Exploration of Kras Mutations and Their Potential for Being a Target Molecule in Cancer Chemotherapy

The Rat sarcoma virus (RAS) family of proteins, which includes the Kristen Rat sarcoma virus (KRAS), is linked to nearly one-fourth of all human cancers. KRAS mutations, in particular, are associated with Non-Small Cell Lung Carcinoma (NSCLC), colorectal cancer, adenocarcinomas, ovarian carcinoma, and endometrial tumors. KRAS activates 80 different signaling pathways, including Mitogen-activated protein kinases (MAPK) and Phosphoinositide 3-kinase (PI3K), and up-regulates transcription factors such as ETS like Protein (ELK), Jun Proto-Oncogene (JUN), and Myelocytomatosis (MYC), which are involved in cell differentiation, proliferation, transformation, and survival. KRAS mutations are also known to cause autocrine function, which further exacerbates the situation. In NSCLC, KRAS mutations have a strong positive correlation with the disease, particularly in patients with a smoking history. In pancreatic cancer, KRAS mutations are a dominant pathological basis, with most mutations being G12D, G12V, G13D, G13C, G13S, and G13R. These mutations serve as initial markers in tumorigenesis and are associated with poor prognosis and high mortality rates. In colorectal cancer, KRAS mutations contribute to 4/5 of cases, with cellular mechanisms involving the MAPK pathway, which resists anti-epidermal growth factor antibodies. In Low-grade Serous Ovarian Cancer (LGSOC), KRAS mutations are associated with altered signaling in the MAPK pathway and drug resistance. However, treatments such as Selumetinib, a down regulator of RAS/Rapidly Accelerated Fibrosarcoma (RAF)/Mitogen-activated protein kinase (MEK) pathways, and a combination of trametinib and buparlisib have shown promise in managing LGSOC when diagnosed early through KRAS mutation markers. Although KRAS mutations are commonly associated with many types of cancer, their use in clinical practice is limited due to the lack of accurate methods to identify them. It is needed to further isolate the KRAS mutation products and correlate the cancer-causing genes to make it a promising approach for cancer chemotherapy.

Feasibility of MRI Radiomics for Predicting KRAS Mutation in Rectal Cancer

The mutation status of KRAS is a significant biomarker in the prognosis of rectal cancer.This study investigated the feasibility of MRI-based radiomics in predicting the mutation status of KRAS with a composite index which could be an important criterion for KRAS mutation in clinical practice.In this retrospective study,a total of 127 patients with rectal cancer were enrolled.The 3D Slicer was used to extract the radiomics features from the MRI images,and sparse support vector machine(SVM)with linear kernel was applied for feature reduction.The radiomics classifier for predicting the KRAS status was then constructed by Linear Discriminant Analysis(LDA)and its performance was evaluated.The composite index was determined with LDA model.Out of 127 rectal cancer subjects,there were 44 KRAS mutation cases and 83 wild cases.A total of 104 radiomics features were extracted,54 features were filtered by linear SVM with L1-norm regularization and 6 features that had no significant correlations within them were finally selected.The radiomics classifier constructed using the 6 features featured an AUC value of 0.669(specificity:0.506;sensitivity:0.773)with LDA.Furthermore,the composite index(Radscore)had statistically significant difference between the KRAS mutation and wild groups.It is suggested that the MRI-based radiomics has the potential in predicting the KRAS status in patients with rectal cancer,which may enhance the diagnostic value of MRI in rectal cancer.

