Treating KRAS-mutant NSCLC: latest evidence and clinical consequences

Antagonistic interaction between miR-143 and KRAS gene regulating male mouse germ cell apoptosis

Precisely regulated spermatocyte growth, differentiation, and apoptosis are crucial for sustainable male fertility. miR-143 has been demonstrated to regulate gene expression and cell apoptosis in various human cancers. However, the function of mmu-mir-143 (miR-143) in mammalian testes and its underlying mechanism remains unexplored. In this study, the expression of miR-143 was detected in C57BL/6 mice spermatocytes by in situ hybridization (ISH) and immunofluorescence (IF) co-staining and transfecting miR-143 inhibitor into GC-2 cells (mouse spermatogenic cells) shows that miR-143 inhibits cleaved Caspase 3 (CC3)-induced male germ cell death. The current study used IF co-staining of KI67 and γ-H2A.X in the testes of C57BL/6 mice at different developmental stages, revealing that active proliferation and apoptosis of spermatocytes occurred simultaneously in the testes at 14 day post-partum (dpp). Kras was predicted as a potential target of miR-143 in mice using of the online database TargetScan, verified by quantitative real-time PCR (qPCR), western blotting (WB), and Dual-luciferase reporter gene assay. Co-transfection of miR-143 inhibitor and Kras siRNA into GC-2 cells revealed an antagonistic correlation between miR-143 and Kras in regulating male germ cell death. Finally, miR-143 inhibitor and mimics were administered into the seminiferous tubule of 3-week-old C57BL/6 mice. The histomorphology, IF co-staining, and WB data indicated that the testes treated with the miR-143 inhibitor showed significantly aberrant phenotypes, including damaged seminiferous tubules, reduced spermatocyte quantity, and elevated levels of apoptosis. This study uncovered the mechanism by which miR-143 inhibits male germ cell apoptosis through the repression of Kras/KRAS levels and the inhibition of Caspase 3 activation, providing insight into the role of miRNA in spermatogenesis and the maintenance of male fertility.

Analysis of the interlink between glucose-6-phosphate dehydrogenase (G6PD) and lung cancer through multi-omics databases

Glucose-6-Phosphate Dehydrogenase (G6PD) is a crucial enzyme that executes the pentose phosphate pathway. Due to its critical nodal position in the metabolic network, it is associated with different forms of cancer tumorigeneses and progression. Nonetheless, its functional role and molecular mechanism in lung cancer remain unknown. The present study provides intricate information associated with G6PD and Lung Cancer. Varieties of public datasets were retrieved by us, including UALCAN, TCGA, cBioPortal, and the UCSC Xena browser. The data obtained were used to assess the expression of G6PD, its clinical features, epigenetic regulation, relationship with tumour infiltration, tumour mutation burden, microsatellite instability, tumour microenvironment, immune checkpoint genes, genomic alteration, and patient's overall survival rate. The present study revealed that the G6PD expression was correlated with the clinical features of lung cancer including disease stage, race, sex, age, smoking habits, and lymph node metastasis. Moreover, the expression profile of G6PD also imparts epigenetic changes by modulating the DNA promoter methylation activity. Methylation of promoters changes the expression of various transcription factors, genes leading to an influence on the immune system. These events linked with G6PD-related mutational gene alterations (FAM3A, LAG3, p53, KRAS). The entire circumstance influences the patient's overall survival rate and poor prognosis. Functional investigation using STRING, GO, and KEGG found that G6PD primarily engages in hallmark functions (metabolism, immunological responses, proliferation, apoptosis, p53, HIF-1, FOXO, PI3K-AKT signaling). This work provides a wide knowledge of G6PD's function in lung cancer, as well as a theoretical foundation for possible prognostic therapeutic markers.

Targeting KRASG12C in Non-Small-Cell Lung Cancer: Current Standards and Developments

Among the most common molecular alterations detected in non-small-cell lung cancer (NSCLC) are mutations in Kristen Rat Sarcoma viral oncogene homolog (KRAS). KRAS mutant NSCLC is a heterogenous group of diseases, different from other oncogene-driven tumors in terms of biology and response to therapies. Despite efforts to develop drugs aimed at inhibiting KRAS or its signaling pathways, KRAS had remained undruggable for decades. The discovery of a small pocket in the binding switch II region of KRASG12C has revolutionized the treatment of KRASG12C-mutated NSCLC patients. Sotorasib and adagrasib, direct KRASG12C inhibitors, have been approved by the US Food and Drug Administration (FDA) and other regulatory agencies for patients with previously treated KRASG12C-mutated NSCLC, and these advances have become practice changing. However, first-line treatment in KRASG12C-mutated NSCLC does not differ from NSCLC without actionable driver genomic alterations. Treatment with KRASG12C inhibitors is not curative and patients develop progressive disease, so understanding associated mechanisms of drug resistance is key. New KRASG12C inhibitors and several combination therapy strategies, including with immune checkpoint inhibitors, are being studied in clinical trials. The aim of this review is to explore the clinical impact of KRAS, and outline different treatment approaches, focusing on the novel treatment of KRASG12C-mutated NSCLC.

Musashi-2 (MSI2) regulation of DNA damage response in lung cancer

Lung cancer is one of the most common types of cancer worldwide. Non-small cell lung cancer (NSCLC), typically caused by KRAS and TP53 driver mutations, represents the majority of all new lung cancer diagnoses. Overexpression of the RNA-binding protein (RBP) Musashi-2 (MSI2) has been associated with NSCLC progression. To investigate the role of MSI2 in NSCLC development, we compared the tumorigenesis in mice with lung-specific Kras-activating mutation and Trp53 deletion, with and without Msi2 deletion (KPM2 versus KP mice). KPM2 mice showed decreased lung tumorigenesis in comparison with KP mice. In addition, KPM2 lung tumors showed evidence of decreased proliferation, but increased DNA damage, marked by increased levels of phH2AX (S139) and phCHK1 (S345), but decreased total and activated ATM. Using cell lines from KP and KPM2 tumors, and human NSCLC cell lines, we found that MSI2 directly binds ATM mRNA and regulates its translation. MSI2 depletion impaired DNA damage response (DDR) signaling and sensitized human and murine NSCLC cells to treatment with PARP inhibitors in vitro and in vivo. Taken together, we conclude that MSI2 supports NSCLC tumorigenesis, in part, by supporting repair of DNA damage by controlling expression of DDR proteins. These results suggest that targeting MSI2 may be a promising strategy for lung cancers treated with DNA-damaging agents.

