PPAR-γ/NF-kB/AQP3 axis in M2 macrophage orchestrates lung adenocarcinoma progression by upregulating IL-6.

Aquaporin 3 (AQP3), which is mostly expressed in pulmonary epithelial cells, was linked to lung adenocarcinoma (LUAD). However, the underlying functions and mechanisms of AQP3 in the tumor microenvironment (TME) of LUAD have not been elucidated. Single-cell RNA sequencing (scRNA-seq) was used to study the composition, lineage, and functional states of TME-infiltrating immune cells and discover AQP3-expressing subpopulations in five LUAD patients. Then the identifications of its function on TME were examined in vitro and in vivo. AQP3 was associated with TNM stages and lymph node metastasis of LUAD patients. We classified inter- and intra-tumor diversity of LUAD into twelve subpopulations using scRNA-seq analyses. The analysis showed AQP3 was mainly enriched in subpopulations of M2 macrophages. Importantly, mechanistic investigations indicated that AQP3 promoted M2 macrophage polarization by the PPAR-γ/NF-κB axis, which affected tumor growth and migration via modulating IL-6 production. Mixed subcutaneous transplanted tumor mice and Aqp3 knockout mice models were further utilized, and revealed that AQP3 played a critical role in mediating M2 macrophage polarization, modulating glucose metabolism in tumors, and regulating both upstream and downstream pathways. Overall, our study demonstrated that AQP3 could regulate the proliferation, migration, and glycometabolism of tumor cells by modulating M2 macrophages polarization through the PPAR-γ/NF-κB axis and IL-6/IL-6R signaling pathway, providing new insight into the early detection and potential therapeutic target of LUAD.

Comprehensive analysis of prognostic value and immune infiltration of Regulator of Chromosome Condensation 2 in lung adenocarcinoma.

Background: Lung adenocarcinoma (LUAD) incidence and mortality take the leading place of most malignancies. Previous studies have revealed the regulator of chromosome condensation 1 (RCC1) family members played an essential role during tumorigenesis. However, its biological functions in LUAD still need further investigation. Methods: Several databases were applied to explore potential effects of RCC1 family members on LUAD, such as Oncomine, GEPIA, and cBioPortal. Real-time PCR and immunohistochemistry were used to verify the expression of RCC2 in stage I LUAD. H1975 and A549 were selected to explore the biological function of RCC2 in cellular malignant phenotype. Results: The expressions of RCC1 and RCC2 showed marked differences in malignant tissue compared to lung tissue. The higher the expression levels of RCC1 or RCC2 in LUAD patients, the shorter their overall survival (OS). In normal lung tissues, RCC1 expression was highly enriched in alveolar cells and endothelial cells. Compare with RCC1, RCC2 expression in normal lung tissue was significantly enriched in macrophages, B cells and granulocytes. Additionally, RCC2 expression level was correlated with multiple immune cell infiltration in LUAD. Moreover, the mutation or different sCNA status of RCC2 exerted influence on multiple immune cell infiltration distribution. We found that the upregulation of RCC1 and RCC2 were obviously related to TP53 mutation. GSEA analysis revealed that RCC2 was involved in the process of DNA replication, nucleotide excision repair and cell cycle, which might affect tumor progression through P53 signaling pathway. We further elucidated that downregulation of RCC2 could dramatically repress the migration and invasion of LUAD cells. Conclusions: The study demonstrated that RCC1 and RCC2 expression were markedly increased in early-stage of LUAD. Patients with high expression of RCC1 or RCC2 had a worse prognosis. Based on our analysis, RCC1 and RCC2 might exert influence on LUAD process through DNA replication, nucleotide excision repair and cell cycle, as well as cells migration and invasion. Different from RCC1, RCC2 also involved in immune infiltration. These analyses provided a novel insight into the identification of diagnostic biomarker.

FUT3 facilitates glucose metabolism of lung adenocarcinoma via activation of NF-κB pathway.

