Anti-MUC1 nanobody can synergize the Tamoxifen and Herceptin effects on breast cancer cells by inducing ER, PR and HER2 overexpression.

INTRODUCTION: One of the most pressing concerns associated with breast cancer-targeted therapies is resistance to Tamoxifen and Herceptin. Such drug resistance is usually characterized by reduced expression of certain cell surface receptors. Some biological regimens can induce perceptible overexpression of these receptors in favor of drug responsiveness. MATERIAL AND METHODS: In this research, drug-responsive MCF-7 and SKBR-3, along with drug-resistant MCF-7R (Tamoxifen resistant) and JIMT-1 (Herceptin resistant) breast cancer cell lines in 2D and 3D cultures were exposed to anti-MUC1 nanobody and then assessed for their ER, PR, and HER2 gene and protein expression using qRT-PCR and immunofluorescent staining analyses. Cell viability and the synergistic relationships of combination treatments were determined with MTT assay followed by CompuSyn software. Apoptotic cells were evaluated with Annexin V/propidium Iodide (PI) and acridine orange/ethidium bromide (AO/EB) staining. RESULTS: Anti-MUC1 exposure elevated the expression levels of ER (42 folds), PR (18.5 folds), and HER2 (4.7 folds). As a result of co-treatment, the IC50 levels for Tamoxifen and Herceptin were reduced by up to 10 and 3 folds, respectively. MCF-7R cells responded positively to Tamoxifen, as evidenced by a 5-fold reduction in the IC50 and enhanced apoptosis. CONCLUSION: The ER, PR, and HER2 overexpression after MUC1 blocking could signal drug hypersensitization and facilitate drug resistance management.

Production of novel recombinant anti-EpCAM antibody as targeted therapy for breast cancer.

BACKGROUND: The utilization of monoclonal antibodies (moAbs), an issue correlated with the biopharmaceutical professions, is developing and maturing. Coordinated with this conception, we produced the appealingly modeled anti-EpCAM scFv for breast cancer tumors. METHODS: Afterward cloning and expression of recombinant antibody in Escherichia coli bacteria, the correctness of the desired antibody was checked by western blotting. Flow cytometry was utilized to determine the capacity of the recombinant antibody to append to the desired receptors in the malignant breast cancer (BC)cell line. The recombinant antibody (anti-EpCAM scFv) was examined for preclinical efficacy in reducing tumor growth, angiogenesis, and invasiveness (in vitro- in vivo). FINDINGS: A target antibody-mediated attenuation of migration and invasion in the examined cancer cell lines was substantiated (P-value < 0.05). Grafted tumors from breast cancer in mice indicated significant and compelling suppression of tumor growth and decrement in blood supply in reaction to the recombinant anti-EpCAM intervention. Evaluations of immunohistochemical and histopathological findings revealed an enhanced response rate to the treatment. CONCLUSION: The desired anti-EpCAM scFv can be a therapeutic tool to reduce invasion and proliferation in malignant breast cancer.

Synthesized Anti-HER2 Trastuzumab-MCC-DM1 Conjugate: An Evaluation of Efficacy and Cytotoxicity.

Background: Trastuzumab is a humanized monoclonal antibody that targets site-specifically human epidermal growth factor-2 receptor (HER2) cell surface antigen overexpressed in approximately 20% of human breast carcinomas. Despite its positive therapeutic outcomes, a large proportion of individuals are unresponsive to the treatment with the trastuzumab or develop resistance to it. Objective: To evaluate a chemically synthesized trastuzumab-based antibody-drug conjugate (ADC) to improve the trastuzumab therapeutic index. Methods: The current study explored the physiochemical characteristics of the trastuzumab conjugated to a cytotoxic chemotherapy agent DM1 via Succinimidyl 4-(N-maleimidomethyl) cyclohexane-1-carboxylate (SMCC) linker, created in our earlier study, using SDS-PAGE, UV/VIS, and RP-HPLC analyses. The antitumor effects of the ADCs were analyzed using MDA-MB-231 (HER2-negative) and SK-BR-3 (HER2-positive) cell lines utilizing in vitro cytotoxicity, viability, and binding assays. Three different formats of a HER2-targeting agent: trastuzumab, synthesized trastuzumab-MCC-DM1, and commercially available drug T-DM1 (Kadcyla®) were compared. Results: UV-VIS spectroscopic analysis showed that the trastuzumab-MCC-DM1 conjugates, on average, entailed 2.9 DM1 payloads per trastuzumab. A free drug level of 2.5% was determined by RP-HPLC. The conjugate appeared as two bands on a reducing SDS-PAGE gel. MTT viability assay showed that conjugating trastuzumab with DM1 significantly improved the antiproliferative effects of this antibody in vitro. Importantly, the evaluations using LDH release and cell apoptosis assays confirmed that trastuzumab maintains its ability to induce cell death response while conjugating with the DM1. The binding efficiency of trastuzumab-MCC-DM1 was comparable to that of the naked trastuzumab. Conclusion: Trastuzumab-MCC-DM1 was found effective against HER2+ tumors. The potency of this synthesized conjugate brings it closer to the commercially available T-DM1.

