YAP/STAT3 promotes the immune escape of larynx carcinoma by activating VEGFR1-TGFβ signaling to facilitate PD-L1 expression in M2-like TAMs

Metformin as an immunomodulatory agent in enhancing head and neck squamous cell carcinoma therapies

Head and neck squamous cell carcinoma (HNSCC) remains a significant clinical challenge due to its aggressive behavior and poor prognosis, making the development of novel therapeutics with enhanced efficacy and minimal side effects critical. Metformin, a widely used antidiabetic agent, has recently emerged as a potential adjunctive therapy for HNSCC, exhibiting both direct anti-tumor and immunomodulatory effects. This review comprehensively explores the multifaceted role of metformin in shaping the tumor immune microenvironment within HNSCC. We emphasize its pivotal role in modulating immune cell populations and its potential for synergistic action with immunotherapeutic strategies. Furthermore, we address the current challenges associated with optimizing dosing regimens, identifying predictive biomarkers, and integrating metformin with immunotherapy. By dissecting these aspects, this review aims to pave the way for the development of personalized HNSCC treatment strategies that fully exploit the therapeutic potential of metformin.

Cyclic increase in the histamine receptor H1-ADAM9-Snail/Slug axis as a potential therapeutic target for EMT-mediated progression of oral squamous cell carcinoma

The intricate involvement of the histaminergic system, encompassing histamine and histamine receptors, in the progression of diverse neoplasias has attracted considerable scrutiny. Histamine receptor H1 (HRH1) was reported to be overexpressed in several cancer types, but its specific functional implications in oral squamous cell carcinoma (OSCC) predominantly remain unexplored. Our findings indicate that dysregulated high levels of HRH1 were correlated with lymph node (LN) metastasis and poor prognoses in OSCC patients. We identified a disintegrin and metalloprotease 9 (ADAM9) as a critical downstream target of HRH1, promoting protumorigenic and prometastatic characteristics both in vitro and in vivo. Molecular investigations revealed that the cyclic increase in the HRH1-ADAM9-Snail/Slug axis promoted progression of the epithelial-to-mesenchymal transition (EMT). Clinical analyses demonstrated significant correlations of HRH1 expression with ADAM9 and with EMT-related markers, with elevated ADAM9 also associated with LN metastasis in OSCC patients. Regarding therapeutic aspects, we discovered that activated STAT3 acts as a compensatory pathway for the long-term HRH1 signaling blockade in OSCC cells. Combining inhibition of HRH1 and STAT3 using their respective inhibitors or short hairpin (sh)RNAs enhanced the tumor-suppressive effects compared to HRH1 inhibition/depletion alone in OSCC cells and a xenograft model. In summary, HRH1 has emerged as a valuable biomarker for predicting OSCC progression, and combined targeting of HRH1 and STAT3 may represent a promising strategy for preventing OSCC progression.

Phytochemicals and their Nanoformulations for Overcoming Drug Resistance in Head and Neck Squamous Cell Carcinoma

BACKGROUND

Drug resistance remains a significant challenge in the treatment of head and neck squamous cell carcinoma (HNSCC), leading to therapeutic failure and poor patient prognosis. Numerous mechanisms, including drug efflux pumps, altered tumor microenvironment (TME), and dysregulated cell death pathways, contribute to the development of resistance against conventional chemotherapeutic agents, immunotherapy, and targeted therapies. As resistance to traditional treatments continues to emerge, there is an urgent need for innovative therapeutic strategies to overcome these challenges. Phytochemicals are naturally occurring bioactive compounds and have demonstrated remarkable potential in targeting multiple resistance mechanisms simultaneously.

METHOD

This review comprehensively overviews the current understanding of drug resistance mechanisms in HNSCC and explores innovative strategies utilizing phytochemicals and their nanoformulations to overcome these resistance mechanisms, with a particular focus on recent developments and future perspectives in this field.

