Cytotoxic Effects Of Chemotherapy Research Articles

Effects of FOLFOX Chemotherapy on Tumor Oxygenation and Perfused Vasculature: An InVivo Study by OpticalTechniques.

The effects of cytotoxic chemotherapy on tumor vasculature and oxygenation are in the focus of modern investigations becausevascular structure and distribution of oxygen influence tumor behavior and treatment response. The aim of ourstudywas to monitor changes in the vascular component of colorectal tumor xenografts induced by a clinical combination of chemotherapy drugs FOLFOX invivo using two complementary techniques: diffuse reflectance spectroscopy (DRS) and optical coherence tomography-based microangiography (OCT-MA). These techniques revealed a slower decrease in tumor blood oxygenation in treated tumors as compared to untreated ones, faster suppression of tumor vasculature perfusion and increase in water content as a result of treatment, and decrease in total hemoglobin in untreated tumors. Immunohistochemical analysis of hypoxia-inducible factor HIF-2α detected tissue hypoxia as a consequence of inappropriate oxygen supply in the treated tumors. The obtained results show the prospects for monitoring of treatment efficacy using DRS and OCT-MA.

Cardiac toxicity of HER-2 targeting antibody-drug conjugates: overview and clinical implications.

Antibody-drug conjugates (ADCs) have recently emerged as a promising therapeutic option that combine the specificity of monoclonal antibodies and the cytotoxic effect of chemotherapy. With numerous ADCs approved and on the market, a particular concern of ADCs that target HER-2 has been their cardiac side effects, in view of the crucial role of HER-2 in cardiac development and physiology. While rarely toxic and generally safe, numerous publications have outlined the consistent association of trastuzumab emtansine (T-DM1) and trastuzumab deruxtecan (T-DXd) with the development of cardiac toxicity. Despite not being clinically relevant in most cases, cardiac baseline evaluation, monitoring and early detection of cardiac adverse events remain pivotal with HER-2 targeting ADCs. This review aims to summarize and better characterize the complete cardiac toxicity profile of HER-2 ADCs, with the goal of improving clinical understanding of this adverse event, leading to better recognition, monitoring and management.

Glioblastoma Multiforme: Sensitivity to Antimicrobial Peptides LL-37 and PG-1, and Their Combination with Chemotherapy for Predicting the Overall Survival of Patients.

Background/Objectives: Glioblastomas (GBMs) are the most malignant and intractable of all cancers, with an unfavorable clinical prognosis for affected patients. The objective was to analyze the sensitivity of GBM cells to the antimicrobial peptides (AMPs) cathelicidin (LL-37) and protegrin-1 (PG-1), both alone and in combination with chemotherapy, to predict overall survival (OS) in the patients. Methods: The study was conducted on 27 GBM patients treated in the neurosurgical department of the Almazov Medical Research Centre (Saint Petersburg, Russia) from 2021 to 2024. The cytotoxic effects of chemotherapy, AMPs, and their combinations on brain tumor cells were assessed by an MTT assay using a 50% inhibitory concentration (IC50). Results: In GBM cells from the patients, LL-37 and PG-1 exhibited strong anticancer effects, surpassing those of chemotherapy drugs. These LL-37 and PG-1 anticancer effects were associated with a statistically significant increase in life expectancy and OS in GBM patients. These findings were confirmed by experiments on rats with C6 glioma, where the intranasal administration of LL-37 (300 μM) and PG-1 (600 μM) increased the life expectancy of the animals to 69 and 55 days, respectively, compared to 24 days in the control group (HR = 4.139, p = 0.0005; HR = 2.542, p = 0.0759). Conclusions: Additionally, the combination of LL-37 and PG-1 with chemotherapy drugs showed that a high IC50 of LL-37 with cisplatin (cutoff > 800 μM) in GBM cells was associated with increased life expectancy (19 vs. 5 months, HR = 4.708, p = 0.0101) and OS in GBM patients. These combinations could be used in future GBM treatments.

Effects of Cytotoxic Chemotherapy and Endocrine Therapy on Hemodynamics and Oxygen Uptake During Handgrip Exercise in Patients Treated for Breast Cancer