Development of a MET-targeted single-chain antibody fragment as an anti-oncogene targeted therapy for breast cancer.

The usage of monoclonal antibodies (mAbs) and antibody fragments, as a matter associated with the biopharmaceutical industry, is increasingly growing. Harmonious with this concept, we designed an exclusive modeled single-chain variable fragment (scFv) against mesenchymal-epithelial transition (MET) oncoprotein. This scFv was newly developed from Onartuzumab sequence by gene cloning, and expression using bacterial host. Herein, we examined its preclinical efficacy for the reduction of tumor growth, invasiveness and angiogenesis in vitro and in vivo. Expressed anti-MET scFv demonstrated high binding capacity (48.8%) toward MET-overexpressing cancer cells. The IC50 value of anti-MET scFv against MET-positive human breast cancer cell line (MDA-MB-435) was 8.4 µg/ml whereas this value was measured as 47.8 µg/ml in MET-negative cell line BT-483. Similar concentrations could also effectively induce apoptosis in MDA-MB-435 cancer cells. Moreover, this antibody fragment could reduce migration and invasion in MDA-MB-435 cells. Grafted breast tumors in Balb/c mice showed significant tumor growth suppression as well as reduction of blood-supply in response to recombinant anti-MET treatment. Histopathology and immunohistochemical assessments revealed higher rate of response to therapy. In our study, we designed and synthetized a novel anti-MET scFv which could effectively suppress MET-overexpressing breast cancer tumors.

Recombinant nanobody against MUC1 tandem repeats inhibits growth, invasion, metastasis, and vascularization of spontaneous mouse mammary tumors.

Alteration in glycosylation pattern of MUC1 mucin tandem repeats during carcinomas has been shown to negatively affect adhesive properties of malignant cells and enhance tumor invasiveness and metastasis. In addition, MUC1 overexpression is closely interrelated with angiogenesis, making it a great target for immunotherapy. Alongside, easier interaction of nanobodies (single-domain antibodies) with their antigens, compared to conventional antibodies, is usually associated with superior desirable results. Herein, we evaluated the preclinical efficacy of a recombinant nanobody against MUC1 tandem repeats in suppressing tumor growth, angiogenesis, invasion, and metastasis. Expressed nanobody demonstrated specificity only toward MUC1-overexpressing cancer cells and could internalize in cancer cell lines. The IC50 values (the concentration at which the nanobody exerted half of its maximal inhibitory effect) of the anti-MUC1 nanobody against MUC1-positive human cancer cell lines ranged from 1.2 to 14.3 nm. Similar concentrations could also effectively induce apoptosis in MUC1-positive cancer cells but not in normal cells or MUC1-negative human cancer cells. Immunohistochemical staining of spontaneously developed mouse breast tumors prior to in vivo studies confirmed cross-reactivity of nanobody with mouse MUC1 despite large structural dissimilarities between mouse and human MUC1 tandem repeats. In vivo, a dose of 3 µg nanobody per gram of body weight in tumor-bearing mice could attenuate tumor progression and suppress excessive circulating levels of IL-1a, IL-2, IL-10, IL-12, and IL-17A pro-inflammatory cytokines. Also, a significant decline in expression of Ki-67, MMP9, and VEGFR2 biomarkers, as well as vasculogenesis, was evident in immunohistochemically stained tumor sections of anti-MUC1 nanobody-treated mice. In conclusion, the anti-MUC1 tandem repeat nanobody of the present study could effectively overcome tumor growth, invasion, and metastasis.

Engineered hypoxia-responding Escherichia coli carrying cardiac peptide genes, suppresses tumor growth, angiogenesis and metastasis in vivo.

