor (FXR), a member of the nuclear hormone receptor superfamily, can be activated by bile acids (BAs). BAs binding to FXR activates BA signaling which is important for maintaining BA homeostasis. FXR is differentially expressed in human organs and exists in immune cells. The dysregulation of FXR is associated with a wide range of diseases including metabolic disorders, inflammatory diseases, immune disorders, and malignant neoplasm. Recent studies have demonstrated that FXR influences tumor cell progression and development through regulating oncogenic and tumor-suppressive pathways, and, moreover, it affects the tumor microenvironment (TME) by modulating TME components. These characteristics provide a new perspective on the FXR-targeted therapeutic strategy in cancer. In this review, we have summarized the recent research data on the functions of FXR in solid tumors and its influence on the TME, and discussed the mechanisms underlying the distinct function of FXR in various types of tumors. Additionally, the impacts on the TME by other BA receptors such as takeda G protein-coupled receptor 5 (TGR5), sphingosine-1-phosphate receptor 2 (S1PR2), and muscarinic receptors (CHRM2 and CHRM3), have been depicted. Finally, the effects of FXR agonists/antagonists in a combination therapy with PD1/PD-L1 immune checkpoint inhibitors and other anti-cancer drugs have been addressed.

New and Emerging Targeted Therapies for Advanced Breast Cancer.

In the United States, breast cancer is among the most frequently diagnosed cancers in women. Breast cancer is classified into four major subtypes: human epidermal growth factor receptor 2 (HER2), Luminal-A, Luminal-B, and Basal-like or triple-negative, based on histopathological criteria including the expression of hormone receptors (estrogen receptor and/or progesterone receptor) and/or HER2. Primary breast cancer treatments can include surgery, radiation therapy, systemic chemotherapy, endocrine therapy, and/or targeted therapy. Endocrine therapy has been shown to be effective in hormone receptor-positive breast cancers and is a common choice for adjuvant therapy. However, due to the aggressive nature of triple-negative breast cancer, targeted therapy is becoming a noteworthy area of research in the search for non-endocrine-targets in breast cancer. In addition to HER2-targeted therapy, other emerging therapies include immunotherapy and targeted therapy against critical checkpoints and/or pathways in cell growth. This review summarizes novel targeted breast cancer treatments and explores the possible implications of combination therapy.

Breast Cancer Predisposition Genes and Synthetic Lethality.

BRCA1 and BRCA2 are tumor suppressor genes with pivotal roles in the development of breast and ovarian cancers. These genes are essential for DNA double-strand break repair via homologous recombination (HR), which is a virtually error-free DNA repair mechanism. Following BRCA1 or BRCA2 mutations, HR is compromised, forcing cells to adopt alternative error-prone repair pathways that often result in tumorigenesis. Synthetic lethality refers to cell death caused by simultaneous perturbations of two genes while change of any one of them alone is nonlethal. Therefore, synthetic lethality can be instrumental in identifying new therapeutic targets for BRCA1/2 mutations. PARP is an established synthetic lethal partner of the BRCA genes. Its role is imperative in the single-strand break DNA repair system. Recently, Olaparib (a PARP inhibitor) was approved for treatment of BRCA1/2 breast and ovarian cancer as the first successful synthetic lethality-based therapy, showing considerable success in the development of effective targeted cancer therapeutics. Nevertheless, the possibility of drug resistance to targeted cancer therapy based on synthetic lethality necessitates the development of additional therapeutic options. This literature review addresses cancer predisposition genes, including BRCA1, BRCA2, and PALB2, synthetic lethality in the context of DNA repair machinery, as well as available treatment options.

A triple exon-skipping luciferase reporter assay identifies a new CLK inhibitor pharmacophore.

