Downregulation of tRF-Cys-GCA-029 by hyperglycemia promotes tumorigenesis and glycolysis of diabetic breast cancer through upregulating PRKCG translation.

BACKGROUND: Diabetes mellitus (DM) affects up to one-third of breast cancer (BC) patients. Patients with co-existing BC and DM (BC-DM) have worsened BC prognosis. Nevertheless, the molecular mechanisms orchestrating BC-DM prognosis remain poorly understood. tRNA-derived fragments (tRFs) have been shown to regulate cancer progression. However, the biological role of tRFs in BC-DM has not been explored. METHODS: tRF levels in tumor tissues and cells were detected by tRF sequencing and qRT-PCR. The effects of tRF on BC cell malignancy were assessed under euglycemic and hyperglycemic conditions in vitro. Metabolic changes were assessed by lactate, pyruvate, and extracellular acidification rate (ECAR) assays. Diabetic animal model was used to evaluate the impacts of tRF on BC tumor growth. RNA-sequencing (RNA-seq), qRT-PCR, Western blot, polysome profiling, luciferase reporter assay, and rescue experiments were performed to explore the regulatory mechanisms of tRF in BC-DM. RESULTS: We identified that tRF-Cys-GCA-029 was downregulated in BC-DM tissues and under hyperglycemia conditions in BC cells. Functionally, downregulation of tRF-Cys-GCA-029 promoted BC cell proliferation and migration in a glucose level-dependent manner. tRF-Cys-GCA-029 knockdown also enhanced glycolysis metabolism in BC cells, indicated by increasing lactate/pyruvate production and ECAR levels. Notably, injection of tRF-Cys-GCA-029 mimic significantly suppressed BC tumor growth in diabetic-mice. Mechanistically, tRF-Cys-GCA-029 regulated BC cell malignancy and glycolysis via interacting with PRKCG in two ways: binding to the coding sequence (CDS) of PRKCG mRNA to regulate its transcription and altering polysomal PRKCG mRNA expression to modify its translation. CONCLUSIONS: Hyperglycemia-downregulated tRF-Cys-GCA-029 enhances the malignancy and glycolysis of BC cells. tRF-Cys-GCA-029-PRKCG-glycolysis axis may be a potential therapeutic target against BC-DM.

Outcomes of COVID-19 in multiple myeloma patients treated with daratumumab.

Despite concerns about an increased risk of adverse outcomes following coronavirus disease (COVID-19) in multiple myeloma patients treated with anti-CD38 Abs, the impact of COVID-19 on this group of patients is unclear. We tried to evaluate the clinical outcomes of these patients. We collected data from 1036 patients with multiple myeloma and enrolled 509 cases with COVID-19. We divided enrolled patients into daratumumab or nondaratumumab cohorts based on whether they had received daratumumab-based treatment within 6 months of COVID-19 infection. We applied a propensity score matching method to reduce the bias of baseline characteristics, and then compared the incidence of adverse outcomes between these two cohorts. A total of 117 patients were enrolled in the daratumumab cohort, and 392 patients in the nondaratumumab cohort. After propensity score matching, 204 patients were matched. The proportions of patients who developed COVID-19 pneumonia (59.8% vs. 34.3%, p < 0.001), were hospitalized (33.3% vs. 11.8%, p < 0.001) and developed severe disease (23.5% vs. 6.9%, p = 0.001) were higher in the matched daratumumab cohort. By multivariate analysis, daratumumab exposure was an independent risk factor for severe disease. An ECOG performance status >2 and history of chronic kidney disease were independent risk factors for COVID-19-related mortality among patients who received daratumumab-based therapy. This study suggested that multiple myeloma patients exposed to daratumumab were at a higher risk of adverse outcomes from COVID-19.

Disruption of DNA-PKcs-mediated cGAS retention on damaged chromatin potentiates DNA damage-inducing agent-induced anti-multiple myeloma activity.