Development of engineered non-pathogenic bacteria, capable of expressing anti-cancer proteins under tumor-specific conditions, is an ideal approach for selectively eradicating proliferating cancer cells. Herein, using an engineered hypoxia responding nirB promoter, we developed an engineered Escherichia coli BW25133 strain capable of expressing cardiac peptides and GFP signaling protein under hypoxic condition for spatiotemporal targeting of mice mammary tumors. Following determination of the in vitro cytotoxicity profile of the engineered bacteria, selective accumulation of bacteria in tumor microenvironment was studied 48 h after tail vein injection of 108 cfu bacteria in animals. For in vivo evaluation of antitumoral activities, mice with establishment mammary tumors received 3 consecutive intravenous injections of transformed bacteria with 4-day intervals and alterations in expression of tumor growth, invasion and angiogenesis specific biomarkers (Ki-67, VEGFR, CD31and MMP9 respectively), as well as fold changes in concentration of proinflammatory cytokines were examined at the end of the 24-day study period. Intravenously injected bacteria could selectively accumulate in tumor site and temporally express GFP and cardiac peptides in response to hypoxia, enhancing survival rate of tumor bearing mice, suppressing tumor growth rate and expression of MMP-9, VEGFR2, CD31 and Ki67 biomarkers. Applied engineered bacteria could also significantly reduce concentrations of IL-1ß, IL-6, GC-SF, IL-12 and TNF-α proinflammatory cytokines while increasing those of IL-10, IL-17A and INF-γ. Overall, administration of hypoxia-responding E. coli bacteria, carrying cardiac peptide expression construct could effectively suppress tumor growth, angiogenesis, invasion and metastasis and enhance overall survival of mice bearing mammary tumors.

Development of a recombinant anti-VEGFR2-EPCAM bispecific antibody to improve antiangiogenic efficiency.

Tumor progression and metastasis, especially in invasive cancers (such as triple-negative breast cancer [TNBC]), depend on angiogenesis, in which vascular epithelial growth factor (VEGF)/vascular epithelial growth factor receptor [1] has a decisive role, followed by the metastatic spread of cancer cells. Although some studies have shown that anti-VEGFR2/VEGF monoclonal antibodies demonstrated favorable results in the clinic, this approach is not efficient, and further investigations are needed to improve the quality of cancer treatment. Besides, the increased expression of epithelial cell adhesion molecule (EpCAM) in various cancers, for instance, invasive breast cancer, contributes to angiogenesis, facilitating the migration of tumor cells to other parts of the body. Thus, the main goal of our study was to target either VEGFR2 or EpCAM as pivotal players in the progression of angiogenesis in breast cancer. Regarding cancer therapy, the production of bispecific antibodies is easier and more cost-effective compared to monoclonal antibodies, targeting more than one antigen or receptor; for this reason, we produced a recombinant antibody to target cells expressing EpCAM and VEGFR2 via a bispecific antibody to decrease the proliferation and metastasis of tumor cells. Following the cloning and expression of our desired anti-VEGFR2/EPCAM sequence in E. coli, the accuracy of the expression was confirmed by Western blot analysis, and its binding activities to VEGFR2 and EPCAM on MDA-MB-231 and MCF-7 cell lines were respectively indicated by flow cytometry. Then, its anti-proliferative potential was indicated by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) and apoptosis assay to evaluate inhibitory effects of the antibody on tumor cells. Subsequently, the data indicated that migration, invasion, and angiogenesis were inhibited in breast cancer cell lines via the bispecific antibody. Furthermore, cytokine analysis indicated that the bispecific antibody could moderate interleukin 8 (IL-8) and IL-6 as key mediators in angiogenesis progression in breast cancer. Thus, our bispecific antibody could be considered as a promising candidate tool to decrease angiogenesis in TNBC.