The splicing of pre-mRNA is a critical process in normal cells and is deregulated in cancer. Compounds that modulate this process have recently been shown to target a specific vulnerability in tumors. We have developed a novel cell-based assay that specifically activates luciferase in cells exposed to SF3B1 targeted compounds, such as sudemycin D6. This assay was used to screen a combined collection of approved drugs and bioactive compounds. This screening approach identified several active hits, the most potent of which were CGP-74514A and aminopurvalanol A, both have been reported to be cyclin-dependent kinases (CDKs) inhibitors. We found that these compounds, and their analogs, show significant cdc2-like kinase (CLK) inhibition and clear structure-activity relationships (SAR) at CLKs. We prepared a set of analogs and were able to 'dial out' the CDK activity and simultaneously developed CLK inhibitors with low nanomolar activity. Thus, we have demonstrated the utility of our exon-skipping assay and identified new molecules that exhibit potency and selectivity for CLK, as well as some structurally related dual CLK/CDK inhibitors.

Perturbation of the Vacuolar ATPase: A NOVEL CONSEQUENCE OF INOSITOL DEPLETION.

Depletion of inositol has profound effects on cell function and has been implicated in the therapeutic effects of drugs used to treat epilepsy and bipolar disorder. We have previously shown that the anticonvulsant drug valproate (VPA) depletes inositol by inhibiting myo-inositol-3-phosphate synthase, the enzyme that catalyzes the first and rate-limiting step of inositol biosynthesis. To elucidate the cellular consequences of inositol depletion, we screened the yeast deletion collection for VPA-sensitive mutants and identified mutants in vacuolar sorting and the vacuolar ATPase (V-ATPase). Inositol depletion caused by starvation of ino1Δ cells perturbed the vacuolar structure and decreased V-ATPase activity and proton pumping in isolated vacuolar vesicles. VPA compromised the dynamics of phosphatidylinositol 3,5-bisphosphate (PI3,5P2) and greatly reduced V-ATPase proton transport in inositol-deprived wild-type cells. Osmotic stress, known to increase PI3,5P2 levels, did not restore PI3,5P2 homeostasis nor did it induce vacuolar fragmentation in VPA-treated cells, suggesting that perturbation of the V-ATPase is a consequence of altered PI3,5P2 homeostasis under inositol-limiting conditions. This study is the first to demonstrate that inositol depletion caused by starvation of an inositol synthesis mutant or by the inositol-depleting drug VPA leads to perturbation of the V-ATPase.

Tumor STAT1 transcription factor activity enhances breast tumor growth and immune suppression mediated by myeloid-derived suppressor cells.

Previous studies had implicated the IFN-γ transcription factor signal transducer and activator of transcription 1 (STAT1) as a tumor suppressor. However, accumulating evidence has correlated increased STAT1 activation with increased tumor progression in multiple types of cancer, including breast cancer. Indeed, we present evidence that tumor up-regulation of STAT1 activity in human and mouse mammary tumors correlates with increasing disease progression to invasive carcinoma. A microarray analysis comparing low aggressive TM40D and highly aggressive TM40D-MB mouse mammary carcinoma cells revealed significantly higher STAT1 activity in the TM40D-MB cells. Ectopic overexpression of constitutively active STAT1 in TM40D cells promoted mobilization of myeloid-derived suppressor cells (MDSCs) and inhibition of antitumor T cells, resulting in aggressive tumor growth in tumor-transplanted, immunocompetent mice. Conversely, gene knockdown of STAT1 in the metastatic TM40D-MB cells reversed these events and attenuated tumor progression. Importantly, we demonstrate that in human breast cancer, the presence of tumor STAT1 activity and tumor-recruited CD33(+) myeloid cells correlates with increasing disease progression from ductal carcinoma in situ to invasive carcinoma. We conclude that STAT1 activity in breast cancer cells is responsible for shaping an immunosuppressive tumor microenvironment, and inhibiting STAT1 activity is a promising immune therapeutic approach.

Protein phosphorylation and kinases: Potential therapeutic targets in necroptosis.

Necroptosis is a pivotal contributor to the pathogenesis of various human diseases, including those affecting the nervous system, cardiovascular system, pulmonary system, and kidneys. Extensive investigations have elucidated the mechanisms and physiological ramifications of necroptosis. Among these, protein phosphorylation emerges as a paramount regulatory process, facilitating the activation or inhibition of specific proteins through the addition of phosphate groups to their corresponding amino acid residues. Currently, the targeting of kinases has gained recognition as a firmly established and efficacious therapeutic approach for diverse diseases, notably cancer. In this comprehensive review, we elucidate the intricate role of phosphorylation in governing key molecular players in the necroptotic pathway. Moreover, we provide an in-depth analysis of recent advancements in the development of kinase inhibitors aimed at modulating necroptosis. Lastly, we deliberate on the prospects and challenges associated with the utilization of kinase inhibitors to modulate necroptotic processes.

