Progress of Individualized Chemotherapy for Gastric Carcinoma Under the Guidance of Genetic Testing

LncRNA FAM13A-AS1, transcriptionally regulated by PHOX2B, modulates hepatocellular carcinoma chemoresistance via stabilizing PPARγ

Hepatocellular carcinoma (HCC) is a major global public health concern, with approximately 79 million new cases and 75 million HCC-related deaths occurring annually worldwide. Among the drugs, cisplatin (DDP) is considered a cornerstone and has been shown to significantly inhibit cancer progression. However, the mechanism underlying DDP-resistance in HCC remains unclear. This study aimed to identify a novel lncRNA. FAM13A Antisense RNA 1 (FAM13A-AS1), that promotes the proliferation of DDP-resistant HCC cells and to elucidate its downstream and upstream mechanisms in the progression of HCC DDP-resistance. Our results suggest that FAM13A-AS1 interacts directly with Peroxisome Proliferator Activated Receptor γ (PPARγ), stabilizing its protein through de-ubiquitination. Moreover, our findings indicate that Paired Like Homeobox 2B (PHOX2B) transcriptionally regulates the expression of FAM13A-AS1 in HCC cells. These results shed new light on the understanding of the progression of HCC DDP-resistance.

m6A Methyltransferase KIAA1429 Regulates the Cisplatin Sensitivity of Gastric Cancer Cells via Stabilizing FOXM1 mRNA

Simple Summary

N6-methyladenosine (m⁶A) is involved in the development of drug resistance in various cancer types. The role of N6-methyladenosine (m⁶A) methyltransferase, KIAA1429, in the resistance of gastric cancer to cisplatin is largely unknown. In this study, the KIAA1429 expression level as well as m⁶A content were found to be higher in cisplatin resistant gastric cancer cells, and KIAA1429 regulated the sensitivity of gastric cancer cells to cisplatin treatment. We then identified p65 as the regulator of KIAA1429 expression. Mechanistically, KIAA1429 regulated the sensitivity of gastric cancer cells to cisplatin by stabilizing FOXM1 mRNA via YTHDF1. The findings from this study suggest that KIAA1429 could be a therapeutic target of cisplatin resistance in gastric cancer.

Abstract

Although cisplatin is frequently used to treat gastric cancer, the resistance is the main obstacle for effective treatment. mRNA modification, N6-methyladenosine (m⁶A), is involved in the tumorigenesis of many types of cancer. As one of the largest m⁶A methyltransferase complex components, KIAA1429 bridges the catalytic m⁶A methyltransferase components, such as METTL3. In gastric cancer, KIAA1429 was reported to promote cell proliferation. However, whether KIAA1429 is involved in the resistance of gastric cancer to cisplatin remains unclear. Here, we generated cisplatin resistant gastric cancer cell lines, and compared the m⁶A content between resistant cells and wild type cells. The m⁶A content as well as KIAA1429 expression are higher in resistant cells. Interestingly, the expression of KIAA1429 was significantly increased after cisplatin treatment. We then used shRNA to knockdown KIAA1429 and found that resistant cells responded more to cisplatin treatment after KIAA1429 depletion, while overexpression of KIAA1429 decreased the sensitivity. Moreover, we identified a putative p65 binding site on the promoter area of KIAA1429 and ChIP assay confirmed the binding. p65 depletion decreased the expression of KIAA1429. YTHDF1 is the most abundant m⁶A “reader” that interacts with m⁶A modified mRNA. Mechanistically, YTHDF1 was recruited to the 3′-untranslated Region (3′-UTR) of transcriptional factor, FOXM1 by KIAA1429 and stabilized FOXM1 mRNA. More importantly, KIAA1429 knockdown increased the sensitivity of resistant cells to cisplatin in vivo. In conclusion, our results demonstrated that KIAA1429 facilitated cisplatin resistance by stabilizing FOXM1 mRNA in gastric cancer cells.

Chemosensitivity of gastric cancer: analysis of key pathogenic transcription factors

BACKGROUND

We aimed to screen the key pathogenic transcription factors of gastric cancer and analyzed the correlation between the expression of transcription factors and chemotherapy drugs in gastric cancer.

