Roles of Necroptosis, Apoptosis, and Inflammation in Colorectal Carcinogenesis: A Longitudinal Human Study

AUTHORS

Timothy Su, Xiangzhu Zhu, Yong Li, Chang Yu, Xinqing Deng, Eugene Shubin, Lifang Hou, Jing Zhao, Lei Fan, Heping Zhang, Harvey J. Murff, Reid M. Ness, Martha J. Shrubsole, Qi Dai

ABSTRACT

Necroptosis triggers an inflammatory cascade associated with antimicrobial defense. No prospective human study has yet explored the role of necroptosis in colorectal cancer development. We conducted quantitative analysis of biomarkers for necroptosis [transient receptor potential cation channel subfamily M member 7 (TRPM7) and phosphorylated mixed lineage kinase domain-like protein], inflammation [cyclooxygenase-2 (COX-2)], apoptosis [BCL2-associated X (BAX) and terminal deoxynucleotidyl transferase dUTP nick end labeling], and cell proliferation (Ki67). This was done using tissue microarray biospecimens from the Cooperative Human Tissue Network and rectal biopsies from a longitudinal study within the Personalized Prevention of Colorectal Cancer Trial. In the human colorectal adenoma–carcinoma sequence, we observed an inverse expression trend between BAX and TRPM7; TRPM7 decreased from normal mucosa to small and large adenomas but significantly increased in early colorectal cancer stages (Ptrend = 0.004). It maintained high levels through all cancer stages. An increased COX-2 intensity in the epithelium was noted during tumorigenesis (Ptrend = 0.02) and was significantly associated with an elevated risk of metachronous polyps (odds ratio = 3.04; 95% confidence interval, 1.07–8.61; Ptrend = 0.02). The combined composite index scores of TRPM7 and COX-2 were strongly linked to 6- to 47-fold increased risks for metachronous adenoma/serrated polyps, whereas combined scores of phosphorylated mixed lineage kinase domain-like protein or TRPM7 with BAX were associated with an 11.5- or 13.3-fold elevated risk for metachronous serrated polyps. In conclusion, our findings suggest that COX-2 expression within normal-looking colorectal mucosa is significantly associated with an increased risk of metachronous colorectal polyp. Furthermore, our results propose the hypothesis that synergistic interactions among necroptosis, inflammation, and apoptosis could play a pivotal role in human colorectal tumorigenesis.

Prevention Relevance: Our findings suggest that COX-2 expression and combined scores of COX-2, TRPM7, and BAX hold promise for predicting the risk of metachronous polyps and could potentially serve as a tool for assessing the effectiveness of chemopreventive agents in preventing colorectal cancer during intervention trials.

Yes-associated protein plays oncogenic roles in human sporadic colorectal adenomas

AUTHORS

Lei Fan, Xingyi Guo, Mary K Washington, Jiajun Shi, Reid M Ness, Qi Liu, Wanqing Wen, Shuya Huang, Xiao Liu, Qiuyin Cai, Wei Zheng, Robert J Coffey, Martha J Shrubsole, Timothy Su

ABSTRACT

The role of Hippo-Yes-associated protein (YAP) in human colorectal cancer (CRC) presents contradictory results. We examined the function of YAP in the early stages of CRC by quantitatively measuring the expression of phospho-YAPS127 (p-YAP) and five APC-related proteins in 145 sporadic adenomas from the Tennessee Colorectal Polyp Study, conducting APC sequencing for 114 adenomas, and analyzing YAP-correlated cancer pathways using gene expression data from 326 adenomas obtained from Gene Expression Omnibus. The p-YAP expression was significantly correlated with YAP expression (r = 0.53, P < .0001) and nuclear β-catenin (r = 0.26, P = .0018) in adenoma tissues. Both p-YAP and nuclear β-catenin were associated with APC mutations (P = .05). A strong association was observed between p-YAP overexpression and advanced adenoma odds (OR = 12.62, 95% CI = 4.57–34.86, P trend < .001), which persisted after adjusting for covariates and biomarkers (OR = 12.31, 95% CI = 3.78–40.10, P trend < .0001). P-YAP exhibited a sensitivity of 77.4% and specificity of 78.2% in defining advanced versus nonadvanced adenomas. Additionally, synergistic interaction was noted between p-YAP positivity and nuclear β-catenin on advanced adenomas (OR = 16.82, 95% CI = 4.41–64.08, P < .0001). YAP-correlated genes were significantly enriched in autophagy, unfolded protein response, and sirtuin pathways showing predominantly pro-tumorigenic alterations. Collectively, YAP plays an oncogenic role in interacting with Wnt as well as other cancer pathways within human sporadic adenomas. P-YAP could be a potential biomarker for human high-risk sporadic adenomas.