Breast cancer therapies can alter skeletal muscle blood flow during exercise and decrease mitochondrial content and function. However, the impact of different therapies on the variables determining oxygen transport and utilization during submaximal exercise remain unknown. We tested the hypothesis that both chemotherapy and endocrine therapy would decrease blood flow and increase deoxygenated [hemoglobin+myoglobin] (HHb) with an unchanged oxygen uptake (VȮ2) during exercise compared to healthy controls. Participants were healthy females (CTRL; n = 5; age: 58 ± 8 years; body mass index: 25 ± 4 kg/m2) or female patients diagnosed with stage I-III breast cancer comprising three groups: 1) two to five weeks post completion of cytotoxic chemotherapy (CHEMO; n = 5; age: 55 ± 8 years; body mass index, BMI: 30 ± 4 kg/m2); 2) currently on endocrine therapy ≥5 months (ENDO; n = 9; age: 59 ± 7 years; BMI: 27 ± 6 kg/m2); and 3) completed cytotoxic chemotherapy and currently on endocrine therapy ≥5 months (CHEMO+ENDO; n = 8; age: 58 ± 6 years; BMI: 26 ± 5 kg/m2). Forearm blood flow, HHb, and estimated VȮ2 were measured during the final minute of a 3-minute intermittent isometric handgrip exercise at 3 and 6 kg. There were no group or group x intensity effects (all p<0.18) for forearm blood flow (CTRL: 260 ± 33 ml/min; CHEMO: 407 ± 96 ml/min; ENDO: 309 ± 140 ml/min; CHEMO+ENDO: 313 ± 86 ml/min), HHb (CTRL: 134 ± 58 μM; CHEMO: 73 ± 36 μM; ENDO: 118 ± 67 μM; CHEMO+ENDO: 101 ± 25 μM), or estimated VȮ2 (CTRL: 59 ± 28 ml/min; CHEMO: 48 ± 21 ml/min; ENDO: 54 ± 28 ml/min; CHEMO+ENDO: 53 ± 21 ml/min). These findings indicate that chemotherapy and endocrine therapy do not affect muscle hemodynamics and oxidative metabolism during submaximal handgrip exercise. This study was funded, in part, by the Veterans Affairs Clinical Science Research and Career Development Award (IK2 CX002114). This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Abstract 1882: DXC024, a novel anti-TROP2/EGFR bispecific antibody and tubulysin conjugate, for targeted treatment of highly TROP2- or EGFR-expressing tumors

Abstract Antibody drug conjugates (ADCs) which combine the precision of targeted therapy with the cytotoxic effects of chemotherapy have become a promising drug class in cancer therapy. Epidermal growth factor receptor (EGFR) is overexpressed in a wide diversity of epithelial tumors, promoting cell proliferation and survival pathways. Tumor-associated calcium signal transducer 2 (Trop2) is also expressed in a wide range of solid tumors and has been used as a transport gate for cytotoxic agents into cells in antibody-drug conjugate constructions for clinic applications. However, the approved Trop2 ADC, sacituzumab govitecan, only showed an objective response rate (ORR) of 17% and median OS of 9.5 months for lung cancers. In addition, both EGFR-ADC and Trop2-ADC had exhibited strong side effects in clinical trials due to their expression on some normal tissues, such as skin, mouth, eyes, etc. We generated bispecific Fab/scFv antibodies targeting both TROP2 and EGFR using the knob-into-hole technology, which presumably have wider efficacy, less on-target toxicity in comparison to the ADCs constructed based on the fully individual EGFR and Trop2 IgG antibodies having strong affinity to either EGFR or Trop2 antigens. Indeed, many of generated anti-TROP2/EGFR BsAbs showed strong binding activity in TROP2highEGFRhigh cells and demonstrated over 60% internalization rate within 60 min in vitro. The selected BsAbs were subsequently conjugated with tubulysin B analogs with varieties of peptidyl linkers to generate bispecific ADC (DXC024) candidates, two of which exhibited strong killing activity in A431, MDA-MB-468, Calu3, MCF-7 cells with IC50 of single to ten digital pM. In vivo, they showed very good durable antitumor response at dose as low as 4.6 mg/Kg for one injection in Calu3 (TROP2highEGFRmoderate) xenograft model, and demonstrated enhanced anti-tumor efficacy in comparison to those of the same payload conjugated to the monoclonal TROP2 or EGFR ADCs. These results indicated that DXC024 would be a promising ADC candidate for targeted treatment of highly either TROP2- or EGFR-expressing tumors. Citation Format: Jingjing Zhu, Junxiang Jia, Huihui Guo, Xiangfei Kong, Yong Du, Zhicang Ye, Lingli Zhang, Yongxiang Chen, Lu Bai, Yunxia Zheng, Wei Zheng, Jun Zheng, Juan Wang, Wenjun Li, Yuanyuan Huang, Zhongliang Fan, Mengmeng Liu, Binbin Chen, Meng Dai, Fang Du, Miaomiao Chen, Zhixiang Guo, Qingliang Yang, Robert Y. Zhao. DXC024, a novel anti-TROP2/EGFR bispecific antibody and tubulysin conjugate, for targeted treatment of highly TROP2- or EGFR-expressing tumors [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 1882.

Aberrant MET Receptor Tyrosine Kinase Signaling in Glioblastoma: Targeted Therapy and Future Directions.