The RELT Family of Proteins: An Increasing Awareness of Their Importance for Cancer, the Immune System, and Development.

This review highlights Receptor Expressed in Lymphoid Tissues (RELT), a Tumor Necrosis Factor Superfamily member, and its two paralogs, RELL1 and RELL2. Collectively, these three proteins are referred to as RELTfms and have gained much interest in recent years due to their association with cancer and other human diseases. A thorough knowledge of their physiological functions, including the ligand for RELT, is lacking, yet emerging evidence implicates RELTfms in a variety of processes including cytokine signaling and pathways that either promote cell death or survival. T cells from mice lacking RELT exhibit increased responses against tumors and increased inflammatory cytokine production, and multiple lines of evidence indicate that RELT may promote an immunosuppressive environment for tumors. The relationship of individual RELTfms in different cancers is not universal however, as evidence indicates that individual RELTfms may be risk factors in certain cancers yet appear to be protective in other cancers. RELTfms are important for a variety of additional processes related to human health including microbial pathogenesis, inflammation, behavior, reproduction, and development. All three proteins have been strongly conserved in all vertebrates, and this review aims to provide a clearer understanding of the current knowledge regarding these interesting proteins.

An effective up-sampling approach for breast cancer prediction with imbalanced data: A machine learning model-based comparative analysis.

Early detection of breast cancer plays a critical role in successful treatment that saves thousands of lives of patients every year. Despite massive clinical data have been collected and stored by healthcare organizations, only a small portion of the data has been used to support decision-making for treatments. In this study, we proposed an engineered up-sampling method (ENUS) for handling imbalanced data to improve predictive performance of machine learning models. Our experiment results showed that when the ratio of the minority to the majority class is less than 20%, training models with ENUS improved the balanced accuracy 3.74%, sensitivity 8.36% and F1 score 3.83%. Our study also identified that XGBoost Tree (XGBTree) using ENUS achieved the best performance with an average balanced accuracy of 97.47% (min = 93%, max = 100%), sensitivity of 97.88% (min = 89% and max = 100%), and F1 score of 96.20% (min = 89.5%, max = 100%) in the validation dataset. Furthermore, our ensemble algorithm identified Cell_Shape and Nuclei as the most important attributes in predicting breast cancer. The finding re-affirms the previous knowledge of the relationship between Cell_Shape, Nuclei, and the grades of breast cancer using a data-driven approach. Finally, our experiment showed that Random Forest and Neural Network models had the least training time. Our study provided a comprehensive comparison of a wide range of machine learning methods in predicting breast cancer risk. It can be used as a tool for healthcare practitioners to effectively detect and treat breast cancer.

Emerging Novel Combined CAR-T Cell Therapies.

Chimeric antigen receptors (CAR) T cells are T cells engineered to express membrane receptors with high specificity to recognize specific target antigens presented by cancer cells and are co-stimulated with intracellular signals to increase the T cell response. CAR-T cell therapy is emerging as a novel therapeutic approach to improve T cell specificity that will lead to advances in precision medicine. CAR-T cells have had impressive outcomes in hematological malignancies. However, there continue to be significant limitations of these therapeutic responses in targeting solid malignancies such as heterogeneous antigens in solid tumors, tumor immunosuppressive microenvironment, risk of on-target/off-tumor, infiltrating CAR-T cells, immunosuppressive checkpoint molecules, and cytokines. This review paper summarizes recent approaches and innovations through combination therapies of CAR-T cells and other immunotherapy or small molecule drugs to counter the above disadvantages to potentiate the activity of CAR-T cells.

SR16388: a steroidal antiangiogenic agent with potent inhibitory effect on tumor growth in vivo.