METHODS

Gastric cancer RNA sequencing data sets, single nucleotide polymorphism data sets, and corresponding clinical data sets were downloaded from The Cancer Genome Atlas, which is public data. The expression of transcription factors in gastric cancer and normal tissues was analyzed with R software. Pathway enrichment analysis of differentially expressed transcription factors was performed using the Kyoto Encyclopedia of Genes and Genomes database. Univariate Cox analysis was used to explore the correlation between the differential expression of transcription factors and prognosis. The interaction network among differentially expressed transcription factors was constructed using String database. Spearman test was used to explore the correlation between transcription factor mutation and gene expression. The Genomics of Drug Sensitivity in Cancer database was used to examine the relationship between the expression of transcription factors and chemotherapeutic drug sensitivity.

RESULTS

A total of 17 differentially expressed transcription factors were screened. The results indicated that CENPA, E2F1, EMX1, HOXA9, FOXM1, and MYBL2 were prognostic risk factors for gastric cancer patients (P<0.05), while RXRG and SOX4 were prognostic protective factors for gastric cancer patients (P<0.05). FDXM1 interacted with E2F7, MYBL2, E2F1, NCAPG, and SOX9. FOXM1 gene mutation was positively correlated with the expression level (P<0.05). Based on the median value of FOXM1, the patients were divided into high expression group and low expression group of FOXM1. There was no significant difference in IC50 of 5-fluorouracil between the FOXM1 high expression group and the FOXM1 low expression group (P>0.05). The IC50 of paclitaxel in the FOXM1 high expression group was higher than that in the FOXM1 low expression group (P<0.001). The expression of IC50 of cisplatin in the FOXM1 high expression group was higher than that in the FOXM1 low expression group (P<0.05).

CONCLUSIONS

FOXM1 was a highly expressed transcription factor in gastric cancer. High FOXM1 expression was associated with the resistance of gastric cancer patients to paclitaxel and cisplatin. Therefore, FOXM1 is a potential therapeutic target for gastric cancer.

CRISPR/Cas9-mediated knockout of SGLT1 inhibits proliferation and alters metabolism of gastric cancer cells

BACKGROUND

The roles played by sodium/glucose cotransporters 1 (SGLT1) that transport glucose in cells independent of extracellular glucose concentration in gastric cancer are unknown.

METHODS

The expression of SGLT1 in 75 primary gastric cancer and paired adjacent normal tissue specimens was determined. Also, the underlying mechanism of the altered SGLT1 expression and its impact on the proliferation of the gastric cancer cells and their metabolism were investigated.

RESULTS

SGLT1 expression was found to be positively associated with pT, pN, TNM staging, histological differentiation, and a worse overall survival. CRISPR/Cas9 mediated knockout of SGLT1 could inhibit proliferation of gastric cancer cells, promote their apoptosis, and could also alter the metabolism of gastric cancer cells. Mechanistically, the transcription activity of SGLT1 could be negatively regulated by p53.

CONCLUSIONS

Besides identifying the important role of SGLT1 in gastric cancer, the underlying regulation mechanism in play was also elucidated. These make SGLT1 a promising new molecular target for the design of novel therapeutic modalities to control gastric cancer.

Rutin attenuates Sorafenib-induced Chemoresistance and Autophagy in Hepatocellular Carcinoma by regulating BANCR/miRNA-590-5P/OLR1 Axis

Rutin, the main component of Potentilla discolor Bunge, was proven to exhibit anti-tumor properties. Sorafenib (SO) is conventionally used in chemotherapy against hepatocellular carcinoma (HCC), but acquired resistance developed during long-term therapy limits its benefits. This study aimed to explore the molecular mechanism of rutin in SO-induced autophagy and chemoresistance in HCC. Sixty-eight paired HCC patients who received the same chemotherapy treatment were obtained. We also established two SO resistance cell lines and then utilized high-throughput RNA sequencing to explore their long non-coding RNA (lncRNA) expression profiles. The target microRNA (miRNA) and downstream mRNA were also explored. Our results indicated that rutin treatment attenuates autophagy and BANCR expression in SO resistance cells. Transmission electron microscopy clearly showed a significantly decreased number of autophagosomes after rutin-treated HepG2/SO and HCCLM3/SO cells. BANCR knockdown promotes the sensitivity of SO resistance cells to SO. Further study found that BANCR acts as a molecular sponge of miR-590-5P to sequester miR-590-5P away from oxidized low-density lipoprotein receptor 1 (OLR1) in HCC cells. Furthermore, in vivo study demonstrated that rutin could inhibit autophagy through the BANCR/miRNA-590-5P/OLR1 axis. Our findings suggest that rutin could regulate autophagy by regulating BANCR/miRNA-590-5P/OLR1 axis.