BACKGROUND: Targeting DNA damage repair factors, such as DNA-dependent protein kinase catalytic subunit (DNA-PKcs), may offer an opportunity for effective treatment of multiple myeloma (MM). In combination with DNA damage-inducing agents, this strategy has been shown to improve chemotherapies partially via activation of cGAS-STING pathway by an elevated level of cytosolic DNA. However, as cGAS is primarily sequestered by chromatin in the nucleus, it remains unclear how cGAS is released from chromatin and translocated into the cytoplasm upon DNA damage, leading to cGAS-STING activation. METHODS: We examined the role of DNA-PKcs inhibition on cGAS-STING-mediated MM chemosensitivity by performing mass spectrometry and mechanism study. RESULTS: Here, we found DNA-PKcs inhibition potentiated DNA damage-inducing agent doxorubicin-induced anti-MM effect by activating cGAS-STING signaling. The cGAS-STING activation in MM cells caused cell death partly via IRF3-NOXA-BAK axis and induced M1 polarization of macrophages. Moreover, this activation was not caused by defective classical non-homologous end joining (c-NHEJ). Instead, upon DNA damage induced by doxorubicin, inhibition of DNA-PKcs promoted cGAS release from cytoplasmic chromatin fragments and increased the amount of cytosolic cGAS and DNA, activating cGAS-STING. CONCLUSIONS: Inhibition of DNA-PKcs could improve the efficacy of doxorubicin in treatment of MM by de-sequestrating cGAS in damaged chromatin.

Impact of additional cytogenetic aberrations at diagnosis on prognosis of adults patients with Philadelphia chromosome positive acute lymphoblastic leukemia undergoing allogeneic hematopoietic cell transplantation: a retrospective analysis.

Additional chromosomal abnormalities(ACAs) at diagnosis are associated with inferior prognosis in chronic myeloid leukemia. However, the prognostic significance of ACAs in adult patients with Philadelphia Chromosome Positive acute lymphoblastic leukemia (Ph + ALL) receiving TKI-targeted drugs and allogeneic hematopoietic stem cell transplantation(HSCT) is unknown. One hundred thirty-six adult patients with Ph + ALL were included in the study and retrospectively analysed, evaluating the effect of ACAs on outcomes of transplantation. ACAs are observed in 60 cases (44%). ACAs detected in more than 5% of cases were defined as major-route and encompass: +der(22), +der(9), + 8, -7 and complex karyotype. The median follow-up was 26.4 months. In the subgroup analyses of major route ACAs, three-year cumulative incidence of relapse (CIR) and progression-free survival(PFS) are statistically significant in + 8[66.7% vs.23.7%, P = 0.024; 77.8% vs. 23.7%, P = 0.0087], -7[53.8% vs. 23.7%, P = 0.035%; 61.5% vs. 32.9%, P = 0.033], and complex karyotypes[42.9% vs. 23.7%, P = 0.027; 47.6% vs. 23.7%] compared with t(9;22) sole. Additionally, the 3-year CIR for Ph + ALL with + der(22) is 44% vs. 23.7% for t(9;22) sole(P = 0.045). The 3-year overall survival (OS) in the - 7 group is 46.5%, which is statistically significant compared with the other groups(P = 0.001). In multivariate analyses, three years CIR and PFS are statistically significant in + der(22), + 8, -7 and complex karyotype compared with t(9;22) sole(P < 0.05). More importantly, Ph + ALL with - 7 was negatively associated with the rate of 3-year OS(P = 0.012). Thus, ACAs at diagnosis appear to have a significant prognostic impact on transplantation outcomes in patients with Ph + ALL.

Interleukin-32γ promotes macrophage-mediated chemoresistance by inducing CSF1-dependent M2 macrophage polarization in multiple myeloma.