OBJECTIVE: Fucosyltransferases (FUTs) molecules have been identified to be involved in carcinogenesis of malignant tumors. Nevertheless, the biological function of fucosyltransferases-3 (FUT3) in lung adenocarcinoma (LUAD) malignant phenotype remains unclear. Herein, we investigated the association between FUT3 and LUAD pathological process. METHODS: Immunochemistry, RT-qPCR and western blot assays were conducted to evaluate the expression of FUT3 in LUAD and corresponding adjacent tissues. The prognostic value of FUT3 was assessed via Kaplan­Meier plotter database. The biological process and potential mechanism of FUT3 in LUAD were conducted via GSEA. Additionally, immunofluorescence and metabolite activity detection were performed to determine the potential role of FUT3 in LUAD glucose metabolism. The active biomarkers associated with NF-κB signaling pathway were detected via western blot. Subcutaneous tumor model was conducted to analyze the effect of FUT3 on tumorigenesis of LUAD. RESULTS: FUT3 was remarkably upregulated in LUAD tissues compared with adjacent tissues from individuals. FUT3 overexpression may predict poor prognosis of LUAD patients. Knockdown of FUT3 significantly inhibited tumor proliferation, migration and glucometabolic alteration in LUAD cells. Moreover, GSEA demonstrated that elevated FUT3 was positively related to NF-κB signaling pathway. Additionally, in vitro and in vivo assays also indicated that downregulation of FUT3 resulted in the suppression of oncogenesis and glucose metabolism via inactivation of NF-κB pathway. CONCLUSION: Our findings demonstrated that FUT3 was involved in glucometabolic process and tumorigenesis of LUAD via NF-κB signaling pathway. FUT3 may be an optimal target for diagnosis and treatment of LUAD patients.

Thyroid Dysfunction in Non-Small Cell Lung Cancer With Immune Checkpoint Inhibitors: A Meta-Analysis.

Immune checkpoint inhibitors (ICIs) have been established as the cornerstone for advanced non-small cell lung cancer, while thyroid adverse events (AEs) associated with ICIs have not been systematically documented. Therefore, we performed a meta-analysis to evaluate the effect of ICI applications on the thyroid of patients with non-small cell lung cancer. We performed a systematic search of PubMed, the Cochrane Library, Web of Science, and Embase for eligible randomized controlled trials up to December 2021. Clinical trials reporting thyroid AEs including hypothyroidism, hyperthyroidism, and thyroiditis were enrolled. The I2  statistic was also calculated to quantify the heterogeneity. Data were evaluated as risk ratio (RR) and corresponding 95%CIs. A total of 10 randomized clinical trials involving 6154 patients were included in this meta-analysis. ICI application was found to have a statistically significant higher risk of all grade hypothyroidism (RR, 7.03; P < 0.0001), hyperthyroidism (RR, 4.88; P < 0.0001), and thyroiditis (RR, 6.58; P = 0.0014) compared with the chemotherapy group. Moreover, we demonstrated that second-line therapy significantly increased the risk of all-grade hypothyroidism (RR, 7.03 [95%CI, 4.69-10.55]) and hyperthyroidism (RR, 4.88 [95%CI, 3.11-7.65]). Our meta-analysis manifested that regimens with ICIs may significantly increase all grades of hypothyroidism, hyperthyroidism, and thyroiditis. ICIs may induce the occurrence and exacerbation of endocrine AEs compared with chemotherapy.

Identification of Small Airway Epithelium-Related Hub Genes in Chronic Obstructive Pulmonary Disease.

Background: Pulmonary small airway epithelia are the primary site of cellular and histological alterations in chronic obstructive pulmonary disease (COPD), while the potential therapeutic hub genes of pulmonary epithelia are rarely identified to elucidate profound alterations in the progression of the disease. Methods: Microarray dataset of GSE11906 containing small airway epithelia from 34 healthy non-smokers and 33 COPD patients was applied to screen differentially expressed genes (DEGs). Weighted gene correlation network analysis (WGCNA) was further used to identify the hub genes related to clinical features. Moreover, single-cell RNA sequencing data from GSE173896 and GSE167295 dataset were applied to explore the expression and distribution of the hub genes. The expression levels of hub genes in epithelial cells stimulated by cigarette smoke extract (CSE) were detected by RT-qPCR. Results: Ninety-eight DEGs correlated with clinical features of COPD were identified via limma and WGCNA. Eight hub genes (including AKR1C3, ALDH3A1, AKR1C1, CYP1A1, GPX2, CBR3, AKR1B1 and GSR) that might exert an antioxidant role in COPD process were identified. Single-cell transcriptomic analysis indicated that the expressions of AKRAC3, ALDH3A1, GPX2, CBR3 and AKR1B1 were significantly increased in the COPD group when compared with the normal group. Moreover, we found that the expression of ALDH3A1 was the most abundantly expressed in ciliated cells. RT-qPCR results indicated that the majority of candidate novel genes were significantly elevated when the epithelial cells were exposed to CSE. Conclusion: Through integrating limma, WGCNA, and protein-protein interaction (PPI) analysis, a total of eight candidate hub genes of pulmonary airway epithelia were identified in COPD. Moreover, single-cell transcriptomic analysis indicated that ALDH3A1 was enriched in ciliated cells, which may provide a new insight into the pathogenesis and treatment of COPD.