Brain tumors represent a heterogeneous group of neoplasms characterized by a high degree of aggressiveness and a poor prognosis. Despite recent therapeutic advances, the treatment of brain tumors, including glioblastoma (GBM), an aggressive primary brain tumor associated with poor prognosis and resistance to therapy, remains a significant challenge. Receptor tyrosine kinases (RTKs) are critical during development and in adulthood. Dysregulation of RTKs through activating mutations and gene amplification contributes to many human cancers and provides attractive therapeutic targets for treatment. Under physiological conditions, the Met RTK, the hepatocyte growth factor/scatter factor (HGF/SF) receptor, promotes fundamental signaling cascades that modulate epithelial-to-mesenchymal transition (EMT) involved in tissue repair and embryogenesis. In cancer, increased Met activity promotes tumor growth and metastasis by providing signals for proliferation, survival, and migration/invasion. Recent clinical genomic studies have unveiled multiple mechanisms by which MET is genetically altered in GBM, including focal amplification, chromosomal rearrangements generating gene fusions, and a splicing variant mutation (exon 14 skipping, METex14del). Notably, MET overexpression contributes to chemotherapy resistance in GBM by promoting the survival of cancer stem-like cells. This is linked to distinctive Met-induced pathways, such as the upregulation of DNA repair mechanisms, which can protect tumor cells from the cytotoxic effects of chemotherapy. The development of MET-targeted therapies represents a major step forward in the treatment of brain tumours. Preclinical studies have shown that MET-targeted therapies (monoclonal antibodies or small molecule inhibitors) can suppress growth and invasion, enhancing the efficacy of conventional therapies. Early-phase clinical trials have demonstrated promising results with MET-targeted therapies in improving overall survival for patients with recurrent GBM. However, challenges remain, including the need for patient stratification, the optimization of treatment regimens, and the identification of mechanisms of resistance. This review aims to highlight the current understanding of mechanisms underlying MET dysregulation in GBM. In addition, it will focus on the ongoing preclinical and clinical assessment of therapies targeting MET dysregulation in GBM.

Abstract 6402: The effects of cytotoxic chemotherapy on colorectal cancer immunogenicity

Abstract Introduction: Immunotherapy based on PD1/PDL1 and/or CTLA4 blocking antibodies has shown efficacy in the molecular subgroup of colorectal cancers (CRCs) characterized by deficient mismatch repair (MMRd). This feature, present in only 4-5% of metastatic CRCs, causes a significant increase of tumor mutational burden (TMB) and tumor neoantigens, ultimately leading to immune rejection. On the other hand, for the majority of MMR proficient (MMRp) CRCs, cytotoxic chemotherapy ± targeted agents still constitute the mainstay of the treatment Interestingly, even though it is known that cytotoxic agents induce mutations, their immunogenic potential is still not fully understood. The aim of this work is to systematically investigate the immunogenicity of chemotherapy-induced mutations in CRC. Methods: We performed a two-step experiment: first, murine CRC models were exposed to chemotherapy agents in an immune-free context (priming phase) and then challenged in immune-deficient and -proficient contexts (editing phase). Chemotherapy agents included the commonly used cytotoxic drugs 5-fluorouracil (5FU), oxaliplatin, SN38 (the active metabolite of irinotecan), cisplatin, and temozolomide, used as single drugs or combinations, in a pulsatile schedule using weekly ‘cycles’ (2 days on/5 days off) in order to mimic drug exposure in clinical settings. Whole exome sequencing (WES) was performed at baseline, and after both the priming and the editing phases. Results and discussion: WES analysis showed that cisplatin-based treatment is associated with the highest increase in TMB and predicted neoantigens when compared to 5FU-based combinations. Multiple mutational processes contribute to the accumulation of mutations upon exposure to chemotherapy, as revealed by analysis of mutational signatures. A statistically significant growth delay and increased survival was reported for tumors primed with cisplatin/temozolomide and 5FU/Oxaliplatin/SN38 (FOLFOXIRI) combinations compared to unprimed tumors in immunocompetent but not in immunodeficient mice, suggesting the active involvement of the immune system in controlling tumor growth. Sequencing data of residual (escaped) tumors at the end of the editing phase revealed a preferential loss of mutations etiologically linked to chemotherapy in the immunocompetent models, pinpointing an active immune-editing of chemotherapy-induced mutations. Conclusions: Cisplatin/temozolomide and FOLFOXIRI treatment effectively prime murine CRC models for subsequent immune rejection. These results suggest that the anticancer effect of chemotherapy treatment may be in part mediated by the immune-editing of chemotherapy-induced mutant cancer subclones. Citation Format: Pietro Paolo Vitiello, Rosaria Chilà, Giuseppe Rospo, Gaia Grasso, Giovanni Crisafulli, Alice Bartolini, Vito Amodio, Federica Di Nicolantonio, Giovanni Germano, Alberto Bardelli. The effects of cytotoxic chemotherapy on colorectal cancer immunogenicity. [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6402.

