Overcoming Acquired Drug Resistance to Cancer Therapies through Targeted STAT3 Inhibition

Photothermal treatment of prostate tumor with micellar indocyanine green and napabucasin to co-ablate cancer cells and cancer stem cells

Advanced prostate cancer is hassled by relapse and metastasis that are closely associated with cancer stem cells (CSCs). Here, we present micellar indocyanine green and napabucasin (mICG-Nap) that co-ablates cancer cells and CSCs via photothermal therapy (PTT) for the treatment of prostate tumor. mICG-Nap with stable loading of both drugs and favorable size effectively reduced CSC population in RM1-PSMA murine prostate cancer cells and inhibited tumor spheroid formation. mICG-Nap showed an enhanced photothermal effect compared with free ICG and eliminated tumor spheroids under near-infrared (NIR) irradiation. The efficacy of mICG-Nap was further enhanced by decorating with Acupa ligand, which targets to RM1-PSMA cells and tumors via PSMA receptor. The enhanced tumor cell uptake of Acupa-mICG-Nap led to significant survival benefits in both subcutaneous RM1-PSMA tumor models and postoperative models. The tumor analyses demonstrated clear downregulation of CSC-related biomarkers such as OCT4, SOX2, CD133 and pSTAT3 as well as PSMA by Acupa-mICG-Nap. Rational formulated micellar indocyanine green and napabucasin plus NIR appears as an appealing strategy to co-ablate cancer cells and CSCs with rapid tumor de-bulking yet no recurrence.

STAT3 Signaling Pathway in Health and Disease

Signal transducer and activator of transcription 3 (STAT3) is a critical transcription factor involved in multiple physiological and pathological processes. While STAT3 plays an essential role in homeostasis, its persistent activation has been implicated in the pathogenesis of various diseases, particularly cancer, bone-related diseases, autoimmune disorders, inflammatory diseases, cardiovascular diseases, and neurodegenerative conditions. The interleukin-6/Janus kinase (JAK)/STAT3 signaling axis is central to STAT3 activation, influencing tumor microenvironment remodeling, angiogenesis, immune evasion, and therapy resistance. Despite extensive research, the precise mechanisms underlying dysregulated STAT3 signaling in disease progression remain incompletely understood, and no United States Food and Drug Administration (USFDA)-approved direct STAT3 inhibitors currently exist. This review provides a comprehensive evaluation of STAT3's role in health and disease, emphasizing its involvement in cancer stem cell maintenance, metastasis, inflammation, and drug resistance. We systematically discuss therapeutic strategies, including JAK inhibitors (tofacitinib, ruxolitinib), Src Homology 2 domain inhibitors (S3I-201, STATTIC), antisense oligonucleotides (AZD9150), and nanomedicine-based drug delivery systems, which enhance specificity and bioavailability while reducing toxicity. By integrating molecular mechanisms, disease pathology, and emerging therapeutic interventions, this review fills a critical knowledge gap in STAT3-targeted therapy. Our insights into STAT3 signaling crosstalk, epigenetic regulation, and resistance mechanisms offer a foundation for developing next-generation STAT3 inhibitors with greater clinical efficacy and translational potential.

Pathogenetic development, diagnosis and clinical therapeutic approaches for liver metastasis from colorectal cancer (Review)

Colorectal cancer (CRC) is a prevalent malignancy and a significant proportion of patients with CRC develop liver metastasis (CRLM), which is a major contributor to CRC‑related mortality. The present review aimed to comprehensively examine the pathogenetic development and diagnosis of CRLM and the clinical therapeutic approaches for treatment of this disease. The molecular mechanisms underlying CRLM were discussed, including the role of the tumour microenvironment and epithelial‑mesenchymal transition. The present review also highlighted the importance of early detection and the current challenges in predicting the development of CRLM. Various treatment strategies were reviewed, including surgical resection, chemotherapy and immunotherapy, and the potential of novel therapies, such as selective internal radiation therapy and Traditional Chinese Medicine. Despite recent advancements in treatment options, the treatment of CRLM remains a therapeutic challenge due to the complexity of the liver microenvironment and the heterogeneity of CRC. The present review emphasized the need for a multidisciplinary approach and the integration of emerging therapies to improve patient outcomes.