Macrophages (MΦs) are an abundant component in the multiple myeloma (MM) environment and contribute to MM drug resistance. We previously showed that interleukin-32 (IL-32) is highly expressed in MM patients and induces the immunosuppressive function of MΦs. The present study was designed to explore the role of IL-32 in MΦ-mediated MM drug resistance and the underlying mechanism. Our analysis revealed that IL-32 expression was upregulated in relapsed MM patients and associated with CD206+ M2 MΦ infiltration. Subsequently, we found that the most active isoform, IL-32γ, promoted MΦs to protect MM cells from drug-induced apoptosis both in vitro and in vivo. Furthermore, by evaluating many parameters, including surface markers, cytokines, metabolic enzymes and characteristic molecules, IL-32γ was verified to induce the polarization of M2 MΦs, a function that was partly dependent on increasing the expression of colony-stimulating factor 1 (CSF1). Taken together, the results of our study indicate that IL-32γ promotes MΦ-mediated MM drug resistance and modifies MΦs toward the M2 phenotype, providing a crucial theoretical basis for targeted MΦ immunotherapy.

The efficacy of residual plerixafor for second-day stem cell mobilization in multiple myeloma patients.

BACKGROUND: Granulocyte colony-stimulating factor (G-CSF) plus plerixafor has been shown to improve the efficacy of peripheral blood stem cell (PBSC) mobilization, however, due to its high price, the use of plerixafor is limited in China. The purpose of this study was to assess the efficacy of residual plerixafor for second-day stem cell mobilization in multiple myeloma (MM) patients. MATERIALS AND METHODS: In this single-center retrospective study, 69 MM patients received G-CSF + plerixafor to mobilize PBSCs, which were collected from 28 patients only for one day and 41 patients for two days. Some of the patients received residual plerixafor, and PBSCs were collected on the second day. The data on the characteristics, different doses of plerixafor and efficacy of PBSC mobilization were collected and analyzed. RESULTS: After 1 or 2 apheresis procedures, 85.5% of patients collected more than 2 × 106 cells/kg PBSCs. There was no statistically significant difference in the success rate of CD34 + PBSC mobilization with the different doses of plerixafor on the first day, but the higher residual plerixafor dose resulted in better success rates on the second day (P＜0.001). Among the patients who collected PBSCs for two days, the level of the CD34 + cell yield of 24 patients (58.5%) changed better, which was significantly correlated with the dose of residual plerixafor on the second day (P = 0.001). DISCUSSION: These results suggested that the administration of residual plerixafor to mobilize stem cells on the second day is an economical, efficient and clinically feasible method.

Single-Cell Transcriptomic Analysis Reveals BCMA CAR-T Cell Dynamics in a Patient with Refractory Primary Plasma Cell Leukemia.

Chimeric antigen receptor T cell (CAR-T) therapy has revolutionized the clinical treatment of hematological malignancies due to the prominent anti-tumor effects. B cell maturation antigen (BCMA) CAR-T cells have demonstrated promising effects in patients with relapsed/refractory multiple myeloma. However, the dynamics of CAR-T cell proliferation and cytotoxicity in clinical patients remains unexplored. Here, we longitudinally profiled the transcriptomes of 55,488 T cells including CAR-T products, CAR-T cells, and endogenous T cells at the peak and remission phases in a plasma cell leukemia (PCL) patient treated with BCMA CAR-T cells by single-cell transcriptomic analysis. Our results showed distinct CAR-T and endogenous T cell subsets indicating stage-specific expression in proliferation, cytotoxicity, and intercellular signaling pathways. Furthermore, we found that CAR-T cells at peak phase gradually convert to a highly cytotoxic state from a highly proliferative state along a development trajectory. Moreover, re-analysis of a single cell study from CD8+ CD19 CAR-T confirmed our findings. These commonalities suggest conserved mechanisms for CAR-T treatment across hematological malignancies. Taken together, our current study provides insight into CAR-T cell dynamics during CAR-T therapy and proves that both BCMA CAR-T and CD19 CAR-T have similar transcriptional characteristics, especially at the CAR-T peak phase.