Integrated profiling of endoplasmic reticulum stress-related DERL3 in the prognostic and immune features of lung adenocarcinoma.

Background: DERL3 has been implicated as an essential element in the degradation of misfolded lumenal glycoproteins induced by endoplasmic reticulum (ER) stress. However, the correlation of DERL3 expression with the malignant phenotype of lung adenocarcinoma (LUAD) cells is unclear and remains to be elucidated. Herein, we investigated the interaction between the DERL3 and LUAD pathological process. Methods: The Cancer Genome Atlas (TCGA) database was utilized to determine the genetic alteration of DERL3 in stage I LUAD. Clinical LUAD samples including carcinoma and adjacent tissues were obtained and were further extracted to detect DERL3 mRNA expression via RT-qPCR. Immunohistochemistry was performed to evaluate the protein expression of DERL3 in LUAD tissues. The GEPIA and TIMER website were used to evaluate the correlation between DERL3 and immune cell infiltration. We further used the t-SNE map to visualize the distribution of DERL3 in various clusters at the single-cell level via TISCH database. The potential mechanisms of the biological process mediated by DERL3 in LUAD were conducted via KEGG and GSEA. Results: It was indicated that DERL3 was predominantly elevated in carcinoma compared with adjacent tissues in multiple kinds of tumors from the TCGA database, especially in LUAD. Immunohistochemistry validated that DERL3 was also upregulated in LUAD tissues compared with adjacent tissues from individuals. DERL3 was preliminarily found to be associated with immune infiltration via the TIMER database. Further, the t-SNE map revealed that DERL3 was predominantly enriched in plasma cells of the B cell population. It was demonstrated that DERL3 high-expressed patients presented significantly worse response to chemotherapy and immunotherapy. GSEA and KEGG results indicated that DERL3 was positively correlated with B cell activation and unfolded protein response (UPR). Conclusion: Our findings indicated that DERL3 might play an essential role in the endoplasmic reticulum-associated degradation (ERAD) process in LUAD. Moreover, DERL3 may act as a promising immune biomarker, which could predict the efficacy of immunotherapy in LUAD.

KCNK3 inhibits proliferation and glucose metabolism of lung adenocarcinoma via activation of AMPK-TXNIP pathway.

Non-small cell lung cancer (NSCLC) is a primary histological subtype of lung cancer with increased morbidity and mortality. K+ channels have been revealed to be involved in carcinogenesis in various malignant tumors. However, TWIK-related acid-sensitive potassium channel 1 (TASK-1, also called KCNK3), a genetic member of K2P channels, remains an enigma in lung adenocarcinoma (LUAD). Herein, we investigated the pathological process of KCNK3 in proliferation and glucose metabolism of LUAD. The expressions of KCNK3 in LUAD tissues and corresponding adjacent tissues were identified by RNA sequencing, quantitative real-time polymerase chain reaction, western blot, and immunohistochemistry. Gain and loss-of-function assays were performed to estimate the role of KCNK3 in proliferation and glucose metabolism of LUAD. Additionally, energy metabolites of LUAD cells were identified by targeted metabolomics analysis. The expressions of metabolic molecules and active biomarkers associated with AMPK-TXNIP signaling pathway were detected via western blot and immunofluorescence. KCNK3 was significantly downregulated in LUAD tissues and correlated with patients' poor prognosis. Overexpression of KCNK3 largely regulated the process of oncogenesis and glycometabolism in LUAD in vitro and in vivo. Mechanistic studies found that KCNK3-mediated differential metabolites were mainly enriched in AMPK signaling pathway. Furthermore, rescue experiments demonstrated that KCNK3 suppressed proliferation and glucose metabolism via activation of the AMPK-TXNIP pathway in LUAD cells. In summary, our research highlighted an emerging role of KCNK3 in the proliferative activity and glycometabolism of LUAD, suggesting that KCNK3 may be an optimal predictor for prognosis and a potential therapeutic target of LUAD.