Napabucasin deactivates STAT3 and promotes mitoxantrone-mediated cGAS-STING activation for hepatocellular carcinoma chemo-immunotherapy

The immune resistance of tumor microenvironment (TME) causes immune checkpoint blockade therapy inefficient to hepatocellular carcinoma (HCC). Emerging strategies of using chemotherapy regimens to reverse the immune resistance provide the promise for promoting the efficiency of immune checkpoint inhibitors. The induction of cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS)-stimulator of interferon genes (STING) in tumor cells evokes the adaptive immunity and remodels the immunosuppressive TME. In this study, we report that mitoxantrone (MIT, a chemotherapeutic drug) activates the cGAS-STING signaling pathway of HCC cells. We provide an approach to augment the efficacy of MIT using a signal transducer and activator of transcription 3 (STAT3) inhibitor called napabucasin (NAP). We prepare an aminoethyl anisamide (AEAA)-targeted polyethylene glycol (PEG)-modified poly (lactic-co-glycolic acid) (PLGA)-based nanocarrier for co-delivery of MIT and NAP. The resultant co-nanoformulation can elicit the cGAS-STING-based immune responses to reshape the immunoresistant TME in the mice orthotopically grafted with HCC. Consequently, the resultant co-nanoformulation can promote anti-PD-1 antibody for suppressing HCC development, generating long-term survival, and inhibiting tumor recurrence. This study reveals the potential of MIT to activate the cGAS-STING signaling pathway, and confirms the feasibility of nano co-delivery for MIT and NAP on achieving HCC chemo-immunotherapy.

Dihydrotanshinone I enhanced BRAF mutant melanoma treatment efficacy by inhibiting the STAT3/SOX2 signaling pathway

BACKGROUND

The Food and Drug Administration has approved the Serine/threonine-protein kinase B-raf (BRAF) inhibitor and Mitogen-activated extracellular signal-regulated kinase (MEK) inhibitor combo as the first-line treatment for individuals with metastatic melanoma, although the majority of these patients exhibit primary or secondary drug resistance in the clinic. Dihydrotanshinone I (DHT) is a lipophilic compound extracted from the root of Salvia miltiorrhiza that has been linked to multiple antitumor activities. In this study, we investigated the effect of dihydrotanshinone I on the MAPK pathway inhibitor resistance of BRAF mutant malignant melanoma.

METHOD

After treating A375, A375R, and A2058 cells with DHT or a combination of DHT and BRAF/MEK inhibitors, WB and Real-Time RT-qPCR were used to confirm the activation of the MAPK and STAT3/SOX2 pathways. CCK-8 was used to assess cell viability, while flow cytometry was used to identify apoptosis. In addition, mice were inoculated with A375 cells to establish a model of tumour formation, and various drug groups and treatment models were utilized. The diameter and weight of tumours in each group were then measured, and IHC and HE staining were used to assess the expression of two pathways and cytotoxicity, respectively.

RESULTS

This study found that DHT directly interacts with STAT3 protein and it can stop the feedback activation of the STAT3/SOX2 pathway caused by the use of MAPK pathway inhibitors. In addition, the combination of DHT and BRAF/MEK inhibitors can inhibit the proliferation and growth of BRAF mutant melanoma cells and primary and secondary drug-resistant cells. Finally, we proved that the combined therapy of DHT and BRAF/MEK inhibitors is reliable and effective at animal and cell levels.

CONCLUSION

In BRAF mutant melanoma cells, DHT suppresses the STAT3/SOX2 signaling pathway. Combining DHT, BRAF inhibitors, and MEK inhibitors can help treat treatment-resistant BRAF mutant melanoma cells. Experimental results both in vitro and in vivo have shown that the combination of DHT and an inhibitor of the MAPK pathway is safer and more successful than using an inhibitor of the MAPK pathway alone when treating BRAF mutant melanoma.