Advances in KRAS mutation inhibition in metastatic colorectal cancer

KRAS is the most frequently mutated oncogene in human malignancies,observed in approximately two in five colorectal cancers(CRC).KRAS mutations were historically considered“undruggable”ten years ago and associated with resistance to EGFR targeted therapy.The success of finding allele-specific covalent KRASG12C inhibitors recently has made markedly breakthrough in KRAS targeted therapy,and has accelerated the discovery of agents targeting other KRAS mutants,such as G12D and G12V.Evidence in preclinical and clinical settings has proved excellent efficacy of several inhibitors in KRAS mutant CRC.Sotorasib and Adagrasib are currently changing the treatment paradigm for patients with metastatic CRC harboring KRASG12C mutation.The phenomenon that KRASG12C inhibition shows inferior efficacy in patients with CRC compared with non-small cell lung cancer has been observed in clinic due to drug resistance,and combination strategies to overcome the resistance are now being investigated in clinical trials.Here,we review the development of KRAS targeted treatment in CRC,mechanisms of resistance and potential combination strategies to improve efficacy.

Immune status and combined immunotherapy progression in Kirsten rat sarcoma viral oncogene homolog(KRAS)-mutant tumors

Kirsten rat sarcoma viral oncogene homolog(KRAS)is the most frequently mutated oncogene,occurring in various tumor types.Despite extensive efforts over the past 40 years to develop inhibitors targeting KRAS mutations,resistance to these inhibitors has eventually emerged.A more precise understanding of KRAS mutations and the mechanism of resistance development is essential for creating novel inhibitors that target specifically KRAS mutations and can delay or overcome resistance.Immunotherapy has developed rapidly in recent years,and in-depth dissection of the tumor immune microenvironment has led researchers to shift their focus to patients with KRAS mutations,finding that immune factors play an essential role in KRAS-mutant(KRAS-Mut)tumor therapy and targeted drug resistance.Breakthroughs and transitions from targeted therapy to immunotherapy have provided new hope for treating refractory patients.Here,we reviewed KRAS mutation-targeted treatment strategies and resistance issues,focusing on our in-depth exploration of the specific immune status of patients with KRAS mutations and the impact of body immunity following KRAS inhibition.We aimed to guide innovative approaches combining RAS inhibition with immunotherapy,review advances in preclinical and clinical stages,and discuss challenges and future directions.

Transglutaminase 2 serves as a pathogenic hub gene of KRAS mutant colon cancer based on integrated analysis

BACKGROUND Colon cancer is acknowledged as one of the most common malignancies worldwide,ranking third in United States regarding incidence and mortality.Notably,approximately 40%of colon cancer cases harbor oncogenic KRAS mutations,resulting in the continuous activation of epidermal growth factor receptor signaling.AIM To investigate the key pathogenic genes in KRAS mutant colon cancer holds considerable importance.METHODS Weighted gene co-expression network analysis,in combination with additional bioinformatics analysis,were conducted to screen the key factors driving the progression of KRAS mutant colon cancer.Meanwhile,various in vitro experiments were also conducted to explore the biological function of transglutaminase 2(TGM2).RESULTS Integrated analysis demonstrated that TGM2 acted as an independent prognostic factor for progression-free survival.Immunohistochemical analysis on tissue microarrays revealed that TGM2 was associated with an elevated probability of perineural invasion in patients with KRAS mutant colon cancer.Additionally,biological roles of the key gene TGM2 was also assessed,suggesting that the downregulation of TGM2 attenuated the proliferation,invasion,and migration of the KRAS mutant colon cancer cell line.CONCLUSION This study underscores the potential significance of TGM2 in the progression of KRAS mutant colon cancer.This insight not only offers a theoretical foundation for therapeutic approaches but also highlights the need for additional clinical trials and fundamental research to support our preliminary findings.

BRAF and KRAS mutations in metastatic colorectal cancer:future perspectives for personalized therapy

