Reduced Smad4 expression and DNA topoisomerase inhibitor chemosensitivity in non-small cell lung cancer

Clinicopathological and prognostic significance of SMAD4 in non-small cell lung cancer: A meta-analysis and database validation

BACKGROUND

The relationship between SMAD family member 4 (SMAD4) and the clinicopathological and prognostic significance of non-small cell lung cancer (NSCLC) patients is unclear. Our aim was to investigate the association between SMAD4 expression and clinicopathological parameters and NSCLC prognosis.

METHODS

We searched articles in databases from inception to July 2022 to retrieve literature related to SMAD4 expression and the clinicopathological and/or prognostic significance of NSCLC patients. Odds ratios (ORs), hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated. We evaluated the expression of SMAD4 and overall survival (OS) in NSCLC using the Kaplan-Meier plotter database.

RESULTS

Eight articles with 1461 NSCLC patients were included. SMAD4 expression was related to tumor differentiation (OR = 0.359, 95% CI: 0.238-0.543, P = .000), lymph node metastasis (OR = 0.469, 95% CI: 0.04-0.725, P = .001), tumor node metastasis stage (OR = 0.238, 95% CI: 0.156-0.362, P = .000) and good OS (HR = 0.592, 95% CI: 0.332-0.853, P = .000) in NSCLC. There was no significant association between SMAD4 expression and age (OR = 0.822, 95% CI: 0.515-1.312, P = .411) or sex (OR = 1.056, 95% CI: 0.675-1.653, P = .811). Furthermore, SMAD4 expression was lower in NSCLC, and a good prognosis in NSCLC (HR = 0.6, 95% CI = 0.51-0.72, P = 4.2 e-9) was shown to correlate with higher SMAD4 expression using the Kaplan-Meier Plotter database.

CONCLUSION

SMAD4 expression is lower in NSCLC and correlated with lymph node metastasis, tumor differentiation, tumor node metastasis stage and good OS for NSCLC patients.

Clinicopathological and Molecular Characteristics of Colorectal Signet Ring Cell Carcinoma: A Review

Colorectal signet ring cell carcinoma (SRCC) is a rare subtype of colorectal cancer (CRC) with unique characteristics. Due to the limited researches on it, a comprehensive and in-depth understanding of this subtype is still lacking. In this article, we summarize the clinicopathological features and molecular characteristics of colorectal SRCC based on a literature review. Clinically, SRCC has been associated with young age, proximal site preference, advanced tumor stage, high histological grade, high rate of lymph node involvement, frequent peritoneal metastasis, and a significantly poor prognosis. Regarding molecular characteristics, in SRCC, the mutation burden of the classic signaling pathways that include WNT/β-catenin, RAS/RAF/MAPK, and PI3K/AKT/mTOR signaling pathways are generally reduced. In contrast, some genes related to the “epithelial-mesenchymal transition (EMT) process” and the “stem cell properties”, including RNF43, CDH1, and SMAD4, as well as the related TGF-β signaling pathway have been observed more frequently altered in SRCC than in conventional adenocarcinoma (AC). In many studies but not in others, SRCC showed a higher frequency of BRAF mutation, microsatellite instability-high (MSI-H) and CpG island methylator phenotype (CIMP) positive status compared to AC. It has been proposed that colorectal SRCC consists of two subtypes, in which the MSI⁺/CIMP⁺/BRAF⁺/CD3⁺/PD-L1⁺ hypermethylated genotype is more common in the proximal colon, and may represent the potential candidate for immunotherapy. Understanding the special molecular mechanisms related to the aggressive biology of SRCC is of great importance, which may provide a theoretical basis for the development of more targeted and effective treatments for this refractory disease.