Acquired resistance to tyrosine kinase targeted therapy: mechanism and tackling strategies

Over the past two decades, tyrosine kinase inhibitors (TKIs) have rapidly emerged as pivotal targeted agents, offering promising therapeutic prospects for patients. However, as the cornerstone of targeted therapies, an increasing number of TKIs have been found to develop acquired resistance during treatment, making the challenge of overcoming this resistance a primary focus of current research. This review comprehensively examines the evolution of TKIs from multiple perspectives, with particular emphasis on the mechanisms underlying acquired resistance, innovative drug design strategies, inherent challenges, and future directions.

Nitro-fatty acids: promising agents for the development of new cancer therapeutics

Nitro-fatty acids (NO2-FAs) are endogenous pleiotropic lipid mediators regarded as promising drug candidates for treating inflammatory and fibrotic diseases. Over the past two decades, the anti-inflammatory and cytoprotective actions of NO2-FAs and several molecular targets have been identified. More recently, preclinical studies have demonstrated their potential as prospective cancer therapeutics with favorable safety and tumor-selective profiles. In this review, we describe the mechanisms of action, with a focus on NO2-FA antineoplastic and chemosensitizing effects. We also address the potential therapeutic applications of endogenous and structurally modified NO2-FAs species in cancer treatment.

Structure, function, signaling pathways and clinical therapeutics: The translational potential of STAT3 as a target for cancer therapy

Cancer remains one of the most difficult human diseases to overcome because of its complexity and diversity. Signal transducers and transcriptional activators 3 (STAT3) protein has been found to be overexpressed in a wide range of cancer types. Hyperactivation of STAT3 is particularly associated with low survival in cancer patients. This review summarizes the specific molecular mechanisms of STAT3 in cancer development. STAT3 is activated by extracellular signals in the cytoplasm, interacts with different enzymes in the nucleus, mitochondria or endoplasmic reticulum, and subsequently participates in cancer development. The phosphorylated STAT3 at tyrosine 705 site (YP-STAT3) enters the nucleus and regulates a number of tumor-related biological processes such as angiogenesis, migration invasion, cell proliferation and cancer cell stemness. In contrast, the phosphorylated STAT3 at serine 727 site (SP-STAT3) is found on the mitochondria, affects electron respiration transport chain activity and thereby prevents tumor cell apoptosis. SP-STAT3 also appears on the mitochondria-associated endoplasmic reticulum membrane, influences the flow of Ca2+, and affects tumor progression. In addition, we summarize the direct and indirect inhibitors of STAT3 which are currently undergoing clinical studies. Some of them such as TTI101 and BBI608 have been approved by the FDA for the treatment of certain cancers. All in all, STAT3 plays an important role in cancer progression and becomes a potential target for cancer treatment.

A New IL-6-Inducing Mechanism in Cancer with New Therapeutic Possibilities

Background: Interleukin-6 is dysregulated in multiple pathological conditions, e.g., cancer and inflammatory diseases. Aim: To investigate new mechanisms for the regulation of pathological IL-6 production. Methods: PBMCs (peripheral blood mononuclear cells) stimulated by cancer serum factors or specific peptides produce interleukin-6 (IL-6). Immunoregulatory albumin neo-structures and peptides were identified with 2D gel electrophoresis and MALDI-TOF-MS (matrix-assisted laser desorption/ionization time-of-flight mass spectrometry) analyses. Il-6 and albumin neo-structures were determined by ELISA (enzyme-linked immunosorbent assay). Results: Conformational changes in normal serum albumin by proteolytic degradation generates an IL-6-inducing neo-structure, IL-6-inducing factor (IL-6IF). This neo-structure is immunogenic which results in the production of autoantibodies. IL-6 production induced by IL-6IF and cancer patient sera is inhibited by specific antibodies. The serum concentration of IL-6IF is significantly higher in advanced cancer stages, and its presence is significantly correlated with the survival of the patients. Conclusions: A new mechanism for the induction IL-6 synthesis is presented. Based on this mechanism, the pathological IL-6 production related to enhanced proteolytic activity can be diagnosed and selectively inhibited by specific antibodies. Such antibodies were identified and purified. Thus, the neo-structure, inducing pathological IL-6 production, associated with a reduced survival of cancer patients, can be selectively removed by the therapeutic administration of antibodies leaving the function of IL-6 needed for the normal activity of the immune system intact.