Abstract PD9-09: Molecular differences between younger versus older estrogen receptor positive/human epidermal growth factor receptor-2 negative breast cancers

Abstract Background: The RxPONDER and TAILORx trials demonstrated benefit from adjuvant chemotherapy in patients < 50 years with node-positive breast cancer and Recurrence Score (RS) 0-25, and with node-negative disease and RS 16-25, respectively. Neither trial showed benefit in older women with RS < 26. It is unclear what explains the interaction between age and adjuvant chemotherapy benefit. Methods: We analyzed transcriptomic and genomic data from n=4,507 ER+/HER2- breast cancers to compare differences in estrogen receptor (ER), proliferation, and immune-related gene expressions, and somatic mutation patterns and mutation burden between younger (< 50 years of age) and older (>55 years) patients. We restricted our analysis to patients in the lower 80% range of in silico RS distribution to mimic the RxPONDER and TAILORx populations. Results: Five data sets were analyzed independently to assess consistency of results (TCGA n=530; microarray cohort A n=865; Cohort B n=609, METABRIC n=867, SCAN-B n=1636). Older patients had significantly higher somatic mutation burden and more frequent copy number gain in ESR1, LATS1, ARID1B, SGK1, and MYB genes (odds ratio [OR] > 8.5, FDR< 0.05), but lower frequency of GATA3 mutations (12% versus 26%, P< 0.0001). Younger patients had higher rate of ESR1 copy number loss (OR: 0.45, FDR: 0.03). There was no difference in proliferation-related gene expression. ESR1 mRNA expression was significantly lower in younger women in all cohorts (P < 0.001). A regression model of ESR1 mRNA expression using age and ER IHC positivity indicated that lower ER expression in younger patients is primarily driven by lower ESR1 mRNA per cancer cell and not by fewer ER positive cells. We also assessed four gene signatures associated with endocrine therapy sensitivity including a 4-gene ERS, a 7-gene ERS-Lum, a 106-gene ERS-Pos signature, and a 59-gene ERS-Neg signature associated with endocrine resistance. In the TCGA and METABRIC cohorts, the ERS, ERS-Lum, and ERS-Pos signatures were all lower (FDR< 0.03) while the ERS-Neg signature was higher (FDR< 0.001) in younger patients. Similarly, in both microarray cohorts, and in the SCAN-B-cohort, the ERS-Pos signature was lower and the ERS-Neg signature was higher in younger patients (FDR< 0.002). Next, we assessed 4 different immune cell signatures that have been associated with response to chemotherapy. In the TCGA, B-cell, T-cell, Mast-cell, and TIS signatures were significantly higher (FDR<.05). In the microarray Cohort-A, B cells and mast cells were significantly higher, and the T cell and TIS signatures showed a trend for higher expression. In Cohort-B, T cells, B cells, TIS, and dendritic cells signatures were significantly higher in younger patients. Significantly higher expression of immune gene signatures in younger patients were also seen in the METABRIC and SCAN-B data sets. The ER-related and immune-related gene signatures showed negative correlation and joint analysis defined three subpopulations in younger women: (i) immune-high/ER-low, (ii) immune-intermediate/ER-intermediate and (iii) immune-low/ER-intermediate, whereas in older women the dominant pattern was immune-low/ER-high. Conclusion: ESR1 mRNA and ER-associated gene expression is lower in ER positive cancers of younger compared to older patients, while immune infiltration is higher. The cytotoxic and endocrine effects of adjuvant chemotherapy could both contribute to the survival benefit seen in younger patients, but the relative contributions of these effects may vary by ER and immune phenotype. We hypothesize that in immune-high/ER-low cancers, the cytotoxic effect of chemotherapy may drive the benefit, whereas in immune-low/ER-intermediate cancers chemotherapy induced ovarian suppression may play a more important role. Citation Format: Tao Qing, Thomas Karn, Mariya Rozenblit, Julia Foldi, Michal Marczyk, Naing Lin Shan, Kim Blenman, uwe Holtrich, Kevin Kalinsky, Funda Meric-Bernstam, Lajos Pusztai. Molecular differences between younger versus older estrogen receptor positive/human epidermal growth factor receptor-2 negative breast cancers [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr PD9-09.