Tumor-derived exosomal lncRNA-MIR193BHG promotes bone metastasis of breast cancer by targeting the miR-489-3p/DNMT3A signaling axis in osteoclasts

AUTHORS

Xiaoya Liu, Rui Ma, Feng Wei, Maihuan Wang, Yiwei Jiang, Peng Zheng, Zhen Cao

ABSTRACT

Background

Breast cancer exhibits high incidence and mortality among women, with distant metastasis, especially bone metastasis, being the leading cause of death. Despite advances in adjuvant therapies, bone metastasis remains a challenge for patient survival and quality of life. Exosomes, small vesicles capable of mediating intercellular communication, play a crucial role in tumor metastasis.

Results

This study investigated the role of tumor-derived exosomal long noncoding RNA (lncRNA)-MIR193BHG in breast cancer bone metastasis. LncRNA-MIR193BHG was delivered to osteoclasts via exosomes and promoted osteoclast formation and activity by targeting the miR-489-3p/DNA methyltransferase 3A (DNMT3A) signaling axis, thereby accelerating breast cancer-induced osteolysis. Knockdown experiments demonstrated that reducing the levels of exosomal lncRNA-MIR193BHG significantly inhibited osteoclast differentiation and bone resorption, which was confirmed both in vitro and in vivo. Additionally, mechanistic studies revealed that lncRNA-MIR193BHG acted as a competitive endogenous RNA (ceRNA) interacting with miR-489-3p, regulating DNMT3A expression and subsequently affecting osteoclast differentiation.

Conclusions

These findings suggest that lncRNA-MIR193BHG plays a critical regulatory role in breast cancer bone metastasis, and the lncRNA-MIR193BHG/miR-489-3p/DNMT3A signaling axis could be a potential target for the treatment of breast cancer bone metastasis. Future studies should further explore the broader applicability of this mechanism and its clinical feasibility.

CNSC-12. IMMUNOLOGICALLY TARGETING U1 MUTANT SHH MEDULLOBLASTOMA

AUTHORS

Michelle Kameda , Rong Zheng , Nabil Ahmed , Chonghui Cheng , Michael Taylor

ABSTRACT

OBJECTIVES

Medulloblastoma (MB) is the most common malignant pediatric brain tumor representing a significant burden of morbidity and mortality in the US. MB is comprised of four subgroups: Wnt, Shh, Group 3, and Group 4. Shh tumors represent 25% of cases and subdivides into Shh-beta and Shh-gamma, Shh-alpha, and Shh-delta. Half of Shh MB carry an identical somatic point mutation in a non-coding small nuclear RNA (snRNA) called U1 (r.3A>G) which is found in 97% of Shh-d tumors, and in most Shh-alpha tumors with TP53 mutations. Current therapies for patients with TP53 and U1 mutant Shh-alpha MB observe rare survivors, and adult Shh-delta patients continue to experience significant morbidity and mortality calling for urgent prioritization of these tumors for targeted therapy.

METHODS

Cryptic exons were identified in both Shh-delta U1 snRNA mutant samples and Shh-delta U1 wildtype (WT) samples using CryEx pipeline. In-house scripts were utilized for selecting for cryptic exons that are uniquely expressed in Shh-delta U1 snRNA mutant compared to wildtype (WT) samples.