Targeting the STAT3 pathway with STAT3 degraders

Signal transducer and activator of transcription 3 (STAT3) has been widely considered as a therapeutic target for various diseases, especially tumors. Thus far, several STAT3 inhibitors have been advanced to clinical trials; however, the development of STAT3 inhibitors is hindered by numerous dilemmas. Fortunately, STAT3 degraders represent an alternative and promising strategy to block STAT3, attracting extensive research interest. Here, we analyze the recent advancements of STAT3 degraders, including proteolysis targeting chimeras (PROTACs) and small-molecule natural products, focusing on their structures, mechanisms, and biological activities. We discuss the potential opportunities and challenges for developing STAT3 degraders. It is hoped that this Review will provide insights into the discovery of potent STAT3-targeting drugs.

A Review of the Efficacy of Nanomaterial-Based Natural Photosensitizers to Overcome Multidrug Resistance in Cancer

Natural photosensitizers (PS) are compounds derived from nature, with photodynamic properties. Natural PSs have a similar action to that of commercial PSs, where cancer cell death occurs by necrosis, apoptosis, and autophagy through ROS generation. Natural PSs have garnered great interest over the last few decades because of their high biocompatibility and good photoactivity. Specific wavelengths could cause phytochemicals to produce harmful ROS for photodynamic therapy (PDT). However, natural PSs have some shortcomings, such as reduced solubility and lower uptake, making them less appropriate for PDT. Nanotechnology offers an opportunity to develop suitable carriers for various natural PSs for PDT applications. Various nanoparticles have been developed to improve the outcome with enhanced solubility, optical adsorption, and tumor targeting. Multidrug resistance (MDR) is a phenomenon in which tumor cells develop resistance to a wide range of structurally and functionally unrelated drugs. Over the last decade, several researchers have extensively studied the effect of natural PS-based photodynamic treatment (PDT) on MDR cells. Though the outcomes of clinical trials for natural PSs were inconclusive, significant advancement is still required before PSs can be used as a PDT agent for treating MDR tumors. This review addresses the increasing literature on MDR tumor progression and the efficacy of PDT, emphasizing the importance of developing new nano-based natural PSs in the fight against MDR that have the required features for an MDR tumor photosensitizing regimen.

STAT3 Pathways Contribute to β-HCH Interference with Anticancer Tyrosine Kinase Inhibitors

Organochlorine pesticides (OCPs) are a class of environmentally persistent and bioaccumulative pollutants. Among these, β-hexachlorocyclohexane (β-HCH) is a byproduct of lindane synthesis, one of the most worldwide widespread pesticides. β-HCH cellular mechanisms inducing chemical carcinogenesis correspond to many of those inducing chemoresistance, in particular, by the activation of signal transducer and activator of transcription 3 (STAT3) signaling pathways. For this purpose, four cell lines, representative of breast, lung, prostate, and hepatocellular cancers, were treated with β-HCH, specific tyrosine kinase inhibitors (TKIs), and a STAT3 inhibitor. All cell samples were analyzed by a viability assay, immunoblotting analysis, a wound-healing assay, and a colony formation assay. The results show that β-HCH reduces the efficacy of TKIs. The STAT3 protein, in this context, plays a central role. In fact, by inhibiting its activity, the efficacy of the anticancer drug is restored. Furthermore, this manuscript aimed to draw the attention of the scientific and socio-healthcare community to the issue of prolonged exposure to contaminants and their impact on drug efficacy.