Predicting the effect of a combination drug therapy on the prostate tumor growth via an improvement of a direct radial basis function partition of unity technique for a diffuse-interface model

Chemotherapy is usually applied to treat advanced prostate cancer that cancer cells spread outside the prostate gland. The treatment uses cytotoxic drugs to target cells that grow and divide quickly. On the other hand, the growth of such cancerous tumors depends on angiogenesis. In this paper, we numerically study a diffuse-interface model in a two-dimensional space related to the therapies of prostate cancer. The proposed model describes the tumor growth driven by a generic nutrient and producing the prostate-specific antigen. More precisely, the effect of cytotoxic chemotherapy in the model is evaluated by considering a time-dependent function in the tumor dynamics. Also, another function related to the antiangiogenic therapy is considered to show the reducing intratumoral nutrient supply in the nutrient dynamics. Here, a meshless approximation, i.e., a generalized form of the direct radial basis function partition of unity (D-RBF-PU) method is presented for finding the numerical simulations of this model utilizing in medical oncology. The method uses the lower number of trial points in each patch than the original D-RBF-PU scheme for approximating the trial function per test point. Hence, the time complexity of the method is less than the D-RBF-PU technique. Besides, a semi-implicit time discretization of order 1 has been used to deal with the time variable. Consequently, a linear system of algebraic equations could be solved iteratively per time step by the use of the biconjugate gradient stabilized method with zero-fill incomplete lower–upper preconditioner. Finally, the obtained results without using any adaptive algorithm demonstrate the response of the prostate tumor growth to the chemotherapy, antiangiogenic therapy and a combined therapy.

CYTOMORPHOLOGICAL CHANGES IN MCF7-DOX CELLS AND THEIR CORRELATION WITH THE ACTIVITY OF THE CELL CYCLE REGULATOR P21 AFTER COMBINED EXPOSURE TO INFRARED LASER AND DOXORUBICIN

Introduction: In recent years, studies of infrared laser irradiation effect on tumor cells in combination with various chemotherapeutic agents have been developing dynamically. Objective: To study the effect of infrared laser in combination with low doses of doxorubicin on cytomorphological characteristics of MCF-7DOX culture cells and p21 expression level. Materials and Methods: MCF-7DOX tumor cells were cultured in DMEM medium with 10% fetal calf serum (FCT) and 40 μg/ml gentamicin. Doxorubicin was added to the cells to a final concentration of 2 μg/ml and 0.5 μg/ml. Cells were irradiated with infrared laser (Fotonika-Plus, Ukraine) with a wavelength of 810 nm (irradiation time — 5 min, power density — 50 mV/cm², irradiation dose 15 J/cm²). Photomicrographs of cells were taken using a Carl Zeiss microscope, Germany. An immunocytochemical study was also conducted using monoclonal antibodies to the factor p21 (Thermo Scientific, USA). Results: The evaluation of morphological characteristics in micropreparations testifies to the antitumor effectiveness of the combined effect of infrared laser irradiation and doxorubicin. It is noteworthy that the cytotoxic effects of chemotherapy in combination with photobiomodulation were observed when using different doses of doxorubicin: 2 μg/ml and 0.5 μg/ml. When studying the biological activity of cells using immunocytochemistry, it was established that the combination of doxorubicin and infrared laser irradiation led to an increase in the expression of p21, and it is important to note that a similar effect was observed at both concentrations of doxorubicin: as at 2.0 μg/ ml and 0.5 μg/ml. The simultaneous destructive effect on tumor cells and the increase in p21 expression allows us to make a preliminary cautious assumption that the proposed technique of combination of infrared laser irradiation with doxorubicin determines the effect of the p21 factor in the role of a tumor suppressor. Conclusions: The results of the study allow us to consider the use of doxorubicin in combination with infrared laser as a promising method of cytotoxic effect on tumor cells.

Mild oxidative stress protects against chemotherapy-induced hair loss.

Chemotherapy induces hair loss in most cancer patients who undergo treatment, which causes them significant psychosocial trauma. Scalp cooling has demonstrated some efficacy in attenuating chemotherapy-induced alopecia, but response rate varies between patients and chemotherapy class. Here, we showcase in rats a proof-of-concept treatment of using subcutaneous hydrogen peroxide and cumene hydroperoxide injections to provide total protection from hair loss against multiple classes of chemotherapy. We found that subcutaneous peroxides induce cell cycle arrest via P53 activation, thereby protecting hair follicles from the cytotoxic effects of chemotherapy on actively dividing cells. This treatment represents a highly effective and accessible way for cancer patients to maintain quality of life while undergoing treatment for cancer.

Mirvetuximab Soravtansine in Platinum-Resistant Ovarian Cancer.

Ovarian cancer is the second leading cause of death from gynecologic malignancies worldwide. Management of platinum-resistant disease is challenging and clinical outcomes with standard chemotherapy are poor. Over the past decades, significant efforts have been made to understand drug resistance and develop strategies to overcome treatment failure. Antibody drug conjugates (ADCs) are a rapidly growing class of oncologic therapeutics, which combine the ability to target tumor-specific antigens with the cytotoxic effects of chemotherapy. Mirvetuximab soravtansine is an ADC comprising an IgG1 monoclonal antibody against the folate receptor alpha (FRα) conjugated to the cytotoxic maytansinoid effector molecule DM4 that has shown promising clinical activity in patients with FR-α-positive ovarian cancer. This review summarizes current evidence of mirvetuximab soravtansine in platinum-resistant ovarian cancer, focusing on clinical activity, toxicity, and future directions.