Detection of Single Nucleotide Polymorphisms of Circulating Tumor DNA by Strand Displacement Amplification Coupled with Liquid Chromatography

The detection of multiple single nucleotide polymorphisms (SNPs) of circulating tumor DNA (ctDNA) is still a great challenge. In this study, we designed enzyme-assisted nucleic acid strand displacement amplification combined with high-performance liquid chromatography (HPLC) for the simultaneous detection of three ctDNA SNPs. First, the trace ctDNA could be hybridized to the specially designed template strand, which initiated the strand displacement nucleic acid amplification process under the synergistic action of DNA polymerase and restriction endonuclease. Then, the targets would be replaced with G-quadruplex fluorescent probes with different tail lengths. Finally, the HPLC-fluorescence assay enabled the separation and quantification of multiple signals. Notably, this method can simultaneously detect both the wild type (WT) and mutant type (MT) of multiple ctDNA SNPs. Within a linear range of 0.1 fM-0.1 nM, the detection limits of BRAF V600E-WT, EGFR T790M-WT, and KRAS 134A-WT and BRAF V600E-MT, EGFR T790M-MT, and KRAS 134A-MT were 29, 31, and 11 aM and 22, 29, and 33 aM, respectively. By using this method, the mutation rates of multiple ctDNA SNPs in blood samples from patients with lung or breast cancer can be obtained in a simple way, providing a convenient and highly sensitive analytical assay for the early screening and monitoring of lung cancer.

Canadian Consensus Recommendations on the Management of KRAS G12C-Mutated NSCLC

Activating mutations in Kirsten rat sarcoma viral oncogene homologue (KRAS), in particular, a point mutation leading to a glycine-to-cysteine substitution at codon 12 (G12C), are among the most frequent genomic alterations in non-small cell lung cancer (NSCLC). Several agents targeting KRAS G12C have recently entered clinical development. Sotorasib, a first-in-class specific small molecule that irreversibly inhibits KRAS G12C, has since obtained Health Canada approval. The emergence of novel KRAS-targeted therapies warrants the development of evidence-based consensus recommendations to help clinicians better understand and contextualize the available data. A Canadian expert panel was convened to define the key clinical questions, review recent evidence, and discuss and agree on recommendations for the treatment of advanced KRAS G12C-mutated NSCLC. The panel agreed that testing for KRAS G12C should be performed as part of a comprehensive panel that includes current standard-of-care biomarkers. Sotorasib, the only approved KRAS G12C inhibitor in Canada, is recommended for patients with advanced KRAS G12C-mutated NSCLC who progressed on guideline-recommended first-line standard of care for advanced NSCLC without driver alterations (immune-checkpoint inhibitor(s) [ICIs] +/- chemotherapy). Sotorasib could also be offered as second-line therapy to patients who progressed on ICI monotherapy that are not candidates for a platinum doublet and those that received first-line chemotherapy with a contraindication to ICIs. Preliminary data indicate the activity of KRAS G12C inhibitors in brain metastases; however, the evidence is insufficient to make specific recommendations. Regular liver function monitoring is recommended when patients are prescribed KRAS G12C inhibitors due to risk of hepatotoxicity.

Musashi-2 (MSI2) regulation of DNA damage response in lung cancer

Lung cancer is one of the most common types of cancers worldwide. Non-small cell lung cancer (NSCLC), typically caused by KRAS and TP53 driver mutations, represents the majority of all new lung cancer diagnoses. Overexpression of the RNA-binding protein (RBP) Musashi-2 (MSI2) has been associated with NSCLC progression. To investigate the role of MSI2 in NSCLC development, we compared the tumorigenesis in mice with lung-specific Kras -activating mutation and Trp53 deletion, with and without Msi2 deletion (KP versus KPM2 mice). KPM2 mice showed decreased lung tumorigenesis in comparison with KP mice what supports published data. In addition, using cell lines from KP and KPM2 tumors, and human NSCLC cell lines, we found that MSI2 directly binds ATM/Atm mRNA and regulates its translation. MSI2 depletion impaired DNA damage response (DDR) signaling and sensitized human and murine NSCLC cells to treatment with PARP inhibitors in vitro and in vivo . Taken together, we conclude that MSI2 supports lung tumorigenesis, in part, by direct positive regulation of ATM protein expression and DDR. This adds the knowledge of MSI2 function in lung cancer development. Targeting MSI2 may be a promising strategy to treat lung cancer.

Significance

This study shows the novel role of Musashi-2 as regulator of ATM expression and DDR in lung cancer.

KRASG12C mutation-induced TOPK overexpression contributes to tumour progression in non-small cell lung cancer

KRAS mutation is the most frequent type of genetic mutation in non-small cell lung cancer (NSCLC), especially in lung adenocarcinoma. However, KRAS mutation can affect many biological processes and the mechanisms underlying KRAS mutation-mediate carcinogenesis in NSCLC have not been fully understood. In this research, we found that KRASG12C mutation was associated with the upregulation of T-LAK cell-originated protein kinase (TOPK), which is a well-known serine/threonine MAPK-like protein kinase implicated in tumorigenesis. The overexpression of TOPK significantly promoted the malignant phenotype of A549 cells, and TOPK silencing impaired the malignant phenotype with KRASG12C mutation. Moreover, we demonstrated that TOPK level was regulated by MAPK/ERK signalling and the transcription factor Elk1. TOPK was also found to promote the activation of NF-κB signalling in A549 cells with KRASG12C mutation via facilitating the phosphorylation of TAK1. In the in vivo tumorigenesis model, the administration of TOPK inhibitor OTS514 enhanced the anticancer effect of 5-FU, and the combinatory use of OTS514 and KRASG12C inhibitor AMG510 showed synergistic anti-tumour effect. These results suggest that KRAS-TOPK axis contributes to the progression of NSCLC and targeting this axis could synergize with anticancer effect of the existing chemotherapeutics.