C1QTNF6 regulated by miR-29a-3p promotes proliferation and migration in stage I lung adenocarcinoma.

OBJECTIVE: C1QTNF6 has been implicated as an essential component in multiple cellular and molecular preliminary event, including inflammation, glucose metabolism, endothelial cell modulation and carcinogenesis. However, the biological process and potential mechanism of C1QTNF6 in lung adenocarcinoma (LUAD) are indefinite and remain to be elucidated. Therefore, we investigated the interaction among the traits of C1QTNF6 and LUAD pathologic process. METHODS: RT-qPCR and western blot were conducted to determine the expression levels of C1QTNF6. RNA interference and overexpression of C1QTNF6 were constructed to identify the biological function of C1QTNF6 in cellular proliferative, migratory and invasive potentials in vitro. Dual-luciferase reporter assay was applied to identify the possible interaction between C1QTNF6 and miR-29a-3p. Moreover, RNA sequencing analysis of C1QTNF6 knockdown was performed to identify the potential regulatory pathways. RESULTS: C1QTNF6 was upregulated in stage I LUAD tissues compared with adjacent non-cancerous tissues. Concurrently, C1QTNF6 knockdown could remarkably inhibit cell proliferation, migratory and invasive abilities, while overexpression of C1QTNF6 presented opposite results. Additionally, miR-29a-3p may serve as an upstream regulator of C1QTNF6 and reduce the expression of C1QTNF6. Subsequent experiments showed that miR-29a-3p could decrease the cell mobility and proliferation positive cell rates, as well as reduce the migratory and invasive possibilities in LUAD cells via downregulating C1QTNF6. Moreover, RNA sequencing analysis demonstrated that the cytokine-cytokine receptor interaction pathway may participate in the process of C1QTNF6 regulating tumor progression. CONCLUSION: Our study first demonstrated that downregulation of C1QTNF6 could inhibit tumorigenesis and progression in LUAD cells negatively regulated by miR-29a-3p. These consequences could reinforce our awareness and understanding of the underlying mechanism and provide a promising therapeutic target for LUAD.

LncRNA XR_596701 protects H9c2 cells against intermittent hypoxia-induced injury through regulation of the miR-344b-5p/FAIM3 axis.

Long noncoding RNAs (lncRNAs) participate in various biological processes and cardiovascular diseases. Recently, a novel lncRNA XR_596701 was found to be differentially expressed in obstructive sleep apnea (OSA)-induced myocardial tissue compared to normal myocardial tissues. However, the pathological effect and regulatory mechanism of XR_596701 in intermittent hypoxia (IH)-mediated cardiomyocytes damage have not been studied. The subcellular localization of XR_596701 was determined by fluorescence in situ hybridization (FISH). Gene expressions of XR_596701 and miR-344b-5p were detected by quantitative real-time polymerase chain reaction (qRT-PCR) in IH-induced H9c2 cells. Cell proliferation was measured by 5-ethynyl-2'-deoxyuridine (EdU) staining assay. Cell apoptosis was detected by Hoechst 33342/PI staining and immunofluorescence (IF). Apoptotic protein of H9c2 cells was measured by western blot. The direct interaction between XR_596701 and miR-344b-5p as well as miR-344b-5p and Fas apoptotic inhibitory molecule 3 (FAIM3) were examined using dual-luciferase reporter assay. The significance of XR_596701 and miR-344b-5p on cell proliferation and apoptosis was evaluated by using gain-of-function and loss-of-function approaches. XR_596701 was upregulated, while miR-344b-5p downregulated in IH-induced H9c2 cells. Functionally, suppression of XR_596701 and overexpression of miR-344b-5p inhibited cell proliferation and promoted cell apoptosis in H9c2 cells. The roles of XR_596701 were achieved by sponging miR-344b-5p. And the function of miR-344b-5p was reversed by targeting FAIM3. Additionally, FAIM3 mediated IH-induced H9c2 cells damage by XR_596701. XR_596701 was serve as a novel lncRNA that indicated protective roles on proliferation and apoptosis of IH-induced H9c2 cells through the miR-344b-5p/FAIM3 axis.

Comprehensive Analysis of Aquaporin Superfamily in Lung Adenocarcinoma.