Venetoclax resistance in acute myeloid leukaemia-Clinical and biological insights

Venetoclax, an oral BCL-2 inhibitor, has been widely incorporated in the treatment of acute myeloid leukaemia. The combination of hypomethylating agents and venetoclax is the current standard of care for elderly and patient's ineligible for aggressive therapies. However, venetoclax is being increasingly used with aggressive chemotherapy regimens both in the front line and in the relapse setting. Our growing experience and intensive research demonstrate that certain genetic abnormalities are associated with venetoclax sensitivity, while others with resistance, and that resistance can emerge during treatment leading to disease relapse. In the current review, we provide a summary of the known mechanisms of venetoclax cytotoxicity, both regarding the inhibition of BCL-2-mediated apoptosis and its effect on cell metabolism. We describe how these pathways are linked to venetoclax resistance and are associated with specific mutations. Finally, we provide the rationale for novel drug combinations in current and future clinical trials.

The oncogenic mechanisms of the Janus kinase-signal transducer and activator of transcription pathway in digestive tract tumors

Digestive tract tumors are heterogeneous and involve the dysregulation of multiple signaling pathways. The Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway plays a notable role in the oncogenesis of digestive tract tumors. Typically activated by pro-inflammatory cytokines, it regulates important biological processes, such as cell growth, differentiation, apoptosis, immune responses, and inflammation. The aberrant activation of this pathway manifests in different forms, including mutations in JAKs, overexpression of cytokine receptors, and sustained STAT activation, and contributes to promoting the malignant characteristics of cancer cells, including uncontrolled proliferation, resistance to apoptosis, enhanced invasion and metastasis, angiogenesis, acquisition of stem-like properties, and drug resistance. Numerous studies have shown that aberrant activation of the JAK-STAT pathway is closely related to the development and progression of digestive tract tumors, contributing to tumor survival, angiogenesis, changes in the tumor microenvironment, and even immune escape processes. In addition, this signaling pathway also affects the sensitivity of digestive tract tumors to chemotherapy and targeted therapy. Therefore, it is crucial to comprehensively understand the oncogenic mechanisms underlying the JAK-STAT pathway in order to develop effective therapeutic strategies against digestive tract tumors. Currently, several JAK-STAT inhibitors are undergoing clinical and preclinical trials as potential treatments for various human diseases. However, further investigation is required to determine the role of this pathway, as well as the effectiveness and safety of its inhibitors, especially in the context of digestive tract tumors. In this review, we provide an overview of the structure, classic activation, and negative regulation of the JAK-STAT pathway. Furthermore, we discuss the pathogenic mechanisms of JAK-STAT signaling in different digestive tract tumors, with the aim of identifying potential novel therapeutic targets. Video Abstract.

MiR-383 sensitizes osteosarcoma cells to bortezomib treatment via down-regulating PSMB5

BACKGROUND

Proteasome inhibition is a promising strategy for cancer therapy. Bortezomib, which primarily targets the chymotrypsin-like activity of PSMB5, has demonstrated efficacy in various tumors. However, there is variable sensitivity to bortezomib, which could be attributed, in part, to variations in the expression of proteasome subunits.

METHODS AND RESULTS

In this study, we investigated whether miR-383 affects the expression of proteasome subunits in osteosarcoma (OS) cells, and if so, whether OS cells display differential sensitivity to bortezomib concerning miR-383 expression. We detected a decreased miR-383 expression in OS cells and tissues. Then we found a negative correlation between the cytotoxicity of bortezomib and the expression level of the proteasome 20S core particle subunit β5 (PSMB5). Intriguingly, we identified PSMB5 as a direct target of miR-383. Increased expression of miR-383 resulted in decreased PSMB5 expression and increased sensitivity to bortezomib in OS cells.