The Role of Mucosal Immunity and Recombinant Probiotics in SARS-CoV2 Vaccine Development.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV2), causing the 2019 novel coronavirus disease (COVID-19), was introduced by WHO (World Health Organization) as "pandemic" in March 2020. According to WHO, thus far (23 November 2020) 58,425,681 infected cases including 1,385,218 deaths have been reported worldwide. In order to reduce transmission and spread of this lethal virus, attempts are globally being made to develop an appropriate vaccine. Intending to neutralize pathogens at their initial entrance site, protective mucosal immunity is inevitably required. In SARS-CoV2 infection and transmission, respiratory mucosa plays a key role; hence, apparently mucosal vaccination could be a superior approach to elicit mucosal and systemic immune responses simultaneously. In this review, the advantages of mucosal vaccination to control COVID-19 infection, limitations, and outcomes of mucosal vaccines have been highlighted. Considering the gut microbiota dysregulation in COVID-19, we further provide evidences on utilization of recombinant probiotics, particularly lactic acid bacteria (LAB) as vaccine carrier. Their intrinsic immunomodulatory features, natural adjuvanticity, and feasible expression of relevant antigen in the mucosal surface make them more appealing as live cell factory. Among all available platforms, bioengineered probiotics are considered as the most affordable, most practical, and safest vaccination approach to halt this emerging virus.

Dual in vitro invasion/migration suppressing and tamoxifen response modulating effects of a recombinant anti-ALCAM scFv on breast cancer cells.

It has been shown that overexpression of activated leukocyte cell adhesion molecule (ALCAM) is involved in development of resistance to tamoxifen therapy and promotion of cell invasion, migration and metastasis in ER+ breast cancer cells. Thus, we hypothesized that blockade of ALCAM interconnections with antibodies could be an effective approach for reversing mentioned negative events associated with ALCAM overexpression in breast cancer cells. Here, an anti-ALCAM scFv was recombinantly expressed and used throughout study for examination of the putative anticancer effects of ALCAM blockade. The anti-ALCAM scFv coding sequence was obtained from GenBank database and after addition of a 6× His-tag moiety, signal peptide and flanking sequences, the whole construct was expressed in Escherichia coli. Tamoxifen resistant MCF7 cells were then pretreat for 24 hours with purified recombinant anti-ALCAM scFv prior to administration of tamoxifen. In parallel, the cytotoxicity profile of anti-ALCAM scFv and tamoxifen co-treatments against tamoxifen resistant and sensitive MCF7 cell lines was also evaluated using CompuSyn software. The invasion/migration inhibitory effects of anti-ALCAM scFv on MDA-MB-231 cells were also evaluated. Pretreatment with anti-ALCAM scFv could successfully enhance anti-proliferative effects of tamoxifen against resistant MCF-7 cell lines. Furthermore, the combination of 19.2:1 of tamoxifen to anti-ALCAM scFv demonstrated synergistic cell inhibitory effect against tamoxifen resistant MCF7 cell lines. Also, incubating MDA-MB-231 cell lines with anti-ALCAM scFv resulted in a 30% and 25% reduction in number of invaded and migrated cells respectively. Overall, application of anti-ALCAM scFv could significantly suppress cancer cells metastasis in vitro and modulate tamoxifen resistant ER+ MCF7 cell line's sensitivity to tamoxifen. SIGNIFICANCE OF THE STUDY: Acquisition of resistance to tamoxifen therapy is one of the major challenges associated with cancer chemotherapy, gradually turning a responsive tumour into a refractory more invasive one which ultimately ends in disease progression and relapse. Here, we reported expression of an anti-ALCAM scFv, capable of increasing the sensitivity of tamoxifen resistant ER+ MCF-7 cells to tamoxifen therapy following a 24-hour pretreatment period. In addition, we demonstrated that the anti-ALCAM scFv monotherapy was also capable of suppressing invasion and migration of MDA-MB-231 cells in Boyden chamber assays.

Development of an anti-CD45RA-quantum dots conjugated scFv to detect leukemic cancer stem cells.

Leukemic cancer stem cells (LSCs), aberrantly overexpressing CD45RA are among the major causes of relapse following chemotherapy in patients with acute myeloid leukemia and serve as a highly sensitive marker for predicting relapse occurrence following chemotherapy. The main purpose of current study was to develop a sensitive approach for detecting LSCs based on a conjugate of an anti-CD45 scFv and quantum dot. The variable light and heavy chain sequences of a recently developed anti-CD45RA monoclonal antibody were derived from hybridoma cells and PCR amplified to construct scFv. Following insertion of scFv gene into a pET32a-lic vector and expression in Escherichia coli and purification, the purified scFv, was conjugated with carbon dots (C dots) and used for the detection of CD45RA +cells while CD45RA-cells served as negative control. Subsequently, Functional activity of the conjugate was analyzed by flow cytometry and ICC to detect the cell surface antigen binding and detection ability. Based on results, purified CD45RA scFv conjugated C dots could specifically recognize CD45RA positive cells, but not any CD45RA negative ones. In conclusion, here we developed a low-cost but very efficient approach for detection of CD45RA positive cells including LSCs.