Background: Lung adenocarcinoma (LUAD) is the most predomintnt lung cancer subtype with increasing morbidity and mortality. Previous studies have shown that aquaporin (AQP) family genes were correlated with tumor progression and metastasis in several kinds of malignancies. However, their biological behaviors and prognostic values in LUAD have not been comprehensively elucidated. Methods: RNA sequencing and real-time reverse transcription PCR (RT-PCR) were used to assess AQP1/3/4/5 gene expressions in LUAD patients using GEPIA and UALCAN databases. And then Kaplan-Meier analysis, cBioPortal, Metascape, GeneMANIA, TISIDB, and TIMER were utilized to determine the prognostic value, mutation frequency, and immune cell infiltration of AQP family members in LUAD. Results: We found that AQP3 expression was significantly elevated and AQP1 expression was markedly reduced in LUAD patients, whereas the expression levels of AQP4 and AQP5 exhibited no significant changes. The Kaplan-Meier survival analysis indicated that the higher expressions of AQP1/4/5 were related to longer overall survival (OS). Of interest, AQP3 was significantly correlated with the clinical tumor stage and lower AQP3 expression showed favorable prognosis in stage I LUAD patients, which indicated that AQP3 may be a potential prognostic biomarker for patients. Through functional enrichment analysis, the functions of these four AQPs genes were mainly involved in the passive transport by aquaporins, water homeostasis, and protein tetramerization. Moreover, AQP1/3/4/5 expression was strongly associated with tumor-infiltrating lymphocytes (TILs) in LUAD. Conclusion: AQP3 can be used as a prognosis and survival biomarker for stage I LUAD. These findings may provide novel insights into developing molecular targeted therapies in LUAD.

ARHGAP10 inhibits the epithelial-mesenchymal transition of non-small cell lung cancer by inactivating PI3K/Akt/GSK3ß signaling pathway.

BACKGROUND: Rho GTPase activating protein 10 (ARHGAP10) has been implicated as an essential element in multiple cellular process, including cell migration, adhesion and actin cytoskeleton dynamic reorganization. However, the correlation of ARHGAP10 expression with epithelial-mesenchymal transition (EMT) in lung cancer cells is unclear and remains to be elucidated. Herein, we investigated the relationship between the trait of ARHGAP10 and non-small cell lung cancer (NSCLC) pathological process. METHODS: Immunohistochemistry was conducted to evaluate the expression of ARHGAP10 in NSCLC tissues. CCK-8 assays, Transwell assays, scratch assays were applied to assess cell proliferation, invasion and migration. The expression levels of EMT biomarkers and active molecules involved in PI3K/Akt/GSK3ß signaling pathway were examined through immunofluorescence and Western blot. RESULTS: ARHGAP10 was detected to be lower expression in NSCLC tissues compared with normal tissues from individuals. Moreover, overexpression of ARHGAP10 inhibited migratory and invasive potentials of A549 and NCI-H1299 cells. In addition, ARHGAP10 directly mediated the process of EMT via PI3K/Akt/GSK3ß pathway. Meanwhile, activation of the signaling pathway of insulin-like growth factors-1 (IGF-1) reversed ARHGAP10 overexpression regulated EMT in NSCLC cells. CONCLUSION: ARHGAP10 inhibits the epithelial-mesenchymal transition in NSCLC via PI3K/Akt/GSK3ß signaling pathway, suggesting agonist of ARHGAP10 may be an optional remedy for NSCLC patients than traditional opioids.

A systematic review and meta-analysis of immune-mediated liver dysfunction in non-small cell lung cancer.

BACKGROUND: Immune checkpoint inhibitors (ICIs) have been identified as validated medications in non-small cell lung cancer (NSCLC). However, they are often associated with immune-related adverse events (irAEs) including liver dysfunction. Therefore, we conducted a systematic review of the literature and performed a meta-analysis to ascertain overall incidence and risk of immune mediated liver dysfunction in NSCLC patients. METHODS: PubMed, the Cochrane Library, Embase and ClinicalTrials.gov (http://clinicaltrials.gov/) were searched from inception to December 2019. Studies regarding all grade (1-5), high grade (3-5) hepatitis and ALT or AST elevation were included. RESULTS: A total of 11 clinical trials including 7086 patients were selected for further assessment. The overall incidence of ALT elevation, AST elevation and hepatitis for the application of ICIs was 6.18%, 4.99% and 1.09%, respectively. Compared with chemotherapy group, treatment with ICIs had a significantly higher risk of all grade (RR: 7.27, p = 0.001) and high grade (RR: 6.70, p = 0.003) hepatitis. When ICIs combined with chemotherapy, the relative risk of all grade hepatitis was higher than monotherapy group (RR: 7.89, p = 0.044 vs RR: 6.94, p = 0.008). CONCLUSION: The application of ICIs could result in a higher incidence and relative risk of all grade immune-induced liver dysfunction. Moreover, immunotherapy combined with chemotherapy may also increase relative risk of all grade hepatic AEs when compared with monotherapy. Prompt recognition and proper administration is required for clinicians to prevent potentially hepatic deterioration.