Clinical Relevance of Targeted Therapy and Immune-Checkpoint Inhibition in Lung Cancer

Lung cancer (LC) represents the second most diagnosed tumor and the malignancy with the highest mortality rate. In recent years, tremendous progress has been made in the treatment of this tumor thanks to the discovery, testing, and clinical approval of novel therapeutic approaches. Firstly, targeted therapies aimed at inhibiting specific mutated tyrosine kinases or downstream factors were approved in clinical practice. Secondly, immunotherapy inducing the reactivation of the immune system to efficiently eliminate LC cells has been approved. This review describes in depth both current and ongoing clinical studies, which allowed the approval of targeted therapies and immune-checkpoint inhibitors as standard of care for LC. Moreover, the present advantages and pitfalls of new therapeutic approaches will be discussed. Finally, the acquired importance of human microbiota as a novel source of LC biomarkers, as well as therapeutic targets to improve the efficacy of available therapies, was analyzed. Therapy against LC is increasingly becoming holistic, taking into consideration not only the genetic landscape of the tumor, but also the immune background and other individual variables, such as patient-specific gut microbial composition. On these bases, in the future, the research milestones reached will allow clinicians to treat LC patients with tailored approaches.

Low muscle mass in lung cancer is associated with an inflammatory and immunosuppressive tumor microenvironment

BACKGROUND

Computed tomographies (CT) are useful for identifying muscle loss in non-small lung cancer (NSCLC) cachectic patients. However, we lack consensus on the best cutoff point for pectoralis muscle loss. We aimed to characterize NSCLC patients based on muscularity, clinical data, and the transcriptional profile from the tumor microenvironment to build a cachexia classification model.

METHODS

We used machine learning to generate a muscle loss prediction model, and the tumor's cellular and transcriptional profile was characterized in patients with low muscularity. First, we measured the pectoralis muscle area (PMA) of 211 treatment-naive NSCLC patients using CT available in The Cancer Imaging Archive. The cutoffs were established using machine learning algorithms (CART and Cutoff Finder) on PMA, clinical, and survival data. We evaluated the prediction model in a validation set (36 NSCLC). Tumor RNA-Seq (GSE103584) was used to profile the transcriptome and cellular composition based on digital cytometry.

RESULTS

CART demonstrated that a lower PMA was associated with a high risk of death (HR = 1.99). Cutoff Finder selected PMA cutoffs separating low-muscularity (LM) patients based on the risk of death (P-value = 0.003; discovery set). The cutoff presented 84% of success in classifying low muscle mass. The high risk of LM patients was also found in the validation set. Tumor RNA-Seq revealed 90 upregulated secretory genes in LM that potentially interact with muscle cell receptors. The LM upregulated genes enriched inflammatory biological processes. Digital cytometry revealed that LM patients presented high proportions of cytotoxic and exhausted CD8+ T cells.

CONCLUSIONS

Our prediction model identified cutoffs that distinguished patients with lower PMA and survival with an inflammatory and immunosuppressive TME enriched with inflammatory factors and CD8+ T cells.

KRAS-Mutant Non-Small-Cell Lung Cancer: From Past Efforts to Future Challenges

KRAS is the most frequently mutated oncogene identified in human cancers. Despite the numerous efforts to develop effective specific inhibitors against KRAS, this molecule has remained "undruggable" for decades. The development of direct KRAS inhibitors, such as sotorasib, the first FDA-approved drug targeting KRAS G12C, or adagrasib, was made possible with the discovery of a small pocket in the binding switch II region of KRAS G12C. However, a new challenge is represented by the necessity to overcome resistance mechanisms to KRAS inhibitors. Another area to be explored is the potential role of co-mutations in the selection of the treatment strategy, particularly in the setting of immune checkpoint inhibitors. The aim of this review was to analyze the state-of-the-art of KRAS mutations in non-small-cell lung cancer by describing the biological structure of KRAS and exploring the clinical relevance of KRAS as a prognostic and predictive biomarker. We reviewed the different treatment approaches, focusing on the novel therapeutic strategies for the treatment of KRAS-mutant lung cancers.

Direct Targeting KRAS Mutation in Non-Small Cell Lung Cancer: Focus on Resistance

Simple Summary

KRAS is the most frequently mutated oncogene in non-small cell lung cancers (NSCLC), with a frequency around 30%, and among them KRAS G12C mutation occurs in 11% of cases. KRAS mutations were for a long time considered to be non-targetable alterations or “undruggable”. Direct inhibition is actually developped with switch-II mutant selective covalent KRAS G12C inhibitors with small molecules such as sotorasib or adagrasib preventing conversion of the mutant protein to GTP-bound active state. Little is known about primary or acquired resistance. Acquired resistance does occur and could be related to genetic alterations in the nucleotide exchange function or adaptive mechanisms either in down-stream pathways or in newly expressed KRAS G12C mutation. Mechanisms of resistance could be classified as “on-target” mechanisms, involving KRAS G12C alterations, or “off-target” mechanisms, involving other gene alterations and/or phenotypic changes.

Abstract

KRAS is the most frequently mutated oncogene in non-small cell lung cancers (NSCLC), with a frequency of around 30%, and encoding a GTPAse that cycles between active form (GTP-bound) to inactive form (GDP-bound). The KRAS mutations favor the active form with inhibition of GTPAse activity. KRAS mutations are often with poor response of EGFR targeted therapies. KRAS mutations are good predictive factor for immunotherapy. The lack of success with direct targeting of KRAS proteins, downstream inhibition of KRAS effector pathways, and other strategies contributed to a focus on developing mutation-specific KRAS inhibitors. KRAS p.G12C mutation is one of the most frequent KRAS mutation in NSCLC, especially in current and former smokers (over 40%), which occurs among approximately 12–14% of NSCLC tumors. The mutated cysteine resides next to a pocket (P2) of the switch II region, and P2 is present only in the inactive GDP-bound KRAS. Small molecules such as sotorasib are now the first targeted drugs for KRAS G12C mutation, preventing conversion of the mutant protein to GTP-bound active state. Little is known about primary or acquired resistance. Acquired resistance does occur and may be due to genetic alterations in the nucleotide exchange function or adaptative mechanisms in either downstream pathways or in newly expressed KRAS G12C mutation.