Evaluation the potential of recombinant anti-CD3 nanobody on immunomodulatory function.

T cells are the most predominant effector cells in immune-mediated elimination of cancer and circumventing tumor progression. Among various approaches, T cells activation by specific antibodies independently of their TCR specificity, is considered as an effective approach to circumvent tumor progression. The most common surface marker for all T cells which is crucial for T cell activation is regarded as CD3. Therefore, the goal of our study was to evaluate the preclinical efficacy of recombinant anti-CD3 nanobody. To this end, anti-CD3 sequence, was PCR amplified, following cloning and expression in E.coli and purification, the purified nanobody with a molecular weight of ∼17 kDa was confirmed by western blot. Furthermore, flow cytometry analysis demonstrated that purified nanobody could bind to CD3 on Jurkat cell line. Subsequently, results from inoculation of 3 µg/g of nanobody to tumor bearing balb/c mice indicate inhibition of tumor growth. Furthermore, circulating levels of tumoricidal cytokines such as IL-2 and IFNγ were raised whereas tolerogenic cytokines such as IL-4, 6 and 10 were decreased at the end of the treatment. Moreover, IHC analysis confirmed the presence and also the percentage of TILs in tumor sites in response to anti-CD3 therapy. Hence, our results suggest that the purified anti-CD3 nanobody may become a promising candidate for targeting and activating CTLs to induce anti-tumor responses and may provide groundwork for future studies involving other kind of cancers.

The antiproliferative effects of cold atmospheric plasma-activated media on different cancer cell lines, the implication of ozone as a possible underlying mechanism.

Recent studies have proven several promising anticancer activities for cold atmospheric plasma (CAP) against a wide range of cancer cells in vitro. Recently, media treated with CAP have also found to effectively eradicate cancer cells similar to the CAP. Based on advantages, many researchers prefer to apply CAP-activated media (PAM) as an alternative to cap in the treatment of cancer. However, less has been achieved regarding the anticancer effects and anticancer mechanisms of PAM. Investigating the selective anticancerous activities of PAM, the viability of SKBR3, MCF7, ASPC-1, A-549, G-292, and SW742 cancer cell lines, as well as normal human skin fibroblasts (FMGB-1) and MCF10A cells in relation to the media activation time, and the length of exposure was studied. Also, we examined the concentration of ozone in media as a function to CAP activation time since recent studies have proposed ozone as a pivotal reactive species in the induction of cell death. Based on the result, both increasing the duration of media activation time and the length of exposure to PAM could significantly increase the anticancer activity. Nevertheless, the cytotoxicity on normal cells was either not affected or slightly increased. Among the six tested cancer cell lines, SW742 was the most resistant and SKBR3 the most susceptible cancer cell lines to PAM. Also, increasing duration of treatment with CAP resulted in a significant rise in O3 concentration levels in media. Overall, these results suggest PAM, as a promising tool in the treatment of different cancers and O 3 formation as a probable underlying mechanism.

eNOS gene Glu298Asp variant confer risk in sudden sensorineural hearing loss.

BACKGROUND: Sudden sensorineural hearing loss (SSNHL) causes the loss of hearing of 30 dB or greater on at least three contiguous frequencies. It is known to be a multifactorial disease which the exact cause is unknown, rendering it as an idiopathic disorder of patients. AIMS/OBJECTIVES: This study aims to shed further light on pathogenesis of this disease by studying the association between eNOS gene Glu298Asp polymorphism and VDR gene FokI polymorphism with SSNHL in Iranian population. MATERIAL AND METHODS: This study involves a total of 77 cases and 100 controls, with patients inflicted with SSNHL categorized in case group and healthy subjects as control group. Genotyping of the VDR and eNOS genes was conducted by the polymerase chain reaction and restriction fragment length polymorphism (PCR-RFLP) method. RESULTS: Our results showed a statistically significant association between genotype frequencies of eNOS gene Glu298Asp polymorphism in case group compared to healthy individuals in the control group (p = .01). Also, TT genotype was significantly the most prevalent genotype in case group in comparison to control group (TT vs GT + GG, OR = 3.5; 95% CI = 1.18-11.79). On the other hand, analysis of VDR gene FokI polymorphism frequencies showed no statistically significant association with SSNHL. CONCLUSIONS AND SIGNIFICANCE: Our findings showed a significant association between the eNOS gene Glu298Asp polymorphism and SSNHL in the Iranian population; and "TT" genotype might be considered as a risk factor for SSNHL.