RESULTS AND DISCUSSION

Phytochemicals with anticancer properties include a wide range of herbal-derived molecules such as flavonoids, stilbenes, curcuminoids, alkaloids, traditional Chinese medicine, and others. These compounds can modulate ATP-binding cassette transporters, reverse epithelial-to-mesenchymal transition (EMT), target cancer stem cells (CSCs), and regulate various signaling pathways involved in drug resistance. The integration of phytochemicals into advanced nanoformulation systems has also shown a remarkable improvement in enhancing their bioavailability, stability, and targeted delivery to the TME, potentially improving their therapeutic efficacy. Furthermore, the combination of phytochemicals with conventional chemotherapeutic agents, targeted molecular therapy, and immune checkpoint inhibitors (ICIs) has exhibited synergistic effects, offering a promising approach to restoring drug sensitivity in resistant HNSCC cells.

CONCLUSION

Phytochemicals and their nanoformulations may improve response of HNSCC to therapy by alleviating drug resistance.

Exosomal AC068768.1 enhances the proliferation, migration, and invasion of laryngeal squamous cell carcinoma through miR-139-5p/NOTCH1 axis

Objective

Long non-coding RNAs (lncRNAs) are closely associated with the pathogenesis of laryngeal squamous cell carcinoma (LSCC). This study aimed to investigate the roles of AC068768.1 in LSCC.

Methods

Exosomes were extracted by ultracentrifugation and identified by transmission electron microscopy (TEM) assay. The expression levels of mRNA and miRNA were determined by real-time quantitative polymerase chain reaction (RT-qPCR). Cellular functions were assesses through immunofluorescence, flow cytometry, colony formation, wound healing and transwell assays. Chromatin immunoprecipitation (ChIP) and luciferase assays were conducted to verify the binding of AC068768.1 by signal transducer and activator of transcription 3 (STAT3). Xenograft assays were performed to confirm the roles of AC068768.1 in LSCC, and hematoxylin-eosin (HE) staining was applied for histological analysis.

Results

LSCC cell-derived exosomes induced M2-like tumor-associated macrophages (TAM2) polarization, which promoted the proliferation, migration, and invasion of LSCCs. Knockdown of exosomal AC068768.1 inhibited M2 polarization and suppressed LSCC aggressiveness both in vitro and in vivo. Moreover, AC068768.1 sponged miR-139-5p, inducing the upregulation of neurogenic locus notch homolog protein 1 (NOTCH1). LSCCs adapted to TAM2 polarization in the tumor microenvironment via AC068768.1-mediated activation of the NOTCH1 pathway. Additionally, NOTCH1 activated STAT3.

Conclusion

The AC068768.1/miR-139-5p/NOTCH1/STAT3 axis promotes the metastasis of LSCC. This finding may provide a novel target for LSCC therapy.

Colorectal cancer tumor cell-derived exosomal miR-203a-3p promotes CRC metastasis by targeting PTEN-induced macrophage polarization

(1) Background: Tumor-associated macrophages (TAMs) are important immunocytes associated with liver metastasis of colorectal cancer (CRLM). However, the molecular processes underpinning the interaction between the TME and the tumour-derived exosomal miRNAs in CRLM are not being fully understood; (2) Methods: Transmission electron microscopy was utilized to confirm the existence of exosomes after differential ultracentrifugation. To determine the roles of exosomal miR-203a-3p, an in vivo and in vitro investigation was conducted. The mechanism by which exosomal miR-203a-3p governs the interaction between CRC cells and M2 macrophages was investigated using a dual-luciferase reporter assay, western blot, and other techniques; (3) Results: Overexpression of miR-203a-3p was associated with poor prognosis and liver metastasis in CRC patients. Exosomal miR-203a-3p was upregulated in the plasma of CRC patients and highly metastatic CRC cells HCT116, and it could be transported to macrophages via exosomes. Exosomal miR-203a-3p induced M2 polarization of macrophages by controlling PTEN and activating the PI3K/Akt signaling pathway. M2-polarized macrophages secreted the CXCL12, which increased cancer metastasis and resulted in pre-metastatic niches in CRLM by CXCL12/CXCR4/NF-κB signaling pathway. Co-culture of macrophages with miR-203a-3p-transfected or exosome-treated cells increased the ability of HCT116 cells to metastasize both in vitro and in vivo; (4) Conclusions: Exosomes produced by highly metastatic CRC cells and rich in miR-203a-3p may target PTEN and alter the TME, promoting liver metastasis in CRC patients. These findings offer fresh understanding of the liver metastatic process in CRC.