Targeting KRAS in Non-Small Cell Lung Cancer

Kirsten Rat Sarcoma viral oncogene homolog (KRAS) is the most frequently altered oncogene in Non-Small Cell Lung Cancer (NSCLC). KRAS mutant tumors constitute a heterogeneous group of diseases, different from other oncogene-derived tumors in terms of biology and response to treatment, which hinders the development of effective drugs against KRAS. Therefore, for decades, despite enormous efforts invested in the development of drugs aimed at inhibiting KRAS or its signaling pathways, KRAS was considered to be undruggable. Recently, the discovery of a new pocket under the effector binding switch II region of KRAS G12C has allowed the development of direct KRAS inhibitors such as sotorasib, the first FDA-approved drug targeting KRAS G12C, or adagrasib, initiating a new exciting era. However, treatment with targeted KRAS G12C inhibitors also leads to resistance, and understanding the possible mechanisms of resistance and which drugs could be useful to overcome it is key. Among others, KRAS G12C (ON) tricomplex inhibitors and different combination therapy strategies are being analyzed in clinical trials. Another area of interest is the potential role of co-mutations in treatment selection, particularly immunotherapy. The best first-line strategy remains to be determined and, due to the heterogeneity of KRAS, is likely to be based on combination therapies.

Kirsten rat sarcoma viral oncogene homolog G12C mutant advanced non-small-cell lung cancer treated with MEK1/2 inhibitor trametinib: a case report

No targeted therapies are approved for non-small-cell lung cancer (NSCLC) with Kirsten rat sarcoma viral oncogene homolog (KRAS) mutation to date. Trametinib, a selective allosteric inhibitor of the MEK1/2, demonstrated debatable clinical activity in KRAS-mutant NSCLC. In this case, we present a recurrent advanced NSCLC with KRAS G12C mutation successfully treated with single-agent trametinib therapy. An 87-year-old man who underwent radiotherapy for the right lung adenocarcinoma was admitted to clinical oncology center for recurrent lesions in bilateral lungs. He was unwilling to perform second-line chemotherapy, but underwent molecular profiling and revealed the KRAS G12C mutation. The single-agent target therapy of trametinib showed clinical benefit without obvious toxicity. Furthermore, this report reviewed the previous date of the preclinical and clinical and summarized that KRAS G12C mutation may be more sensitive to the inhibition of mitogen-activated protein kinase kinase. This case advocates for routine screening of KRAS point mutations in the utility of precision medicine and suggests that treatment with trametinib in advanced NSCLC cases with KRAS G12C mutation is well tolerated and effective, especially for those very elderly or unsuitable for more aggressive chemotherapy.

Targeting KRAS in NSCLC: Old Failures and New Options for "Non-G12c" Patients

Kirsten Rat Sarcoma Viral Oncogene Homolog (KRAS) gene mutations are among the most common driver alterations in non-small cell lung cancer (NSCLC). Despite their high frequency, valid treatment options are still lacking, mainly due to an intrinsic complexity of both the protein structure and the downstream pathway. The increasing knowledge about different mutation subtypes and co-mutations has paved the way to several promising therapeutic strategies. Despite the best results so far having been obtained in patients harbouring KRAS exon 2 p.G12C mutation, even the treatment landscape of non-p.G12C KRAS mutation positive patients is predicted to change soon. This review provides a comprehensive and critical overview of ongoing studies into NSCLC patients with KRAS mutations other than p.G12C and discusses future scenarios that will hopefully change the story of this disease.

Recent advances in lung cancer genomics: Application in targeted therapy

Genomic characterization of lung cancer has not only improved our understanding of disease biology and carcinogenesis but also revealed several therapeutic opportunities. Targeting tumor dependencies on specific genomic alterations (oncogene addiction) has accelerated the therapeutic developments and significantly improved the outcomes even in advanced stage of disease. Identification of genomic alterations predicting response to specific targeted treatment is the key to success for this "personalized treatment" approach. Availability of multiple choices of therapeutic options for specific genomic alterations highlight the importance of optimum sequencing of drugs. Multiplex gene testing has become mandatory in view of constantly increasing number of therapeutic targets and effective treatment options. Influence of genomic characteristics on response to immunotherapy further makes comprehensive genomic profiling necessary before therapeutic decision making. A comprehensive elucidation of resistance mechanisms and directed treatments have made the continuum of care possible and transformed this deadly disease into a chronic condition. Liquid biopsy-based approach has made the dynamic monitoring of disease possible and enabled treatment optimizations accordingly. Current lung cancer management is the perfect example of "precision-medicine" in clinical oncology.

The Absence of Mutations in the Exon 2 KRAS Gene in Several Ethnic Groups in North Sumatra May Not the Main Factor for Lung Cancer

Background:

Rat Sarcoma (RAS) protein encoded Guanosine Triphosphate (GTP-ase) activity, known as a switch of cell proliferation. The mutation of this protein alters the early stage of carcinogenesis and along with the interaction with other oncogene drivers and environmental factors affect the clinical characteristics and prognosis in cancer patients, particularly lung cancer.

Objective:

This study aims to determine the Kristen Rat Sarcoma (KRAS) mutation in lung cancer patients in North Sumatera and evaluate factors that might contribute in the development of lung cancer in the absence of KRAS mutation.

Methods:

This was a retrospective cohort study enrolled 44 subjects age > 18 year with the diagnosis of lung cancer. Histopathology preparation was obtained from surgery, bronchoscopy, and percutaneus needle biopsy then formed as paraffin-block. KRAS mutation was analyzed using Polymerase Chain Reaction (PCR) method with specific primer of exon 2 for evaluating the expression of RAS protein then continued with Sanger Sequencing Method at 12th and 13th codon.

Results:

The majority of subjects were male, age > 40 years old, bataknese, heavy smoker, with Adenocarcinoma. Almost all the subjects showed the expression of exon 2 of RAS protein in PCR examinations. However, Sequencing analysis using Bioedit Software, BLASTs and Finch T showed GGT GGC as protein base 219-224 which represented 12th and 13th Codon 12 and 13. The results interpreted there was no mutations of exon 2 of KRAS in North Sumatera Population.

Conclusion:

The absence of KRAS mutation in exon 2 in several ethnics in North Sumatera populations was not the main factors of lung cancer.

