The Prognostic and Therapeutic Potential of DNA Damage Repair Pathway Alterations and Homologous Recombination Deficiency in Lung Cancer

Haematologic outcomes and associated clinical characteristics among patients receiving Olaparib therapy in the UAE: a retrospective chart review

BACKGROUND

Poly ADP ribose polymerase (PARP) inhibitors, such as Olaparib (Lynparza®), are pivotal in treating certain cancers, particularly those linked to BReast CAncer gene (BRCA) mutations. Despite its established efficacy, Olaparib use is associated with various adverse events (AEs), notably haematologic toxicities, such as anaemia. This retrospective chart review study aimed to examine haematologic outcomes and associated factors in patients treated with Olaparib at a tertiary hospital in the UAE.

METHODS

We reviewed the medical charts of patients prescribed Olaparib and focused on haematologic indices at a baseline of 1-month, 3-month and 6-month follow-up periods. Data were analysed to determine the AEs frequency, transfusions need and potential associated patients' clinical characteristics.

RESULTS

This study included all patients who received Olaparib (n = 66). Most patients were females (n = 61; 92.4%) and the vast majority were non-smokers (97%) and free of hepatic disease. Themean age of the patients was 57.03-year-old (SD) = 12.06 years), and body mass index (BMI) was 28.16 (SD = 6.40) kg/m2. A high rate of anaemia (70.8%) was detected among the patients during their Olaparib therapy. Approximately, one-third of the patients developed neutropenia and thrombocytopenia. Transfusion was needed in almost half of the patients. Glomerular filtration rate (GFR) and neutropenia were significantly correlated with moderate-severe anaemia (OR = 0.097, 95% CI: 0.011-0.88, p value = .038) and (OR = 9.04, 95% CI: 1.024-79.78, p value = .048), respectively.

CONCLUSIONS

Our findings highlight the side effects of Olaparib therapy in terms of haematology which could be avoided. Further studies are needed to better understand the therapeutic management of Olaparib and the mitigation of haematologic complications.

Deregulated methylation and expression of PCDHGB7 in patients with non-small cell lung cancer: a novel prognostic and immunological biomarker

Backgrounds

Protocadherin gamma subfamily B, 7 (PCDHGB7), a member of the protocadherin family, plays critical roles in neuronal connections and has been implicated in female reproductive system cancers. Its function in lung cancer has not been elucidated.

Methods

We comprehensively investigated PCDHGB7 expression, prognosis, biological function, methylation patterns, and it's relationship with immune infiltration and immunotherapy response through public datasets (HPA, TCGA, GEO, OncoDB and MEXPRESS). Two lung cancer immunotherapy cohorts from our clinical center were enrolled to detect the relationship between methylation and protein levels of PCDHGB7 in plasma and immunotherapy outcomes.

Results

PCDHGB7 expression was downregulated in lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) and associated with tumor prognosis. PCDHGB7 demonstrated a positive correlation with inhibitory immune cells and a negative correlation with tumor mutational burden (TMB) and homologous recombination deficiency (HRD). The methylation level of PCDHGB7 was upregulated in tumor tissue and negatively correlated with PCDHGB7 mRNA level. In immunotherapy cohort studies, patients with higher PCDHGB7 tissue expression showed worse prognosis. Patients with PCDHGB7 hypermethylation in baseline plasma had shorter progression-free survival (PFS) and overall survival (OS), while those with early reduction of PCDHGB7 methylation had the best prognosis. Plasma PCDHGB7 protein levels could predict responses to immune checkpoint inhibitors and function as a prognostic marker for PFS.

Conclusion

PCDHGB7 expression and methylation are prognostic and immunological biomarkers in non-small cell lung cancer. Plasma PCDHGB7 methylation and protein levels can be used as novel biomarkers for predicting the efficacy of immunotherapy in lung cancer.

Association of Germline Pathogenic Variants in MUTYH and Other DNA Damage Response Genes With Lung Cancer Risk Among Non-Hispanic Whites and African Americans

PURPOSE

Although lung cancer is one of the most common malignancies, the underlying genetics regarding susceptibility remain poorly understood. We characterized the spectrum of pathogenic/likely pathogenic (P/LP) germline variants within DNA damage response (DDR) genes among lung cancer cases and controls in non-Hispanic Whites (NHWs) and African Americans (AAs).

MATERIALS AND METHODS

Rare, germline variants in 67 DDR genes with evidence of pathogenicity were identified using the ClinVar database. These P/LP variants were genotyped in a sample of 3,040 lung cancer cases and controls from the Inflammation, Health, Ancestry, and Lung Epidemiology study (NHW: n = 1,915; AA: n = 1,125) and were tested for their association with lung cancer using multivariate logistic regression adjusting for age, sex, pack-years, and race.

RESULTS

We identified 49 unique rare P/LP variants in 21 genes among 156 carriers. Approximately 5.9% of lung cancer cases and 4.2% of controls carried at least one P/LP variant. P/LP variants in DDR genes were more common in lung cancer cases, particularly those diagnosed with adenocarcinoma (odds ratio [OR], 1.46 [95% CI, 1.00 to 2.14]). MUTYH variants were associated with lung cancer overall (OR, 1.82 [95% CI, 1.10 to 3.12]), with the strongest associations among never smokers (OR, 3.37 [95% CI, 1.08 to 10.26]), and in individuals who do not meet current USPSTF screening criteria (OR, 2.85 [95% CI, 1.20 to 7.53]).

CONCLUSION

Germline variants in DDR genes appear to be associated with lung cancer, particularly when examined by gene subtype and morphologic subtype. MUTYH, a gene historically associated with colorectal and other GI malignancies, emerged as a candidate gene that should be examined in individuals who do not have a significant smoking history.

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.

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.

New Approaches in Early-Stage NSCL Management: Potential Use of PARP Inhibitors and Immunotherapy Combination

Lung cancer is the second most common cancer in the world, being the first cause of cancer-related mortality. Surgery remains the only potentially curative treatment for Non-Small Cell Lung Cancer (NSCLC), but the recurrence risk remains high (30-55%) and Overall Survival (OS) is still lower than desirable (63% at 5 years), even with adjuvant treatment. Neoadjuvant treatment can be helpful and new therapies and pharmacologic associations are being studied. Immune Checkpoint Inhibitors (ICI) and PARP inhibitors (PARPi) are two pharmacological classes already in use to treat several cancers. Some pre-clinical studies have shown that its association can be synergic and this is being studied in different settings. Here, we review the PARPi and ICI strategies in cancer management and the information will be used to develop a clinical trial to evaluate the potential of PARPi association with ICI in early-stage neoadjuvant setting NSCLC.

PD-1/PD-L1 and DNA Damage Response in Cancer

The application of immunotherapy for cancer treatment is rapidly becoming more widespread. Immunotherapeutic agents are frequently combined with various types of treatments to obtain a more durable antitumor clinical response in patients who have developed resistance to monotherapy. Chemotherapeutic drugs that induce DNA damage and trigger DNA damage response (DDR) frequently induce an increase in the expression of the programmed death ligand-1 (PD-L1) that can be employed by cancer cells to avoid immune surveillance. PD-L1 exposed on cancer cells can in turn be targeted to re-establish the immune-reactive tumor microenvironment, which ultimately increases the tumor's susceptibility to combined therapies. Here we review the recent advances in how the DDR regulates PD-L1 expression and point out the effect of etoposide, irinotecan, and platinum compounds on the anti-tumor immune response.