Colorectal cancer(CRC)is one of the most commonly diagnosed cancers worldwide and 30%of patients with CRC experience metastasis.Patients with metastatic colorectal cancer(mCRC)have a 5-year overall survival rate of<10%.V-raf murine sarcoma viral oncogene homolog B1(BRAF)and V-Ki-ras2 Kirsten ratsarcoma viral oncogene homolog(KRAS)mutations are mostly studied in mCRC,as clinical trials found that first-line chemotherapy with anti-epidermal growth factor receptor agent confers limited efficacy for mCRC.Treatment decisions for early-stage mCRC do not consider BRAF or KRAS mutations,given the dramatically poor prognosis conferred by these mutations in clinical trials.Thus,it is necessary to identify patients with mCRC harboring BRAF or KRAS mutations to formulate rational therapeutic strategies to improve prognosis and survival.BRAF and KRAS mutations occur in10%and44%of patients with mCRC,respectively.Although the survival rate of patients with mCRC has improved in recent years,the response and prognosis of patients with the aforementioned mutations are still poor.There is a substantial unmet need for prospective personalized therapies for patients with BRAF-or KRAS-mutant mCRC.In this review,we focus on BRAF and KRAS mutations to understand the mechanisms underlying resistance and improving the response rate,outcomes,and prognosis of patients with mCRC bearing these mutations and to discuss prospective personalized therapies for BRAF-and KRAS-mutant mCRC.

Clinicopathological Features and Prognostic Value of KRAS/NRAS/BRAF Mutations in Colorectal Cancer Patients of Central China

The incidence of colorectal cancer(CRC)is increasing in China,with high mortality.Here,we aimed to evaluate the latest clinicopathological features and prognostic value of the KRAS/NRAS/BRAF mutation status in CRC patients in Central China.The clinical data of 1549 CRC patients with stage I-IV disease diagnosed at Union Hospital,Tongji Medical College of Huazhong University of Science and Technology from 2015 to 2017 were collected and analyzed retrospectively.KRAS/NRAS/BRAF mutations were detected by real-time quantitative polymerase chain reaction(q-PCR)in 410 CRC patients,with mutation frequencies of KRAS,NRAS and BRAF of 47.56%,2.93%and 4.15%,respectively.The gene mutation status and clinicopathological characteristics of 410 patients with CRC who underwent qPCR were analyzed.The KRAS and BRAF gene mutations were related to the pathological differentiation and number of metastatic lymph nodes.The BRAF gene mutation was also associated with cancer thrombosis in blood vessels.Cox regression analysis showed that there was no statistically significant difference in the overall survival(OS)between patients with KRAS,NRAS mutants and wild-type CRC patients,while the BRAF gene mutation was negatively correlated with the OS rate of CRC patients.It is suggested that the BRAF gene mutation may be an independent risk factor for the prognosis of CRC.

Efficacy of rigosertib, a small molecular RAS signaling disrupter for the treatment of KRAS-mutant colorectal cancer

Objective:Mutant KRAS,the principal isoform of RAS,plays a pivotal role in the oncogenesis of colorectal cancer by constitutively activating the RAF/MEK/ERK and PI3K/AKT pathways.Effective targeted therapies are urgently needed.We investigated whether rigosertib,a benzyl styryl sulfone RAS signaling disruptor,could selectively kill KRAS-mutant colorectal cancer cells.Methods:CCK-8 was used to determine the cell viability.Patient-derived tumor and cancer cell xenograft models were used to detect the inhibitory efficacy of rigosertib.Flow cytometry was used to evaluate the apoptosis and cell cycle progression.Apoptosis and cell cycle arrest markers were detected by Western blot.DCFH-DA was used to determine the reactive oxygen species.Immunohistochemistry staining and Western blot were performed to characterize RAS signaling markers in colorectal cancer tissues and cells.Results:Rigosertib(RGS)exhibited a cytotoxic effect against colorectal cancer cells,which was greater in KRAS-mutant cells.Furthermore,RGS induced mitotic arrest and oxidative stress-dependent apoptosis in KRAS-mutant DLD1 and HCT116 cells.Besides,RGS disrupted RAS signaling,and the inhibition of RAS/MEK/ERK was independent of cellular oxidative stress.Using patient-derived xenograft models,the response and tumor inhibition of RGS were significantly higher in the KRAS-mutant subgroup,while p-MEK,p-ERK,and p-AKT levels of RGS-treated tumors were significantly decreased.Finally,in a KRAS-mutant,chemotherapy-resistant patient-derived xenograft model,RGS showed a stronger therapeutic effect than the combination standard therapy involving fluoropyrimidine+oxaliplatin/irinotecan+bevacizumab.Conclusions:These data showed that targeting RAS signaling using RGS could be a therapeutic treatment for KRAS-mutant colorectal cancer patients.

