Diversity of the Senescence Phenotype of Cancer Cells Treated with Chemotherapeutic Agents

Abstract

It is acknowledged that cancer cells are able to undergo senescence in response to clinically used chemotherapeutics. Moreover, recent years have provided evidence that some drugs can selectively remove senescent cells. Therefore, it is essential to properly identify and characterize senescent cells, especially when it comes to cancer. Senescence was induced in various cancer cell lines (A549, SH-SY-5Y, HCT116, MDA-MB-231, and MCF-7) following treatment with doxorubicin, irinotecan, methotrexate, 5-fluorouracil, oxaliplatin, or paclitaxel. Treatment with tested chemotherapeutics resulted in upregulation of p21 and proliferation arrest without cytotoxicity. A comparative analysis with the use of common senescence markers (i.e., morphology, SA-β-galactosidase, granularity, secretory phenotype, and the level of double-stranded DNA damage) revealed a large diversity in response to the chemotherapeutics used. The strongest senescence inducers were doxorubicin, irinotecan, and methotrexate; paclitaxel had an intermediate effect and oxaliplatin and 5-fluorouracil did not induce senescence. In addition, different susceptibility of cancer cells to senescence was observed. A statistical analysis aimed at finding any relationship between the senescence markers applied did not show clear correlations. Moreover, increased SA-β-gal activity coupled with p21 expression proved not to be an unequivocal senescence marker. This points to a need to simultaneously analyze multiple markers, given their individual limitations.

Therapy-Induced Senescence: An “Old” Friend Becomes the Enemy

“…SA-β-gal, p21 Cip1 , p16 INK4a , SASP (IL-1α, IL-6, Mmp-3, Mmp-9, Cxcl-1, Cxcl-10 and Ccl20), reduced Lamin B1 [28] SH-SY-5Y p21 Cip1 , low Ki67, growth arrest, SA-β-gal [43] HCT116 p21 Cip1 , low Ki67, growth arrest, SA-β-gal, increased granularity, morphology, SASP (IL-8), γH2AX [43] MDA-MB-231 p21 Cip1 , growth arrest, SA-β-gal, morphology, SASP (IL-6, IL-8, VEGF), γH2AX [43] MCF-7 p21 Cip1 , low Ki67, growth arrest, SA-β-gal, increased granularity, morphology, γH2AX [43] A549 p21 Cip1 , low Ki67, growth arrest, SA-β-gal, increased granularity, morphology, SASP (IL-6, IL-8), γH2AX [43] Daunorubicin Jurkat cells SA-β-gal, growth arrest [44] Etoposide HepG2, U2OS SA-β-gal, p53, p21 Cip1 [45] IMR-90, MEFs, BJ SA-β-gal, growth arrest, p16 INK4 , p21 Cip1 , p53 [46] BJ, MEFs, B16F10 SA-β-gal, SASP (IL-6, IL-8, IL-1β) [47] NRK-52E Morphology, SA-β-gal, growth arrest, p53, p21 Cip1 [48] Follicular lymphoma 3D model SA-β-gal [49] [50] A549, WI38 Growth arrest, SA-β-gal, yH2AX, morphology [51] Camptothecin HCT116 SA-β-gal, morphology, SAHF, reduced BrdU incorporation [52] HCT116, RKO SA-β-gal, morphology [53] HeLa, MCF7 SA-β-gal, morphology [54] MNA, STA-NB-10, CLB-Ma mouse xenograft (MYCN-amplified neuroblastoma)…”