Detection and analysis of clinical features of patients with different types of coronavirus disease 2019.

This study was designed to investigate the change of various indexes in patients with different types of coronavirus disease 2019 (COVID-19). Seventy-five patients with COVID-19 were collected from the First Affiliated Hospital, Zhejiang University School of Medicine, and they were classified into moderate, severe and critically severe types according to the disease severity. The basic information, blood routine, pneumonia-related blood indexes, immune-related indexes along with liver, kidney and myocardial indexes in patients with different types were analyzed. The analysis of immune-related indexes showed that the proportions of critically severe patients with abnormal interleukin-2 (IL-2) and IL-4 were higher than those of severe and moderate patients. In addition, the proportion of patients with abnormal total cholesterol increased as the severity of disease increased, and the proportion in critically severe patients was significantly higher than that in moderate patients. The patients with a more severe COVID-19 are older and more likely to have a history of hypertension. With the progression of COVID-19, the abnormal proportion of total white blood cell, neutrophils, lymphocytes, IL-2, IL-4, and total cholesterol increased. The change of these indexes in patients with different COVID-19 types could provide reference for the disease severity identification and diagnosis of COVID-19. In addition, the change in the total cholesterol level suggested that COVID-19 would induce some liver function damage in patients.

Thymic rebound hyperplasia post-chemotherapy mistaken as disease progression in a patient with lymphoma involving mediastinum: a case report and reflection.

BACKGROUND: Chemotherapy can cause thymic atrophy and reduce T-cell output in cancer patients. However, the thymus in young adult patients has regenerative potential after chemotherapy, manifesting as thymic hyperplasia which can be easily mistaken as residual disease or recurrence in patients suffering lymphoma. CASE PRESENTATION: This study reports a case of lymphoma in a young female adult who was initially diagnosed with an anterior mediastinal mass, and was found to have soft tissue occupying the anterior mediastinum repeatedly after chemotherapy, suggesting a lymphoma residue or disease progression. From discussions by a multi-disciplinary team (MDT), the anterior mediastinal mass of the patient was considered unknown and might be thymus tissue or tumor tissue, and it was eventually identified as thymus tissue via histopathology. CONCLUSIONS: The anterior mediastinal mass appearing after chemotherapy in patients with lymphoma can be considered as enlarged thymus, and such phenomenon is frequent in young adult patients who undergo chemotherapy or autologous hematopoietic stem cell transplantation. Additionally, detection of thymic output cells in peripheral blood might be a feasible approach to differentiate thymic hyperplasia from lymphoma.

Dynamics of sediment phosphorus affected by mobile aeration: Pilot-scale simulation study in a hypereutrophic pond.

Controlling the release of phosphorus (P) in sediments is important to prevent eutrophication and harmful algal blooms in water bodies. Here we explored the effect of mobile aerators on the control of P release from sediments in a eutrophic pond. The dissolved oxygen in the water body recovered significantly after six months of aeration, becoming 4.2-5.8 times higher than in the control. The pH and Eh values at the sediment-water interface considerably increased, while the concentration of soluble reactive phosphorus (SRP) in pore water significantly decreased, resulting in the alteration of SRP fluxes from 1.69 mg/m2 d to -53.49 mg/m2 d. Moreover, the inert P in sediments increased by 5.2% of the total P at the end of the study compared with the initial state, and the calcium-bound phosphorus (HCl-P) increased by 96.6%. However, although aeration reduced the concentration of SRP in the water column, the total P concentration was 2.45 times higher than that of the control, and the content of redox-sensitive P (BD-P) in the sediment also increased by 200%. Overall, although mobile aeration can maintain the microenvironment of the sediment interface and increase the inert P content in the sediment to reduce the P flux, it cannot reduce the risk of release of mobile P.