PIK3CA mutation in Chinese patients with lung squamous cell carcinoma

Objective： To investigate PIK3CA mutation in Chinese patients with lung squamous cell carcinoma （LSCC） and explore their relationship with clinicopathological profiles. Methods： Tumor samples from 123 cases of LSCC were included in this study. PIK3CA mutations in exon 9 and 20 were screened by pyrosequencing and confirmed by clone sequencing or amplification refractory mutation system （ARMS）. Denaturing performance liquid chromatography （DHPLC） was employed for evaluation of EGFR mutation in exon 19, 21 and KRAS mutation. Results： PIK3CA mutations were found in 3 （2.4%） patients. The mutation type included E545K, E452Q and H1047R. Of these three patients, one coupled with EGFR mutation, and the other two coupled with PIK3CA amplification. All the three patients shared the same clinicopathologic characteristics： male, less than 60 years old, had smoke history, stage III and carried wild-type KRAS. Conclusions： The frequency of PIK3CA mutation is low in Chinese patients with LSCC. The mutational status of PIK3CA is not mutually exclusive to EGFR mutation.

Eye metastasis in lung adenocarcinoma mimicking anterior scleritis:A case report

BACKGROUND The eye is a rare site for lung cancer metastasis. Indeed, ocular metastasis is one of the greatest challenges to quality of life in a cancer patient. Here we present a patient with lung adenocarcinoma and ocular metastasis.CASE SUMMARY The patient was a 70-year-old man diagnosed with lung adenocarcinoma who developed eye metastasis mimicking anterior scleritis. Brain magnetic resonance imaging showed an abnormal signal in the right eye. Based on next generation sequencing of the surgical specimen, the patient was shown to have a KRAS point mutation(p.G12D).CONCLUSION Multidiscipline expertise collaboration is needed to make the early diagnosis and determine the prompt treatment in patients. We hope to increase the awareness of the possibility of lung cancer metastasizing to the eye.

Clinicopathological Characteristics and Prognosis of Patients with Adenosquamous Lung Carcinoma

This study was aimed to characterize clinicopathological features and prognosis of patients with adenosquamous lung carcinoma（ASC）. Among the 2531 patients with lung cancer who underwent surgery between January 2000 and June 2012 in our hospital, 59 were histologically diagnosed as having ASC. The clinicopathological features and follow-up data of ASC patients were collected and analyzed statistically. Superior lobectomy was accomplished in 40 patients, middle and inferior lobectomy in 3, lobectomy plus partial resection of contralateral lung in 5, partial lung resection in 4, and pneumonectomy in 7. Moreover, 22 cases were found to be adenocarcinoma-predominant, and 18 to be squamous cell carcinoma-predominant. The median survival time was 13.6 months, and the 1-, 3-, and 5-year survival rates were 59.9%, 36.4% and 31.2%, respectively. Of the 52 cases with tissue specimens available, 11 had an EGFR mutation（21.2%） and 2 had a KRAS mutation（3.8%）. Multivariate analysis showed that histology subtype, pleural invasion, TNM stage, and postoperative treatment were all independent prognostic factors. The data from the current study demonstrated that SCC-predominant histology represents a better prognosis of ASC. Histology subtype, pleural invasion, TNM stage, and postoperative treatment are independent prognostic factors for ASC and adjuvant therapy may help control the disease.