“…Platinum-based Cisplatin A375, B16F10, B16F10 xenografts SASP, SA-β-gal [64] A2780 SAHF (HP1-γ), morphology, SA-β-gal [68] CNE1 Growth arrest, morphology, SA-β-gal [30] SKOV3, TOV-21G Morphology, SA-β-gal [69] HepG2, SMMC-7721 SA-β-gal, p53, p21 Cip1 , p16 INK4 [70] Follicular lymphoma 3D model SA-β-gal [49] In vivo mouse model (p16-3MR) p16 INK4 [28] Carboplatin H1299, patients' lung tumor samples Cell cycle arrest, SA-β-gal, p16 INK4 , RB, downregulation of cyclin B1 and cyclin D1 [71] Oxaliplatin PROb, CT26 SA-β-gal [72] HepG2, SMMC-7721, patients' colorectal tumor samples SA-β-gal [73] Antimetabolites Methotrexate C85 p53 [74] C85 SA-β-gal [75] MCF-7 SA-β-gal [76] Rat-derived BMSCs and ADSCs SA-β-gal [42] A549 p21 Cip1 , low Ki67, growth arrest, SA-β-gal, increased granularity, morphology, SASP (IL-6, IL-8), γH2AX [43] SH-SY-5Y p21 Cip1 , growth arrest, SA-β-gal, γH2AX [43] HCT116 p21 Cip1 , low Ki67, growth arrest, SA-β-gal, increased granularity, morphology, SASP (IL-8), γH2AX [43] MDA-MB-231 p21 Cip1 , growth arrest, SA-β-gal, morphology, SASP (IL-6, IL-8, VEGF) [43] MCF-7 p21 Cip1 , low Ki67, growth arrest, SA-β-gal, increased granularity, morphology, γH2AX [43] Pemetrexed H1650, A549, H2228, H292, H226 and H1650, A549 xenografts SA-β-gal, morphology, SASP (IL-6, IL-8, IL-1β and MCP-1) [77] A549 SASP, SA-β-gal [78] Gemcitabine Miapaca-2 and Panc-1 SA-β-gal [79] AsPc1, Panc1 SA-β-gal [80] Azacitidine U2OS, MCF7 SA-β-gal, p53, growth arrest [81] TPC-1 SA-β-gal [82] KKU100, HuCCA1, RMCCA1 Morphology, SA-β-gal [83] DU145, LNCaP Morphology, growth arrest, polyploidy [40] Bromodeoxyuridine MNA, STA-NB-10, CLB-Ma mouse xenograft (MYCN-amplified neuroblastoma)…”

“…In this context, it should be emphasized that the literature discussed in the subsequent section on reversion from cell cycle arrest reflect studies that were performed predominantly in in vitro models, where the use and interpretation of senescence markers is relatively reliable. Nevertheless, a recent report by Bojko et al, highlights the limitations of these markers and how even the presentation of TIS in vitro can be highly diverse [43]. Our current ability to capture and to quantify senescence in vivo is limited and the identification of reproducible, reliable and validated markers of senescence in patient tissues would be critical for establishing the extent to which senescence contributes to either the effectiveness of therapy, in terms of a durable growth arrest, and/or the capacity of senescent tumor cells to ultimately recover and re-emerge as a recurrent (and possibly more aggressive) form of disease [155].…”

Intratumor Heterogeneity and Therapy Resistance: Contributions of Dormancy, Apoptosis Reversal (Anastasis) and Cell Fusion to Disease Recurrence

“…Furthermore, p21 forms a positive feedback loop with ATM, and this interaction has been shown to underlie the apoptosis resistance of cancer cells that have undergone SIPS following treatment with chemotherapeutic agents [78]. Cancer cells lacking wild-type p53 activity can also undergo SIPS through p21-dependent [79,80] and independent mechanisms [81]. In addition to p21, CDK inhibitors that can drive SIPS include p16 INK4a , p15 INK4b , and p27 KIP1 [80][81][82].…”

Exploring the Relevance of Senotherapeutics for the Current SARS-CoV-2 Emergency and Similar Future Global Health Threats

“…Drugs targeting IL-6 have been included among the potential strategies to inhibit the deleterious consequences of the senescence-associated secretory phenotype (SASP), the secretome produced by senescent cells [31,32]. The SASP includes cytokines, chemokines, proteases, and growth factors, recently collected in a proteomic database [29], which functionally links the accumulation of senescent cells with its pathological processes [33,34]. However, the SASP appears to be beneficial or deleterious, depending on the biological context.…”