AGO2 promotes tumor progression in KRAS-driven mouse models of non-small cell lung cancer

Lung cancer is the deadliest malignancy in the United States. Non-small cell lung cancer (NSCLC) accounts for 85% of cases and is frequently driven by activating mutations in the gene encoding the KRAS GTPase (e.g., KRASG12D). Our previous work demonstrated that Argonaute 2 (AGO2)-a component of the RNA-induced silencing complex (RISC)-physically interacts with RAS and promotes its downstream signaling. We therefore hypothesized that AGO2 could promote KRASG12D-dependent NSCLC in vivo. To test the hypothesis, we evaluated the impact of Ago2 knockout in the KPC (LSL-KrasG12D/+;p53f/f;Cre) mouse model of NSCLC. In KPC mice, intratracheal delivery of adenoviral Cre drives lung-specific expression of a stop-floxed KRASG12D allele and biallelic ablation of p53 Simultaneous biallelic ablation of floxed Ago2 inhibited KPC lung nodule growth while reducing proliferative index and improving pathological grade. We next applied the KPHetC model, in which the Clara cell-specific CCSP-driven Cre activates KRASG12D and ablates a single p53 allele. In these mice, Ago2 ablation also reduced tumor size and grade. In both models, Ago2 knockout inhibited ERK phosphorylation (pERK) in tumor cells, indicating impaired KRAS signaling. RNA sequencing (RNA-seq) of KPC nodules and nodule-derived organoids demonstrated impaired canonical KRAS signaling with Ago2 ablation. Strikingly, accumulation of pERK in KPC organoids depended on physical interaction of AGO2 and KRAS. Taken together, our data demonstrate a pathogenic role for AGO2 in KRAS-dependent NSCLC. Given the prevalence of this malignancy and current difficulties in therapeutically targeting KRAS signaling, our work may have future translational relevance.

First-in-human study of the safety, pharmacokinetics, and pharmacodynamics of first-in-class fatty acid synthase inhibitor TVB-2640 alone and with a taxane in advanced tumors

BACKGROUND

We conducted a first-in-human dose-escalation study with the oral FASN inhibitor TVB-2640 to determine the maximum tolerated dose (MTD) and recommended phase 2 dose (RP2D), as monotherapy and with a taxane.

METHODS

This completed open-label outpatient study was conducted at 11 sites in the United States and United Kingdom. Patients with previously-treated advanced metastatic solid tumors and adequate performance status and organ function were eligible. TVB-2640 was administered orally daily until PD. Dose escalation initially followed an accelerated titration design that switched to a standard 3 + 3 design after Grade 2 toxicity occurred. Disease-specific cohorts were enrolled at the MTD. Statistical analyses were primarily descriptive. Safety analyses were performed on patients who received at least 1 dose of study drug. (Clinicaltrials.gov identifier NCT02223247).

FINDINGS

The study was conducted from 21 November 2013 to 07 February 2017. Overall, 136 patients received TVB-2640, 76 as monotherapy (weight-based doses of 60 mg/m² to 240 mg/m² and flat doses of 200 and 250 mg) and 60 in combination, (weight-based doses of 60 mg/m² to 100 mg/m² and flat dose of 200 mg) (55 paclitaxel, 5 docetaxel). DLTs with TVB-2640 were reversible skin and ocular effects. The MTD/RP2D was 100 mg/m². The most common TEAEs (n,%) with TVB-2640 monotherapy were alopecia (46; 61%), PPE syndrome (35; 46%), fatigue (28; 37%), decreased appetite (20; 26%), and dry skin (17; 22%), and with TVB-2640+paclitaxel were fatigue (29 ; 53%), alopecia (25; 46%), PPE syndrome (25; 46%), nausea (22; 40%), and peripheral neuropathy (20; 36%). One fatal case of drug-related pneumonitis occurred with TVB-2640+paclitaxel; no other treatment-related deaths occurred. Target engagement (FASN inhibition) and inhibition of lipogenesis were demonstrated with TVB-2640. The disease control rate (DCR) with TVB-2640 monotherapy was 42%; no patient treated with monotherapy had a complete or partial response (CR or PR). In combination with paclitaxel, the PR rate was 11% and the DCR was 70%. Responses were seen across multiple tumor types, including in patients with KRAS^MUT NSCLC, ovarian, and breast cancer.

INTERPRETATION

TVB-2640 demonstrated potent FASN inhibition and a predictable and manageable safety profile, primarily characterized by non-serious, reversible adverse events affecting skin and eyes. Further investigation of TVB-2640 in patients with solid tumors, particularly in KRAS^MUT lung, ovarian, and breast cancer, is warranted.

FUNDING

This trial was funded by 3-V Biosciences, Inc. (now known as Sagimet Biosciences Inc.).

Cooperation between oncogenic Ras and wild-type p53 stimulates STAT non-cell autonomously to promote tumor radioresistance

Oncogenic RAS mutations are associated with tumor resistance to radiation therapy. Cell-cell interactions in the tumor microenvironment (TME) profoundly influence therapy outcomes. However, the nature of these interactions and their role in Ras tumor radioresistance remain unclear. Here we use Drosophila oncogenic Ras tissues and human Ras cancer cell radiation models to address these questions. We discover that cellular response to genotoxic stress cooperates with oncogenic Ras to activate JAK/STAT non-cell autonomously in the TME. Specifically, p53 is heterogeneously activated in Ras tumor tissues in response to irradiation. This mosaicism allows high p53-expressing Ras clones to stimulate JAK/STAT cytokines, which activate JAK/STAT in the nearby low p53-expressing surviving Ras clones, leading to robust tumor re-establishment. Blocking any part of this cell-cell communication loop re-sensitizes Ras tumor cells to irradiation. These findings suggest that coupling STAT inhibitors to radiotherapy might improve clinical outcomes for Ras cancer patients.

Genotype Driven Therapy for Non-Small Cell Lung Cancer: Resistance, Pan Inhibitors and Immunotherapy

Eighty-five percent of patients with lung cancer present with Non-small Cell Lung Cancer (NSCLC). Targeted therapy approaches are promising treatments for lung cancer. However, despite the development of targeted therapies using Tyrosine Kinase Inhibitors (TKI) as well as monoclonal antibodies, the five-year relative survival rate for lung cancer patients is still only 18%, and patients inevitably become resistant to therapy. Mutations in Kirsten Ras Sarcoma viral homolog (KRAS) and epidermal growth factor receptor (EGFR) are the two most common genetic events in lung adenocarcinoma; they account for 25% and 20% of cases, respectively. Anaplastic Lymphoma Kinase (ALK) is a transmembrane receptor tyrosine kinase, and ALK rearrangements are responsible for 3-7% of NSCLC, predominantly of the adenocarcinoma subtype, and occur in a mutually exclusive manner with KRAS and EGFR mutations. Among drug-resistant NSCLC patients, nearly half exhibit the T790M mutation in exon 20 of EGFR. This review focuses on some basic aspects of molecules involved in NSCLC, the development of resistance to treatments in NSCLC, and advances in lung cancer therapy in the past ten years. Some recent developments such as PD-1-PD-L1 checkpoint-based immunotherapy for NSCLC are also covered.