Angiogenesis is one of the major processes controlling growth and metastasis of tumors. Angiogenesis inhibitors have been targeted for the treatment of various cancers for more than 2 decades. We have developed a novel class of steroidal compounds aimed at blocking the angiogenic process in cancerous tissues. Our lead compound, SR16388, is a potent antiangiogenic agent with binding affinity to estrogen receptor-α (ER-α) and -ß (ER-ß) at the nanomolar range. This compound inhibited the proliferation of human microvascular endothelial cells (HMVEC) and various types of human cancer cells in vitro. SR16388 inhibited embryonic angiogenesis as measured in the chick chorioallantoic membrane (CAM) assay. The blood vessel density in the CAM was greatly reduced after the embryos were treated with 3 µg/CAM of SR16388 for 24 h. SR16388 at a dose of 2 µM prevented tube formation in Matrigel after HMVEC cells were treated for 8 h. In a modified Boyden chamber assay, SR16388 inhibited the migration of HMVECs by 80% at 500 nM. Using a novel in vivo Fibrin Z-chamber model, we demonstrated that SR16388 at a single daily oral dose of 3 mg/kg for 12 days significantly inhibited the granulation tissue (GT) thickness and the microvessel density of the GT as compared to control. More importantly, SR16388 down-regulated the pro-angiogenic transcription factors, hypoxia inducible factor 1α (HIF-1α) and signal transducer and activator of transcription 3 (STAT3) in non-small cell lung cancer (NSCLC) cells. Together, these effects of SR16388 can lead to the reduction of vascularization and tumor growth in vivo.

Chimeric antigen receptor T-cell immunotherapy in breast cancer: development and challenges.

Chimeric antigen receptor (CAR) T-cell therapy is an innovative form of immunotherapy wherein autologous T-cells are genetically modified to express chimeric receptors encoding an antigen-specific single-chain variable fragment and costimulatory molecules. Moreover, CAR T-cell therapy can only work successfully in patients who have an intact immune system. Therefore, patients receiving cytotoxic chemotherapy will be immunosuppressed making CAR-T therapy less effective. In adoptive CD8+ T-cell therapy (ACT), numerous tumor-specific, engineered T-cells are sourced from patients, expanded in vitro, and infused back expressing tumor-specific antigen receptors. The most successful ACT, anti-CD19 chimeric antigen receptor T-cell therapy directed against B-cell lymphoma, has proved to be efficacious. However, current efforts to utilize this approach for solid tumors, like breast cancer, have shown only modest improvement. Nevertheless, the potential efficacy of CAR-T therapy is promising in an era of immunological advances. By appropriately manipulating CAR T-cells to combat the immunosuppressive forces of the tumor microenvironment, significant eradication of the solid tumor may occur. This review discusses CAR T-cell therapy and its specificity and safety in adoptive cell transfers in breast cancer. We will highlight novel discoveries in CAR T-cell immunotherapy and the formidable barriers including suppression of T-cell function and localization at tumor sites.

RELT stains prominently in B-cell lymphomas and binds the hematopoietic transcription factor MDFIC.

Receptor Expressed in Lymphoid Tissues (RELT) is a human tumor necrosis factor receptor superfamily member (TNFRSF) that is expressed most prominently in cells and tissues of the hematopoietic system. RELL1 and RELL2 are two homologs that physically interact with RELT and co-localize with RELT at the plasma membrane. This study sought to further elucidate the function of RELT by identifying novel protein interactions with RELT family members. The transcription factor MyoD family inhibitor domain-containing (MDFIC) was identified in a yeast two-hybrid genetic screen using RELL1 as bait. MDFIC co-localizes with RELT family members at the plasma membrane; this co-localization was most prominently observed with RELL1 and RELL2. In vitro co-immunoprecipitation (Co-IP) was utilized to demonstrate that MDFIC physically interacts with RELT, RELL1, and RELL2. Co-IP using deletion mutants of MDFIC and RELT identified regions important for physical association between MDFIC and RELT family members and a computational analysis revealed that RELT family members are highly disordered proteins. Immunohistochemistry of normal human lymph nodes revealed RELT staining that was most prominent in macrophages. Interestingly, the level of RELT staining significantly increased progressively in low and high-grade B-cell lymphomas versus normal lymph nodes. RELT co-staining with CD20 was observed in B-cell lymphomas, indicating that RELT is expressed in malignant B cells. Collectively, these results further our understanding of RELT-associated signaling pathways, the protein structure of RELT family members, and provide preliminary evidence indicating an association of RELT with B-cell lymphomas.