Preoperative clinical and tumor genomic features associated with pathologic lymph node metastasis in clinical stage I and II lung adenocarcinoma

While next-generation sequencing (NGS) is used to guide therapy in patients with metastatic lung adenocarcinoma (LUAD), use of NGS to determine pathologic LN metastasis prior to surgery has not been assessed. To bridge this knowledge gap, we performed NGS using MSK-IMPACT in 426 treatment-naive patients with clinical N2-negative LUAD. A multivariable logistic regression model that considered preoperative clinical and genomic variables was constructed. Most patients had cN0 disease (85%) with pN0, pN1, and pN2 rates of 80%, 11%, and 9%, respectively. Genes altered at higher rates in pN-positive than in pN-negative tumors were STK11 (p = 0.024), SMARCA4 (p = 0.006), and SMAD4 (p = 0.011). Fraction of genome altered (p = 0.037), copy number amplifications (p = 0.001), and whole-genome doubling (p = 0.028) were higher in pN-positive tumors. Multivariable analysis revealed solid tumor morphology, tumor SUVmax, clinical stage, SMARCA4 and SMAD4 alterations were independently associated with pathologic LN metastasis. Incorporation of clinical and tumor genomic features can identify patients at risk of pathologic LN metastasis; this may guide therapy decisions before surgical resection.

Neutrophils in Tumorigenesis: Missing Targets for Successful Next Generation Cancer Therapies?

Neutrophils—once considered as simple killers of pathogens and unexciting for cancer research—are now acknowledged for their role in the process of tumorigenesis. Neutrophils are recruited to the tumor microenvironment where they turn into tumor-associated neutrophils (TANs), and are able to initiate and promote tumor progression and metastasis. Conversely, anti-tumorigenic properties of neutrophils have been documented, highlighting the versatile nature and high pleiotropic plasticity of these polymorphonuclear leukocytes (PMN-L). Here, we dissect the ambivalent roles of TANs in cancer and focus on selected functional aspects that could be therapeutic targets. Indeed, the critical point of targeting TAN functions lies in the fact that an immunosuppressive state could be induced, resulting in unwanted side effects. A deeper knowledge of the mechanisms linked to diverse TAN functions in different cancer types is necessary to define appropriate therapeutic strategies that are able to induce and maintain an anti-tumor microenvironment.

SMAD4 mutation correlates with poor prognosis in non-small cell lung cancer

SMAD4 is an intracellular signaling mediator of the TGF-β pathway. Its mutation was commonly observed in gastrointestinal cancers, such as pancreatic cancer. The loss of SMAD4 on immunohistochemical staining is often used to suggest a pancreaticobiliary differentiation in evaluating a metastatic adenocarcinoma with unknown origin. However, the function and molecular mechanism of SMAD4 in non-small cell lung cancer (NSCLC) development are largely unknown. Thus, we studied the correlation between SMAD4 mutations and clinico-molecular features in the patients with NSCLC. We reported the frequencies and prognostic values of SMAD4 mutations in a Chinese NSCLC cohort using next-generation sequencing. The NSCLC cases from several public databases, including The Cancer Genome Atlas and others, were also used in this study to elucidate SMAD4-related molecular partners and mechanisms. Integrated bioinformatics analyses were conducted, such as analysis of Gene Ontology enrichment analysis, gene set enrichment analysis (GSEA), and survival analysis. Immunohistochemistry showed that the tissues harboring SMAD4 mutations tended to show SMAD4 deficiency or loss, while SMAD4 expression was significantly reduced at all stages of NSCLC cases. We found that reduced SMAD4 expression was more frequent in the patients with poor disease-free survival and resistance to platinum-based chemotherapy. SMAD4 mutation was an independent risk factor for the survival of NSCLC patients. The expression of SMAD4 was associated with that of SMAD2. The GSEA showed that SMAD4 might promote NSCLC progression by regulating proliferation, adhesion, and immune response. In conclusion, these data suggest that SMAD4 mutation or loss as well as reduced expression can be used to identify the NSCLC patients with poor survival and resistance to platinum-based chemotherapy. SMAD4 may be a predictive marker or therapeutic target in NSCLC. The source code and user's guide are freely available at Github: https://github.com/wangyue77-ab/smad4 .

Correlation between loss of Smad4 and clinical parameters of non-small cell lung cancer: an observational cohort study

Background

SMAD4 has been found to be inactivated to varying degrees in many types of cancer; the purpose of this study was to investigate the correlation between SMAD4 expression in non-small cell lung cancer (NSCLC) and clinical pathological parameters.