Resistance Mechanisms to Anti-Epidermal Growth Factor Receptor Therapy in RAS/RAF Wild-Type Colorectal Cancer Vary by Regimen and Line of Therapy.

Acquired resistance to anti-epidermal growth factor receptor (EGFR) inhibitor (EGFRi) therapy in colorectal cancer (CRC) has previously been explained by the model of acquiring new mutations in KRAS/NRAS/EGFR, among other MAPK-pathway members. However, this was primarily on the basis of single-agent EGFRi trials and little is known about the resistance mechanisms of EGFRi combined with effective cytotoxic chemotherapy in previously untreated patients. We analyzed paired plasma samples from patients with RAS/BRAF/EGFR wild-type metastatic CRC enrolled in three large randomized trials evaluating EGFRi in the first line in combination with chemotherapy and as a single agent in third line. The mutational signature of the alterations acquired with therapy was evaluated. CRC cell lines with resistance to cetuximab, infusional fluorouracil, leucovorin, and oxaliplatin, and SN38 were developed, and transcriptional changes profiled. Patients whose tumors were treated with and responded to EGFRi alone were more likely to develop acquired mutations (46%) compared with those treated in combination with cytotoxic chemotherapy (9%). Furthermore, contrary to the generally accepted hypothesis of the clonal evolution of acquired resistance, we demonstrate that baseline resistant subclonal mutations rarely expanded to become clonal at progression, and most remained subclonal or disappeared. Consistent with this clinical finding, preclinical models with acquired resistance to either cetuximab or chemotherapy were cross-resistant to the alternate agents, with transcriptomic profiles consistent with epithelial-to-mesenchymal transition. By contrast, commonly acquired resistance alterations in the MAPK pathway do not affect sensitivity to cytotoxic chemotherapy. These findings support a model of resistance whereby transcriptomic mechanisms of resistance predominate in the presence of active cytotoxic chemotherapy combined with EGFRi, with a greater predominance of acquired MAPK mutations after single-agent EGFRi. The proposed model has implications for prospective studies evaluating EGFRi rechallenge strategies guided by acquired MAPK mutations, and highlights the need to address transcriptional mechanisms of resistance.

Molecular differences between younger versus older ER-positive and HER2-negative breast cancers

The RxPONDER and TAILORx trials demonstrated benefit from adjuvant chemotherapy in patients age ≤ 50 with node-positive breast cancer and Recurrence Score (RS) 0–26, and in node-negative disease with RS 16–25, respectively, but no benefit in older women with the same clinical features. We analyzed transcriptomic and genomic data of ER+/HER2− breast cancers with in silico RS < 26 from TCGA (n = 530), two microarray cohorts (A: n = 865; B: n = 609), the METABRIC (n = 867), and the SCAN-B (n = 1636) datasets. There was no difference in proliferation-related gene expression between age groups. Older patients had higher mutation burden and more frequent ESR1 copy number gain, but lower frequency of GATA3 mutations. Younger patients had higher rate of ESR1 copy number loss. In all datasets, younger patients had significantly lower mRNA expression of ESR1 and ER-associated genes, and higher expression of immune-related genes. The ER- and immune-related gene signatures showed negative correlation and defined three subpopulations in younger women: immune-high/ER-low, immune-intermediate/ER-intermediate, and immune-low/ER-intermediate. We hypothesize that in immune-high cancers, the cytotoxic effect of chemotherapy may drive the benefit, whereas in immune-low/ER-intermediate cancers chemotherapy induced ovarian suppression may play important role.

Diabetes mellitus and association with outcome in pembrolizumab treated patients with non-small cell lung cancer.