Clinical and molecular heterogeneity associated with tumor sidedness in colorectal liver metastasis: a multicenter propensity cohort study

Background:Colorectal liver metastasis(CRLM)exhibits highly heterogeneity,with clinically and molecularly defined subgroups that differ in their prognosis.The aim of this study is to explore whether left-sided tumors is clinically and gnomically distinct from right-sided tumors in CRLM.Methods:This retrospective study included 1,307 patients who underwent primary tumor and metastases resection at three academic centers in China from January 1,2012,to December 31,2020.Propensity score matching with 1:1 ratio matching was performed.The prognostic impact of tumor sidedness was determined after stratifying by the KRAS mutational status.Moreover,whole-exome sequencing(WES)of 200 liver tumor tissues were performed to describe the heterogeneity across the analysis of somatic and germline profiles.Results:The median follow-up was 68 months.Matching yielded 481 pairs of patients.Compared to right-sided CRLM,left-sided patients experienced with better 5-year overall survival(OS)in surgery responsiveness,with a 14.6 lower risk of death[hazard ratio(HR),1.36,95%confidence interval(CI),1.10-1.69,P=0.004].Interaction between tumor sidedness and KRAS status was statistically significant:left-sidedness was associated with better prognosis among KRAS wild-type patients(HR 1.71;95%CI:1.20-2.45;P=0.003),but not among KRAS mutated-type patients.Integrated molecular analyses showed that right-sided tumors more frequently harbored TP53,APC,KRAS,and BRAF alterations,and identified a critical role of KRAS mutation in correlation with their survival differences.Higher pathogenic germline variants were identified in the right-sided tumors compared with left-sided tumors(29.3%vs.15.5%,P=0.03).Conclusions:We demonstrated that the prognostic impacts of tumor sidedness in CRLM is restricted patients with KRAS wild-type tumors.Tumor sidedness displays considerable clinical and molecular heterogeneity that may associate with their therapy benefits and prognosis.

Resistance to immune checkpoint inhibitors in KRAS-mutant non-small cell lung cancer

Non-small cell lung cancer(NSCLC)patients with Kirsten rat sarcoma viral oncogene homolog(KRAS)mutation are associated with significant clinical heterogeneity and a poor prognosis to standard NSCLC therapies such as surgical resection,radiotherapy,chemotherapies,and targeted medicines.However,the application of immune checkpoints inhibitors(ICIs)has dramatically altered the therapeutic pattern of NSCLC management.Clinical studies have indicated that some KRAS-mutant NSCLC patients could benefit from ICIs;however,the responses in some patients are still poor.This review intends to elucidate the mechanisms of resistance to immunotherapy in KRAS-driven NSCLC and highlight the TME functions altered by immunoinhibitors,immunostimulators,and cancer metabolism.These metabolic pathways could potentially be promising approaches to overcome immunotherapy resistance.

Gene editing particle system as a therapeutic approach for drug-resistant colorectal cancer

The epidermal growth factor receptor(EGFR)pathway plays an important role in the progression of colorectal cancer(CRC).Anti-EGFR drugs based on antibodies have been widely used for treating CRC through inducing the cell death pathway.However,the majority of CRC patients will inevitably develop drug-resistance during anti-EGFR drug treatment,which is mainly caused by a point mutation in the KRAS oncogene.We developed a nanoliposomal(NL)particle containing the Cas9 protein and a single-guide RNA(sgRNA)complex(Cas9-RNP),for genomic editing of the KRAS mutation.The NL particle is composed of bio-compatible lipid compounds that can effectively encapsulate Cas9-RNP.By modifying the NL particle to include the appropriate antibody,it can specifically recognize EGFR expressing CRC and effectively deliver the gene-editing complexes.The conditions of NL treatment were optimized using a KRAS mutated CRC in vivo mouse model.Mice with KRAS-mutated CRC showed drug resistance against cetuximab,a therapeutic antibody drug.After treating the mice with the KRAS gene-editing NL particles,the implanted tumors showed a dramatic decrease in size.Our results demonstrated that this genomic editing complex has great potential as a therapeutic carrier system for the treatment of drug-resistant cancer caused by a point mutation.