Methods

The serum concentration of SMAD4 was measured by enzyme-linked immunosorbent assay and its histological expression was quantified by immunohistochemistry.

Results

The serum concentration of Smad4 in patients with NSCLC was lower than that in benign lung disease patients and healthy individuals (P < 0.001) and its concentration was related to the histological classification, pathological differentiation, lymphatic metastasis and clinical stage of NSCLC. The sensitivity and specificity of serum Smad4 were 91.56% and 61.56% for screening NSCLC from healthy individuals and 84.55% and 60.36% for screening NSCLC from patients with benign lung disease. Logistic regression analysis showed that the degree of cell differentiation (P < 0.001), lymph node metastasis (P < 0.001) and clinical stage of NSCLC (P = 0.007) affected the expression of Smad4, and had a strong correlation with the expression of Smad4. The expression of Smad4 in NSCLC tissues was lower than that in normal lung tissues (P = 0.009) and its expression was related to the degree of tissue differentiation, lymph node metastasis and clinical stage (P < 0.05).

Conclusions

The downregulation or deletion of Smad4 is related to the malignant biological behavior of NSCLC and serum Smad4 could be considered as a potential molecular indicator for diagnosis and evaluation of NSCLC.

SMAD-6, -7 and -9 are potential molecular biomarkers for the prognosis in human lung cancer

SMADs, a family of proteins that function as signal transducers and transcriptional regulators to regulate various signaling pathways, including the transforming growth factor-β signaling pathway, are similar to the mothers against decapentaplegic family of genes and the sma gene family in Caenorhabditis elegans. SMADs generate context-dependent modulation by interacting with various sequence-specific transcription factors, such as E2F4/5, c-Fos, GATA3, YY1 and SRF, which have been found to serve a key role in lung carcinoma oncogenesis and progression. However, the prognostic values of the eight SMADs in lung cancer have not been fully understood. In the present study, the expression levels and survival data of SMADs in patients with lung carcinoma from the Oncomine, Gene Expression Profiling Interactive Analysis, Kaplan-Meier plotter and cBioPortal databases were downloaded and analyzed. It was found that the mRNA expression levels of SMAD-6, -7 and -9 were decreased in lung adenocarcinoma and squamous cell carcinoma compared with that in adjacent normal tissues, while there was no significant difference in SMADs 1-5. Survival analysis revealed that not only were low transcriptional levels of SMAD-6, -7 and -9 associated with low overall survival but they also had prognostic role for progression-free survival and post-progression survival (P<0.05) in patients with lung carcinoma. In conclusion, the present study demonstrated that SMAD-6, -7 and -9 are potential biomarkers for the prognosis of patients with lung carcinoma.

Development of syngeneic murine cell lines for use in immunocompetent orthotopic lung cancer models

BACKGROUND

Immunocompetent animal models are required to study tumor-host interactions, immunotherapy, and immunotherapeutic combinations, however the currently available immunocompetent lung cancer models have substantial limitations. While orthotopic models potentially help fill this gap, the utility of these models has been limited by the very small number of murine lung cancer cell lines capable of forming orthotopic tumors in immunocompetent C57BL/6 hosts.

METHODS

Primary lung tumors with specific genetic alterations were created in C57BL/6 background mice. These tumors were then passaged through other animals to increase tumorigenicity and select for the ability to grow in a non-self animal. Once tumors demonstrated growth in a non-self host, cell lines were established. Successful cell lines were evaluated for the ability to produce orthotopic lung tumors in immunocompetent hosts.

RESULTS

We produced six murine lung cancer lines capable of orthotopic lung tumor formation in immunocompetent C57BL/6 animals. These lines demonstrate the expected genetic alterations based on their primary tumor genetics.

CONCLUSIONS

These novel cell lines will be useful for evaluating tumor-host interactions, the impact of specific oncogenic alterations on the tumor microenvironment, and immunotherapeutic approaches. This method of generating murine lines capable of orthotopic growth can likely be applied to other tumors and will broaden the applicability of pre-clinical testing of immunotherapeutic treatment regimens.