e21079 Background: Pembrolizumab and other immune check-point inhibitors became the mainstay of treatment in ample malignancies, including non-small cell lung cancer (NSCLC). Diabetes mellitus (DM) is a highly prevalent chronic metabolic disease. Though DM causes immune dysfunction, the effect of DM on immunotherapy efficacy has not been addressed. Methods: Medical records of consecutive NSCLC patients treated with first-line pembrolizumab alone or combined with chemotherapy at Tel Aviv Medical Center from January 2017 to July 2021 were reviewed. We excluded patients who received a single cycle or were lost to follow-up. Results: Of 234 patients reviewed, 203 were included in the analysis. The median age was 69 years, 128 were men (63%), 152 had adenocarcinoma (75%), 105 received monotherapy pembrolizumab (52%), and 51 patients had DM (25%). Diabetic patients were older (73 vs. 67, p &lt; 0.001) and had a higher mean body index (27 vs. 24, P &lt; 0.001). Median progression free survival (PFS) and overall survival (OS) were significantly shorter in diabetic compared to non-diabetic patients (5.9 vs. 7.1 months, respectively, p = 0.004, and OS 12 vs. 21 months, respectively, p = 0.006). The difference in OS was more pronounced for patients receiving pembrolizumab alone (12 vs. 27 months, p = 0.03), than for those receiving pembrolizumab together with chemotherapy (14.3 vs. 19.4 months, p = 0.06). This suggests that DM is mainly determinantal to anti-tumor immunity and not to the cytotoxic effect of chemotherapy. Multivariate analysis indicated DM as an independent risk factor for inferior PFS (HR 1.7, 95% CI 1.11-2.5, p = 0.014) and OS (HR 1.7, 95% CI 1.09-2.76, p = 0.02). Conclusions: Here we show a potential deleterious effect of DM on the efficacy of pembrolizumab in metastatic NSCLC patients. If further validated, the administration of single agent pembrolizumab in this setting should be reconsidered.

Analgesic and preventive effects of donepezil in animal models of chemotherapy-induced peripheral neuropathy: Involvement of spinal muscarinic acetylcholine M2 receptors

BackgroundDonepezil, a cholinesterase inhibitor approved in Alzheimer’s disease, has demonstrated analgesic and preventive effects in animal models of oxaliplatin-induced neuropathy. To improve the clinical interest of donepezil for the management and prevention of chemotherapy-induced peripheral neuropathy (CIPN), a broader validation is required in different animal models of CIPN. Methods: using rat models of CIPN (bortezomib, paclitaxel, and vincristine), the analgesic and preventive efficacies of donepezil were evaluated on tactile, cold and heat hypersensitivities. The involvement of muscarinic M2 acetylcholine receptors (m2AChRs) in analgesic effects was investigated at the spinal level. The absence of interference of donepezil with the cytotoxic effect of chemotherapy has been controlled in cancer cell lines. Results: the analgesic efficacy of donepezil was demonstrated for all CIPN models, mainly on tactile hypersensitivity (maximal efficacy at 60 min, p < 0.05 vs. vehicle group). This effect was suppressed by an intrathecal injection of methoctramine (m2AChR antagonist). Regarding preventive effects, donepezil limited tactile hypersensitivity induced by paclitaxel, but not for other CIPN models. Donepezil did not modify the viability of cancer cells or the efficacy of anticancer drugs. Conclusions: donepezil had a broad analgesic effect on animal models of CIPN and this effect involved spinal m2AChRs. This work validates the repositioning of donepezil in the management of CIPN.

Central Nervous System Delivery of the Catalytic Subunit of DNA-Dependent Protein Kinase Inhibitor Peposertib as Radiosensitizer for Brain Metastases.

Cytotoxic effects of chemotherapy and radiation therapy (RT) used for the treatment of brain metastases results from DNA damage within cancer cells. Cells rely on highly evolved DNA damage response (DDR) pathways to repair the damage caused by these treatments. Inhibiting these repair pathways can further sensitize cancer cells to chemotherapy and RT. The catalytic subunit of DNA-dependent protein kinase, in a complex with Ku80 and Ku70, is a pivotal regulator of the DDR, and peposertib is a potent inhibitor of this catalytic subunit. The characterization of central nervous system (CNS) distributional kinetics of peposertib is critical in establishing a therapeutic index in the setting of brain metastases. Our studies demonstrate that the delivery of peposertib is severely restricted into the CNS as opposed to peripheral organs, by active efflux at the blood-brain barrier (BBB). Peposertib has a low free fraction in the brain and spinal cord, further reducing the active concentration, and distributes to the same degree within different anatomic regions of the brain. However, peposertib is heterogeneously distributed within the metastatic tumor, where its concentration is highest within the tumor core (with disrupted BBB) and substantially lower within the invasive tumor rim (with a relatively intact BBB) and surrounding normal brain. These findings are critical in guiding the potential clinical deployment of peposertib as a radiosensitizing agent for the safe and effective treatment of brain metastases. SIGNIFICANCE STATEMENT: Effective radiosensitization of brain metastases while avoiding toxicity to the surrounding brain is critical in the development of novel radiosensitizers. The central nervous system distribution of peposertib, a potent catalytic subunit of DNA-dependent protein kinase inhibitor, is restricted by active efflux in the normal blood-brain barrier (BBB) but can reach significant concentrations in the tumor core. This finding suggests that peposertib may be an effective radiosensitizer for intracranial tumors with an open BBB, while limited distribution into normal brain will decrease the risk of enhanced radiation injury.

