Drug sensitivity profile of minor KRAS mutations in colorectal cancer using mix culture assay: The effect of AMG-510, a novel KRAS G12C selective inhibitor, on colon cancer cells is markedly enhanced by the combined inhibition of MEK and BCL-XL.

Colorectal cancer with a Kirsten rat sarcoma 2 viral oncogene homolog (KRAS) gene mutation is considered to be resistant to anti-EGFR agents. G12D is the most common KRAS mutation in colorectal cancer, followed by G12V and G13D. According to clinical and basic research data, patients with colorectal cancer exhibiting G12D and G12V KRAS mutations are resistant to anti-EGFR agents; however, this is not true of G13D and other minor mutations, which are still not well understood. The current study focused on minor KRAS mutations (G12A, G12C, G12S, Q61H and A146T) and evaluated whether these were resistant to anti-EGFR antibodies using a mix culture assay. The results demonstrated that all KRAS mutations, including minor mutations, were resistant to two anti-EGFR agents: Cetuximab and panitumumab. The combined effect of MEK and BCL-XL inhibition on colorectal cancer cells with KRAS minor mutations were subsequently evaluated. The combined effect of MEK and BCL-XL inhibitors was confirmed in all KRAS minor mutations. The sensitivity of AMG510, a novel KRAS G12C selective inhibitor, was also assessed. The mix culture assay revealed that AMG510 selectively exerted an antitumor effect on colon cancer cells with a G12C KRAS mutation. The combination of MEK and BCL-XL inhibition markedly enhanced the effect of AMG510 in colon cancer cells. The current study suggested that AMG510 may have potential clinical use in combination with MEK and BCL-XL inhibitors in the treatment of patients with colorectal cancer exhibiting the G12C KRAS mutation.

Deubiquitinase JOSD2 stabilizes YAP/TAZ to promote cholangiocarcinoma progression.

Cholangiocarcinoma (CCA) has emerged as an intractable cancer with scanty therapeutic regimens. The aberrant activation of Yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (TAZ) are reported to be common in CCA patients. However, the underpinning mechanism remains poorly understood. Deubiquitinase (DUB) is regarded as a main orchestrator in maintaining protein homeostasis. Here, we identified Josephin domain-containing protein 2 (JOSD2) as an essential DUB of YAP/TAZ that sustained the protein level through cleavage of polyubiquitin chains in a deubiquitinase activity-dependent manner. The depletion of JOSD2 promoted YAP/TAZ proteasomal degradation and significantly impeded CCA proliferation in vitro and in vivo. Further analysis has highlighted the positive correlation between JOSD2 and YAP abundance in CCA patient samples. Collectively, this study uncovers the regulatory effects of JOSD2 on YAP/TAZ protein stabilities and profiles its contribution in CCA malignant progression, which may provide a potential intervention target for YAP/TAZ-related CCA patients.

Atypical Mesonephric Hyperplasia of the Uterus Harbors Pathogenic Mutation of Kirsten Rat Sarcoma 2 Viral Oncogene Homolog (KRAS) and Gain of Chromosome 1q.

BACKGROUND/AIM: Mesonephric carcinoma (MNC) is a rare but notable entity of the female genital tract. While many researchers have acknowledged and studied MNC, much remains unknown on the characteristics of mesonephric remnant (MNR) or hyperplasia (MNH). There has not been any study examining the molecular features of MNR and MNH so far. The aim of this study was to investigate the clinicopathological and molecular characteristics of ten uterine mesonephric lesions, including two MNRs without atypia, four MNHs without atypia, and three MNHs with atypia. MATERIALS AND METHODS: We reviewed the electronic medical records and all available slides of ten cases from multiple institutions. Targeted sequencing and array comparative genomic hybridization were performed. RESULTS: Three atypical MNHs displayed nuclear enlargement, mild-to-moderate nuclear pleomorphism, and nuclear membrane irregularity, and harbored pathogenic Kirsten rat sarcoma 2 viral oncogene homolograt sarcoma 2 viral oncogene homolog (KRAS) mutation. Two of those that co-existed with MNC harbored the same sequence alterations as each of their adjacent MNC. One of the three atypical MNHs harbored chromosome 1q gain. CONCLUSION: Atypical MNH is a potential premalignant lesion in which KRAS mutation and chromosome 1q gain play an important role in the early stage of mesonephric carcinogenesis.

Postrecurrence survival of surgically resected pulmonary adenocarcinoma patients according to EGFR and KRAS mutation status.

The aim of this study was to investigate the prognosis of pulmonary adenocarcinoma patients following postoperative recurrence, according to epidermal growth factor receptor (EGFR) and Kirsten rat sarcoma 2 viral oncogene homolog (KRAS) gene mutation status and recurrence site. In total 58 adenocarcinoma patients with recurrence following surgical resection were retrospectively evaluated between 2002 and 2011. The patients were divided into groups according to the presence or absence of EGFR and KRAS mutations and the clinicopathological characteristics, recurrence sites and postrecurrence survival were compared. EGFR and KRAS mutations were detected in 26 (45%) and 11 patients (19%), respectively. Initial recurrence was distant in 25 (43%), local in 17 (29%) and both distant and local in 16 cases (28%). In EGFR-mutant (EGFR+) cases, bilateral/contralateral lung recurrence was a frequent finding. EGFR+ cases exhibited significantly better outcomes compared to KRAS+ and EGFR-KRAS- (wild-type) cases. The 2-year post-recurrence survival rates were 81, 18 and 47% in EGFR+, KRAS+ and wild-type cases, respectively. The patients with distant organ recurrence exhibited significantly worse survival compared with those without distant recurrence in wild-type, but not in the EGFR+ cases or the entire cohort. Multivariate analysis revealed that EGFR mutations and a number of recurrent lesions were the only statistically significant independent predictors of postrecurrence prognosis. Our results indicated distinct survival differences in recurrent adenocarcinoma patients according to driver mutations. Patients with EGFR-mutated tumors exhibited increased survival, regardless of recurrence at distant sites, whereas patients with KRAS-mutated adenocarcinoma exhibited poor outcome following postoperative recurrence. Therefore, the assessment of driver mutations is essential for predicting postrecurrence survival following surgical resection.