Genomic alterations in signet ring and mucinous patterned colorectal carcinoma

BACKGROUND

The genetic alterations (GAs) in two specific histological subtypes of colorectal cancer (CRC), signet ring cell colorectal carcinoma (SRC) and mucinous colorectal carcinoma (MC), are not well known. In the present study, we employed next-generation sequencing to perform genetic profiling of SRC and MC, and compared the spectrum of GAs with the alterations found in conventional type colorectal cancer (CON).

MATERIALS AND METHODS

We selected 46 CRCs comprising 17 SRCs and mucinous carcinoma with signet ring cell component (SRCCs), 17 MCs, and 12 CONs with microsatellite stability or microsatellite instability-low. Deep sequencing was performed using a targeted cancer panel composed of 171 cancer-related genes. SMAD4 protein expression was evaluated by immunohistochemical staining.

RESULTS

We detected 108 mutations in 18 different genes. Overall, 2.34 GAs were detected per tumor (range, 0-14). The overall frequency of GA and alteration in targetable genes was less prevalent in SRC/SRCC compared to the frequency of alteration in MC/CON (p = 0.040 and p < 0.001, respectively). The GA profile of SRC/SRCC included TP53 (8/17, 47.1%), SMAD4 (5/17, 29.4%), KRAS (4/17.23.5%), APC (4/17.23.5%), PIK3CA, ATM, BRAF, and PIK3R1 (1/17, 5.9%, each). KRAS mutation was significantly less prevalent in SRC/SRCC compared to the number of KRAS mutations in MC (12/17, 70.6%) and CON (9/12, 75.0%) (p = 0.015 and 0.01, respectively). Compared to the 152 non-hypermutated CONs from TCGA database, SMAD4 alteration was predominant in SRC/SRCC (p = 0.045) with aberrant loss of SMAD4 expression (13/17, 76.5%) compared to the SMAD4 alterations in CON (5/15, 33.3%) (p = 0.031). Accordingly, KRAS (12/17, 70.6%), APC (6/17, 35.3%), SMAD4, TP53 (4/17, 23.5%, each), PIK3CA (3/17, 17.6%), AKT1, ATM, BRAF, EGFR, and EZH2 (1/17, 5.9%, each) were altered in MC. APC and TP53 mutations were less frequent in MC compared to those in TCGA-CON (p < 0.001 and 0.003, respectively) whereas KRAS mutation was prevalent (p = 0.041).

CONCLUSION

Alterations of known cancer associated genes and targetable genes in SRC/SRCC are infrequent. The profile of GAs in SRC/SRCC and MC differs from the GA profile of CON. Specifically, SMAD4 mutation and loss of SMAD4 expression is frequently found in SRC/SRCC. The genetic profiles revealed in the present study may aid in developing precision medicine for CRC treatment based on histological subtype.

Lessons learned from SMAD4 loss in squamous cell carcinomas

SMAD4 is a potent tumor suppressor and a central mediator of the TGFß signaling pathway. SMAD4 genetic loss is frequent in squamous cell carcinomas (SCCs). Reports of SMAD4 expression in SCCs vary significantly possibly due to inter-tumor heterogeneity or technical reasons. SMAD4 loss is an initiation event for SCCs. In tumor epithelial cells, SMAD4 loss causes increased proliferation, decreased apoptosis, and "Brca-like" genomic instability associated with DNA repair defects. SMAD4 loss also plays a role in the expansion of cancer stem cells. Epithelial SMAD4 loss causes overexpression of TGFß that is released into the tumor microenvironment and contributes to SCC progression through proinflammatory and immune evasive mechanisms. SMAD4 loss, while not a direct therapeutic target, is associated with multiple targetable pathways that require further therapeutic studies. Altogether, SMAD4 loss is a potential biomarker in SCCs that should be further studied for its values in prognostic and therapeutic predictions. Such information will potentially guide future biomarker-driven clinical trial designs and improve SCC patient outcomes.