Oncobox molecular profiling for a patient with recurrent endometrial cancer

Relevance. Endometrial cancer (EC) is the most common gynecological tumor. As a rule, it has a good prognosis, but in case of relapse, it worsens significantly. The effectiveness of cytotoxic chemotherapy for the treatment of such patients remains low.Purpose. To present a clinical case demonstrating the possibilities of therapy performed according to the results of molecular profiling of the tumor by RNA sequencing methods.Methods. Analysis of the anamnesis data, the results of histological and immunohistochemical studies, PET-CT, ultrasound images, and RNA sequencing data was carried out. The results of therapy prescribed in accordance with the rating of targeted drugs obtained after processing the transcriptomic profile by the Oncobox diagnostic platform were evaluated.Results. After experimental second-line therapy, a partial response was recorded.Conclusion. Early molecular profiling and therapy assignment in accordance with its results can change the course of the disease and improve the quality of life of patients.

ABCL-262: Lymphocyte Subpopulation Dynamics in a Model of Cytotoxic Stress Caused by R(G)-DHAP

Context Anti-tumor effects in patients with non-Hodgkin lymphomas (NHL) receiving chemotherapy are achieved as a result of the synergy between cytotoxic effects of chemotherapy and anti-tumor autoimmunity. However, chemotherapeutic depletion of lymphoid cells may impair the effectiveness of the anti-tumor immune response. The dynamics of lymphocyte subpopulations during R(G)-DHAP therapy has not been previously analyzed and are of interest. Objective To analyze changes in lymphocyte fractions and determination of the time period for the restoration of T-cell and NK-cell immunity. Design The study included 5 patients with NHL. Lymphocyte subpopulations were examined at 6–7 time points: before treatment, on the 1st, 5th, 8th, 11th, 16th days of the inter-course break and before the start of the next cycle. Setting Analysis of the subpopulations of lymphocytes was performed using flow cytometry with a panel of antibodies for lymphocytes (CD45+), T-helper cells (CD3+CD4+), cytotoxic T-cells (CD3+CD8+), NK cells (CD3-CD56+) and B-lymphocytes (CD19+). Patients Inclusion criterion: NHL patients receiving R(G)-DHAP chemotherapy. Main Outcomes Measures Estimation of time parameters of dynamics of lymphocyte subpopulations. Results The number of lymphocytes critically decreases on the 1st day of the break after (R/G)-DHAP and gradually increased. CD8+ cells are most sensitive to chemotherapy. The number of CD4+ lymphocytes is characterized by the formation of a second minimum on the 10th–12th day of the inter-course break, while the dynamics of effector cytotoxic lymphocytes and NK cells is more linear and gradually increases. By day 16, the absolute number of lymphocytes is restored or approaching the level before the start of chemotherapy. Conclusions The parameters of the dynamics of lymphocytes under cytotoxic stress can be taken into account in the case of combined use of chemotherapy and immunotherapy.

Autophagy Inhibition in BRAF-Driven Cancers.

Simple SummaryBRAF is a protein kinase that is frequently mutationally activated in cancer. Mutant BRAF can be pharmacologically inhibited, which in combination with blockade of its direct effector, MEK1/2, is an FDA-approved therapeutic strategy for several BRAF-mutated cancer patients, such as melanoma, non-small-cell lung carcinoma, and thyroid cancer. However, therapy resistance is a major clinical challenge, highlighting the need for comprehensive investigations on the biological causes of such resistance, as well as to develop novel therapeutic strategies to improve patient survival. Autophagy is a cellular recycling process, which has been shown to allow cancer cells to escape from BRAF inhibition. Combined blockade of autophagy and BRAF signaling is a novel therapeutic strategy that is currently being tested in clinical trials. This review describes the relationship between BRAF-targeted therapy and autophagy regulation and discusses possible future treatment strategies.Several BRAF-driven cancers, including advanced BRAFV600E/K-driven melanoma, non-small-cell lung carcinoma, and thyroid cancer, are currently treated using first-line inhibitor combinations of BRAFV600E plus MEK1/2. However, despite the success of this vertical inhibition strategy, the durability of patient response is often limited by the phenomenon of primary or acquired drug resistance. It has recently been shown that autophagy, a conserved cellular recycling process, is increased in BRAF-driven melanoma upon inhibition of BRAFV600E signaling. Autophagy is believed to promote tumor progression of established tumors and also to protect cancer cells from the cytotoxic effects of chemotherapy. To this end, BRAF inhibitor (BRAFi)-resistant cells often display increased autophagy compared to responsive lines. Several mechanisms have been proposed for BRAFi-induced autophagy, such as activation of the endoplasmic reticulum (ER) stress gatekeeper GRP78, AMP-activated protein kinase, and transcriptional regulation of the autophagy regulating transcription factors TFEB and TFE3 via ERK1/2 or mTOR inhibition. This review describes the relationship between BRAF-targeted therapy and autophagy regulation, and discusses possible future treatment strategies of combined inhibition of oncogenic signaling plus autophagy for BRAF-driven cancers.