CONCLUSIONS

In summary, our findings present the initial comprehensive analysis of the function of miR-383 in OS. The outcomes indicate that miR-383 may augment the anticancer effect of bortezomib through PSMB5 repression, offering a novel therapeutic approach in OS and a fresh pathway for proteasome regulation.

Multifaceted roles for BCL3 in cancer: a proto-oncogene comes of age

In the early 1990's a group of unrelated genes were identified from the sites of recurring translocations in B-cell lymphomas. Despite sharing the nomenclature 'Bcl', and an association with blood-borne cancer, these genes have unrelated functions. Of these genes, BCL2 is best known as a key cancer target involved in the regulation of caspases and other cell viability mechanisms. BCL3 on the other hand was originally identified as a non-canonical regulator of NF-kB transcription factor pathways - a signaling mechanism associated with important cell outcomes including many of the hallmarks of cancer. Most of the early investigations into BCL3 function have since focused on its role in NF-kB mediated cell proliferation, inflammation/immunity and cancer. However, recent evidence is coming to light that this protein directly interacts with and modulates a number of other signaling pathways including DNA damage repair, WNT/β-catenin, AKT, TGFβ/SMAD3 and STAT3 - all of which have key roles in cancer development, metastatic progression and treatment of solid tumours. Here we review the direct evidence demonstrating BCL3's central role in a transcriptional network of signaling pathways that modulate cancer biology and treatment response in a range of solid tumour types and propose common mechanisms of action of BCL3 which may be exploited in the future to target its oncogenic effects for patient benefit.

Emerging Therapeutic Targets and Drug Resistance Mechanisms in Immunotherapy of Hematological Malignancies

CAR-T cell therapy has revolutionized the treatment of hematological malignancies with high remission rates in the case of ALL and NHL. This therapy has some limitations such as long manufacturing periods, persistent restricted cell sources and high costs. Moreover, combination regimens increase the risk of immune-related adverse events, so the identification new therapeutic targets is important to minimize the risk of toxicities and to guide more effective approaches. Cancer cells employ several mechanisms to evade immunosurveillance, which causes resistance to immunotherapy; therefore, a very important therapeutic approach is to focus on the development of rational combinations of targeted therapies with non-overlapping toxicities. Recent progress in the development of new inhibitory clusters of differentiation (CDs), signaling pathway molecules, checkpoint inhibitors, and immunosuppressive cell subsets and factors in the tumor microenvironment (TME) has significantly improved anticancer responses. Novel strategies regarding combination immunotherapies with CAR-T cells are the most promising approach to cure cancer.

Novel Therapeutic Targets in Cancers

Cancer cells can arise in any organ of the body, and their cells of origin vary depending on the tissue type [...].

Fluorinated and N-Acryloyl-Modified 3,5-Di[(E)-benzylidene]piperidin-4-one Curcuminoids for the Treatment of Pancreatic Carcinoma

Pancreatic carcinoma is a cancer disease with high mortality. Thus, new and efficient treatments for this disease are badly needed. Curcumin has previously shown promising effects in pancreatic cancer patients; however, this natural compound suffers from inadequate efficacy and bioavailability, preventing its clinical approval. The synthetic curcuminoid EF24 was developed with activities superior to curcumin against various cancer types. In this study, a series of analogs of EF24 were investigated for anticancer effects on pancreatic carcinoma models. A distinct activity boost was achieved by straightforward N-acrylation of EF24 analogs, in particular, of compounds bearing 3-fluoro-4-methoxybenzylidene, 3,4-difluorobenzylidene, and 4-trifluoromethylbenzylidene moieties, while no improvement was seen for N-acryloyl-modified EF24. Apoptosis induction and suppression of phospho-STAT3 levels were determined, the latter corroborated by docking of active curcuminoids into STAT3. Hence, promising new clues for the development of efficient and superior curcuminoids as valuable treatment options for one of the most lethal cancer diseases were discovered in this study.