CEACAM Gene Family Mutations Associated With Inherited Breast Cancer Risk - A Comparative Oncology Approach to Discovery

TWIST1 Upregulation Is a Potential Target for Reversing Resistance to the CDK4/6 Inhibitor in Metastatic Luminal Breast Cancer Cells

Cyclin-dependent kinase (CDK) 4/6 inhibitors have significantly improved progression-free survival in hormone-receptor-positive (HR+), human-epidermal-growth-factor-receptor-type-2-negative (HER2-) metastatic luminal breast cancer (mLBC). Several studies have shown that in patients with endocrine-sensitive or endocrine-resistant LBC, the addition of CDK4/6 inhibitors to endocrine therapy significantly prolongs progression-free survival. However, the percentage of patients who are unresponsive or refractory to these therapies is as high as 40%, and no reliable and reproducible biomarkers have been validated to select a priori responders or refractory patients. The selection of mutant clones in the target oncoprotein is the main cause of resistance. Other mechanisms such as oncogene amplification/overexpression or mutations in other pathways have been described in several models. In this study, we focused on palbociclib, a selective CDK4/6 inhibitor. We generated a human MCF-7 luminal breast cancer cell line that was able to survive and proliferate at different concentrations of palbociclib and also showed cross-resistance to abemaciclib. The resistant cell line was characterized via RNA sequencing and was found to strongly activate the epithelial-to-mesenchymal transition. Among the top deregulated genes, we found a dramatic downregulation of the CDK4 inhibitor CDKN2B and an upregulation of the TWIST1 transcription factor. TWIST1 was further validated as a target for the reversal of palbociclib resistance. This study provides new relevant information about the mechanisms of resistance to CDK4/6 inhibitors and suggests potential new markers for patients' follow-up care during treatment.

LncRNA ARAP1-AS1 contributes to lung adenocarcinoma development by targeting miR-8068 to upregulate CEACAM5

BACKGROUND

It has been discovered that lncRNA ARAP1-AS1 is upregulated and operates as a tumor promoter in many cancers. However, its pattern of expression and potential mechanism in lung adenocarcinoma (LUAD) is still unknown.

METHODS

The levels of lncRNA ARAP1-AS1, miR-8068, and CEACAM5 expressions in LUAD cell lines and tissues were assessed by conducting western blot and RT-qPCR analyses. MiR-8068's potential targeting relationships with lncRNA ARAP1-AS1 and CEACAM5 were ascertained by performing bioinformatics analysis. The interaction of lncRNA ARAP1-AS1 with miR-8068 was validated by means of by RIP and luciferase reporter experiments. CCK-8, cell adhesion, and Transwell migration experiments were conducted to study how lncRNA ARAP1-AS1 affects LUAD cell migration, adhesion, and proliferation. To confirm the function of lncRNA ARAP1-AS1 in vivo, a tumor formation experiment was executed.

RESULTS

An elevated expression of lncRNA ARAP1-AS1 was observed among the LUAD cells and tissues. The overexpression of lncRNA ARAP1-AS boosted cell proliferation, adhesion, and migration in LUAD and also favored in vivo tumor growth. MiR-8068 was found to be lncRNA ARAP1-AS1's target gene. MiR-8068 overexpression partially antagonized lncRNA ARAP1-AS1's promotive effect on proliferation, viability, and adhesion. Meanwhile CEACAM5 could alleviate the miR-8068-induced inhibition of tumor growth. The negative correlation of miR-8068 with lncRNA ARAP1-AS1 or CEACAM5 was also revealed.

CONCLUSION

To upregulate CEACAM5 expression lncRNA ARAP1-AS1 targeted miR-8068, thus promoting the progression of LUAD. This indicates that the lncRNA ARAP1-AS1/miR-8068/CEACAM5 axis has potential as a therapeutic target in LUAD treatment.

New Checkpoint Inhibitors on the Road: Targeting TIM-3 in Solid Tumors

PURPOSE OF REVIEW

Even though checkpoint inhibitors have become a recent milestone for the treatment of many different tumor types, eventually, most part of patients will develop resistance mechanisms and their disease will progress. New generations of checkpoint inhibitors, as the ones directed to TIM-3, are on research.

RECENT FINDINGS

TIM-3 expression has been associated with more advanced stages and shorter survival in several tumor types, due to its association with T-cell dysfunction, and has become an interesting target to explore. Early phase clinical trials with different anti-TIM-3 monoclonal antibodies have shown a safe toxicity profile, as cobolimab, LY3321367, or sabatolimab; however, the general antitumor activity remains to be determined and further investigations are needed. TIM-3 is implicated in resistance to immunotherapy due to its role in T cell exhaustion. However, the TIM-3 pathway is highly complex in terms of non-canonical signaling, broad expression by different immune cells and multiple ligands. Different anti-TIM-3 inhibitors are currently on research, either as monotherapy or in combination with other immunotherapies or chemotherapy, aiming to overcome resistance.

An investigation into the role of inherited CEACAM gene family variants and colorectal cancer risk

Objective

This study was designed to determine if CEACAM mutations are associated with inherited risk of colorectal cancer. Recently, protein-truncating mutations in the CEACAM gene family were associated with inherited breast cancer risk. That discovery, along with aberrant expression of CEACAM genes in colorectal cancer tumors and that colorectal cancer and breast cancer share many risk factors, including genetics, inspired our team to search for inherited CEACAM mutations in colorectal cancer cases. Specifically utilizing The Cancer Genome Atlas (TCGA) blood-derived whole-exome sequencing data from the colorectal cancer cohort, rare protein-truncating variants and missense variants were investigated through single variant and aggregation analyses in European American and African American cases and compared to ethnic-matched controls.

Results

A total of 34 and 14 different CEACAM variants were identified in European American and African American colorectal cancer cases, respectively. Nine missense variants were individually associated with risk, two in African Americans and seven in European Americans. No identified protein-truncating variants were associated with CRC risk in either ethnicity. Gene family and gene-specific aggregation analyses did not yield any significant results.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13104-022-05907-6.