RESULTS

Analyzing 180 Shh MB RNA-seq samples, we identified 23% Shh-alpha, no Shh-beta, 97% of Shh-delta and 3% Shh-gamma harbored the U1 mutation. The splicing landscape was then interrogated comparing Shh-delta U1 snRNA mutant samples to WT samples. Expressed exons were filtered to exclude known exons to identify novel or cryptic exons. To select for Shh-delta U1 snRNA mutant induced cryptic exons, CryEx arising from introns, not identified in Shh-delta U1 WT and included >10% of their inclusion rates measured by percent spliced in (PSI) in Shh-delta U1 snRNA mutant samples were filtered. Of the middle CryEx, we identified 43,188 that were U1 mutant induced. Further filtering for cell surface Middle CryEx, three of the 75 middle CryEx overlapped.

CONCLUSION

The PTCH1 neoantigen formed from the CryEx insertion translates a protein that is unique to the tumor cells (i.e., not in normal tissue) was identified as a juxtamembrane for therapeutic drug discovery.

Aberrant NSUN2-mediated m5C modification of exosomal LncRNA MALAT1 induced RANKL-mediated bone destruction in multiple myeloma

AUTHORS

Manya Yu, Zhiguo Cai, Jie Zhang, Yanyu Zhang, Jiaqi Fu, Xing Cui

ABSTRACT

The impact of exosome-mediated crosstalk between multiple myeloma (MM) cells and osteoclasts (OCs) on bone lesions remains to be investigated. Here, we identified NSUN2 and YBX1-mediated m5C modifications upregulated LncRNA MALAT1 expression in MM cells, which could be transported to OCs via exosomes and promote bone lesions. Methodologically, RNA-seq was carried out to detect the cargoes of exosomes. TRAP staining and WB were used to evaluate osteoclastogenesis in vitro. Micro-CT and bone histomorphometric analyses were performed to identify bone destruction in vivo. RNA pull-down, RIP, MeRIP, and luciferase reporter assays were used to test the interactions between molecules. The clinical features of MALAT1, NSUN2 and YBX1 were verified through public datasets and clinicopathological data analyses. Mechanistically, MALAT1 was the highest expressed lncRNA in U266 exosomes and could be transported to RAW264.7 cells. MALAT1 could enhance the differentiation of RAW264.7 cells into OCs by stimulating RANKL expression and its downstream AKT and MAPKs signaling pathways via a ceRNA mechanism. Additionally, MALAT1 could be modified by NSUN2, an m5C methyltransferase, which in turn stabilized MALAT1 through the “reader” YBX1. Clinical studies indicated a notable positive correlation between MALAT1, NSUN2, YBX1 levels and bone destruction features, as well as with RANKL expression.

Lung endothelium exploits susceptible tumor cell states to instruct metastatic latency

AUTHORS

Moritz Jakab, Ki Hong Lee, Alexey Uvarovskii, Svetlana Ovchinnikova, Shubhada R. Kulkarni, Sevinç Jakab, Till Rostalski, Carleen Spegg, Simon Anders & Hellmut G. Augustin

ABSTRACT

In metastasis, cancer cells travel around the circulation to colonize distant sites. Due to the rarity of these events, the immediate fates of metastasizing tumor cells (mTCs) are poorly understood while the role of the endothelium as a dissemination interface remains elusive. Using a newly developed combinatorial mTC enrichment approach, we provide a transcriptional blueprint of the early colonization process. Following their arrest at the metastatic site, mTCs were found to either proliferate intravascularly or extravasate, thereby establishing metastatic latency. Endothelial-derived angiocrine Wnt factors drive this bifurcation, instructing mTCs to follow the extravasation–latency route. Surprisingly, mTC responsiveness towards niche-derived Wnt was established at the epigenetic level, which predetermined tumor cell behavior. Whereas hypomethylation enabled high Wnt activity leading to metastatic latency, methylated mTCs exhibited low activity and proliferated intravascularly. Collectively the data identify the predetermined methylation status of disseminated tumor cells as a key regulator of mTC behavior in the metastatic niche.