The incidence and relative risk of PD-1/PD-L1 inhibitors-related colitis in non-small cell lung cancer: A meta-analysis of randomized controlled trials.

BACKGROUND: The programmed cell death-1 (PD-1)/programmed cell death ligand-1 (PD-L1) inhibitors have shown encouraging merits in non-small cell lung cancer (NSCLC) patients, however, they are often related to potentially fatal immune-related adverse events (irAEs) including colitis. Considering the incidence and characteristics of immune-related colitis may have significant implications for the appropriate utilization of PD-1/PD-L1 inhibitors in clinical practice, we conduct this meta to systematically analyze the correlation between PD-1/PD-L1 inhibitors for the treatment of NSCLC and the incidence of immune-associated colitis. METHODS: Electronic databases including PubMed, Embase, Cochrane Library and ClinicalTrials.gov (http://clinicaltrials.gov/) were searched up to May 2019, clinical trials reporting all grade (1-5), higher grade (3-5) colitis and grade 3-5 diarrhea were included, data were expressed as relative risk (RR), incidence, corresponding p value and 95% confidence intervals (CIs). RESULTS: 9 randomized controlled trials (RCTs) were identified (7 with PD-1 inhibitors [n = 4526]) and 2 with PD-L1 inhibitors [n = 1464]). The overall incidence of PD-1/PD-L1 target agents was 1.40% for all grade colitis, 0.89% for severe colitis, 11.62% for all grade diarrhea and 1.36% for severe diarrhea. Compared with chemotherapy group, the PD-1/PD-L1 inhibitors had a significantly higher risk of all grade (RR: 3.68, p < 0.001) and high-grade (RR: 2.97, p = 0.01) colitis. Additional analysis of relative risk of diarrhea revealed that PD-1/PD-L1 treatment moderately reduce the risk of all grade diarrhea (RR: 0.64, p = 0.03), while the difference was not statistically significant in the risk of grade 3-5 diarrhea (RR: 0.83, p = 0.64). Subgroup analyses showed that the RR of all grade and higher grade colitis in PD-1 inhibitors was more significant (RR: 3.56, p = 0.001 vs RR: 2.98, p = 0.02 respectively). However, there was no appreciable difference in PD-L1 inhibitors (RR: 4.75, p = 0.15 vs RR: 2.85, p = 0.52 respectively). When compared with first-line therapy, second-line therapy associated with a higher risk of all grade colitis than first-line therapy (RR: 3.29, p = 0.006; RR: 4.69, p = 0.026). CONCLUSION: Our meta-analysis indicates when compared with control group, the PD-1/PD-L1 inhibitors may lead to a higher risk of all grade and high grade immune-mediated colitis, but may result in a reduction in all grade diarrhea. PD-1 inhibitors in NSCLC patients, but not PD-L1 inhibitors, increase the risk of all- and high grade colitis. These results suggest that clinicians shall pay more attention to this rare but life-threatening toxic effect.

Photonic band structures solved by a plane-wave-based transfer-matrix method.

Transfer-matrix methods adopting a plane-wave basis have been routinely used to calculate the scattering of electromagnetic waves by general multilayer gratings and photonic crystal slabs. In this paper we show that this technique, when combined with Bloch's theorem, can be extended to solve the photonic band structure for 2D and 3D photonic crystal structures. Three different eigensolution schemes to solve the traditional band diagrams along high-symmetry lines in the first Brillouin zone of the crystal are discussed. Optimal rules for the Fourier expansion over the dielectric function and electromagnetic fields with discontinuities occurring at the boundary of different material domains have been employed to accelerate the convergence of numerical computation. Application of this method to an important class of 3D layer-by-layer photonic crystals reveals the superior convergency of this different approach over the conventional plane-wave expansion method.