Self-filling microwell arrays (SFMAs) for tumor spheroid formation.

Tumor spheroid formation in microwell arrays is a promising approach for high-throughput screening of chemotherapeutic agents. This method offers the advantage of better mimicking the complexities of tumors as compared to conventional monolayer culture systems. However, using these technologies to their full potential is hindered by the inability to seed the cells within the wells uniformly and with high yield and reproducibility. Moreover, standard manufacturing approaches for fabrication of microwell arrays rely on lithography and etching techniques, which are costly, labor-intensive, and time-consuming. Herein, we report on the development of self-filling microwell arrays (SFMAs) in which cells are directed from a loading chamber to microwells using inclined guiding channels. The SFMAs are fabricated by replica molding of three-dimensionally (3D) printed molds in agarose. We characterize the fabrication process, demonstrate the ability to culture breast adenocarcinoma MCF-7 and glioma U87 in SFMAs and perform drug toxicity studies. We envision that the proposed innovative approach opens avenues of opportunities for high-throughput three-dimensional cell culture for drug screening and disease modeling.

Significant Role of MUC1 in Development of Resistance to Currently Existing Anti-cancer Therapeutic Agents.

As an extensively glycosylated transmembrane protein of epithelium, Mucin1 (MUC1) mostly protects cells from tensions induced by external milieu. Physiologically, during stress condition, MUC1 separates into MUC1-N and MUC1-C moieties, resulting in transduction of inward survival signals, essential for maintaining cell's functionality. Recent studies have proposed a significant correlation between MUC1 overexpression and amplification of cancer cell's proliferation and metastasis through modulation of multiple signaling pathways and cell-cell and cell-matrix interactions. It has been shown that MUC1- Cytoplasmic Domain (MUC1-CD) accelerates development of resistance to several anti-cancer therapeutic agents including bortezomib, trastuzumab and tamoxifen. Furthermore, MUC1-CD is also involved in promoting expression of multi drug resistance (MDR) genes and finally, silencing MUC1 expression was together with resensitization of human epidermal growth factor receptor 2 positive (HER2+) and/or estrogen receptor (ER+) positive breast cancer cells to bortezomib, trastuzumab and tamoxifen respectively. In this review, we briefly describe the role of MUC1 proto-oncogene in cancer cell's survival, tumor progression and metastasis and then continue with mentioning the mechanisms through which MUC1 induce resistance to various currently existing therapeutic agents in market including bortezomib, trastuzumab and tamoxifen.

Blinatumomab provoked fatal heart failure.

Mentioned in Blinatumomab (Blincyto®) clinical safety report, a 5 year old boy with acute lymphoblastic leukemia (ALL) receiving Blincyto® with the concentration of 30µg/m2/day on the fourth day of therapy developed both Cytokine Release Syndrome (CRS) and Tumor Lysis Syndrome (TLS). Aspartate aminotransferase (AST), Alanine aminotransferase (ALT) and Bilirubin peaks were 18, 7 and 8 folds more than upper normal limit (UNL) respectively. However, albumin was reduced to approximately half of the lower Normal limit (LNL). Although Blincyto® administration was immediately withdrawn, he expired in the day 10 due to a fatal cardiac failure. Based on evidence, FDA concluded that CRS was the main cause of death in this patient. Evoking evidence now propose that aberrant pro-inflammatory cytokines secretion, the hallmark of CRS, and subsequent elevation in nitric oxide (NO) can result in both inotropic and chronotropic alterations in myocardial excitation-contraction coupling, myocardial contractility suppression, desensitization of ß-adrenergic receptors stimulation, development of acute cardiac failure and death. The probably neglecting point here is that TLS itself can also develop life threatening conditions including sudden cardiac failure through induction of hypocalcemia, hyperkalemia and hyperuricemia, making CRS monitoring and proper required supportive interventions more complex. Here, first we enumerate probable mechanisms through which CRS results in development of fatal cardiac failure and then explain the possible neglected role of TLS in development of the fatal cardiac failure.