Impact of Somatic Mutations in Non-Small-Cell Lung Cancer: A Retrospective Study of a Chinese Cohort

Background

Somatic mutations are important biomarkers for selecting an optimal targeted therapy and predicting outcomes for non-small-cell lung cancer (NSCLC) patients that are often detected from tissue samples. However, tissue samples are not always readily available from these patients. The exploration of using circulating tumor DNA (ctDNA) to identify somatic mutations offers an alternative source that should be explored.

Methods

In this retrospective study, we included 280 patients diagnosed with adenocarcinoma between 2017 and 2018 in a hospital in eastern China. Tissue or ctDNA was collected, and a wide spectrum of somatic mutations was analyzed by targeted next-generation sequencing platforms. Associations among the mutation status, biomarkers, screening methods, disease stages, and interaction with treatment with overall survival (OS) were investigated.

Results

We found that the EGFR L858R mutation was the most frequently identified mutation in adenocarcinoma in this population by both methods, followed by KRAS (p=3.7e-09), PIK3CA (p=5e-04), and HER2 mutations (p=6.3e-03). We observed that EGFR mutations were significantly mutually exclusive with KRAS, HER2, and MET. FGFR1 mutations were significantly more abundantly detected in the ctDNA group. We found an interaction effect between EGFR mutation and target therapies. The ability of the targeted therapy to improve OS in patients with a single EGFR mutation (HR=0.069, p=0.07) approached significance, but this was not the case for the patients with more than one EGFR mutation or without an EGFR mutation (HR=0.813, p=0.725). Furthermore, the effect of chemotherapy was more predominant in the EGFR group in comparison to the control group.

Conclusion

These findings provide useful information on the distribution of somatic mutations via different screening methods and how this related to the optimal treatment selection in Chinese patients with NSCLC.

Genomic characteristics and drug screening among organoids derived from non-small cell lung cancer patients

BACKGROUND

Patient-derived organoid (PDO) models are highly valuable and have potentially widespread clinical applications. However, limited information is available regarding organoid models of non-small cell lung cancer (NSCLC). This study aimed to characterize the consistency between primary tumors in NSCLC and PDOs and to explore the applications of PDOs as preclinical models to understand and predict treatment response during lung cancer.

METHODS

Fresh tumor samples were harvested for organoid culture. Primary tumor samples and PDOs were analyzed via whole-exome sequencing. Paired samples were subjected to immunohistochemical analysis. There were 26 antineoplastic drugs tested in the PDOs. Cell viability was assessed using the Cell Titer Glo assay 7-10 days after drug treatment. A heatmap of log-transformed values of the half-maximal inhibitory concentrations was generated on the basis of drug responses of PDOs through nonlinear regression (curve fit). A total of 12 patients (stages I-III) were enrolled, and 7 paired surgical tumors and PDOs were analyzed.

RESULTS

PDOs retained the histological and genetic characteristics of the primary tumors. The concordance between tumors and PDOs in mutations in the top 20 NSCLC-related genes was >80% in five patients. Sample purity was significantly and positively associated with variant allele frequency (Pearson r = 0.82, P = 0.0005) and chromosome stability. The in vitro response to drug screening with PDOs revealed high correlation with the mutation profiles in the primary tumors.

CONCLUSIONS

PDOs are highly credible models for detecting NSCLC and for prospective prediction of the treatment response for personalized precision medicine.

KEY POINTS

Lung cancer organoid models could save precious time of drug testing on patients, and accurately select anticancer drugs according to the drug sensitivity results, so as to provide a powerful supplement and verification for the gene sequencing.

KRAS inhibition in non-small cell lung cancer: Past failures, new findings and upcoming challenges

Despite the high prevalence of Kirsten rat sarcoma (KRAS) mutations in non-small cell lung cancer (NSCLC), for a long time it has been defined as an 'undruggable target', with precision medicine not considered as an adequate approach to treat this subgroup of patients. After several years of efforts, preliminary data from early clinical trials have recently demonstrated that direct pharmacological inhibition of KRAS p.G12C mutation is possible, emerging as an effective targeted treatment for about 10-12% of patients with advanced NSCLC, with potential relevant impact on their long-term survival and quality of life. This review reports the current status of KRAS mutations detection in the Italian real-word scenario, summarises the biological basis of KRAS inhibition in NSCLC and provides an updated overview of therapeutic strategies, discussing the potential reasons for past failures and analysing the upcoming challenges related to the advent of new targeted agents in clinical practice.

External Quality Assessment Schemes for Biomarker Testing in Oncology: Comparison of Performance between Formalin-Fixed, Paraffin-Embedded-Tissue and Cell-Free Tumor DNA in Plasma

Liquid biopsies have emerged as a useful addition to tissue biopsies in molecular pathology. Literature has shown lower laboratory performances when a new method of variant analysis is introduced. This study evaluated the differences in variant analysis between tissue and plasma samples after the introduction of liquid biopsy in molecular analysis. Data from a pilot external quality assessment scheme for the detection of molecular variants in plasma samples and from external quality assessment schemes for the detection of molecular variants in tissue samples were collected. Laboratory performance and error rates by sample were compared between matrices for variants present in both scheme types. Results showed lower overall performance [65.6% (n = 276) versus 89.2% (n = 1607)] and higher error rates [21.0% to 43.5% (n = 138) versus 8.7% to 16.7% (n = 234 to 689)] for the detection of variants in plasma compared to tissue, respectively. In the plasma samples, performance was decreased for variants with an allele frequency of 1% compared to 5% [56.5% (n = 138) versus 74.6% (n = 138)]. The implementation of liquid biopsy in the detection of circulating tumor DNA in plasma was associated with poor laboratory performance. It is important both to apply optimal detection methods and to extensively validate new methods for testing circulating tumor DNA before treatment decisions are made.