An exon skipping screen identifies antitumor drugs that are potent modulators of pre-mRNA splicing, suggesting new therapeutic applications.

Agents that modulate pre-mRNA splicing are of interest in multiple therapeutic areas, including cancer. We report our recent screening results with the application of a cell-based Triple Exon Skipping Luciferase Reporter (TESLR) using a library that is composed of FDA approved drugs, clinical compounds, and mechanistically characterized tool compounds. Confirmatory assays showed that three clinical antitumor therapeutic candidates (milciclib, PF-3758309 and PF-562271) are potent splicing modulators and that these drugs are, in fact, nanomolar inhibitors of multiple kinases involved in the regulation the spliceosome. We also report the identification of new SF3B1 antagonists (sudemycinol C and E) and show that these antagonists can be used to develop a displacement assay for SF3B1 small molecule ligands. These results further support the broad potential for the development of agents that target the spliceosome for the treatment of cancer and other diseases, as well as new avenues for the discovery of new chemotherapeutic agents for a range of diseases.

Metallothionein induction by hypoxia involves cooperative interactions between metal-responsive transcription factor-1 and hypoxia-inducible transcription factor-1alpha.

Mammalian metallothionein (MT) genes are transcriptionally activated by the essential metal zinc as well as by environmental stresses, including toxic metal overload and redox fluctuations. In addition to playing a key role in zinc homeostasis, MT proteins can protect against metal- and oxidant-induced cellular damage, and may participate in other fundamental physiologic and pathologic processes such as cell survival, proliferation, and neoplasia. Previously, our group reported a requirement for metal-responsive transcription factor-1 (MTF-1) in hypoxia-induced transcription of mouse MT-I and human MT-IIA genes. Here, we provide evidence that the protumorigenic hypoxia-inducible transcription factor-1alpha (HIF-1alpha) is essential for induction of MT-1 by hypoxia, but not zinc. Chromatin immunoprecipitation assays revealed that MTF-1 and HIF-1alpha are both recruited to the mouse MT-I promoter in response to hypoxia, but not zinc. In the absence of HIF-1alpha, MTF-1 is recruited to the MT-I promoter but fails to activate MT-I gene expression in response to hypoxia. Thus, HIF-1alpha seems to function as a coactivator of MT-I gene transcription by interacting with MTF-1 during hypoxia. Coimmunoprecipitation studies suggest interaction between MTF-1 and HIF-1alpha, either directly or as mediated by other factors. It is proposed that association of these important transcription factors in a multiprotein complex represents a common strategy to control unique sets of hypoxia-inducible genes in both normal and diseased tissue.

Epigenetic alteration of the Wnt inhibitory factor-1 promoter occurs early in the carcinogenesis of Barrett's esophagus.

The role of Wnt antagonists in the carcinogenesis of esophageal adenocarcinoma (EAC) remains unclear. We hypothesized that downregulation of the Wnt inhibitory factor-1 (WIF-1) might be involved in the neoplastic progression of Barrett's esophagus (BE). We analyzed the DNA methylation status of the WIF-1 promoter in normal, preneoplastic, and neoplastic samples from BE patients and in EAC cell lines. We investigated the role of WIF-1 on EAC cell growth and the chemosensitization of the cells to cisplatin. We found that silencing of WIF-1 correlated with promoter hypermethylation. EAC tissue samples showed higher levels of WIF-1 methylation compared to the matched normal epithelium. In addition, we found that WIF-1 hypermethylation was more frequent in BE samples from patients with EAC than in BE samples from patients who had not progressed to EAC. Restoration of WIF-1 in cell lines where WIF-1 was methylation-silenced resulted in growth suppression. Restoration of WIF-1 could sensitize the EAC cells to the chemotherapy drug cisplatin. Our results suggest that silencing of WIF-1 through promoter hypermethylation is an early and common event in the carcinogenesis of BE. Restoring functional WIF-1 might be used as a new targeted therapy for the treatment of this malignancy.