The NEDD4-1 E3 ubiquitin ligase: A potential molecular target for bortezomib sensitivity in multiple myeloma.

E3 ubiquitin ligases primarily determine the substrate specificity of the ubiquitin-proteasome system and play an essential role in the resistance to bortezomib in multiple myeloma (MM). Neural precursor cell-expressed developmentally downregulated gene 4-1 (NEDD4-1, also known as NEDD4) is a founding member of the NEDD4 family of E3 ligases and is involved in the proliferation, migration, invasion and drug sensitivity of cancer cells. In the present study, we investigated the role of NEDD4-1 in MM cells and explored its underlying mechanism. Clinically, low NEDD4-1 expression has been linked to poor prognosis in patients with MM. Functionally, NEDD4-1 knockdown (KD) resulted in bortezomib resistance in MM cells in vitro and in vivo. The overexpression (OE) of NEDD4-1, but not an enzyme-dead NEDD4-1-C867S mutant, had the opposite effect. Furthermore, the overexpression of NEDD4-1 in NEDD4-1 KD cells resensitized the cells to bortezomib in an add-back rescue experiment. Mechanistically, pAkt-Ser473 levels and Akt signaling were elevated and decreased by NEDD4-1 KD and OE, respectively. NEDD4-1 ubiquitinated Akt and targeted pAkt-Ser473 for proteasomal degradation. More importantly, the NEDD4-1 KD-induced upregulation of Akt expression sensitized MM cells to growth inhibition after treatment with an Akt inhibitor. Collectively, our results suggest that high NEDD4-1 levels may be a potential new therapeutic target in MM.

Combination strategies to overcome resistance to the BCL2 inhibitor venetoclax in hematologic malignancies.

Venetoclax has been approved by the United States Food and Drug Administration since 2016 as a monotherapy for treating patients with relapsed/refractory chronic lymphocytic leukemia having 17p deletion. It has led to a breakthrough in the treatment of hematologic malignancies in recent years. However, unfortunately, resistance to venetoclax is inevitable. Multiple studies confirmed that the upregulation of the anti-apoptotic proteins of the B-cell lymphoma 2 (BCL2) family mediated by various mechanisms, such as tumor microenvironment, and the activation of intracellular signaling pathways were the major factors leading to resistance to venetoclax. Therefore, only targeting BCL2 often fails to achieve the expected therapeutic effect. Based on the mechanism of resistance in specific hematologic malignancies, the combination of specific drugs with venetoclax was a clinically optional treatment strategy for overcoming resistance to venetoclax. This study aimed to summarize the possible resistance mechanisms of various hematologic tumors to venetoclax and the corresponding clinical strategies to overcome resistance to venetoclax in hematologic malignancies.

Estimating the remaining atmospheric environmental capacity using a single-box model in a high pollution risk suburb of Chengdu, China.

The atmospheric pollution has been the public attention in recent years. In order to better coordinate economic development and atmospheric environmental management, China introduced the concept of atmospheric environmental capacity (AEC). The remaining atmospheric environmental capacity (RAEC) calculated by existing atmospheric pollution sources and AEC is an important basis for regional development and environmental protection. The RAEC of the high-pollution risk suburb of Chengdu in 2015 was estimated by the single-box model and analyzed on multiple time scales. The results show that the RAEC of SO2 and NO2 in this region is 3299 t/a and 2849 t/a, respectively under the annual time scale. However, in the daily time scale, the RAEC of NO2 is negative for 3 days, that is, there are 3 days with serious air pollution. Therefore, it is not appropriate to plan the industrial area only by relying on annual RAEC. Especially, RAEC displays inter-seasonal and monthly variability. On the one hand, in plain areas with low wind speed and little change in wind direction, achieving the prediction of atmospheric mixing layer height could give early warning of atmospheric pollution events. On the other hand, different management measures are taken on different time scales. On a long timescale, the regional energy structure should be optimized. On seasonal and monthly time scales, the production plans should be adapted to RAEC. On the daily time scale, it mainly deals with the serious atmospheric pollution accident timely.