The Activity of Immune Checkpoint Inhibition in KRAS Mutated Non-small Cell Lung Cancer: A Single Centre Experience

BACKGROUND/AIM

KRAS mutation is the most frequent molecular alteration found in advanced non-small cell lung cancer (NSCLC). It is associated with a poor prognosis without available targeted therapy. Treatment options for NSCLC have been recently enriched by the development of immune checkpoint inhibitors (ICIs), and data about their efficacy in patients with KRAS-mutant NSCLC are discordant. This study assessed the routine efficacy of ICIs in advanced KRAS-mutant NSCLC.

PATIENTS AND METHODS

All stage IV NSCLC patients treated in our institution from January 2016 to December 2017 with immunotherapy were included in our analysis. We collected the status of KRAS and other mutations, as well as the type of ICI administered. We assessed four clinical outcomes: i) disease control rate (DCR), ii) partial response (PR), iii) progression-free survival (PFS) and iv) overall survival (OS).

RESULTS

A total of 45 patients were initially identified but 7 were excluded due to insufficient clinical data, so 38 were included in the end. In the KRAS wild-type cohort, the DCR was 59% with 49% PR, while the PFS was 8.4 months and OS 16.8 months. Among KRAS mutated patients, results were more favourable, the DCR was 81%, with 62% PR. PFS was 13.6 months and OS was 18.5 months. The median follow-up was 24 months (17 to 34 months) and 7 patients were still on treatment at the time of analysis.

CONCLUSION

Our data suggest that KRAS mutation is predictive of a superior response to immunotherapy. Furthermore, the lack of response of STK11 and KRAS co-mutated NSCLC patients to ICIs, is indeed negated by an additional TP53 mutation.

Actionable Mutation Profiles of Non-Small Cell Lung Cancer patients from Vietnamese population

Comprehensive profiling of actionable mutations in non-small cell lung cancer (NSCLC) is vital to guide targeted therapy, thereby improving the survival rate of patients. Despite the high incidence and mortality rate of NSCLC in Vietnam, the actionable mutation profiles of Vietnamese patients have not been thoroughly examined. Here, we employed massively parallel sequencing to identify alterations in major driver genes (EGFR, KRAS, NRAS, BRAF, ALK and ROS1) in 350 Vietnamese NSCLC patients. We showed that the Vietnamese NSCLC patients exhibited mutations most frequently in EGFR (35.4%) and KRAS (22.6%), followed by ALK (6.6%), ROS1 (3.1%), BRAF (2.3%) and NRAS (0.6%). Interestingly, the cohort of Vietnamese patients with advanced adenocarcinoma had higher prevalence of EGFR mutations than the Caucasian MSK-IMPACT cohort. Compared to the East Asian cohort, it had lower EGFR but higher KRAS mutation prevalence. We found that KRAS mutations were more commonly detected in male patients while EGFR mutations was more frequently found in female. Moreover, younger patients (<61 years) had higher genetic rearrangements in ALK or ROS1. In conclusions, our study revealed mutation profiles of 6 driver genes in the largest cohort of NSCLC patients in Vietnam to date, highlighting significant differences in mutation prevalence to other cohorts.

Nootkatone, an AMPK activator derived from grapefruit, inhibits KRAS downstream pathway and sensitizes non-small-cell lung cancer A549 cells to adriamycin

BACKGROUND

Non-small-cell lung cancer (NSCLC) accounts for approximately 85% of all lung cancer cases and it is intrinsically resistant to anticancer drugs. Nootkatone (NKT), which is the main fragrant component of grapefruit, has been identified as a bioactive compound with a wide range of beneficial applications. NKT can activate AMP-activated protein kinase (AMPK) in liver and muscle cells, however, little is known about the role of NKT in cancer, particularly its role in NSCLC with high rates of liver kinase B1 (LKB1) and KRAS mutations.

PURPOSE

The anti-cancer activities of NKT in NSCLC A549 cells and ADR-resistant A549/ADR cells were investigated and compared to those of metformin, an AMPK activator that is used clinically as an AMPK activator.

METHODS

Cell viability, proliferation and NKT sensitization were determined by the MTT assay. Mechanisms of NKT against anti-cancer activities including AMPK activation, cell cycle arrest, and synergistic cytotoxic effect were evaluated by Western blot analysis, and flow cytometry. In in vivo experiments, athymic BALB/c male nude mice were used for experiments. After the successful generation of tumor models through subcutaneous injection of A549/ADR cells, NKT and/or ADR were administered and mice were kept for weekly measurements for up to 7 weeks. The animals were then sacrificed, and the tumors were removed from all animals and weighed.

RESULTS

NKT activated AMPK via LKB1-independent and CAMKK2-dependent pathways, leading to inhibition of cell growth and induction of G1 cell arrest. The effect of NKT is comparable but superior to that of metformin, an AMPK activator in clinical use. Importantly, NKT inhibited the activation of oncogenic AKT and ERK proteins, while metformin inhibited AKT but failed to impact ERK, the major oncogenic protein of NSCLC cells with KRAS mutation. The synergistic activity of NKT and ADR was more effective than that of metformin and ADR. In vivo data confirmed synergistic effects of NKT and ADR without systemic side effects.

CONCLUSION

We demonstrate for the first time that NKT can sensitize ADR-resistant A549/ADR cells to ADR in vitro and in vivo. Metformin, on the other hand, failed to show any synergistic effect with ADR in A549/ADR cells.

KRAS-mutant non-small cell lung cancer: Converging small molecules and immune checkpoint inhibition

KRAS is the most frequent oncogene in non-small cell lung cancer (NSCLC), a molecular subset characterized by historical disappointments in targeted treatment approaches such as farnesyl transferase inhibition, downstream MEK inhibition, and synthetic lethality screens. Unlike other important mutational subtypes of NSCLC, preclinical work supports the hypothesis that KRAS mutations may be vulnerable to immunotherapy approaches, an efficacy associated in particular with TP53 co-mutation. In this review we detail reasons for previous failures in KRAS-mutant NSCLC, evidence to suggest that KRAS mutation is a genetic marker of benefit from immune checkpoint inhibition, and emerging direct inhibitors of K-Ras which will soon be combined with immunotherapy during clinical development. With signs of real progress in this subgroup of unmet need, we anticipate that KRAS mutant NSCLC will be the most important molecular subset of cancer to evaluate the combination of small molecules and immune checkpoint inhibitors (CPI).

