Association of SMAD4 loss with drug resistance in clinical cancer patients: A systematic meta-analysis

Inhibition of EREG/ErbB/ERK by Astragaloside IV reversed taxol-resistance of non-small cell lung cancer through attenuation of stemness via TGFβ and Hedgehog signal pathway

PURPOSE

Taxol is the first-line chemo-drug for advanced non-small cell lung cancer (NSCLC), but it frequently causes acquired resistance, which leads to the failure of treatment. Therefore, it is critical to screen and characterize the mechanism of the taxol-resistance reversal agent that could re-sensitize the resistant cancer cells to chemo-drug.

METHOD

The cell viability, sphere-forming and xenografts assay were used to evaluate the ability of ASIV to reverse taxol-resistance. Immunohistochemistry, cytokine application, small-interfering RNA, small molecule inhibitors, and RNA-seq approaches were applied to characterize the molecular mechanism of inhibition of epiregulin (EREG) and downstream signaling by ASIV to reverse taxol-resistance.

RESULTS

ASIV reversed taxol resistance through suppression of the stemness-associated genes of spheres in NSCLC. The mechanism exploration revealed that ASIV promoted the K48-linked polyubiquitination of EREG along with degradation. Moreover, EREG could be triggered by chemo-drug treatment. Consequently, EREG bound to the ErbB receptor and activated the ERK signal to regulate the expression of the stemness-associated genes. Inhibition of EREG/ErbB/ERK could reverse the taxol-resistance by inhibiting the stemness-associated genes. Finally, it was observed that TGFβ and Hedgehog signaling were downstream of EREG/ErbB/ERK, which could be targeted using inhibitors to reverse the taxol resistance of NSCLC.

CONCLUSIONS

These findings revealed that inhibition of EREG by ASIV reversed taxol-resistance through suppression of the stemness of NSCLC via EREG/ErbB/ERK-TGFβ, Hedgehog axis.

From Crypts to Cancer: A Holistic Perspective on Colorectal Carcinogenesis and Therapeutic Strategies

Colorectal cancer (CRC) represents a significant global health burden, with high incidence and mortality rates worldwide. Recent progress in research highlights the distinct clinical and molecular characteristics of colon versus rectal cancers, underscoring tumor location's importance in treatment approaches. This article provides a comprehensive review of our current understanding of CRC epidemiology, risk factors, molecular pathogenesis, and management strategies. We also present the intricate cellular architecture of colonic crypts and their roles in intestinal homeostasis. Colorectal carcinogenesis multistep processes are also described, covering the conventional adenoma-carcinoma sequence, alternative serrated pathways, and the influential Vogelstein model, which proposes sequential APC, KRAS, and TP53 alterations as drivers. The consensus molecular CRC subtypes (CMS1-CMS4) are examined, shedding light on disease heterogeneity and personalized therapy implications.

Advanced renal pelvis carcinoma patient with an ERBB2 insertion mutation: a case report

The prognosis of renal pelvis cancer is poor and therapeutic options are limited, especially for patients with advanced disease. In this report, we present a case of advanced renal pelvis carcinoma in a male patient in his 60s, characterized by an activating mutation in ERBB2. Clinical evaluation resulted in a pathological diagnosis of renal pelvis carcinoma with liver metastasis. Immunohistochemistry staining results suggested that CK, P63, and PAX8 were positively expressed, while Sy, CK7, CK20, S100, PAX8, and HEP1 were negatively expressed. Furthermore, next-generation sequencing results showed an activating mutation in the ERBB2 gene. The patient initially received a trastuzumab-based combination therapy, which led to a significant reduction in ERBB2 mutation frequency and a stable condition after three treatment cycles. However, following continuous treatment for 4 months, the patient developed drug resistance that resulted in disease relapse. Subsequently, the patient received apatinib treatment, but the therapeutic response was not satisfactory. The patient's condition underwent rapid deterioration and he ultimately succumbed to the disease. This case underscores the potential benefit of trastuzumab for treating ERBB2-mutated advanced renal pelvis cancer, but further highlights that overcoming drug resistance remains a crucial challenge for long-term efficacy.

SMAD4 Positive Pancreatic Ductal Adenocarcinomas Are Associated with Better Outcomes in Patients Receiving FOLFIRINOX-Based Neoadjuvant Therapy

BACKGROUND

SMAD4 is inactivated in 50-55% of pancreatic ductal adenocarcinomas (PDACs). SMAD4 loss of expression has been described as a negative prognostic factor in PDAC associated with an increased rate of metastasis and resistance to therapy. However, the impact of SMAD4 inactivation in patients receiving neoadjuvant therapy (NAT) is not well characterized. The aim of our study was to investigate whether SMAD4 status is a prognostic and predictive factor in patients receiving NAT.

METHODS

We retrospectively analyzed 59 patients from a single center who underwent surgical resection for primary PDAC after NAT. SMAD4 nuclear expression was assessed by immunohistochemistry, and its relationship to clinicopathologic variables and survival parameters was evaluated. Interaction testing was performed between SMAD4 status and the type of NAT.

RESULTS

49.15% of patients presented loss of SMAD4. SMAD4 loss was associated with a higher positive lymph node ratio (p = 0.03), shorter progression-free survival (PFS) (p = 0.02), and metastasis-free survival (MFS) (p = 0.02), but it was not an independent prognostic biomarker in multivariate analysis. Interaction tests demonstrated that patients with SMAD4-positive tumors receiving FOLFIRINOX-based NAT showed the best outcome.