Metformin and FTY720 Synergistically Induce Apoptosis in Multiple Myeloma Cells.

BACKGROUND/AIMS: Patients with multiple myeloma (MM) invariably relapse with chemotherapy-resistant disease, underscoring the need for new therapeutic options that bypass these resistance mechanisms. Metformin is a widely prescribed antidiabetic drug with direct antitumor activity against various tumor cell lines. FTY720, also known as fingolimod, is an immune-modulating agent approved by the FDA as oral medication to treat the relapsing form of multiple sclerosis (MS). In recent years, FTY720 has attracted attention due to its anti-tumor activity. To explore an optimized combinational therapy, interactions between metformin and FTY720 were examined in MM cells. METHODS: MTT assays were employed to assess the viability of MM cells. An apoptotic nucleosome assay was employed to measure apoptosis. Loss of mitochondrial membrane potential (MMP, ΔΨm) and cellular levels of ROS were measured by flow cytometry. qRT-PCR was used to analyze the expression of mRNAs. Western blotting assays were applied to measure the levels of proteins involved in different signaling pathways. RESULTS: Coadministration of metformin and FTY720 synergistically inhibited the proliferation of MM cells. Increased levels of apoptosis, activation of caspase-3 and cleavage of PARP were detected after cotreatment with metformin and FTY720. These events were associated with modulation of Bcl-2 proteins, loss of MMP, ER stress induction, and inhibition of the PI3K/AKT/mTOR signaling pathway. The metformin/FTY720 regimen markedly induced ROS generation; moreover, apoptosis, ER stress and inhibition of PI3K/AKT/ mTOR were attenuated by the ROS scavenger NAC. CONCLUSIONS: Exposure to metformin in combination with FTY720 potently induces apoptosis in MM cells in a ROS-dependent manner, suggesting that a strategy combining these agents warrants further investigation in MM.

Therapeutic effects of the novel subtype-selective histone deacetylase inhibitor chidamide on myeloma-associated bone disease.

Histone deacetylases are promising therapeutic targets in hematological malignancies. In the work herein, we investigated the effect of chidamide, a new subtype-selective histone deacetylase inhibitor that was independently produced in China, on multiple myeloma and its associated bone diseases using different models. The cytotoxicity of chidamide toward myeloma is due to its induction of cell apoptosis and cell cycle arrest by increasing the levels of caspase family proteins p21 and p27, among others. Furthermore, chidamide exhibited significant cytotoxicity against myeloma cells co-cultured with bone mesenchymal stromal cells and chidamide-pretreated osteoclasts. Importantly, chidamide suppressed osteoclast differentiation and resorption in vitro by dephosphorylating p-ERK, p-p38, p-AKT and p-JNK and inhibiting the expression of Cathepsin K, NFATc1 and c-fos. Finally, chidamide not only prevented tumor-associated bone loss in a disseminated murine model by partially decreasing the tumor burden but also prevented rapid receptor activator of nuclear factor κ-ß ligand (RANKL)-induced bone loss in a non-tumor-bearing mouse model. Based on our results, chidamide exerted dual anti-myeloma and bone-protective effects in vitro and in vivo These findings strongly support the potential clinical use of this drug as a treatment for multiple myeloma in the near future.

The loop rogue wave solutions for the Wadati-Konno-Ichikawa equation.

The first-order rogue wave solution with two arbitrary parameters of the Wadati-Konno-Ichikawa equation is generated based on the Darboux transformation and inverse hodograph transformation. The analyticity of first-order rogue wave solution is studied. A simple analysis shows that the parameter that denotes the amplitude of background wave plays an important role in controlling the analyticity of rogue wave solution. In particular, the rogue wave solution displays a loop-type profile when it is singular, and the general features of loop rogue waves are discussed in detail.