Intratumor heterogeneity comparison among different subtypes of non-small-cell lung cancer through multi-region tissue and matched ctDNA sequencing

Understanding of intratumor heterogeneity (ITH) among different non-small cell lung cancer (NSCLC) subtypes is necessary. Whether circulating tumor DNA (ctDNA) profile could represent these ITH is still an open question. We performed 181 multi-region tumor tissues sequencing and matched ctDNA sequencing from 32 operative NSCLC to compare ITH among different NSCLC subtypes, including EGFR-mutant lung adenocarcinoma (LUAD), KRAS-mutant LUAD, EGFR&KRAS-wild-type LUAD, and lung squamous cell carcinoma (LUSC), and examine potential value of ctDNA for ITH analysis. ITH is evaluated by ITH index (ITHi). If the somatic genetic alteration is shared by all the tissue regions, it is defined as trunk mutation. Otherwise, it is called branch mutation. The ITHi will be higher, if the tumor has less trunk mutations. We found EGFR-mutant LUAD showed significantly higher ITHi than KRAS-mutant LUAD/wild-type LUAD (P = 0.03) and numerically higher ITH than LUSC. For trunk mutations, driver mutations were identified at a higher proportion than passenger mutations (60% vs. 40%, P = 0.0023) in overall, especially in EGFR-mutant LUAD (86% vs. 14%, P = 0.0004), while it was opposite in KRAS-mutant LUAD (40% vs. 60%, P = 0.18). For branch mutations, the proportions of driver mutations and passenger mutations were similar for each NSCLC subtype. ctDNA analysis showed unsatisfactory detections of tumor-derived trunk and branch mutations (43% vs. 23%, P = 4.53e-6) among all NSCLC subtypes. In summary, EGFR-mutant LUAD has the highest ITH than other NSCLC subtypes, offering further understanding of tumorigenesis mechanisms among different NSCLC subtypes. Besides, ctDNA maybe not an appropriate method to reflect ITH.

Modified SureSelectQXT Target Enrichment Protocol for Illumina Multiplexed Sequencing of FFPE Samples

Background

Personalised medicine is nowadays a major objective in oncology. Molecular characterization of tumours through NGS offers the possibility to find possible therapeutic targets in a time- and cost-effective way. However, the low quality and complexity of FFPE DNA samples bring a series of disadvantages for massive parallel sequencing techniques compared to high-quality DNA samples (from blood cells, cell cultures, etc.).

Results

We performed several experiments to understand the behaviour of FFPE DNA samples during the construction of SureSelect^QXT libraries. First, we designed a quality checkpoint for FFPE DNA samples based on the quantification of their amplification capability (qcPCR). We observed that FFPE DNA samples can be classified according to DIN value and qcPCR concentration into unusable, or low-quality (LQ) and good-quality (GQ) DNA. For GQ samples, we increased the amount of input DNA to 150 ng and the digestion time to 30 min, whereas for LQ samples, we used 50 ng of DNA as input but we decreased the digestion time to 1 min. In all cases, we increased the cycles of the pre-hyb PCR to 10 but decreased the cycles of the post-hyb PCR to 8. In addition, we confirmed that using half of the volume of reagents can be beneficial. Finally, in order to obtain better results, we designed a decision flow-chart to achieve a seeding concentration of 12–14 pM for MiSeq Reagent Kit v2.

Conclusions

Our experiments allowed us to unveil the behaviour of low-quality FFPE DNA samples during the construction of SureSelect^QXT libraries. Sequencing results showed that, using our modified SureSelect^QXT protocol, the final percentage of usable reads for low-quality samples was increased more than three times allowing to reach median depth/million reads values of 76.35. This value is equivalent to ~ 0.9 and ~ 0.7 of the values obtained for good-quality FFPE and high-quality DNA respectively.

Electronic supplementary material

The online version of this article (10.1186/s12575-018-0084-7) contains supplementary material, which is available to authorized users.

Preclinical, non-genetic models of lung adenocarcinoma: a comparative survey

Lung cancer is the leading cause of cancer-related mortality worldwide. Animal models are key in analyzing cancer biology and therapy evaluation. We here compared relevant non-genetic lung cancer models with regard to tumor induction period, incidence, morbidity and mortality rate and the immunological composition of primary tumors and the occurrence of tertiary lymphoid organs (TLO): (I) intraperitoneal Urethane injection (1g/kg), (II) Lewis lung carcinoma (LLC) cell line model (intravenous or subcutaneous), and (III) ex vivo three-dimensional (3D) primary cell culture model established from subcutaneously developed LLC-induced tumors. The incidence of Urethane induced lung tumors was 100% in both, C57BL/6 and BALB/c strains without morbidity or mortality at twenty weeks after injection. The mean size of tumor nodules after Urethane injection was significantly larger in BALB/c mice vs. C57BL/6 (p<0.01). Three times of Urethane injection produced significantly more tumor nodules in both mouse strains compared to one injection (BALB/c: p<0.01; C57BL/6: p<0.05). TLOs were only found in the Urethane-induced model. Although the cell line models also showed 100% induction rate, morbidity was high due to skin ulceration on the inoculation site and the development of pleural effusions in the subcutaneous model and the intravenous model, respectively. Tendencies, but no significant differences (p>0.05) could be found in the count of CD4⁺, CD8⁺, F4/80⁺ and NKp46⁺ cells in a tumor nodule among investigated models. All discussed models provided a high tumor incidence rate. TLOs were exclusively found in the Urethane-induced model. No significant difference could be found regarding immune cells across models.

Immunotherapy in the Asiatic population: any differences from Caucasian population?

As "Immunotherapy age" is coming, immune checkpoint inhibitors (CPI) therapies have shown favorable clinical benefits and low toxicity profiles in patients with advanced non-small cell lung cancer (NSCLC). While it is a pity that there is a little clear clinical trials evidence about immunotherapy among Asian population. Moreover, since there is an ethnic difference for targeted therapy, what about immunotherapy? Which factors may associate with ethnic differences from Caucasian population to Asiatic population? In this review, we supposed that the characteristics of the much higher proportion of EGFR mutation, hepatitis B virus infection and unexpected immune-related toxicity among Asian patients should be considered.