CONCLUSION

This study highlights the potential prognostic and predictive role of SMAD4 status in PDAC patients receiving FOLFIRINOX-based NAT.

Deregulated transcription factors and poor clinical outcomes in cancer patients

Transcription factors are a group of proteins, which possess DNA-binding domains, bind to DNA strands of promoters or enhancers, and initiate transcription of genes with cooperation of RNA polymerase and other co-factors. They play crucial roles in regulating transcription during embryogenesis and development. Their physiological status in different cell types is also important to maintain cellular homeostasis. Therefore, any deregulation of transcription factors will lead to the development of cancer cells and tumor progression. Based on their functions in cancer cells, transcription factors could be either oncogenic or tumor suppressive. Furthermore, transcription factors have been shown to modulate cancer stem cells, epithelial-mesenchymal transition (EMT) and drug response; therefore, measuring deregulated transcription factors is hypothesized to predict treatment outcomes of patients with cancers and targeting deregulated transcription factors could be an encouraging strategy for cancer therapy. Here, we summarize the current knowledge of major deregulated transcription factors and their effects on causing poor clinical outcome of patients with cancer. The information presented here will help to predict the prognosis and drug response and to design novel drugs and therapeutic strategies for the treatment of cancers by targeting deregulated transcription factors.

Epiregulin increases stemness-associated genes expression and promotes chemoresistance of non-small cell lung cancer via ERK signaling

Background

Chemoresistance often causes the failure of treatment and death of patients with advanced non-small-cell lung cancer. However, there is still no resistance genes signature and available enriched signaling derived from a comprehensive RNA-Seq data analysis of lung cancer patients that could act as a therapeutic target to re-sensitize the acquired resistant cancer cells to chemo-drugs. Hence, in this study, we aimed to identify the resistance signature for clinical lung cancer patients and explore the regulatory mechanism.

Method

Analysis of RNA-Seq data from clinical lung cancer patients was conducted in R studio to identify the resistance signature. The resistance signature was validated by survival time of lung cancer patients and qPCR in chemo-resistant cells. Cytokine application, small-interfering RNA and pharmacological inhibition approaches were applied to characterize the function and molecular mechanism of EREG and downstream signaling in chemoresistance regulation via stemness.

Results

The RTK and vitamin D signaling were enriched among resistance genes, where 6 genes were validated as resistance signature and associated with poor survival in patients. EREG/ERK signaling was activated by chemo-drugs in NSCLC cells. EREG protein promoted the NSCLC resistance to chemo-drugs by increasing stemness genes expression. Additionally, inhibition of EREG/ErbB had downregulated ERK signaling, resulting in decreased expression of stemness-associated genes and subsequently re-sensitized the resistant NSCLC cells and spheres to chemo-drugs.

Conclusions

These findings revealed 6 resistance genes signature and proved that EREG/ErbB regulated the stemness to maintain chemoresistance of NSCLC via ERK signaling. Therefore, targeting EREG/ErbB might significantly and effectively resolve the chemoresistance issue.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13287-022-02859-3.

The Role of SMAD4 Inactivation in Epithelial-Mesenchymal Plasticity of Pancreatic Ductal Adenocarcinoma: The Missing Link?

Simple Summary

Pancreatic ductal adenocarcinoma (PDAC) is currently one of the deadliest cancers. Despite the progress that has been made in the research of patient care and the understanding of pancreatic cancer, the survival rate remains mediocre. SMAD4, a tumor-suppressor gene, is specifically inactivated in 50–55% of pancreatic cancers. The role of SMAD4 protein loss in PDAC remains controversial, but seems to be associated with worse overall survival and metastasis. Here, we review the function of SMAD4 inactivation in the context of a specific biological process called epithelial–mesenchymal transition, as it has been increasingly associated with tumor formation, metastasis and resistance to therapy. By improving our understanding of these molecular mechanisms, we hope to find new targets for therapy and improve the care of patients with PDAC.

Abstract

Pancreatic ductal adenocarcinoma (PDAC) presents a five-year survival rate of 10% and its incidence increases over the years. It is, therefore, essential to improve our understanding of the molecular mechanisms that promote metastasis and chemoresistance in PDAC, which are the main causes of death in these patients. SMAD4 is inactivated in 50% of PDACs and its loss has been associated with worse overall survival and metastasis, although some controversy still exists. SMAD4 is the central signal transducer of the transforming growth factor-beta (TGF-beta) pathway, which is notably known to play a role in epithelial–mesenchymal transition (EMT). EMT is a biological process where epithelial cells lose their characteristics to acquire a spindle-cell phenotype and increased motility. EMT has been increasingly studied due to its potential implication in metastasis and therapy resistance. Recently, it has been suggested that cells undergo EMT transition through intermediary states, which is referred to as epithelial–mesenchymal plasticity (EMP). The intermediary states are characterized by enhanced aggressiveness and more efficient metastasis. Therefore, this review aims to summarize and analyze the current knowledge on SMAD4 loss in patients with PDAC and to investigate its potential role in EMP in order to better understand its function in PDAC carcinogenesis.