Acupuncture combined with methylcobalamin for the treatment of chemotherapy-induced peripheral neuropathy in patients with multiple myeloma.

BACKGROUND: Chemotherapy-induced peripheral neuropathy (CIPN) seriously affects the quality of life of patients with multiple myeloma (MM) as well as the response rate to chemotherapy. Acupuncture has a potential role in the treatment of CIPN, but at present there have been no randomized clinical research studies to analyze the effectiveness of acupuncture for the treatment of CIPN, particularly in MM patients. METHODS: The MM patients (104 individuals) who met the inclusion criteria were randomly assigned into a solely methylcobalamin therapy group (500 µg intramuscular methylcobalamin injections every other day for 20 days; ten injections) followed by 2 months of 500 µg oral methylcobalamin administration, three times per day) and an acupuncture combined with methylcobalamin (Met + Acu) group (methylcobalamin used the same way as above accompanied by three cycles of acupuncture). Of the patients, 98 out of 104 completed the treatment and follow-ups. There were 49 patients in each group. The evaluating parameters included the visual analogue scale (VAS) pain score, Functional Assessment of Cancer Therapy/Gynecologic Oncology Group-Neurotoxicity (Fact/GOG-Ntx) questionnaire scores, and electromyographic (EMG) nerve conduction velocity (NCV) determinations. We evaluated the changes of the parameters in each group before and after the therapies and made a comparison between the two groups. RESULTS: After 84 days (three cycles) of therapy, the pain was significantly alleviated in both groups, with a significantly higher decrease in the acupuncture treated group (P < 0.01). The patients' daily activity evaluated by Fact/GOG-Ntx questionnaires significantly improved in the Met + Acu group (P < 0.001). The NCV in the Met + Acu group improved significantly while amelioration in the control group was not observed. CONCLUSIONS: The present study suggests that acupuncture combined with methylcobalamin in the treatment of CIPN showed a better outcome than methylcobalamin administration alone. TRIAL REGISTRATION: China Clinical Trials Register (registration no. ChiCTR-INR-16009079 , registration date August 24, 2016).

Semi-rational solutions of the third-type Davey-Stewartson equation.

General dark solitons and mixed solutions consisting of dark solitons and breathers for the third-type Davey-Stewartson (DS-III) equation are derived by employing the bilinear method. By introducing the two differential operators, semi-rational solutions consisting of rogue waves, breathers, and solitons are generated. These semi-rational solutions are given in terms of determinants whose matrix elements have simple algebraic expressions. Under suitable parametric conditions, we derive general rogue wave solutions expressed in terms of rational functions. It is shown that the fundamental (simplest) rogue waves are line rogue waves. It is also shown that the multi-rogue waves describe interactions of several fundamental rogue waves, which would generate interesting curvy wave patterns. The higher order rogue waves originate from a localized lump and retreat back to it. Several types of hybrid solutions composed of rogue waves, breathers, and solitons have also been illustrated. Specifically, these semi-rational solutions have a new phenomenon: lumps form on dark solitons and gradual separation from the dark solitons is observed.

Construction of rational solutions of the real modified Korteweg-de Vries equation from its periodic solutions.

In this paper, we consider the real modified Korteweg-de Vries (mKdV) equation and construct a special kind of breather solution, which can be obtained by taking the limit λj → λ1 of the Lax pair eigenvalues used in the n-fold Darboux transformation that generates the order-n periodic solution from a constant seed solution. Further, this special kind of breather solution of order n can be used to generate the order-n rational solution by taking the limit λ1 → λ0, where λ0 is a special eigenvalue associated with the eigenfunction ϕ of the Lax pair of the mKdV equation. This eigenvalue λ0, for which ϕ(λ0)=0, corresponds to the limit of infinite period of the periodic solution. Our analytical and numerical results show the effective mechanism of generation of higher-order rational solutions of the mKdV equation from the double eigenvalue degeneration process of multi-periodic solutions.