YAP/STAT3 inhibited CD8+ T cells activity in the breast cancer immune microenvironment by inducing M2 polarization of tumor-associated macrophages

BACKGROUND

Breast cancer (BC) is the leading cause of cancer-related death among women. One of the hallmarks of cancer is sustained angiogenesis. YAP/STAT3 may promote angiogenesis and driving BC progression. This study aimed to investigate how YAP/STAT3 affects the immune microenvironment in BC and understand the underlying mechanism.

METHODS

To establish a tumor-associated macrophages (TAMs) model, macrophages were cultured in the 4T1 cell culture medium. A BC mouse model was created by injecting 4T1 cells. The expression of YAP, STAT3, p-STAT3, VEGF, VEGFR-2, and PD-L1 was analyzed using immunofluorescence, western blotting, and quantitative real-time PCR. Flow cytometry was used to identify M1 and M2 macrophages, CD4+ T, CD8+ T, and Treg cells. Levels of iNOS, IL-12, IL-10, TGF-β, Arg-1, and CCL-22 were measured using enzyme-linked immunosorbent assay. Co-IP was used to verify whether YAP binds to STAT3. Hematoxylin-eosin staining was used to observe tumor morphology. Cell counting kit-8 was selected to detect T-cell proliferation.

RESULTS

YAP, STAT3, P-STAT3, VEGF, VEGFR-2, and PD-L1 were highly expressed in BC tissues. The M2/M1 macrophages ratio increased in the TAMs group compared with the control group. Inhibiting of YAP and STAT3 decreased the M2/M1 macrophages ratio. YAP was found to bind with STAT3. T-cell proliferation was enhanced after YAP inhibition, and overexpression of STAT3 reversed the regulation of YAP on T-cell proliferation. In animal studies, inhibiting YAP inhibited tumor weight and volume development. After YAP inhibition, inflammatory infiltration, M2/M1 macrophage ratio, and Treg cell ratio declined, while CD8+ and CD4+ T-cell ratio increased.

CONCLUSION

In conclusion, this study suggested inhibition of YAP/STAT3 reversed M2 polarization of TAMs and suppressed CD8+ T-cell activity in the BC immune microenvironment. These findings open up new avenues for the development of innovative therapies in the treatment of BC.

YAP Activates STAT3 Signalling to Promote Colonic Epithelial Cell Proliferation in DSS-Induced Colitis and Colitis Associated Cancer

BACKGROUND AND AIMS

Yes-associated protein (YAP) is a key transcriptional coactivator of cell proliferation and differentiation. In this study, we sought to identify the roles of YAP in colonic epithelial regeneration and tumourigenesis.

METHODS

Murine DSS-induced colitis and YAP overexpression models were constructed via lentiviral intraperitoneal injection. Stable YAP-overexpressing cells, protein immunoprecipitation, and ChIP were used to deeply explore the molecular mechanism.

RESULTS

We found that the expression of YAP was dramatically diminished in the colonic crypts during the acute colitis phase, while YAP was strikingly enhanced to initiate tissue repair after DSS withdrawal. Overexpressing YAP in mice drastically accelerated epithelial regeneration, presenting with more intact structural integrity and reduced inflammatory cell infiltration in the mucosa. Further mechanistic studies showed that the expression of YAP in the nucleus was significantly increased by 2 h post-DSS removal, accompanied by upregulated protein levels of activated STAT3. Overexpression of YAP (YAP^WT) elevated the expression of activated STAT3 and its transcriptional targets and strengthened the proliferation and "wound healing" ability of colonic cells. However, these effects were reversed when STAT3 was silenced in YAP^WT cells. Moreover, YAP could directly interact with STAT3 in the nucleus, and c-Myc and CyclinD1 were the transcriptional targets. Finally, during colitis-associated cancer (CAC), YAP^WT promoted the progression of CAC, while the phosphomimetic YAP downregulated the expression of STAT3 and inhibited the development and progression of CAC.

CONCLUSION

YAP activates STAT3 signalling to facilitate mucosal regeneration after DSS-induced colitis. However, excessive YAP activation in the colonic epithelium promotes CAC development.